[PATCH v5 00/21] Introduce power-off+restart call chain API

[PATCH v5 00/21] Introduce power-off+restart call chain API

[Dmitry Osipenko]

Problem
-------

SoC devices require power-off call chaining functionality from kernel.
We have a widely used restart chaining provided by restart notifier API,
but nothing for power-off.

Solution
--------

Introduce new API that provides both restart and power-off call chains.

Why combine restart with power-off? Because drivers often do both.
More practical to have API that provides both under the same roof.

The new API is designed with simplicity and extensibility in mind.
It's built upon the existing restart and reboot APIs. The simplicity
is in new helper functions that are convenient for drivers. The
extensibility is in the design that doesn't hardcode callback
arguments, making easy to add new parameters and remove old.

This is a third attempt to introduce the new API. First was made by
Guenter Roeck back in 2014, second was made by Thierry Reding in 2017.
In fact the work didn't stop and recently arm_pm_restart() was removed
from v5.14 kernel, which was a part of preparatory work started by
Guenter Roeck. I took into account experience and ideas from the
previous attempts, extended and polished them.

Adoption plan
-------------

This patchset introduces the new API. It also converts multiple drivers
and arch code to the new API to demonstrate how it all looks in practice.

The plan is:

1. Merge new API (patches 1-8). This API will co-exist with the old APIs.

2. Convert arch code to do_kernel_power_off() (patches 9-21).

3. Convert drivers and platform code to the new API.

4. Remove obsolete pm_power_off and pm_power_off_prepare variables.

5. Make restart-notifier API private to kernel/reboot.c once no users left.

6. Make uniqueness of the handlers' priority a mandatory requirement.

It's fully implemented here:

[1] https://github.com/grate-driver/linux/commits/sys-off-handler

For now I'm sending only the first 25 base patches out of ~180. It's
preferable to squash 1-2, partially 3 and 4 points of the plan into a
single patchset to ease and speed up applying of the rest of the patches.
Majority of drivers and platform patches depend on the base, hence they
will come later (and per subsystem), once base will land.

All [1] patches are compile-tested. Tegra and x86 ACPI patches are tested
on hardware. The remaining should be covered by unit tests (unpublished).

Results
-------

1. Devices can be powered off properly.

2. Global variables are removed from drivers.

3. Global pm_power_off and pm_power_off_prepare callback variables are
removed once all users are converted to the new API. The latter callback
is removed by patch #25 of this series.

4. Ambiguous call chain ordering is prohibited. See patch #5 which adds
verification of restart handlers priorities, ensuring that they are unique.

Changelog:

v5: - Dropped patches which cleaned up notifier/reboot headers, as was
      requested by Rafael Wysocki.

    - Dropped WARN_ON() from the code, as was requested by Rafael Wysocki.
      Replaced it with pr_err() appropriately.

    - Dropped *_notifier_has_unique_priority() functions and added
      *_notifier_chain_register_unique_prio() instead, as was suggested
      by Michał Mirosław and Rafael Wysocki.

    - Dropped export of blocking_notifier_call_chain_is_empty() symbol,
      as was suggested by Rafael Wysocki.

    - Michał Mirosław suggested that will be better to split up patch
      that adds the new API to ease reviewing, but Rafael Wysocki asked
      not add more patches, so I kept it as a single patch.

    - Added temporary "weak" stub for pm_power_off() which fixes linkage
      failure once symbol is removed from arch/* code. Previously I missed
      this problem because was only compile-testing object files.

v4: - Made a very minor improvement to doc comments, clarifying couple
      default values.

    - Corrected list of emails recipient by adding Linus, Sebastian,
      Philipp and more NDS people. Removed bouncing emails.

    - Added acks that were given to v3.

v3: - Renamed power_handler to sys_off_handler as was suggested by
      Rafael Wysocki.

    - Improved doc-comments as was suggested by Rafael Wysocki. Added more
      doc-comments.

    - Implemented full set of 180 patches which convert whole kernel in
      accordance to the plan, see link [1] above. Slightly adjusted API to
      better suit for the remaining converted drivers.

      * Added unregister_sys_off_handler() that is handy for a couple old
        platform drivers.

      * Dropped devm_register_trivial_restart_handler(), 'simple' variant
        is enough to have.

    - Improved "Add atomic/blocking_notifier_has_unique_priority()" patch,
      as was suggested by Andy Shevchenko. Also replaced down_write() with
      down_read() and factored out common notifier_has_unique_priority().

    - Added stop_chain field to struct restart_data and reboot_prep_data
      after discovering couple drivers wanting that feature.

    - Added acks that were given to v2.

v2: - Replaced standalone power-off call chain demo-API with the combined
      power-off+restart API because this is what drivers want. It's a more
      comprehensive solution.

    - Converted multiple drivers and arch code to the new API. Suggested by
      Andy Shevchenko. I skimmed through the rest of drivers, verifying that
      new API suits them. The rest of the drivers will be converted once we
      will settle on the new API, otherwise will be too many patches here.

    - v2 API doesn't expose notifier to users and require handlers to
      have unique priority. Suggested by Guenter Roeck.

    - v2 API has power-off chaining disabled by default and require
      drivers to explicitly opt-in to the chaining. This preserves old
      behaviour for existing drivers once they are converted to the new
      API.

Dmitry Osipenko (21):
  notifier: Add blocking_notifier_call_chain_is_empty()
  notifier: Add atomic/blocking_notifier_chain_register_unique_prio()
  reboot: Print error message if restart handler has duplicated priority
  kernel: Add combined power-off+restart handler call chain API
  ARM: Use do_kernel_power_off()
  csky: Use do_kernel_power_off()
  riscv: Use do_kernel_power_off()
  arm64: Use do_kernel_power_off()
  parisc: Use do_kernel_power_off()
  xen/x86: Use do_kernel_power_off()
  powerpc: Use do_kernel_power_off()
  m68k: Switch to new sys-off handler API
  sh: Use do_kernel_power_off()
  x86: Use do_kernel_power_off()
  ia64: Use do_kernel_power_off()
  mips: Use do_kernel_power_off()
  nds32: Use do_kernel_power_off()
  memory: emif: Use kernel_can_power_off()
  ACPI: power: Switch to sys-off handler API
  regulator: pfuze100: Use devm_register_sys_off_handler()
  reboot: Remove pm_power_off_prepare()

 arch/arm/kernel/reboot.c               |   4 +-
 arch/arm64/kernel/process.c            |   3 +-
 arch/csky/kernel/power.c               |   6 +-
 arch/ia64/kernel/process.c             |   4 +-
 arch/m68k/emu/natfeat.c                |   3 +-
 arch/m68k/include/asm/machdep.h        |   1 -
 arch/m68k/kernel/process.c             |   5 +-
 arch/m68k/kernel/setup_mm.c            |   1 -
 arch/m68k/kernel/setup_no.c            |   1 -
 arch/m68k/mac/config.c                 |   4 +-
 arch/mips/kernel/reset.c               |   3 +-
 arch/nds32/kernel/process.c            |   3 +-
 arch/parisc/kernel/process.c           |   4 +-
 arch/powerpc/kernel/setup-common.c     |   4 +-
 arch/powerpc/xmon/xmon.c               |   3 +-
 arch/riscv/kernel/reset.c              |  12 +-
 arch/sh/kernel/reboot.c                |   3 +-
 arch/x86/kernel/reboot.c               |   4 +-
 arch/x86/xen/enlighten_pv.c            |   4 +-
 drivers/acpi/sleep.c                   |  25 +-
 drivers/memory/emif.c                  |   2 +-
 drivers/regulator/pfuze100-regulator.c |  38 +-
 include/linux/notifier.h               |   7 +
 include/linux/pm.h                     |   1 -
 include/linux/reboot.h                 | 265 +++++++++++-
 kernel/notifier.c                      | 100 ++++-
 kernel/power/hibernate.c               |   2 +-
 kernel/reboot.c                        | 574 ++++++++++++++++++++++++-
 28 files changed, 968 insertions(+), 118 deletions(-)

-- 
2.33.1


_______________________________________________
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linux-riscv@lists.infradead.org
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[PATCH v5 00/21] Introduce power-off+restart call chain API

[Dmitry Osipenko]

Problem
-------

SoC devices require power-off call chaining functionality from kernel.
We have a widely used restart chaining provided by restart notifier API,
but nothing for power-off.

Solution
--------

Introduce new API that provides both restart and power-off call chains.

Why combine restart with power-off? Because drivers often do both.
More practical to have API that provides both under the same roof.

The new API is designed with simplicity and extensibility in mind.
It's built upon the existing restart and reboot APIs. The simplicity
is in new helper functions that are convenient for drivers. The
extensibility is in the design that doesn't hardcode callback
arguments, making easy to add new parameters and remove old.

This is a third attempt to introduce the new API. First was made by
Guenter Roeck back in 2014, second was made by Thierry Reding in 2017.
In fact the work didn't stop and recently arm_pm_restart() was removed
from v5.14 kernel, which was a part of preparatory work started by
Guenter Roeck. I took into account experience and ideas from the
previous attempts, extended and polished them.

Adoption plan
-------------

This patchset introduces the new API. It also converts multiple drivers
and arch code to the new API to demonstrate how it all looks in practice.

The plan is:

1. Merge new API (patches 1-8). This API will co-exist with the old APIs.

2. Convert arch code to do_kernel_power_off() (patches 9-21).

3. Convert drivers and platform code to the new API.

4. Remove obsolete pm_power_off and pm_power_off_prepare variables.

5. Make restart-notifier API private to kernel/reboot.c once no users left.

6. Make uniqueness of the handlers' priority a mandatory requirement.

It's fully implemented here:

[1] https://github.com/grate-driver/linux/commits/sys-off-handler

For now I'm sending only the first 25 base patches out of ~180. It's
preferable to squash 1-2, partially 3 and 4 points of the plan into a
single patchset to ease and speed up applying of the rest of the patches.
Majority of drivers and platform patches depend on the base, hence they
will come later (and per subsystem), once base will land.

All [1] patches are compile-tested. Tegra and x86 ACPI patches are tested
on hardware. The remaining should be covered by unit tests (unpublished).

Results
-------

1. Devices can be powered off properly.

2. Global variables are removed from drivers.

3. Global pm_power_off and pm_power_off_prepare callback variables are
removed once all users are converted to the new API. The latter callback
is removed by patch #25 of this series.

4. Ambiguous call chain ordering is prohibited. See patch #5 which adds
verification of restart handlers priorities, ensuring that they are unique.

Changelog:

v5: - Dropped patches which cleaned up notifier/reboot headers, as was
      requested by Rafael Wysocki.

    - Dropped WARN_ON() from the code, as was requested by Rafael Wysocki.
      Replaced it with pr_err() appropriately.

    - Dropped *_notifier_has_unique_priority() functions and added
      *_notifier_chain_register_unique_prio() instead, as was suggested
      by Michał Mirosław and Rafael Wysocki.

    - Dropped export of blocking_notifier_call_chain_is_empty() symbol,
      as was suggested by Rafael Wysocki.

    - Michał Mirosław suggested that will be better to split up patch
      that adds the new API to ease reviewing, but Rafael Wysocki asked
      not add more patches, so I kept it as a single patch.

    - Added temporary "weak" stub for pm_power_off() which fixes linkage
      failure once symbol is removed from arch/* code. Previously I missed
      this problem because was only compile-testing object files.

v4: - Made a very minor improvement to doc comments, clarifying couple
      default values.

    - Corrected list of emails recipient by adding Linus, Sebastian,
      Philipp and more NDS people. Removed bouncing emails.

    - Added acks that were given to v3.

v3: - Renamed power_handler to sys_off_handler as was suggested by
      Rafael Wysocki.

    - Improved doc-comments as was suggested by Rafael Wysocki. Added more
      doc-comments.

    - Implemented full set of 180 patches which convert whole kernel in
      accordance to the plan, see link [1] above. Slightly adjusted API to
      better suit for the remaining converted drivers.

      * Added unregister_sys_off_handler() that is handy for a couple old
        platform drivers.

      * Dropped devm_register_trivial_restart_handler(), 'simple' variant
        is enough to have.

    - Improved "Add atomic/blocking_notifier_has_unique_priority()" patch,
      as was suggested by Andy Shevchenko. Also replaced down_write() with
      down_read() and factored out common notifier_has_unique_priority().

    - Added stop_chain field to struct restart_data and reboot_prep_data
      after discovering couple drivers wanting that feature.

    - Added acks that were given to v2.

v2: - Replaced standalone power-off call chain demo-API with the combined
      power-off+restart API because this is what drivers want. It's a more
      comprehensive solution.

    - Converted multiple drivers and arch code to the new API. Suggested by
      Andy Shevchenko. I skimmed through the rest of drivers, verifying that
      new API suits them. The rest of the drivers will be converted once we
      will settle on the new API, otherwise will be too many patches here.

    - v2 API doesn't expose notifier to users and require handlers to
      have unique priority. Suggested by Guenter Roeck.

    - v2 API has power-off chaining disabled by default and require
      drivers to explicitly opt-in to the chaining. This preserves old
      behaviour for existing drivers once they are converted to the new
      API.

Dmitry Osipenko (21):
  notifier: Add blocking_notifier_call_chain_is_empty()
  notifier: Add atomic/blocking_notifier_chain_register_unique_prio()
  reboot: Print error message if restart handler has duplicated priority
  kernel: Add combined power-off+restart handler call chain API
  ARM: Use do_kernel_power_off()
  csky: Use do_kernel_power_off()
  riscv: Use do_kernel_power_off()
  arm64: Use do_kernel_power_off()
  parisc: Use do_kernel_power_off()
  xen/x86: Use do_kernel_power_off()
  powerpc: Use do_kernel_power_off()
  m68k: Switch to new sys-off handler API
  sh: Use do_kernel_power_off()
  x86: Use do_kernel_power_off()
  ia64: Use do_kernel_power_off()
  mips: Use do_kernel_power_off()
  nds32: Use do_kernel_power_off()
  memory: emif: Use kernel_can_power_off()
  ACPI: power: Switch to sys-off handler API
  regulator: pfuze100: Use devm_register_sys_off_handler()
  reboot: Remove pm_power_off_prepare()

 arch/arm/kernel/reboot.c               |   4 +-
 arch/arm64/kernel/process.c            |   3 +-
 arch/csky/kernel/power.c               |   6 +-
 arch/ia64/kernel/process.c             |   4 +-
 arch/m68k/emu/natfeat.c                |   3 +-
 arch/m68k/include/asm/machdep.h        |   1 -
 arch/m68k/kernel/process.c             |   5 +-
 arch/m68k/kernel/setup_mm.c            |   1 -
 arch/m68k/kernel/setup_no.c            |   1 -
 arch/m68k/mac/config.c                 |   4 +-
 arch/mips/kernel/reset.c               |   3 +-
 arch/nds32/kernel/process.c            |   3 +-
 arch/parisc/kernel/process.c           |   4 +-
 arch/powerpc/kernel/setup-common.c     |   4 +-
 arch/powerpc/xmon/xmon.c               |   3 +-
 arch/riscv/kernel/reset.c              |  12 +-
 arch/sh/kernel/reboot.c                |   3 +-
 arch/x86/kernel/reboot.c               |   4 +-
 arch/x86/xen/enlighten_pv.c            |   4 +-
 drivers/acpi/sleep.c                   |  25 +-
 drivers/memory/emif.c                  |   2 +-
 drivers/regulator/pfuze100-regulator.c |  38 +-
 include/linux/notifier.h               |   7 +
 include/linux/pm.h                     |   1 -
 include/linux/reboot.h                 | 265 +++++++++++-
 kernel/notifier.c                      | 100 ++++-
 kernel/power/hibernate.c               |   2 +-
 kernel/reboot.c                        | 574 ++++++++++++++++++++++++-
 28 files changed, 968 insertions(+), 118 deletions(-)

-- 
2.33.1

[PATCH v5 00/21] Introduce power-off+restart call chain API

[Dmitry Osipenko]

Problem
-------

SoC devices require power-off call chaining functionality from kernel.
We have a widely used restart chaining provided by restart notifier API,
but nothing for power-off.

Solution
--------

Introduce new API that provides both restart and power-off call chains.

Why combine restart with power-off? Because drivers often do both.
More practical to have API that provides both under the same roof.

The new API is designed with simplicity and extensibility in mind.
It's built upon the existing restart and reboot APIs. The simplicity
is in new helper functions that are convenient for drivers. The
extensibility is in the design that doesn't hardcode callback
arguments, making easy to add new parameters and remove old.

This is a third attempt to introduce the new API. First was made by
Guenter Roeck back in 2014, second was made by Thierry Reding in 2017.
In fact the work didn't stop and recently arm_pm_restart() was removed
from v5.14 kernel, which was a part of preparatory work started by
Guenter Roeck. I took into account experience and ideas from the
previous attempts, extended and polished them.

Adoption plan
-------------

This patchset introduces the new API. It also converts multiple drivers
and arch code to the new API to demonstrate how it all looks in practice.

The plan is:

1. Merge new API (patches 1-8). This API will co-exist with the old APIs.

2. Convert arch code to do_kernel_power_off() (patches 9-21).

3. Convert drivers and platform code to the new API.

4. Remove obsolete pm_power_off and pm_power_off_prepare variables.

5. Make restart-notifier API private to kernel/reboot.c once no users left.

6. Make uniqueness of the handlers' priority a mandatory requirement.

It's fully implemented here:

[1] https://github.com/grate-driver/linux/commits/sys-off-handler

For now I'm sending only the first 25 base patches out of ~180. It's
preferable to squash 1-2, partially 3 and 4 points of the plan into a
single patchset to ease and speed up applying of the rest of the patches.
Majority of drivers and platform patches depend on the base, hence they
will come later (and per subsystem), once base will land.

All [1] patches are compile-tested. Tegra and x86 ACPI patches are tested
on hardware. The remaining should be covered by unit tests (unpublished).

Results
-------

1. Devices can be powered off properly.

2. Global variables are removed from drivers.

3. Global pm_power_off and pm_power_off_prepare callback variables are
removed once all users are converted to the new API. The latter callback
is removed by patch #25 of this series.

4. Ambiguous call chain ordering is prohibited. See patch #5 which adds
verification of restart handlers priorities, ensuring that they are unique.

Changelog:

v5: - Dropped patches which cleaned up notifier/reboot headers, as was
      requested by Rafael Wysocki.

    - Dropped WARN_ON() from the code, as was requested by Rafael Wysocki.
      Replaced it with pr_err() appropriately.

    - Dropped *_notifier_has_unique_priority() functions and added
      *_notifier_chain_register_unique_prio() instead, as was suggested
      by Michał Mirosław and Rafael Wysocki.

    - Dropped export of blocking_notifier_call_chain_is_empty() symbol,
      as was suggested by Rafael Wysocki.

    - Michał Mirosław suggested that will be better to split up patch
      that adds the new API to ease reviewing, but Rafael Wysocki asked
      not add more patches, so I kept it as a single patch.

    - Added temporary "weak" stub for pm_power_off() which fixes linkage
      failure once symbol is removed from arch/* code. Previously I missed
      this problem because was only compile-testing object files.

v4: - Made a very minor improvement to doc comments, clarifying couple
      default values.

    - Corrected list of emails recipient by adding Linus, Sebastian,
      Philipp and more NDS people. Removed bouncing emails.

    - Added acks that were given to v3.

v3: - Renamed power_handler to sys_off_handler as was suggested by
      Rafael Wysocki.

    - Improved doc-comments as was suggested by Rafael Wysocki. Added more
      doc-comments.

    - Implemented full set of 180 patches which convert whole kernel in
      accordance to the plan, see link [1] above. Slightly adjusted API to
      better suit for the remaining converted drivers.

      * Added unregister_sys_off_handler() that is handy for a couple old
        platform drivers.

      * Dropped devm_register_trivial_restart_handler(), 'simple' variant
        is enough to have.

    - Improved "Add atomic/blocking_notifier_has_unique_priority()" patch,
      as was suggested by Andy Shevchenko. Also replaced down_write() with
      down_read() and factored out common notifier_has_unique_priority().

    - Added stop_chain field to struct restart_data and reboot_prep_data
      after discovering couple drivers wanting that feature.

    - Added acks that were given to v2.

v2: - Replaced standalone power-off call chain demo-API with the combined
      power-off+restart API because this is what drivers want. It's a more
      comprehensive solution.

    - Converted multiple drivers and arch code to the new API. Suggested by
      Andy Shevchenko. I skimmed through the rest of drivers, verifying that
      new API suits them. The rest of the drivers will be converted once we
      will settle on the new API, otherwise will be too many patches here.

    - v2 API doesn't expose notifier to users and require handlers to
      have unique priority. Suggested by Guenter Roeck.

    - v2 API has power-off chaining disabled by default and require
      drivers to explicitly opt-in to the chaining. This preserves old
      behaviour for existing drivers once they are converted to the new
      API.

Dmitry Osipenko (21):
  notifier: Add blocking_notifier_call_chain_is_empty()
  notifier: Add atomic/blocking_notifier_chain_register_unique_prio()
  reboot: Print error message if restart handler has duplicated priority
  kernel: Add combined power-off+restart handler call chain API
  ARM: Use do_kernel_power_off()
  csky: Use do_kernel_power_off()
  riscv: Use do_kernel_power_off()
  arm64: Use do_kernel_power_off()
  parisc: Use do_kernel_power_off()
  xen/x86: Use do_kernel_power_off()
  powerpc: Use do_kernel_power_off()
  m68k: Switch to new sys-off handler API
  sh: Use do_kernel_power_off()
  x86: Use do_kernel_power_off()
  ia64: Use do_kernel_power_off()
  mips: Use do_kernel_power_off()
  nds32: Use do_kernel_power_off()
  memory: emif: Use kernel_can_power_off()
  ACPI: power: Switch to sys-off handler API
  regulator: pfuze100: Use devm_register_sys_off_handler()
  reboot: Remove pm_power_off_prepare()

 arch/arm/kernel/reboot.c               |   4 +-
 arch/arm64/kernel/process.c            |   3 +-
 arch/csky/kernel/power.c               |   6 +-
 arch/ia64/kernel/process.c             |   4 +-
 arch/m68k/emu/natfeat.c                |   3 +-
 arch/m68k/include/asm/machdep.h        |   1 -
 arch/m68k/kernel/process.c             |   5 +-
 arch/m68k/kernel/setup_mm.c            |   1 -
 arch/m68k/kernel/setup_no.c            |   1 -
 arch/m68k/mac/config.c                 |   4 +-
 arch/mips/kernel/reset.c               |   3 +-
 arch/nds32/kernel/process.c            |   3 +-
 arch/parisc/kernel/process.c           |   4 +-
 arch/powerpc/kernel/setup-common.c     |   4 +-
 arch/powerpc/xmon/xmon.c               |   3 +-
 arch/riscv/kernel/reset.c              |  12 +-
 arch/sh/kernel/reboot.c                |   3 +-
 arch/x86/kernel/reboot.c               |   4 +-
 arch/x86/xen/enlighten_pv.c            |   4 +-
 drivers/acpi/sleep.c                   |  25 +-
 drivers/memory/emif.c                  |   2 +-
 drivers/regulator/pfuze100-regulator.c |  38 +-
 include/linux/notifier.h               |   7 +
 include/linux/pm.h                     |   1 -
 include/linux/reboot.h                 | 265 +++++++++++-
 kernel/notifier.c                      | 100 ++++-
 kernel/power/hibernate.c               |   2 +-
 kernel/reboot.c                        | 574 ++++++++++++++++++++++++-
 28 files changed, 968 insertions(+), 118 deletions(-)

-- 
2.33.1

[PATCH v5 00/21] Introduce power-off+restart call chain API

[Dmitry Osipenko]

Problem
-------

SoC devices require power-off call chaining functionality from kernel.
We have a widely used restart chaining provided by restart notifier API,
but nothing for power-off.

Solution
--------

Introduce new API that provides both restart and power-off call chains.

Why combine restart with power-off? Because drivers often do both.
More practical to have API that provides both under the same roof.

The new API is designed with simplicity and extensibility in mind.
It's built upon the existing restart and reboot APIs. The simplicity
is in new helper functions that are convenient for drivers. The
extensibility is in the design that doesn't hardcode callback
arguments, making easy to add new parameters and remove old.

This is a third attempt to introduce the new API. First was made by
Guenter Roeck back in 2014, second was made by Thierry Reding in 2017.
In fact the work didn't stop and recently arm_pm_restart() was removed
from v5.14 kernel, which was a part of preparatory work started by
Guenter Roeck. I took into account experience and ideas from the
previous attempts, extended and polished them.

Adoption plan
-------------

This patchset introduces the new API. It also converts multiple drivers
and arch code to the new API to demonstrate how it all looks in practice.

The plan is:

1. Merge new API (patches 1-8). This API will co-exist with the old APIs.

2. Convert arch code to do_kernel_power_off() (patches 9-21).

3. Convert drivers and platform code to the new API.

4. Remove obsolete pm_power_off and pm_power_off_prepare variables.

5. Make restart-notifier API private to kernel/reboot.c once no users left.

6. Make uniqueness of the handlers' priority a mandatory requirement.

It's fully implemented here:

[1] https://github.com/grate-driver/linux/commits/sys-off-handler

For now I'm sending only the first 25 base patches out of ~180. It's
preferable to squash 1-2, partially 3 and 4 points of the plan into a
single patchset to ease and speed up applying of the rest of the patches.
Majority of drivers and platform patches depend on the base, hence they
will come later (and per subsystem), once base will land.

All [1] patches are compile-tested. Tegra and x86 ACPI patches are tested
on hardware. The remaining should be covered by unit tests (unpublished).

Results
-------

1. Devices can be powered off properly.

2. Global variables are removed from drivers.

3. Global pm_power_off and pm_power_off_prepare callback variables are
removed once all users are converted to the new API. The latter callback
is removed by patch #25 of this series.

4. Ambiguous call chain ordering is prohibited. See patch #5 which adds
verification of restart handlers priorities, ensuring that they are unique.

Changelog:

v5: - Dropped patches which cleaned up notifier/reboot headers, as was
      requested by Rafael Wysocki.

    - Dropped WARN_ON() from the code, as was requested by Rafael Wysocki.
      Replaced it with pr_err() appropriately.

    - Dropped *_notifier_has_unique_priority() functions and added
      *_notifier_chain_register_unique_prio() instead, as was suggested
      by Michał Mirosław and Rafael Wysocki.

    - Dropped export of blocking_notifier_call_chain_is_empty() symbol,
      as was suggested by Rafael Wysocki.

    - Michał Mirosław suggested that will be better to split up patch
      that adds the new API to ease reviewing, but Rafael Wysocki asked
      not add more patches, so I kept it as a single patch.

    - Added temporary "weak" stub for pm_power_off() which fixes linkage
      failure once symbol is removed from arch/* code. Previously I missed
      this problem because was only compile-testing object files.

v4: - Made a very minor improvement to doc comments, clarifying couple
      default values.

    - Corrected list of emails recipient by adding Linus, Sebastian,
      Philipp and more NDS people. Removed bouncing emails.

    - Added acks that were given to v3.

v3: - Renamed power_handler to sys_off_handler as was suggested by
      Rafael Wysocki.

    - Improved doc-comments as was suggested by Rafael Wysocki. Added more
      doc-comments.

    - Implemented full set of 180 patches which convert whole kernel in
      accordance to the plan, see link [1] above. Slightly adjusted API to
      better suit for the remaining converted drivers.

      * Added unregister_sys_off_handler() that is handy for a couple old
        platform drivers.

      * Dropped devm_register_trivial_restart_handler(), 'simple' variant
        is enough to have.

    - Improved "Add atomic/blocking_notifier_has_unique_priority()" patch,
      as was suggested by Andy Shevchenko. Also replaced down_write() with
      down_read() and factored out common notifier_has_unique_priority().

    - Added stop_chain field to struct restart_data and reboot_prep_data
      after discovering couple drivers wanting that feature.

    - Added acks that were given to v2.

v2: - Replaced standalone power-off call chain demo-API with the combined
      power-off+restart API because this is what drivers want. It's a more
      comprehensive solution.

    - Converted multiple drivers and arch code to the new API. Suggested by
      Andy Shevchenko. I skimmed through the rest of drivers, verifying that
      new API suits them. The rest of the drivers will be converted once we
      will settle on the new API, otherwise will be too many patches here.

    - v2 API doesn't expose notifier to users and require handlers to
      have unique priority. Suggested by Guenter Roeck.

    - v2 API has power-off chaining disabled by default and require
      drivers to explicitly opt-in to the chaining. This preserves old
      behaviour for existing drivers once they are converted to the new
      API.

Dmitry Osipenko (21):
  notifier: Add blocking_notifier_call_chain_is_empty()
  notifier: Add atomic/blocking_notifier_chain_register_unique_prio()
  reboot: Print error message if restart handler has duplicated priority
  kernel: Add combined power-off+restart handler call chain API
  ARM: Use do_kernel_power_off()
  csky: Use do_kernel_power_off()
  riscv: Use do_kernel_power_off()
  arm64: Use do_kernel_power_off()
  parisc: Use do_kernel_power_off()
  xen/x86: Use do_kernel_power_off()
  powerpc: Use do_kernel_power_off()
  m68k: Switch to new sys-off handler API
  sh: Use do_kernel_power_off()
  x86: Use do_kernel_power_off()
  ia64: Use do_kernel_power_off()
  mips: Use do_kernel_power_off()
  nds32: Use do_kernel_power_off()
  memory: emif: Use kernel_can_power_off()
  ACPI: power: Switch to sys-off handler API
  regulator: pfuze100: Use devm_register_sys_off_handler()
  reboot: Remove pm_power_off_prepare()

 arch/arm/kernel/reboot.c               |   4 +-
 arch/arm64/kernel/process.c            |   3 +-
 arch/csky/kernel/power.c               |   6 +-
 arch/ia64/kernel/process.c             |   4 +-
 arch/m68k/emu/natfeat.c                |   3 +-
 arch/m68k/include/asm/machdep.h        |   1 -
 arch/m68k/kernel/process.c             |   5 +-
 arch/m68k/kernel/setup_mm.c            |   1 -
 arch/m68k/kernel/setup_no.c            |   1 -
 arch/m68k/mac/config.c                 |   4 +-
 arch/mips/kernel/reset.c               |   3 +-
 arch/nds32/kernel/process.c            |   3 +-
 arch/parisc/kernel/process.c           |   4 +-
 arch/powerpc/kernel/setup-common.c     |   4 +-
 arch/powerpc/xmon/xmon.c               |   3 +-
 arch/riscv/kernel/reset.c              |  12 +-
 arch/sh/kernel/reboot.c                |   3 +-
 arch/x86/kernel/reboot.c               |   4 +-
 arch/x86/xen/enlighten_pv.c            |   4 +-
 drivers/acpi/sleep.c                   |  25 +-
 drivers/memory/emif.c                  |   2 +-
 drivers/regulator/pfuze100-regulator.c |  38 +-
 include/linux/notifier.h               |   7 +
 include/linux/pm.h                     |   1 -
 include/linux/reboot.h                 | 265 +++++++++++-
 kernel/notifier.c                      | 100 ++++-
 kernel/power/hibernate.c               |   2 +-
 kernel/reboot.c                        | 574 ++++++++++++++++++++++++-
 28 files changed, 968 insertions(+), 118 deletions(-)

-- 
2.33.1

[PATCH v5 01/21] notifier: Add blocking_notifier_call_chain_is_empty()

[Dmitry Osipenko]

Add blocking_notifier_call_chain_is_empty() that returns true if call
chain is empty.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/notifier.h |  2 ++
 kernel/notifier.c        | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 87069b8459af..d4717bc0ab85 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -173,6 +173,8 @@ extern int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh
 extern int raw_notifier_call_chain_robust(struct raw_notifier_head *nh,
 		unsigned long val_up, unsigned long val_down, void *v);
 
+extern bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh);
+
 #define NOTIFY_DONE		0x0000		/* Don't care */
 #define NOTIFY_OK		0x0001		/* Suits me */
 #define NOTIFY_STOP_MASK	0x8000		/* Don't call further */
diff --git a/kernel/notifier.c b/kernel/notifier.c
index b8251dc0bc0f..e30d24ee88e9 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -322,6 +322,19 @@ int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
 }
 EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
 
+/**
+ *	blocking_notifier_call_chain_is_empty - Check whether notifier chain is empty
+ *	@nh: Pointer to head of the blocking notifier chain
+ *
+ *	Checks whether notifier chain is empty.
+ *
+ *	Returns true is notifier chain is empty, false otherwise.
+ */
+bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh)
+{
+	return !rcu_access_pointer(nh->head);
+}
+
 /*
  *	Raw notifier chain routines.  There is no protection;
  *	the caller must provide it.  Use at your own risk!
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 01/21] notifier: Add blocking_notifier_call_chain_is_empty()

[Dmitry Osipenko]

Add blocking_notifier_call_chain_is_empty() that returns true if call
chain is empty.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/notifier.h |  2 ++
 kernel/notifier.c        | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 87069b8459af..d4717bc0ab85 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -173,6 +173,8 @@ extern int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh
 extern int raw_notifier_call_chain_robust(struct raw_notifier_head *nh,
 		unsigned long val_up, unsigned long val_down, void *v);
 
+extern bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh);
+
 #define NOTIFY_DONE		0x0000		/* Don't care */
 #define NOTIFY_OK		0x0001		/* Suits me */
 #define NOTIFY_STOP_MASK	0x8000		/* Don't call further */
diff --git a/kernel/notifier.c b/kernel/notifier.c
index b8251dc0bc0f..e30d24ee88e9 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -322,6 +322,19 @@ int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
 }
 EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
 
+/**
+ *	blocking_notifier_call_chain_is_empty - Check whether notifier chain is empty
+ *	@nh: Pointer to head of the blocking notifier chain
+ *
+ *	Checks whether notifier chain is empty.
+ *
+ *	Returns true is notifier chain is empty, false otherwise.
+ */
+bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh)
+{
+	return !rcu_access_pointer(nh->head);
+}
+
 /*
  *	Raw notifier chain routines.  There is no protection;
  *	the caller must provide it.  Use at your own risk!
-- 
2.33.1

[PATCH v5 01/21] notifier: Add blocking_notifier_call_chain_is_empty()

[Dmitry Osipenko]

Add blocking_notifier_call_chain_is_empty() that returns true if call
chain is empty.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/notifier.h |  2 ++
 kernel/notifier.c        | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 87069b8459af..d4717bc0ab85 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -173,6 +173,8 @@ extern int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh
 extern int raw_notifier_call_chain_robust(struct raw_notifier_head *nh,
 		unsigned long val_up, unsigned long val_down, void *v);
 
+extern bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh);
+
 #define NOTIFY_DONE		0x0000		/* Don't care */
 #define NOTIFY_OK		0x0001		/* Suits me */
 #define NOTIFY_STOP_MASK	0x8000		/* Don't call further */
diff --git a/kernel/notifier.c b/kernel/notifier.c
index b8251dc0bc0f..e30d24ee88e9 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -322,6 +322,19 @@ int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
 }
 EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
 
+/**
+ *	blocking_notifier_call_chain_is_empty - Check whether notifier chain is empty
+ *	@nh: Pointer to head of the blocking notifier chain
+ *
+ *	Checks whether notifier chain is empty.
+ *
+ *	Returns true is notifier chain is empty, false otherwise.
+ */
+bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh)
+{
+	return !rcu_access_pointer(nh->head);
+}
+
 /*
  *	Raw notifier chain routines.  There is no protection;
  *	the caller must provide it.  Use at your own risk!
-- 
2.33.1

[PATCH v5 01/21] notifier: Add blocking_notifier_call_chain_is_empty()

[Dmitry Osipenko]

Add blocking_notifier_call_chain_is_empty() that returns true if call
chain is empty.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/notifier.h |  2 ++
 kernel/notifier.c        | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index 87069b8459af..d4717bc0ab85 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -173,6 +173,8 @@ extern int blocking_notifier_call_chain_robust(struct blocking_notifier_head *nh
 extern int raw_notifier_call_chain_robust(struct raw_notifier_head *nh,
 		unsigned long val_up, unsigned long val_down, void *v);
 
+extern bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh);
+
 #define NOTIFY_DONE		0x0000		/* Don't care */
 #define NOTIFY_OK		0x0001		/* Suits me */
 #define NOTIFY_STOP_MASK	0x8000		/* Don't call further */
diff --git a/kernel/notifier.c b/kernel/notifier.c
index b8251dc0bc0f..e30d24ee88e9 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -322,6 +322,19 @@ int blocking_notifier_call_chain(struct blocking_notifier_head *nh,
 }
 EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
 
+/**
+ *	blocking_notifier_call_chain_is_empty - Check whether notifier chain is empty
+ *	@nh: Pointer to head of the blocking notifier chain
+ *
+ *	Checks whether notifier chain is empty.
+ *
+ *	Returns true is notifier chain is empty, false otherwise.
+ */
+bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh)
+{
+	return !rcu_access_pointer(nh->head);
+}
+
 /*
  *	Raw notifier chain routines.  There is no protection;
  *	the caller must provide it.  Use at your own risk!
-- 
2.33.1

[PATCH v5 02/21] notifier: Add atomic/blocking_notifier_chain_register_unique_prio()

[Dmitry Osipenko]

Add variant of atomic/blocking_notifier_chain_register() functions that
doesn't allow to register notifier using a duplicated priority. The -EBUSY
error code is returned in this case by the new API functions.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/notifier.h |  5 +++
 kernel/notifier.c        | 87 +++++++++++++++++++++++++++++++---------
 2 files changed, 73 insertions(+), 19 deletions(-)

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index d4717bc0ab85..ccce26197dd2 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -150,6 +150,11 @@ extern int raw_notifier_chain_register(struct raw_notifier_head *nh,
 extern int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
 		struct notifier_block *nb);
 
+extern int atomic_notifier_chain_register_unique_prio(
+		struct atomic_notifier_head *nh, struct notifier_block *nb);
+extern int blocking_notifier_chain_register_unique_prio(
+		struct blocking_notifier_head *nh, struct notifier_block *nb);
+
 extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
 		struct notifier_block *nb);
 extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
diff --git a/kernel/notifier.c b/kernel/notifier.c
index e30d24ee88e9..77e5112ff05b 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -20,7 +20,7 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
  */
 
 static int notifier_chain_register(struct notifier_block **nl,
-		struct notifier_block *n)
+		struct notifier_block *n, bool unique_priority)
 {
 	while ((*nl) != NULL) {
 		if (unlikely((*nl) == n)) {
@@ -29,6 +29,8 @@ static int notifier_chain_register(struct notifier_block **nl,
 		}
 		if (n->priority > (*nl)->priority)
 			break;
+		if (n->priority == (*nl)->priority && unique_priority)
+			return -EBUSY;
 		nl = &((*nl)->next);
 	}
 	n->next = *nl;
@@ -143,12 +145,35 @@ int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
 	int ret;
 
 	spin_lock_irqsave(&nh->lock, flags);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, false);
 	spin_unlock_irqrestore(&nh->lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
 
+/**
+ *	atomic_notifier_chain_register_unique_prio - Add notifier to an atomic notifier chain
+ *	@nh: Pointer to head of the atomic notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an atomic notifier chain if there is no other
+ *	notifier registered using the same priority.
+ *
+ *	Returns zero on success, -EBUSY otherwise.
+ */
+int atomic_notifier_chain_register_unique_prio(struct atomic_notifier_head *nh,
+					       struct notifier_block *n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_register(&nh->head, n, true);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_chain_register_unique_prio);
+
 /**
  *	atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain
  *	@nh: Pointer to head of the atomic notifier chain
@@ -208,18 +233,9 @@ NOKPROBE_SYMBOL(atomic_notifier_call_chain);
  *	synchronized by an rwsem.
  */
 
-/**
- *	blocking_notifier_chain_register - Add notifier to a blocking notifier chain
- *	@nh: Pointer to head of the blocking notifier chain
- *	@n: New entry in notifier chain
- *
- *	Adds a notifier to a blocking notifier chain.
- *	Must be called in process context.
- *
- *	Currently always returns zero.
- */
-int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
-		struct notifier_block *n)
+static int __blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+					      struct notifier_block *n,
+					      bool unique_priority)
 {
 	int ret;
 
@@ -229,15 +245,48 @@ int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
 	 * such times we must not call down_write().
 	 */
 	if (unlikely(system_state == SYSTEM_BOOTING))
-		return notifier_chain_register(&nh->head, n);
+		return notifier_chain_register(&nh->head, n, unique_priority);
 
 	down_write(&nh->rwsem);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, unique_priority);
 	up_write(&nh->rwsem);
 	return ret;
 }
+
+/**
+ *	blocking_notifier_chain_register - Add notifier to a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to a blocking notifier chain.
+ *	Must be called in process context.
+ *
+ *	Currently always returns zero.
+ */
+int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+		struct notifier_block *n)
+{
+	return __blocking_notifier_chain_register(nh, n, false);
+}
 EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);
 
+/**
+ *	blocking_notifier_chain_register_unique_prio - Add notifier to a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an blocking notifier chain if there is no other
+ *	notifier registered using the same priority.
+ *
+ *	Returns zero on success, -EBUSY otherwise.
+ */
+int blocking_notifier_chain_register_unique_prio(struct blocking_notifier_head *nh,
+						 struct notifier_block *n)
+{
+	return __blocking_notifier_chain_register(nh, n, true);
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_chain_register_unique_prio);
+
 /**
  *	blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
  *	@nh: Pointer to head of the blocking notifier chain
@@ -353,7 +402,7 @@ bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh)
 int raw_notifier_chain_register(struct raw_notifier_head *nh,
 		struct notifier_block *n)
 {
-	return notifier_chain_register(&nh->head, n);
+	return notifier_chain_register(&nh->head, n, false);
 }
 EXPORT_SYMBOL_GPL(raw_notifier_chain_register);
 
@@ -432,10 +481,10 @@ int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
 	 * such times we must not call mutex_lock().
 	 */
 	if (unlikely(system_state == SYSTEM_BOOTING))
-		return notifier_chain_register(&nh->head, n);
+		return notifier_chain_register(&nh->head, n, false);
 
 	mutex_lock(&nh->mutex);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, false);
 	mutex_unlock(&nh->mutex);
 	return ret;
 }
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 02/21] notifier: Add atomic/blocking_notifier_chain_register_unique_prio()

[Dmitry Osipenko]

Add variant of atomic/blocking_notifier_chain_register() functions that
doesn't allow to register notifier using a duplicated priority. The -EBUSY
error code is returned in this case by the new API functions.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/notifier.h |  5 +++
 kernel/notifier.c        | 87 +++++++++++++++++++++++++++++++---------
 2 files changed, 73 insertions(+), 19 deletions(-)

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index d4717bc0ab85..ccce26197dd2 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -150,6 +150,11 @@ extern int raw_notifier_chain_register(struct raw_notifier_head *nh,
 extern int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
 		struct notifier_block *nb);
 
+extern int atomic_notifier_chain_register_unique_prio(
+		struct atomic_notifier_head *nh, struct notifier_block *nb);
+extern int blocking_notifier_chain_register_unique_prio(
+		struct blocking_notifier_head *nh, struct notifier_block *nb);
+
 extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
 		struct notifier_block *nb);
 extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
diff --git a/kernel/notifier.c b/kernel/notifier.c
index e30d24ee88e9..77e5112ff05b 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -20,7 +20,7 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
  */
 
 static int notifier_chain_register(struct notifier_block **nl,
-		struct notifier_block *n)
+		struct notifier_block *n, bool unique_priority)
 {
 	while ((*nl) != NULL) {
 		if (unlikely((*nl) == n)) {
@@ -29,6 +29,8 @@ static int notifier_chain_register(struct notifier_block **nl,
 		}
 		if (n->priority > (*nl)->priority)
 			break;
+		if (n->priority == (*nl)->priority && unique_priority)
+			return -EBUSY;
 		nl = &((*nl)->next);
 	}
 	n->next = *nl;
@@ -143,12 +145,35 @@ int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
 	int ret;
 
 	spin_lock_irqsave(&nh->lock, flags);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, false);
 	spin_unlock_irqrestore(&nh->lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
 
+/**
+ *	atomic_notifier_chain_register_unique_prio - Add notifier to an atomic notifier chain
+ *	@nh: Pointer to head of the atomic notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an atomic notifier chain if there is no other
+ *	notifier registered using the same priority.
+ *
+ *	Returns zero on success, -EBUSY otherwise.
+ */
+int atomic_notifier_chain_register_unique_prio(struct atomic_notifier_head *nh,
+					       struct notifier_block *n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_register(&nh->head, n, true);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_chain_register_unique_prio);
+
 /**
  *	atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain
  *	@nh: Pointer to head of the atomic notifier chain
@@ -208,18 +233,9 @@ NOKPROBE_SYMBOL(atomic_notifier_call_chain);
  *	synchronized by an rwsem.
  */
 
-/**
- *	blocking_notifier_chain_register - Add notifier to a blocking notifier chain
- *	@nh: Pointer to head of the blocking notifier chain
- *	@n: New entry in notifier chain
- *
- *	Adds a notifier to a blocking notifier chain.
- *	Must be called in process context.
- *
- *	Currently always returns zero.
- */
-int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
-		struct notifier_block *n)
+static int __blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+					      struct notifier_block *n,
+					      bool unique_priority)
 {
 	int ret;
 
@@ -229,15 +245,48 @@ int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
 	 * such times we must not call down_write().
 	 */
 	if (unlikely(system_state == SYSTEM_BOOTING))
-		return notifier_chain_register(&nh->head, n);
+		return notifier_chain_register(&nh->head, n, unique_priority);
 
 	down_write(&nh->rwsem);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, unique_priority);
 	up_write(&nh->rwsem);
 	return ret;
 }
+
+/**
+ *	blocking_notifier_chain_register - Add notifier to a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to a blocking notifier chain.
+ *	Must be called in process context.
+ *
+ *	Currently always returns zero.
+ */
+int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+		struct notifier_block *n)
+{
+	return __blocking_notifier_chain_register(nh, n, false);
+}
 EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);
 
+/**
+ *	blocking_notifier_chain_register_unique_prio - Add notifier to a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an blocking notifier chain if there is no other
+ *	notifier registered using the same priority.
+ *
+ *	Returns zero on success, -EBUSY otherwise.
+ */
+int blocking_notifier_chain_register_unique_prio(struct blocking_notifier_head *nh,
+						 struct notifier_block *n)
+{
+	return __blocking_notifier_chain_register(nh, n, true);
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_chain_register_unique_prio);
+
 /**
  *	blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
  *	@nh: Pointer to head of the blocking notifier chain
@@ -353,7 +402,7 @@ bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh)
 int raw_notifier_chain_register(struct raw_notifier_head *nh,
 		struct notifier_block *n)
 {
-	return notifier_chain_register(&nh->head, n);
+	return notifier_chain_register(&nh->head, n, false);
 }
 EXPORT_SYMBOL_GPL(raw_notifier_chain_register);
 
@@ -432,10 +481,10 @@ int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
 	 * such times we must not call mutex_lock().
 	 */
 	if (unlikely(system_state == SYSTEM_BOOTING))
-		return notifier_chain_register(&nh->head, n);
+		return notifier_chain_register(&nh->head, n, false);
 
 	mutex_lock(&nh->mutex);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, false);
 	mutex_unlock(&nh->mutex);
 	return ret;
 }
-- 
2.33.1

[PATCH v5 02/21] notifier: Add atomic/blocking_notifier_chain_register_unique_prio()

[Dmitry Osipenko]

Add variant of atomic/blocking_notifier_chain_register() functions that
doesn't allow to register notifier using a duplicated priority. The -EBUSY
error code is returned in this case by the new API functions.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/notifier.h |  5 +++
 kernel/notifier.c        | 87 +++++++++++++++++++++++++++++++---------
 2 files changed, 73 insertions(+), 19 deletions(-)

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index d4717bc0ab85..ccce26197dd2 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -150,6 +150,11 @@ extern int raw_notifier_chain_register(struct raw_notifier_head *nh,
 extern int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
 		struct notifier_block *nb);
 
+extern int atomic_notifier_chain_register_unique_prio(
+		struct atomic_notifier_head *nh, struct notifier_block *nb);
+extern int blocking_notifier_chain_register_unique_prio(
+		struct blocking_notifier_head *nh, struct notifier_block *nb);
+
 extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
 		struct notifier_block *nb);
 extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
diff --git a/kernel/notifier.c b/kernel/notifier.c
index e30d24ee88e9..77e5112ff05b 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -20,7 +20,7 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
  */
 
 static int notifier_chain_register(struct notifier_block **nl,
-		struct notifier_block *n)
+		struct notifier_block *n, bool unique_priority)
 {
 	while ((*nl) != NULL) {
 		if (unlikely((*nl) == n)) {
@@ -29,6 +29,8 @@ static int notifier_chain_register(struct notifier_block **nl,
 		}
 		if (n->priority > (*nl)->priority)
 			break;
+		if (n->priority == (*nl)->priority && unique_priority)
+			return -EBUSY;
 		nl = &((*nl)->next);
 	}
 	n->next = *nl;
@@ -143,12 +145,35 @@ int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
 	int ret;
 
 	spin_lock_irqsave(&nh->lock, flags);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, false);
 	spin_unlock_irqrestore(&nh->lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
 
+/**
+ *	atomic_notifier_chain_register_unique_prio - Add notifier to an atomic notifier chain
+ *	@nh: Pointer to head of the atomic notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an atomic notifier chain if there is no other
+ *	notifier registered using the same priority.
+ *
+ *	Returns zero on success, -EBUSY otherwise.
+ */
+int atomic_notifier_chain_register_unique_prio(struct atomic_notifier_head *nh,
+					       struct notifier_block *n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_register(&nh->head, n, true);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_chain_register_unique_prio);
+
 /**
  *	atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain
  *	@nh: Pointer to head of the atomic notifier chain
@@ -208,18 +233,9 @@ NOKPROBE_SYMBOL(atomic_notifier_call_chain);
  *	synchronized by an rwsem.
  */
 
-/**
- *	blocking_notifier_chain_register - Add notifier to a blocking notifier chain
- *	@nh: Pointer to head of the blocking notifier chain
- *	@n: New entry in notifier chain
- *
- *	Adds a notifier to a blocking notifier chain.
- *	Must be called in process context.
- *
- *	Currently always returns zero.
- */
-int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
-		struct notifier_block *n)
+static int __blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+					      struct notifier_block *n,
+					      bool unique_priority)
 {
 	int ret;
 
@@ -229,15 +245,48 @@ int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
 	 * such times we must not call down_write().
 	 */
 	if (unlikely(system_state == SYSTEM_BOOTING))
-		return notifier_chain_register(&nh->head, n);
+		return notifier_chain_register(&nh->head, n, unique_priority);
 
 	down_write(&nh->rwsem);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, unique_priority);
 	up_write(&nh->rwsem);
 	return ret;
 }
+
+/**
+ *	blocking_notifier_chain_register - Add notifier to a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to a blocking notifier chain.
+ *	Must be called in process context.
+ *
+ *	Currently always returns zero.
+ */
+int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+		struct notifier_block *n)
+{
+	return __blocking_notifier_chain_register(nh, n, false);
+}
 EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);
 
+/**
+ *	blocking_notifier_chain_register_unique_prio - Add notifier to a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an blocking notifier chain if there is no other
+ *	notifier registered using the same priority.
+ *
+ *	Returns zero on success, -EBUSY otherwise.
+ */
+int blocking_notifier_chain_register_unique_prio(struct blocking_notifier_head *nh,
+						 struct notifier_block *n)
+{
+	return __blocking_notifier_chain_register(nh, n, true);
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_chain_register_unique_prio);
+
 /**
  *	blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
  *	@nh: Pointer to head of the blocking notifier chain
@@ -353,7 +402,7 @@ bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh)
 int raw_notifier_chain_register(struct raw_notifier_head *nh,
 		struct notifier_block *n)
 {
-	return notifier_chain_register(&nh->head, n);
+	return notifier_chain_register(&nh->head, n, false);
 }
 EXPORT_SYMBOL_GPL(raw_notifier_chain_register);
 
@@ -432,10 +481,10 @@ int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
 	 * such times we must not call mutex_lock().
 	 */
 	if (unlikely(system_state == SYSTEM_BOOTING))
-		return notifier_chain_register(&nh->head, n);
+		return notifier_chain_register(&nh->head, n, false);
 
 	mutex_lock(&nh->mutex);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, false);
 	mutex_unlock(&nh->mutex);
 	return ret;
 }
-- 
2.33.1

[PATCH v5 02/21] notifier: Add atomic/blocking_notifier_chain_register_unique_prio()

[Dmitry Osipenko]

Add variant of atomic/blocking_notifier_chain_register() functions that
doesn't allow to register notifier using a duplicated priority. The -EBUSY
error code is returned in this case by the new API functions.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/notifier.h |  5 +++
 kernel/notifier.c        | 87 +++++++++++++++++++++++++++++++---------
 2 files changed, 73 insertions(+), 19 deletions(-)

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index d4717bc0ab85..ccce26197dd2 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -150,6 +150,11 @@ extern int raw_notifier_chain_register(struct raw_notifier_head *nh,
 extern int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
 		struct notifier_block *nb);
 
+extern int atomic_notifier_chain_register_unique_prio(
+		struct atomic_notifier_head *nh, struct notifier_block *nb);
+extern int blocking_notifier_chain_register_unique_prio(
+		struct blocking_notifier_head *nh, struct notifier_block *nb);
+
 extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh,
 		struct notifier_block *nb);
 extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
diff --git a/kernel/notifier.c b/kernel/notifier.c
index e30d24ee88e9..77e5112ff05b 100644
--- a/kernel/notifier.c
+++ b/kernel/notifier.c
@@ -20,7 +20,7 @@ BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);
  */
 
 static int notifier_chain_register(struct notifier_block **nl,
-		struct notifier_block *n)
+		struct notifier_block *n, bool unique_priority)
 {
 	while ((*nl) != NULL) {
 		if (unlikely((*nl) = n)) {
@@ -29,6 +29,8 @@ static int notifier_chain_register(struct notifier_block **nl,
 		}
 		if (n->priority > (*nl)->priority)
 			break;
+		if (n->priority = (*nl)->priority && unique_priority)
+			return -EBUSY;
 		nl = &((*nl)->next);
 	}
 	n->next = *nl;
@@ -143,12 +145,35 @@ int atomic_notifier_chain_register(struct atomic_notifier_head *nh,
 	int ret;
 
 	spin_lock_irqsave(&nh->lock, flags);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, false);
 	spin_unlock_irqrestore(&nh->lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(atomic_notifier_chain_register);
 
+/**
+ *	atomic_notifier_chain_register_unique_prio - Add notifier to an atomic notifier chain
+ *	@nh: Pointer to head of the atomic notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an atomic notifier chain if there is no other
+ *	notifier registered using the same priority.
+ *
+ *	Returns zero on success, -EBUSY otherwise.
+ */
+int atomic_notifier_chain_register_unique_prio(struct atomic_notifier_head *nh,
+					       struct notifier_block *n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_register(&nh->head, n, true);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(atomic_notifier_chain_register_unique_prio);
+
 /**
  *	atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain
  *	@nh: Pointer to head of the atomic notifier chain
@@ -208,18 +233,9 @@ NOKPROBE_SYMBOL(atomic_notifier_call_chain);
  *	synchronized by an rwsem.
  */
 
-/**
- *	blocking_notifier_chain_register - Add notifier to a blocking notifier chain
- *	@nh: Pointer to head of the blocking notifier chain
- *	@n: New entry in notifier chain
- *
- *	Adds a notifier to a blocking notifier chain.
- *	Must be called in process context.
- *
- *	Currently always returns zero.
- */
-int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
-		struct notifier_block *n)
+static int __blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+					      struct notifier_block *n,
+					      bool unique_priority)
 {
 	int ret;
 
@@ -229,15 +245,48 @@ int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
 	 * such times we must not call down_write().
 	 */
 	if (unlikely(system_state = SYSTEM_BOOTING))
-		return notifier_chain_register(&nh->head, n);
+		return notifier_chain_register(&nh->head, n, unique_priority);
 
 	down_write(&nh->rwsem);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, unique_priority);
 	up_write(&nh->rwsem);
 	return ret;
 }
+
+/**
+ *	blocking_notifier_chain_register - Add notifier to a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to a blocking notifier chain.
+ *	Must be called in process context.
+ *
+ *	Currently always returns zero.
+ */
+int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
+		struct notifier_block *n)
+{
+	return __blocking_notifier_chain_register(nh, n, false);
+}
 EXPORT_SYMBOL_GPL(blocking_notifier_chain_register);
 
+/**
+ *	blocking_notifier_chain_register_unique_prio - Add notifier to a blocking notifier chain
+ *	@nh: Pointer to head of the blocking notifier chain
+ *	@n: New entry in notifier chain
+ *
+ *	Adds a notifier to an blocking notifier chain if there is no other
+ *	notifier registered using the same priority.
+ *
+ *	Returns zero on success, -EBUSY otherwise.
+ */
+int blocking_notifier_chain_register_unique_prio(struct blocking_notifier_head *nh,
+						 struct notifier_block *n)
+{
+	return __blocking_notifier_chain_register(nh, n, true);
+}
+EXPORT_SYMBOL_GPL(blocking_notifier_chain_register_unique_prio);
+
 /**
  *	blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain
  *	@nh: Pointer to head of the blocking notifier chain
@@ -353,7 +402,7 @@ bool blocking_notifier_call_chain_is_empty(struct blocking_notifier_head *nh)
 int raw_notifier_chain_register(struct raw_notifier_head *nh,
 		struct notifier_block *n)
 {
-	return notifier_chain_register(&nh->head, n);
+	return notifier_chain_register(&nh->head, n, false);
 }
 EXPORT_SYMBOL_GPL(raw_notifier_chain_register);
 
@@ -432,10 +481,10 @@ int srcu_notifier_chain_register(struct srcu_notifier_head *nh,
 	 * such times we must not call mutex_lock().
 	 */
 	if (unlikely(system_state = SYSTEM_BOOTING))
-		return notifier_chain_register(&nh->head, n);
+		return notifier_chain_register(&nh->head, n, false);
 
 	mutex_lock(&nh->mutex);
-	ret = notifier_chain_register(&nh->head, n);
+	ret = notifier_chain_register(&nh->head, n, false);
 	mutex_unlock(&nh->mutex);
 	return ret;
 }
-- 
2.33.1

[PATCH v5 03/21] reboot: Print error message if restart handler has duplicated priority

[Dmitry Osipenko]

Add sanity check which ensures that there are no two restart handlers
registered using the same priority. This requirement will become mandatory
once all drivers will be converted to the new API and such errors will be
fixed.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 kernel/reboot.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/kernel/reboot.c b/kernel/reboot.c
index 6bcc5d6a6572..35f0cde641c1 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -182,6 +182,21 @@ static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
  */
 int register_restart_handler(struct notifier_block *nb)
 {
+	int ret;
+
+	ret = atomic_notifier_chain_register_unique_prio(&restart_handler_list, nb);
+	if (ret != -EBUSY)
+		return ret;
+
+	/*
+	 * Handler must have unique priority. Otherwise call order is
+	 * determined by registration order, which is unreliable.
+	 *
+	 * This requirement will become mandatory once all drivers
+	 * will be converted to use new sys-off API.
+	 */
+	pr_err("failed to register restart handler using unique priority\n");
+
 	return atomic_notifier_chain_register(&restart_handler_list, nb);
 }
 EXPORT_SYMBOL(register_restart_handler);
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 03/21] reboot: Print error message if restart handler has duplicated priority

[Dmitry Osipenko]

Add sanity check which ensures that there are no two restart handlers
registered using the same priority. This requirement will become mandatory
once all drivers will be converted to the new API and such errors will be
fixed.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 kernel/reboot.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/kernel/reboot.c b/kernel/reboot.c
index 6bcc5d6a6572..35f0cde641c1 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -182,6 +182,21 @@ static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
  */
 int register_restart_handler(struct notifier_block *nb)
 {
+	int ret;
+
+	ret = atomic_notifier_chain_register_unique_prio(&restart_handler_list, nb);
+	if (ret != -EBUSY)
+		return ret;
+
+	/*
+	 * Handler must have unique priority. Otherwise call order is
+	 * determined by registration order, which is unreliable.
+	 *
+	 * This requirement will become mandatory once all drivers
+	 * will be converted to use new sys-off API.
+	 */
+	pr_err("failed to register restart handler using unique priority\n");
+
 	return atomic_notifier_chain_register(&restart_handler_list, nb);
 }
 EXPORT_SYMBOL(register_restart_handler);
-- 
2.33.1

[PATCH v5 03/21] reboot: Print error message if restart handler has duplicated priority

[Dmitry Osipenko]

Add sanity check which ensures that there are no two restart handlers
registered using the same priority. This requirement will become mandatory
once all drivers will be converted to the new API and such errors will be
fixed.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 kernel/reboot.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/kernel/reboot.c b/kernel/reboot.c
index 6bcc5d6a6572..35f0cde641c1 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -182,6 +182,21 @@ static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
  */
 int register_restart_handler(struct notifier_block *nb)
 {
+	int ret;
+
+	ret = atomic_notifier_chain_register_unique_prio(&restart_handler_list, nb);
+	if (ret != -EBUSY)
+		return ret;
+
+	/*
+	 * Handler must have unique priority. Otherwise call order is
+	 * determined by registration order, which is unreliable.
+	 *
+	 * This requirement will become mandatory once all drivers
+	 * will be converted to use new sys-off API.
+	 */
+	pr_err("failed to register restart handler using unique priority\n");
+
 	return atomic_notifier_chain_register(&restart_handler_list, nb);
 }
 EXPORT_SYMBOL(register_restart_handler);
-- 
2.33.1

[PATCH v5 03/21] reboot: Print error message if restart handler has duplicated priority

[Dmitry Osipenko]

Add sanity check which ensures that there are no two restart handlers
registered using the same priority. This requirement will become mandatory
once all drivers will be converted to the new API and such errors will be
fixed.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 kernel/reboot.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/kernel/reboot.c b/kernel/reboot.c
index 6bcc5d6a6572..35f0cde641c1 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -182,6 +182,21 @@ static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
  */
 int register_restart_handler(struct notifier_block *nb)
 {
+	int ret;
+
+	ret = atomic_notifier_chain_register_unique_prio(&restart_handler_list, nb);
+	if (ret != -EBUSY)
+		return ret;
+
+	/*
+	 * Handler must have unique priority. Otherwise call order is
+	 * determined by registration order, which is unreliable.
+	 *
+	 * This requirement will become mandatory once all drivers
+	 * will be converted to use new sys-off API.
+	 */
+	pr_err("failed to register restart handler using unique priority\n");
+
 	return atomic_notifier_chain_register(&restart_handler_list, nb);
 }
 EXPORT_SYMBOL(register_restart_handler);
-- 
2.33.1

[PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

SoC platforms often have multiple ways of how to perform system's
power-off and restart operations. Meanwhile today's kernel is limited to
a single option. Add combined power-off+restart handler call chain API,
which is inspired by the restart API. The new API provides both power-off
and restart functionality.

The old pm_power_off method will be kept around till all users are
converted to the new API.

Current restart API will be replaced by the new unified API since
new API is its superset. The restart functionality of the sys-off handler
API is built upon the existing restart-notifier APIs.

In order to ease conversion to the new API, convenient helpers are added
for the common use-cases. They will reduce amount of boilerplate code and
remove global variables. These helpers preserve old behaviour for cases
where only one power-off handler is expected, this is what all existing
drivers want, and thus, they could be easily converted to the new API.
Users of the new API should explicitly enable power-off chaining by
setting corresponding flag of the power_handler structure.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/reboot.h   | 265 ++++++++++++++++++-
 kernel/power/hibernate.c |   2 +-
 kernel/reboot.c          | 556 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 815 insertions(+), 8 deletions(-)

diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index af907a3d68d1..c2fa8d63c129 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -8,10 +8,35 @@
 
 struct device;
 
-#define SYS_DOWN	0x0001	/* Notify of system down */
-#define SYS_RESTART	SYS_DOWN
-#define SYS_HALT	0x0002	/* Notify of system halt */
-#define SYS_POWER_OFF	0x0003	/* Notify of system power off */
+enum reboot_prepare_mode {
+	SYS_DOWN = 1,		/* Notify of system down */
+	SYS_RESTART = SYS_DOWN,
+	SYS_HALT,		/* Notify of system halt */
+	SYS_POWER_OFF,		/* Notify of system power off */
+};
+
+/*
+ * Standard restart priority levels. Intended to be set in the
+ * sys_off_handler.restart_priority field.
+ *
+ * Use `RESTART_PRIO_ABC +- prio` style for additional levels.
+ *
+ * RESTART_PRIO_RESERVED:	Falls back to RESTART_PRIO_DEFAULT.
+ *				Drivers may leave priority initialized
+ *				to zero, to auto-set it to the default level.
+ *
+ * RESTART_PRIO_LOW:		Use this for handler of last resort.
+ *
+ * RESTART_PRIO_DEFAULT:	Use this for default/generic handler.
+ *
+ * RESTART_PRIO_HIGH:		Use this if you have multiple handlers and
+ *				this handler has higher priority than the
+ *				default handler.
+ */
+#define RESTART_PRIO_RESERVED		0
+#define RESTART_PRIO_LOW		8
+#define RESTART_PRIO_DEFAULT		128
+#define RESTART_PRIO_HIGH		192
 
 enum reboot_mode {
 	REBOOT_UNDEFINED = -1,
@@ -49,6 +74,237 @@ extern int register_restart_handler(struct notifier_block *);
 extern int unregister_restart_handler(struct notifier_block *);
 extern void do_kernel_restart(char *cmd);
 
+/*
+ * System power-off and restart API.
+ */
+
+/*
+ * Standard power-off priority levels. Intended to be set in the
+ * sys_off_handler.power_off_priority field.
+ *
+ * Use `POWEROFF_PRIO_ABC +- prio` style for additional levels.
+ *
+ * POWEROFF_PRIO_RESERVED:	Falls back to POWEROFF_PRIO_DEFAULT.
+ *				Drivers may leave priority initialized
+ *				to zero, to auto-set it to the default level.
+ *
+ * POWEROFF_PRIO_PLATFORM:	Intended to be used by platform-level handler.
+ *				Has lowest priority since device drivers are
+ *				expected to take over platform handler which
+ *				doesn't allow further callback chaining.
+ *
+ * POWEROFF_PRIO_DEFAULT:	Use this for default/generic handler.
+ *
+ * POWEROFF_PRIO_FIRMWARE:	Use this if handler uses firmware call.
+ *				Has highest priority since firmware is expected
+ *				to know best how to power-off hardware properly.
+ */
+#define POWEROFF_PRIO_RESERVED		0
+#define POWEROFF_PRIO_PLATFORM		1
+#define POWEROFF_PRIO_DEFAULT		128
+#define POWEROFF_PRIO_HIGH		192
+#define POWEROFF_PRIO_FIRMWARE		224
+
+enum poweroff_mode {
+	POWEROFF_NORMAL = 0,
+	POWEROFF_PREPARE,
+};
+
+/**
+ * struct power_off_data - Power-off callback argument
+ *
+ * @cb_data: Callback data.
+ */
+struct power_off_data {
+	void *cb_data;
+};
+
+/**
+ * struct power_off_prep_data - Power-off preparation callback argument
+ *
+ * @cb_data: Callback data.
+ */
+struct power_off_prep_data {
+	void *cb_data;
+};
+
+/**
+ * struct restart_data - Restart callback argument
+ *
+ * @cb_data: Callback data.
+ * @cmd: Restart command string.
+ * @stop_chain: Further lower priority callbacks won't be executed if set to
+ *		true. Can be changed within callback. Default is false.
+ * @mode: Reboot mode ID.
+ */
+struct restart_data {
+	void *cb_data;
+	const char *cmd;
+	bool stop_chain;
+	enum reboot_mode mode;
+};
+
+/**
+ * struct reboot_prep_data - Reboot and shutdown preparation callback argument
+ *
+ * @cb_data: Callback data.
+ * @cmd: Restart command string.
+ * @stop_chain: Further lower priority callbacks won't be executed if set to
+ *		true. Can be changed within callback. Default is false.
+ * @mode: Preparation mode ID.
+ */
+struct reboot_prep_data {
+	void *cb_data;
+	const char *cmd;
+	bool stop_chain;
+	enum reboot_prepare_mode mode;
+};
+
+struct sys_off_handler_private_data {
+	struct notifier_block power_off_nb;
+	struct notifier_block restart_nb;
+	struct notifier_block reboot_nb;
+	void (*platform_power_off_cb)(void);
+	void (*simple_power_off_cb)(void *data);
+	void *simple_power_off_cb_data;
+	bool registered;
+};
+
+/**
+ * struct sys_off_handler - System power-off and restart handler
+ *
+ * @cb_data: Pointer to user's data.
+ *
+ * @power_off_cb: Callback that powers off this machine. Inactive if NULL.
+ *
+ * @power_off_prepare_cb: Power-off preparation callback. All power-off
+ * preparation callbacks are invoked after @reboot_prepare_cb and before
+ * @power_off_cb. Inactive if NULL.
+ *
+ * @power_off_priority: Power-off callback priority, must be unique.
+ * Zero value is reserved and auto-reassigned to POWEROFF_PRIO_DEFAULT.
+ * Inactive if @power_off_cb is NULL.
+ *
+ * @power_off_chaining_allowed: Set to false if callback's execution should
+ * stop when @power_off_cb fails to power off this machine. True if further
+ * lower priority power-off callback should be executed. False is default
+ * value.
+ *
+ * @restart_cb: Callback that reboots this machine. Inactive if NULL.
+ *
+ * @restart_priority: Restart callback priority, must be unique. Zero value
+ * is reserved and auto-reassigned to RESTART_PRIO_DEFAULT. Inactive if
+ * @restart_cb is NULL.
+ *
+ * @restart_chaining_disallowed: Set to true if callback's execution should
+ * stop when @restart_cb fails to restart this machine. False if further
+ * lower priority restart callback should be executed. False is default
+ * value.
+ *
+ * @reboot_prepare_cb: Reboot/shutdown preparation callback. All reboot
+ * preparation callbacks are invoked before @restart_cb or @power_off_cb,
+ * depending on the mode. It's registered with register_reboot_notifier().
+ * The point is to remove boilerplate code from drivers which use this
+ * callback in conjunction with the restart/power-off callbacks.
+ *
+ * @reboot_priority: Reboot/shutdown preparation callback priority, doesn't
+ * need to be unique. Zero is default value. Inactive if @reboot_prepare_cb
+ * is NULL.
+ *
+ * @priv: Internal data. Shouldn't be touched.
+ *
+ * Describes power-off and restart handlers which are invoked by kernel
+ * to power off or restart this machine. Supports prioritized chaining for
+ * both restart and power-off handlers.
+ *
+ * Struct sys_off_handler can be static. Members of this structure must not be
+ * altered while handler is registered.
+ *
+ * Fill the structure members and pass it to @register_sys_off_handler().
+ */
+struct sys_off_handler {
+	void *cb_data;
+
+	void (*power_off_cb)(struct power_off_data *data);
+	void (*power_off_prepare_cb)(struct power_off_prep_data *data);
+	int power_off_priority;
+	bool power_off_chaining_allowed;
+
+	void (*restart_cb)(struct restart_data *data);
+	int restart_priority;
+	bool restart_chaining_disallowed;
+
+	void (*reboot_prepare_cb)(struct reboot_prep_data *data);
+	int reboot_priority;
+
+	const struct sys_off_handler_private_data priv;
+};
+
+int register_sys_off_handler(struct sys_off_handler *handler);
+int unregister_sys_off_handler(struct sys_off_handler *handler);
+
+int devm_register_sys_off_handler(struct device *dev,
+				  struct sys_off_handler *handler);
+
+int devm_register_prioritized_power_off_handler(struct device *dev,
+						int priority,
+						void (*callback)(void *data),
+						void *cb_data);
+
+/**
+ *	devm_register_simple_power_off_handler - Register simple power-off callback
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed power-off callback with default priority.
+ *	It will be invoked as last step of the power-off sequence. Further
+ *	lower priority callbacks won't be executed if this @callback fails.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+static inline int
+devm_register_simple_power_off_handler(struct device *dev,
+				       void (*callback)(void *data),
+				       void *cb_data)
+{
+	return devm_register_prioritized_power_off_handler(dev,
+							   POWEROFF_PRIO_DEFAULT,
+							   callback, cb_data);
+}
+
+int register_platform_power_off(void (*power_off)(void));
+int unregister_platform_power_off(void (*power_off)(void));
+
+int devm_register_prioritized_restart_handler(struct device *dev,
+					      int priority,
+					      void (*callback)(struct restart_data *data),
+					      void *cb_data);
+
+/**
+ *	devm_register_simple_restart_handler - Register simple restart callback
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed restart callback with default priority.
+ *	It will be invoked as a part of the restart sequence. Further
+ *	lower priority callback will be executed if this @callback fails.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+static inline int
+devm_register_simple_restart_handler(struct device *dev,
+				     void (*callback)(struct restart_data *data),
+				     void *cb_data)
+{
+	return devm_register_prioritized_restart_handler(dev,
+							 RESTART_PRIO_DEFAULT,
+							 callback, cb_data);
+}
+
+void do_kernel_power_off(void);
+
 /*
  * Architecture-specific implementations of sys_reboot commands.
  */
@@ -70,6 +326,7 @@ extern void kernel_restart_prepare(char *cmd);
 extern void kernel_restart(char *cmd);
 extern void kernel_halt(void);
 extern void kernel_power_off(void);
+extern bool kernel_can_power_off(void);
 
 extern int C_A_D; /* for sysctl */
 void ctrl_alt_del(void);
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index e6af502c2fd7..aebbdd757fb9 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -666,7 +666,7 @@ static void power_down(void)
 		hibernation_platform_enter();
 		fallthrough;
 	case HIBERNATION_SHUTDOWN:
-		if (pm_power_off)
+		if (kernel_can_power_off())
 			kernel_power_off();
 		break;
 	}
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 35f0cde641c1..3085873a876f 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -296,6 +296,547 @@ void kernel_halt(void)
 }
 EXPORT_SYMBOL_GPL(kernel_halt);
 
+/*
+ *	Notifier list for kernel code which wants to be called
+ *	to power off the system.
+ */
+static BLOCKING_NOTIFIER_HEAD(power_off_handler_list);
+
+/*
+ * Temporary stub that prevents linkage failure while we're in process
+ * of removing all uses of legacy pm_power_off() around the kernel.
+ */
+void __weak (*pm_power_off)(void);
+
+static void dummy_pm_power_off(void)
+{
+	/* temporary stub until pm_power_off() is gone, see more below */
+}
+
+static struct notifier_block *pm_power_off_nb;
+
+/**
+ *	register_power_off_handler - Register function to be called to power off
+ *				     the system
+ *	@nb: Info about handler function to be called
+ *	@nb->priority:	Handler priority. Handlers should follow the
+ *			following guidelines for setting priorities.
+ *			0:	Reserved
+ *			1:	Power-off handler of last resort,
+ *				with limited power-off capabilities
+ *			128:	Default power-off handler; use if no other
+ *				power-off handler is expected to be available,
+ *				and/or if power-off functionality is
+ *				sufficient to power-off the entire system
+ *			255:	Highest priority power-off handler, will
+ *				preempt all other power-off handlers
+ *
+ *	Registers a function with code to be called to power off the
+ *	system.
+ *
+ *	Registered functions will be called as last step of the power-off
+ *	sequence.
+ *
+ *	Registered functions are expected to power off the system immediately.
+ *	If more than one function is registered, the power-off handler priority
+ *	selects which function will be called first.
+ *
+ *	Power-off handlers are expected to be registered from non-architecture
+ *	code, typically from drivers. A typical use case would be a system
+ *	where power-off functionality is provided through a PMIC. Multiple
+ *	power-off handlers may exist; for example, one power-off handler might
+ *	turn off the entire system, while another only turns off part of
+ *	system. In such cases, the power-off handler which only disables part
+ *	of the hardware is expected to register with low priority to ensure
+ *	that it only runs if no other means to power off the system is
+ *	available.
+ *
+ *	Currently always returns zero, as blocking_notifier_chain_register()
+ *	always returns zero.
+ */
+static int register_power_off_handler(struct notifier_block *nb)
+{
+	int ret;
+
+	ret = blocking_notifier_chain_register_unique_prio(&power_off_handler_list, nb);
+	if (ret && ret != -EBUSY)
+		return ret;
+
+	if (!ret)
+		goto set_pm_power_off;
+
+	/*
+	 * Handler must have unique priority. Otherwise call order is
+	 * determined by registration order, which is unreliable.
+	 *
+	 * This requirement will become mandatory once all drivers
+	 * will be converted to use new sys-off API.
+	 */
+	pr_err("failed to register power-off handler using unique priority\n");
+
+	ret = blocking_notifier_chain_register(&power_off_handler_list, nb);
+	if (ret)
+		return ret;
+
+	/*
+	 * Some drivers check whether pm_power_off was already installed.
+	 * Install dummy callback using new API to preserve old behaviour
+	 * for those drivers during period of transition to the new API.
+	 */
+set_pm_power_off:
+	if (!pm_power_off) {
+		pm_power_off = dummy_pm_power_off;
+		pm_power_off_nb = nb;
+	}
+
+	return 0;
+}
+
+static int unregister_power_off_handler(struct notifier_block *nb)
+{
+	if (nb == pm_power_off_nb) {
+		if (pm_power_off == dummy_pm_power_off)
+			pm_power_off = NULL;
+
+		pm_power_off_nb = NULL;
+	}
+
+	return blocking_notifier_chain_unregister(&power_off_handler_list, nb);
+}
+
+static void devm_unregister_power_off_handler(void *data)
+{
+	struct notifier_block *nb = data;
+
+	unregister_power_off_handler(nb);
+}
+
+static int devm_register_power_off_handler(struct device *dev,
+					   struct notifier_block *nb)
+{
+	int err;
+
+	err = register_power_off_handler(nb);
+	if (err)
+		return err;
+
+	return devm_add_action_or_reset(dev, devm_unregister_power_off_handler,
+					nb);
+}
+
+static int sys_off_handler_power_off(struct notifier_block *nb,
+				     unsigned long mode, void *unused)
+{
+	struct power_off_prep_data prep_data = {};
+	struct sys_off_handler_private_data *priv;
+	struct power_off_data data = {};
+	struct sys_off_handler *h;
+	int ret = NOTIFY_DONE;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, power_off_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+	prep_data.cb_data = h->cb_data;
+	data.cb_data = h->cb_data;
+
+	switch (mode) {
+	case POWEROFF_NORMAL:
+		if (h->power_off_cb)
+			h->power_off_cb(&data);
+
+		if (priv->simple_power_off_cb)
+			priv->simple_power_off_cb(priv->simple_power_off_cb_data);
+
+		if (priv->platform_power_off_cb)
+			priv->platform_power_off_cb();
+
+		if (!h->power_off_chaining_allowed)
+			ret = NOTIFY_STOP;
+
+		break;
+
+	case POWEROFF_PREPARE:
+		if (h->power_off_prepare_cb)
+			h->power_off_prepare_cb(&prep_data);
+
+		break;
+
+	default:
+		unreachable();
+	}
+
+	return ret;
+}
+
+static int sys_off_handler_restart(struct notifier_block *nb,
+				   unsigned long mode, void *cmd)
+{
+	struct sys_off_handler_private_data *priv;
+	struct restart_data data = {};
+	struct sys_off_handler *h;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, restart_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+
+	data.stop_chain = h->restart_chaining_disallowed;
+	data.cb_data = h->cb_data;
+	data.mode = mode;
+	data.cmd = cmd;
+
+	h->restart_cb(&data);
+
+	return data.stop_chain ? NOTIFY_STOP : NOTIFY_DONE;
+}
+
+static int sys_off_handler_reboot(struct notifier_block *nb,
+				  unsigned long mode, void *cmd)
+{
+	struct sys_off_handler_private_data *priv;
+	struct reboot_prep_data data = {};
+	struct sys_off_handler *h;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, reboot_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+
+	data.cb_data = h->cb_data;
+	data.stop_chain = false;
+	data.mode = mode;
+	data.cmd = cmd;
+
+	h->reboot_prepare_cb(&data);
+
+	return data.stop_chain ? NOTIFY_STOP : NOTIFY_DONE;
+}
+
+static struct sys_off_handler_private_data *
+sys_off_handler_private_data(struct sys_off_handler *handler)
+{
+	return (struct sys_off_handler_private_data *)&handler->priv;
+}
+
+/**
+ *	devm_register_sys_off_handler - Register system power-off/restart handler
+ *	@dev: Device that registers handler
+ *	@handler: System-off handler
+ *
+ *	Registers handler that will be called as last step of the power-off
+ *	and restart sequences.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int register_sys_off_handler(struct sys_off_handler *handler)
+{
+	struct sys_off_handler_private_data *priv;
+	int err, priority;
+
+	priv = sys_off_handler_private_data(handler);
+
+	/* sanity-check whether handler is registered twice */
+	if (priv->registered)
+		return -EBUSY;
+
+	if (handler->power_off_cb || handler->power_off_prepare_cb) {
+		if (handler->power_off_priority == POWEROFF_PRIO_RESERVED)
+			priority = POWEROFF_PRIO_DEFAULT;
+		else
+			priority = handler->power_off_priority;
+
+		priv->power_off_nb.notifier_call = sys_off_handler_power_off;
+		priv->power_off_nb.priority = priority;
+
+		err = register_power_off_handler(&priv->power_off_nb);
+		if (err)
+			goto reset_sys_off_handler;
+	}
+
+	if (handler->restart_cb) {
+		if (handler->restart_priority == RESTART_PRIO_RESERVED)
+			priority = RESTART_PRIO_DEFAULT;
+		else
+			priority = handler->restart_priority;
+
+		priv->restart_nb.notifier_call = sys_off_handler_restart;
+		priv->restart_nb.priority = priority;
+
+		err = register_restart_handler(&priv->restart_nb);
+		if (err)
+			goto unreg_power_off_handler;
+	}
+
+	if (handler->reboot_prepare_cb) {
+		priv->reboot_nb.notifier_call = sys_off_handler_reboot;
+		priv->reboot_nb.priority = handler->reboot_priority;
+
+		err = register_reboot_notifier(&priv->reboot_nb);
+		if (err)
+			goto unreg_restart_handler;
+	}
+
+	priv->registered = true;
+
+	return 0;
+
+unreg_restart_handler:
+	if (handler->restart_cb)
+		unregister_restart_handler(&priv->restart_nb);
+
+unreg_power_off_handler:
+	if (handler->power_off_cb)
+		unregister_power_off_handler(&priv->power_off_nb);
+
+reset_sys_off_handler:
+	memset(priv, 0, sizeof(*priv));
+
+	return err;
+}
+EXPORT_SYMBOL(register_sys_off_handler);
+
+/**
+ *	unregister_sys_off_handler - Unregister system power-off/restart handler
+ *	@handler: System-off handler
+ *
+ *	Unregisters sys-off handler. Does nothing and returns zero if handler
+ *	is NULL.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int unregister_sys_off_handler(struct sys_off_handler *handler)
+{
+	struct sys_off_handler_private_data *priv;
+	int err = 0;
+
+	if (!handler)
+		return 0;
+
+	priv = sys_off_handler_private_data(handler);
+
+	/* sanity-check whether handler is unregistered twice */
+	if (!priv->registered)
+		return -EINVAL;
+
+	if (handler->reboot_prepare_cb)
+		err |= unregister_reboot_notifier(&priv->reboot_nb);
+
+	if (handler->restart_cb)
+		err |= unregister_restart_handler(&priv->restart_nb);
+
+	if (handler->power_off_cb)
+		err |= unregister_power_off_handler(&priv->power_off_nb);
+
+	memset(priv, 0, sizeof(*priv));
+
+	return err ? -EINVAL : 0;
+}
+EXPORT_SYMBOL(unregister_sys_off_handler);
+
+static void devm_unregister_sys_off_handler(void *data)
+{
+	struct sys_off_handler *handler = data;
+
+	unregister_sys_off_handler(handler);
+}
+
+/**
+ *	devm_register_sys_off_handler - Register system power-off/restart handler
+ *	@dev: Device that registers handler
+ *	@handler: System-off handler
+ *
+ *	Resource-managed variant of register_sys_off_handler().
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_sys_off_handler(struct device *dev,
+				  struct sys_off_handler *handler)
+{
+	int err;
+
+	err = register_sys_off_handler(handler);
+	if (err)
+		return err;
+
+	return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler,
+					handler);
+}
+EXPORT_SYMBOL(devm_register_sys_off_handler);
+
+/**
+ *	devm_register_prioritized_power_off_handler - Register prioritized power-off callback
+ *	@dev: Device that registers callback
+ *	@priority: Callback's priority
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed power-off callback with a given priority.
+ *	It will be called as last step of the power-off sequence. Callbacks
+ *	chaining is disabled, i.e. further lower priority callbacks won't
+ *	be executed if this @callback will fail to execute.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_prioritized_power_off_handler(struct device *dev,
+						int priority,
+						void (*callback)(void *data),
+						void *cb_data)
+{
+	struct sys_off_handler_private_data *priv;
+	struct sys_off_handler *handler;
+
+	handler = devm_kzalloc(dev, sizeof(*handler), GFP_KERNEL);
+	if (!handler)
+		return -ENOMEM;
+
+	if (priority == POWEROFF_PRIO_RESERVED)
+		priority = POWEROFF_PRIO_DEFAULT;
+
+	priv = sys_off_handler_private_data(handler);
+
+	priv->power_off_nb.notifier_call = sys_off_handler_power_off;
+	priv->power_off_nb.priority = priority;
+	priv->simple_power_off_cb_data = cb_data;
+	priv->simple_power_off_cb = callback;
+
+	return devm_register_power_off_handler(dev, &priv->power_off_nb);
+}
+EXPORT_SYMBOL(devm_register_prioritized_power_off_handler);
+
+/**
+ *	devm_register_prioritized_restart_handler - Register prioritized restart callback
+ *	@dev: Device that registers callback
+ *	@priority: Callback's priority
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed restart callback with a given priority.
+ *	It will be called as a part of the restart sequence. Callbacks
+ *	chaining is disabled, i.e. further lower priority callbacks won't
+ *	be executed if this @callback will fail to execute.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_prioritized_restart_handler(struct device *dev,
+					      int priority,
+					      void (*callback)(struct restart_data *data),
+					      void *cb_data)
+{
+	struct sys_off_handler *handler;
+
+	handler = devm_kzalloc(dev, sizeof(*handler), GFP_KERNEL);
+	if (!handler)
+		return -ENOMEM;
+
+	if (priority == RESTART_PRIO_RESERVED)
+		priority = RESTART_PRIO_DEFAULT;
+
+	handler->restart_priority = priority;
+	handler->restart_cb = callback;
+	handler->cb_data = cb_data;
+
+	return devm_register_sys_off_handler(dev, handler);
+}
+EXPORT_SYMBOL(devm_register_prioritized_restart_handler);
+
+static struct sys_off_handler platform_power_off_handler = {
+	.priv = {
+		.power_off_nb = {
+			.notifier_call = sys_off_handler_power_off,
+			.priority = POWEROFF_PRIO_PLATFORM,
+		},
+	},
+};
+
+static DEFINE_SPINLOCK(platform_power_off_lock);
+
+/**
+ *	register_platform_power_off - Register platform-level power-off callback
+ *	@power_off: Power-off callback
+ *
+ *	Registers power-off callback that will be called as last step
+ *	of the power-off sequence. This callback is expected to be invoked
+ *	for the last resort. Further lower priority callbacks won't be
+ *	executed if @power_off fails. Only one platform power-off callback
+ *	is allowed to be registered at a time.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int register_platform_power_off(void (*power_off)(void))
+{
+	struct sys_off_handler_private_data *priv;
+	int ret = 0;
+
+	priv = sys_off_handler_private_data(&platform_power_off_handler);
+
+	spin_lock(&platform_power_off_lock);
+	if (priv->platform_power_off_cb)
+		ret = -EBUSY;
+	else
+		priv->platform_power_off_cb = power_off;
+	spin_unlock(&platform_power_off_lock);
+
+	if (ret)
+		return ret;
+
+	ret = register_power_off_handler(&priv->power_off_nb);
+	if (ret)
+		priv->platform_power_off_cb = NULL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_platform_power_off);
+
+/**
+ *	unregister_platform_power_off - Unregister platform-level power-off callback
+ *	@power_off: Power-off callback
+ *
+ *	Unregisters previously registered platform power-off callback.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int unregister_platform_power_off(void (*power_off)(void))
+{
+	struct sys_off_handler_private_data *priv;
+	int ret;
+
+	priv = sys_off_handler_private_data(&platform_power_off_handler);
+
+	if (priv->platform_power_off_cb != power_off)
+		return -EINVAL;
+
+	ret = unregister_power_off_handler(&priv->power_off_nb);
+	priv->platform_power_off_cb = NULL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_platform_power_off);
+
+/**
+ *	do_kernel_power_off - Execute kernel power-off handler call chain
+ *
+ *	Calls functions registered with register_power_off_handler.
+ *
+ *	Expected to be called as last step of the power-off sequence.
+ *
+ *	Powers off the system immediately if a power-off handler function has
+ *	been registered. Otherwise does nothing.
+ */
+void do_kernel_power_off(void)
+{
+	/* legacy pm_power_off() is unchained and has highest priority */
+	if (pm_power_off && pm_power_off != dummy_pm_power_off)
+		return pm_power_off();
+
+	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_NORMAL,
+				     NULL);
+}
+
+static void do_kernel_power_off_prepare(void)
+{
+	/* legacy pm_power_off_prepare() is unchained and has highest priority */
+	if (pm_power_off_prepare)
+		return pm_power_off_prepare();
+
+	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_PREPARE,
+				     NULL);
+}
+
 /**
  *	kernel_power_off - power_off the system
  *
@@ -304,8 +845,7 @@ EXPORT_SYMBOL_GPL(kernel_halt);
 void kernel_power_off(void)
 {
 	kernel_shutdown_prepare(SYSTEM_POWER_OFF);
-	if (pm_power_off_prepare)
-		pm_power_off_prepare();
+	do_kernel_power_off_prepare();
 	migrate_to_reboot_cpu();
 	syscore_shutdown();
 	pr_emerg("Power down\n");
@@ -314,6 +854,16 @@ void kernel_power_off(void)
 }
 EXPORT_SYMBOL_GPL(kernel_power_off);
 
+bool kernel_can_power_off(void)
+{
+	if (!pm_power_off &&
+	    blocking_notifier_call_chain_is_empty(&power_off_handler_list))
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(kernel_can_power_off);
+
 DEFINE_MUTEX(system_transition_mutex);
 
 /*
@@ -355,7 +905,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 	/* Instead of trying to make the power_off code look like
 	 * halt when pm_power_off is not set do it the easy way.
 	 */
-	if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
+	if (cmd == LINUX_REBOOT_CMD_POWER_OFF && !kernel_can_power_off())
 		cmd = LINUX_REBOOT_CMD_HALT;
 
 	mutex_lock(&system_transition_mutex);
-- 
2.33.1


_______________________________________________
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

SoC platforms often have multiple ways of how to perform system's
power-off and restart operations. Meanwhile today's kernel is limited to
a single option. Add combined power-off+restart handler call chain API,
which is inspired by the restart API. The new API provides both power-off
and restart functionality.

The old pm_power_off method will be kept around till all users are
converted to the new API.

Current restart API will be replaced by the new unified API since
new API is its superset. The restart functionality of the sys-off handler
API is built upon the existing restart-notifier APIs.

In order to ease conversion to the new API, convenient helpers are added
for the common use-cases. They will reduce amount of boilerplate code and
remove global variables. These helpers preserve old behaviour for cases
where only one power-off handler is expected, this is what all existing
drivers want, and thus, they could be easily converted to the new API.
Users of the new API should explicitly enable power-off chaining by
setting corresponding flag of the power_handler structure.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/reboot.h   | 265 ++++++++++++++++++-
 kernel/power/hibernate.c |   2 +-
 kernel/reboot.c          | 556 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 815 insertions(+), 8 deletions(-)

diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index af907a3d68d1..c2fa8d63c129 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -8,10 +8,35 @@
 
 struct device;
 
-#define SYS_DOWN	0x0001	/* Notify of system down */
-#define SYS_RESTART	SYS_DOWN
-#define SYS_HALT	0x0002	/* Notify of system halt */
-#define SYS_POWER_OFF	0x0003	/* Notify of system power off */
+enum reboot_prepare_mode {
+	SYS_DOWN = 1,		/* Notify of system down */
+	SYS_RESTART = SYS_DOWN,
+	SYS_HALT,		/* Notify of system halt */
+	SYS_POWER_OFF,		/* Notify of system power off */
+};
+
+/*
+ * Standard restart priority levels. Intended to be set in the
+ * sys_off_handler.restart_priority field.
+ *
+ * Use `RESTART_PRIO_ABC +- prio` style for additional levels.
+ *
+ * RESTART_PRIO_RESERVED:	Falls back to RESTART_PRIO_DEFAULT.
+ *				Drivers may leave priority initialized
+ *				to zero, to auto-set it to the default level.
+ *
+ * RESTART_PRIO_LOW:		Use this for handler of last resort.
+ *
+ * RESTART_PRIO_DEFAULT:	Use this for default/generic handler.
+ *
+ * RESTART_PRIO_HIGH:		Use this if you have multiple handlers and
+ *				this handler has higher priority than the
+ *				default handler.
+ */
+#define RESTART_PRIO_RESERVED		0
+#define RESTART_PRIO_LOW		8
+#define RESTART_PRIO_DEFAULT		128
+#define RESTART_PRIO_HIGH		192
 
 enum reboot_mode {
 	REBOOT_UNDEFINED = -1,
@@ -49,6 +74,237 @@ extern int register_restart_handler(struct notifier_block *);
 extern int unregister_restart_handler(struct notifier_block *);
 extern void do_kernel_restart(char *cmd);
 
+/*
+ * System power-off and restart API.
+ */
+
+/*
+ * Standard power-off priority levels. Intended to be set in the
+ * sys_off_handler.power_off_priority field.
+ *
+ * Use `POWEROFF_PRIO_ABC +- prio` style for additional levels.
+ *
+ * POWEROFF_PRIO_RESERVED:	Falls back to POWEROFF_PRIO_DEFAULT.
+ *				Drivers may leave priority initialized
+ *				to zero, to auto-set it to the default level.
+ *
+ * POWEROFF_PRIO_PLATFORM:	Intended to be used by platform-level handler.
+ *				Has lowest priority since device drivers are
+ *				expected to take over platform handler which
+ *				doesn't allow further callback chaining.
+ *
+ * POWEROFF_PRIO_DEFAULT:	Use this for default/generic handler.
+ *
+ * POWEROFF_PRIO_FIRMWARE:	Use this if handler uses firmware call.
+ *				Has highest priority since firmware is expected
+ *				to know best how to power-off hardware properly.
+ */
+#define POWEROFF_PRIO_RESERVED		0
+#define POWEROFF_PRIO_PLATFORM		1
+#define POWEROFF_PRIO_DEFAULT		128
+#define POWEROFF_PRIO_HIGH		192
+#define POWEROFF_PRIO_FIRMWARE		224
+
+enum poweroff_mode {
+	POWEROFF_NORMAL = 0,
+	POWEROFF_PREPARE,
+};
+
+/**
+ * struct power_off_data - Power-off callback argument
+ *
+ * @cb_data: Callback data.
+ */
+struct power_off_data {
+	void *cb_data;
+};
+
+/**
+ * struct power_off_prep_data - Power-off preparation callback argument
+ *
+ * @cb_data: Callback data.
+ */
+struct power_off_prep_data {
+	void *cb_data;
+};
+
+/**
+ * struct restart_data - Restart callback argument
+ *
+ * @cb_data: Callback data.
+ * @cmd: Restart command string.
+ * @stop_chain: Further lower priority callbacks won't be executed if set to
+ *		true. Can be changed within callback. Default is false.
+ * @mode: Reboot mode ID.
+ */
+struct restart_data {
+	void *cb_data;
+	const char *cmd;
+	bool stop_chain;
+	enum reboot_mode mode;
+};
+
+/**
+ * struct reboot_prep_data - Reboot and shutdown preparation callback argument
+ *
+ * @cb_data: Callback data.
+ * @cmd: Restart command string.
+ * @stop_chain: Further lower priority callbacks won't be executed if set to
+ *		true. Can be changed within callback. Default is false.
+ * @mode: Preparation mode ID.
+ */
+struct reboot_prep_data {
+	void *cb_data;
+	const char *cmd;
+	bool stop_chain;
+	enum reboot_prepare_mode mode;
+};
+
+struct sys_off_handler_private_data {
+	struct notifier_block power_off_nb;
+	struct notifier_block restart_nb;
+	struct notifier_block reboot_nb;
+	void (*platform_power_off_cb)(void);
+	void (*simple_power_off_cb)(void *data);
+	void *simple_power_off_cb_data;
+	bool registered;
+};
+
+/**
+ * struct sys_off_handler - System power-off and restart handler
+ *
+ * @cb_data: Pointer to user's data.
+ *
+ * @power_off_cb: Callback that powers off this machine. Inactive if NULL.
+ *
+ * @power_off_prepare_cb: Power-off preparation callback. All power-off
+ * preparation callbacks are invoked after @reboot_prepare_cb and before
+ * @power_off_cb. Inactive if NULL.
+ *
+ * @power_off_priority: Power-off callback priority, must be unique.
+ * Zero value is reserved and auto-reassigned to POWEROFF_PRIO_DEFAULT.
+ * Inactive if @power_off_cb is NULL.
+ *
+ * @power_off_chaining_allowed: Set to false if callback's execution should
+ * stop when @power_off_cb fails to power off this machine. True if further
+ * lower priority power-off callback should be executed. False is default
+ * value.
+ *
+ * @restart_cb: Callback that reboots this machine. Inactive if NULL.
+ *
+ * @restart_priority: Restart callback priority, must be unique. Zero value
+ * is reserved and auto-reassigned to RESTART_PRIO_DEFAULT. Inactive if
+ * @restart_cb is NULL.
+ *
+ * @restart_chaining_disallowed: Set to true if callback's execution should
+ * stop when @restart_cb fails to restart this machine. False if further
+ * lower priority restart callback should be executed. False is default
+ * value.
+ *
+ * @reboot_prepare_cb: Reboot/shutdown preparation callback. All reboot
+ * preparation callbacks are invoked before @restart_cb or @power_off_cb,
+ * depending on the mode. It's registered with register_reboot_notifier().
+ * The point is to remove boilerplate code from drivers which use this
+ * callback in conjunction with the restart/power-off callbacks.
+ *
+ * @reboot_priority: Reboot/shutdown preparation callback priority, doesn't
+ * need to be unique. Zero is default value. Inactive if @reboot_prepare_cb
+ * is NULL.
+ *
+ * @priv: Internal data. Shouldn't be touched.
+ *
+ * Describes power-off and restart handlers which are invoked by kernel
+ * to power off or restart this machine. Supports prioritized chaining for
+ * both restart and power-off handlers.
+ *
+ * Struct sys_off_handler can be static. Members of this structure must not be
+ * altered while handler is registered.
+ *
+ * Fill the structure members and pass it to @register_sys_off_handler().
+ */
+struct sys_off_handler {
+	void *cb_data;
+
+	void (*power_off_cb)(struct power_off_data *data);
+	void (*power_off_prepare_cb)(struct power_off_prep_data *data);
+	int power_off_priority;
+	bool power_off_chaining_allowed;
+
+	void (*restart_cb)(struct restart_data *data);
+	int restart_priority;
+	bool restart_chaining_disallowed;
+
+	void (*reboot_prepare_cb)(struct reboot_prep_data *data);
+	int reboot_priority;
+
+	const struct sys_off_handler_private_data priv;
+};
+
+int register_sys_off_handler(struct sys_off_handler *handler);
+int unregister_sys_off_handler(struct sys_off_handler *handler);
+
+int devm_register_sys_off_handler(struct device *dev,
+				  struct sys_off_handler *handler);
+
+int devm_register_prioritized_power_off_handler(struct device *dev,
+						int priority,
+						void (*callback)(void *data),
+						void *cb_data);
+
+/**
+ *	devm_register_simple_power_off_handler - Register simple power-off callback
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed power-off callback with default priority.
+ *	It will be invoked as last step of the power-off sequence. Further
+ *	lower priority callbacks won't be executed if this @callback fails.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+static inline int
+devm_register_simple_power_off_handler(struct device *dev,
+				       void (*callback)(void *data),
+				       void *cb_data)
+{
+	return devm_register_prioritized_power_off_handler(dev,
+							   POWEROFF_PRIO_DEFAULT,
+							   callback, cb_data);
+}
+
+int register_platform_power_off(void (*power_off)(void));
+int unregister_platform_power_off(void (*power_off)(void));
+
+int devm_register_prioritized_restart_handler(struct device *dev,
+					      int priority,
+					      void (*callback)(struct restart_data *data),
+					      void *cb_data);
+
+/**
+ *	devm_register_simple_restart_handler - Register simple restart callback
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed restart callback with default priority.
+ *	It will be invoked as a part of the restart sequence. Further
+ *	lower priority callback will be executed if this @callback fails.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+static inline int
+devm_register_simple_restart_handler(struct device *dev,
+				     void (*callback)(struct restart_data *data),
+				     void *cb_data)
+{
+	return devm_register_prioritized_restart_handler(dev,
+							 RESTART_PRIO_DEFAULT,
+							 callback, cb_data);
+}
+
+void do_kernel_power_off(void);
+
 /*
  * Architecture-specific implementations of sys_reboot commands.
  */
@@ -70,6 +326,7 @@ extern void kernel_restart_prepare(char *cmd);
 extern void kernel_restart(char *cmd);
 extern void kernel_halt(void);
 extern void kernel_power_off(void);
+extern bool kernel_can_power_off(void);
 
 extern int C_A_D; /* for sysctl */
 void ctrl_alt_del(void);
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index e6af502c2fd7..aebbdd757fb9 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -666,7 +666,7 @@ static void power_down(void)
 		hibernation_platform_enter();
 		fallthrough;
 	case HIBERNATION_SHUTDOWN:
-		if (pm_power_off)
+		if (kernel_can_power_off())
 			kernel_power_off();
 		break;
 	}
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 35f0cde641c1..3085873a876f 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -296,6 +296,547 @@ void kernel_halt(void)
 }
 EXPORT_SYMBOL_GPL(kernel_halt);
 
+/*
+ *	Notifier list for kernel code which wants to be called
+ *	to power off the system.
+ */
+static BLOCKING_NOTIFIER_HEAD(power_off_handler_list);
+
+/*
+ * Temporary stub that prevents linkage failure while we're in process
+ * of removing all uses of legacy pm_power_off() around the kernel.
+ */
+void __weak (*pm_power_off)(void);
+
+static void dummy_pm_power_off(void)
+{
+	/* temporary stub until pm_power_off() is gone, see more below */
+}
+
+static struct notifier_block *pm_power_off_nb;
+
+/**
+ *	register_power_off_handler - Register function to be called to power off
+ *				     the system
+ *	@nb: Info about handler function to be called
+ *	@nb->priority:	Handler priority. Handlers should follow the
+ *			following guidelines for setting priorities.
+ *			0:	Reserved
+ *			1:	Power-off handler of last resort,
+ *				with limited power-off capabilities
+ *			128:	Default power-off handler; use if no other
+ *				power-off handler is expected to be available,
+ *				and/or if power-off functionality is
+ *				sufficient to power-off the entire system
+ *			255:	Highest priority power-off handler, will
+ *				preempt all other power-off handlers
+ *
+ *	Registers a function with code to be called to power off the
+ *	system.
+ *
+ *	Registered functions will be called as last step of the power-off
+ *	sequence.
+ *
+ *	Registered functions are expected to power off the system immediately.
+ *	If more than one function is registered, the power-off handler priority
+ *	selects which function will be called first.
+ *
+ *	Power-off handlers are expected to be registered from non-architecture
+ *	code, typically from drivers. A typical use case would be a system
+ *	where power-off functionality is provided through a PMIC. Multiple
+ *	power-off handlers may exist; for example, one power-off handler might
+ *	turn off the entire system, while another only turns off part of
+ *	system. In such cases, the power-off handler which only disables part
+ *	of the hardware is expected to register with low priority to ensure
+ *	that it only runs if no other means to power off the system is
+ *	available.
+ *
+ *	Currently always returns zero, as blocking_notifier_chain_register()
+ *	always returns zero.
+ */
+static int register_power_off_handler(struct notifier_block *nb)
+{
+	int ret;
+
+	ret = blocking_notifier_chain_register_unique_prio(&power_off_handler_list, nb);
+	if (ret && ret != -EBUSY)
+		return ret;
+
+	if (!ret)
+		goto set_pm_power_off;
+
+	/*
+	 * Handler must have unique priority. Otherwise call order is
+	 * determined by registration order, which is unreliable.
+	 *
+	 * This requirement will become mandatory once all drivers
+	 * will be converted to use new sys-off API.
+	 */
+	pr_err("failed to register power-off handler using unique priority\n");
+
+	ret = blocking_notifier_chain_register(&power_off_handler_list, nb);
+	if (ret)
+		return ret;
+
+	/*
+	 * Some drivers check whether pm_power_off was already installed.
+	 * Install dummy callback using new API to preserve old behaviour
+	 * for those drivers during period of transition to the new API.
+	 */
+set_pm_power_off:
+	if (!pm_power_off) {
+		pm_power_off = dummy_pm_power_off;
+		pm_power_off_nb = nb;
+	}
+
+	return 0;
+}
+
+static int unregister_power_off_handler(struct notifier_block *nb)
+{
+	if (nb == pm_power_off_nb) {
+		if (pm_power_off == dummy_pm_power_off)
+			pm_power_off = NULL;
+
+		pm_power_off_nb = NULL;
+	}
+
+	return blocking_notifier_chain_unregister(&power_off_handler_list, nb);
+}
+
+static void devm_unregister_power_off_handler(void *data)
+{
+	struct notifier_block *nb = data;
+
+	unregister_power_off_handler(nb);
+}
+
+static int devm_register_power_off_handler(struct device *dev,
+					   struct notifier_block *nb)
+{
+	int err;
+
+	err = register_power_off_handler(nb);
+	if (err)
+		return err;
+
+	return devm_add_action_or_reset(dev, devm_unregister_power_off_handler,
+					nb);
+}
+
+static int sys_off_handler_power_off(struct notifier_block *nb,
+				     unsigned long mode, void *unused)
+{
+	struct power_off_prep_data prep_data = {};
+	struct sys_off_handler_private_data *priv;
+	struct power_off_data data = {};
+	struct sys_off_handler *h;
+	int ret = NOTIFY_DONE;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, power_off_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+	prep_data.cb_data = h->cb_data;
+	data.cb_data = h->cb_data;
+
+	switch (mode) {
+	case POWEROFF_NORMAL:
+		if (h->power_off_cb)
+			h->power_off_cb(&data);
+
+		if (priv->simple_power_off_cb)
+			priv->simple_power_off_cb(priv->simple_power_off_cb_data);
+
+		if (priv->platform_power_off_cb)
+			priv->platform_power_off_cb();
+
+		if (!h->power_off_chaining_allowed)
+			ret = NOTIFY_STOP;
+
+		break;
+
+	case POWEROFF_PREPARE:
+		if (h->power_off_prepare_cb)
+			h->power_off_prepare_cb(&prep_data);
+
+		break;
+
+	default:
+		unreachable();
+	}
+
+	return ret;
+}
+
+static int sys_off_handler_restart(struct notifier_block *nb,
+				   unsigned long mode, void *cmd)
+{
+	struct sys_off_handler_private_data *priv;
+	struct restart_data data = {};
+	struct sys_off_handler *h;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, restart_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+
+	data.stop_chain = h->restart_chaining_disallowed;
+	data.cb_data = h->cb_data;
+	data.mode = mode;
+	data.cmd = cmd;
+
+	h->restart_cb(&data);
+
+	return data.stop_chain ? NOTIFY_STOP : NOTIFY_DONE;
+}
+
+static int sys_off_handler_reboot(struct notifier_block *nb,
+				  unsigned long mode, void *cmd)
+{
+	struct sys_off_handler_private_data *priv;
+	struct reboot_prep_data data = {};
+	struct sys_off_handler *h;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, reboot_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+
+	data.cb_data = h->cb_data;
+	data.stop_chain = false;
+	data.mode = mode;
+	data.cmd = cmd;
+
+	h->reboot_prepare_cb(&data);
+
+	return data.stop_chain ? NOTIFY_STOP : NOTIFY_DONE;
+}
+
+static struct sys_off_handler_private_data *
+sys_off_handler_private_data(struct sys_off_handler *handler)
+{
+	return (struct sys_off_handler_private_data *)&handler->priv;
+}
+
+/**
+ *	devm_register_sys_off_handler - Register system power-off/restart handler
+ *	@dev: Device that registers handler
+ *	@handler: System-off handler
+ *
+ *	Registers handler that will be called as last step of the power-off
+ *	and restart sequences.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int register_sys_off_handler(struct sys_off_handler *handler)
+{
+	struct sys_off_handler_private_data *priv;
+	int err, priority;
+
+	priv = sys_off_handler_private_data(handler);
+
+	/* sanity-check whether handler is registered twice */
+	if (priv->registered)
+		return -EBUSY;
+
+	if (handler->power_off_cb || handler->power_off_prepare_cb) {
+		if (handler->power_off_priority == POWEROFF_PRIO_RESERVED)
+			priority = POWEROFF_PRIO_DEFAULT;
+		else
+			priority = handler->power_off_priority;
+
+		priv->power_off_nb.notifier_call = sys_off_handler_power_off;
+		priv->power_off_nb.priority = priority;
+
+		err = register_power_off_handler(&priv->power_off_nb);
+		if (err)
+			goto reset_sys_off_handler;
+	}
+
+	if (handler->restart_cb) {
+		if (handler->restart_priority == RESTART_PRIO_RESERVED)
+			priority = RESTART_PRIO_DEFAULT;
+		else
+			priority = handler->restart_priority;
+
+		priv->restart_nb.notifier_call = sys_off_handler_restart;
+		priv->restart_nb.priority = priority;
+
+		err = register_restart_handler(&priv->restart_nb);
+		if (err)
+			goto unreg_power_off_handler;
+	}
+
+	if (handler->reboot_prepare_cb) {
+		priv->reboot_nb.notifier_call = sys_off_handler_reboot;
+		priv->reboot_nb.priority = handler->reboot_priority;
+
+		err = register_reboot_notifier(&priv->reboot_nb);
+		if (err)
+			goto unreg_restart_handler;
+	}
+
+	priv->registered = true;
+
+	return 0;
+
+unreg_restart_handler:
+	if (handler->restart_cb)
+		unregister_restart_handler(&priv->restart_nb);
+
+unreg_power_off_handler:
+	if (handler->power_off_cb)
+		unregister_power_off_handler(&priv->power_off_nb);
+
+reset_sys_off_handler:
+	memset(priv, 0, sizeof(*priv));
+
+	return err;
+}
+EXPORT_SYMBOL(register_sys_off_handler);
+
+/**
+ *	unregister_sys_off_handler - Unregister system power-off/restart handler
+ *	@handler: System-off handler
+ *
+ *	Unregisters sys-off handler. Does nothing and returns zero if handler
+ *	is NULL.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int unregister_sys_off_handler(struct sys_off_handler *handler)
+{
+	struct sys_off_handler_private_data *priv;
+	int err = 0;
+
+	if (!handler)
+		return 0;
+
+	priv = sys_off_handler_private_data(handler);
+
+	/* sanity-check whether handler is unregistered twice */
+	if (!priv->registered)
+		return -EINVAL;
+
+	if (handler->reboot_prepare_cb)
+		err |= unregister_reboot_notifier(&priv->reboot_nb);
+
+	if (handler->restart_cb)
+		err |= unregister_restart_handler(&priv->restart_nb);
+
+	if (handler->power_off_cb)
+		err |= unregister_power_off_handler(&priv->power_off_nb);
+
+	memset(priv, 0, sizeof(*priv));
+
+	return err ? -EINVAL : 0;
+}
+EXPORT_SYMBOL(unregister_sys_off_handler);
+
+static void devm_unregister_sys_off_handler(void *data)
+{
+	struct sys_off_handler *handler = data;
+
+	unregister_sys_off_handler(handler);
+}
+
+/**
+ *	devm_register_sys_off_handler - Register system power-off/restart handler
+ *	@dev: Device that registers handler
+ *	@handler: System-off handler
+ *
+ *	Resource-managed variant of register_sys_off_handler().
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_sys_off_handler(struct device *dev,
+				  struct sys_off_handler *handler)
+{
+	int err;
+
+	err = register_sys_off_handler(handler);
+	if (err)
+		return err;
+
+	return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler,
+					handler);
+}
+EXPORT_SYMBOL(devm_register_sys_off_handler);
+
+/**
+ *	devm_register_prioritized_power_off_handler - Register prioritized power-off callback
+ *	@dev: Device that registers callback
+ *	@priority: Callback's priority
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed power-off callback with a given priority.
+ *	It will be called as last step of the power-off sequence. Callbacks
+ *	chaining is disabled, i.e. further lower priority callbacks won't
+ *	be executed if this @callback will fail to execute.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_prioritized_power_off_handler(struct device *dev,
+						int priority,
+						void (*callback)(void *data),
+						void *cb_data)
+{
+	struct sys_off_handler_private_data *priv;
+	struct sys_off_handler *handler;
+
+	handler = devm_kzalloc(dev, sizeof(*handler), GFP_KERNEL);
+	if (!handler)
+		return -ENOMEM;
+
+	if (priority == POWEROFF_PRIO_RESERVED)
+		priority = POWEROFF_PRIO_DEFAULT;
+
+	priv = sys_off_handler_private_data(handler);
+
+	priv->power_off_nb.notifier_call = sys_off_handler_power_off;
+	priv->power_off_nb.priority = priority;
+	priv->simple_power_off_cb_data = cb_data;
+	priv->simple_power_off_cb = callback;
+
+	return devm_register_power_off_handler(dev, &priv->power_off_nb);
+}
+EXPORT_SYMBOL(devm_register_prioritized_power_off_handler);
+
+/**
+ *	devm_register_prioritized_restart_handler - Register prioritized restart callback
+ *	@dev: Device that registers callback
+ *	@priority: Callback's priority
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed restart callback with a given priority.
+ *	It will be called as a part of the restart sequence. Callbacks
+ *	chaining is disabled, i.e. further lower priority callbacks won't
+ *	be executed if this @callback will fail to execute.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_prioritized_restart_handler(struct device *dev,
+					      int priority,
+					      void (*callback)(struct restart_data *data),
+					      void *cb_data)
+{
+	struct sys_off_handler *handler;
+
+	handler = devm_kzalloc(dev, sizeof(*handler), GFP_KERNEL);
+	if (!handler)
+		return -ENOMEM;
+
+	if (priority == RESTART_PRIO_RESERVED)
+		priority = RESTART_PRIO_DEFAULT;
+
+	handler->restart_priority = priority;
+	handler->restart_cb = callback;
+	handler->cb_data = cb_data;
+
+	return devm_register_sys_off_handler(dev, handler);
+}
+EXPORT_SYMBOL(devm_register_prioritized_restart_handler);
+
+static struct sys_off_handler platform_power_off_handler = {
+	.priv = {
+		.power_off_nb = {
+			.notifier_call = sys_off_handler_power_off,
+			.priority = POWEROFF_PRIO_PLATFORM,
+		},
+	},
+};
+
+static DEFINE_SPINLOCK(platform_power_off_lock);
+
+/**
+ *	register_platform_power_off - Register platform-level power-off callback
+ *	@power_off: Power-off callback
+ *
+ *	Registers power-off callback that will be called as last step
+ *	of the power-off sequence. This callback is expected to be invoked
+ *	for the last resort. Further lower priority callbacks won't be
+ *	executed if @power_off fails. Only one platform power-off callback
+ *	is allowed to be registered at a time.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int register_platform_power_off(void (*power_off)(void))
+{
+	struct sys_off_handler_private_data *priv;
+	int ret = 0;
+
+	priv = sys_off_handler_private_data(&platform_power_off_handler);
+
+	spin_lock(&platform_power_off_lock);
+	if (priv->platform_power_off_cb)
+		ret = -EBUSY;
+	else
+		priv->platform_power_off_cb = power_off;
+	spin_unlock(&platform_power_off_lock);
+
+	if (ret)
+		return ret;
+
+	ret = register_power_off_handler(&priv->power_off_nb);
+	if (ret)
+		priv->platform_power_off_cb = NULL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_platform_power_off);
+
+/**
+ *	unregister_platform_power_off - Unregister platform-level power-off callback
+ *	@power_off: Power-off callback
+ *
+ *	Unregisters previously registered platform power-off callback.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int unregister_platform_power_off(void (*power_off)(void))
+{
+	struct sys_off_handler_private_data *priv;
+	int ret;
+
+	priv = sys_off_handler_private_data(&platform_power_off_handler);
+
+	if (priv->platform_power_off_cb != power_off)
+		return -EINVAL;
+
+	ret = unregister_power_off_handler(&priv->power_off_nb);
+	priv->platform_power_off_cb = NULL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_platform_power_off);
+
+/**
+ *	do_kernel_power_off - Execute kernel power-off handler call chain
+ *
+ *	Calls functions registered with register_power_off_handler.
+ *
+ *	Expected to be called as last step of the power-off sequence.
+ *
+ *	Powers off the system immediately if a power-off handler function has
+ *	been registered. Otherwise does nothing.
+ */
+void do_kernel_power_off(void)
+{
+	/* legacy pm_power_off() is unchained and has highest priority */
+	if (pm_power_off && pm_power_off != dummy_pm_power_off)
+		return pm_power_off();
+
+	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_NORMAL,
+				     NULL);
+}
+
+static void do_kernel_power_off_prepare(void)
+{
+	/* legacy pm_power_off_prepare() is unchained and has highest priority */
+	if (pm_power_off_prepare)
+		return pm_power_off_prepare();
+
+	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_PREPARE,
+				     NULL);
+}
+
 /**
  *	kernel_power_off - power_off the system
  *
@@ -304,8 +845,7 @@ EXPORT_SYMBOL_GPL(kernel_halt);
 void kernel_power_off(void)
 {
 	kernel_shutdown_prepare(SYSTEM_POWER_OFF);
-	if (pm_power_off_prepare)
-		pm_power_off_prepare();
+	do_kernel_power_off_prepare();
 	migrate_to_reboot_cpu();
 	syscore_shutdown();
 	pr_emerg("Power down\n");
@@ -314,6 +854,16 @@ void kernel_power_off(void)
 }
 EXPORT_SYMBOL_GPL(kernel_power_off);
 
+bool kernel_can_power_off(void)
+{
+	if (!pm_power_off &&
+	    blocking_notifier_call_chain_is_empty(&power_off_handler_list))
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(kernel_can_power_off);
+
 DEFINE_MUTEX(system_transition_mutex);
 
 /*
@@ -355,7 +905,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 	/* Instead of trying to make the power_off code look like
 	 * halt when pm_power_off is not set do it the easy way.
 	 */
-	if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
+	if (cmd == LINUX_REBOOT_CMD_POWER_OFF && !kernel_can_power_off())
 		cmd = LINUX_REBOOT_CMD_HALT;
 
 	mutex_lock(&system_transition_mutex);
-- 
2.33.1

[PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

SoC platforms often have multiple ways of how to perform system's
power-off and restart operations. Meanwhile today's kernel is limited to
a single option. Add combined power-off+restart handler call chain API,
which is inspired by the restart API. The new API provides both power-off
and restart functionality.

The old pm_power_off method will be kept around till all users are
converted to the new API.

Current restart API will be replaced by the new unified API since
new API is its superset. The restart functionality of the sys-off handler
API is built upon the existing restart-notifier APIs.

In order to ease conversion to the new API, convenient helpers are added
for the common use-cases. They will reduce amount of boilerplate code and
remove global variables. These helpers preserve old behaviour for cases
where only one power-off handler is expected, this is what all existing
drivers want, and thus, they could be easily converted to the new API.
Users of the new API should explicitly enable power-off chaining by
setting corresponding flag of the power_handler structure.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/reboot.h   | 265 ++++++++++++++++++-
 kernel/power/hibernate.c |   2 +-
 kernel/reboot.c          | 556 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 815 insertions(+), 8 deletions(-)

diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index af907a3d68d1..c2fa8d63c129 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -8,10 +8,35 @@
 
 struct device;
 
-#define SYS_DOWN	0x0001	/* Notify of system down */
-#define SYS_RESTART	SYS_DOWN
-#define SYS_HALT	0x0002	/* Notify of system halt */
-#define SYS_POWER_OFF	0x0003	/* Notify of system power off */
+enum reboot_prepare_mode {
+	SYS_DOWN = 1,		/* Notify of system down */
+	SYS_RESTART = SYS_DOWN,
+	SYS_HALT,		/* Notify of system halt */
+	SYS_POWER_OFF,		/* Notify of system power off */
+};
+
+/*
+ * Standard restart priority levels. Intended to be set in the
+ * sys_off_handler.restart_priority field.
+ *
+ * Use `RESTART_PRIO_ABC +- prio` style for additional levels.
+ *
+ * RESTART_PRIO_RESERVED:	Falls back to RESTART_PRIO_DEFAULT.
+ *				Drivers may leave priority initialized
+ *				to zero, to auto-set it to the default level.
+ *
+ * RESTART_PRIO_LOW:		Use this for handler of last resort.
+ *
+ * RESTART_PRIO_DEFAULT:	Use this for default/generic handler.
+ *
+ * RESTART_PRIO_HIGH:		Use this if you have multiple handlers and
+ *				this handler has higher priority than the
+ *				default handler.
+ */
+#define RESTART_PRIO_RESERVED		0
+#define RESTART_PRIO_LOW		8
+#define RESTART_PRIO_DEFAULT		128
+#define RESTART_PRIO_HIGH		192
 
 enum reboot_mode {
 	REBOOT_UNDEFINED = -1,
@@ -49,6 +74,237 @@ extern int register_restart_handler(struct notifier_block *);
 extern int unregister_restart_handler(struct notifier_block *);
 extern void do_kernel_restart(char *cmd);
 
+/*
+ * System power-off and restart API.
+ */
+
+/*
+ * Standard power-off priority levels. Intended to be set in the
+ * sys_off_handler.power_off_priority field.
+ *
+ * Use `POWEROFF_PRIO_ABC +- prio` style for additional levels.
+ *
+ * POWEROFF_PRIO_RESERVED:	Falls back to POWEROFF_PRIO_DEFAULT.
+ *				Drivers may leave priority initialized
+ *				to zero, to auto-set it to the default level.
+ *
+ * POWEROFF_PRIO_PLATFORM:	Intended to be used by platform-level handler.
+ *				Has lowest priority since device drivers are
+ *				expected to take over platform handler which
+ *				doesn't allow further callback chaining.
+ *
+ * POWEROFF_PRIO_DEFAULT:	Use this for default/generic handler.
+ *
+ * POWEROFF_PRIO_FIRMWARE:	Use this if handler uses firmware call.
+ *				Has highest priority since firmware is expected
+ *				to know best how to power-off hardware properly.
+ */
+#define POWEROFF_PRIO_RESERVED		0
+#define POWEROFF_PRIO_PLATFORM		1
+#define POWEROFF_PRIO_DEFAULT		128
+#define POWEROFF_PRIO_HIGH		192
+#define POWEROFF_PRIO_FIRMWARE		224
+
+enum poweroff_mode {
+	POWEROFF_NORMAL = 0,
+	POWEROFF_PREPARE,
+};
+
+/**
+ * struct power_off_data - Power-off callback argument
+ *
+ * @cb_data: Callback data.
+ */
+struct power_off_data {
+	void *cb_data;
+};
+
+/**
+ * struct power_off_prep_data - Power-off preparation callback argument
+ *
+ * @cb_data: Callback data.
+ */
+struct power_off_prep_data {
+	void *cb_data;
+};
+
+/**
+ * struct restart_data - Restart callback argument
+ *
+ * @cb_data: Callback data.
+ * @cmd: Restart command string.
+ * @stop_chain: Further lower priority callbacks won't be executed if set to
+ *		true. Can be changed within callback. Default is false.
+ * @mode: Reboot mode ID.
+ */
+struct restart_data {
+	void *cb_data;
+	const char *cmd;
+	bool stop_chain;
+	enum reboot_mode mode;
+};
+
+/**
+ * struct reboot_prep_data - Reboot and shutdown preparation callback argument
+ *
+ * @cb_data: Callback data.
+ * @cmd: Restart command string.
+ * @stop_chain: Further lower priority callbacks won't be executed if set to
+ *		true. Can be changed within callback. Default is false.
+ * @mode: Preparation mode ID.
+ */
+struct reboot_prep_data {
+	void *cb_data;
+	const char *cmd;
+	bool stop_chain;
+	enum reboot_prepare_mode mode;
+};
+
+struct sys_off_handler_private_data {
+	struct notifier_block power_off_nb;
+	struct notifier_block restart_nb;
+	struct notifier_block reboot_nb;
+	void (*platform_power_off_cb)(void);
+	void (*simple_power_off_cb)(void *data);
+	void *simple_power_off_cb_data;
+	bool registered;
+};
+
+/**
+ * struct sys_off_handler - System power-off and restart handler
+ *
+ * @cb_data: Pointer to user's data.
+ *
+ * @power_off_cb: Callback that powers off this machine. Inactive if NULL.
+ *
+ * @power_off_prepare_cb: Power-off preparation callback. All power-off
+ * preparation callbacks are invoked after @reboot_prepare_cb and before
+ * @power_off_cb. Inactive if NULL.
+ *
+ * @power_off_priority: Power-off callback priority, must be unique.
+ * Zero value is reserved and auto-reassigned to POWEROFF_PRIO_DEFAULT.
+ * Inactive if @power_off_cb is NULL.
+ *
+ * @power_off_chaining_allowed: Set to false if callback's execution should
+ * stop when @power_off_cb fails to power off this machine. True if further
+ * lower priority power-off callback should be executed. False is default
+ * value.
+ *
+ * @restart_cb: Callback that reboots this machine. Inactive if NULL.
+ *
+ * @restart_priority: Restart callback priority, must be unique. Zero value
+ * is reserved and auto-reassigned to RESTART_PRIO_DEFAULT. Inactive if
+ * @restart_cb is NULL.
+ *
+ * @restart_chaining_disallowed: Set to true if callback's execution should
+ * stop when @restart_cb fails to restart this machine. False if further
+ * lower priority restart callback should be executed. False is default
+ * value.
+ *
+ * @reboot_prepare_cb: Reboot/shutdown preparation callback. All reboot
+ * preparation callbacks are invoked before @restart_cb or @power_off_cb,
+ * depending on the mode. It's registered with register_reboot_notifier().
+ * The point is to remove boilerplate code from drivers which use this
+ * callback in conjunction with the restart/power-off callbacks.
+ *
+ * @reboot_priority: Reboot/shutdown preparation callback priority, doesn't
+ * need to be unique. Zero is default value. Inactive if @reboot_prepare_cb
+ * is NULL.
+ *
+ * @priv: Internal data. Shouldn't be touched.
+ *
+ * Describes power-off and restart handlers which are invoked by kernel
+ * to power off or restart this machine. Supports prioritized chaining for
+ * both restart and power-off handlers.
+ *
+ * Struct sys_off_handler can be static. Members of this structure must not be
+ * altered while handler is registered.
+ *
+ * Fill the structure members and pass it to @register_sys_off_handler().
+ */
+struct sys_off_handler {
+	void *cb_data;
+
+	void (*power_off_cb)(struct power_off_data *data);
+	void (*power_off_prepare_cb)(struct power_off_prep_data *data);
+	int power_off_priority;
+	bool power_off_chaining_allowed;
+
+	void (*restart_cb)(struct restart_data *data);
+	int restart_priority;
+	bool restart_chaining_disallowed;
+
+	void (*reboot_prepare_cb)(struct reboot_prep_data *data);
+	int reboot_priority;
+
+	const struct sys_off_handler_private_data priv;
+};
+
+int register_sys_off_handler(struct sys_off_handler *handler);
+int unregister_sys_off_handler(struct sys_off_handler *handler);
+
+int devm_register_sys_off_handler(struct device *dev,
+				  struct sys_off_handler *handler);
+
+int devm_register_prioritized_power_off_handler(struct device *dev,
+						int priority,
+						void (*callback)(void *data),
+						void *cb_data);
+
+/**
+ *	devm_register_simple_power_off_handler - Register simple power-off callback
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed power-off callback with default priority.
+ *	It will be invoked as last step of the power-off sequence. Further
+ *	lower priority callbacks won't be executed if this @callback fails.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+static inline int
+devm_register_simple_power_off_handler(struct device *dev,
+				       void (*callback)(void *data),
+				       void *cb_data)
+{
+	return devm_register_prioritized_power_off_handler(dev,
+							   POWEROFF_PRIO_DEFAULT,
+							   callback, cb_data);
+}
+
+int register_platform_power_off(void (*power_off)(void));
+int unregister_platform_power_off(void (*power_off)(void));
+
+int devm_register_prioritized_restart_handler(struct device *dev,
+					      int priority,
+					      void (*callback)(struct restart_data *data),
+					      void *cb_data);
+
+/**
+ *	devm_register_simple_restart_handler - Register simple restart callback
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed restart callback with default priority.
+ *	It will be invoked as a part of the restart sequence. Further
+ *	lower priority callback will be executed if this @callback fails.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+static inline int
+devm_register_simple_restart_handler(struct device *dev,
+				     void (*callback)(struct restart_data *data),
+				     void *cb_data)
+{
+	return devm_register_prioritized_restart_handler(dev,
+							 RESTART_PRIO_DEFAULT,
+							 callback, cb_data);
+}
+
+void do_kernel_power_off(void);
+
 /*
  * Architecture-specific implementations of sys_reboot commands.
  */
@@ -70,6 +326,7 @@ extern void kernel_restart_prepare(char *cmd);
 extern void kernel_restart(char *cmd);
 extern void kernel_halt(void);
 extern void kernel_power_off(void);
+extern bool kernel_can_power_off(void);
 
 extern int C_A_D; /* for sysctl */
 void ctrl_alt_del(void);
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index e6af502c2fd7..aebbdd757fb9 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -666,7 +666,7 @@ static void power_down(void)
 		hibernation_platform_enter();
 		fallthrough;
 	case HIBERNATION_SHUTDOWN:
-		if (pm_power_off)
+		if (kernel_can_power_off())
 			kernel_power_off();
 		break;
 	}
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 35f0cde641c1..3085873a876f 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -296,6 +296,547 @@ void kernel_halt(void)
 }
 EXPORT_SYMBOL_GPL(kernel_halt);
 
+/*
+ *	Notifier list for kernel code which wants to be called
+ *	to power off the system.
+ */
+static BLOCKING_NOTIFIER_HEAD(power_off_handler_list);
+
+/*
+ * Temporary stub that prevents linkage failure while we're in process
+ * of removing all uses of legacy pm_power_off() around the kernel.
+ */
+void __weak (*pm_power_off)(void);
+
+static void dummy_pm_power_off(void)
+{
+	/* temporary stub until pm_power_off() is gone, see more below */
+}
+
+static struct notifier_block *pm_power_off_nb;
+
+/**
+ *	register_power_off_handler - Register function to be called to power off
+ *				     the system
+ *	@nb: Info about handler function to be called
+ *	@nb->priority:	Handler priority. Handlers should follow the
+ *			following guidelines for setting priorities.
+ *			0:	Reserved
+ *			1:	Power-off handler of last resort,
+ *				with limited power-off capabilities
+ *			128:	Default power-off handler; use if no other
+ *				power-off handler is expected to be available,
+ *				and/or if power-off functionality is
+ *				sufficient to power-off the entire system
+ *			255:	Highest priority power-off handler, will
+ *				preempt all other power-off handlers
+ *
+ *	Registers a function with code to be called to power off the
+ *	system.
+ *
+ *	Registered functions will be called as last step of the power-off
+ *	sequence.
+ *
+ *	Registered functions are expected to power off the system immediately.
+ *	If more than one function is registered, the power-off handler priority
+ *	selects which function will be called first.
+ *
+ *	Power-off handlers are expected to be registered from non-architecture
+ *	code, typically from drivers. A typical use case would be a system
+ *	where power-off functionality is provided through a PMIC. Multiple
+ *	power-off handlers may exist; for example, one power-off handler might
+ *	turn off the entire system, while another only turns off part of
+ *	system. In such cases, the power-off handler which only disables part
+ *	of the hardware is expected to register with low priority to ensure
+ *	that it only runs if no other means to power off the system is
+ *	available.
+ *
+ *	Currently always returns zero, as blocking_notifier_chain_register()
+ *	always returns zero.
+ */
+static int register_power_off_handler(struct notifier_block *nb)
+{
+	int ret;
+
+	ret = blocking_notifier_chain_register_unique_prio(&power_off_handler_list, nb);
+	if (ret && ret != -EBUSY)
+		return ret;
+
+	if (!ret)
+		goto set_pm_power_off;
+
+	/*
+	 * Handler must have unique priority. Otherwise call order is
+	 * determined by registration order, which is unreliable.
+	 *
+	 * This requirement will become mandatory once all drivers
+	 * will be converted to use new sys-off API.
+	 */
+	pr_err("failed to register power-off handler using unique priority\n");
+
+	ret = blocking_notifier_chain_register(&power_off_handler_list, nb);
+	if (ret)
+		return ret;
+
+	/*
+	 * Some drivers check whether pm_power_off was already installed.
+	 * Install dummy callback using new API to preserve old behaviour
+	 * for those drivers during period of transition to the new API.
+	 */
+set_pm_power_off:
+	if (!pm_power_off) {
+		pm_power_off = dummy_pm_power_off;
+		pm_power_off_nb = nb;
+	}
+
+	return 0;
+}
+
+static int unregister_power_off_handler(struct notifier_block *nb)
+{
+	if (nb == pm_power_off_nb) {
+		if (pm_power_off == dummy_pm_power_off)
+			pm_power_off = NULL;
+
+		pm_power_off_nb = NULL;
+	}
+
+	return blocking_notifier_chain_unregister(&power_off_handler_list, nb);
+}
+
+static void devm_unregister_power_off_handler(void *data)
+{
+	struct notifier_block *nb = data;
+
+	unregister_power_off_handler(nb);
+}
+
+static int devm_register_power_off_handler(struct device *dev,
+					   struct notifier_block *nb)
+{
+	int err;
+
+	err = register_power_off_handler(nb);
+	if (err)
+		return err;
+
+	return devm_add_action_or_reset(dev, devm_unregister_power_off_handler,
+					nb);
+}
+
+static int sys_off_handler_power_off(struct notifier_block *nb,
+				     unsigned long mode, void *unused)
+{
+	struct power_off_prep_data prep_data = {};
+	struct sys_off_handler_private_data *priv;
+	struct power_off_data data = {};
+	struct sys_off_handler *h;
+	int ret = NOTIFY_DONE;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, power_off_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+	prep_data.cb_data = h->cb_data;
+	data.cb_data = h->cb_data;
+
+	switch (mode) {
+	case POWEROFF_NORMAL:
+		if (h->power_off_cb)
+			h->power_off_cb(&data);
+
+		if (priv->simple_power_off_cb)
+			priv->simple_power_off_cb(priv->simple_power_off_cb_data);
+
+		if (priv->platform_power_off_cb)
+			priv->platform_power_off_cb();
+
+		if (!h->power_off_chaining_allowed)
+			ret = NOTIFY_STOP;
+
+		break;
+
+	case POWEROFF_PREPARE:
+		if (h->power_off_prepare_cb)
+			h->power_off_prepare_cb(&prep_data);
+
+		break;
+
+	default:
+		unreachable();
+	}
+
+	return ret;
+}
+
+static int sys_off_handler_restart(struct notifier_block *nb,
+				   unsigned long mode, void *cmd)
+{
+	struct sys_off_handler_private_data *priv;
+	struct restart_data data = {};
+	struct sys_off_handler *h;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, restart_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+
+	data.stop_chain = h->restart_chaining_disallowed;
+	data.cb_data = h->cb_data;
+	data.mode = mode;
+	data.cmd = cmd;
+
+	h->restart_cb(&data);
+
+	return data.stop_chain ? NOTIFY_STOP : NOTIFY_DONE;
+}
+
+static int sys_off_handler_reboot(struct notifier_block *nb,
+				  unsigned long mode, void *cmd)
+{
+	struct sys_off_handler_private_data *priv;
+	struct reboot_prep_data data = {};
+	struct sys_off_handler *h;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, reboot_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+
+	data.cb_data = h->cb_data;
+	data.stop_chain = false;
+	data.mode = mode;
+	data.cmd = cmd;
+
+	h->reboot_prepare_cb(&data);
+
+	return data.stop_chain ? NOTIFY_STOP : NOTIFY_DONE;
+}
+
+static struct sys_off_handler_private_data *
+sys_off_handler_private_data(struct sys_off_handler *handler)
+{
+	return (struct sys_off_handler_private_data *)&handler->priv;
+}
+
+/**
+ *	devm_register_sys_off_handler - Register system power-off/restart handler
+ *	@dev: Device that registers handler
+ *	@handler: System-off handler
+ *
+ *	Registers handler that will be called as last step of the power-off
+ *	and restart sequences.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int register_sys_off_handler(struct sys_off_handler *handler)
+{
+	struct sys_off_handler_private_data *priv;
+	int err, priority;
+
+	priv = sys_off_handler_private_data(handler);
+
+	/* sanity-check whether handler is registered twice */
+	if (priv->registered)
+		return -EBUSY;
+
+	if (handler->power_off_cb || handler->power_off_prepare_cb) {
+		if (handler->power_off_priority == POWEROFF_PRIO_RESERVED)
+			priority = POWEROFF_PRIO_DEFAULT;
+		else
+			priority = handler->power_off_priority;
+
+		priv->power_off_nb.notifier_call = sys_off_handler_power_off;
+		priv->power_off_nb.priority = priority;
+
+		err = register_power_off_handler(&priv->power_off_nb);
+		if (err)
+			goto reset_sys_off_handler;
+	}
+
+	if (handler->restart_cb) {
+		if (handler->restart_priority == RESTART_PRIO_RESERVED)
+			priority = RESTART_PRIO_DEFAULT;
+		else
+			priority = handler->restart_priority;
+
+		priv->restart_nb.notifier_call = sys_off_handler_restart;
+		priv->restart_nb.priority = priority;
+
+		err = register_restart_handler(&priv->restart_nb);
+		if (err)
+			goto unreg_power_off_handler;
+	}
+
+	if (handler->reboot_prepare_cb) {
+		priv->reboot_nb.notifier_call = sys_off_handler_reboot;
+		priv->reboot_nb.priority = handler->reboot_priority;
+
+		err = register_reboot_notifier(&priv->reboot_nb);
+		if (err)
+			goto unreg_restart_handler;
+	}
+
+	priv->registered = true;
+
+	return 0;
+
+unreg_restart_handler:
+	if (handler->restart_cb)
+		unregister_restart_handler(&priv->restart_nb);
+
+unreg_power_off_handler:
+	if (handler->power_off_cb)
+		unregister_power_off_handler(&priv->power_off_nb);
+
+reset_sys_off_handler:
+	memset(priv, 0, sizeof(*priv));
+
+	return err;
+}
+EXPORT_SYMBOL(register_sys_off_handler);
+
+/**
+ *	unregister_sys_off_handler - Unregister system power-off/restart handler
+ *	@handler: System-off handler
+ *
+ *	Unregisters sys-off handler. Does nothing and returns zero if handler
+ *	is NULL.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int unregister_sys_off_handler(struct sys_off_handler *handler)
+{
+	struct sys_off_handler_private_data *priv;
+	int err = 0;
+
+	if (!handler)
+		return 0;
+
+	priv = sys_off_handler_private_data(handler);
+
+	/* sanity-check whether handler is unregistered twice */
+	if (!priv->registered)
+		return -EINVAL;
+
+	if (handler->reboot_prepare_cb)
+		err |= unregister_reboot_notifier(&priv->reboot_nb);
+
+	if (handler->restart_cb)
+		err |= unregister_restart_handler(&priv->restart_nb);
+
+	if (handler->power_off_cb)
+		err |= unregister_power_off_handler(&priv->power_off_nb);
+
+	memset(priv, 0, sizeof(*priv));
+
+	return err ? -EINVAL : 0;
+}
+EXPORT_SYMBOL(unregister_sys_off_handler);
+
+static void devm_unregister_sys_off_handler(void *data)
+{
+	struct sys_off_handler *handler = data;
+
+	unregister_sys_off_handler(handler);
+}
+
+/**
+ *	devm_register_sys_off_handler - Register system power-off/restart handler
+ *	@dev: Device that registers handler
+ *	@handler: System-off handler
+ *
+ *	Resource-managed variant of register_sys_off_handler().
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_sys_off_handler(struct device *dev,
+				  struct sys_off_handler *handler)
+{
+	int err;
+
+	err = register_sys_off_handler(handler);
+	if (err)
+		return err;
+
+	return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler,
+					handler);
+}
+EXPORT_SYMBOL(devm_register_sys_off_handler);
+
+/**
+ *	devm_register_prioritized_power_off_handler - Register prioritized power-off callback
+ *	@dev: Device that registers callback
+ *	@priority: Callback's priority
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed power-off callback with a given priority.
+ *	It will be called as last step of the power-off sequence. Callbacks
+ *	chaining is disabled, i.e. further lower priority callbacks won't
+ *	be executed if this @callback will fail to execute.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_prioritized_power_off_handler(struct device *dev,
+						int priority,
+						void (*callback)(void *data),
+						void *cb_data)
+{
+	struct sys_off_handler_private_data *priv;
+	struct sys_off_handler *handler;
+
+	handler = devm_kzalloc(dev, sizeof(*handler), GFP_KERNEL);
+	if (!handler)
+		return -ENOMEM;
+
+	if (priority == POWEROFF_PRIO_RESERVED)
+		priority = POWEROFF_PRIO_DEFAULT;
+
+	priv = sys_off_handler_private_data(handler);
+
+	priv->power_off_nb.notifier_call = sys_off_handler_power_off;
+	priv->power_off_nb.priority = priority;
+	priv->simple_power_off_cb_data = cb_data;
+	priv->simple_power_off_cb = callback;
+
+	return devm_register_power_off_handler(dev, &priv->power_off_nb);
+}
+EXPORT_SYMBOL(devm_register_prioritized_power_off_handler);
+
+/**
+ *	devm_register_prioritized_restart_handler - Register prioritized restart callback
+ *	@dev: Device that registers callback
+ *	@priority: Callback's priority
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed restart callback with a given priority.
+ *	It will be called as a part of the restart sequence. Callbacks
+ *	chaining is disabled, i.e. further lower priority callbacks won't
+ *	be executed if this @callback will fail to execute.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_prioritized_restart_handler(struct device *dev,
+					      int priority,
+					      void (*callback)(struct restart_data *data),
+					      void *cb_data)
+{
+	struct sys_off_handler *handler;
+
+	handler = devm_kzalloc(dev, sizeof(*handler), GFP_KERNEL);
+	if (!handler)
+		return -ENOMEM;
+
+	if (priority == RESTART_PRIO_RESERVED)
+		priority = RESTART_PRIO_DEFAULT;
+
+	handler->restart_priority = priority;
+	handler->restart_cb = callback;
+	handler->cb_data = cb_data;
+
+	return devm_register_sys_off_handler(dev, handler);
+}
+EXPORT_SYMBOL(devm_register_prioritized_restart_handler);
+
+static struct sys_off_handler platform_power_off_handler = {
+	.priv = {
+		.power_off_nb = {
+			.notifier_call = sys_off_handler_power_off,
+			.priority = POWEROFF_PRIO_PLATFORM,
+		},
+	},
+};
+
+static DEFINE_SPINLOCK(platform_power_off_lock);
+
+/**
+ *	register_platform_power_off - Register platform-level power-off callback
+ *	@power_off: Power-off callback
+ *
+ *	Registers power-off callback that will be called as last step
+ *	of the power-off sequence. This callback is expected to be invoked
+ *	for the last resort. Further lower priority callbacks won't be
+ *	executed if @power_off fails. Only one platform power-off callback
+ *	is allowed to be registered at a time.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int register_platform_power_off(void (*power_off)(void))
+{
+	struct sys_off_handler_private_data *priv;
+	int ret = 0;
+
+	priv = sys_off_handler_private_data(&platform_power_off_handler);
+
+	spin_lock(&platform_power_off_lock);
+	if (priv->platform_power_off_cb)
+		ret = -EBUSY;
+	else
+		priv->platform_power_off_cb = power_off;
+	spin_unlock(&platform_power_off_lock);
+
+	if (ret)
+		return ret;
+
+	ret = register_power_off_handler(&priv->power_off_nb);
+	if (ret)
+		priv->platform_power_off_cb = NULL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_platform_power_off);
+
+/**
+ *	unregister_platform_power_off - Unregister platform-level power-off callback
+ *	@power_off: Power-off callback
+ *
+ *	Unregisters previously registered platform power-off callback.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int unregister_platform_power_off(void (*power_off)(void))
+{
+	struct sys_off_handler_private_data *priv;
+	int ret;
+
+	priv = sys_off_handler_private_data(&platform_power_off_handler);
+
+	if (priv->platform_power_off_cb != power_off)
+		return -EINVAL;
+
+	ret = unregister_power_off_handler(&priv->power_off_nb);
+	priv->platform_power_off_cb = NULL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_platform_power_off);
+
+/**
+ *	do_kernel_power_off - Execute kernel power-off handler call chain
+ *
+ *	Calls functions registered with register_power_off_handler.
+ *
+ *	Expected to be called as last step of the power-off sequence.
+ *
+ *	Powers off the system immediately if a power-off handler function has
+ *	been registered. Otherwise does nothing.
+ */
+void do_kernel_power_off(void)
+{
+	/* legacy pm_power_off() is unchained and has highest priority */
+	if (pm_power_off && pm_power_off != dummy_pm_power_off)
+		return pm_power_off();
+
+	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_NORMAL,
+				     NULL);
+}
+
+static void do_kernel_power_off_prepare(void)
+{
+	/* legacy pm_power_off_prepare() is unchained and has highest priority */
+	if (pm_power_off_prepare)
+		return pm_power_off_prepare();
+
+	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_PREPARE,
+				     NULL);
+}
+
 /**
  *	kernel_power_off - power_off the system
  *
@@ -304,8 +845,7 @@ EXPORT_SYMBOL_GPL(kernel_halt);
 void kernel_power_off(void)
 {
 	kernel_shutdown_prepare(SYSTEM_POWER_OFF);
-	if (pm_power_off_prepare)
-		pm_power_off_prepare();
+	do_kernel_power_off_prepare();
 	migrate_to_reboot_cpu();
 	syscore_shutdown();
 	pr_emerg("Power down\n");
@@ -314,6 +854,16 @@ void kernel_power_off(void)
 }
 EXPORT_SYMBOL_GPL(kernel_power_off);
 
+bool kernel_can_power_off(void)
+{
+	if (!pm_power_off &&
+	    blocking_notifier_call_chain_is_empty(&power_off_handler_list))
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(kernel_can_power_off);
+
 DEFINE_MUTEX(system_transition_mutex);
 
 /*
@@ -355,7 +905,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 	/* Instead of trying to make the power_off code look like
 	 * halt when pm_power_off is not set do it the easy way.
 	 */
-	if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
+	if (cmd == LINUX_REBOOT_CMD_POWER_OFF && !kernel_can_power_off())
 		cmd = LINUX_REBOOT_CMD_HALT;
 
 	mutex_lock(&system_transition_mutex);
-- 
2.33.1

[PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

SoC platforms often have multiple ways of how to perform system's
power-off and restart operations. Meanwhile today's kernel is limited to
a single option. Add combined power-off+restart handler call chain API,
which is inspired by the restart API. The new API provides both power-off
and restart functionality.

The old pm_power_off method will be kept around till all users are
converted to the new API.

Current restart API will be replaced by the new unified API since
new API is its superset. The restart functionality of the sys-off handler
API is built upon the existing restart-notifier APIs.

In order to ease conversion to the new API, convenient helpers are added
for the common use-cases. They will reduce amount of boilerplate code and
remove global variables. These helpers preserve old behaviour for cases
where only one power-off handler is expected, this is what all existing
drivers want, and thus, they could be easily converted to the new API.
Users of the new API should explicitly enable power-off chaining by
setting corresponding flag of the power_handler structure.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/reboot.h   | 265 ++++++++++++++++++-
 kernel/power/hibernate.c |   2 +-
 kernel/reboot.c          | 556 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 815 insertions(+), 8 deletions(-)

diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index af907a3d68d1..c2fa8d63c129 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -8,10 +8,35 @@
 
 struct device;
 
-#define SYS_DOWN	0x0001	/* Notify of system down */
-#define SYS_RESTART	SYS_DOWN
-#define SYS_HALT	0x0002	/* Notify of system halt */
-#define SYS_POWER_OFF	0x0003	/* Notify of system power off */
+enum reboot_prepare_mode {
+	SYS_DOWN = 1,		/* Notify of system down */
+	SYS_RESTART = SYS_DOWN,
+	SYS_HALT,		/* Notify of system halt */
+	SYS_POWER_OFF,		/* Notify of system power off */
+};
+
+/*
+ * Standard restart priority levels. Intended to be set in the
+ * sys_off_handler.restart_priority field.
+ *
+ * Use `RESTART_PRIO_ABC +- prio` style for additional levels.
+ *
+ * RESTART_PRIO_RESERVED:	Falls back to RESTART_PRIO_DEFAULT.
+ *				Drivers may leave priority initialized
+ *				to zero, to auto-set it to the default level.
+ *
+ * RESTART_PRIO_LOW:		Use this for handler of last resort.
+ *
+ * RESTART_PRIO_DEFAULT:	Use this for default/generic handler.
+ *
+ * RESTART_PRIO_HIGH:		Use this if you have multiple handlers and
+ *				this handler has higher priority than the
+ *				default handler.
+ */
+#define RESTART_PRIO_RESERVED		0
+#define RESTART_PRIO_LOW		8
+#define RESTART_PRIO_DEFAULT		128
+#define RESTART_PRIO_HIGH		192
 
 enum reboot_mode {
 	REBOOT_UNDEFINED = -1,
@@ -49,6 +74,237 @@ extern int register_restart_handler(struct notifier_block *);
 extern int unregister_restart_handler(struct notifier_block *);
 extern void do_kernel_restart(char *cmd);
 
+/*
+ * System power-off and restart API.
+ */
+
+/*
+ * Standard power-off priority levels. Intended to be set in the
+ * sys_off_handler.power_off_priority field.
+ *
+ * Use `POWEROFF_PRIO_ABC +- prio` style for additional levels.
+ *
+ * POWEROFF_PRIO_RESERVED:	Falls back to POWEROFF_PRIO_DEFAULT.
+ *				Drivers may leave priority initialized
+ *				to zero, to auto-set it to the default level.
+ *
+ * POWEROFF_PRIO_PLATFORM:	Intended to be used by platform-level handler.
+ *				Has lowest priority since device drivers are
+ *				expected to take over platform handler which
+ *				doesn't allow further callback chaining.
+ *
+ * POWEROFF_PRIO_DEFAULT:	Use this for default/generic handler.
+ *
+ * POWEROFF_PRIO_FIRMWARE:	Use this if handler uses firmware call.
+ *				Has highest priority since firmware is expected
+ *				to know best how to power-off hardware properly.
+ */
+#define POWEROFF_PRIO_RESERVED		0
+#define POWEROFF_PRIO_PLATFORM		1
+#define POWEROFF_PRIO_DEFAULT		128
+#define POWEROFF_PRIO_HIGH		192
+#define POWEROFF_PRIO_FIRMWARE		224
+
+enum poweroff_mode {
+	POWEROFF_NORMAL = 0,
+	POWEROFF_PREPARE,
+};
+
+/**
+ * struct power_off_data - Power-off callback argument
+ *
+ * @cb_data: Callback data.
+ */
+struct power_off_data {
+	void *cb_data;
+};
+
+/**
+ * struct power_off_prep_data - Power-off preparation callback argument
+ *
+ * @cb_data: Callback data.
+ */
+struct power_off_prep_data {
+	void *cb_data;
+};
+
+/**
+ * struct restart_data - Restart callback argument
+ *
+ * @cb_data: Callback data.
+ * @cmd: Restart command string.
+ * @stop_chain: Further lower priority callbacks won't be executed if set to
+ *		true. Can be changed within callback. Default is false.
+ * @mode: Reboot mode ID.
+ */
+struct restart_data {
+	void *cb_data;
+	const char *cmd;
+	bool stop_chain;
+	enum reboot_mode mode;
+};
+
+/**
+ * struct reboot_prep_data - Reboot and shutdown preparation callback argument
+ *
+ * @cb_data: Callback data.
+ * @cmd: Restart command string.
+ * @stop_chain: Further lower priority callbacks won't be executed if set to
+ *		true. Can be changed within callback. Default is false.
+ * @mode: Preparation mode ID.
+ */
+struct reboot_prep_data {
+	void *cb_data;
+	const char *cmd;
+	bool stop_chain;
+	enum reboot_prepare_mode mode;
+};
+
+struct sys_off_handler_private_data {
+	struct notifier_block power_off_nb;
+	struct notifier_block restart_nb;
+	struct notifier_block reboot_nb;
+	void (*platform_power_off_cb)(void);
+	void (*simple_power_off_cb)(void *data);
+	void *simple_power_off_cb_data;
+	bool registered;
+};
+
+/**
+ * struct sys_off_handler - System power-off and restart handler
+ *
+ * @cb_data: Pointer to user's data.
+ *
+ * @power_off_cb: Callback that powers off this machine. Inactive if NULL.
+ *
+ * @power_off_prepare_cb: Power-off preparation callback. All power-off
+ * preparation callbacks are invoked after @reboot_prepare_cb and before
+ * @power_off_cb. Inactive if NULL.
+ *
+ * @power_off_priority: Power-off callback priority, must be unique.
+ * Zero value is reserved and auto-reassigned to POWEROFF_PRIO_DEFAULT.
+ * Inactive if @power_off_cb is NULL.
+ *
+ * @power_off_chaining_allowed: Set to false if callback's execution should
+ * stop when @power_off_cb fails to power off this machine. True if further
+ * lower priority power-off callback should be executed. False is default
+ * value.
+ *
+ * @restart_cb: Callback that reboots this machine. Inactive if NULL.
+ *
+ * @restart_priority: Restart callback priority, must be unique. Zero value
+ * is reserved and auto-reassigned to RESTART_PRIO_DEFAULT. Inactive if
+ * @restart_cb is NULL.
+ *
+ * @restart_chaining_disallowed: Set to true if callback's execution should
+ * stop when @restart_cb fails to restart this machine. False if further
+ * lower priority restart callback should be executed. False is default
+ * value.
+ *
+ * @reboot_prepare_cb: Reboot/shutdown preparation callback. All reboot
+ * preparation callbacks are invoked before @restart_cb or @power_off_cb,
+ * depending on the mode. It's registered with register_reboot_notifier().
+ * The point is to remove boilerplate code from drivers which use this
+ * callback in conjunction with the restart/power-off callbacks.
+ *
+ * @reboot_priority: Reboot/shutdown preparation callback priority, doesn't
+ * need to be unique. Zero is default value. Inactive if @reboot_prepare_cb
+ * is NULL.
+ *
+ * @priv: Internal data. Shouldn't be touched.
+ *
+ * Describes power-off and restart handlers which are invoked by kernel
+ * to power off or restart this machine. Supports prioritized chaining for
+ * both restart and power-off handlers.
+ *
+ * Struct sys_off_handler can be static. Members of this structure must not be
+ * altered while handler is registered.
+ *
+ * Fill the structure members and pass it to @register_sys_off_handler().
+ */
+struct sys_off_handler {
+	void *cb_data;
+
+	void (*power_off_cb)(struct power_off_data *data);
+	void (*power_off_prepare_cb)(struct power_off_prep_data *data);
+	int power_off_priority;
+	bool power_off_chaining_allowed;
+
+	void (*restart_cb)(struct restart_data *data);
+	int restart_priority;
+	bool restart_chaining_disallowed;
+
+	void (*reboot_prepare_cb)(struct reboot_prep_data *data);
+	int reboot_priority;
+
+	const struct sys_off_handler_private_data priv;
+};
+
+int register_sys_off_handler(struct sys_off_handler *handler);
+int unregister_sys_off_handler(struct sys_off_handler *handler);
+
+int devm_register_sys_off_handler(struct device *dev,
+				  struct sys_off_handler *handler);
+
+int devm_register_prioritized_power_off_handler(struct device *dev,
+						int priority,
+						void (*callback)(void *data),
+						void *cb_data);
+
+/**
+ *	devm_register_simple_power_off_handler - Register simple power-off callback
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed power-off callback with default priority.
+ *	It will be invoked as last step of the power-off sequence. Further
+ *	lower priority callbacks won't be executed if this @callback fails.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+static inline int
+devm_register_simple_power_off_handler(struct device *dev,
+				       void (*callback)(void *data),
+				       void *cb_data)
+{
+	return devm_register_prioritized_power_off_handler(dev,
+							   POWEROFF_PRIO_DEFAULT,
+							   callback, cb_data);
+}
+
+int register_platform_power_off(void (*power_off)(void));
+int unregister_platform_power_off(void (*power_off)(void));
+
+int devm_register_prioritized_restart_handler(struct device *dev,
+					      int priority,
+					      void (*callback)(struct restart_data *data),
+					      void *cb_data);
+
+/**
+ *	devm_register_simple_restart_handler - Register simple restart callback
+ *	@dev: Device that registers callback
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed restart callback with default priority.
+ *	It will be invoked as a part of the restart sequence. Further
+ *	lower priority callback will be executed if this @callback fails.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+static inline int
+devm_register_simple_restart_handler(struct device *dev,
+				     void (*callback)(struct restart_data *data),
+				     void *cb_data)
+{
+	return devm_register_prioritized_restart_handler(dev,
+							 RESTART_PRIO_DEFAULT,
+							 callback, cb_data);
+}
+
+void do_kernel_power_off(void);
+
 /*
  * Architecture-specific implementations of sys_reboot commands.
  */
@@ -70,6 +326,7 @@ extern void kernel_restart_prepare(char *cmd);
 extern void kernel_restart(char *cmd);
 extern void kernel_halt(void);
 extern void kernel_power_off(void);
+extern bool kernel_can_power_off(void);
 
 extern int C_A_D; /* for sysctl */
 void ctrl_alt_del(void);
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index e6af502c2fd7..aebbdd757fb9 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -666,7 +666,7 @@ static void power_down(void)
 		hibernation_platform_enter();
 		fallthrough;
 	case HIBERNATION_SHUTDOWN:
-		if (pm_power_off)
+		if (kernel_can_power_off())
 			kernel_power_off();
 		break;
 	}
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 35f0cde641c1..3085873a876f 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -296,6 +296,547 @@ void kernel_halt(void)
 }
 EXPORT_SYMBOL_GPL(kernel_halt);
 
+/*
+ *	Notifier list for kernel code which wants to be called
+ *	to power off the system.
+ */
+static BLOCKING_NOTIFIER_HEAD(power_off_handler_list);
+
+/*
+ * Temporary stub that prevents linkage failure while we're in process
+ * of removing all uses of legacy pm_power_off() around the kernel.
+ */
+void __weak (*pm_power_off)(void);
+
+static void dummy_pm_power_off(void)
+{
+	/* temporary stub until pm_power_off() is gone, see more below */
+}
+
+static struct notifier_block *pm_power_off_nb;
+
+/**
+ *	register_power_off_handler - Register function to be called to power off
+ *				     the system
+ *	@nb: Info about handler function to be called
+ *	@nb->priority:	Handler priority. Handlers should follow the
+ *			following guidelines for setting priorities.
+ *			0:	Reserved
+ *			1:	Power-off handler of last resort,
+ *				with limited power-off capabilities
+ *			128:	Default power-off handler; use if no other
+ *				power-off handler is expected to be available,
+ *				and/or if power-off functionality is
+ *				sufficient to power-off the entire system
+ *			255:	Highest priority power-off handler, will
+ *				preempt all other power-off handlers
+ *
+ *	Registers a function with code to be called to power off the
+ *	system.
+ *
+ *	Registered functions will be called as last step of the power-off
+ *	sequence.
+ *
+ *	Registered functions are expected to power off the system immediately.
+ *	If more than one function is registered, the power-off handler priority
+ *	selects which function will be called first.
+ *
+ *	Power-off handlers are expected to be registered from non-architecture
+ *	code, typically from drivers. A typical use case would be a system
+ *	where power-off functionality is provided through a PMIC. Multiple
+ *	power-off handlers may exist; for example, one power-off handler might
+ *	turn off the entire system, while another only turns off part of
+ *	system. In such cases, the power-off handler which only disables part
+ *	of the hardware is expected to register with low priority to ensure
+ *	that it only runs if no other means to power off the system is
+ *	available.
+ *
+ *	Currently always returns zero, as blocking_notifier_chain_register()
+ *	always returns zero.
+ */
+static int register_power_off_handler(struct notifier_block *nb)
+{
+	int ret;
+
+	ret = blocking_notifier_chain_register_unique_prio(&power_off_handler_list, nb);
+	if (ret && ret != -EBUSY)
+		return ret;
+
+	if (!ret)
+		goto set_pm_power_off;
+
+	/*
+	 * Handler must have unique priority. Otherwise call order is
+	 * determined by registration order, which is unreliable.
+	 *
+	 * This requirement will become mandatory once all drivers
+	 * will be converted to use new sys-off API.
+	 */
+	pr_err("failed to register power-off handler using unique priority\n");
+
+	ret = blocking_notifier_chain_register(&power_off_handler_list, nb);
+	if (ret)
+		return ret;
+
+	/*
+	 * Some drivers check whether pm_power_off was already installed.
+	 * Install dummy callback using new API to preserve old behaviour
+	 * for those drivers during period of transition to the new API.
+	 */
+set_pm_power_off:
+	if (!pm_power_off) {
+		pm_power_off = dummy_pm_power_off;
+		pm_power_off_nb = nb;
+	}
+
+	return 0;
+}
+
+static int unregister_power_off_handler(struct notifier_block *nb)
+{
+	if (nb = pm_power_off_nb) {
+		if (pm_power_off = dummy_pm_power_off)
+			pm_power_off = NULL;
+
+		pm_power_off_nb = NULL;
+	}
+
+	return blocking_notifier_chain_unregister(&power_off_handler_list, nb);
+}
+
+static void devm_unregister_power_off_handler(void *data)
+{
+	struct notifier_block *nb = data;
+
+	unregister_power_off_handler(nb);
+}
+
+static int devm_register_power_off_handler(struct device *dev,
+					   struct notifier_block *nb)
+{
+	int err;
+
+	err = register_power_off_handler(nb);
+	if (err)
+		return err;
+
+	return devm_add_action_or_reset(dev, devm_unregister_power_off_handler,
+					nb);
+}
+
+static int sys_off_handler_power_off(struct notifier_block *nb,
+				     unsigned long mode, void *unused)
+{
+	struct power_off_prep_data prep_data = {};
+	struct sys_off_handler_private_data *priv;
+	struct power_off_data data = {};
+	struct sys_off_handler *h;
+	int ret = NOTIFY_DONE;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, power_off_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+	prep_data.cb_data = h->cb_data;
+	data.cb_data = h->cb_data;
+
+	switch (mode) {
+	case POWEROFF_NORMAL:
+		if (h->power_off_cb)
+			h->power_off_cb(&data);
+
+		if (priv->simple_power_off_cb)
+			priv->simple_power_off_cb(priv->simple_power_off_cb_data);
+
+		if (priv->platform_power_off_cb)
+			priv->platform_power_off_cb();
+
+		if (!h->power_off_chaining_allowed)
+			ret = NOTIFY_STOP;
+
+		break;
+
+	case POWEROFF_PREPARE:
+		if (h->power_off_prepare_cb)
+			h->power_off_prepare_cb(&prep_data);
+
+		break;
+
+	default:
+		unreachable();
+	}
+
+	return ret;
+}
+
+static int sys_off_handler_restart(struct notifier_block *nb,
+				   unsigned long mode, void *cmd)
+{
+	struct sys_off_handler_private_data *priv;
+	struct restart_data data = {};
+	struct sys_off_handler *h;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, restart_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+
+	data.stop_chain = h->restart_chaining_disallowed;
+	data.cb_data = h->cb_data;
+	data.mode = mode;
+	data.cmd = cmd;
+
+	h->restart_cb(&data);
+
+	return data.stop_chain ? NOTIFY_STOP : NOTIFY_DONE;
+}
+
+static int sys_off_handler_reboot(struct notifier_block *nb,
+				  unsigned long mode, void *cmd)
+{
+	struct sys_off_handler_private_data *priv;
+	struct reboot_prep_data data = {};
+	struct sys_off_handler *h;
+
+	priv = container_of(nb, struct sys_off_handler_private_data, reboot_nb);
+	h = container_of(priv, struct sys_off_handler, priv);
+
+	data.cb_data = h->cb_data;
+	data.stop_chain = false;
+	data.mode = mode;
+	data.cmd = cmd;
+
+	h->reboot_prepare_cb(&data);
+
+	return data.stop_chain ? NOTIFY_STOP : NOTIFY_DONE;
+}
+
+static struct sys_off_handler_private_data *
+sys_off_handler_private_data(struct sys_off_handler *handler)
+{
+	return (struct sys_off_handler_private_data *)&handler->priv;
+}
+
+/**
+ *	devm_register_sys_off_handler - Register system power-off/restart handler
+ *	@dev: Device that registers handler
+ *	@handler: System-off handler
+ *
+ *	Registers handler that will be called as last step of the power-off
+ *	and restart sequences.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int register_sys_off_handler(struct sys_off_handler *handler)
+{
+	struct sys_off_handler_private_data *priv;
+	int err, priority;
+
+	priv = sys_off_handler_private_data(handler);
+
+	/* sanity-check whether handler is registered twice */
+	if (priv->registered)
+		return -EBUSY;
+
+	if (handler->power_off_cb || handler->power_off_prepare_cb) {
+		if (handler->power_off_priority = POWEROFF_PRIO_RESERVED)
+			priority = POWEROFF_PRIO_DEFAULT;
+		else
+			priority = handler->power_off_priority;
+
+		priv->power_off_nb.notifier_call = sys_off_handler_power_off;
+		priv->power_off_nb.priority = priority;
+
+		err = register_power_off_handler(&priv->power_off_nb);
+		if (err)
+			goto reset_sys_off_handler;
+	}
+
+	if (handler->restart_cb) {
+		if (handler->restart_priority = RESTART_PRIO_RESERVED)
+			priority = RESTART_PRIO_DEFAULT;
+		else
+			priority = handler->restart_priority;
+
+		priv->restart_nb.notifier_call = sys_off_handler_restart;
+		priv->restart_nb.priority = priority;
+
+		err = register_restart_handler(&priv->restart_nb);
+		if (err)
+			goto unreg_power_off_handler;
+	}
+
+	if (handler->reboot_prepare_cb) {
+		priv->reboot_nb.notifier_call = sys_off_handler_reboot;
+		priv->reboot_nb.priority = handler->reboot_priority;
+
+		err = register_reboot_notifier(&priv->reboot_nb);
+		if (err)
+			goto unreg_restart_handler;
+	}
+
+	priv->registered = true;
+
+	return 0;
+
+unreg_restart_handler:
+	if (handler->restart_cb)
+		unregister_restart_handler(&priv->restart_nb);
+
+unreg_power_off_handler:
+	if (handler->power_off_cb)
+		unregister_power_off_handler(&priv->power_off_nb);
+
+reset_sys_off_handler:
+	memset(priv, 0, sizeof(*priv));
+
+	return err;
+}
+EXPORT_SYMBOL(register_sys_off_handler);
+
+/**
+ *	unregister_sys_off_handler - Unregister system power-off/restart handler
+ *	@handler: System-off handler
+ *
+ *	Unregisters sys-off handler. Does nothing and returns zero if handler
+ *	is NULL.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int unregister_sys_off_handler(struct sys_off_handler *handler)
+{
+	struct sys_off_handler_private_data *priv;
+	int err = 0;
+
+	if (!handler)
+		return 0;
+
+	priv = sys_off_handler_private_data(handler);
+
+	/* sanity-check whether handler is unregistered twice */
+	if (!priv->registered)
+		return -EINVAL;
+
+	if (handler->reboot_prepare_cb)
+		err |= unregister_reboot_notifier(&priv->reboot_nb);
+
+	if (handler->restart_cb)
+		err |= unregister_restart_handler(&priv->restart_nb);
+
+	if (handler->power_off_cb)
+		err |= unregister_power_off_handler(&priv->power_off_nb);
+
+	memset(priv, 0, sizeof(*priv));
+
+	return err ? -EINVAL : 0;
+}
+EXPORT_SYMBOL(unregister_sys_off_handler);
+
+static void devm_unregister_sys_off_handler(void *data)
+{
+	struct sys_off_handler *handler = data;
+
+	unregister_sys_off_handler(handler);
+}
+
+/**
+ *	devm_register_sys_off_handler - Register system power-off/restart handler
+ *	@dev: Device that registers handler
+ *	@handler: System-off handler
+ *
+ *	Resource-managed variant of register_sys_off_handler().
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_sys_off_handler(struct device *dev,
+				  struct sys_off_handler *handler)
+{
+	int err;
+
+	err = register_sys_off_handler(handler);
+	if (err)
+		return err;
+
+	return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler,
+					handler);
+}
+EXPORT_SYMBOL(devm_register_sys_off_handler);
+
+/**
+ *	devm_register_prioritized_power_off_handler - Register prioritized power-off callback
+ *	@dev: Device that registers callback
+ *	@priority: Callback's priority
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed power-off callback with a given priority.
+ *	It will be called as last step of the power-off sequence. Callbacks
+ *	chaining is disabled, i.e. further lower priority callbacks won't
+ *	be executed if this @callback will fail to execute.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_prioritized_power_off_handler(struct device *dev,
+						int priority,
+						void (*callback)(void *data),
+						void *cb_data)
+{
+	struct sys_off_handler_private_data *priv;
+	struct sys_off_handler *handler;
+
+	handler = devm_kzalloc(dev, sizeof(*handler), GFP_KERNEL);
+	if (!handler)
+		return -ENOMEM;
+
+	if (priority = POWEROFF_PRIO_RESERVED)
+		priority = POWEROFF_PRIO_DEFAULT;
+
+	priv = sys_off_handler_private_data(handler);
+
+	priv->power_off_nb.notifier_call = sys_off_handler_power_off;
+	priv->power_off_nb.priority = priority;
+	priv->simple_power_off_cb_data = cb_data;
+	priv->simple_power_off_cb = callback;
+
+	return devm_register_power_off_handler(dev, &priv->power_off_nb);
+}
+EXPORT_SYMBOL(devm_register_prioritized_power_off_handler);
+
+/**
+ *	devm_register_prioritized_restart_handler - Register prioritized restart callback
+ *	@dev: Device that registers callback
+ *	@priority: Callback's priority
+ *	@callback: Callback function
+ *	@cb_data: Callback's argument
+ *
+ *	Registers resource-managed restart callback with a given priority.
+ *	It will be called as a part of the restart sequence. Callbacks
+ *	chaining is disabled, i.e. further lower priority callbacks won't
+ *	be executed if this @callback will fail to execute.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int devm_register_prioritized_restart_handler(struct device *dev,
+					      int priority,
+					      void (*callback)(struct restart_data *data),
+					      void *cb_data)
+{
+	struct sys_off_handler *handler;
+
+	handler = devm_kzalloc(dev, sizeof(*handler), GFP_KERNEL);
+	if (!handler)
+		return -ENOMEM;
+
+	if (priority = RESTART_PRIO_RESERVED)
+		priority = RESTART_PRIO_DEFAULT;
+
+	handler->restart_priority = priority;
+	handler->restart_cb = callback;
+	handler->cb_data = cb_data;
+
+	return devm_register_sys_off_handler(dev, handler);
+}
+EXPORT_SYMBOL(devm_register_prioritized_restart_handler);
+
+static struct sys_off_handler platform_power_off_handler = {
+	.priv = {
+		.power_off_nb = {
+			.notifier_call = sys_off_handler_power_off,
+			.priority = POWEROFF_PRIO_PLATFORM,
+		},
+	},
+};
+
+static DEFINE_SPINLOCK(platform_power_off_lock);
+
+/**
+ *	register_platform_power_off - Register platform-level power-off callback
+ *	@power_off: Power-off callback
+ *
+ *	Registers power-off callback that will be called as last step
+ *	of the power-off sequence. This callback is expected to be invoked
+ *	for the last resort. Further lower priority callbacks won't be
+ *	executed if @power_off fails. Only one platform power-off callback
+ *	is allowed to be registered at a time.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int register_platform_power_off(void (*power_off)(void))
+{
+	struct sys_off_handler_private_data *priv;
+	int ret = 0;
+
+	priv = sys_off_handler_private_data(&platform_power_off_handler);
+
+	spin_lock(&platform_power_off_lock);
+	if (priv->platform_power_off_cb)
+		ret = -EBUSY;
+	else
+		priv->platform_power_off_cb = power_off;
+	spin_unlock(&platform_power_off_lock);
+
+	if (ret)
+		return ret;
+
+	ret = register_power_off_handler(&priv->power_off_nb);
+	if (ret)
+		priv->platform_power_off_cb = NULL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_platform_power_off);
+
+/**
+ *	unregister_platform_power_off - Unregister platform-level power-off callback
+ *	@power_off: Power-off callback
+ *
+ *	Unregisters previously registered platform power-off callback.
+ *
+ *	Returns zero on success, or error code on failure.
+ */
+int unregister_platform_power_off(void (*power_off)(void))
+{
+	struct sys_off_handler_private_data *priv;
+	int ret;
+
+	priv = sys_off_handler_private_data(&platform_power_off_handler);
+
+	if (priv->platform_power_off_cb != power_off)
+		return -EINVAL;
+
+	ret = unregister_power_off_handler(&priv->power_off_nb);
+	priv->platform_power_off_cb = NULL;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_platform_power_off);
+
+/**
+ *	do_kernel_power_off - Execute kernel power-off handler call chain
+ *
+ *	Calls functions registered with register_power_off_handler.
+ *
+ *	Expected to be called as last step of the power-off sequence.
+ *
+ *	Powers off the system immediately if a power-off handler function has
+ *	been registered. Otherwise does nothing.
+ */
+void do_kernel_power_off(void)
+{
+	/* legacy pm_power_off() is unchained and has highest priority */
+	if (pm_power_off && pm_power_off != dummy_pm_power_off)
+		return pm_power_off();
+
+	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_NORMAL,
+				     NULL);
+}
+
+static void do_kernel_power_off_prepare(void)
+{
+	/* legacy pm_power_off_prepare() is unchained and has highest priority */
+	if (pm_power_off_prepare)
+		return pm_power_off_prepare();
+
+	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_PREPARE,
+				     NULL);
+}
+
 /**
  *	kernel_power_off - power_off the system
  *
@@ -304,8 +845,7 @@ EXPORT_SYMBOL_GPL(kernel_halt);
 void kernel_power_off(void)
 {
 	kernel_shutdown_prepare(SYSTEM_POWER_OFF);
-	if (pm_power_off_prepare)
-		pm_power_off_prepare();
+	do_kernel_power_off_prepare();
 	migrate_to_reboot_cpu();
 	syscore_shutdown();
 	pr_emerg("Power down\n");
@@ -314,6 +854,16 @@ void kernel_power_off(void)
 }
 EXPORT_SYMBOL_GPL(kernel_power_off);
 
+bool kernel_can_power_off(void)
+{
+	if (!pm_power_off &&
+	    blocking_notifier_call_chain_is_empty(&power_off_handler_list))
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(kernel_can_power_off);
+
 DEFINE_MUTEX(system_transition_mutex);
 
 /*
@@ -355,7 +905,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
 	/* Instead of trying to make the power_off code look like
 	 * halt when pm_power_off is not set do it the easy way.
 	 */
-	if ((cmd = LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
+	if (cmd = LINUX_REBOOT_CMD_POWER_OFF && !kernel_can_power_off())
 		cmd = LINUX_REBOOT_CMD_HALT;
 
 	mutex_lock(&system_transition_mutex);
-- 
2.33.1

[PATCH v5 05/21] ARM: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/arm/kernel/reboot.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 3044fcb8d073..2cb943422554 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -116,9 +116,7 @@ void machine_power_off(void)
 {
 	local_irq_disable();
 	smp_send_stop();
-
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 /*
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 05/21] ARM: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/arm/kernel/reboot.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 3044fcb8d073..2cb943422554 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -116,9 +116,7 @@ void machine_power_off(void)
 {
 	local_irq_disable();
 	smp_send_stop();
-
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 /*
-- 
2.33.1

[PATCH v5 05/21] ARM: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/arm/kernel/reboot.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 3044fcb8d073..2cb943422554 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -116,9 +116,7 @@ void machine_power_off(void)
 {
 	local_irq_disable();
 	smp_send_stop();
-
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 /*
-- 
2.33.1

[PATCH v5 05/21] ARM: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/arm/kernel/reboot.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
index 3044fcb8d073..2cb943422554 100644
--- a/arch/arm/kernel/reboot.c
+++ b/arch/arm/kernel/reboot.c
@@ -116,9 +116,7 @@ void machine_power_off(void)
 {
 	local_irq_disable();
 	smp_send_stop();
-
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 /*
-- 
2.33.1

[PATCH v5 06/21] csky: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/csky/kernel/power.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/csky/kernel/power.c b/arch/csky/kernel/power.c
index 923ee4e381b8..86ee202906f8 100644
--- a/arch/csky/kernel/power.c
+++ b/arch/csky/kernel/power.c
@@ -9,16 +9,14 @@ EXPORT_SYMBOL(pm_power_off);
 void machine_power_off(void)
 {
 	local_irq_disable();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	asm volatile ("bkpt");
 }
 
 void machine_halt(void)
 {
 	local_irq_disable();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	asm volatile ("bkpt");
 }
 
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 06/21] csky: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/csky/kernel/power.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/csky/kernel/power.c b/arch/csky/kernel/power.c
index 923ee4e381b8..86ee202906f8 100644
--- a/arch/csky/kernel/power.c
+++ b/arch/csky/kernel/power.c
@@ -9,16 +9,14 @@ EXPORT_SYMBOL(pm_power_off);
 void machine_power_off(void)
 {
 	local_irq_disable();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	asm volatile ("bkpt");
 }
 
 void machine_halt(void)
 {
 	local_irq_disable();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	asm volatile ("bkpt");
 }
 
-- 
2.33.1

[PATCH v5 06/21] csky: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/csky/kernel/power.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/csky/kernel/power.c b/arch/csky/kernel/power.c
index 923ee4e381b8..86ee202906f8 100644
--- a/arch/csky/kernel/power.c
+++ b/arch/csky/kernel/power.c
@@ -9,16 +9,14 @@ EXPORT_SYMBOL(pm_power_off);
 void machine_power_off(void)
 {
 	local_irq_disable();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	asm volatile ("bkpt");
 }
 
 void machine_halt(void)
 {
 	local_irq_disable();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	asm volatile ("bkpt");
 }
 
-- 
2.33.1

[PATCH v5 06/21] csky: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/csky/kernel/power.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/csky/kernel/power.c b/arch/csky/kernel/power.c
index 923ee4e381b8..86ee202906f8 100644
--- a/arch/csky/kernel/power.c
+++ b/arch/csky/kernel/power.c
@@ -9,16 +9,14 @@ EXPORT_SYMBOL(pm_power_off);
 void machine_power_off(void)
 {
 	local_irq_disable();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	asm volatile ("bkpt");
 }
 
 void machine_halt(void)
 {
 	local_irq_disable();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	asm volatile ("bkpt");
 }
 
-- 
2.33.1

[PATCH v5 07/21] riscv: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/riscv/kernel/reset.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
index 9c842c41684a..912288572226 100644
--- a/arch/riscv/kernel/reset.c
+++ b/arch/riscv/kernel/reset.c
@@ -23,16 +23,12 @@ void machine_restart(char *cmd)
 
 void machine_halt(void)
 {
-	if (pm_power_off != NULL)
-		pm_power_off();
-	else
-		default_power_off();
+	do_kernel_power_off();
+	default_power_off();
 }
 
 void machine_power_off(void)
 {
-	if (pm_power_off != NULL)
-		pm_power_off();
-	else
-		default_power_off();
+	do_kernel_power_off();
+	default_power_off();
 }
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 07/21] riscv: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/riscv/kernel/reset.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
index 9c842c41684a..912288572226 100644
--- a/arch/riscv/kernel/reset.c
+++ b/arch/riscv/kernel/reset.c
@@ -23,16 +23,12 @@ void machine_restart(char *cmd)
 
 void machine_halt(void)
 {
-	if (pm_power_off != NULL)
-		pm_power_off();
-	else
-		default_power_off();
+	do_kernel_power_off();
+	default_power_off();
 }
 
 void machine_power_off(void)
 {
-	if (pm_power_off != NULL)
-		pm_power_off();
-	else
-		default_power_off();
+	do_kernel_power_off();
+	default_power_off();
 }
-- 
2.33.1

[PATCH v5 07/21] riscv: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/riscv/kernel/reset.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
index 9c842c41684a..912288572226 100644
--- a/arch/riscv/kernel/reset.c
+++ b/arch/riscv/kernel/reset.c
@@ -23,16 +23,12 @@ void machine_restart(char *cmd)
 
 void machine_halt(void)
 {
-	if (pm_power_off != NULL)
-		pm_power_off();
-	else
-		default_power_off();
+	do_kernel_power_off();
+	default_power_off();
 }
 
 void machine_power_off(void)
 {
-	if (pm_power_off != NULL)
-		pm_power_off();
-	else
-		default_power_off();
+	do_kernel_power_off();
+	default_power_off();
 }
-- 
2.33.1

[PATCH v5 07/21] riscv: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/riscv/kernel/reset.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
index 9c842c41684a..912288572226 100644
--- a/arch/riscv/kernel/reset.c
+++ b/arch/riscv/kernel/reset.c
@@ -23,16 +23,12 @@ void machine_restart(char *cmd)
 
 void machine_halt(void)
 {
-	if (pm_power_off != NULL)
-		pm_power_off();
-	else
-		default_power_off();
+	do_kernel_power_off();
+	default_power_off();
 }
 
 void machine_power_off(void)
 {
-	if (pm_power_off != NULL)
-		pm_power_off();
-	else
-		default_power_off();
+	do_kernel_power_off();
+	default_power_off();
 }
-- 
2.33.1

[PATCH v5 08/21] arm64: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/arm64/kernel/process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index aacf2f5559a8..f8db031afa7d 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -110,8 +110,7 @@ void machine_power_off(void)
 {
 	local_irq_disable();
 	smp_send_stop();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 /*
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 08/21] arm64: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/arm64/kernel/process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index aacf2f5559a8..f8db031afa7d 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -110,8 +110,7 @@ void machine_power_off(void)
 {
 	local_irq_disable();
 	smp_send_stop();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 /*
-- 
2.33.1

[PATCH v5 08/21] arm64: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/arm64/kernel/process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index aacf2f5559a8..f8db031afa7d 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -110,8 +110,7 @@ void machine_power_off(void)
 {
 	local_irq_disable();
 	smp_send_stop();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 /*
-- 
2.33.1

[PATCH v5 08/21] arm64: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/arm64/kernel/process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index aacf2f5559a8..f8db031afa7d 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -110,8 +110,7 @@ void machine_power_off(void)
 {
 	local_irq_disable();
 	smp_send_stop();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 /*
-- 
2.33.1

[PATCH v5 09/21] parisc: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/parisc/kernel/process.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index ea3d83b6fb62..928201b1f58f 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -26,6 +26,7 @@
 #include <linux/module.h>
 #include <linux/personality.h>
 #include <linux/ptrace.h>
+#include <linux/reboot.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/task.h>
@@ -114,8 +115,7 @@ void machine_power_off(void)
 	pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 
 	/* ipmi_poweroff may have been installed. */
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 		
 	/* It seems we have no way to power the system off via
 	 * software. The user has to press the button himself. */
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 09/21] parisc: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/parisc/kernel/process.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index ea3d83b6fb62..928201b1f58f 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -26,6 +26,7 @@
 #include <linux/module.h>
 #include <linux/personality.h>
 #include <linux/ptrace.h>
+#include <linux/reboot.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/task.h>
@@ -114,8 +115,7 @@ void machine_power_off(void)
 	pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 
 	/* ipmi_poweroff may have been installed. */
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 		
 	/* It seems we have no way to power the system off via
 	 * software. The user has to press the button himself. */
-- 
2.33.1

[PATCH v5 09/21] parisc: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/parisc/kernel/process.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index ea3d83b6fb62..928201b1f58f 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -26,6 +26,7 @@
 #include <linux/module.h>
 #include <linux/personality.h>
 #include <linux/ptrace.h>
+#include <linux/reboot.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/task.h>
@@ -114,8 +115,7 @@ void machine_power_off(void)
 	pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 
 	/* ipmi_poweroff may have been installed. */
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 		
 	/* It seems we have no way to power the system off via
 	 * software. The user has to press the button himself. */
-- 
2.33.1

[PATCH v5 09/21] parisc: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/parisc/kernel/process.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index ea3d83b6fb62..928201b1f58f 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -26,6 +26,7 @@
 #include <linux/module.h>
 #include <linux/personality.h>
 #include <linux/ptrace.h>
+#include <linux/reboot.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/task.h>
@@ -114,8 +115,7 @@ void machine_power_off(void)
 	pdc_chassis_send_status(PDC_CHASSIS_DIRECT_SHUTDOWN);
 
 	/* ipmi_poweroff may have been installed. */
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 		
 	/* It seems we have no way to power the system off via
 	 * software. The user has to press the button himself. */
-- 
2.33.1

[PATCH v5 10/21] xen/x86: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/x86/xen/enlighten_pv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 5004feb16783..527fa545eb1f 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -31,6 +31,7 @@
 #include <linux/gfp.h>
 #include <linux/edd.h>
 #include <linux/objtool.h>
+#include <linux/reboot.h>
 
 #include <xen/xen.h>
 #include <xen/events.h>
@@ -1068,8 +1069,7 @@ static void xen_machine_halt(void)
 
 static void xen_machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	xen_reboot(SHUTDOWN_poweroff);
 }
 
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 10/21] xen/x86: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/x86/xen/enlighten_pv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 5004feb16783..527fa545eb1f 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -31,6 +31,7 @@
 #include <linux/gfp.h>
 #include <linux/edd.h>
 #include <linux/objtool.h>
+#include <linux/reboot.h>
 
 #include <xen/xen.h>
 #include <xen/events.h>
@@ -1068,8 +1069,7 @@ static void xen_machine_halt(void)
 
 static void xen_machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	xen_reboot(SHUTDOWN_poweroff);
 }
 
-- 
2.33.1

[PATCH v5 10/21] xen/x86: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/x86/xen/enlighten_pv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 5004feb16783..527fa545eb1f 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -31,6 +31,7 @@
 #include <linux/gfp.h>
 #include <linux/edd.h>
 #include <linux/objtool.h>
+#include <linux/reboot.h>
 
 #include <xen/xen.h>
 #include <xen/events.h>
@@ -1068,8 +1069,7 @@ static void xen_machine_halt(void)
 
 static void xen_machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	xen_reboot(SHUTDOWN_poweroff);
 }
 
-- 
2.33.1

[PATCH v5 10/21] xen/x86: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/x86/xen/enlighten_pv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 5004feb16783..527fa545eb1f 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -31,6 +31,7 @@
 #include <linux/gfp.h>
 #include <linux/edd.h>
 #include <linux/objtool.h>
+#include <linux/reboot.h>
 
 #include <xen/xen.h>
 #include <xen/events.h>
@@ -1068,8 +1069,7 @@ static void xen_machine_halt(void)
 
 static void xen_machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	xen_reboot(SHUTDOWN_poweroff);
 }
 
-- 
2.33.1

[PATCH v5 11/21] powerpc: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/powerpc/kernel/setup-common.c | 4 +---
 arch/powerpc/xmon/xmon.c           | 3 +--
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index f8da937df918..8158e940db81 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -161,9 +161,7 @@ void machine_restart(char *cmd)
 void machine_power_off(void)
 {
 	machine_shutdown();
-	if (pm_power_off)
-		pm_power_off();
-
+	do_kernel_power_off();
 	smp_send_stop();
 	machine_hang();
 }
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 83100c6524cc..759e167704e6 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1243,8 +1243,7 @@ static void bootcmds(void)
 	} else if (cmd == 'h') {
 		ppc_md.halt();
 	} else if (cmd == 'p') {
-		if (pm_power_off)
-			pm_power_off();
+		do_kernel_power_off();
 	}
 }
 
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 11/21] powerpc: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/powerpc/kernel/setup-common.c | 4 +---
 arch/powerpc/xmon/xmon.c           | 3 +--
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index f8da937df918..8158e940db81 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -161,9 +161,7 @@ void machine_restart(char *cmd)
 void machine_power_off(void)
 {
 	machine_shutdown();
-	if (pm_power_off)
-		pm_power_off();
-
+	do_kernel_power_off();
 	smp_send_stop();
 	machine_hang();
 }
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 83100c6524cc..759e167704e6 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1243,8 +1243,7 @@ static void bootcmds(void)
 	} else if (cmd == 'h') {
 		ppc_md.halt();
 	} else if (cmd == 'p') {
-		if (pm_power_off)
-			pm_power_off();
+		do_kernel_power_off();
 	}
 }
 
-- 
2.33.1

[PATCH v5 11/21] powerpc: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/powerpc/kernel/setup-common.c | 4 +---
 arch/powerpc/xmon/xmon.c           | 3 +--
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index f8da937df918..8158e940db81 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -161,9 +161,7 @@ void machine_restart(char *cmd)
 void machine_power_off(void)
 {
 	machine_shutdown();
-	if (pm_power_off)
-		pm_power_off();
-
+	do_kernel_power_off();
 	smp_send_stop();
 	machine_hang();
 }
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 83100c6524cc..759e167704e6 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1243,8 +1243,7 @@ static void bootcmds(void)
 	} else if (cmd == 'h') {
 		ppc_md.halt();
 	} else if (cmd == 'p') {
-		if (pm_power_off)
-			pm_power_off();
+		do_kernel_power_off();
 	}
 }
 
-- 
2.33.1

[PATCH v5 11/21] powerpc: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/powerpc/kernel/setup-common.c | 4 +---
 arch/powerpc/xmon/xmon.c           | 3 +--
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index f8da937df918..8158e940db81 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -161,9 +161,7 @@ void machine_restart(char *cmd)
 void machine_power_off(void)
 {
 	machine_shutdown();
-	if (pm_power_off)
-		pm_power_off();
-
+	do_kernel_power_off();
 	smp_send_stop();
 	machine_hang();
 }
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 83100c6524cc..759e167704e6 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1243,8 +1243,7 @@ static void bootcmds(void)
 	} else if (cmd = 'h') {
 		ppc_md.halt();
 	} else if (cmd = 'p') {
-		if (pm_power_off)
-			pm_power_off();
+		do_kernel_power_off();
 	}
 }
 
-- 
2.33.1

[PATCH v5 12/21] m68k: Switch to new sys-off handler API

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use
register_power_off_handler() that registers power-off handlers and
do_kernel_power_off() that invokes chained power-off handlers. Legacy
pm_power_off() will be removed once all drivers will be converted to
the new power-off API.

Normally arch code should adopt only the do_kernel_power_off() at first,
but m68k is a special case because it uses pm_power_off() "inside out",
i.e. pm_power_off() invokes machine_power_off() [in fact it does nothing],
while it's machine_power_off() that should invoke the pm_power_off(), and
thus, we can't convert platforms to the new API separately. There are only
two platforms changed here, so it's not a big deal.

Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/m68k/emu/natfeat.c         | 3 ++-
 arch/m68k/include/asm/machdep.h | 1 -
 arch/m68k/kernel/process.c      | 5 ++---
 arch/m68k/kernel/setup_mm.c     | 1 -
 arch/m68k/kernel/setup_no.c     | 1 -
 arch/m68k/mac/config.c          | 4 +++-
 6 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/arch/m68k/emu/natfeat.c b/arch/m68k/emu/natfeat.c
index 71b78ecee75c..b19dc00026d9 100644
--- a/arch/m68k/emu/natfeat.c
+++ b/arch/m68k/emu/natfeat.c
@@ -15,6 +15,7 @@
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/reboot.h>
 #include <linux/io.h>
 #include <asm/machdep.h>
 #include <asm/natfeat.h>
@@ -90,5 +91,5 @@ void __init nf_init(void)
 	pr_info("NatFeats found (%s, %lu.%lu)\n", buf, version >> 16,
 		version & 0xffff);
 
-	mach_power_off = nf_poweroff;
+	register_platform_power_off(nf_poweroff);
 }
diff --git a/arch/m68k/include/asm/machdep.h b/arch/m68k/include/asm/machdep.h
index 8fd80ef1b77e..8d8c3ee2069f 100644
--- a/arch/m68k/include/asm/machdep.h
+++ b/arch/m68k/include/asm/machdep.h
@@ -24,7 +24,6 @@ extern int (*mach_get_rtc_pll)(struct rtc_pll_info *);
 extern int (*mach_set_rtc_pll)(struct rtc_pll_info *);
 extern void (*mach_reset)( void );
 extern void (*mach_halt)( void );
-extern void (*mach_power_off)( void );
 extern unsigned long (*mach_hd_init) (unsigned long, unsigned long);
 extern void (*mach_hd_setup)(char *, int *);
 extern void (*mach_heartbeat) (int);
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index a6030dbaa089..e160a7c57bd3 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -67,12 +67,11 @@ void machine_halt(void)
 
 void machine_power_off(void)
 {
-	if (mach_power_off)
-		mach_power_off();
+	do_kernel_power_off();
 	for (;;);
 }
 
-void (*pm_power_off)(void) = machine_power_off;
+void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
 void show_regs(struct pt_regs * regs)
diff --git a/arch/m68k/kernel/setup_mm.c b/arch/m68k/kernel/setup_mm.c
index 49e573b94326..a3ff1342ced7 100644
--- a/arch/m68k/kernel/setup_mm.c
+++ b/arch/m68k/kernel/setup_mm.c
@@ -98,7 +98,6 @@ EXPORT_SYMBOL(mach_get_rtc_pll);
 EXPORT_SYMBOL(mach_set_rtc_pll);
 void (*mach_reset)( void );
 void (*mach_halt)( void );
-void (*mach_power_off)( void );
 #ifdef CONFIG_HEARTBEAT
 void (*mach_heartbeat) (int);
 EXPORT_SYMBOL(mach_heartbeat);
diff --git a/arch/m68k/kernel/setup_no.c b/arch/m68k/kernel/setup_no.c
index 5e4104f07a44..00bf82258233 100644
--- a/arch/m68k/kernel/setup_no.c
+++ b/arch/m68k/kernel/setup_no.c
@@ -55,7 +55,6 @@ int (*mach_hwclk) (int, struct rtc_time*);
 /* machine dependent reboot functions */
 void (*mach_reset)(void);
 void (*mach_halt)(void);
-void (*mach_power_off)(void);
 
 #ifdef CONFIG_M68000
 #if defined(CONFIG_M68328)
diff --git a/arch/m68k/mac/config.c b/arch/m68k/mac/config.c
index 5d16f9b47aa9..727320dedf08 100644
--- a/arch/m68k/mac/config.c
+++ b/arch/m68k/mac/config.c
@@ -12,6 +12,7 @@
 
 #include <linux/errno.h>
 #include <linux/module.h>
+#include <linux/reboot.h>
 #include <linux/types.h>
 #include <linux/mm.h>
 #include <linux/tty.h>
@@ -139,7 +140,6 @@ void __init config_mac(void)
 	mach_hwclk = mac_hwclk;
 	mach_reset = mac_reset;
 	mach_halt = mac_poweroff;
-	mach_power_off = mac_poweroff;
 #if IS_ENABLED(CONFIG_INPUT_M68K_BEEP)
 	mach_beep = mac_mksound;
 #endif
@@ -159,6 +159,8 @@ void __init config_mac(void)
 
 	if (macintosh_config->ident == MAC_MODEL_IICI)
 		mach_l2_flush = via_l2_flush;
+
+	register_platform_power_off(mac_poweroff);
 }
 
 
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 12/21] m68k: Switch to new sys-off handler API

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use
register_power_off_handler() that registers power-off handlers and
do_kernel_power_off() that invokes chained power-off handlers. Legacy
pm_power_off() will be removed once all drivers will be converted to
the new power-off API.

Normally arch code should adopt only the do_kernel_power_off() at first,
but m68k is a special case because it uses pm_power_off() "inside out",
i.e. pm_power_off() invokes machine_power_off() [in fact it does nothing],
while it's machine_power_off() that should invoke the pm_power_off(), and
thus, we can't convert platforms to the new API separately. There are only
two platforms changed here, so it's not a big deal.

Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/m68k/emu/natfeat.c         | 3 ++-
 arch/m68k/include/asm/machdep.h | 1 -
 arch/m68k/kernel/process.c      | 5 ++---
 arch/m68k/kernel/setup_mm.c     | 1 -
 arch/m68k/kernel/setup_no.c     | 1 -
 arch/m68k/mac/config.c          | 4 +++-
 6 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/arch/m68k/emu/natfeat.c b/arch/m68k/emu/natfeat.c
index 71b78ecee75c..b19dc00026d9 100644
--- a/arch/m68k/emu/natfeat.c
+++ b/arch/m68k/emu/natfeat.c
@@ -15,6 +15,7 @@
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/reboot.h>
 #include <linux/io.h>
 #include <asm/machdep.h>
 #include <asm/natfeat.h>
@@ -90,5 +91,5 @@ void __init nf_init(void)
 	pr_info("NatFeats found (%s, %lu.%lu)\n", buf, version >> 16,
 		version & 0xffff);
 
-	mach_power_off = nf_poweroff;
+	register_platform_power_off(nf_poweroff);
 }
diff --git a/arch/m68k/include/asm/machdep.h b/arch/m68k/include/asm/machdep.h
index 8fd80ef1b77e..8d8c3ee2069f 100644
--- a/arch/m68k/include/asm/machdep.h
+++ b/arch/m68k/include/asm/machdep.h
@@ -24,7 +24,6 @@ extern int (*mach_get_rtc_pll)(struct rtc_pll_info *);
 extern int (*mach_set_rtc_pll)(struct rtc_pll_info *);
 extern void (*mach_reset)( void );
 extern void (*mach_halt)( void );
-extern void (*mach_power_off)( void );
 extern unsigned long (*mach_hd_init) (unsigned long, unsigned long);
 extern void (*mach_hd_setup)(char *, int *);
 extern void (*mach_heartbeat) (int);
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index a6030dbaa089..e160a7c57bd3 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -67,12 +67,11 @@ void machine_halt(void)
 
 void machine_power_off(void)
 {
-	if (mach_power_off)
-		mach_power_off();
+	do_kernel_power_off();
 	for (;;);
 }
 
-void (*pm_power_off)(void) = machine_power_off;
+void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
 void show_regs(struct pt_regs * regs)
diff --git a/arch/m68k/kernel/setup_mm.c b/arch/m68k/kernel/setup_mm.c
index 49e573b94326..a3ff1342ced7 100644
--- a/arch/m68k/kernel/setup_mm.c
+++ b/arch/m68k/kernel/setup_mm.c
@@ -98,7 +98,6 @@ EXPORT_SYMBOL(mach_get_rtc_pll);
 EXPORT_SYMBOL(mach_set_rtc_pll);
 void (*mach_reset)( void );
 void (*mach_halt)( void );
-void (*mach_power_off)( void );
 #ifdef CONFIG_HEARTBEAT
 void (*mach_heartbeat) (int);
 EXPORT_SYMBOL(mach_heartbeat);
diff --git a/arch/m68k/kernel/setup_no.c b/arch/m68k/kernel/setup_no.c
index 5e4104f07a44..00bf82258233 100644
--- a/arch/m68k/kernel/setup_no.c
+++ b/arch/m68k/kernel/setup_no.c
@@ -55,7 +55,6 @@ int (*mach_hwclk) (int, struct rtc_time*);
 /* machine dependent reboot functions */
 void (*mach_reset)(void);
 void (*mach_halt)(void);
-void (*mach_power_off)(void);
 
 #ifdef CONFIG_M68000
 #if defined(CONFIG_M68328)
diff --git a/arch/m68k/mac/config.c b/arch/m68k/mac/config.c
index 5d16f9b47aa9..727320dedf08 100644
--- a/arch/m68k/mac/config.c
+++ b/arch/m68k/mac/config.c
@@ -12,6 +12,7 @@
 
 #include <linux/errno.h>
 #include <linux/module.h>
+#include <linux/reboot.h>
 #include <linux/types.h>
 #include <linux/mm.h>
 #include <linux/tty.h>
@@ -139,7 +140,6 @@ void __init config_mac(void)
 	mach_hwclk = mac_hwclk;
 	mach_reset = mac_reset;
 	mach_halt = mac_poweroff;
-	mach_power_off = mac_poweroff;
 #if IS_ENABLED(CONFIG_INPUT_M68K_BEEP)
 	mach_beep = mac_mksound;
 #endif
@@ -159,6 +159,8 @@ void __init config_mac(void)
 
 	if (macintosh_config->ident == MAC_MODEL_IICI)
 		mach_l2_flush = via_l2_flush;
+
+	register_platform_power_off(mac_poweroff);
 }
 
 
-- 
2.33.1

[PATCH v5 12/21] m68k: Switch to new sys-off handler API

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use
register_power_off_handler() that registers power-off handlers and
do_kernel_power_off() that invokes chained power-off handlers. Legacy
pm_power_off() will be removed once all drivers will be converted to
the new power-off API.

Normally arch code should adopt only the do_kernel_power_off() at first,
but m68k is a special case because it uses pm_power_off() "inside out",
i.e. pm_power_off() invokes machine_power_off() [in fact it does nothing],
while it's machine_power_off() that should invoke the pm_power_off(), and
thus, we can't convert platforms to the new API separately. There are only
two platforms changed here, so it's not a big deal.

Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/m68k/emu/natfeat.c         | 3 ++-
 arch/m68k/include/asm/machdep.h | 1 -
 arch/m68k/kernel/process.c      | 5 ++---
 arch/m68k/kernel/setup_mm.c     | 1 -
 arch/m68k/kernel/setup_no.c     | 1 -
 arch/m68k/mac/config.c          | 4 +++-
 6 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/arch/m68k/emu/natfeat.c b/arch/m68k/emu/natfeat.c
index 71b78ecee75c..b19dc00026d9 100644
--- a/arch/m68k/emu/natfeat.c
+++ b/arch/m68k/emu/natfeat.c
@@ -15,6 +15,7 @@
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/reboot.h>
 #include <linux/io.h>
 #include <asm/machdep.h>
 #include <asm/natfeat.h>
@@ -90,5 +91,5 @@ void __init nf_init(void)
 	pr_info("NatFeats found (%s, %lu.%lu)\n", buf, version >> 16,
 		version & 0xffff);
 
-	mach_power_off = nf_poweroff;
+	register_platform_power_off(nf_poweroff);
 }
diff --git a/arch/m68k/include/asm/machdep.h b/arch/m68k/include/asm/machdep.h
index 8fd80ef1b77e..8d8c3ee2069f 100644
--- a/arch/m68k/include/asm/machdep.h
+++ b/arch/m68k/include/asm/machdep.h
@@ -24,7 +24,6 @@ extern int (*mach_get_rtc_pll)(struct rtc_pll_info *);
 extern int (*mach_set_rtc_pll)(struct rtc_pll_info *);
 extern void (*mach_reset)( void );
 extern void (*mach_halt)( void );
-extern void (*mach_power_off)( void );
 extern unsigned long (*mach_hd_init) (unsigned long, unsigned long);
 extern void (*mach_hd_setup)(char *, int *);
 extern void (*mach_heartbeat) (int);
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index a6030dbaa089..e160a7c57bd3 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -67,12 +67,11 @@ void machine_halt(void)
 
 void machine_power_off(void)
 {
-	if (mach_power_off)
-		mach_power_off();
+	do_kernel_power_off();
 	for (;;);
 }
 
-void (*pm_power_off)(void) = machine_power_off;
+void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
 void show_regs(struct pt_regs * regs)
diff --git a/arch/m68k/kernel/setup_mm.c b/arch/m68k/kernel/setup_mm.c
index 49e573b94326..a3ff1342ced7 100644
--- a/arch/m68k/kernel/setup_mm.c
+++ b/arch/m68k/kernel/setup_mm.c
@@ -98,7 +98,6 @@ EXPORT_SYMBOL(mach_get_rtc_pll);
 EXPORT_SYMBOL(mach_set_rtc_pll);
 void (*mach_reset)( void );
 void (*mach_halt)( void );
-void (*mach_power_off)( void );
 #ifdef CONFIG_HEARTBEAT
 void (*mach_heartbeat) (int);
 EXPORT_SYMBOL(mach_heartbeat);
diff --git a/arch/m68k/kernel/setup_no.c b/arch/m68k/kernel/setup_no.c
index 5e4104f07a44..00bf82258233 100644
--- a/arch/m68k/kernel/setup_no.c
+++ b/arch/m68k/kernel/setup_no.c
@@ -55,7 +55,6 @@ int (*mach_hwclk) (int, struct rtc_time*);
 /* machine dependent reboot functions */
 void (*mach_reset)(void);
 void (*mach_halt)(void);
-void (*mach_power_off)(void);
 
 #ifdef CONFIG_M68000
 #if defined(CONFIG_M68328)
diff --git a/arch/m68k/mac/config.c b/arch/m68k/mac/config.c
index 5d16f9b47aa9..727320dedf08 100644
--- a/arch/m68k/mac/config.c
+++ b/arch/m68k/mac/config.c
@@ -12,6 +12,7 @@
 
 #include <linux/errno.h>
 #include <linux/module.h>
+#include <linux/reboot.h>
 #include <linux/types.h>
 #include <linux/mm.h>
 #include <linux/tty.h>
@@ -139,7 +140,6 @@ void __init config_mac(void)
 	mach_hwclk = mac_hwclk;
 	mach_reset = mac_reset;
 	mach_halt = mac_poweroff;
-	mach_power_off = mac_poweroff;
 #if IS_ENABLED(CONFIG_INPUT_M68K_BEEP)
 	mach_beep = mac_mksound;
 #endif
@@ -159,6 +159,8 @@ void __init config_mac(void)
 
 	if (macintosh_config->ident == MAC_MODEL_IICI)
 		mach_l2_flush = via_l2_flush;
+
+	register_platform_power_off(mac_poweroff);
 }
 
 
-- 
2.33.1

[PATCH v5 12/21] m68k: Switch to new sys-off handler API

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use
register_power_off_handler() that registers power-off handlers and
do_kernel_power_off() that invokes chained power-off handlers. Legacy
pm_power_off() will be removed once all drivers will be converted to
the new power-off API.

Normally arch code should adopt only the do_kernel_power_off() at first,
but m68k is a special case because it uses pm_power_off() "inside out",
i.e. pm_power_off() invokes machine_power_off() [in fact it does nothing],
while it's machine_power_off() that should invoke the pm_power_off(), and
thus, we can't convert platforms to the new API separately. There are only
two platforms changed here, so it's not a big deal.

Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/m68k/emu/natfeat.c         | 3 ++-
 arch/m68k/include/asm/machdep.h | 1 -
 arch/m68k/kernel/process.c      | 5 ++---
 arch/m68k/kernel/setup_mm.c     | 1 -
 arch/m68k/kernel/setup_no.c     | 1 -
 arch/m68k/mac/config.c          | 4 +++-
 6 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/arch/m68k/emu/natfeat.c b/arch/m68k/emu/natfeat.c
index 71b78ecee75c..b19dc00026d9 100644
--- a/arch/m68k/emu/natfeat.c
+++ b/arch/m68k/emu/natfeat.c
@@ -15,6 +15,7 @@
 #include <linux/string.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/reboot.h>
 #include <linux/io.h>
 #include <asm/machdep.h>
 #include <asm/natfeat.h>
@@ -90,5 +91,5 @@ void __init nf_init(void)
 	pr_info("NatFeats found (%s, %lu.%lu)\n", buf, version >> 16,
 		version & 0xffff);
 
-	mach_power_off = nf_poweroff;
+	register_platform_power_off(nf_poweroff);
 }
diff --git a/arch/m68k/include/asm/machdep.h b/arch/m68k/include/asm/machdep.h
index 8fd80ef1b77e..8d8c3ee2069f 100644
--- a/arch/m68k/include/asm/machdep.h
+++ b/arch/m68k/include/asm/machdep.h
@@ -24,7 +24,6 @@ extern int (*mach_get_rtc_pll)(struct rtc_pll_info *);
 extern int (*mach_set_rtc_pll)(struct rtc_pll_info *);
 extern void (*mach_reset)( void );
 extern void (*mach_halt)( void );
-extern void (*mach_power_off)( void );
 extern unsigned long (*mach_hd_init) (unsigned long, unsigned long);
 extern void (*mach_hd_setup)(char *, int *);
 extern void (*mach_heartbeat) (int);
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index a6030dbaa089..e160a7c57bd3 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -67,12 +67,11 @@ void machine_halt(void)
 
 void machine_power_off(void)
 {
-	if (mach_power_off)
-		mach_power_off();
+	do_kernel_power_off();
 	for (;;);
 }
 
-void (*pm_power_off)(void) = machine_power_off;
+void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
 void show_regs(struct pt_regs * regs)
diff --git a/arch/m68k/kernel/setup_mm.c b/arch/m68k/kernel/setup_mm.c
index 49e573b94326..a3ff1342ced7 100644
--- a/arch/m68k/kernel/setup_mm.c
+++ b/arch/m68k/kernel/setup_mm.c
@@ -98,7 +98,6 @@ EXPORT_SYMBOL(mach_get_rtc_pll);
 EXPORT_SYMBOL(mach_set_rtc_pll);
 void (*mach_reset)( void );
 void (*mach_halt)( void );
-void (*mach_power_off)( void );
 #ifdef CONFIG_HEARTBEAT
 void (*mach_heartbeat) (int);
 EXPORT_SYMBOL(mach_heartbeat);
diff --git a/arch/m68k/kernel/setup_no.c b/arch/m68k/kernel/setup_no.c
index 5e4104f07a44..00bf82258233 100644
--- a/arch/m68k/kernel/setup_no.c
+++ b/arch/m68k/kernel/setup_no.c
@@ -55,7 +55,6 @@ int (*mach_hwclk) (int, struct rtc_time*);
 /* machine dependent reboot functions */
 void (*mach_reset)(void);
 void (*mach_halt)(void);
-void (*mach_power_off)(void);
 
 #ifdef CONFIG_M68000
 #if defined(CONFIG_M68328)
diff --git a/arch/m68k/mac/config.c b/arch/m68k/mac/config.c
index 5d16f9b47aa9..727320dedf08 100644
--- a/arch/m68k/mac/config.c
+++ b/arch/m68k/mac/config.c
@@ -12,6 +12,7 @@
 
 #include <linux/errno.h>
 #include <linux/module.h>
+#include <linux/reboot.h>
 #include <linux/types.h>
 #include <linux/mm.h>
 #include <linux/tty.h>
@@ -139,7 +140,6 @@ void __init config_mac(void)
 	mach_hwclk = mac_hwclk;
 	mach_reset = mac_reset;
 	mach_halt = mac_poweroff;
-	mach_power_off = mac_poweroff;
 #if IS_ENABLED(CONFIG_INPUT_M68K_BEEP)
 	mach_beep = mac_mksound;
 #endif
@@ -159,6 +159,8 @@ void __init config_mac(void)
 
 	if (macintosh_config->ident = MAC_MODEL_IICI)
 		mach_l2_flush = via_l2_flush;
+
+	register_platform_power_off(mac_poweroff);
 }
 
 
-- 
2.33.1

[PATCH v5 13/21] sh: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/sh/kernel/reboot.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/sh/kernel/reboot.c b/arch/sh/kernel/reboot.c
index 5c33f036418b..e8eeedc9b182 100644
--- a/arch/sh/kernel/reboot.c
+++ b/arch/sh/kernel/reboot.c
@@ -46,8 +46,7 @@ static void native_machine_shutdown(void)
 
 static void native_machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 static void native_machine_halt(void)
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 13/21] sh: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/sh/kernel/reboot.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/sh/kernel/reboot.c b/arch/sh/kernel/reboot.c
index 5c33f036418b..e8eeedc9b182 100644
--- a/arch/sh/kernel/reboot.c
+++ b/arch/sh/kernel/reboot.c
@@ -46,8 +46,7 @@ static void native_machine_shutdown(void)
 
 static void native_machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 static void native_machine_halt(void)
-- 
2.33.1

[PATCH v5 13/21] sh: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/sh/kernel/reboot.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/sh/kernel/reboot.c b/arch/sh/kernel/reboot.c
index 5c33f036418b..e8eeedc9b182 100644
--- a/arch/sh/kernel/reboot.c
+++ b/arch/sh/kernel/reboot.c
@@ -46,8 +46,7 @@ static void native_machine_shutdown(void)
 
 static void native_machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 static void native_machine_halt(void)
-- 
2.33.1

[PATCH v5 13/21] sh: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/sh/kernel/reboot.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/sh/kernel/reboot.c b/arch/sh/kernel/reboot.c
index 5c33f036418b..e8eeedc9b182 100644
--- a/arch/sh/kernel/reboot.c
+++ b/arch/sh/kernel/reboot.c
@@ -46,8 +46,7 @@ static void native_machine_shutdown(void)
 
 static void native_machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 static void native_machine_halt(void)
-- 
2.33.1

[PATCH v5 14/21] x86: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/x86/kernel/reboot.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index fa700b46588e..c3636ea4aa71 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -739,10 +739,10 @@ static void native_machine_halt(void)
 
 static void native_machine_power_off(void)
 {
-	if (pm_power_off) {
+	if (kernel_can_power_off()) {
 		if (!reboot_force)
 			machine_shutdown();
-		pm_power_off();
+		do_kernel_power_off();
 	}
 	/* A fallback in case there is no PM info available */
 	tboot_shutdown(TB_SHUTDOWN_HALT);
-- 
2.33.1


_______________________________________________
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 14/21] x86: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/x86/kernel/reboot.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index fa700b46588e..c3636ea4aa71 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -739,10 +739,10 @@ static void native_machine_halt(void)
 
 static void native_machine_power_off(void)
 {
-	if (pm_power_off) {
+	if (kernel_can_power_off()) {
 		if (!reboot_force)
 			machine_shutdown();
-		pm_power_off();
+		do_kernel_power_off();
 	}
 	/* A fallback in case there is no PM info available */
 	tboot_shutdown(TB_SHUTDOWN_HALT);
-- 
2.33.1

[PATCH v5 14/21] x86: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/x86/kernel/reboot.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index fa700b46588e..c3636ea4aa71 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -739,10 +739,10 @@ static void native_machine_halt(void)
 
 static void native_machine_power_off(void)
 {
-	if (pm_power_off) {
+	if (kernel_can_power_off()) {
 		if (!reboot_force)
 			machine_shutdown();
-		pm_power_off();
+		do_kernel_power_off();
 	}
 	/* A fallback in case there is no PM info available */
 	tboot_shutdown(TB_SHUTDOWN_HALT);
-- 
2.33.1

[PATCH v5 14/21] x86: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/x86/kernel/reboot.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index fa700b46588e..c3636ea4aa71 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -739,10 +739,10 @@ static void native_machine_halt(void)
 
 static void native_machine_power_off(void)
 {
-	if (pm_power_off) {
+	if (kernel_can_power_off()) {
 		if (!reboot_force)
 			machine_shutdown();
-		pm_power_off();
+		do_kernel_power_off();
 	}
 	/* A fallback in case there is no PM info available */
 	tboot_shutdown(TB_SHUTDOWN_HALT);
-- 
2.33.1

[PATCH v5 15/21] ia64: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/ia64/kernel/process.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 834df24a88f1..cee4d7db2143 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/notifier.h>
 #include <linux/personality.h>
+#include <linux/reboot.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/hotplug.h>
@@ -599,8 +600,7 @@ machine_halt (void)
 void
 machine_power_off (void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	machine_halt();
 }
 
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 15/21] ia64: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/ia64/kernel/process.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 834df24a88f1..cee4d7db2143 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/notifier.h>
 #include <linux/personality.h>
+#include <linux/reboot.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/hotplug.h>
@@ -599,8 +600,7 @@ machine_halt (void)
 void
 machine_power_off (void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	machine_halt();
 }
 
-- 
2.33.1

[PATCH v5 15/21] ia64: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/ia64/kernel/process.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 834df24a88f1..cee4d7db2143 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/notifier.h>
 #include <linux/personality.h>
+#include <linux/reboot.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/hotplug.h>
@@ -599,8 +600,7 @@ machine_halt (void)
 void
 machine_power_off (void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	machine_halt();
 }
 
-- 
2.33.1

[PATCH v5 15/21] ia64: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/ia64/kernel/process.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 834df24a88f1..cee4d7db2143 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/notifier.h>
 #include <linux/personality.h>
+#include <linux/reboot.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/hotplug.h>
@@ -599,8 +600,7 @@ machine_halt (void)
 void
 machine_power_off (void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 	machine_halt();
 }
 
-- 
2.33.1

[PATCH v5 16/21] mips: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/mips/kernel/reset.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/mips/kernel/reset.c b/arch/mips/kernel/reset.c
index 6288780b779e..e7ce07b3e79b 100644
--- a/arch/mips/kernel/reset.c
+++ b/arch/mips/kernel/reset.c
@@ -114,8 +114,7 @@ void machine_halt(void)
 
 void machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 
 #ifdef CONFIG_SMP
 	preempt_disable();
-- 
2.33.1


_______________________________________________
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 16/21] mips: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/mips/kernel/reset.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/mips/kernel/reset.c b/arch/mips/kernel/reset.c
index 6288780b779e..e7ce07b3e79b 100644
--- a/arch/mips/kernel/reset.c
+++ b/arch/mips/kernel/reset.c
@@ -114,8 +114,7 @@ void machine_halt(void)
 
 void machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 
 #ifdef CONFIG_SMP
 	preempt_disable();
-- 
2.33.1

[PATCH v5 16/21] mips: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/mips/kernel/reset.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/mips/kernel/reset.c b/arch/mips/kernel/reset.c
index 6288780b779e..e7ce07b3e79b 100644
--- a/arch/mips/kernel/reset.c
+++ b/arch/mips/kernel/reset.c
@@ -114,8 +114,7 @@ void machine_halt(void)
 
 void machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 
 #ifdef CONFIG_SMP
 	preempt_disable();
-- 
2.33.1

[PATCH v5 16/21] mips: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/mips/kernel/reset.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/mips/kernel/reset.c b/arch/mips/kernel/reset.c
index 6288780b779e..e7ce07b3e79b 100644
--- a/arch/mips/kernel/reset.c
+++ b/arch/mips/kernel/reset.c
@@ -114,8 +114,7 @@ void machine_halt(void)
 
 void machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 
 #ifdef CONFIG_SMP
 	preempt_disable();
-- 
2.33.1

[PATCH v5 17/21] nds32: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/nds32/kernel/process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/nds32/kernel/process.c b/arch/nds32/kernel/process.c
index 49fab9e39cbf..0936dcd7db1b 100644
--- a/arch/nds32/kernel/process.c
+++ b/arch/nds32/kernel/process.c
@@ -54,8 +54,7 @@ EXPORT_SYMBOL(machine_halt);
 
 void machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 EXPORT_SYMBOL(machine_power_off);
-- 
2.33.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 17/21] nds32: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/nds32/kernel/process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/nds32/kernel/process.c b/arch/nds32/kernel/process.c
index 49fab9e39cbf..0936dcd7db1b 100644
--- a/arch/nds32/kernel/process.c
+++ b/arch/nds32/kernel/process.c
@@ -54,8 +54,7 @@ EXPORT_SYMBOL(machine_halt);
 
 void machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 EXPORT_SYMBOL(machine_power_off);
-- 
2.33.1

[PATCH v5 17/21] nds32: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/nds32/kernel/process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/nds32/kernel/process.c b/arch/nds32/kernel/process.c
index 49fab9e39cbf..0936dcd7db1b 100644
--- a/arch/nds32/kernel/process.c
+++ b/arch/nds32/kernel/process.c
@@ -54,8 +54,7 @@ EXPORT_SYMBOL(machine_halt);
 
 void machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 EXPORT_SYMBOL(machine_power_off);
-- 
2.33.1

[PATCH v5 17/21] nds32: Use do_kernel_power_off()

[Dmitry Osipenko]

Kernel now supports chained power-off handlers. Use do_kernel_power_off()
that invokes chained power-off handlers. It also invokes legacy
pm_power_off() for now, which will be removed once all drivers will
be converted to the new power-off API.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/nds32/kernel/process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/nds32/kernel/process.c b/arch/nds32/kernel/process.c
index 49fab9e39cbf..0936dcd7db1b 100644
--- a/arch/nds32/kernel/process.c
+++ b/arch/nds32/kernel/process.c
@@ -54,8 +54,7 @@ EXPORT_SYMBOL(machine_halt);
 
 void machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 EXPORT_SYMBOL(machine_power_off);
-- 
2.33.1

[PATCH v5 18/21] memory: emif: Use kernel_can_power_off()

[Dmitry Osipenko]

Replace legacy pm_power_off with kernel_can_power_off() helper that
is aware about chained power-off handlers.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/memory/emif.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index 762d0c0f0716..cab10d5274a0 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -630,7 +630,7 @@ static irqreturn_t emif_threaded_isr(int irq, void *dev_id)
 		dev_emerg(emif->dev, "SDRAM temperature exceeds operating limit.. Needs shut down!!!\n");
 
 		/* If we have Power OFF ability, use it, else try restarting */
-		if (pm_power_off) {
+		if (kernel_can_power_off()) {
 			kernel_power_off();
 		} else {
 			WARN(1, "FIXME: NO pm_power_off!!! trying restart\n");
-- 
2.33.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 18/21] memory: emif: Use kernel_can_power_off()

[Dmitry Osipenko]

Replace legacy pm_power_off with kernel_can_power_off() helper that
is aware about chained power-off handlers.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/memory/emif.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index 762d0c0f0716..cab10d5274a0 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -630,7 +630,7 @@ static irqreturn_t emif_threaded_isr(int irq, void *dev_id)
 		dev_emerg(emif->dev, "SDRAM temperature exceeds operating limit.. Needs shut down!!!\n");
 
 		/* If we have Power OFF ability, use it, else try restarting */
-		if (pm_power_off) {
+		if (kernel_can_power_off()) {
 			kernel_power_off();
 		} else {
 			WARN(1, "FIXME: NO pm_power_off!!! trying restart\n");
-- 
2.33.1

[PATCH v5 18/21] memory: emif: Use kernel_can_power_off()

[Dmitry Osipenko]

Replace legacy pm_power_off with kernel_can_power_off() helper that
is aware about chained power-off handlers.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/memory/emif.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index 762d0c0f0716..cab10d5274a0 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -630,7 +630,7 @@ static irqreturn_t emif_threaded_isr(int irq, void *dev_id)
 		dev_emerg(emif->dev, "SDRAM temperature exceeds operating limit.. Needs shut down!!!\n");
 
 		/* If we have Power OFF ability, use it, else try restarting */
-		if (pm_power_off) {
+		if (kernel_can_power_off()) {
 			kernel_power_off();
 		} else {
 			WARN(1, "FIXME: NO pm_power_off!!! trying restart\n");
-- 
2.33.1

[PATCH v5 18/21] memory: emif: Use kernel_can_power_off()

[Dmitry Osipenko]

Replace legacy pm_power_off with kernel_can_power_off() helper that
is aware about chained power-off handlers.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/memory/emif.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memory/emif.c b/drivers/memory/emif.c
index 762d0c0f0716..cab10d5274a0 100644
--- a/drivers/memory/emif.c
+++ b/drivers/memory/emif.c
@@ -630,7 +630,7 @@ static irqreturn_t emif_threaded_isr(int irq, void *dev_id)
 		dev_emerg(emif->dev, "SDRAM temperature exceeds operating limit.. Needs shut down!!!\n");
 
 		/* If we have Power OFF ability, use it, else try restarting */
-		if (pm_power_off) {
+		if (kernel_can_power_off()) {
 			kernel_power_off();
 		} else {
 			WARN(1, "FIXME: NO pm_power_off!!! trying restart\n");
-- 
2.33.1

[PATCH v5 19/21] ACPI: power: Switch to sys-off handler API

[Dmitry Osipenko]

Switch to sys-off API that replaces legacy pm_power_off callbacks.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/acpi/sleep.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index eaa47753b758..2e613fddd614 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -47,19 +47,11 @@ static void acpi_sleep_tts_switch(u32 acpi_state)
 	}
 }
 
-static int tts_notify_reboot(struct notifier_block *this,
-			unsigned long code, void *x)
+static void tts_reboot_prepare(struct reboot_prep_data *data)
 {
 	acpi_sleep_tts_switch(ACPI_STATE_S5);
-	return NOTIFY_DONE;
 }
 
-static struct notifier_block tts_notifier = {
-	.notifier_call	= tts_notify_reboot,
-	.next		= NULL,
-	.priority	= 0,
-};
-
 static int acpi_sleep_prepare(u32 acpi_state)
 {
 #ifdef CONFIG_ACPI_SLEEP
@@ -1020,7 +1012,7 @@ static void acpi_sleep_hibernate_setup(void)
 static inline void acpi_sleep_hibernate_setup(void) {}
 #endif /* !CONFIG_HIBERNATION */
 
-static void acpi_power_off_prepare(void)
+static void acpi_power_off_prepare(struct power_off_prep_data *data)
 {
 	/* Prepare to power off the system */
 	acpi_sleep_prepare(ACPI_STATE_S5);
@@ -1028,7 +1020,7 @@ static void acpi_power_off_prepare(void)
 	acpi_os_wait_events_complete();
 }
 
-static void acpi_power_off(void)
+static void acpi_power_off(struct power_off_data *data)
 {
 	/* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
 	pr_debug("%s called\n", __func__);
@@ -1036,6 +1028,11 @@ static void acpi_power_off(void)
 	acpi_enter_sleep_state(ACPI_STATE_S5);
 }
 
+static struct sys_off_handler acpi_sys_off_handler = {
+	.power_off_priority = POWEROFF_PRIO_FIRMWARE,
+	.reboot_prepare_cb = tts_reboot_prepare,
+};
+
 int __init acpi_sleep_init(void)
 {
 	char supported[ACPI_S_STATE_COUNT * 3 + 1];
@@ -1052,8 +1049,8 @@ int __init acpi_sleep_init(void)
 
 	if (acpi_sleep_state_supported(ACPI_STATE_S5)) {
 		sleep_states[ACPI_STATE_S5] = 1;
-		pm_power_off_prepare = acpi_power_off_prepare;
-		pm_power_off = acpi_power_off;
+		acpi_sys_off_handler.power_off_cb = acpi_power_off;
+		acpi_sys_off_handler.power_off_prepare_cb = acpi_power_off_prepare;
 	} else {
 		acpi_no_s5 = true;
 	}
@@ -1069,6 +1066,6 @@ int __init acpi_sleep_init(void)
 	 * Register the tts_notifier to reboot notifier list so that the _TTS
 	 * object can also be evaluated when the system enters S5.
 	 */
-	register_reboot_notifier(&tts_notifier);
+	register_sys_off_handler(&acpi_sys_off_handler);
 	return 0;
 }
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 19/21] ACPI: power: Switch to sys-off handler API

[Dmitry Osipenko]

Switch to sys-off API that replaces legacy pm_power_off callbacks.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/acpi/sleep.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index eaa47753b758..2e613fddd614 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -47,19 +47,11 @@ static void acpi_sleep_tts_switch(u32 acpi_state)
 	}
 }
 
-static int tts_notify_reboot(struct notifier_block *this,
-			unsigned long code, void *x)
+static void tts_reboot_prepare(struct reboot_prep_data *data)
 {
 	acpi_sleep_tts_switch(ACPI_STATE_S5);
-	return NOTIFY_DONE;
 }
 
-static struct notifier_block tts_notifier = {
-	.notifier_call	= tts_notify_reboot,
-	.next		= NULL,
-	.priority	= 0,
-};
-
 static int acpi_sleep_prepare(u32 acpi_state)
 {
 #ifdef CONFIG_ACPI_SLEEP
@@ -1020,7 +1012,7 @@ static void acpi_sleep_hibernate_setup(void)
 static inline void acpi_sleep_hibernate_setup(void) {}
 #endif /* !CONFIG_HIBERNATION */
 
-static void acpi_power_off_prepare(void)
+static void acpi_power_off_prepare(struct power_off_prep_data *data)
 {
 	/* Prepare to power off the system */
 	acpi_sleep_prepare(ACPI_STATE_S5);
@@ -1028,7 +1020,7 @@ static void acpi_power_off_prepare(void)
 	acpi_os_wait_events_complete();
 }
 
-static void acpi_power_off(void)
+static void acpi_power_off(struct power_off_data *data)
 {
 	/* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
 	pr_debug("%s called\n", __func__);
@@ -1036,6 +1028,11 @@ static void acpi_power_off(void)
 	acpi_enter_sleep_state(ACPI_STATE_S5);
 }
 
+static struct sys_off_handler acpi_sys_off_handler = {
+	.power_off_priority = POWEROFF_PRIO_FIRMWARE,
+	.reboot_prepare_cb = tts_reboot_prepare,
+};
+
 int __init acpi_sleep_init(void)
 {
 	char supported[ACPI_S_STATE_COUNT * 3 + 1];
@@ -1052,8 +1049,8 @@ int __init acpi_sleep_init(void)
 
 	if (acpi_sleep_state_supported(ACPI_STATE_S5)) {
 		sleep_states[ACPI_STATE_S5] = 1;
-		pm_power_off_prepare = acpi_power_off_prepare;
-		pm_power_off = acpi_power_off;
+		acpi_sys_off_handler.power_off_cb = acpi_power_off;
+		acpi_sys_off_handler.power_off_prepare_cb = acpi_power_off_prepare;
 	} else {
 		acpi_no_s5 = true;
 	}
@@ -1069,6 +1066,6 @@ int __init acpi_sleep_init(void)
 	 * Register the tts_notifier to reboot notifier list so that the _TTS
 	 * object can also be evaluated when the system enters S5.
 	 */
-	register_reboot_notifier(&tts_notifier);
+	register_sys_off_handler(&acpi_sys_off_handler);
 	return 0;
 }
-- 
2.33.1

[PATCH v5 19/21] ACPI: power: Switch to sys-off handler API

[Dmitry Osipenko]

Switch to sys-off API that replaces legacy pm_power_off callbacks.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/acpi/sleep.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index eaa47753b758..2e613fddd614 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -47,19 +47,11 @@ static void acpi_sleep_tts_switch(u32 acpi_state)
 	}
 }
 
-static int tts_notify_reboot(struct notifier_block *this,
-			unsigned long code, void *x)
+static void tts_reboot_prepare(struct reboot_prep_data *data)
 {
 	acpi_sleep_tts_switch(ACPI_STATE_S5);
-	return NOTIFY_DONE;
 }
 
-static struct notifier_block tts_notifier = {
-	.notifier_call	= tts_notify_reboot,
-	.next		= NULL,
-	.priority	= 0,
-};
-
 static int acpi_sleep_prepare(u32 acpi_state)
 {
 #ifdef CONFIG_ACPI_SLEEP
@@ -1020,7 +1012,7 @@ static void acpi_sleep_hibernate_setup(void)
 static inline void acpi_sleep_hibernate_setup(void) {}
 #endif /* !CONFIG_HIBERNATION */
 
-static void acpi_power_off_prepare(void)
+static void acpi_power_off_prepare(struct power_off_prep_data *data)
 {
 	/* Prepare to power off the system */
 	acpi_sleep_prepare(ACPI_STATE_S5);
@@ -1028,7 +1020,7 @@ static void acpi_power_off_prepare(void)
 	acpi_os_wait_events_complete();
 }
 
-static void acpi_power_off(void)
+static void acpi_power_off(struct power_off_data *data)
 {
 	/* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
 	pr_debug("%s called\n", __func__);
@@ -1036,6 +1028,11 @@ static void acpi_power_off(void)
 	acpi_enter_sleep_state(ACPI_STATE_S5);
 }
 
+static struct sys_off_handler acpi_sys_off_handler = {
+	.power_off_priority = POWEROFF_PRIO_FIRMWARE,
+	.reboot_prepare_cb = tts_reboot_prepare,
+};
+
 int __init acpi_sleep_init(void)
 {
 	char supported[ACPI_S_STATE_COUNT * 3 + 1];
@@ -1052,8 +1049,8 @@ int __init acpi_sleep_init(void)
 
 	if (acpi_sleep_state_supported(ACPI_STATE_S5)) {
 		sleep_states[ACPI_STATE_S5] = 1;
-		pm_power_off_prepare = acpi_power_off_prepare;
-		pm_power_off = acpi_power_off;
+		acpi_sys_off_handler.power_off_cb = acpi_power_off;
+		acpi_sys_off_handler.power_off_prepare_cb = acpi_power_off_prepare;
 	} else {
 		acpi_no_s5 = true;
 	}
@@ -1069,6 +1066,6 @@ int __init acpi_sleep_init(void)
 	 * Register the tts_notifier to reboot notifier list so that the _TTS
 	 * object can also be evaluated when the system enters S5.
 	 */
-	register_reboot_notifier(&tts_notifier);
+	register_sys_off_handler(&acpi_sys_off_handler);
 	return 0;
 }
-- 
2.33.1

[PATCH v5 19/21] ACPI: power: Switch to sys-off handler API

[Dmitry Osipenko]

Switch to sys-off API that replaces legacy pm_power_off callbacks.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/acpi/sleep.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index eaa47753b758..2e613fddd614 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -47,19 +47,11 @@ static void acpi_sleep_tts_switch(u32 acpi_state)
 	}
 }
 
-static int tts_notify_reboot(struct notifier_block *this,
-			unsigned long code, void *x)
+static void tts_reboot_prepare(struct reboot_prep_data *data)
 {
 	acpi_sleep_tts_switch(ACPI_STATE_S5);
-	return NOTIFY_DONE;
 }
 
-static struct notifier_block tts_notifier = {
-	.notifier_call	= tts_notify_reboot,
-	.next		= NULL,
-	.priority	= 0,
-};
-
 static int acpi_sleep_prepare(u32 acpi_state)
 {
 #ifdef CONFIG_ACPI_SLEEP
@@ -1020,7 +1012,7 @@ static void acpi_sleep_hibernate_setup(void)
 static inline void acpi_sleep_hibernate_setup(void) {}
 #endif /* !CONFIG_HIBERNATION */
 
-static void acpi_power_off_prepare(void)
+static void acpi_power_off_prepare(struct power_off_prep_data *data)
 {
 	/* Prepare to power off the system */
 	acpi_sleep_prepare(ACPI_STATE_S5);
@@ -1028,7 +1020,7 @@ static void acpi_power_off_prepare(void)
 	acpi_os_wait_events_complete();
 }
 
-static void acpi_power_off(void)
+static void acpi_power_off(struct power_off_data *data)
 {
 	/* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
 	pr_debug("%s called\n", __func__);
@@ -1036,6 +1028,11 @@ static void acpi_power_off(void)
 	acpi_enter_sleep_state(ACPI_STATE_S5);
 }
 
+static struct sys_off_handler acpi_sys_off_handler = {
+	.power_off_priority = POWEROFF_PRIO_FIRMWARE,
+	.reboot_prepare_cb = tts_reboot_prepare,
+};
+
 int __init acpi_sleep_init(void)
 {
 	char supported[ACPI_S_STATE_COUNT * 3 + 1];
@@ -1052,8 +1049,8 @@ int __init acpi_sleep_init(void)
 
 	if (acpi_sleep_state_supported(ACPI_STATE_S5)) {
 		sleep_states[ACPI_STATE_S5] = 1;
-		pm_power_off_prepare = acpi_power_off_prepare;
-		pm_power_off = acpi_power_off;
+		acpi_sys_off_handler.power_off_cb = acpi_power_off;
+		acpi_sys_off_handler.power_off_prepare_cb = acpi_power_off_prepare;
 	} else {
 		acpi_no_s5 = true;
 	}
@@ -1069,6 +1066,6 @@ int __init acpi_sleep_init(void)
 	 * Register the tts_notifier to reboot notifier list so that the _TTS
 	 * object can also be evaluated when the system enters S5.
 	 */
-	register_reboot_notifier(&tts_notifier);
+	register_sys_off_handler(&acpi_sys_off_handler);
 	return 0;
 }
-- 
2.33.1

[PATCH v5 20/21] regulator: pfuze100: Use devm_register_sys_off_handler()

[Dmitry Osipenko]

Use devm_register_sys_off_handler() that replaces global
pm_power_off_prepare variable and allows to register multiple
power-off handlers.

Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/regulator/pfuze100-regulator.c | 38 ++++++++++----------------
 1 file changed, 14 insertions(+), 24 deletions(-)

diff --git a/drivers/regulator/pfuze100-regulator.c b/drivers/regulator/pfuze100-regulator.c
index d60d7d1b7fa2..2eca8d43a097 100644
--- a/drivers/regulator/pfuze100-regulator.c
+++ b/drivers/regulator/pfuze100-regulator.c
@@ -10,6 +10,7 @@
 #include <linux/of_device.h>
 #include <linux/regulator/of_regulator.h>
 #include <linux/platform_device.h>
+#include <linux/reboot.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/pfuze100.h>
@@ -76,6 +77,7 @@ struct pfuze_chip {
 	struct pfuze_regulator regulator_descs[PFUZE100_MAX_REGULATOR];
 	struct regulator_dev *regulators[PFUZE100_MAX_REGULATOR];
 	struct pfuze_regulator *pfuze_regulators;
+	struct sys_off_handler sys_off;
 };
 
 static const int pfuze100_swbst[] = {
@@ -569,10 +571,10 @@ static inline struct device_node *match_of_node(int index)
 	return pfuze_matches[index].of_node;
 }
 
-static struct pfuze_chip *syspm_pfuze_chip;
-
-static void pfuze_power_off_prepare(void)
+static void pfuze_power_off_prepare(struct power_off_prep_data *data)
 {
+	struct pfuze_chip *syspm_pfuze_chip = data->cb_data;
+
 	dev_info(syspm_pfuze_chip->dev, "Configure standby mode for power off");
 
 	/* Switch from default mode: APS/APS to APS/Off */
@@ -611,24 +613,23 @@ static void pfuze_power_off_prepare(void)
 
 static int pfuze_power_off_prepare_init(struct pfuze_chip *pfuze_chip)
 {
+	int err;
+
 	if (pfuze_chip->chip_id != PFUZE100) {
 		dev_warn(pfuze_chip->dev, "Requested pm_power_off_prepare handler for not supported chip\n");
 		return -ENODEV;
 	}
 
-	if (pm_power_off_prepare) {
-		dev_warn(pfuze_chip->dev, "pm_power_off_prepare is already registered.\n");
-		return -EBUSY;
-	}
+	pfuze_chip->sys_off.power_off_prepare_cb = pfuze_power_off_prepare;
+	pfuze_chip->sys_off.cb_data = pfuze_chip;
 
-	if (syspm_pfuze_chip) {
-		dev_warn(pfuze_chip->dev, "syspm_pfuze_chip is already set.\n");
-		return -EBUSY;
+	err = devm_register_sys_off_handler(pfuze_chip->dev, &pfuze_chip->sys_off);
+	if (err) {
+		dev_err(pfuze_chip->dev,
+			"failed to register sys-off handler: %d\n", err);
+		return err;
 	}
 
-	syspm_pfuze_chip = pfuze_chip;
-	pm_power_off_prepare = pfuze_power_off_prepare;
-
 	return 0;
 }
 
@@ -837,23 +838,12 @@ static int pfuze100_regulator_probe(struct i2c_client *client,
 	return 0;
 }
 
-static int pfuze100_regulator_remove(struct i2c_client *client)
-{
-	if (syspm_pfuze_chip) {
-		syspm_pfuze_chip = NULL;
-		pm_power_off_prepare = NULL;
-	}
-
-	return 0;
-}
-
 static struct i2c_driver pfuze_driver = {
 	.driver = {
 		.name = "pfuze100-regulator",
 		.of_match_table = pfuze_dt_ids,
 	},
 	.probe = pfuze100_regulator_probe,
-	.remove = pfuze100_regulator_remove,
 };
 module_i2c_driver(pfuze_driver);
 
-- 
2.33.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 20/21] regulator: pfuze100: Use devm_register_sys_off_handler()

[Dmitry Osipenko]

Use devm_register_sys_off_handler() that replaces global
pm_power_off_prepare variable and allows to register multiple
power-off handlers.

Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/regulator/pfuze100-regulator.c | 38 ++++++++++----------------
 1 file changed, 14 insertions(+), 24 deletions(-)

diff --git a/drivers/regulator/pfuze100-regulator.c b/drivers/regulator/pfuze100-regulator.c
index d60d7d1b7fa2..2eca8d43a097 100644
--- a/drivers/regulator/pfuze100-regulator.c
+++ b/drivers/regulator/pfuze100-regulator.c
@@ -10,6 +10,7 @@
 #include <linux/of_device.h>
 #include <linux/regulator/of_regulator.h>
 #include <linux/platform_device.h>
+#include <linux/reboot.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/pfuze100.h>
@@ -76,6 +77,7 @@ struct pfuze_chip {
 	struct pfuze_regulator regulator_descs[PFUZE100_MAX_REGULATOR];
 	struct regulator_dev *regulators[PFUZE100_MAX_REGULATOR];
 	struct pfuze_regulator *pfuze_regulators;
+	struct sys_off_handler sys_off;
 };
 
 static const int pfuze100_swbst[] = {
@@ -569,10 +571,10 @@ static inline struct device_node *match_of_node(int index)
 	return pfuze_matches[index].of_node;
 }
 
-static struct pfuze_chip *syspm_pfuze_chip;
-
-static void pfuze_power_off_prepare(void)
+static void pfuze_power_off_prepare(struct power_off_prep_data *data)
 {
+	struct pfuze_chip *syspm_pfuze_chip = data->cb_data;
+
 	dev_info(syspm_pfuze_chip->dev, "Configure standby mode for power off");
 
 	/* Switch from default mode: APS/APS to APS/Off */
@@ -611,24 +613,23 @@ static void pfuze_power_off_prepare(void)
 
 static int pfuze_power_off_prepare_init(struct pfuze_chip *pfuze_chip)
 {
+	int err;
+
 	if (pfuze_chip->chip_id != PFUZE100) {
 		dev_warn(pfuze_chip->dev, "Requested pm_power_off_prepare handler for not supported chip\n");
 		return -ENODEV;
 	}
 
-	if (pm_power_off_prepare) {
-		dev_warn(pfuze_chip->dev, "pm_power_off_prepare is already registered.\n");
-		return -EBUSY;
-	}
+	pfuze_chip->sys_off.power_off_prepare_cb = pfuze_power_off_prepare;
+	pfuze_chip->sys_off.cb_data = pfuze_chip;
 
-	if (syspm_pfuze_chip) {
-		dev_warn(pfuze_chip->dev, "syspm_pfuze_chip is already set.\n");
-		return -EBUSY;
+	err = devm_register_sys_off_handler(pfuze_chip->dev, &pfuze_chip->sys_off);
+	if (err) {
+		dev_err(pfuze_chip->dev,
+			"failed to register sys-off handler: %d\n", err);
+		return err;
 	}
 
-	syspm_pfuze_chip = pfuze_chip;
-	pm_power_off_prepare = pfuze_power_off_prepare;
-
 	return 0;
 }
 
@@ -837,23 +838,12 @@ static int pfuze100_regulator_probe(struct i2c_client *client,
 	return 0;
 }
 
-static int pfuze100_regulator_remove(struct i2c_client *client)
-{
-	if (syspm_pfuze_chip) {
-		syspm_pfuze_chip = NULL;
-		pm_power_off_prepare = NULL;
-	}
-
-	return 0;
-}
-
 static struct i2c_driver pfuze_driver = {
 	.driver = {
 		.name = "pfuze100-regulator",
 		.of_match_table = pfuze_dt_ids,
 	},
 	.probe = pfuze100_regulator_probe,
-	.remove = pfuze100_regulator_remove,
 };
 module_i2c_driver(pfuze_driver);
 
-- 
2.33.1

[PATCH v5 20/21] regulator: pfuze100: Use devm_register_sys_off_handler()

[Dmitry Osipenko]

Use devm_register_sys_off_handler() that replaces global
pm_power_off_prepare variable and allows to register multiple
power-off handlers.

Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/regulator/pfuze100-regulator.c | 38 ++++++++++----------------
 1 file changed, 14 insertions(+), 24 deletions(-)

diff --git a/drivers/regulator/pfuze100-regulator.c b/drivers/regulator/pfuze100-regulator.c
index d60d7d1b7fa2..2eca8d43a097 100644
--- a/drivers/regulator/pfuze100-regulator.c
+++ b/drivers/regulator/pfuze100-regulator.c
@@ -10,6 +10,7 @@
 #include <linux/of_device.h>
 #include <linux/regulator/of_regulator.h>
 #include <linux/platform_device.h>
+#include <linux/reboot.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/pfuze100.h>
@@ -76,6 +77,7 @@ struct pfuze_chip {
 	struct pfuze_regulator regulator_descs[PFUZE100_MAX_REGULATOR];
 	struct regulator_dev *regulators[PFUZE100_MAX_REGULATOR];
 	struct pfuze_regulator *pfuze_regulators;
+	struct sys_off_handler sys_off;
 };
 
 static const int pfuze100_swbst[] = {
@@ -569,10 +571,10 @@ static inline struct device_node *match_of_node(int index)
 	return pfuze_matches[index].of_node;
 }
 
-static struct pfuze_chip *syspm_pfuze_chip;
-
-static void pfuze_power_off_prepare(void)
+static void pfuze_power_off_prepare(struct power_off_prep_data *data)
 {
+	struct pfuze_chip *syspm_pfuze_chip = data->cb_data;
+
 	dev_info(syspm_pfuze_chip->dev, "Configure standby mode for power off");
 
 	/* Switch from default mode: APS/APS to APS/Off */
@@ -611,24 +613,23 @@ static void pfuze_power_off_prepare(void)
 
 static int pfuze_power_off_prepare_init(struct pfuze_chip *pfuze_chip)
 {
+	int err;
+
 	if (pfuze_chip->chip_id != PFUZE100) {
 		dev_warn(pfuze_chip->dev, "Requested pm_power_off_prepare handler for not supported chip\n");
 		return -ENODEV;
 	}
 
-	if (pm_power_off_prepare) {
-		dev_warn(pfuze_chip->dev, "pm_power_off_prepare is already registered.\n");
-		return -EBUSY;
-	}
+	pfuze_chip->sys_off.power_off_prepare_cb = pfuze_power_off_prepare;
+	pfuze_chip->sys_off.cb_data = pfuze_chip;
 
-	if (syspm_pfuze_chip) {
-		dev_warn(pfuze_chip->dev, "syspm_pfuze_chip is already set.\n");
-		return -EBUSY;
+	err = devm_register_sys_off_handler(pfuze_chip->dev, &pfuze_chip->sys_off);
+	if (err) {
+		dev_err(pfuze_chip->dev,
+			"failed to register sys-off handler: %d\n", err);
+		return err;
 	}
 
-	syspm_pfuze_chip = pfuze_chip;
-	pm_power_off_prepare = pfuze_power_off_prepare;
-
 	return 0;
 }
 
@@ -837,23 +838,12 @@ static int pfuze100_regulator_probe(struct i2c_client *client,
 	return 0;
 }
 
-static int pfuze100_regulator_remove(struct i2c_client *client)
-{
-	if (syspm_pfuze_chip) {
-		syspm_pfuze_chip = NULL;
-		pm_power_off_prepare = NULL;
-	}
-
-	return 0;
-}
-
 static struct i2c_driver pfuze_driver = {
 	.driver = {
 		.name = "pfuze100-regulator",
 		.of_match_table = pfuze_dt_ids,
 	},
 	.probe = pfuze100_regulator_probe,
-	.remove = pfuze100_regulator_remove,
 };
 module_i2c_driver(pfuze_driver);
 
-- 
2.33.1

[PATCH v5 20/21] regulator: pfuze100: Use devm_register_sys_off_handler()

[Dmitry Osipenko]

Use devm_register_sys_off_handler() that replaces global
pm_power_off_prepare variable and allows to register multiple
power-off handlers.

Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/regulator/pfuze100-regulator.c | 38 ++++++++++----------------
 1 file changed, 14 insertions(+), 24 deletions(-)

diff --git a/drivers/regulator/pfuze100-regulator.c b/drivers/regulator/pfuze100-regulator.c
index d60d7d1b7fa2..2eca8d43a097 100644
--- a/drivers/regulator/pfuze100-regulator.c
+++ b/drivers/regulator/pfuze100-regulator.c
@@ -10,6 +10,7 @@
 #include <linux/of_device.h>
 #include <linux/regulator/of_regulator.h>
 #include <linux/platform_device.h>
+#include <linux/reboot.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/pfuze100.h>
@@ -76,6 +77,7 @@ struct pfuze_chip {
 	struct pfuze_regulator regulator_descs[PFUZE100_MAX_REGULATOR];
 	struct regulator_dev *regulators[PFUZE100_MAX_REGULATOR];
 	struct pfuze_regulator *pfuze_regulators;
+	struct sys_off_handler sys_off;
 };
 
 static const int pfuze100_swbst[] = {
@@ -569,10 +571,10 @@ static inline struct device_node *match_of_node(int index)
 	return pfuze_matches[index].of_node;
 }
 
-static struct pfuze_chip *syspm_pfuze_chip;
-
-static void pfuze_power_off_prepare(void)
+static void pfuze_power_off_prepare(struct power_off_prep_data *data)
 {
+	struct pfuze_chip *syspm_pfuze_chip = data->cb_data;
+
 	dev_info(syspm_pfuze_chip->dev, "Configure standby mode for power off");
 
 	/* Switch from default mode: APS/APS to APS/Off */
@@ -611,24 +613,23 @@ static void pfuze_power_off_prepare(void)
 
 static int pfuze_power_off_prepare_init(struct pfuze_chip *pfuze_chip)
 {
+	int err;
+
 	if (pfuze_chip->chip_id != PFUZE100) {
 		dev_warn(pfuze_chip->dev, "Requested pm_power_off_prepare handler for not supported chip\n");
 		return -ENODEV;
 	}
 
-	if (pm_power_off_prepare) {
-		dev_warn(pfuze_chip->dev, "pm_power_off_prepare is already registered.\n");
-		return -EBUSY;
-	}
+	pfuze_chip->sys_off.power_off_prepare_cb = pfuze_power_off_prepare;
+	pfuze_chip->sys_off.cb_data = pfuze_chip;
 
-	if (syspm_pfuze_chip) {
-		dev_warn(pfuze_chip->dev, "syspm_pfuze_chip is already set.\n");
-		return -EBUSY;
+	err = devm_register_sys_off_handler(pfuze_chip->dev, &pfuze_chip->sys_off);
+	if (err) {
+		dev_err(pfuze_chip->dev,
+			"failed to register sys-off handler: %d\n", err);
+		return err;
 	}
 
-	syspm_pfuze_chip = pfuze_chip;
-	pm_power_off_prepare = pfuze_power_off_prepare;
-
 	return 0;
 }
 
@@ -837,23 +838,12 @@ static int pfuze100_regulator_probe(struct i2c_client *client,
 	return 0;
 }
 
-static int pfuze100_regulator_remove(struct i2c_client *client)
-{
-	if (syspm_pfuze_chip) {
-		syspm_pfuze_chip = NULL;
-		pm_power_off_prepare = NULL;
-	}
-
-	return 0;
-}
-
 static struct i2c_driver pfuze_driver = {
 	.driver = {
 		.name = "pfuze100-regulator",
 		.of_match_table = pfuze_dt_ids,
 	},
 	.probe = pfuze100_regulator_probe,
-	.remove = pfuze100_regulator_remove,
 };
 module_i2c_driver(pfuze_driver);
 
-- 
2.33.1

[PATCH v5 21/21] reboot: Remove pm_power_off_prepare()

[Dmitry Osipenko]

All pm_power_off_prepare() users were converted to sys-off handler API.
Remove the obsolete callback.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/pm.h |  1 -
 kernel/reboot.c    | 11 -----------
 2 files changed, 12 deletions(-)

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 1d8209c09686..d9bf1426f81e 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -20,7 +20,6 @@
  * Callbacks for platform drivers to implement.
  */
 extern void (*pm_power_off)(void);
-extern void (*pm_power_off_prepare)(void);
 
 struct device; /* we have a circular dep with device.h */
 #ifdef CONFIG_VT_CONSOLE_SLEEP
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 3085873a876f..2f79d4f7cfaa 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -48,13 +48,6 @@ int reboot_cpu;
 enum reboot_type reboot_type = BOOT_ACPI;
 int reboot_force;
 
-/*
- * If set, this is used for preparing the system to power off.
- */
-
-void (*pm_power_off_prepare)(void);
-EXPORT_SYMBOL_GPL(pm_power_off_prepare);
-
 /**
  *	emergency_restart - reboot the system
  *
@@ -829,10 +822,6 @@ void do_kernel_power_off(void)
 
 static void do_kernel_power_off_prepare(void)
 {
-	/* legacy pm_power_off_prepare() is unchained and has highest priority */
-	if (pm_power_off_prepare)
-		return pm_power_off_prepare();
-
 	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_PREPARE,
 				     NULL);
 }
-- 
2.33.1


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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v5 21/21] reboot: Remove pm_power_off_prepare()

[Dmitry Osipenko]

All pm_power_off_prepare() users were converted to sys-off handler API.
Remove the obsolete callback.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/pm.h |  1 -
 kernel/reboot.c    | 11 -----------
 2 files changed, 12 deletions(-)

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 1d8209c09686..d9bf1426f81e 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -20,7 +20,6 @@
  * Callbacks for platform drivers to implement.
  */
 extern void (*pm_power_off)(void);
-extern void (*pm_power_off_prepare)(void);
 
 struct device; /* we have a circular dep with device.h */
 #ifdef CONFIG_VT_CONSOLE_SLEEP
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 3085873a876f..2f79d4f7cfaa 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -48,13 +48,6 @@ int reboot_cpu;
 enum reboot_type reboot_type = BOOT_ACPI;
 int reboot_force;
 
-/*
- * If set, this is used for preparing the system to power off.
- */
-
-void (*pm_power_off_prepare)(void);
-EXPORT_SYMBOL_GPL(pm_power_off_prepare);
-
 /**
  *	emergency_restart - reboot the system
  *
@@ -829,10 +822,6 @@ void do_kernel_power_off(void)
 
 static void do_kernel_power_off_prepare(void)
 {
-	/* legacy pm_power_off_prepare() is unchained and has highest priority */
-	if (pm_power_off_prepare)
-		return pm_power_off_prepare();
-
 	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_PREPARE,
 				     NULL);
 }
-- 
2.33.1

[PATCH v5 21/21] reboot: Remove pm_power_off_prepare()

[Dmitry Osipenko]

All pm_power_off_prepare() users were converted to sys-off handler API.
Remove the obsolete callback.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/pm.h |  1 -
 kernel/reboot.c    | 11 -----------
 2 files changed, 12 deletions(-)

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 1d8209c09686..d9bf1426f81e 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -20,7 +20,6 @@
  * Callbacks for platform drivers to implement.
  */
 extern void (*pm_power_off)(void);
-extern void (*pm_power_off_prepare)(void);
 
 struct device; /* we have a circular dep with device.h */
 #ifdef CONFIG_VT_CONSOLE_SLEEP
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 3085873a876f..2f79d4f7cfaa 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -48,13 +48,6 @@ int reboot_cpu;
 enum reboot_type reboot_type = BOOT_ACPI;
 int reboot_force;
 
-/*
- * If set, this is used for preparing the system to power off.
- */
-
-void (*pm_power_off_prepare)(void);
-EXPORT_SYMBOL_GPL(pm_power_off_prepare);
-
 /**
  *	emergency_restart - reboot the system
  *
@@ -829,10 +822,6 @@ void do_kernel_power_off(void)
 
 static void do_kernel_power_off_prepare(void)
 {
-	/* legacy pm_power_off_prepare() is unchained and has highest priority */
-	if (pm_power_off_prepare)
-		return pm_power_off_prepare();
-
 	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_PREPARE,
 				     NULL);
 }
-- 
2.33.1

[PATCH v5 21/21] reboot: Remove pm_power_off_prepare()

[Dmitry Osipenko]

All pm_power_off_prepare() users were converted to sys-off handler API.
Remove the obsolete callback.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 include/linux/pm.h |  1 -
 kernel/reboot.c    | 11 -----------
 2 files changed, 12 deletions(-)

diff --git a/include/linux/pm.h b/include/linux/pm.h
index 1d8209c09686..d9bf1426f81e 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -20,7 +20,6 @@
  * Callbacks for platform drivers to implement.
  */
 extern void (*pm_power_off)(void);
-extern void (*pm_power_off_prepare)(void);
 
 struct device; /* we have a circular dep with device.h */
 #ifdef CONFIG_VT_CONSOLE_SLEEP
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 3085873a876f..2f79d4f7cfaa 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -48,13 +48,6 @@ int reboot_cpu;
 enum reboot_type reboot_type = BOOT_ACPI;
 int reboot_force;
 
-/*
- * If set, this is used for preparing the system to power off.
- */
-
-void (*pm_power_off_prepare)(void);
-EXPORT_SYMBOL_GPL(pm_power_off_prepare);
-
 /**
  *	emergency_restart - reboot the system
  *
@@ -829,10 +822,6 @@ void do_kernel_power_off(void)
 
 static void do_kernel_power_off_prepare(void)
 {
-	/* legacy pm_power_off_prepare() is unchained and has highest priority */
-	if (pm_power_off_prepare)
-		return pm_power_off_prepare();
-
 	blocking_notifier_call_chain(&power_off_handler_list, POWEROFF_PREPARE,
 				     NULL);
 }
-- 
2.33.1

Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Michał Mirosław]

On Mon, Dec 13, 2021 at 12:02:52AM +0300, Dmitry Osipenko wrote:
[...]
> +/**
> + * struct power_off_data - Power-off callback argument
> + *
> + * @cb_data: Callback data.
> + */
> +struct power_off_data {
> +	void *cb_data;
> +};
> +
> +/**
> + * struct power_off_prep_data - Power-off preparation callback argument
> + *
> + * @cb_data: Callback data.
> + */
> +struct power_off_prep_data {
> +	void *cb_data;
> +};

Why two exactly same structures? Why only a single pointer instead? If
it just to enable type-checking callbacks, then thouse could be opaque
or zero-sized structs that would be embedded or casted away in
respective callbacks.

> +
> +/**
> + * struct restart_data - Restart callback argument
> + *
> + * @cb_data: Callback data.
> + * @cmd: Restart command string.
> + * @stop_chain: Further lower priority callbacks won't be executed if set to
> + *		true. Can be changed within callback. Default is false.
> + * @mode: Reboot mode ID.
> + */
> +struct restart_data {
> +	void *cb_data;
> +	const char *cmd;
> +	bool stop_chain;
> +	enum reboot_mode mode;
> +};
> +
> +/**
> + * struct reboot_prep_data - Reboot and shutdown preparation callback argument
> + *
> + * @cb_data: Callback data.
> + * @cmd: Restart command string.
> + * @stop_chain: Further lower priority callbacks won't be executed if set to
> + *		true. Can be changed within callback. Default is false.

Why would we want to stop power-off or erboot chain? If the callback
succeded, then further calls won't be made. If it doesn't succeed, but
possibly breaks the system somehow, it shouldn't return. Then the only
case left would be to just try the next method of shutting down.

> + * @mode: Preparation mode ID.
> + */
> +struct reboot_prep_data {
> +	void *cb_data;
> +	const char *cmd;
> +	bool stop_chain;
> +	enum reboot_prepare_mode mode;
> +};
> +
> +struct sys_off_handler_private_data {
> +	struct notifier_block power_off_nb;
> +	struct notifier_block restart_nb;
> +	struct notifier_block reboot_nb;

What's the difference between restart and reboot?

> +	void (*platform_power_off_cb)(void);
> +	void (*simple_power_off_cb)(void *data);
> +	void *simple_power_off_cb_data;
> +	bool registered;
> +};

BTW, I couldn't find a right description of my idea of unifying the
chains before, so let me sketch it now.

The idea is to have a single system-off chain in which the callback
gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
would be called, and if at least one returned true, then the shutdown
mode would continue. All of PREP_* would be called then. After that
all DO_* would be tried until one doesn't return (succeeded or broke
the system hard). Classic for(;;); could be a final fallback for the
case where arch/machine (lowest priority) call would return instead
of halting the system in machine-dependent way. The QUERY and PREP
stages could be combined, but I haven't thought about it enough to
see what conditions would need to be imposed on the callbacks in
that case (maybe it's not worth the trouble, since it isn't a fast
path anyway?). The goal here is to have less (duplicated) code in
kernel, but otherwise it seems equivalent to your API proposal.

Best Regards
Michał Mirosław

Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Michał Mirosław]

On Mon, Dec 13, 2021 at 12:02:52AM +0300, Dmitry Osipenko wrote:
[...]
> +/**
> + * struct power_off_data - Power-off callback argument
> + *
> + * @cb_data: Callback data.
> + */
> +struct power_off_data {
> +	void *cb_data;
> +};
> +
> +/**
> + * struct power_off_prep_data - Power-off preparation callback argument
> + *
> + * @cb_data: Callback data.
> + */
> +struct power_off_prep_data {
> +	void *cb_data;
> +};

Why two exactly same structures? Why only a single pointer instead? If
it just to enable type-checking callbacks, then thouse could be opaque
or zero-sized structs that would be embedded or casted away in
respective callbacks.

> +
> +/**
> + * struct restart_data - Restart callback argument
> + *
> + * @cb_data: Callback data.
> + * @cmd: Restart command string.
> + * @stop_chain: Further lower priority callbacks won't be executed if set to
> + *		true. Can be changed within callback. Default is false.
> + * @mode: Reboot mode ID.
> + */
> +struct restart_data {
> +	void *cb_data;
> +	const char *cmd;
> +	bool stop_chain;
> +	enum reboot_mode mode;
> +};
> +
> +/**
> + * struct reboot_prep_data - Reboot and shutdown preparation callback argument
> + *
> + * @cb_data: Callback data.
> + * @cmd: Restart command string.
> + * @stop_chain: Further lower priority callbacks won't be executed if set to
> + *		true. Can be changed within callback. Default is false.

Why would we want to stop power-off or erboot chain? If the callback
succeded, then further calls won't be made. If it doesn't succeed, but
possibly breaks the system somehow, it shouldn't return. Then the only
case left would be to just try the next method of shutting down.

> + * @mode: Preparation mode ID.
> + */
> +struct reboot_prep_data {
> +	void *cb_data;
> +	const char *cmd;
> +	bool stop_chain;
> +	enum reboot_prepare_mode mode;
> +};
> +
> +struct sys_off_handler_private_data {
> +	struct notifier_block power_off_nb;
> +	struct notifier_block restart_nb;
> +	struct notifier_block reboot_nb;

What's the difference between restart and reboot?

> +	void (*platform_power_off_cb)(void);
> +	void (*simple_power_off_cb)(void *data);
> +	void *simple_power_off_cb_data;
> +	bool registered;
> +};

BTW, I couldn't find a right description of my idea of unifying the
chains before, so let me sketch it now.

The idea is to have a single system-off chain in which the callback
gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
would be called, and if at least one returned true, then the shutdown
mode would continue. All of PREP_* would be called then. After that
all DO_* would be tried until one doesn't return (succeeded or broke
the system hard). Classic for(;;); could be a final fallback for the
case where arch/machine (lowest priority) call would return instead
of halting the system in machine-dependent way. The QUERY and PREP
stages could be combined, but I haven't thought about it enough to
see what conditions would need to be imposed on the callbacks in
that case (maybe it's not worth the trouble, since it isn't a fast
path anyway?). The goal here is to have less (duplicated) code in
kernel, but otherwise it seems equivalent to your API proposal.

Best Regards
Michał Mirosław

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linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Michał Mirosław]

On Mon, Dec 13, 2021 at 12:02:52AM +0300, Dmitry Osipenko wrote:
[...]
> +/**
> + * struct power_off_data - Power-off callback argument
> + *
> + * @cb_data: Callback data.
> + */
> +struct power_off_data {
> +	void *cb_data;
> +};
> +
> +/**
> + * struct power_off_prep_data - Power-off preparation callback argument
> + *
> + * @cb_data: Callback data.
> + */
> +struct power_off_prep_data {
> +	void *cb_data;
> +};

Why two exactly same structures? Why only a single pointer instead? If
it just to enable type-checking callbacks, then thouse could be opaque
or zero-sized structs that would be embedded or casted away in
respective callbacks.

> +
> +/**
> + * struct restart_data - Restart callback argument
> + *
> + * @cb_data: Callback data.
> + * @cmd: Restart command string.
> + * @stop_chain: Further lower priority callbacks won't be executed if set to
> + *		true. Can be changed within callback. Default is false.
> + * @mode: Reboot mode ID.
> + */
> +struct restart_data {
> +	void *cb_data;
> +	const char *cmd;
> +	bool stop_chain;
> +	enum reboot_mode mode;
> +};
> +
> +/**
> + * struct reboot_prep_data - Reboot and shutdown preparation callback argument
> + *
> + * @cb_data: Callback data.
> + * @cmd: Restart command string.
> + * @stop_chain: Further lower priority callbacks won't be executed if set to
> + *		true. Can be changed within callback. Default is false.

Why would we want to stop power-off or erboot chain? If the callback
succeded, then further calls won't be made. If it doesn't succeed, but
possibly breaks the system somehow, it shouldn't return. Then the only
case left would be to just try the next method of shutting down.

> + * @mode: Preparation mode ID.
> + */
> +struct reboot_prep_data {
> +	void *cb_data;
> +	const char *cmd;
> +	bool stop_chain;
> +	enum reboot_prepare_mode mode;
> +};
> +
> +struct sys_off_handler_private_data {
> +	struct notifier_block power_off_nb;
> +	struct notifier_block restart_nb;
> +	struct notifier_block reboot_nb;

What's the difference between restart and reboot?

> +	void (*platform_power_off_cb)(void);
> +	void (*simple_power_off_cb)(void *data);
> +	void *simple_power_off_cb_data;
> +	bool registered;
> +};

BTW, I couldn't find a right description of my idea of unifying the
chains before, so let me sketch it now.

The idea is to have a single system-off chain in which the callback
gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
would be called, and if at least one returned true, then the shutdown
mode would continue. All of PREP_* would be called then. After that
all DO_* would be tried until one doesn't return (succeeded or broke
the system hard). Classic for(;;); could be a final fallback for the
case where arch/machine (lowest priority) call would return instead
of halting the system in machine-dependent way. The QUERY and PREP
stages could be combined, but I haven't thought about it enough to
see what conditions would need to be imposed on the callbacks in
that case (maybe it's not worth the trouble, since it isn't a fast
path anyway?). The goal here is to have less (duplicated) code in
kernel, but otherwise it seems equivalent to your API proposal.

Best Regards
Michał Mirosław

Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Michał Mirosław]

On Mon, Dec 13, 2021 at 12:02:52AM +0300, Dmitry Osipenko wrote:
[...]
> +/**
> + * struct power_off_data - Power-off callback argument
> + *
> + * @cb_data: Callback data.
> + */
> +struct power_off_data {
> +	void *cb_data;
> +};
> +
> +/**
> + * struct power_off_prep_data - Power-off preparation callback argument
> + *
> + * @cb_data: Callback data.
> + */
> +struct power_off_prep_data {
> +	void *cb_data;
> +};

Why two exactly same structures? Why only a single pointer instead? If
it just to enable type-checking callbacks, then thouse could be opaque
or zero-sized structs that would be embedded or casted away in
respective callbacks.

> +
> +/**
> + * struct restart_data - Restart callback argument
> + *
> + * @cb_data: Callback data.
> + * @cmd: Restart command string.
> + * @stop_chain: Further lower priority callbacks won't be executed if set to
> + *		true. Can be changed within callback. Default is false.
> + * @mode: Reboot mode ID.
> + */
> +struct restart_data {
> +	void *cb_data;
> +	const char *cmd;
> +	bool stop_chain;
> +	enum reboot_mode mode;
> +};
> +
> +/**
> + * struct reboot_prep_data - Reboot and shutdown preparation callback argument
> + *
> + * @cb_data: Callback data.
> + * @cmd: Restart command string.
> + * @stop_chain: Further lower priority callbacks won't be executed if set to
> + *		true. Can be changed within callback. Default is false.

Why would we want to stop power-off or erboot chain? If the callback
succeded, then further calls won't be made. If it doesn't succeed, but
possibly breaks the system somehow, it shouldn't return. Then the only
case left would be to just try the next method of shutting down.

> + * @mode: Preparation mode ID.
> + */
> +struct reboot_prep_data {
> +	void *cb_data;
> +	const char *cmd;
> +	bool stop_chain;
> +	enum reboot_prepare_mode mode;
> +};
> +
> +struct sys_off_handler_private_data {
> +	struct notifier_block power_off_nb;
> +	struct notifier_block restart_nb;
> +	struct notifier_block reboot_nb;

What's the difference between restart and reboot?

> +	void (*platform_power_off_cb)(void);
> +	void (*simple_power_off_cb)(void *data);
> +	void *simple_power_off_cb_data;
> +	bool registered;
> +};

BTW, I couldn't find a right description of my idea of unifying the
chains before, so let me sketch it now.

The idea is to have a single system-off chain in which the callback
gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
would be called, and if at least one returned true, then the shutdown
mode would continue. All of PREP_* would be called then. After that
all DO_* would be tried until one doesn't return (succeeded or broke
the system hard). Classic for(;;); could be a final fallback for the
case where arch/machine (lowest priority) call would return instead
of halting the system in machine-dependent way. The QUERY and PREP
stages could be combined, but I haven't thought about it enough to
see what conditions would need to be imposed on the callbacks in
that case (maybe it's not worth the trouble, since it isn't a fast
path anyway?). The goal here is to have less (duplicated) code in
kernel, but otherwise it seems equivalent to your API proposal.

Best Regards
Micha³ Miros³aw

Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

09.01.2022 02:35, Michał Mirosław пишет:
> On Mon, Dec 13, 2021 at 12:02:52AM +0300, Dmitry Osipenko wrote:
> [...]
>> +/**
>> + * struct power_off_data - Power-off callback argument
>> + *
>> + * @cb_data: Callback data.
>> + */
>> +struct power_off_data {
>> +	void *cb_data;
>> +};
>> +
>> +/**
>> + * struct power_off_prep_data - Power-off preparation callback argument
>> + *
>> + * @cb_data: Callback data.
>> + */
>> +struct power_off_prep_data {
>> +	void *cb_data;
>> +};
> 
> Why two exactly same structures? Why only a single pointer instead? If
> it just to enable type-checking callbacks, then thouse could be opaque
> or zero-sized structs that would be embedded or casted away in
> respective callbacks.

Preparation and final execution are two different operations, it's much
cleaner from a user's perspective to have same separated, IMO. In the
future we may would want to extend one of the structs, and not the
other. Type-checking is another benefit, of course.

The single callback pointer is what is utilized by all current kernel
users. This may change in the future and then it won't be a problem to
extend the power-off API without disrupting whole kernel.

>> +
>> +/**
>> + * struct restart_data - Restart callback argument
>> + *
>> + * @cb_data: Callback data.
>> + * @cmd: Restart command string.
>> + * @stop_chain: Further lower priority callbacks won't be executed if set to
>> + *		true. Can be changed within callback. Default is false.
>> + * @mode: Reboot mode ID.
>> + */
>> +struct restart_data {
>> +	void *cb_data;
>> +	const char *cmd;
>> +	bool stop_chain;
>> +	enum reboot_mode mode;
>> +};
>> +
>> +/**
>> + * struct reboot_prep_data - Reboot and shutdown preparation callback argument
>> + *
>> + * @cb_data: Callback data.
>> + * @cmd: Restart command string.
>> + * @stop_chain: Further lower priority callbacks won't be executed if set to
>> + *		true. Can be changed within callback. Default is false.
> 
> Why would we want to stop power-off or erboot chain? If the callback
> succeded, then further calls won't be made. If it doesn't succeed, but
> possibly breaks the system somehow, it shouldn't return. Then the only
> case left would be to just try the next method of shutting down.

This is what some of the API users were doing for years. I don't know
for sure why they want to stop the chain, it indeed looks like an
incorrect behaviour, but that's up to developers to decide. I only
retained the old behaviour for those users.

>> + * @mode: Preparation mode ID.
>> + */
>> +struct reboot_prep_data {
>> +	void *cb_data;
>> +	const char *cmd;
>> +	bool stop_chain;
>> +	enum reboot_prepare_mode mode;
>> +};
>> +
>> +struct sys_off_handler_private_data {
>> +	struct notifier_block power_off_nb;
>> +	struct notifier_block restart_nb;
>> +	struct notifier_block reboot_nb;
> 
> What's the difference between restart and reboot?

Reboot is always executed before restart and power-off callbacks. This
is explained in the doc-comment of the struct sys_off_handler.

+ * @reboot_prepare_cb: Reboot/shutdown preparation callback. All reboot
+ * preparation callbacks are invoked before @restart_cb or @power_off_cb,
+ * depending on the mode. It's registered with register_reboot_notifier().
+ * The point is to remove boilerplate code from drivers which use this
+ * callback in conjunction with the restart/power-off callbacks.
+ *

This reboot callback usually performs early preparations that are need
to be done before machine is placed into reset state, please see [1] for
the examples.

[1] https://elixir.bootlin.com/linux/v5.16/A/ident/register_reboot_notifier

I agree that "reboot" sounds like a misnomer. This name was coined long
time ago, perhaps not worth to rename it at this point. I'm also not
sure what could be a better name.

>> +	void (*platform_power_off_cb)(void);
>> +	void (*simple_power_off_cb)(void *data);
>> +	void *simple_power_off_cb_data;
>> +	bool registered;
>> +};
> 
> BTW, I couldn't find a right description of my idea of unifying the
> chains before, so let me sketch it now.
> 
> The idea is to have a single system-off chain in which the callback
> gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
> The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
> would be called, and if at least one returned true, then the shutdown
> mode would continue. All of PREP_* would be called then. After that
> all DO_* would be tried until one doesn't return (succeeded or broke
> the system hard). Classic for(;;); could be a final fallback for the
> case where arch/machine (lowest priority) call would return instead
> of halting the system in machine-dependent way. The QUERY and PREP
> stages could be combined, but I haven't thought about it enough to
> see what conditions would need to be imposed on the callbacks in
> that case (maybe it's not worth the trouble, since it isn't a fast
> path anyway?). The goal here is to have less (duplicated) code in
> kernel, but otherwise it seems equivalent to your API proposal.

Michał, thank you for the review and suggestions! I'll take another look
at yours proposal during this merge window, in a preparation to v6.

Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

09.01.2022 02:35, Michał Mirosław пишет:
> On Mon, Dec 13, 2021 at 12:02:52AM +0300, Dmitry Osipenko wrote:
> [...]
>> +/**
>> + * struct power_off_data - Power-off callback argument
>> + *
>> + * @cb_data: Callback data.
>> + */
>> +struct power_off_data {
>> +	void *cb_data;
>> +};
>> +
>> +/**
>> + * struct power_off_prep_data - Power-off preparation callback argument
>> + *
>> + * @cb_data: Callback data.
>> + */
>> +struct power_off_prep_data {
>> +	void *cb_data;
>> +};
> 
> Why two exactly same structures? Why only a single pointer instead? If
> it just to enable type-checking callbacks, then thouse could be opaque
> or zero-sized structs that would be embedded or casted away in
> respective callbacks.

Preparation and final execution are two different operations, it's much
cleaner from a user's perspective to have same separated, IMO. In the
future we may would want to extend one of the structs, and not the
other. Type-checking is another benefit, of course.

The single callback pointer is what is utilized by all current kernel
users. This may change in the future and then it won't be a problem to
extend the power-off API without disrupting whole kernel.

>> +
>> +/**
>> + * struct restart_data - Restart callback argument
>> + *
>> + * @cb_data: Callback data.
>> + * @cmd: Restart command string.
>> + * @stop_chain: Further lower priority callbacks won't be executed if set to
>> + *		true. Can be changed within callback. Default is false.
>> + * @mode: Reboot mode ID.
>> + */
>> +struct restart_data {
>> +	void *cb_data;
>> +	const char *cmd;
>> +	bool stop_chain;
>> +	enum reboot_mode mode;
>> +};
>> +
>> +/**
>> + * struct reboot_prep_data - Reboot and shutdown preparation callback argument
>> + *
>> + * @cb_data: Callback data.
>> + * @cmd: Restart command string.
>> + * @stop_chain: Further lower priority callbacks won't be executed if set to
>> + *		true. Can be changed within callback. Default is false.
> 
> Why would we want to stop power-off or erboot chain? If the callback
> succeded, then further calls won't be made. If it doesn't succeed, but
> possibly breaks the system somehow, it shouldn't return. Then the only
> case left would be to just try the next method of shutting down.

This is what some of the API users were doing for years. I don't know
for sure why they want to stop the chain, it indeed looks like an
incorrect behaviour, but that's up to developers to decide. I only
retained the old behaviour for those users.

>> + * @mode: Preparation mode ID.
>> + */
>> +struct reboot_prep_data {
>> +	void *cb_data;
>> +	const char *cmd;
>> +	bool stop_chain;
>> +	enum reboot_prepare_mode mode;
>> +};
>> +
>> +struct sys_off_handler_private_data {
>> +	struct notifier_block power_off_nb;
>> +	struct notifier_block restart_nb;
>> +	struct notifier_block reboot_nb;
> 
> What's the difference between restart and reboot?

Reboot is always executed before restart and power-off callbacks. This
is explained in the doc-comment of the struct sys_off_handler.

+ * @reboot_prepare_cb: Reboot/shutdown preparation callback. All reboot
+ * preparation callbacks are invoked before @restart_cb or @power_off_cb,
+ * depending on the mode. It's registered with register_reboot_notifier().
+ * The point is to remove boilerplate code from drivers which use this
+ * callback in conjunction with the restart/power-off callbacks.
+ *

This reboot callback usually performs early preparations that are need
to be done before machine is placed into reset state, please see [1] for
the examples.

[1] https://elixir.bootlin.com/linux/v5.16/A/ident/register_reboot_notifier

I agree that "reboot" sounds like a misnomer. This name was coined long
time ago, perhaps not worth to rename it at this point. I'm also not
sure what could be a better name.

>> +	void (*platform_power_off_cb)(void);
>> +	void (*simple_power_off_cb)(void *data);
>> +	void *simple_power_off_cb_data;
>> +	bool registered;
>> +};
> 
> BTW, I couldn't find a right description of my idea of unifying the
> chains before, so let me sketch it now.
> 
> The idea is to have a single system-off chain in which the callback
> gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
> The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
> would be called, and if at least one returned true, then the shutdown
> mode would continue. All of PREP_* would be called then. After that
> all DO_* would be tried until one doesn't return (succeeded or broke
> the system hard). Classic for(;;); could be a final fallback for the
> case where arch/machine (lowest priority) call would return instead
> of halting the system in machine-dependent way. The QUERY and PREP
> stages could be combined, but I haven't thought about it enough to
> see what conditions would need to be imposed on the callbacks in
> that case (maybe it's not worth the trouble, since it isn't a fast
> path anyway?). The goal here is to have less (duplicated) code in
> kernel, but otherwise it seems equivalent to your API proposal.

Michał, thank you for the review and suggestions! I'll take another look
at yours proposal during this merge window, in a preparation to v6.

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linux-riscv@lists.infradead.org
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Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

09.01.2022 02:35, Michał Mirosław пишет:
> On Mon, Dec 13, 2021 at 12:02:52AM +0300, Dmitry Osipenko wrote:
> [...]
>> +/**
>> + * struct power_off_data - Power-off callback argument
>> + *
>> + * @cb_data: Callback data.
>> + */
>> +struct power_off_data {
>> +	void *cb_data;
>> +};
>> +
>> +/**
>> + * struct power_off_prep_data - Power-off preparation callback argument
>> + *
>> + * @cb_data: Callback data.
>> + */
>> +struct power_off_prep_data {
>> +	void *cb_data;
>> +};
> 
> Why two exactly same structures? Why only a single pointer instead? If
> it just to enable type-checking callbacks, then thouse could be opaque
> or zero-sized structs that would be embedded or casted away in
> respective callbacks.

Preparation and final execution are two different operations, it's much
cleaner from a user's perspective to have same separated, IMO. In the
future we may would want to extend one of the structs, and not the
other. Type-checking is another benefit, of course.

The single callback pointer is what is utilized by all current kernel
users. This may change in the future and then it won't be a problem to
extend the power-off API without disrupting whole kernel.

>> +
>> +/**
>> + * struct restart_data - Restart callback argument
>> + *
>> + * @cb_data: Callback data.
>> + * @cmd: Restart command string.
>> + * @stop_chain: Further lower priority callbacks won't be executed if set to
>> + *		true. Can be changed within callback. Default is false.
>> + * @mode: Reboot mode ID.
>> + */
>> +struct restart_data {
>> +	void *cb_data;
>> +	const char *cmd;
>> +	bool stop_chain;
>> +	enum reboot_mode mode;
>> +};
>> +
>> +/**
>> + * struct reboot_prep_data - Reboot and shutdown preparation callback argument
>> + *
>> + * @cb_data: Callback data.
>> + * @cmd: Restart command string.
>> + * @stop_chain: Further lower priority callbacks won't be executed if set to
>> + *		true. Can be changed within callback. Default is false.
> 
> Why would we want to stop power-off or erboot chain? If the callback
> succeded, then further calls won't be made. If it doesn't succeed, but
> possibly breaks the system somehow, it shouldn't return. Then the only
> case left would be to just try the next method of shutting down.

This is what some of the API users were doing for years. I don't know
for sure why they want to stop the chain, it indeed looks like an
incorrect behaviour, but that's up to developers to decide. I only
retained the old behaviour for those users.

>> + * @mode: Preparation mode ID.
>> + */
>> +struct reboot_prep_data {
>> +	void *cb_data;
>> +	const char *cmd;
>> +	bool stop_chain;
>> +	enum reboot_prepare_mode mode;
>> +};
>> +
>> +struct sys_off_handler_private_data {
>> +	struct notifier_block power_off_nb;
>> +	struct notifier_block restart_nb;
>> +	struct notifier_block reboot_nb;
> 
> What's the difference between restart and reboot?

Reboot is always executed before restart and power-off callbacks. This
is explained in the doc-comment of the struct sys_off_handler.

+ * @reboot_prepare_cb: Reboot/shutdown preparation callback. All reboot
+ * preparation callbacks are invoked before @restart_cb or @power_off_cb,
+ * depending on the mode. It's registered with register_reboot_notifier().
+ * The point is to remove boilerplate code from drivers which use this
+ * callback in conjunction with the restart/power-off callbacks.
+ *

This reboot callback usually performs early preparations that are need
to be done before machine is placed into reset state, please see [1] for
the examples.

[1] https://elixir.bootlin.com/linux/v5.16/A/ident/register_reboot_notifier

I agree that "reboot" sounds like a misnomer. This name was coined long
time ago, perhaps not worth to rename it at this point. I'm also not
sure what could be a better name.

>> +	void (*platform_power_off_cb)(void);
>> +	void (*simple_power_off_cb)(void *data);
>> +	void *simple_power_off_cb_data;
>> +	bool registered;
>> +};
> 
> BTW, I couldn't find a right description of my idea of unifying the
> chains before, so let me sketch it now.
> 
> The idea is to have a single system-off chain in which the callback
> gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
> The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
> would be called, and if at least one returned true, then the shutdown
> mode would continue. All of PREP_* would be called then. After that
> all DO_* would be tried until one doesn't return (succeeded or broke
> the system hard). Classic for(;;); could be a final fallback for the
> case where arch/machine (lowest priority) call would return instead
> of halting the system in machine-dependent way. The QUERY and PREP
> stages could be combined, but I haven't thought about it enough to
> see what conditions would need to be imposed on the callbacks in
> that case (maybe it's not worth the trouble, since it isn't a fast
> path anyway?). The goal here is to have less (duplicated) code in
> kernel, but otherwise it seems equivalent to your API proposal.

Michał, thank you for the review and suggestions! I'll take another look
at yours proposal during this merge window, in a preparation to v6.

Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

09.01.2022 02:35, Michał Mirosław пишет:
> On Mon, Dec 13, 2021 at 12:02:52AM +0300, Dmitry Osipenko wrote:
> [...]
>> +/**
>> + * struct power_off_data - Power-off callback argument
>> + *
>> + * @cb_data: Callback data.
>> + */
>> +struct power_off_data {
>> +	void *cb_data;
>> +};
>> +
>> +/**
>> + * struct power_off_prep_data - Power-off preparation callback argument
>> + *
>> + * @cb_data: Callback data.
>> + */
>> +struct power_off_prep_data {
>> +	void *cb_data;
>> +};
> 
> Why two exactly same structures? Why only a single pointer instead? If
> it just to enable type-checking callbacks, then thouse could be opaque
> or zero-sized structs that would be embedded or casted away in
> respective callbacks.

Preparation and final execution are two different operations, it's much
cleaner from a user's perspective to have same separated, IMO. In the
future we may would want to extend one of the structs, and not the
other. Type-checking is another benefit, of course.

The single callback pointer is what is utilized by all current kernel
users. This may change in the future and then it won't be a problem to
extend the power-off API without disrupting whole kernel.

>> +
>> +/**
>> + * struct restart_data - Restart callback argument
>> + *
>> + * @cb_data: Callback data.
>> + * @cmd: Restart command string.
>> + * @stop_chain: Further lower priority callbacks won't be executed if set to
>> + *		true. Can be changed within callback. Default is false.
>> + * @mode: Reboot mode ID.
>> + */
>> +struct restart_data {
>> +	void *cb_data;
>> +	const char *cmd;
>> +	bool stop_chain;
>> +	enum reboot_mode mode;
>> +};
>> +
>> +/**
>> + * struct reboot_prep_data - Reboot and shutdown preparation callback argument
>> + *
>> + * @cb_data: Callback data.
>> + * @cmd: Restart command string.
>> + * @stop_chain: Further lower priority callbacks won't be executed if set to
>> + *		true. Can be changed within callback. Default is false.
> 
> Why would we want to stop power-off or erboot chain? If the callback
> succeded, then further calls won't be made. If it doesn't succeed, but
> possibly breaks the system somehow, it shouldn't return. Then the only
> case left would be to just try the next method of shutting down.

This is what some of the API users were doing for years. I don't know
for sure why they want to stop the chain, it indeed looks like an
incorrect behaviour, but that's up to developers to decide. I only
retained the old behaviour for those users.

>> + * @mode: Preparation mode ID.
>> + */
>> +struct reboot_prep_data {
>> +	void *cb_data;
>> +	const char *cmd;
>> +	bool stop_chain;
>> +	enum reboot_prepare_mode mode;
>> +};
>> +
>> +struct sys_off_handler_private_data {
>> +	struct notifier_block power_off_nb;
>> +	struct notifier_block restart_nb;
>> +	struct notifier_block reboot_nb;
> 
> What's the difference between restart and reboot?

Reboot is always executed before restart and power-off callbacks. This
is explained in the doc-comment of the struct sys_off_handler.

+ * @reboot_prepare_cb: Reboot/shutdown preparation callback. All reboot
+ * preparation callbacks are invoked before @restart_cb or @power_off_cb,
+ * depending on the mode. It's registered with register_reboot_notifier().
+ * The point is to remove boilerplate code from drivers which use this
+ * callback in conjunction with the restart/power-off callbacks.
+ *

This reboot callback usually performs early preparations that are need
to be done before machine is placed into reset state, please see [1] for
the examples.

[1] https://elixir.bootlin.com/linux/v5.16/A/ident/register_reboot_notifier

I agree that "reboot" sounds like a misnomer. This name was coined long
time ago, perhaps not worth to rename it at this point. I'm also not
sure what could be a better name.

>> +	void (*platform_power_off_cb)(void);
>> +	void (*simple_power_off_cb)(void *data);
>> +	void *simple_power_off_cb_data;
>> +	bool registered;
>> +};
> 
> BTW, I couldn't find a right description of my idea of unifying the
> chains before, so let me sketch it now.
> 
> The idea is to have a single system-off chain in which the callback
> gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
> The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
> would be called, and if at least one returned true, then the shutdown
> mode would continue. All of PREP_* would be called then. After that
> all DO_* would be tried until one doesn't return (succeeded or broke
> the system hard). Classic for(;;); could be a final fallback for the
> case where arch/machine (lowest priority) call would return instead
> of halting the system in machine-dependent way. The QUERY and PREP
> stages could be combined, but I haven't thought about it enough to
> see what conditions would need to be imposed on the callbacks in
> that case (maybe it's not worth the trouble, since it isn't a fast
> path anyway?). The goal here is to have less (duplicated) code in
> kernel, but otherwise it seems equivalent to your API proposal.

Michał, thank you for the review and suggestions! I'll take another look
at yours proposal during this merge window, in a preparation to v6.

Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

Hello Michał,

09.01.2022 02:35, Michał Mirosław пишет:
> BTW, I couldn't find a right description of my idea of unifying the
> chains before, so let me sketch it now.
> 
> The idea is to have a single system-off chain in which the callback
> gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
> The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
> would be called, and if at least one returned true, then the shutdown
> mode would continue. All of PREP_* would be called then. After that
> all DO_* would be tried until one doesn't return (succeeded or broke
> the system hard). Classic for(;;); could be a final fallback for the
> case where arch/machine (lowest priority) call would return instead
> of halting the system in machine-dependent way. The QUERY and PREP
> stages could be combined, but I haven't thought about it enough to
> see what conditions would need to be imposed on the callbacks in
> that case (maybe it's not worth the trouble, since it isn't a fast
> path anyway?). The goal here is to have less (duplicated) code in
> kernel, but otherwise it seems equivalent to your API proposal.

Thank you again for yours proposal! IMO, it's much more important to
keep the core code simple and maintainable, rather than try to optimize
it without a very good reason, given that this isn't a hot code path at
all and saving a couple of bytes won't be noticeable. The poweroff,
restart and reboot were separated before this series and I'm finding
that it's easier to follow the code when it's structured that way. I'm
not convinced that we need to change it.

Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

Hello Michał,

09.01.2022 02:35, Michał Mirosław пишет:
> BTW, I couldn't find a right description of my idea of unifying the
> chains before, so let me sketch it now.
> 
> The idea is to have a single system-off chain in which the callback
> gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
> The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
> would be called, and if at least one returned true, then the shutdown
> mode would continue. All of PREP_* would be called then. After that
> all DO_* would be tried until one doesn't return (succeeded or broke
> the system hard). Classic for(;;); could be a final fallback for the
> case where arch/machine (lowest priority) call would return instead
> of halting the system in machine-dependent way. The QUERY and PREP
> stages could be combined, but I haven't thought about it enough to
> see what conditions would need to be imposed on the callbacks in
> that case (maybe it's not worth the trouble, since it isn't a fast
> path anyway?). The goal here is to have less (duplicated) code in
> kernel, but otherwise it seems equivalent to your API proposal.

Thank you again for yours proposal! IMO, it's much more important to
keep the core code simple and maintainable, rather than try to optimize
it without a very good reason, given that this isn't a hot code path at
all and saving a couple of bytes won't be noticeable. The poweroff,
restart and reboot were separated before this series and I'm finding
that it's easier to follow the code when it's structured that way. I'm
not convinced that we need to change it.

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Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

Hello Michał,

09.01.2022 02:35, Michał Mirosław пишет:
> BTW, I couldn't find a right description of my idea of unifying the
> chains before, so let me sketch it now.
> 
> The idea is to have a single system-off chain in which the callback
> gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
> The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
> would be called, and if at least one returned true, then the shutdown
> mode would continue. All of PREP_* would be called then. After that
> all DO_* would be tried until one doesn't return (succeeded or broke
> the system hard). Classic for(;;); could be a final fallback for the
> case where arch/machine (lowest priority) call would return instead
> of halting the system in machine-dependent way. The QUERY and PREP
> stages could be combined, but I haven't thought about it enough to
> see what conditions would need to be imposed on the callbacks in
> that case (maybe it's not worth the trouble, since it isn't a fast
> path anyway?). The goal here is to have less (duplicated) code in
> kernel, but otherwise it seems equivalent to your API proposal.

Thank you again for yours proposal! IMO, it's much more important to
keep the core code simple and maintainable, rather than try to optimize
it without a very good reason, given that this isn't a hot code path at
all and saving a couple of bytes won't be noticeable. The poweroff,
restart and reboot were separated before this series and I'm finding
that it's easier to follow the code when it's structured that way. I'm
not convinced that we need to change it.

Re: [PATCH v5 04/21] kernel: Add combined power-off+restart handler call chain API

[Dmitry Osipenko]

Hello Michał,

09.01.2022 02:35, Michał Mirosław пишет:
> BTW, I couldn't find a right description of my idea of unifying the
> chains before, so let me sketch it now.
> 
> The idea is to have a single system-off chain in which the callback
> gets a mode ({QUERY_*, PREP_*, DO_*} for each of {*_REBOOT, *_POWEROFF, ...?).
> The QUERY_* calls would be made in can_kernel_reboot/poweroff(): all
> would be called, and if at least one returned true, then the shutdown
> mode would continue. All of PREP_* would be called then. After that
> all DO_* would be tried until one doesn't return (succeeded or broke
> the system hard). Classic for(;;); could be a final fallback for the
> case where arch/machine (lowest priority) call would return instead
> of halting the system in machine-dependent way. The QUERY and PREP
> stages could be combined, but I haven't thought about it enough to
> see what conditions would need to be imposed on the callbacks in
> that case (maybe it's not worth the trouble, since it isn't a fast
> path anyway?). The goal here is to have less (duplicated) code in
> kernel, but otherwise it seems equivalent to your API proposal.

Thank you again for yours proposal! IMO, it's much more important to
keep the core code simple and maintainable, rather than try to optimize
it without a very good reason, given that this isn't a hot code path at
all and saving a couple of bytes won't be noticeable. The poweroff,
restart and reboot were separated before this series and I'm finding
that it's easier to follow the code when it's structured that way. I'm
not convinced that we need to change it.