Re: [PATCH V12 00/14] Krait clocks + Krait CPUfreq

[Sricharan R <sricharan@codeaurora.org>]

Hi Craig,

On 8/14/2018 5:42 PM, Sricharan R wrote:
> [v12]
>   * Added my signed-off that was missing in some patches.
>   * Added Bjorn's acked that i missed earlier.
> 

  Can you give this a try on your 8974 device and check if the
  pvs version reporting, scaling for higher frequencies are fine ?
  Sorry, i could not get hold of a 8974 device. So in-case if you still
  have the issues with higher frequencies, can you give a quick debug
  and report. That would be of great help.

Regards,
 Sricharan


> [v11]
>   * Dropped patch 13 and 14 from v10 and
>     merged the qcom-cpufreq-krait driver to the existing qcom-cpufreq-kryo.c
>   * Rebased on top of clk-next
>   * Fixed a bug while populating the pvs version for krait.
> 
> [v10]
>   * Addressed Stephen's comments to add clocks bindings properties
>     to the newly introduced nodes.
>   * Added a change to include opp-supported-hw to qcom-cpufreq.c
>   * Rebased on top of clk-next
>   * Although there were minor changes to bindings and the driver
>     retained the acked-by tags from Rob and Viresh respectively.    
> 
> [v9]
>   * Fixed a rebase issue in Makefile and added Tag from Robh.
> 
> [v8]
>   * Fixed a bug in path#14 pointed out by Viresh and also added tags.
>     No change in any other patch.
> 
> [v7]
>   * Fixed comments from Viresh for cleaning up the error handling
>     in qcom-cpufreq.c. Also changed the init function to lateinit
>     call. This is required because nvmem which gets initialised with
>     module_init needs to go first.
>   * Fixed Rob's comments for bindings documentation
>   * Fixed kbuild build issue in clk-lpc32xx.c
>   * Rebased on top of clk-next
> 
> [v6]
>   * Adrressed comments from Viresh for patch #14 in v5 [5]
>   * Introduced a new binding operating-points-v2-krait-cpu
>     as per discussion with Rob
>   * Added Review tags
> 
> [v5]
>   * Addressed comments from Rob for bindings
>   * Addressed comments from Viresh to use dev_pm_opp_set_prop_name, accordingly
>     dropped patch #12 and corrected patch #11 from previous patch set in [4]
>   * Converted to use #spdx tags for newly introduced files
> 
> Mostly a resend of the v3 posted by Stephen quite some time back [1]
> except for few changes.
>   Based on reading some feedback from list,
>   * Dropped the patch "clk: Add safe switch hook" from v3 [2].
>     Now this is taken care by patch#10 in this series only for Krait.
>   * Dropped the path "clk: Avoid sending high rates to downstream
> 		      clocks during set_rate" from v3 [3].
>   * Rebased on top of clk-next.
>   * Dropped the DT update from the series. Will send separately
>   * Now with cpufreq-dt+opp supporting voltage scaling, registering the
>     krait cpu supplies in DT should be sufficient. But one issue is,
>     the qcom-cpufreq drivers reads the efuse and based on that registers
>     the opp data and then registers the cpufreq-dt device. So when
>     cpufreq-dt driver probes and registers the regulator to the OPP framework,
>     it expects that the opp data for the device should not be registered before
>     the regulator. Will send a RFC patch removing that check, to find out the
>     right way of doing it.
> 
> These patches provide cpufreq scaling on devices with Krait CPUs.
> In Krait CPU designs there's one PLL and two muxes per CPU, allowing
> us to switch CPU frequencies independently.
> 
> 				 secondary
> 	 +-----+                    +
> 	 | QSB |-------+------------|\
> 	 +-----+       |            | |-+
> 		       |    +-------|/  |
> 		       |    |       +   |
> 	 +-----+       |    |           |
> 	 | PLL |----+-------+           |   primary
> 	 +-----+    |  |                |     +
> 		    |  |                +-----|\       +------+
> 	 +-------+  |  |                      | \      |      |
> 	 | HFPLL |----------+-----------------|  |-----| CPU0 |
> 	 +-------+  |  |    |                 |  |     |      |
> 		    |  |    | +-----+         | /      +------+
> 		    |  |    +-| / 2 |---------|/
> 		    |  |      +-----+         +
> 		    |  |         secondary
> 		    |  |            +
> 		    |  +------------|\
> 		    |               | |-+
> 		    +---------------|/  |   primary
> 				    +   |     +
> 					+-----|\       +------+
> 	 +-------+                            | \      |      |
> 	 | HFPLL |----------------------------|  |-----| CPU1 |
> 	 +-------+          |                 |  |     |      |
> 			    | +-----+         | /      +------+
> 			    +-| / 2 |---------|/
> 			      +-----+         +
> 
> To support this in the common clock framework we model the muxes,
> dividers, and PLLs as different clocks. CPUfreq only interacts
> with the primary mux (farthest right in the diagram). When CPUfreq
> sets a rate, the mux code finds the best parent that can provide the rate.
> Due to the design, QSB and the top PLL are always a fixed rate and thus
> only support one frequency each. These sources provide the lowest
> frequencies for the CPUs. The HFPLLs are where we can make the CPU go
> faster (GHz range). Sometimes we need to run the HFPLL twice as
> fast and divide it by two to get a particular frequency.
> 
> When switching rates we can't leave the CPU clocked by the HFPLL because
> we need to turn off the output of the PLL when changing its frequency.
> This means we have to switch over to the secondary mux and use one of the
> fixed sources. This is why we need something like the safe parent patch.
> 
> [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/332607.html
> [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/332615.html
> [3] http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/332608.html
> [4] https://lwn.net/Articles/740994/ 
> [5] https://lkml.org/lkml/2017/12/19/537
> 
> 
> Sricharan R (3):
>   clk: qcom: Add safe switch hook for krait mux clocks
>   cpufreq: qcom: Re-organise kryo cpufreq to use it for other nvmem
>     based qcom socs
>   cpufreq: qcom: Add support for krait based socs
> 
> Stephen Boyd (11):
>   ARM: Add Krait L2 register accessor functions
>   clk: qcom: Add support for High-Frequency PLLs (HFPLLs)
>   clk: qcom: Add HFPLL driver
>   dt-bindings: clock: Document qcom,hfpll
>   clk: qcom: Add MSM8960/APQ8064's HFPLLs
>   clk: qcom: Add IPQ806X's HFPLLs
>   clk: qcom: Add support for Krait clocks
>   clk: qcom: Add KPSS ACC/GCC driver
>   dt-bindings: arm: Document qcom,kpss-gcc
>   clk: qcom: Add Krait clock controller driver
>   dt-bindings: clock: Document qcom,krait-cc
> 
>  .../devicetree/bindings/arm/msm/qcom,kpss-acc.txt  |  19 +
>  .../devicetree/bindings/arm/msm/qcom,kpss-gcc.txt  |  44 +++
>  .../devicetree/bindings/clock/qcom,hfpll.txt       |  60 ++++
>  .../devicetree/bindings/clock/qcom,krait-cc.txt    |  34 ++
>  .../{kryo-cpufreq.txt => qcom-nvmem-cpufreq.txt}   |   7 +-
>  arch/arm/common/Kconfig                            |   3 +
>  arch/arm/common/Makefile                           |   1 +
>  arch/arm/common/krait-l2-accessors.c               |  48 +++
>  arch/arm/include/asm/krait-l2-accessors.h          |   9 +
>  drivers/clk/qcom/Kconfig                           |  28 ++
>  drivers/clk/qcom/Makefile                          |   5 +
>  drivers/clk/qcom/clk-hfpll.c                       | 244 +++++++++++++
>  drivers/clk/qcom/clk-hfpll.h                       |  44 +++
>  drivers/clk/qcom/clk-krait.c                       | 126 +++++++
>  drivers/clk/qcom/clk-krait.h                       |  40 +++
>  drivers/clk/qcom/gcc-ipq806x.c                     |  82 +++++
>  drivers/clk/qcom/gcc-msm8960.c                     | 172 +++++++++
>  drivers/clk/qcom/hfpll.c                           |  96 +++++
>  drivers/clk/qcom/kpss-xcc.c                        |  87 +++++
>  drivers/clk/qcom/krait-cc.c                        | 397 +++++++++++++++++++++
>  drivers/cpufreq/Kconfig.arm                        |   6 +-
>  drivers/cpufreq/Makefile                           |   2 +-
>  drivers/cpufreq/cpufreq-dt-platdev.c               |   5 +
>  drivers/cpufreq/qcom-cpufreq-kryo.c                | 232 ------------
>  drivers/cpufreq/qcom-cpufreq-nvmem.c               | 387 ++++++++++++++++++++
>  include/dt-bindings/clock/qcom,gcc-msm8960.h       |   2 +
>  26 files changed, 1941 insertions(+), 239 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/arm/msm/qcom,kpss-gcc.txt
>  create mode 100644 Documentation/devicetree/bindings/clock/qcom,hfpll.txt
>  create mode 100644 Documentation/devicetree/bindings/clock/qcom,krait-cc.txt
>  rename Documentation/devicetree/bindings/opp/{kryo-cpufreq.txt => qcom-nvmem-cpufreq.txt} (98%)
>  create mode 100644 arch/arm/common/krait-l2-accessors.c
>  create mode 100644 arch/arm/include/asm/krait-l2-accessors.h
>  create mode 100644 drivers/clk/qcom/clk-hfpll.c
>  create mode 100644 drivers/clk/qcom/clk-hfpll.h
>  create mode 100644 drivers/clk/qcom/clk-krait.c
>  create mode 100644 drivers/clk/qcom/clk-krait.h
>  create mode 100644 drivers/clk/qcom/hfpll.c
>  create mode 100644 drivers/clk/qcom/kpss-xcc.c
>  create mode 100644 drivers/clk/qcom/krait-cc.c
>  delete mode 100644 drivers/cpufreq/qcom-cpufreq-kryo.c
>  create mode 100644 drivers/cpufreq/qcom-cpufreq-nvmem.c
> 

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