[PATCH 00/14] PM: SoC idle support using PM domains

[PATCH 00/14] PM: SoC idle support using PM domains

[Lina Iyer]

Hi all,

Changes since RFC-v3:
- Reorganize the patches. Documentations have their own patch.
- Moved code around with PSCI OS initiated so they would not have compiler
  errors in other configuration.
- Minor bug fixes with genpd power_on functionality.
- Rebased on top of 4.7-rc1

This is the submission of the SoC idle support in the kernel for CPU domains
using genpd. The patches were submitted as RFC's earlier, the last of them is
[1]. Since the RFC, multiple discussions have happened around making the
patches generic across all architectures. For now, the patches address the
needs of the ARM community, but sure enough can be extended to support other
architectures. Some of the limitations in making this patch generic is the lack
of device idle state description in the DT, but that in itself is a bigger
topic for a future discussion.
 
The patch has been tested on the 410c Dragonboard and the MTK EVB boards. Both
show good power savings when used with OS Initiated PSCI f/w.

Ulf is maintaining a branch tracking the PM/genpd changes that are in
pipleline. This series sits well on his branch. You may find the entire series
at [2].

Thanks,
Lina

[1]. http://lists.infradead.org/pipermail/linux-arm-kernel/2016-March/412934.html
[2]. https://git.linaro.org/people/lina.iyer/linux-next.git/shortlog/refs/heads/genpd-psci-v1

Axel Haslam (2):
  PM / Domains: Allow domain power states to be read from DT
  dt/bindings: update binding for PM domain idle states

Lina Iyer (12):
  PM / Domains: Abstract genpd locking
  PM / Domains: Support IRQ safe PM domains
  PM / doc: update device documentation for devices in IRQ safe PM
    domains
  PM / cpu_domains: Setup PM domains for CPUs/clusters
  ARM: cpuidle: Add runtime PM support for CPUs
  timer: Export next wake up of a CPU
  PM / cpu_domains: Add PM Domain governor for CPUs
  doc / cpu_domains: Describe CPU PM domains setup and governor
  drivers: firmware: psci: Allow OS Initiated suspend mode
  drivers: firmware: psci: Support cluster idle states for OS-Initiated
  ARM64: dts: Add PSCI cpuidle support for MSM8916
  ARM64: dts: Define CPU power domain for MSM8916

 .../devicetree/bindings/power/power_domain.txt     |  70 ++++
 Documentation/power/cpu_domains.txt                |  79 +++++
 Documentation/power/devices.txt                    |  12 +-
 arch/arm64/boot/dts/qcom/msm8916.dtsi              |  49 +++
 drivers/base/power/Makefile                        |   1 +
 drivers/base/power/cpu_domains.c                   | 366 +++++++++++++++++++++
 drivers/base/power/domain.c                        | 300 ++++++++++++++---
 drivers/cpuidle/cpuidle-arm.c                      |  55 ++++
 drivers/firmware/psci.c                            |  92 +++++-
 include/linux/cpu_domains.h                        |  37 +++
 include/linux/pm_domain.h                          |  16 +-
 include/linux/tick.h                               |  10 +
 include/uapi/linux/psci.h                          |   5 +
 kernel/time/tick-sched.c                           |  13 +
 14 files changed, 1054 insertions(+), 51 deletions(-)
 create mode 100644 Documentation/power/cpu_domains.txt
 create mode 100644 drivers/base/power/cpu_domains.c
 create mode 100644 include/linux/cpu_domains.h

-- 
2.7.4

[PATCH 00/14] PM: SoC idle support using PM domains

[Lina Iyer]

Hi all,

Changes since RFC-v3:
- Reorganize the patches. Documentations have their own patch.
- Moved code around with PSCI OS initiated so they would not have compiler
  errors in other configuration.
- Minor bug fixes with genpd power_on functionality.
- Rebased on top of 4.7-rc1

This is the submission of the SoC idle support in the kernel for CPU domains
using genpd. The patches were submitted as RFC's earlier, the last of them is
[1]. Since the RFC, multiple discussions have happened around making the
patches generic across all architectures. For now, the patches address the
needs of the ARM community, but sure enough can be extended to support other
architectures. Some of the limitations in making this patch generic is the lack
of device idle state description in the DT, but that in itself is a bigger
topic for a future discussion.
 
The patch has been tested on the 410c Dragonboard and the MTK EVB boards. Both
show good power savings when used with OS Initiated PSCI f/w.

Ulf is maintaining a branch tracking the PM/genpd changes that are in
pipleline. This series sits well on his branch. You may find the entire series
at [2].

Thanks,
Lina

[1]. http://lists.infradead.org/pipermail/linux-arm-kernel/2016-March/412934.html
[2]. https://git.linaro.org/people/lina.iyer/linux-next.git/shortlog/refs/heads/genpd-psci-v1

Axel Haslam (2):
  PM / Domains: Allow domain power states to be read from DT
  dt/bindings: update binding for PM domain idle states

Lina Iyer (12):
  PM / Domains: Abstract genpd locking
  PM / Domains: Support IRQ safe PM domains
  PM / doc: update device documentation for devices in IRQ safe PM
    domains
  PM / cpu_domains: Setup PM domains for CPUs/clusters
  ARM: cpuidle: Add runtime PM support for CPUs
  timer: Export next wake up of a CPU
  PM / cpu_domains: Add PM Domain governor for CPUs
  doc / cpu_domains: Describe CPU PM domains setup and governor
  drivers: firmware: psci: Allow OS Initiated suspend mode
  drivers: firmware: psci: Support cluster idle states for OS-Initiated
  ARM64: dts: Add PSCI cpuidle support for MSM8916
  ARM64: dts: Define CPU power domain for MSM8916

 .../devicetree/bindings/power/power_domain.txt     |  70 ++++
 Documentation/power/cpu_domains.txt                |  79 +++++
 Documentation/power/devices.txt                    |  12 +-
 arch/arm64/boot/dts/qcom/msm8916.dtsi              |  49 +++
 drivers/base/power/Makefile                        |   1 +
 drivers/base/power/cpu_domains.c                   | 366 +++++++++++++++++++++
 drivers/base/power/domain.c                        | 300 ++++++++++++++---
 drivers/cpuidle/cpuidle-arm.c                      |  55 ++++
 drivers/firmware/psci.c                            |  92 +++++-
 include/linux/cpu_domains.h                        |  37 +++
 include/linux/pm_domain.h                          |  16 +-
 include/linux/tick.h                               |  10 +
 include/uapi/linux/psci.h                          |   5 +
 kernel/time/tick-sched.c                           |  13 +
 14 files changed, 1054 insertions(+), 51 deletions(-)
 create mode 100644 Documentation/power/cpu_domains.txt
 create mode 100644 drivers/base/power/cpu_domains.c
 create mode 100644 include/linux/cpu_domains.h

-- 
2.7.4

[PATCH 01/14] PM / Domains: Allow domain power states to be read from DT

[Lina Iyer]

From: Axel Haslam <ahaslam+renesas@baylibre.com>

This patch allows domains to define idle states in the DT. SoC's can
define domain idle states in DT using the "power-states" property of the
domain provider. Calling of_pm_genpd_init() will  read the idle states
and initialize the genpd for the domain.

In addition to the entry and exit latency for idle state, also add
residency and state-param properties. A domain idling in a state is only
power effecient if it stays idle for a certain period in that state. The
residency provides this minimum time for the idle state to provide power
benefits. The state-param is a state specific u32 value that the
platform may use for that idle state.

Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
[Lina: Added state properties, removed state names, wakeup-latency,
added of_pm_genpd_init() API, pruned commit text]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[Ulf: Moved around code to make it compile properly, rebased on top of multiple
state support,changed to use pm_genpd_init()]
---
 drivers/base/power/domain.c | 84 ++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/pm_domain.h   |  3 ++
 2 files changed, 86 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index a1f2aff..62ffabd 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1253,6 +1253,82 @@ out:
 }
 EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
 
+static int genpd_of_get_power_state(struct genpd_power_state *genpd_state,
+				    struct device_node *state_node)
+{
+	int err = 0;
+	u32 latency;
+	u32 residency;
+	u32 param;
+	u32 entry_latency, exit_latency;
+
+	err = of_property_read_u32(state_node, "entry-latency-us",
+				   &entry_latency);
+	if (err) {
+		pr_debug(" * %s missing entry-latency-us property\n",
+			 state_node->full_name);
+		return -EINVAL;
+	}
+
+	err = of_property_read_u32(state_node, "exit-latency-us",
+				   &exit_latency);
+	if (err) {
+		pr_debug(" * %s missing exit-latency-us property\n",
+			 state_node->full_name);
+		return -EINVAL;
+	}
+
+	err = of_property_read_u32(state_node, "residency-us", &residency);
+	if (!err)
+		genpd_state->residency_ns = 1000 * residency;
+
+	err = of_property_read_u32(state_node, "state-param", &param);
+	if (!err)
+		genpd_state->param = param;
+
+	latency = entry_latency + exit_latency;
+	genpd_state->power_on_latency_ns = 1000 * latency;
+	genpd_state->power_off_latency_ns = 1000 * entry_latency;
+
+	return 0;
+}
+
+static int genpd_of_parse_power_states(struct generic_pm_domain *genpd)
+{
+	struct device_node *np;
+	int i, err = 0;
+
+	for (i = 0; i < GENPD_MAX_NUM_STATES; i++) {
+		np = of_parse_phandle(genpd->of_node, "power-states", i);
+		if (!np)
+			break;
+
+		err = genpd_of_get_power_state(&genpd->states[i], np);
+		if (err) {
+			pr_err
+			    ("Parsing idle state node %s failed with err %d\n",
+			     np->full_name, err);
+			err = -EINVAL;
+			break;
+		}
+		of_node_put(np);
+	}
+
+	if (err)
+		return err;
+
+	genpd->state_count = i;
+	return 0;
+}
+
+static int genpd_of_parse(struct generic_pm_domain *genpd)
+{
+	if (!genpd->of_node)
+		return 0;
+
+	return genpd_of_parse_power_states(genpd);
+}
+
 /**
  * pm_genpd_init - Initialize a generic I/O PM domain object.
  * @genpd: PM domain object to initialize.
@@ -1262,8 +1338,10 @@ EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
  * Returns 0 on successful initialization, else a negative error code.
  */
 int pm_genpd_init(struct generic_pm_domain *genpd,
-		  struct dev_power_governor *gov, bool is_off)
+		   struct dev_power_governor *gov, bool is_off)
 {
+	int ret;
+
 	if (IS_ERR_OR_NULL(genpd))
 		return -EINVAL;
 
@@ -1306,6 +1384,10 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 		genpd->dev_ops.start = pm_clk_resume;
 	}
 
+	ret = genpd_of_parse(genpd);
+	if (ret)
+		return ret;
+
 	if (genpd->state_idx >= GENPD_MAX_NUM_STATES) {
 		pr_warn("Initial state index out of bounds.\n");
 		genpd->state_idx = GENPD_MAX_NUM_STATES - 1;
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 31fec85..a3ac52d 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -40,6 +40,8 @@ struct gpd_dev_ops {
 struct genpd_power_state {
 	s64 power_off_latency_ns;
 	s64 power_on_latency_ns;
+	s64 residency_ns;
+	u32 param;
 };
 
 struct generic_pm_domain {
@@ -51,6 +53,7 @@ struct generic_pm_domain {
 	struct mutex lock;
 	struct dev_power_governor *gov;
 	struct work_struct power_off_work;
+	struct device_node *of_node;	/* Device node of the PM domain */
 	const char *name;
 	atomic_t sd_count;	/* Number of subdomains with power "on" */
 	enum gpd_status status;	/* Current state of the domain */
-- 
2.7.4

[PATCH 01/14] PM / Domains: Allow domain power states to be read from DT

[Lina Iyer]

From: Axel Haslam <ahaslam+renesas@baylibre.com>

This patch allows domains to define idle states in the DT. SoC's can
define domain idle states in DT using the "power-states" property of the
domain provider. Calling of_pm_genpd_init() will  read the idle states
and initialize the genpd for the domain.

In addition to the entry and exit latency for idle state, also add
residency and state-param properties. A domain idling in a state is only
power effecient if it stays idle for a certain period in that state. The
residency provides this minimum time for the idle state to provide power
benefits. The state-param is a state specific u32 value that the
platform may use for that idle state.

Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
[Lina: Added state properties, removed state names, wakeup-latency,
added of_pm_genpd_init() API, pruned commit text]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[Ulf: Moved around code to make it compile properly, rebased on top of multiple
state support,changed to use pm_genpd_init()]
---
 drivers/base/power/domain.c | 84 ++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/pm_domain.h   |  3 ++
 2 files changed, 86 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index a1f2aff..62ffabd 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1253,6 +1253,82 @@ out:
 }
 EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
 
+static int genpd_of_get_power_state(struct genpd_power_state *genpd_state,
+				    struct device_node *state_node)
+{
+	int err = 0;
+	u32 latency;
+	u32 residency;
+	u32 param;
+	u32 entry_latency, exit_latency;
+
+	err = of_property_read_u32(state_node, "entry-latency-us",
+				   &entry_latency);
+	if (err) {
+		pr_debug(" * %s missing entry-latency-us property\n",
+			 state_node->full_name);
+		return -EINVAL;
+	}
+
+	err = of_property_read_u32(state_node, "exit-latency-us",
+				   &exit_latency);
+	if (err) {
+		pr_debug(" * %s missing exit-latency-us property\n",
+			 state_node->full_name);
+		return -EINVAL;
+	}
+
+	err = of_property_read_u32(state_node, "residency-us", &residency);
+	if (!err)
+		genpd_state->residency_ns = 1000 * residency;
+
+	err = of_property_read_u32(state_node, "state-param", &param);
+	if (!err)
+		genpd_state->param = param;
+
+	latency = entry_latency + exit_latency;
+	genpd_state->power_on_latency_ns = 1000 * latency;
+	genpd_state->power_off_latency_ns = 1000 * entry_latency;
+
+	return 0;
+}
+
+static int genpd_of_parse_power_states(struct generic_pm_domain *genpd)
+{
+	struct device_node *np;
+	int i, err = 0;
+
+	for (i = 0; i < GENPD_MAX_NUM_STATES; i++) {
+		np = of_parse_phandle(genpd->of_node, "power-states", i);
+		if (!np)
+			break;
+
+		err = genpd_of_get_power_state(&genpd->states[i], np);
+		if (err) {
+			pr_err
+			    ("Parsing idle state node %s failed with err %d\n",
+			     np->full_name, err);
+			err = -EINVAL;
+			break;
+		}
+		of_node_put(np);
+	}
+
+	if (err)
+		return err;
+
+	genpd->state_count = i;
+	return 0;
+}
+
+static int genpd_of_parse(struct generic_pm_domain *genpd)
+{
+	if (!genpd->of_node)
+		return 0;
+
+	return genpd_of_parse_power_states(genpd);
+}
+
 /**
  * pm_genpd_init - Initialize a generic I/O PM domain object.
  * @genpd: PM domain object to initialize.
@@ -1262,8 +1338,10 @@ EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
  * Returns 0 on successful initialization, else a negative error code.
  */
 int pm_genpd_init(struct generic_pm_domain *genpd,
-		  struct dev_power_governor *gov, bool is_off)
+		   struct dev_power_governor *gov, bool is_off)
 {
+	int ret;
+
 	if (IS_ERR_OR_NULL(genpd))
 		return -EINVAL;
 
@@ -1306,6 +1384,10 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 		genpd->dev_ops.start = pm_clk_resume;
 	}
 
+	ret = genpd_of_parse(genpd);
+	if (ret)
+		return ret;
+
 	if (genpd->state_idx >= GENPD_MAX_NUM_STATES) {
 		pr_warn("Initial state index out of bounds.\n");
 		genpd->state_idx = GENPD_MAX_NUM_STATES - 1;
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 31fec85..a3ac52d 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -40,6 +40,8 @@ struct gpd_dev_ops {
 struct genpd_power_state {
 	s64 power_off_latency_ns;
 	s64 power_on_latency_ns;
+	s64 residency_ns;
+	u32 param;
 };
 
 struct generic_pm_domain {
@@ -51,6 +53,7 @@ struct generic_pm_domain {
 	struct mutex lock;
 	struct dev_power_governor *gov;
 	struct work_struct power_off_work;
+	struct device_node *of_node;	/* Device node of the PM domain */
 	const char *name;
 	atomic_t sd_count;	/* Number of subdomains with power "on" */
 	enum gpd_status status;	/* Current state of the domain */
-- 
2.7.4

[PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Lina Iyer]

From: Axel Haslam <ahaslam+renesas-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>

Update DT bindings to describe idle states of PM domains.

Cc: <devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Signed-off-by: Marc Titinger <mtitinger+renesas-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
Signed-off-by: Lina Iyer <lina.iyer-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
[Lina: Added state properties, removed state names, wakeup-latency,
added of_pm_genpd_init() API, pruned commit text]
Signed-off-by: Ulf Hansson <ulf.hansson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
[Ulf: Moved around code to make it compile properly, rebased on top of multiple state support]
---
 .../devicetree/bindings/power/power_domain.txt     | 70 ++++++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
index 025b5e7..41e8dda 100644
--- a/Documentation/devicetree/bindings/power/power_domain.txt
+++ b/Documentation/devicetree/bindings/power/power_domain.txt
@@ -29,6 +29,43 @@ Optional properties:
    specified by this binding. More details about power domain specifier are
    available in the next section.
 
+- power-states : A phandle of an idle-state that shall be soaked into a
+                generic domain power state.
+
+==Power state==
+
+A PM domain power state describes an idle state of a domain and must be
+have the following properties -
+
+	- entry-latency-us
+		Usage: Not required if wakeup-latency-us is provided.
+		Value type: <prop-encoded-array>
+		Definition: u32 value representing worst case latency in
+		microseconds required to enter the idle state.
+		The exit-latency-us duration may be guaranteed
+		only after entry-latency-us has passed.
+
+	- exit-latency-us
+		Usage: Not required if wakeup-latency-us is provided.
+		Value type: <prop-encoded-array>
+		Definition: u32 value representing worst case latency
+		in microseconds required to exit the idle state.
+
+	- residency-us:
+		Usage: Optional
+		Value type: <prop-encoded-array>
+		Definition: A u32 value representing the time for which a
+		domain must be idle in the state to reap power saving benefits
+		of entering the state.
+
+	- state-param:
+		Usage: Optional
+		Value type: <prop-encoded-array>
+		Definition: A u32 value as defined by the state. May be used
+		by the driver to hold state related u32 data. In the case of
+		PSCI, an extended state-id for the domain may be encoded in
+		this value.
+
 Example:
 
 	power: power-controller@12340000 {
@@ -55,6 +92,39 @@ Example 2:
 		#power-domain-cells = <1>;
 	};
 
+Example 3:
+
+	pm-domains {
+		a57_pd: a57_pd@ {
+			/* will have a57 platform ARM_PD_METHOD_OF_DECLARE*/
+			compatible = "arm,pd","arm,cortex-a57";
+			#power-domain-cells = <0>;
+			power-states = <&CLUSTER_SLEEP_0>;
+		};
+
+		a53_pd: a53_pd@ {
+			/* will have a a53 platform ARM_PD_METHOD_OF_DECLARE*/
+			compatible = "arm,pd","arm,cortex-a53";
+			#power-domain-cells = <0>;
+			power-states = <&CLUSTER_SLEEP_0>, <&CLUSTER_SLEEP_1>;
+		};
+
+		CLUSTER_SLEEP_0: power-state@0 {
+			entry-latency-us = <1000>;
+			exit-latency-us = <2000>;
+			residency-us = <10000>;
+			state-param = <0x1000010>;
+		};
+
+		CLUSTER_SLEEP_1: power-state@1 {
+			entry-latency-us = <5000>;
+			exit-latency-us = <5000>;
+			residency-us = <100000>;
+			state-param = <0x1000020>;
+		};
+	};
+
+
 The nodes above define two power controllers: 'parent' and 'child'.
 Domains created by the 'child' power controller are subdomains of '0' power
 domain provided by the 'parent' power controller.
-- 
2.7.4

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[PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Lina Iyer]

From: Axel Haslam <ahaslam+renesas@baylibre.com>

Update DT bindings to describe idle states of PM domains.

Cc: <devicetree@vger.kernel.org>
Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
[Lina: Added state properties, removed state names, wakeup-latency,
added of_pm_genpd_init() API, pruned commit text]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[Ulf: Moved around code to make it compile properly, rebased on top of multiple state support]
---
 .../devicetree/bindings/power/power_domain.txt     | 70 ++++++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
index 025b5e7..41e8dda 100644
--- a/Documentation/devicetree/bindings/power/power_domain.txt
+++ b/Documentation/devicetree/bindings/power/power_domain.txt
@@ -29,6 +29,43 @@ Optional properties:
    specified by this binding. More details about power domain specifier are
    available in the next section.
 
+- power-states : A phandle of an idle-state that shall be soaked into a
+                generic domain power state.
+
+==Power state==
+
+A PM domain power state describes an idle state of a domain and must be
+have the following properties -
+
+	- entry-latency-us
+		Usage: Not required if wakeup-latency-us is provided.
+		Value type: <prop-encoded-array>
+		Definition: u32 value representing worst case latency in
+		microseconds required to enter the idle state.
+		The exit-latency-us duration may be guaranteed
+		only after entry-latency-us has passed.
+
+	- exit-latency-us
+		Usage: Not required if wakeup-latency-us is provided.
+		Value type: <prop-encoded-array>
+		Definition: u32 value representing worst case latency
+		in microseconds required to exit the idle state.
+
+	- residency-us:
+		Usage: Optional
+		Value type: <prop-encoded-array>
+		Definition: A u32 value representing the time for which a
+		domain must be idle in the state to reap power saving benefits
+		of entering the state.
+
+	- state-param:
+		Usage: Optional
+		Value type: <prop-encoded-array>
+		Definition: A u32 value as defined by the state. May be used
+		by the driver to hold state related u32 data. In the case of
+		PSCI, an extended state-id for the domain may be encoded in
+		this value.
+
 Example:
 
 	power: power-controller at 12340000 {
@@ -55,6 +92,39 @@ Example 2:
 		#power-domain-cells = <1>;
 	};
 
+Example 3:
+
+	pm-domains {
+		a57_pd: a57_pd@ {
+			/* will have a57 platform ARM_PD_METHOD_OF_DECLARE*/
+			compatible = "arm,pd","arm,cortex-a57";
+			#power-domain-cells = <0>;
+			power-states = <&CLUSTER_SLEEP_0>;
+		};
+
+		a53_pd: a53_pd@ {
+			/* will have a a53 platform ARM_PD_METHOD_OF_DECLARE*/
+			compatible = "arm,pd","arm,cortex-a53";
+			#power-domain-cells = <0>;
+			power-states = <&CLUSTER_SLEEP_0>, <&CLUSTER_SLEEP_1>;
+		};
+
+		CLUSTER_SLEEP_0: power-state at 0 {
+			entry-latency-us = <1000>;
+			exit-latency-us = <2000>;
+			residency-us = <10000>;
+			state-param = <0x1000010>;
+		};
+
+		CLUSTER_SLEEP_1: power-state at 1 {
+			entry-latency-us = <5000>;
+			exit-latency-us = <5000>;
+			residency-us = <100000>;
+			state-param = <0x1000020>;
+		};
+	};
+
+
 The nodes above define two power controllers: 'parent' and 'child'.
 Domains created by the 'child' power controller are subdomains of '0' power
 domain provided by the 'parent' power controller.
-- 
2.7.4

[PATCH 03/14] PM / Domains: Abstract genpd locking

[Lina Iyer]

Abstract genpd lock/unlock calls, in preparation for domain specific
locks added in the following patches.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Krzysztof Kozłowski <k.kozlowski@samsung.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
[Ulf: Rebased as additional mutex_lock|unlock has been added]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/base/power/domain.c | 113 ++++++++++++++++++++++++++++++--------------
 include/linux/pm_domain.h   |   5 +-
 2 files changed, 81 insertions(+), 37 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 62ffabd..8d41e4c 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -39,6 +39,46 @@
 static LIST_HEAD(gpd_list);
 static DEFINE_MUTEX(gpd_list_lock);
 
+struct genpd_lock_fns {
+	void (*lock)(struct generic_pm_domain *genpd);
+	void (*lock_nested)(struct generic_pm_domain *genpd, int depth);
+	int (*lock_interruptible)(struct generic_pm_domain *genpd);
+	void (*unlock)(struct generic_pm_domain *genpd);
+};
+
+static void genpd_lock_mtx(struct generic_pm_domain *genpd)
+{
+	mutex_lock(&genpd->mlock);
+}
+
+static void genpd_lock_nested_mtx(struct generic_pm_domain *genpd,
+					int depth)
+{
+	mutex_lock_nested(&genpd->mlock, depth);
+}
+
+static int genpd_lock_interruptible_mtx(struct generic_pm_domain *genpd)
+{
+	return mutex_lock_interruptible(&genpd->mlock);
+}
+
+static void genpd_unlock_mtx(struct generic_pm_domain *genpd)
+{
+	return mutex_unlock(&genpd->mlock);
+}
+
+static const struct genpd_lock_fns genpd_mtx_fns  = {
+	.lock = genpd_lock_mtx,
+	.lock_nested = genpd_lock_nested_mtx,
+	.lock_interruptible = genpd_lock_interruptible_mtx,
+	.unlock = genpd_unlock_mtx,
+};
+
+#define genpd_lock(p)			p->lock_fns->lock(p)
+#define genpd_lock_nested(p, d)		p->lock_fns->lock_nested(p, d)
+#define genpd_lock_interruptible(p)	p->lock_fns->lock_interruptible(p)
+#define genpd_unlock(p)			p->lock_fns->unlock(p)
+
 /*
  * Get the generic PM domain for a particular struct device.
  * This validates the struct device pointer, the PM domain pointer,
@@ -200,9 +240,9 @@ static int genpd_poweron(struct generic_pm_domain *genpd, unsigned int depth)
 
 		genpd_sd_counter_inc(master);
 
-		mutex_lock_nested(&master->lock, depth + 1);
+		genpd_lock_nested(master, depth + 1);
 		ret = genpd_poweron(master, depth + 1);
-		mutex_unlock(&master->lock);
+		genpd_unlock(master);
 
 		if (ret) {
 			genpd_sd_counter_dec(master);
@@ -255,9 +295,9 @@ static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
 		spin_unlock_irq(&dev->power.lock);
 
 		if (!IS_ERR(genpd)) {
-			mutex_lock(&genpd->lock);
+			genpd_lock(genpd);
 			genpd->max_off_time_changed = true;
-			mutex_unlock(&genpd->lock);
+			genpd_unlock(genpd);
 		}
 
 		dev = dev->parent;
@@ -354,9 +394,9 @@ static void genpd_power_off_work_fn(struct work_struct *work)
 
 	genpd = container_of(work, struct generic_pm_domain, power_off_work);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 	genpd_poweroff(genpd, true);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 }
 
 /**
@@ -472,9 +512,9 @@ static int genpd_runtime_suspend(struct device *dev)
 	if (dev->power.irq_safe)
 		return 0;
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 	genpd_poweroff(genpd, false);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	return 0;
 }
@@ -509,9 +549,9 @@ static int genpd_runtime_resume(struct device *dev)
 		goto out;
 	}
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 	ret = genpd_poweron(genpd, 0);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	if (ret)
 		return ret;
@@ -547,9 +587,9 @@ err_stop:
 	genpd_stop_dev(genpd, dev);
 err_poweroff:
 	if (!dev->power.irq_safe) {
-		mutex_lock(&genpd->lock);
+		genpd_lock(genpd);
 		genpd_poweroff(genpd, 0);
-		mutex_unlock(&genpd->lock);
+		genpd_unlock(genpd);
 	}
 
 	return ret;
@@ -732,20 +772,20 @@ static int pm_genpd_prepare(struct device *dev)
 	if (resume_needed(dev, genpd))
 		pm_runtime_resume(dev);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	if (genpd->prepared_count++ == 0)
 		genpd->suspended_count = 0;
 
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	ret = pm_generic_prepare(dev);
 	if (ret) {
-		mutex_lock(&genpd->lock);
+		genpd_lock(genpd);
 
 		genpd->prepared_count--;
 
-		mutex_unlock(&genpd->lock);
+		genpd_unlock(genpd);
 	}
 
 	return ret;
@@ -936,13 +976,13 @@ static void pm_genpd_complete(struct device *dev)
 
 	pm_generic_complete(dev);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	genpd->prepared_count--;
 	if (!genpd->prepared_count)
 		genpd_queue_power_off_work(genpd);
 
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 }
 
 /**
@@ -1077,7 +1117,7 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	if (IS_ERR(gpd_data))
 		return PTR_ERR(gpd_data);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	if (genpd->prepared_count > 0) {
 		ret = -EAGAIN;
@@ -1094,7 +1134,7 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	list_add_tail(&gpd_data->base.list_node, &genpd->dev_list);
 
  out:
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	if (ret)
 		genpd_free_dev_data(dev, gpd_data);
@@ -1127,7 +1167,7 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 	gpd_data = to_gpd_data(pdd);
 	dev_pm_qos_remove_notifier(dev, &gpd_data->nb);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	if (genpd->prepared_count > 0) {
 		ret = -EAGAIN;
@@ -1142,14 +1182,14 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 
 	list_del_init(&pdd->list_node);
 
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	genpd_free_dev_data(dev, gpd_data);
 
 	return 0;
 
  out:
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 	dev_pm_qos_add_notifier(dev, &gpd_data->nb);
 
 	return ret;
@@ -1175,8 +1215,8 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
 	if (!link)
 		return -ENOMEM;
 
-	mutex_lock(&subdomain->lock);
-	mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
+	genpd_lock(subdomain);
+	genpd_lock_nested(genpd, SINGLE_DEPTH_NESTING);
 
 	if (genpd->status == GPD_STATE_POWER_OFF
 	    &&  subdomain->status != GPD_STATE_POWER_OFF) {
@@ -1199,8 +1239,8 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
 		genpd_sd_counter_inc(genpd);
 
  out:
-	mutex_unlock(&genpd->lock);
-	mutex_unlock(&subdomain->lock);
+	genpd_unlock(genpd);
+	genpd_unlock(subdomain);
 	if (ret)
 		kfree(link);
 	return ret;
@@ -1221,8 +1261,8 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 	if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(subdomain))
 		return -EINVAL;
 
-	mutex_lock(&subdomain->lock);
-	mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
+	genpd_lock(subdomain);
+	genpd_lock_nested(genpd, SINGLE_DEPTH_NESTING);
 
 	if (!list_empty(&subdomain->master_links) || subdomain->device_count) {
 		pr_warn("%s: unable to remove subdomain %s\n", genpd->name,
@@ -1246,8 +1286,8 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 	}
 
 out:
-	mutex_unlock(&genpd->lock);
-	mutex_unlock(&subdomain->lock);
+	genpd_unlock(genpd);
+	genpd_unlock(subdomain);
 
 	return ret;
 }
@@ -1348,7 +1388,8 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 	INIT_LIST_HEAD(&genpd->master_links);
 	INIT_LIST_HEAD(&genpd->slave_links);
 	INIT_LIST_HEAD(&genpd->dev_list);
-	mutex_init(&genpd->lock);
+	mutex_init(&genpd->mlock);
+	genpd->lock_fns = &genpd_mtx_fns;
 	genpd->gov = gov;
 	INIT_WORK(&genpd->power_off_work, genpd_power_off_work_fn);
 	atomic_set(&genpd->sd_count, 0);
@@ -1706,9 +1747,9 @@ int genpd_dev_pm_attach(struct device *dev)
 	dev->pm_domain->detach = genpd_dev_pm_detach;
 	dev->pm_domain->sync = genpd_dev_pm_sync;
 
-	mutex_lock(&pd->lock);
+	genpd_lock(pd);
 	ret = genpd_poweron(pd, 0);
-	mutex_unlock(&pd->lock);
+	genpd_unlock(pd);
 out:
 	return ret ? -EPROBE_DEFER : 0;
 }
@@ -1766,7 +1807,7 @@ static int pm_genpd_summary_one(struct seq_file *s,
 	char state[16];
 	int ret;
 
-	ret = mutex_lock_interruptible(&genpd->lock);
+	ret = genpd_lock_interruptible(genpd);
 	if (ret)
 		return -ERESTARTSYS;
 
@@ -1803,7 +1844,7 @@ static int pm_genpd_summary_one(struct seq_file *s,
 
 	seq_puts(s, "\n");
 exit:
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	return 0;
 }
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index a3ac52d..2d7e1bc 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -44,13 +44,14 @@ struct genpd_power_state {
 	u32 param;
 };
 
+struct genpd_lock_fns;
+
 struct generic_pm_domain {
 	struct dev_pm_domain domain;	/* PM domain operations */
 	struct list_head gpd_list_node;	/* Node in the global PM domains list */
 	struct list_head master_links;	/* Links with PM domain as a master */
 	struct list_head slave_links;	/* Links with PM domain as a slave */
 	struct list_head dev_list;	/* List of devices */
-	struct mutex lock;
 	struct dev_power_governor *gov;
 	struct work_struct power_off_work;
 	struct device_node *of_node;	/* Device node of the PM domain */
@@ -74,6 +75,8 @@ struct generic_pm_domain {
 	struct genpd_power_state states[GENPD_MAX_NUM_STATES];
 	unsigned int state_count; /* number of states */
 	unsigned int state_idx; /* state that genpd will go to when off */
+	const struct genpd_lock_fns *lock_fns;
+	struct mutex mlock;
 
 };
 
-- 
2.7.4

[PATCH 03/14] PM / Domains: Abstract genpd locking

[Lina Iyer]

Abstract genpd lock/unlock calls, in preparation for domain specific
locks added in the following patches.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Krzysztof Koz?owski <k.kozlowski@samsung.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
[Ulf: Rebased as additional mutex_lock|unlock has been added]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/base/power/domain.c | 113 ++++++++++++++++++++++++++++++--------------
 include/linux/pm_domain.h   |   5 +-
 2 files changed, 81 insertions(+), 37 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 62ffabd..8d41e4c 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -39,6 +39,46 @@
 static LIST_HEAD(gpd_list);
 static DEFINE_MUTEX(gpd_list_lock);
 
+struct genpd_lock_fns {
+	void (*lock)(struct generic_pm_domain *genpd);
+	void (*lock_nested)(struct generic_pm_domain *genpd, int depth);
+	int (*lock_interruptible)(struct generic_pm_domain *genpd);
+	void (*unlock)(struct generic_pm_domain *genpd);
+};
+
+static void genpd_lock_mtx(struct generic_pm_domain *genpd)
+{
+	mutex_lock(&genpd->mlock);
+}
+
+static void genpd_lock_nested_mtx(struct generic_pm_domain *genpd,
+					int depth)
+{
+	mutex_lock_nested(&genpd->mlock, depth);
+}
+
+static int genpd_lock_interruptible_mtx(struct generic_pm_domain *genpd)
+{
+	return mutex_lock_interruptible(&genpd->mlock);
+}
+
+static void genpd_unlock_mtx(struct generic_pm_domain *genpd)
+{
+	return mutex_unlock(&genpd->mlock);
+}
+
+static const struct genpd_lock_fns genpd_mtx_fns  = {
+	.lock = genpd_lock_mtx,
+	.lock_nested = genpd_lock_nested_mtx,
+	.lock_interruptible = genpd_lock_interruptible_mtx,
+	.unlock = genpd_unlock_mtx,
+};
+
+#define genpd_lock(p)			p->lock_fns->lock(p)
+#define genpd_lock_nested(p, d)		p->lock_fns->lock_nested(p, d)
+#define genpd_lock_interruptible(p)	p->lock_fns->lock_interruptible(p)
+#define genpd_unlock(p)			p->lock_fns->unlock(p)
+
 /*
  * Get the generic PM domain for a particular struct device.
  * This validates the struct device pointer, the PM domain pointer,
@@ -200,9 +240,9 @@ static int genpd_poweron(struct generic_pm_domain *genpd, unsigned int depth)
 
 		genpd_sd_counter_inc(master);
 
-		mutex_lock_nested(&master->lock, depth + 1);
+		genpd_lock_nested(master, depth + 1);
 		ret = genpd_poweron(master, depth + 1);
-		mutex_unlock(&master->lock);
+		genpd_unlock(master);
 
 		if (ret) {
 			genpd_sd_counter_dec(master);
@@ -255,9 +295,9 @@ static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
 		spin_unlock_irq(&dev->power.lock);
 
 		if (!IS_ERR(genpd)) {
-			mutex_lock(&genpd->lock);
+			genpd_lock(genpd);
 			genpd->max_off_time_changed = true;
-			mutex_unlock(&genpd->lock);
+			genpd_unlock(genpd);
 		}
 
 		dev = dev->parent;
@@ -354,9 +394,9 @@ static void genpd_power_off_work_fn(struct work_struct *work)
 
 	genpd = container_of(work, struct generic_pm_domain, power_off_work);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 	genpd_poweroff(genpd, true);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 }
 
 /**
@@ -472,9 +512,9 @@ static int genpd_runtime_suspend(struct device *dev)
 	if (dev->power.irq_safe)
 		return 0;
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 	genpd_poweroff(genpd, false);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	return 0;
 }
@@ -509,9 +549,9 @@ static int genpd_runtime_resume(struct device *dev)
 		goto out;
 	}
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 	ret = genpd_poweron(genpd, 0);
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	if (ret)
 		return ret;
@@ -547,9 +587,9 @@ err_stop:
 	genpd_stop_dev(genpd, dev);
 err_poweroff:
 	if (!dev->power.irq_safe) {
-		mutex_lock(&genpd->lock);
+		genpd_lock(genpd);
 		genpd_poweroff(genpd, 0);
-		mutex_unlock(&genpd->lock);
+		genpd_unlock(genpd);
 	}
 
 	return ret;
@@ -732,20 +772,20 @@ static int pm_genpd_prepare(struct device *dev)
 	if (resume_needed(dev, genpd))
 		pm_runtime_resume(dev);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	if (genpd->prepared_count++ == 0)
 		genpd->suspended_count = 0;
 
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	ret = pm_generic_prepare(dev);
 	if (ret) {
-		mutex_lock(&genpd->lock);
+		genpd_lock(genpd);
 
 		genpd->prepared_count--;
 
-		mutex_unlock(&genpd->lock);
+		genpd_unlock(genpd);
 	}
 
 	return ret;
@@ -936,13 +976,13 @@ static void pm_genpd_complete(struct device *dev)
 
 	pm_generic_complete(dev);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	genpd->prepared_count--;
 	if (!genpd->prepared_count)
 		genpd_queue_power_off_work(genpd);
 
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 }
 
 /**
@@ -1077,7 +1117,7 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	if (IS_ERR(gpd_data))
 		return PTR_ERR(gpd_data);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	if (genpd->prepared_count > 0) {
 		ret = -EAGAIN;
@@ -1094,7 +1134,7 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	list_add_tail(&gpd_data->base.list_node, &genpd->dev_list);
 
  out:
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	if (ret)
 		genpd_free_dev_data(dev, gpd_data);
@@ -1127,7 +1167,7 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 	gpd_data = to_gpd_data(pdd);
 	dev_pm_qos_remove_notifier(dev, &gpd_data->nb);
 
-	mutex_lock(&genpd->lock);
+	genpd_lock(genpd);
 
 	if (genpd->prepared_count > 0) {
 		ret = -EAGAIN;
@@ -1142,14 +1182,14 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd,
 
 	list_del_init(&pdd->list_node);
 
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	genpd_free_dev_data(dev, gpd_data);
 
 	return 0;
 
  out:
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 	dev_pm_qos_add_notifier(dev, &gpd_data->nb);
 
 	return ret;
@@ -1175,8 +1215,8 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
 	if (!link)
 		return -ENOMEM;
 
-	mutex_lock(&subdomain->lock);
-	mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
+	genpd_lock(subdomain);
+	genpd_lock_nested(genpd, SINGLE_DEPTH_NESTING);
 
 	if (genpd->status == GPD_STATE_POWER_OFF
 	    &&  subdomain->status != GPD_STATE_POWER_OFF) {
@@ -1199,8 +1239,8 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
 		genpd_sd_counter_inc(genpd);
 
  out:
-	mutex_unlock(&genpd->lock);
-	mutex_unlock(&subdomain->lock);
+	genpd_unlock(genpd);
+	genpd_unlock(subdomain);
 	if (ret)
 		kfree(link);
 	return ret;
@@ -1221,8 +1261,8 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 	if (IS_ERR_OR_NULL(genpd) || IS_ERR_OR_NULL(subdomain))
 		return -EINVAL;
 
-	mutex_lock(&subdomain->lock);
-	mutex_lock_nested(&genpd->lock, SINGLE_DEPTH_NESTING);
+	genpd_lock(subdomain);
+	genpd_lock_nested(genpd, SINGLE_DEPTH_NESTING);
 
 	if (!list_empty(&subdomain->master_links) || subdomain->device_count) {
 		pr_warn("%s: unable to remove subdomain %s\n", genpd->name,
@@ -1246,8 +1286,8 @@ int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
 	}
 
 out:
-	mutex_unlock(&genpd->lock);
-	mutex_unlock(&subdomain->lock);
+	genpd_unlock(genpd);
+	genpd_unlock(subdomain);
 
 	return ret;
 }
@@ -1348,7 +1388,8 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 	INIT_LIST_HEAD(&genpd->master_links);
 	INIT_LIST_HEAD(&genpd->slave_links);
 	INIT_LIST_HEAD(&genpd->dev_list);
-	mutex_init(&genpd->lock);
+	mutex_init(&genpd->mlock);
+	genpd->lock_fns = &genpd_mtx_fns;
 	genpd->gov = gov;
 	INIT_WORK(&genpd->power_off_work, genpd_power_off_work_fn);
 	atomic_set(&genpd->sd_count, 0);
@@ -1706,9 +1747,9 @@ int genpd_dev_pm_attach(struct device *dev)
 	dev->pm_domain->detach = genpd_dev_pm_detach;
 	dev->pm_domain->sync = genpd_dev_pm_sync;
 
-	mutex_lock(&pd->lock);
+	genpd_lock(pd);
 	ret = genpd_poweron(pd, 0);
-	mutex_unlock(&pd->lock);
+	genpd_unlock(pd);
 out:
 	return ret ? -EPROBE_DEFER : 0;
 }
@@ -1766,7 +1807,7 @@ static int pm_genpd_summary_one(struct seq_file *s,
 	char state[16];
 	int ret;
 
-	ret = mutex_lock_interruptible(&genpd->lock);
+	ret = genpd_lock_interruptible(genpd);
 	if (ret)
 		return -ERESTARTSYS;
 
@@ -1803,7 +1844,7 @@ static int pm_genpd_summary_one(struct seq_file *s,
 
 	seq_puts(s, "\n");
 exit:
-	mutex_unlock(&genpd->lock);
+	genpd_unlock(genpd);
 
 	return 0;
 }
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index a3ac52d..2d7e1bc 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -44,13 +44,14 @@ struct genpd_power_state {
 	u32 param;
 };
 
+struct genpd_lock_fns;
+
 struct generic_pm_domain {
 	struct dev_pm_domain domain;	/* PM domain operations */
 	struct list_head gpd_list_node;	/* Node in the global PM domains list */
 	struct list_head master_links;	/* Links with PM domain as a master */
 	struct list_head slave_links;	/* Links with PM domain as a slave */
 	struct list_head dev_list;	/* List of devices */
-	struct mutex lock;
 	struct dev_power_governor *gov;
 	struct work_struct power_off_work;
 	struct device_node *of_node;	/* Device node of the PM domain */
@@ -74,6 +75,8 @@ struct generic_pm_domain {
 	struct genpd_power_state states[GENPD_MAX_NUM_STATES];
 	unsigned int state_count; /* number of states */
 	unsigned int state_idx; /* state that genpd will go to when off */
+	const struct genpd_lock_fns *lock_fns;
+	struct mutex mlock;
 
 };
 
-- 
2.7.4

[PATCH 04/14] PM / Domains: Support IRQ safe PM domains

[Lina Iyer]

Generic Power Domains currently support turning on/off only in process
context. This prevents the usage of PM domains for domains that could be
powered on/off in a context where IRQs are disabled. Many such domains
exist today and do not get powered off, when the IRQ safe devices in
that domain are powered off, because of this limitation.

However, not all domains can operate in IRQ safe contexts. Genpd
therefore, has to support both cases where the domain may or may not
operate in IRQ safe contexts. Configuring genpd to use an appropriate
lock for that domain, would allow domains that have IRQ safe devices to
runtime suspend and resume, in atomic context.

To achieve domain specific locking, set the domain's ->flag to
GENPD_FLAG_IRQ_SAFE while defining the domain. This indicates that genpd
should use a spinlock instead of a mutex for locking the domain. Locking
is abstracted through genpd_lock() and genpd_unlock() functions that use
the flag to determine the appropriate lock to be used for that domain.

Domains that have lower latency to suspend and resume and can operate
with IRQs disabled may now be able to save power, when the component
devices and sub-domains are idle at runtime.

The restriction this imposes on the domain hierarchy is that non-IRQ
safe domains may not have IRQ-safe subdomains, but IRQ safe domains may
have IRQ safe and non-IRQ safe subdomains and devices.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Krzysztof Kozłowski <k.kozlowski@samsung.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
[Ulf: Rebased and solved a conflict]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/base/power/domain.c | 107 +++++++++++++++++++++++++++++++++++++++-----
 include/linux/pm_domain.h   |  10 ++++-
 2 files changed, 106 insertions(+), 11 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 8d41e4c..b1c2aa6 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -74,11 +74,61 @@ static const struct genpd_lock_fns genpd_mtx_fns  = {
 	.unlock = genpd_unlock_mtx,
 };
 
+static void genpd_lock_spin(struct generic_pm_domain *genpd)
+	__acquires(&genpd->slock)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&genpd->slock, flags);
+	genpd->lock_flags = flags;
+}
+
+static void genpd_lock_nested_spin(struct generic_pm_domain *genpd,
+					int depth)
+	__acquires(&genpd->slock)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave_nested(&genpd->slock, flags, depth);
+	genpd->lock_flags = flags;
+}
+
+static int genpd_lock_interruptible_spin(struct generic_pm_domain *genpd)
+	__acquires(&genpd->slock)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&genpd->slock, flags);
+	genpd->lock_flags = flags;
+	return 0;
+}
+
+static void genpd_unlock_spin(struct generic_pm_domain *genpd)
+	__releases(&genpd->slock)
+{
+	spin_unlock_irqrestore(&genpd->slock, genpd->lock_flags);
+}
+
+static const struct genpd_lock_fns genpd_spin_fns = {
+	.lock = genpd_lock_spin,
+	.lock_nested = genpd_lock_nested_spin,
+	.lock_interruptible = genpd_lock_interruptible_spin,
+	.unlock = genpd_unlock_spin,
+};
+
 #define genpd_lock(p)			p->lock_fns->lock(p)
 #define genpd_lock_nested(p, d)		p->lock_fns->lock_nested(p, d)
 #define genpd_lock_interruptible(p)	p->lock_fns->lock_interruptible(p)
 #define genpd_unlock(p)			p->lock_fns->unlock(p)
 
+#define genpd_is_irq_safe(genpd)	(genpd->flags & GENPD_FLAG_IRQ_SAFE)
+
+static inline bool irq_safe_dev_in_no_sleep_domain(struct device *dev,
+		struct generic_pm_domain *genpd)
+{
+	return pm_runtime_is_irq_safe(dev) && !genpd_is_irq_safe(genpd);
+}
+
 /*
  * Get the generic PM domain for a particular struct device.
  * This validates the struct device pointer, the PM domain pointer,
@@ -343,7 +393,12 @@ static int genpd_poweroff(struct generic_pm_domain *genpd, bool is_async)
 		if (stat > PM_QOS_FLAGS_NONE)
 			return -EBUSY;
 
-		if (!pm_runtime_suspended(pdd->dev) || pdd->dev->power.irq_safe)
+		/*
+		 * Do not allow PM domain to be powered off, when an IRQ safe
+		 * device is part of a non-IRQ safe domain.
+		 */
+		if (!pm_runtime_suspended(pdd->dev) ||
+			irq_safe_dev_in_no_sleep_domain(pdd->dev, genpd))
 			not_suspended++;
 	}
 
@@ -506,10 +561,10 @@ static int genpd_runtime_suspend(struct device *dev)
 	}
 
 	/*
-	 * If power.irq_safe is set, this routine will be run with interrupts
-	 * off, so it can't use mutexes.
+	 * If power.irq_safe is set, this routine may be run with
+	 * IRQs disabled, so suspend only if the PM domain also is irq_safe.
 	 */
-	if (dev->power.irq_safe)
+	if (irq_safe_dev_in_no_sleep_domain(dev, genpd))
 		return 0;
 
 	genpd_lock(genpd);
@@ -543,8 +598,11 @@ static int genpd_runtime_resume(struct device *dev)
 	if (IS_ERR(genpd))
 		return -EINVAL;
 
-	/* If power.irq_safe, the PM domain is never powered off. */
-	if (dev->power.irq_safe) {
+	/*
+	 * As we don't power off a non IRQ safe domain, which holds
+	 * an IRQ safe device, we don't need to restore power to it.
+	 */
+	if (irq_safe_dev_in_no_sleep_domain(dev, genpd)) {
 		timed = false;
 		goto out;
 	}
@@ -586,7 +644,8 @@ static int genpd_runtime_resume(struct device *dev)
 err_stop:
 	genpd_stop_dev(genpd, dev);
 err_poweroff:
-	if (!dev->power.irq_safe) {
+	if (!dev->power.irq_safe ||
+		(dev->power.irq_safe && genpd_is_irq_safe(genpd))) {
 		genpd_lock(genpd);
 		genpd_poweroff(genpd, 0);
 		genpd_unlock(genpd);
@@ -1117,6 +1176,11 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	if (IS_ERR(gpd_data))
 		return PTR_ERR(gpd_data);
 
+	/* Check if we are adding an IRQ safe device to non-IRQ safe domain */
+	if (irq_safe_dev_in_no_sleep_domain(dev, genpd))
+		dev_warn_once(dev, "PM domain %s will not be powered off\n",
+				genpd->name);
+
 	genpd_lock(genpd);
 
 	if (genpd->prepared_count > 0) {
@@ -1211,6 +1275,17 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
 	    || genpd == subdomain)
 		return -EINVAL;
 
+	/*
+	 * If the domain can be powered on/off in an IRQ safe
+	 * context, ensure that the subdomain can also be
+	 * powered on/off in that context.
+	 */
+	if (!genpd_is_irq_safe(genpd) && genpd_is_irq_safe(subdomain)) {
+		WARN("Parent %s of subdomain %s must be IRQ safe\n",
+				genpd->name, subdomain->name);
+		return -EINVAL;
+	}
+
 	link = kzalloc(sizeof(*link), GFP_KERNEL);
 	if (!link)
 		return -ENOMEM;
@@ -1369,6 +1444,17 @@ static int genpd_of_parse(struct generic_pm_domain *genpd)
 	return genpd_of_parse_power_states(genpd);
 }
 
+static void genpd_lock_init(struct generic_pm_domain *genpd)
+{
+	if (genpd->flags & GENPD_FLAG_IRQ_SAFE) {
+		spin_lock_init(&genpd->slock);
+		genpd->lock_fns = &genpd_spin_fns;
+	} else {
+		mutex_init(&genpd->mlock);
+		genpd->lock_fns = &genpd_mtx_fns;
+	}
+}
+
 /**
  * pm_genpd_init - Initialize a generic I/O PM domain object.
  * @genpd: PM domain object to initialize.
@@ -1388,8 +1474,7 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 	INIT_LIST_HEAD(&genpd->master_links);
 	INIT_LIST_HEAD(&genpd->slave_links);
 	INIT_LIST_HEAD(&genpd->dev_list);
-	mutex_init(&genpd->mlock);
-	genpd->lock_fns = &genpd_mtx_fns;
+	genpd_lock_init(genpd);
 	genpd->gov = gov;
 	INIT_WORK(&genpd->power_off_work, genpd_power_off_work_fn);
 	atomic_set(&genpd->sd_count, 0);
@@ -1833,7 +1918,9 @@ static int pm_genpd_summary_one(struct seq_file *s,
 	}
 
 	list_for_each_entry(pm_data, &genpd->dev_list, list_node) {
-		kobj_path = kobject_get_path(&pm_data->dev->kobj, GFP_KERNEL);
+		kobj_path = kobject_get_path(&pm_data->dev->kobj,
+				genpd_is_irq_safe(genpd) ?
+				GFP_ATOMIC : GFP_KERNEL);
 		if (kobj_path == NULL)
 			continue;
 
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 2d7e1bc..9b65c79 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -15,9 +15,11 @@
 #include <linux/err.h>
 #include <linux/of.h>
 #include <linux/notifier.h>
+#include <linux/spinlock.h>
 
 /* Defines used for the flags field in the struct generic_pm_domain */
 #define GENPD_FLAG_PM_CLK	(1U << 0) /* PM domain uses PM clk */
+#define GENPD_FLAG_IRQ_SAFE	(1U << 1) /* PM domain operates in atomic */
 
 #define GENPD_MAX_NUM_STATES	8 /* Number of possible low power states */
 
@@ -76,7 +78,13 @@ struct generic_pm_domain {
 	unsigned int state_count; /* number of states */
 	unsigned int state_idx; /* state that genpd will go to when off */
 	const struct genpd_lock_fns *lock_fns;
-	struct mutex mlock;
+	union {
+		struct mutex mlock;
+		struct {
+			spinlock_t slock;
+			unsigned long lock_flags;
+		};
+	};
 
 };
 
-- 
2.7.4

[PATCH 04/14] PM / Domains: Support IRQ safe PM domains

[Lina Iyer]

Generic Power Domains currently support turning on/off only in process
context. This prevents the usage of PM domains for domains that could be
powered on/off in a context where IRQs are disabled. Many such domains
exist today and do not get powered off, when the IRQ safe devices in
that domain are powered off, because of this limitation.

However, not all domains can operate in IRQ safe contexts. Genpd
therefore, has to support both cases where the domain may or may not
operate in IRQ safe contexts. Configuring genpd to use an appropriate
lock for that domain, would allow domains that have IRQ safe devices to
runtime suspend and resume, in atomic context.

To achieve domain specific locking, set the domain's ->flag to
GENPD_FLAG_IRQ_SAFE while defining the domain. This indicates that genpd
should use a spinlock instead of a mutex for locking the domain. Locking
is abstracted through genpd_lock() and genpd_unlock() functions that use
the flag to determine the appropriate lock to be used for that domain.

Domains that have lower latency to suspend and resume and can operate
with IRQs disabled may now be able to save power, when the component
devices and sub-domains are idle at runtime.

The restriction this imposes on the domain hierarchy is that non-IRQ
safe domains may not have IRQ-safe subdomains, but IRQ safe domains may
have IRQ safe and non-IRQ safe subdomains and devices.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Krzysztof Koz?owski <k.kozlowski@samsung.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
[Ulf: Rebased and solved a conflict]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/base/power/domain.c | 107 +++++++++++++++++++++++++++++++++++++++-----
 include/linux/pm_domain.h   |  10 ++++-
 2 files changed, 106 insertions(+), 11 deletions(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 8d41e4c..b1c2aa6 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -74,11 +74,61 @@ static const struct genpd_lock_fns genpd_mtx_fns  = {
 	.unlock = genpd_unlock_mtx,
 };
 
+static void genpd_lock_spin(struct generic_pm_domain *genpd)
+	__acquires(&genpd->slock)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&genpd->slock, flags);
+	genpd->lock_flags = flags;
+}
+
+static void genpd_lock_nested_spin(struct generic_pm_domain *genpd,
+					int depth)
+	__acquires(&genpd->slock)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave_nested(&genpd->slock, flags, depth);
+	genpd->lock_flags = flags;
+}
+
+static int genpd_lock_interruptible_spin(struct generic_pm_domain *genpd)
+	__acquires(&genpd->slock)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&genpd->slock, flags);
+	genpd->lock_flags = flags;
+	return 0;
+}
+
+static void genpd_unlock_spin(struct generic_pm_domain *genpd)
+	__releases(&genpd->slock)
+{
+	spin_unlock_irqrestore(&genpd->slock, genpd->lock_flags);
+}
+
+static const struct genpd_lock_fns genpd_spin_fns = {
+	.lock = genpd_lock_spin,
+	.lock_nested = genpd_lock_nested_spin,
+	.lock_interruptible = genpd_lock_interruptible_spin,
+	.unlock = genpd_unlock_spin,
+};
+
 #define genpd_lock(p)			p->lock_fns->lock(p)
 #define genpd_lock_nested(p, d)		p->lock_fns->lock_nested(p, d)
 #define genpd_lock_interruptible(p)	p->lock_fns->lock_interruptible(p)
 #define genpd_unlock(p)			p->lock_fns->unlock(p)
 
+#define genpd_is_irq_safe(genpd)	(genpd->flags & GENPD_FLAG_IRQ_SAFE)
+
+static inline bool irq_safe_dev_in_no_sleep_domain(struct device *dev,
+		struct generic_pm_domain *genpd)
+{
+	return pm_runtime_is_irq_safe(dev) && !genpd_is_irq_safe(genpd);
+}
+
 /*
  * Get the generic PM domain for a particular struct device.
  * This validates the struct device pointer, the PM domain pointer,
@@ -343,7 +393,12 @@ static int genpd_poweroff(struct generic_pm_domain *genpd, bool is_async)
 		if (stat > PM_QOS_FLAGS_NONE)
 			return -EBUSY;
 
-		if (!pm_runtime_suspended(pdd->dev) || pdd->dev->power.irq_safe)
+		/*
+		 * Do not allow PM domain to be powered off, when an IRQ safe
+		 * device is part of a non-IRQ safe domain.
+		 */
+		if (!pm_runtime_suspended(pdd->dev) ||
+			irq_safe_dev_in_no_sleep_domain(pdd->dev, genpd))
 			not_suspended++;
 	}
 
@@ -506,10 +561,10 @@ static int genpd_runtime_suspend(struct device *dev)
 	}
 
 	/*
-	 * If power.irq_safe is set, this routine will be run with interrupts
-	 * off, so it can't use mutexes.
+	 * If power.irq_safe is set, this routine may be run with
+	 * IRQs disabled, so suspend only if the PM domain also is irq_safe.
 	 */
-	if (dev->power.irq_safe)
+	if (irq_safe_dev_in_no_sleep_domain(dev, genpd))
 		return 0;
 
 	genpd_lock(genpd);
@@ -543,8 +598,11 @@ static int genpd_runtime_resume(struct device *dev)
 	if (IS_ERR(genpd))
 		return -EINVAL;
 
-	/* If power.irq_safe, the PM domain is never powered off. */
-	if (dev->power.irq_safe) {
+	/*
+	 * As we don't power off a non IRQ safe domain, which holds
+	 * an IRQ safe device, we don't need to restore power to it.
+	 */
+	if (irq_safe_dev_in_no_sleep_domain(dev, genpd)) {
 		timed = false;
 		goto out;
 	}
@@ -586,7 +644,8 @@ static int genpd_runtime_resume(struct device *dev)
 err_stop:
 	genpd_stop_dev(genpd, dev);
 err_poweroff:
-	if (!dev->power.irq_safe) {
+	if (!dev->power.irq_safe ||
+		(dev->power.irq_safe && genpd_is_irq_safe(genpd))) {
 		genpd_lock(genpd);
 		genpd_poweroff(genpd, 0);
 		genpd_unlock(genpd);
@@ -1117,6 +1176,11 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
 	if (IS_ERR(gpd_data))
 		return PTR_ERR(gpd_data);
 
+	/* Check if we are adding an IRQ safe device to non-IRQ safe domain */
+	if (irq_safe_dev_in_no_sleep_domain(dev, genpd))
+		dev_warn_once(dev, "PM domain %s will not be powered off\n",
+				genpd->name);
+
 	genpd_lock(genpd);
 
 	if (genpd->prepared_count > 0) {
@@ -1211,6 +1275,17 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
 	    || genpd == subdomain)
 		return -EINVAL;
 
+	/*
+	 * If the domain can be powered on/off in an IRQ safe
+	 * context, ensure that the subdomain can also be
+	 * powered on/off in that context.
+	 */
+	if (!genpd_is_irq_safe(genpd) && genpd_is_irq_safe(subdomain)) {
+		WARN("Parent %s of subdomain %s must be IRQ safe\n",
+				genpd->name, subdomain->name);
+		return -EINVAL;
+	}
+
 	link = kzalloc(sizeof(*link), GFP_KERNEL);
 	if (!link)
 		return -ENOMEM;
@@ -1369,6 +1444,17 @@ static int genpd_of_parse(struct generic_pm_domain *genpd)
 	return genpd_of_parse_power_states(genpd);
 }
 
+static void genpd_lock_init(struct generic_pm_domain *genpd)
+{
+	if (genpd->flags & GENPD_FLAG_IRQ_SAFE) {
+		spin_lock_init(&genpd->slock);
+		genpd->lock_fns = &genpd_spin_fns;
+	} else {
+		mutex_init(&genpd->mlock);
+		genpd->lock_fns = &genpd_mtx_fns;
+	}
+}
+
 /**
  * pm_genpd_init - Initialize a generic I/O PM domain object.
  * @genpd: PM domain object to initialize.
@@ -1388,8 +1474,7 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
 	INIT_LIST_HEAD(&genpd->master_links);
 	INIT_LIST_HEAD(&genpd->slave_links);
 	INIT_LIST_HEAD(&genpd->dev_list);
-	mutex_init(&genpd->mlock);
-	genpd->lock_fns = &genpd_mtx_fns;
+	genpd_lock_init(genpd);
 	genpd->gov = gov;
 	INIT_WORK(&genpd->power_off_work, genpd_power_off_work_fn);
 	atomic_set(&genpd->sd_count, 0);
@@ -1833,7 +1918,9 @@ static int pm_genpd_summary_one(struct seq_file *s,
 	}
 
 	list_for_each_entry(pm_data, &genpd->dev_list, list_node) {
-		kobj_path = kobject_get_path(&pm_data->dev->kobj, GFP_KERNEL);
+		kobj_path = kobject_get_path(&pm_data->dev->kobj,
+				genpd_is_irq_safe(genpd) ?
+				GFP_ATOMIC : GFP_KERNEL);
 		if (kobj_path == NULL)
 			continue;
 
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 2d7e1bc..9b65c79 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -15,9 +15,11 @@
 #include <linux/err.h>
 #include <linux/of.h>
 #include <linux/notifier.h>
+#include <linux/spinlock.h>
 
 /* Defines used for the flags field in the struct generic_pm_domain */
 #define GENPD_FLAG_PM_CLK	(1U << 0) /* PM domain uses PM clk */
+#define GENPD_FLAG_IRQ_SAFE	(1U << 1) /* PM domain operates in atomic */
 
 #define GENPD_MAX_NUM_STATES	8 /* Number of possible low power states */
 
@@ -76,7 +78,13 @@ struct generic_pm_domain {
 	unsigned int state_count; /* number of states */
 	unsigned int state_idx; /* state that genpd will go to when off */
 	const struct genpd_lock_fns *lock_fns;
-	struct mutex mlock;
+	union {
+		struct mutex mlock;
+		struct {
+			spinlock_t slock;
+			unsigned long lock_flags;
+		};
+	};
 
 };
 
-- 
2.7.4

[PATCH 05/14] PM / doc: update device documentation for devices in IRQ safe PM domains

[Lina Iyer]

Update documentation to reflect the changes made to support IRQ safe PM
domains.

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 Documentation/power/devices.txt | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index 8ba6625..a622136 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -607,7 +607,17 @@ individually.  Instead, a set of devices sharing a power resource can be put
 into a low-power state together at the same time by turning off the shared
 power resource.  Of course, they also need to be put into the full-power state
 together, by turning the shared power resource on.  A set of devices with this
-property is often referred to as a power domain.
+property is often referred to as a power domain. A power domain may also be
+nested inside another power domain.
+
+Devices, by default, operate in process context. If a device can operate in
+IRQ safe context that has to be explicitly indicated by setting the irq_safe
+boolean inside struct generic_pm_domain to be true. Power domains by default,
+operate in process context but could have devices that are IRQ safe. Such
+power domains cannot be powered on/off during runtime PM. On the other hand,
+IRQ safe PM domains that have IRQ safe devices may be powered off when all
+the devices are in idle. An IRQ safe domain may only be attached as a
+subdomain to another IRQ safe domain.
 
 Support for power domains is provided through the pm_domain field of struct
 device.  This field is a pointer to an object of type struct dev_pm_domain,
-- 
2.7.4

[PATCH 05/14] PM / doc: update device documentation for devices in IRQ safe PM domains

[Lina Iyer]

Update documentation to reflect the changes made to support IRQ safe PM
domains.

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 Documentation/power/devices.txt | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index 8ba6625..a622136 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -607,7 +607,17 @@ individually.  Instead, a set of devices sharing a power resource can be put
 into a low-power state together at the same time by turning off the shared
 power resource.  Of course, they also need to be put into the full-power state
 together, by turning the shared power resource on.  A set of devices with this
-property is often referred to as a power domain.
+property is often referred to as a power domain. A power domain may also be
+nested inside another power domain.
+
+Devices, by default, operate in process context. If a device can operate in
+IRQ safe context that has to be explicitly indicated by setting the irq_safe
+boolean inside struct generic_pm_domain to be true. Power domains by default,
+operate in process context but could have devices that are IRQ safe. Such
+power domains cannot be powered on/off during runtime PM. On the other hand,
+IRQ safe PM domains that have IRQ safe devices may be powered off when all
+the devices are in idle. An IRQ safe domain may only be attached as a
+subdomain to another IRQ safe domain.
 
 Support for power domains is provided through the pm_domain field of struct
 device.  This field is a pointer to an object of type struct dev_pm_domain,
-- 
2.7.4

[PATCH 06/14] PM / cpu_domains: Setup PM domains for CPUs/clusters

[Lina Iyer]

Define and add Generic PM domains (genpd) for CPU clusters. Many new
SoCs group CPUs as clusters. Clusters share common resources like power
rails, caches, VFP, Coresight etc. When all CPUs in the cluster are
idle, these shared resources may also be put in their idle state.

CPUs may be associated with their domain providers in DT. The domains in
turn may be associated with their providers. This is clean way to model
the cluster hierarchy like that of ARM's big.little architecture. The
current patch expects OF support to initialize and setup CPU PM domains.

For each CPU in the DT, we identify the domain provider; initialize and
register the PM domain if isn't already registered and attach all the
CPU devices to the domain. Usually, when there are multiple clusters of
CPUs, there is a top level coherency domain that is dependent on these
individual domains. All domains thus created are marked IRQ safe
automatically and therefore may be powered down when the CPUs in the
domain are powered down by cpuidle.

Reading DT, initializing Generic PM domains, attaching CPUs to it
domains are common functionalities across ARM SoCs. Provide a common set
of APIs to setup PM domains for CPU clusters and its parents. The
platform drivers may just call of_setup_cpu_pd() to do a single step
setup of CPU domains.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Suggested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 drivers/base/power/Makefile      |   1 +
 drivers/base/power/cpu_domains.c | 288 +++++++++++++++++++++++++++++++++++++++
 include/linux/cpu_domains.h      |  37 +++++
 3 files changed, 326 insertions(+)
 create mode 100644 drivers/base/power/cpu_domains.c
 create mode 100644 include/linux/cpu_domains.h

diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile
index 5998c53..9883e89 100644
--- a/drivers/base/power/Makefile
+++ b/drivers/base/power/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_PM_SLEEP)	+= main.o wakeup.o
 obj-$(CONFIG_PM_TRACE_RTC)	+= trace.o
 obj-$(CONFIG_PM_OPP)	+= opp/
 obj-$(CONFIG_PM_GENERIC_DOMAINS)	+=  domain.o domain_governor.o
+obj-$(CONFIG_PM_GENERIC_DOMAINS_OF)	+= cpu_domains.o
 obj-$(CONFIG_HAVE_CLK)	+= clock_ops.o
 
 ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
diff --git a/drivers/base/power/cpu_domains.c b/drivers/base/power/cpu_domains.c
new file mode 100644
index 0000000..63dd45d
--- /dev/null
+++ b/drivers/base/power/cpu_domains.c
@@ -0,0 +1,288 @@
+/*
+ * drivers/base/power/cpu_domains.c - Helper functions to create CPU PM domains.
+ *
+ * Copyright (C) 2016 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/cpu_domains.h>
+#include <linux/cpu_pm.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/pm_domain.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+#include <linux/slab.h>
+
+#define CPU_PD_NAME_MAX 36
+
+struct cpu_pm_domain {
+	struct list_head link;
+	struct cpu_pd_ops ops;
+	struct generic_pm_domain *genpd;
+	struct cpu_pm_domain *parent;
+	cpumask_var_t cpus;
+};
+
+/* List of CPU PM domains we care about */
+static LIST_HEAD(of_cpu_pd_list);
+static DEFINE_MUTEX(cpu_pd_list_lock);
+
+static inline
+struct cpu_pm_domain *to_cpu_pd(struct generic_pm_domain *d)
+{
+	struct cpu_pm_domain *pd;
+	struct cpu_pm_domain *res = NULL;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(pd, &of_cpu_pd_list, link)
+		if (pd->genpd == d) {
+			res = pd;
+			break;
+		}
+	rcu_read_unlock();
+
+	return res;
+}
+
+static int cpu_pd_attach_cpu(struct cpu_pm_domain *cpu_pd, int cpu)
+{
+	int ret;
+	struct device *cpu_dev;
+
+	cpu_dev = get_cpu_device(cpu);
+	if (!cpu_dev) {
+		pr_warn("%s: Unable to get device for CPU%d\n",
+				__func__, cpu);
+		return -ENODEV;
+	}
+
+	ret = genpd_dev_pm_attach(cpu_dev);
+	if (ret)
+		dev_warn(cpu_dev,
+			"%s: Unable to attach to power-domain: %d\n",
+			__func__, ret);
+	else
+		dev_dbg(cpu_dev, "Attached to domain\n");
+
+	while (!ret && cpu_pd) {
+		cpumask_set_cpu(cpu, cpu_pd->cpus);
+		cpu_pd = cpu_pd->parent;
+	};
+
+	return ret;
+}
+
+static int cpu_pd_power_on(struct generic_pm_domain *genpd)
+{
+	struct cpu_pm_domain *pd = to_cpu_pd(genpd);
+
+	return pd->ops.power_on ? pd->ops.power_on() : 0;
+}
+
+static int cpu_pd_power_off(struct generic_pm_domain *genpd)
+{
+	struct cpu_pm_domain *pd = to_cpu_pd(genpd);
+
+	return pd->ops.power_off ? pd->ops.power_off(genpd->state_idx,
+					genpd->states[genpd->state_idx].param,
+					pd->cpus) : 0;
+}
+
+/**
+ * of_init_cpu_pm_domain() - Initialize a CPU PM domain from a device node
+ *
+ * @dn: The domain provider's device node
+ * @ops: The power_on/_off callbacks for the domain
+ *
+ * Returns the generic_pm_domain (genpd) pointer to the domain on success
+ */
+static struct generic_pm_domain *of_init_cpu_pm_domain(struct device_node *dn,
+				const struct cpu_pd_ops *ops)
+{
+	struct cpu_pm_domain *pd = NULL;
+	struct generic_pm_domain *genpd = NULL;
+	int ret = -ENOMEM;
+
+	if (!of_device_is_available(dn))
+		return ERR_PTR(-ENODEV);
+
+	genpd = kzalloc(sizeof(*genpd), GFP_KERNEL);
+	if (!genpd)
+		goto fail;
+
+	genpd->name = kstrndup(dn->full_name, CPU_PD_NAME_MAX, GFP_KERNEL);
+	if (!genpd->name)
+		goto fail;
+
+	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		goto fail;
+
+	if (!zalloc_cpumask_var(&pd->cpus, GFP_KERNEL))
+		goto fail;
+
+	pd->genpd = genpd;
+	pd->genpd->power_off = cpu_pd_power_off;
+	pd->genpd->power_on = cpu_pd_power_on;
+	pd->genpd->flags |= GENPD_FLAG_IRQ_SAFE;
+	pd->genpd->of_node = dn;
+	pd->ops.power_on = ops->power_on;
+	pd->ops.power_off = ops->power_off;
+
+	INIT_LIST_HEAD_RCU(&pd->link);
+	mutex_lock(&cpu_pd_list_lock);
+	list_add_rcu(&pd->link, &of_cpu_pd_list);
+	mutex_unlock(&cpu_pd_list_lock);
+
+	/* Register the CPU genpd */
+	pr_debug("adding %s as CPU PM domain\n", pd->genpd->name);
+	ret = pm_genpd_init(pd->genpd, &simple_qos_governor, false);
+	if (ret) {
+		pr_err("Unable to initialize domain %s\n", dn->full_name);
+		goto fail;
+	}
+
+	ret = of_genpd_add_provider_simple(dn, pd->genpd);
+	if (ret)
+		pr_warn("Unable to add genpd %s as provider\n",
+				pd->genpd->name);
+
+	return pd->genpd;
+fail:
+
+	kfree(genpd->name);
+	kfree(genpd);
+	if (pd)
+		kfree(pd->cpus);
+	kfree(pd);
+	return ERR_PTR(ret);
+}
+
+static struct generic_pm_domain *of_get_cpu_domain(struct device_node *dn,
+		const struct cpu_pd_ops *ops, int cpu)
+{
+	struct of_phandle_args args;
+	struct generic_pm_domain *genpd, *parent;
+	struct cpu_pm_domain *cpu_pd, *parent_cpu_pd;
+	int ret;
+
+	/* Do we have this domain? If not, create the domain */
+	args.np = dn;
+	args.args_count = 0;
+
+	genpd = of_genpd_get_from_provider(&args);
+	if (!IS_ERR(genpd))
+		return genpd;
+
+	genpd = of_init_cpu_pm_domain(dn, ops);
+	if (IS_ERR(genpd))
+		return genpd;
+
+	/* Is there a domain provider for this domain? */
+	ret = of_parse_phandle_with_args(dn, "power-domains",
+			"#power-domain-cells", 0, &args);
+	if (ret < 0)
+		goto skip_parent;
+
+	/* Find its parent and attach this domain to it, recursively */
+	parent = of_get_cpu_domain(args.np, ops, cpu);
+	if (IS_ERR(parent))
+		goto skip_parent;
+
+	ret = pm_genpd_add_subdomain(genpd, parent);
+	if (ret) {
+		pr_err("%s: Unable to add sub-domain (%s)\n err: %d",
+				__func__, genpd->name, ret);
+		return ERR_PTR(ret);
+	}
+
+	/*
+	 * Reference parent domain for easy access.
+	 * Note: We could be attached to a domain that is not a
+	 * CPU PM domain in that case don't reference the parent.
+	 */
+	cpu_pd = to_cpu_pd(genpd);
+	parent_cpu_pd = to_cpu_pd(parent);
+
+	if (cpu_pd && parent_cpu_pd)
+		cpu_pd->parent = parent_cpu_pd;
+
+skip_parent:
+	of_node_put(dn);
+	return genpd;
+}
+
+/**
+ * of_setup_cpu_pd_single() - Setup the PM domains for a CPU
+ *
+ * @cpu: The CPU for which the PM domain is to be set up.
+ * @ops: The PM domain suspend/resume ops for the CPU's domain
+ *
+ * If the CPU PM domain exists already, then the CPU is attached to
+ * that CPU PD. If it doesn't, the domain is created, the @ops are
+ * set for power_on/power_off callbacks and then the CPU is attached
+ * to that domain. If the domain was created outside this framework,
+ * then we do not attach the CPU to the domain.
+ */
+int of_setup_cpu_pd_single(int cpu, const struct cpu_pd_ops *ops)
+{
+
+	struct device_node *dn;
+	struct generic_pm_domain *genpd;
+	struct cpu_pm_domain *cpu_pd;
+
+	dn = of_get_cpu_node(cpu, NULL);
+	if (!dn)
+		return -ENODEV;
+
+	dn = of_parse_phandle(dn, "power-domains", 0);
+	if (!dn)
+		return -ENODEV;
+
+	/* Find the genpd for this CPU, create if not found */
+	genpd = of_get_cpu_domain(dn, ops, cpu);
+	if (IS_ERR(genpd))
+		return PTR_ERR(genpd);
+
+	of_node_put(dn);
+	cpu_pd = to_cpu_pd(genpd);
+	if (!cpu_pd) {
+		pr_err("%s: Genpd was created outside CPU PM domains\n",
+				__func__);
+		return -ENOENT;
+	}
+
+	return cpu_pd_attach_cpu(cpu_pd, cpu);
+}
+EXPORT_SYMBOL(of_setup_cpu_pd_single);
+
+/**
+ * of_setup_cpu_pd() - Setup the PM domains for all CPUs
+ *
+ * @ops: The PM domain suspend/resume ops for all the domains
+ *
+ * Setup the CPU PM domain and attach all possible CPUs to their respective
+ * domains. The domains are created if not already and then attached.
+ */
+int of_setup_cpu_pd(const struct cpu_pd_ops *ops)
+{
+	int cpu;
+	int ret;
+
+	for_each_possible_cpu(cpu) {
+		ret = of_setup_cpu_pd_single(cpu, ops);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(of_setup_cpu_pd);
diff --git a/include/linux/cpu_domains.h b/include/linux/cpu_domains.h
new file mode 100644
index 0000000..50e3321
--- /dev/null
+++ b/include/linux/cpu_domains.h
@@ -0,0 +1,37 @@
+/*
+ * include/linux/cpu_domains.h
+ *
+ * Copyright (C) 2016 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __CPU_DOMAINS_H__
+#define __CPU_DOMAINS_H__
+
+#include <linux/types.h>
+
+struct cpumask;
+
+struct cpu_pd_ops {
+	int (*power_off)(u32 state_idx, u32 param, const struct cpumask *mask);
+	int (*power_on)(void);
+};
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+int of_setup_cpu_pd_single(int cpu, const struct cpu_pd_ops *ops);
+int of_setup_cpu_pd(const struct cpu_pd_ops *ops);
+#else
+static inline int of_setup_cpu_pd_single(int cpu, const struct cpu_pd_ops *ops)
+{
+	return -ENODEV;
+}
+static inline int of_setup_cpu_pd(const struct cpu_pd_ops *ops)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
+
+#endif /* __CPU_DOMAINS_H__ */
-- 
2.7.4

[PATCH 06/14] PM / cpu_domains: Setup PM domains for CPUs/clusters

[Lina Iyer]

Define and add Generic PM domains (genpd) for CPU clusters. Many new
SoCs group CPUs as clusters. Clusters share common resources like power
rails, caches, VFP, Coresight etc. When all CPUs in the cluster are
idle, these shared resources may also be put in their idle state.

CPUs may be associated with their domain providers in DT. The domains in
turn may be associated with their providers. This is clean way to model
the cluster hierarchy like that of ARM's big.little architecture. The
current patch expects OF support to initialize and setup CPU PM domains.

For each CPU in the DT, we identify the domain provider; initialize and
register the PM domain if isn't already registered and attach all the
CPU devices to the domain. Usually, when there are multiple clusters of
CPUs, there is a top level coherency domain that is dependent on these
individual domains. All domains thus created are marked IRQ safe
automatically and therefore may be powered down when the CPUs in the
domain are powered down by cpuidle.

Reading DT, initializing Generic PM domains, attaching CPUs to it
domains are common functionalities across ARM SoCs. Provide a common set
of APIs to setup PM domains for CPU clusters and its parents. The
platform drivers may just call of_setup_cpu_pd() to do a single step
setup of CPU domains.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Suggested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 drivers/base/power/Makefile      |   1 +
 drivers/base/power/cpu_domains.c | 288 +++++++++++++++++++++++++++++++++++++++
 include/linux/cpu_domains.h      |  37 +++++
 3 files changed, 326 insertions(+)
 create mode 100644 drivers/base/power/cpu_domains.c
 create mode 100644 include/linux/cpu_domains.h

diff --git a/drivers/base/power/Makefile b/drivers/base/power/Makefile
index 5998c53..9883e89 100644
--- a/drivers/base/power/Makefile
+++ b/drivers/base/power/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_PM_SLEEP)	+= main.o wakeup.o
 obj-$(CONFIG_PM_TRACE_RTC)	+= trace.o
 obj-$(CONFIG_PM_OPP)	+= opp/
 obj-$(CONFIG_PM_GENERIC_DOMAINS)	+=  domain.o domain_governor.o
+obj-$(CONFIG_PM_GENERIC_DOMAINS_OF)	+= cpu_domains.o
 obj-$(CONFIG_HAVE_CLK)	+= clock_ops.o
 
 ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
diff --git a/drivers/base/power/cpu_domains.c b/drivers/base/power/cpu_domains.c
new file mode 100644
index 0000000..63dd45d
--- /dev/null
+++ b/drivers/base/power/cpu_domains.c
@@ -0,0 +1,288 @@
+/*
+ * drivers/base/power/cpu_domains.c - Helper functions to create CPU PM domains.
+ *
+ * Copyright (C) 2016 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/cpu_domains.h>
+#include <linux/cpu_pm.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/pm_domain.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+#include <linux/slab.h>
+
+#define CPU_PD_NAME_MAX 36
+
+struct cpu_pm_domain {
+	struct list_head link;
+	struct cpu_pd_ops ops;
+	struct generic_pm_domain *genpd;
+	struct cpu_pm_domain *parent;
+	cpumask_var_t cpus;
+};
+
+/* List of CPU PM domains we care about */
+static LIST_HEAD(of_cpu_pd_list);
+static DEFINE_MUTEX(cpu_pd_list_lock);
+
+static inline
+struct cpu_pm_domain *to_cpu_pd(struct generic_pm_domain *d)
+{
+	struct cpu_pm_domain *pd;
+	struct cpu_pm_domain *res = NULL;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(pd, &of_cpu_pd_list, link)
+		if (pd->genpd == d) {
+			res = pd;
+			break;
+		}
+	rcu_read_unlock();
+
+	return res;
+}
+
+static int cpu_pd_attach_cpu(struct cpu_pm_domain *cpu_pd, int cpu)
+{
+	int ret;
+	struct device *cpu_dev;
+
+	cpu_dev = get_cpu_device(cpu);
+	if (!cpu_dev) {
+		pr_warn("%s: Unable to get device for CPU%d\n",
+				__func__, cpu);
+		return -ENODEV;
+	}
+
+	ret = genpd_dev_pm_attach(cpu_dev);
+	if (ret)
+		dev_warn(cpu_dev,
+			"%s: Unable to attach to power-domain: %d\n",
+			__func__, ret);
+	else
+		dev_dbg(cpu_dev, "Attached to domain\n");
+
+	while (!ret && cpu_pd) {
+		cpumask_set_cpu(cpu, cpu_pd->cpus);
+		cpu_pd = cpu_pd->parent;
+	};
+
+	return ret;
+}
+
+static int cpu_pd_power_on(struct generic_pm_domain *genpd)
+{
+	struct cpu_pm_domain *pd = to_cpu_pd(genpd);
+
+	return pd->ops.power_on ? pd->ops.power_on() : 0;
+}
+
+static int cpu_pd_power_off(struct generic_pm_domain *genpd)
+{
+	struct cpu_pm_domain *pd = to_cpu_pd(genpd);
+
+	return pd->ops.power_off ? pd->ops.power_off(genpd->state_idx,
+					genpd->states[genpd->state_idx].param,
+					pd->cpus) : 0;
+}
+
+/**
+ * of_init_cpu_pm_domain() - Initialize a CPU PM domain from a device node
+ *
+ * @dn: The domain provider's device node
+ * @ops: The power_on/_off callbacks for the domain
+ *
+ * Returns the generic_pm_domain (genpd) pointer to the domain on success
+ */
+static struct generic_pm_domain *of_init_cpu_pm_domain(struct device_node *dn,
+				const struct cpu_pd_ops *ops)
+{
+	struct cpu_pm_domain *pd = NULL;
+	struct generic_pm_domain *genpd = NULL;
+	int ret = -ENOMEM;
+
+	if (!of_device_is_available(dn))
+		return ERR_PTR(-ENODEV);
+
+	genpd = kzalloc(sizeof(*genpd), GFP_KERNEL);
+	if (!genpd)
+		goto fail;
+
+	genpd->name = kstrndup(dn->full_name, CPU_PD_NAME_MAX, GFP_KERNEL);
+	if (!genpd->name)
+		goto fail;
+
+	pd = kzalloc(sizeof(*pd), GFP_KERNEL);
+	if (!pd)
+		goto fail;
+
+	if (!zalloc_cpumask_var(&pd->cpus, GFP_KERNEL))
+		goto fail;
+
+	pd->genpd = genpd;
+	pd->genpd->power_off = cpu_pd_power_off;
+	pd->genpd->power_on = cpu_pd_power_on;
+	pd->genpd->flags |= GENPD_FLAG_IRQ_SAFE;
+	pd->genpd->of_node = dn;
+	pd->ops.power_on = ops->power_on;
+	pd->ops.power_off = ops->power_off;
+
+	INIT_LIST_HEAD_RCU(&pd->link);
+	mutex_lock(&cpu_pd_list_lock);
+	list_add_rcu(&pd->link, &of_cpu_pd_list);
+	mutex_unlock(&cpu_pd_list_lock);
+
+	/* Register the CPU genpd */
+	pr_debug("adding %s as CPU PM domain\n", pd->genpd->name);
+	ret = pm_genpd_init(pd->genpd, &simple_qos_governor, false);
+	if (ret) {
+		pr_err("Unable to initialize domain %s\n", dn->full_name);
+		goto fail;
+	}
+
+	ret = of_genpd_add_provider_simple(dn, pd->genpd);
+	if (ret)
+		pr_warn("Unable to add genpd %s as provider\n",
+				pd->genpd->name);
+
+	return pd->genpd;
+fail:
+
+	kfree(genpd->name);
+	kfree(genpd);
+	if (pd)
+		kfree(pd->cpus);
+	kfree(pd);
+	return ERR_PTR(ret);
+}
+
+static struct generic_pm_domain *of_get_cpu_domain(struct device_node *dn,
+		const struct cpu_pd_ops *ops, int cpu)
+{
+	struct of_phandle_args args;
+	struct generic_pm_domain *genpd, *parent;
+	struct cpu_pm_domain *cpu_pd, *parent_cpu_pd;
+	int ret;
+
+	/* Do we have this domain? If not, create the domain */
+	args.np = dn;
+	args.args_count = 0;
+
+	genpd = of_genpd_get_from_provider(&args);
+	if (!IS_ERR(genpd))
+		return genpd;
+
+	genpd = of_init_cpu_pm_domain(dn, ops);
+	if (IS_ERR(genpd))
+		return genpd;
+
+	/* Is there a domain provider for this domain? */
+	ret = of_parse_phandle_with_args(dn, "power-domains",
+			"#power-domain-cells", 0, &args);
+	if (ret < 0)
+		goto skip_parent;
+
+	/* Find its parent and attach this domain to it, recursively */
+	parent = of_get_cpu_domain(args.np, ops, cpu);
+	if (IS_ERR(parent))
+		goto skip_parent;
+
+	ret = pm_genpd_add_subdomain(genpd, parent);
+	if (ret) {
+		pr_err("%s: Unable to add sub-domain (%s)\n err: %d",
+				__func__, genpd->name, ret);
+		return ERR_PTR(ret);
+	}
+
+	/*
+	 * Reference parent domain for easy access.
+	 * Note: We could be attached to a domain that is not a
+	 * CPU PM domain in that case don't reference the parent.
+	 */
+	cpu_pd = to_cpu_pd(genpd);
+	parent_cpu_pd = to_cpu_pd(parent);
+
+	if (cpu_pd && parent_cpu_pd)
+		cpu_pd->parent = parent_cpu_pd;
+
+skip_parent:
+	of_node_put(dn);
+	return genpd;
+}
+
+/**
+ * of_setup_cpu_pd_single() - Setup the PM domains for a CPU
+ *
+ * @cpu: The CPU for which the PM domain is to be set up.
+ * @ops: The PM domain suspend/resume ops for the CPU's domain
+ *
+ * If the CPU PM domain exists already, then the CPU is attached to
+ * that CPU PD. If it doesn't, the domain is created, the @ops are
+ * set for power_on/power_off callbacks and then the CPU is attached
+ * to that domain. If the domain was created outside this framework,
+ * then we do not attach the CPU to the domain.
+ */
+int of_setup_cpu_pd_single(int cpu, const struct cpu_pd_ops *ops)
+{
+
+	struct device_node *dn;
+	struct generic_pm_domain *genpd;
+	struct cpu_pm_domain *cpu_pd;
+
+	dn = of_get_cpu_node(cpu, NULL);
+	if (!dn)
+		return -ENODEV;
+
+	dn = of_parse_phandle(dn, "power-domains", 0);
+	if (!dn)
+		return -ENODEV;
+
+	/* Find the genpd for this CPU, create if not found */
+	genpd = of_get_cpu_domain(dn, ops, cpu);
+	if (IS_ERR(genpd))
+		return PTR_ERR(genpd);
+
+	of_node_put(dn);
+	cpu_pd = to_cpu_pd(genpd);
+	if (!cpu_pd) {
+		pr_err("%s: Genpd was created outside CPU PM domains\n",
+				__func__);
+		return -ENOENT;
+	}
+
+	return cpu_pd_attach_cpu(cpu_pd, cpu);
+}
+EXPORT_SYMBOL(of_setup_cpu_pd_single);
+
+/**
+ * of_setup_cpu_pd() - Setup the PM domains for all CPUs
+ *
+ * @ops: The PM domain suspend/resume ops for all the domains
+ *
+ * Setup the CPU PM domain and attach all possible CPUs to their respective
+ * domains. The domains are created if not already and then attached.
+ */
+int of_setup_cpu_pd(const struct cpu_pd_ops *ops)
+{
+	int cpu;
+	int ret;
+
+	for_each_possible_cpu(cpu) {
+		ret = of_setup_cpu_pd_single(cpu, ops);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(of_setup_cpu_pd);
diff --git a/include/linux/cpu_domains.h b/include/linux/cpu_domains.h
new file mode 100644
index 0000000..50e3321
--- /dev/null
+++ b/include/linux/cpu_domains.h
@@ -0,0 +1,37 @@
+/*
+ * include/linux/cpu_domains.h
+ *
+ * Copyright (C) 2016 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __CPU_DOMAINS_H__
+#define __CPU_DOMAINS_H__
+
+#include <linux/types.h>
+
+struct cpumask;
+
+struct cpu_pd_ops {
+	int (*power_off)(u32 state_idx, u32 param, const struct cpumask *mask);
+	int (*power_on)(void);
+};
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+int of_setup_cpu_pd_single(int cpu, const struct cpu_pd_ops *ops);
+int of_setup_cpu_pd(const struct cpu_pd_ops *ops);
+#else
+static inline int of_setup_cpu_pd_single(int cpu, const struct cpu_pd_ops *ops)
+{
+	return -ENODEV;
+}
+static inline int of_setup_cpu_pd(const struct cpu_pd_ops *ops)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
+
+#endif /* __CPU_DOMAINS_H__ */
-- 
2.7.4

[PATCH 07/14] ARM: cpuidle: Add runtime PM support for CPUs

[Lina Iyer]

Notify runtime PM when the CPU is going to be powered off in the idle
state. This allows for runtime PM suspend/resume of the CPU as well as
its PM domain.

We do not call into runtime PM for ARM WFI to keep the default state
simple and faster.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 drivers/cpuidle/cpuidle-arm.c | 55 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
index e342565e..3abd145 100644
--- a/drivers/cpuidle/cpuidle-arm.c
+++ b/drivers/cpuidle/cpuidle-arm.c
@@ -11,12 +11,14 @@
 
 #define pr_fmt(fmt) "CPUidle arm: " fmt
 
+#include <linux/cpu.h>
 #include <linux/cpuidle.h>
 #include <linux/cpumask.h>
 #include <linux/cpu_pm.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 
 #include <asm/cpuidle.h>
@@ -37,6 +39,7 @@ static int arm_enter_idle_state(struct cpuidle_device *dev,
 				struct cpuidle_driver *drv, int idx)
 {
 	int ret;
+	struct device *cpu_dev = get_cpu_device(dev->cpu);
 
 	if (!idx) {
 		cpu_do_idle();
@@ -46,12 +49,20 @@ static int arm_enter_idle_state(struct cpuidle_device *dev,
 	ret = cpu_pm_enter();
 	if (!ret) {
 		/*
+		 * Call runtime PM suspend on our device
+		 * Notify RCU to pay attention to critical sections
+		 * called from within runtime PM.
+		 */
+		RCU_NONIDLE(pm_runtime_put_sync_suspend(cpu_dev));
+
+		/*
 		 * Pass idle state index to cpu_suspend which in turn will
 		 * call the CPU ops suspend protocol with idle index as a
 		 * parameter.
 		 */
 		ret = arm_cpuidle_suspend(idx);
 
+		RCU_NONIDLE(pm_runtime_get_sync(cpu_dev));
 		cpu_pm_exit();
 	}
 
@@ -84,6 +95,34 @@ static const struct of_device_id arm_idle_state_match[] __initconst = {
 	{ },
 };
 
+#ifdef CONFIG_HOTPLUG_CPU
+static int arm_idle_cpu_hotplug(struct notifier_block *nb,
+			unsigned long action, void *data)
+{
+	struct device *cpu_dev = get_cpu_device(smp_processor_id());
+
+	/* Execute CPU runtime PM on that CPU */
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_DYING:
+		pm_runtime_put_sync_suspend(cpu_dev);
+		break;
+	case CPU_STARTING:
+		pm_runtime_get_sync(cpu_dev);
+		break;
+	default:
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+#else
+static int arm_idle_cpu_hotplug(struct notifier_block *nb,
+			unsigned long action, void *data)
+{
+	return NOTIFY_OK;
+}
+#endif
+
 /*
  * arm_idle_init
  *
@@ -96,6 +135,7 @@ static int __init arm_idle_init(void)
 	int cpu, ret;
 	struct cpuidle_driver *drv = &arm_idle_driver;
 	struct cpuidle_device *dev;
+	struct device *cpu_dev;
 
 	/*
 	 * Initialize idle states data, starting at index 1.
@@ -118,6 +158,16 @@ static int __init arm_idle_init(void)
 	 * idle states suspend back-end specific data
 	 */
 	for_each_possible_cpu(cpu) {
+
+		/* Initialize Runtime PM for the CPU */
+		cpu_dev = get_cpu_device(cpu);
+		pm_runtime_irq_safe(cpu_dev);
+		pm_runtime_enable(cpu_dev);
+		if (cpu_online(cpu)) {
+			pm_runtime_get_noresume(cpu_dev);
+			pm_runtime_set_active(cpu_dev);
+		}
+
 		ret = arm_cpuidle_init(cpu);
 
 		/*
@@ -148,10 +198,15 @@ static int __init arm_idle_init(void)
 		}
 	}
 
+	/* Register for hotplug notifications for runtime PM */
+	hotcpu_notifier(arm_idle_cpu_hotplug, 0);
+
 	return 0;
 out_fail:
 	while (--cpu >= 0) {
 		dev = per_cpu(cpuidle_devices, cpu);
+		cpu_dev = get_cpu_device(cpu);
+		__pm_runtime_disable(cpu_dev, false);
 		cpuidle_unregister_device(dev);
 		kfree(dev);
 	}
-- 
2.7.4

[PATCH 07/14] ARM: cpuidle: Add runtime PM support for CPUs

[Lina Iyer]

Notify runtime PM when the CPU is going to be powered off in the idle
state. This allows for runtime PM suspend/resume of the CPU as well as
its PM domain.

We do not call into runtime PM for ARM WFI to keep the default state
simple and faster.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 drivers/cpuidle/cpuidle-arm.c | 55 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
index e342565e..3abd145 100644
--- a/drivers/cpuidle/cpuidle-arm.c
+++ b/drivers/cpuidle/cpuidle-arm.c
@@ -11,12 +11,14 @@
 
 #define pr_fmt(fmt) "CPUidle arm: " fmt
 
+#include <linux/cpu.h>
 #include <linux/cpuidle.h>
 #include <linux/cpumask.h>
 #include <linux/cpu_pm.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 
 #include <asm/cpuidle.h>
@@ -37,6 +39,7 @@ static int arm_enter_idle_state(struct cpuidle_device *dev,
 				struct cpuidle_driver *drv, int idx)
 {
 	int ret;
+	struct device *cpu_dev = get_cpu_device(dev->cpu);
 
 	if (!idx) {
 		cpu_do_idle();
@@ -46,12 +49,20 @@ static int arm_enter_idle_state(struct cpuidle_device *dev,
 	ret = cpu_pm_enter();
 	if (!ret) {
 		/*
+		 * Call runtime PM suspend on our device
+		 * Notify RCU to pay attention to critical sections
+		 * called from within runtime PM.
+		 */
+		RCU_NONIDLE(pm_runtime_put_sync_suspend(cpu_dev));
+
+		/*
 		 * Pass idle state index to cpu_suspend which in turn will
 		 * call the CPU ops suspend protocol with idle index as a
 		 * parameter.
 		 */
 		ret = arm_cpuidle_suspend(idx);
 
+		RCU_NONIDLE(pm_runtime_get_sync(cpu_dev));
 		cpu_pm_exit();
 	}
 
@@ -84,6 +95,34 @@ static const struct of_device_id arm_idle_state_match[] __initconst = {
 	{ },
 };
 
+#ifdef CONFIG_HOTPLUG_CPU
+static int arm_idle_cpu_hotplug(struct notifier_block *nb,
+			unsigned long action, void *data)
+{
+	struct device *cpu_dev = get_cpu_device(smp_processor_id());
+
+	/* Execute CPU runtime PM on that CPU */
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_DYING:
+		pm_runtime_put_sync_suspend(cpu_dev);
+		break;
+	case CPU_STARTING:
+		pm_runtime_get_sync(cpu_dev);
+		break;
+	default:
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+#else
+static int arm_idle_cpu_hotplug(struct notifier_block *nb,
+			unsigned long action, void *data)
+{
+	return NOTIFY_OK;
+}
+#endif
+
 /*
  * arm_idle_init
  *
@@ -96,6 +135,7 @@ static int __init arm_idle_init(void)
 	int cpu, ret;
 	struct cpuidle_driver *drv = &arm_idle_driver;
 	struct cpuidle_device *dev;
+	struct device *cpu_dev;
 
 	/*
 	 * Initialize idle states data, starting at index 1.
@@ -118,6 +158,16 @@ static int __init arm_idle_init(void)
 	 * idle states suspend back-end specific data
 	 */
 	for_each_possible_cpu(cpu) {
+
+		/* Initialize Runtime PM for the CPU */
+		cpu_dev = get_cpu_device(cpu);
+		pm_runtime_irq_safe(cpu_dev);
+		pm_runtime_enable(cpu_dev);
+		if (cpu_online(cpu)) {
+			pm_runtime_get_noresume(cpu_dev);
+			pm_runtime_set_active(cpu_dev);
+		}
+
 		ret = arm_cpuidle_init(cpu);
 
 		/*
@@ -148,10 +198,15 @@ static int __init arm_idle_init(void)
 		}
 	}
 
+	/* Register for hotplug notifications for runtime PM */
+	hotcpu_notifier(arm_idle_cpu_hotplug, 0);
+
 	return 0;
 out_fail:
 	while (--cpu >= 0) {
 		dev = per_cpu(cpuidle_devices, cpu);
+		cpu_dev = get_cpu_device(cpu);
+		__pm_runtime_disable(cpu_dev, false);
 		cpuidle_unregister_device(dev);
 		kfree(dev);
 	}
-- 
2.7.4

[PATCH 08/14] timer: Export next wake up of a CPU

[Lina Iyer]

Knowing the sleep length of the CPU is useful for the power state
determination on idle. However, when the common sleep time between
multiple CPUs is needed, the sleep length of a CPU is not useful.

By reading the next wake up event of a CPU, governors can determine the
first CPU to wake up (due to timer) amongst a cluster of CPUs and the
sleep time available between the last CPU to idle and the first CPU to
resume. This information is useful to determine if the caches and other
common hardware blocks can also be put in idle during this common period
of inactivity.

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 include/linux/tick.h     | 10 ++++++++++
 kernel/time/tick-sched.c | 13 +++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/include/linux/tick.h b/include/linux/tick.h
index 62be0786..9535141 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -117,6 +117,7 @@ extern void tick_nohz_idle_enter(void);
 extern void tick_nohz_idle_exit(void);
 extern void tick_nohz_irq_exit(void);
 extern ktime_t tick_nohz_get_sleep_length(void);
+extern ktime_t tick_nohz_get_next_wakeup(int cpu);
 extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
 #else /* !CONFIG_NO_HZ_COMMON */
@@ -131,6 +132,15 @@ static inline ktime_t tick_nohz_get_sleep_length(void)
 
 	return len;
 }
+
+static inline ktime_t tick_nohz_get_next_wakeup(int cpu)
+{
+	ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
+
+	/* Next wake up is the tick period, assume it starts now */
+	return ktime_add(len, ktime_get());
+}
+
 static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
 static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
 #endif /* !CONFIG_NO_HZ_COMMON */
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 536ada8..addf3235 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -979,6 +979,19 @@ ktime_t tick_nohz_get_sleep_length(void)
 	return ts->sleep_length;
 }
 
+/**
+ * tick_nohz_get_next_wakeup - return the next wake up of the CPU
+ *
+ * Called with interrupts disabled on the cpu
+ */
+ktime_t tick_nohz_get_next_wakeup(int cpu)
+{
+	struct clock_event_device *dev =
+			per_cpu(tick_cpu_device.evtdev, cpu);
+
+	return dev->next_event;
+}
+
 static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
 {
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
-- 
2.7.4

[PATCH 08/14] timer: Export next wake up of a CPU

[Lina Iyer]

Knowing the sleep length of the CPU is useful for the power state
determination on idle. However, when the common sleep time between
multiple CPUs is needed, the sleep length of a CPU is not useful.

By reading the next wake up event of a CPU, governors can determine the
first CPU to wake up (due to timer) amongst a cluster of CPUs and the
sleep time available between the last CPU to idle and the first CPU to
resume. This information is useful to determine if the caches and other
common hardware blocks can also be put in idle during this common period
of inactivity.

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 include/linux/tick.h     | 10 ++++++++++
 kernel/time/tick-sched.c | 13 +++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/include/linux/tick.h b/include/linux/tick.h
index 62be0786..9535141 100644
--- a/include/linux/tick.h
+++ b/include/linux/tick.h
@@ -117,6 +117,7 @@ extern void tick_nohz_idle_enter(void);
 extern void tick_nohz_idle_exit(void);
 extern void tick_nohz_irq_exit(void);
 extern ktime_t tick_nohz_get_sleep_length(void);
+extern ktime_t tick_nohz_get_next_wakeup(int cpu);
 extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
 extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
 #else /* !CONFIG_NO_HZ_COMMON */
@@ -131,6 +132,15 @@ static inline ktime_t tick_nohz_get_sleep_length(void)
 
 	return len;
 }
+
+static inline ktime_t tick_nohz_get_next_wakeup(int cpu)
+{
+	ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
+
+	/* Next wake up is the tick period, assume it starts now */
+	return ktime_add(len, ktime_get());
+}
+
 static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
 static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
 #endif /* !CONFIG_NO_HZ_COMMON */
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 536ada8..addf3235 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -979,6 +979,19 @@ ktime_t tick_nohz_get_sleep_length(void)
 	return ts->sleep_length;
 }
 
+/**
+ * tick_nohz_get_next_wakeup - return the next wake up of the CPU
+ *
+ * Called with interrupts disabled on the cpu
+ */
+ktime_t tick_nohz_get_next_wakeup(int cpu)
+{
+	struct clock_event_device *dev =
+			per_cpu(tick_cpu_device.evtdev, cpu);
+
+	return dev->next_event;
+}
+
 static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
 {
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
-- 
2.7.4

[PATCH 09/14] PM / cpu_domains: Add PM Domain governor for CPUs

[Lina Iyer]

A PM domain comprising of CPUs may be powered off when all the CPUs in
the domain are powered down. Powering down a CPU domain is generally a
expensive operation and therefore the power performance trade offs
should be considered. The time between the last CPU powering down and
the first CPU powering up in a domain, is the time available for the
domain to sleep. Ideally, the sleep time of the domain should fulfill
the residency requirement of the domains' idle state.

To do this effectively, read the time before the wakeup of the cluster's
CPUs and ensure that the domain's idle state sleep time guarantees the
QoS requirements of each of the CPU, the PM QoS CPU_DMA_LATENCY and the
state's residency.

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 drivers/base/power/cpu_domains.c | 80 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 79 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/cpu_domains.c b/drivers/base/power/cpu_domains.c
index 63dd45d..1803fde 100644
--- a/drivers/base/power/cpu_domains.c
+++ b/drivers/base/power/cpu_domains.c
@@ -17,9 +17,12 @@
 #include <linux/list.h>
 #include <linux/of.h>
 #include <linux/pm_domain.h>
+#include <linux/pm_qos.h>
+#include <linux/pm_runtime.h>
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
 #include <linux/slab.h>
+#include <linux/tick.h>
 
 #define CPU_PD_NAME_MAX 36
 
@@ -52,6 +55,81 @@ struct cpu_pm_domain *to_cpu_pd(struct generic_pm_domain *d)
 	return res;
 }
 
+static bool cpu_pd_down_ok(struct dev_pm_domain *pd)
+{
+	struct generic_pm_domain *genpd = pd_to_genpd(pd);
+	struct cpu_pm_domain *cpu_pd = to_cpu_pd(genpd);
+	int qos_ns = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
+	u64 sleep_ns;
+	ktime_t earliest, next_wakeup;
+	int cpu;
+	int i;
+
+	/* Reset the last set genpd state, default to index 0 */
+	genpd->state_idx = 0;
+
+	/* We don't want to power down, if QoS is 0 */
+	if (!qos_ns)
+		return false;
+
+	/*
+	 * Find the sleep time for the cluster.
+	 * The time between now and the first wake up of any CPU that
+	 * are in this domain hierarchy is the time available for the
+	 * domain to be idle.
+	 *
+	 * We only care about the next wakeup for any online CPU in that
+	 * cluster. Hotplug off any of the CPUs that we care about will
+	 * wait on the genpd lock, until we are done. Any other CPU hotplug
+	 * is not of consequence to our sleep time.
+	 */
+	earliest = ktime_set(KTIME_SEC_MAX, 0);
+	for_each_cpu_and(cpu, cpu_pd->cpus, cpu_online_mask) {
+		next_wakeup = tick_nohz_get_next_wakeup(cpu);
+		if (earliest.tv64 > next_wakeup.tv64)
+			earliest = next_wakeup;
+	}
+
+	sleep_ns = ktime_to_ns(ktime_sub(earliest, ktime_get()));
+	if (sleep_ns <= 0)
+		return false;
+
+	/*
+	 * Find the deepest sleep state that satisfies the residency
+	 * requirement and the QoS constraint
+	 */
+	for (i = genpd->state_count - 1; i >= 0; i--) {
+		u64 state_sleep_ns;
+
+		state_sleep_ns = genpd->states[i].power_off_latency_ns +
+			genpd->states[i].power_on_latency_ns +
+			genpd->states[i].residency_ns;
+
+		/*
+		 * If we can't sleep to save power in the state, move on
+		 * to the next lower idle state.
+		 */
+		if (state_sleep_ns > sleep_ns)
+			continue;
+
+		/*
+		 * We also don't want to sleep more than we should to
+		 * gaurantee QoS.
+		 */
+		if (state_sleep_ns < (qos_ns * NSEC_PER_USEC))
+			break;
+	}
+
+	if (i >= 0)
+		genpd->state_idx = i;
+
+	return (i >= 0);
+}
+
+static struct dev_power_governor cpu_pd_gov = {
+	.power_down_ok = cpu_pd_down_ok,
+};
+
 static int cpu_pd_attach_cpu(struct cpu_pm_domain *cpu_pd, int cpu)
 {
 	int ret;
@@ -144,7 +222,7 @@ static struct generic_pm_domain *of_init_cpu_pm_domain(struct device_node *dn,
 
 	/* Register the CPU genpd */
 	pr_debug("adding %s as CPU PM domain\n", pd->genpd->name);
-	ret = pm_genpd_init(pd->genpd, &simple_qos_governor, false);
+	ret = pm_genpd_init(pd->genpd, &cpu_pd_gov, false);
 	if (ret) {
 		pr_err("Unable to initialize domain %s\n", dn->full_name);
 		goto fail;
-- 
2.7.4

[PATCH 09/14] PM / cpu_domains: Add PM Domain governor for CPUs

[Lina Iyer]

A PM domain comprising of CPUs may be powered off when all the CPUs in
the domain are powered down. Powering down a CPU domain is generally a
expensive operation and therefore the power performance trade offs
should be considered. The time between the last CPU powering down and
the first CPU powering up in a domain, is the time available for the
domain to sleep. Ideally, the sleep time of the domain should fulfill
the residency requirement of the domains' idle state.

To do this effectively, read the time before the wakeup of the cluster's
CPUs and ensure that the domain's idle state sleep time guarantees the
QoS requirements of each of the CPU, the PM QoS CPU_DMA_LATENCY and the
state's residency.

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 drivers/base/power/cpu_domains.c | 80 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 79 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/cpu_domains.c b/drivers/base/power/cpu_domains.c
index 63dd45d..1803fde 100644
--- a/drivers/base/power/cpu_domains.c
+++ b/drivers/base/power/cpu_domains.c
@@ -17,9 +17,12 @@
 #include <linux/list.h>
 #include <linux/of.h>
 #include <linux/pm_domain.h>
+#include <linux/pm_qos.h>
+#include <linux/pm_runtime.h>
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
 #include <linux/slab.h>
+#include <linux/tick.h>
 
 #define CPU_PD_NAME_MAX 36
 
@@ -52,6 +55,81 @@ struct cpu_pm_domain *to_cpu_pd(struct generic_pm_domain *d)
 	return res;
 }
 
+static bool cpu_pd_down_ok(struct dev_pm_domain *pd)
+{
+	struct generic_pm_domain *genpd = pd_to_genpd(pd);
+	struct cpu_pm_domain *cpu_pd = to_cpu_pd(genpd);
+	int qos_ns = pm_qos_request(PM_QOS_CPU_DMA_LATENCY);
+	u64 sleep_ns;
+	ktime_t earliest, next_wakeup;
+	int cpu;
+	int i;
+
+	/* Reset the last set genpd state, default to index 0 */
+	genpd->state_idx = 0;
+
+	/* We don't want to power down, if QoS is 0 */
+	if (!qos_ns)
+		return false;
+
+	/*
+	 * Find the sleep time for the cluster.
+	 * The time between now and the first wake up of any CPU that
+	 * are in this domain hierarchy is the time available for the
+	 * domain to be idle.
+	 *
+	 * We only care about the next wakeup for any online CPU in that
+	 * cluster. Hotplug off any of the CPUs that we care about will
+	 * wait on the genpd lock, until we are done. Any other CPU hotplug
+	 * is not of consequence to our sleep time.
+	 */
+	earliest = ktime_set(KTIME_SEC_MAX, 0);
+	for_each_cpu_and(cpu, cpu_pd->cpus, cpu_online_mask) {
+		next_wakeup = tick_nohz_get_next_wakeup(cpu);
+		if (earliest.tv64 > next_wakeup.tv64)
+			earliest = next_wakeup;
+	}
+
+	sleep_ns = ktime_to_ns(ktime_sub(earliest, ktime_get()));
+	if (sleep_ns <= 0)
+		return false;
+
+	/*
+	 * Find the deepest sleep state that satisfies the residency
+	 * requirement and the QoS constraint
+	 */
+	for (i = genpd->state_count - 1; i >= 0; i--) {
+		u64 state_sleep_ns;
+
+		state_sleep_ns = genpd->states[i].power_off_latency_ns +
+			genpd->states[i].power_on_latency_ns +
+			genpd->states[i].residency_ns;
+
+		/*
+		 * If we can't sleep to save power in the state, move on
+		 * to the next lower idle state.
+		 */
+		if (state_sleep_ns > sleep_ns)
+			continue;
+
+		/*
+		 * We also don't want to sleep more than we should to
+		 * gaurantee QoS.
+		 */
+		if (state_sleep_ns < (qos_ns * NSEC_PER_USEC))
+			break;
+	}
+
+	if (i >= 0)
+		genpd->state_idx = i;
+
+	return (i >= 0);
+}
+
+static struct dev_power_governor cpu_pd_gov = {
+	.power_down_ok = cpu_pd_down_ok,
+};
+
 static int cpu_pd_attach_cpu(struct cpu_pm_domain *cpu_pd, int cpu)
 {
 	int ret;
@@ -144,7 +222,7 @@ static struct generic_pm_domain *of_init_cpu_pm_domain(struct device_node *dn,
 
 	/* Register the CPU genpd */
 	pr_debug("adding %s as CPU PM domain\n", pd->genpd->name);
-	ret = pm_genpd_init(pd->genpd, &simple_qos_governor, false);
+	ret = pm_genpd_init(pd->genpd, &cpu_pd_gov, false);
 	if (ret) {
 		pr_err("Unable to initialize domain %s\n", dn->full_name);
 		goto fail;
-- 
2.7.4

[PATCH 10/14] doc / cpu_domains: Describe CPU PM domains setup and governor

[Lina Iyer]

A generic CPU PM domain functionality is provided by
drivers/base/power/cpu_domains.c. This document describes the generic
usecase of CPU's PM domains, the setup of such domains and a CPU
specific genpd governor.

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 Documentation/power/cpu_domains.txt | 79 +++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 Documentation/power/cpu_domains.txt

diff --git a/Documentation/power/cpu_domains.txt b/Documentation/power/cpu_domains.txt
new file mode 100644
index 0000000..bd99e92
--- /dev/null
+++ b/Documentation/power/cpu_domains.txt
@@ -0,0 +1,79 @@
+CPU PM domains
+==============
+
+Newer CPUs are grouped in SoCs as clusters. A cluster in addition to the CPUs
+may have caches, floating point units and other architecture specific power
+controller that share resources when any of the CPUs are active. When the CPUs
+are in idle, some of these cluster components may also idle. A cluster may
+also be nested inside another cluster that provides common coherency
+interfaces to share data between the clusters. The organization of such
+clusters and CPU may be descibed in DT, since they are SoC specific.
+
+CPUIdle framework enables the CPUs to determine the sleep time and enter low
+power state to save power during periods of idle. CPUs in a cluster may enter
+and exit idle state independently of each other. During the time when all the
+CPUs are in idle state, the cluster may safely put some of the shared
+resources in their idle state. The time between the last CPU to enter idle and
+the first CPU to wake up is the time available for the cluster to enter its
+idle state.
+
+When SoCs power down the CPU during cpuidle, they generally have supplemental
+hardware that can handshake with the CPU with a signal that indicates that the
+CPU has stopped execution. The hardware is also responsible for warm booting
+the CPU on receiving an interrupt. In a cluster architecture, common resources
+that are shared by a cluster may also be powered down by an external
+microcontroller or a processor. The microcontroller may be programmed in
+advance to put the hardware blocks in a low power state, when the last active
+CPU sends the idle signal. When the signal is received, the microcontroller
+may trigger the hardware blocks to enter their low power state. When an
+interrupt to wakeup the processor is received, the microcontroller is
+responsible for bringing up the hardware blocks to its active state, before
+waking up the CPU. The timelines for such operations should be in the
+acceptable range for for CPU idle to get power benefits.
+
+CPU PM Domain Setup
+-------------------
+
+PM domains are represented in the DT as domain consumers and providers. A
+device may have a domain provider and a domain provider may support multiple
+domain consumers. Domains like clusters, may also be nested inside one
+another. A domain that has no active consumer, may be powered off and any
+resuming consumer would trigger the domain back to active. Parent domains may
+be powered off when the child domains are powered off. The CPU cluster can be
+fashioned as a PM domain. When the CPU devices are powered off, the PM domain
+may be powered off.
+
+Device idle is reference counted by runtime PM. When there is no active need
+for the device, runtime PM invokes callbacks to suspend the parent domain.
+Generic PM domain (genpd) handles the hierarchy of devices, domains and the
+reference counting of objects leading to last man down and first man up in the
+domain. The CPU domains helper functions defines PM domains for each CPU
+cluster and attaches the CPU devices to the respective PM domains.
+
+Platform drivers may use the following API to register their CPU PM domains.
+
+of_setup_cpu_pd() -
+Provides a single step registration of the CPU PM domain and attach CPUs to
+the genpd. Platform drivers may additionally register callbacks for power_on
+and power_off operations for the PM domain.
+
+of_setup_cpu_pd_single() -
+Define PM domain for a single CPU and attach the CPU to its domain.
+
+
+CPU PM Domain governor
+----------------------
+
+CPUs have a unique ability to determine their next wakeup. CPUs may wake up
+for known timer interrupts and unknown interrupts from idle. Prediction
+algorithms and heuristic based algorithms like the Menu governor for cpuidle
+can determine the next wakeup of the CPU. However, determining the wakeup
+across a group of CPUs is a tough problem to solve.
+
+A simplistic approach would be to resort to known wakeups of the CPUs in
+determining the next wakeup of any CPU in the cluster. The CPU PM domain
+governor does just that. By looking into the tick device of the CPUs, the
+governor can determine the sleep time between the last CPU and the first
+scheduled wakeup of any CPU in that domain. This combined with the PM QoS
+requirement for CPU_DMA_LATENCY can be used to determine the deepest possible
+idle state of the CPU domain.
-- 
2.7.4

[PATCH 10/14] doc / cpu_domains: Describe CPU PM domains setup and governor

[Lina Iyer]

A generic CPU PM domain functionality is provided by
drivers/base/power/cpu_domains.c. This document describes the generic
usecase of CPU's PM domains, the setup of such domains and a CPU
specific genpd governor.

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 Documentation/power/cpu_domains.txt | 79 +++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 Documentation/power/cpu_domains.txt

diff --git a/Documentation/power/cpu_domains.txt b/Documentation/power/cpu_domains.txt
new file mode 100644
index 0000000..bd99e92
--- /dev/null
+++ b/Documentation/power/cpu_domains.txt
@@ -0,0 +1,79 @@
+CPU PM domains
+==============
+
+Newer CPUs are grouped in SoCs as clusters. A cluster in addition to the CPUs
+may have caches, floating point units and other architecture specific power
+controller that share resources when any of the CPUs are active. When the CPUs
+are in idle, some of these cluster components may also idle. A cluster may
+also be nested inside another cluster that provides common coherency
+interfaces to share data between the clusters. The organization of such
+clusters and CPU may be descibed in DT, since they are SoC specific.
+
+CPUIdle framework enables the CPUs to determine the sleep time and enter low
+power state to save power during periods of idle. CPUs in a cluster may enter
+and exit idle state independently of each other. During the time when all the
+CPUs are in idle state, the cluster may safely put some of the shared
+resources in their idle state. The time between the last CPU to enter idle and
+the first CPU to wake up is the time available for the cluster to enter its
+idle state.
+
+When SoCs power down the CPU during cpuidle, they generally have supplemental
+hardware that can handshake with the CPU with a signal that indicates that the
+CPU has stopped execution. The hardware is also responsible for warm booting
+the CPU on receiving an interrupt. In a cluster architecture, common resources
+that are shared by a cluster may also be powered down by an external
+microcontroller or a processor. The microcontroller may be programmed in
+advance to put the hardware blocks in a low power state, when the last active
+CPU sends the idle signal. When the signal is received, the microcontroller
+may trigger the hardware blocks to enter their low power state. When an
+interrupt to wakeup the processor is received, the microcontroller is
+responsible for bringing up the hardware blocks to its active state, before
+waking up the CPU. The timelines for such operations should be in the
+acceptable range for for CPU idle to get power benefits.
+
+CPU PM Domain Setup
+-------------------
+
+PM domains are represented in the DT as domain consumers and providers. A
+device may have a domain provider and a domain provider may support multiple
+domain consumers. Domains like clusters, may also be nested inside one
+another. A domain that has no active consumer, may be powered off and any
+resuming consumer would trigger the domain back to active. Parent domains may
+be powered off when the child domains are powered off. The CPU cluster can be
+fashioned as a PM domain. When the CPU devices are powered off, the PM domain
+may be powered off.
+
+Device idle is reference counted by runtime PM. When there is no active need
+for the device, runtime PM invokes callbacks to suspend the parent domain.
+Generic PM domain (genpd) handles the hierarchy of devices, domains and the
+reference counting of objects leading to last man down and first man up in the
+domain. The CPU domains helper functions defines PM domains for each CPU
+cluster and attaches the CPU devices to the respective PM domains.
+
+Platform drivers may use the following API to register their CPU PM domains.
+
+of_setup_cpu_pd() -
+Provides a single step registration of the CPU PM domain and attach CPUs to
+the genpd. Platform drivers may additionally register callbacks for power_on
+and power_off operations for the PM domain.
+
+of_setup_cpu_pd_single() -
+Define PM domain for a single CPU and attach the CPU to its domain.
+
+
+CPU PM Domain governor
+----------------------
+
+CPUs have a unique ability to determine their next wakeup. CPUs may wake up
+for known timer interrupts and unknown interrupts from idle. Prediction
+algorithms and heuristic based algorithms like the Menu governor for cpuidle
+can determine the next wakeup of the CPU. However, determining the wakeup
+across a group of CPUs is a tough problem to solve.
+
+A simplistic approach would be to resort to known wakeups of the CPUs in
+determining the next wakeup of any CPU in the cluster. The CPU PM domain
+governor does just that. By looking into the tick device of the CPUs, the
+governor can determine the sleep time between the last CPU and the first
+scheduled wakeup of any CPU in that domain. This combined with the PM QoS
+requirement for CPU_DMA_LATENCY can be used to determine the deepest possible
+idle state of the CPU domain.
-- 
2.7.4

[PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Lina Iyer]

PSCI firmware v1.0 onwards may support 2 different modes for
CPU_SUSPEND. Platform coordinated mode is the default and every firmware
should support it. OS Initiated mode is optional for the firmware to
implement and allow Linux to make an better decision on the state of
the CPU cluster heirarchy.

With the kernel capable of deciding the state for CPU cluster and
coherency domains, the OS Initiated mode may now be used by the kernel,
provided the firmware supports it. SET_SUSPEND_MODE is a PSCI function
available on v1.0 onwards and can be used to set the mode in the
firmware.

Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
[Ulf: Rebased on 4.7 rc1]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/firmware/psci.c   | 22 +++++++++++++++++++++-
 include/uapi/linux/psci.h |  5 +++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 03e0458..3920aba 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -52,6 +52,7 @@
  * require cooperation with a Trusted OS driver.
  */
 static int resident_cpu = -1;
+static bool psci_has_osi_pd;
 
 bool psci_tos_resident_on(int cpu)
 {
@@ -563,10 +564,29 @@ out_put_node:
 	return err;
 }
 
+static int __init psci_1_0_init(struct device_node *np)
+{
+	int ret;
+
+	ret = psci_0_2_init(np);
+	if (ret)
+		return ret;
+
+	/* Check if PSCI OSI mode is available */
+	ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
+	if (ret & PSCI_1_0_OS_INITIATED) {
+		ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
+		if (!ret)
+			psci_has_osi_pd = true;
+	}
+
+	return 0;
+}
+
 static const struct of_device_id psci_of_match[] __initconst = {
 	{ .compatible = "arm,psci",	.data = psci_0_1_init},
 	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
-	{ .compatible = "arm,psci-1.0",	.data = psci_0_2_init},
+	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
 	{},
 };
 
diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
index 3d7a0fc..7dd778e 100644
--- a/include/uapi/linux/psci.h
+++ b/include/uapi/linux/psci.h
@@ -48,6 +48,7 @@
 
 #define PSCI_1_0_FN_PSCI_FEATURES		PSCI_0_2_FN(10)
 #define PSCI_1_0_FN_SYSTEM_SUSPEND		PSCI_0_2_FN(14)
+#define PSCI_1_0_FN_SET_SUSPEND_MODE		PSCI_0_2_FN(15)
 
 #define PSCI_1_0_FN64_SYSTEM_SUSPEND		PSCI_0_2_FN64(14)
 
@@ -93,6 +94,10 @@
 #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK	\
 			(0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)
 
+#define PSCI_1_0_OS_INITIATED			BIT(0)
+#define PSCI_1_0_SUSPEND_MODE_PC		0
+#define PSCI_1_0_SUSPEND_MODE_OSI		1
+
 /* PSCI return values (inclusive of all PSCI versions) */
 #define PSCI_RET_SUCCESS			0
 #define PSCI_RET_NOT_SUPPORTED			-1
-- 
2.7.4

[PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Lina Iyer]

PSCI firmware v1.0 onwards may support 2 different modes for
CPU_SUSPEND. Platform coordinated mode is the default and every firmware
should support it. OS Initiated mode is optional for the firmware to
implement and allow Linux to make an better decision on the state of
the CPU cluster heirarchy.

With the kernel capable of deciding the state for CPU cluster and
coherency domains, the OS Initiated mode may now be used by the kernel,
provided the firmware supports it. SET_SUSPEND_MODE is a PSCI function
available on v1.0 onwards and can be used to set the mode in the
firmware.

Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
[Ulf: Rebased on 4.7 rc1]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/firmware/psci.c   | 22 +++++++++++++++++++++-
 include/uapi/linux/psci.h |  5 +++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 03e0458..3920aba 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -52,6 +52,7 @@
  * require cooperation with a Trusted OS driver.
  */
 static int resident_cpu = -1;
+static bool psci_has_osi_pd;
 
 bool psci_tos_resident_on(int cpu)
 {
@@ -563,10 +564,29 @@ out_put_node:
 	return err;
 }
 
+static int __init psci_1_0_init(struct device_node *np)
+{
+	int ret;
+
+	ret = psci_0_2_init(np);
+	if (ret)
+		return ret;
+
+	/* Check if PSCI OSI mode is available */
+	ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
+	if (ret & PSCI_1_0_OS_INITIATED) {
+		ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
+		if (!ret)
+			psci_has_osi_pd = true;
+	}
+
+	return 0;
+}
+
 static const struct of_device_id psci_of_match[] __initconst = {
 	{ .compatible = "arm,psci",	.data = psci_0_1_init},
 	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
-	{ .compatible = "arm,psci-1.0",	.data = psci_0_2_init},
+	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
 	{},
 };
 
diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
index 3d7a0fc..7dd778e 100644
--- a/include/uapi/linux/psci.h
+++ b/include/uapi/linux/psci.h
@@ -48,6 +48,7 @@
 
 #define PSCI_1_0_FN_PSCI_FEATURES		PSCI_0_2_FN(10)
 #define PSCI_1_0_FN_SYSTEM_SUSPEND		PSCI_0_2_FN(14)
+#define PSCI_1_0_FN_SET_SUSPEND_MODE		PSCI_0_2_FN(15)
 
 #define PSCI_1_0_FN64_SYSTEM_SUSPEND		PSCI_0_2_FN64(14)
 
@@ -93,6 +94,10 @@
 #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK	\
 			(0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)
 
+#define PSCI_1_0_OS_INITIATED			BIT(0)
+#define PSCI_1_0_SUSPEND_MODE_PC		0
+#define PSCI_1_0_SUSPEND_MODE_OSI		1
+
 /* PSCI return values (inclusive of all PSCI versions) */
 #define PSCI_RET_SUCCESS			0
 #define PSCI_RET_NOT_SUPPORTED			-1
-- 
2.7.4

[PATCH 12/14] drivers: firmware: psci: Support cluster idle states for OS-Initiated

[Lina Iyer]

PSCI OS initiated firmware may allow Linux to determine the state of the
CPU cluster and the cluster at coherency level to enter idle states when
there are no active CPUs. Since Linux has a better idea of the QoS and
the wakeup pattern of the CPUs, the cluster idle states may be better
determined by the OS instead of the firmware.

The last CPU entering idle in a cluster, is responsible for selecting
the state of the cluster. Only one CPU in a cluster may provide the
cluster idle state to the firmware. Similarly, the last CPU in the
system may provide the state of the coherency domain along with the
cluster and the CPU state IDs.

Utilize the CPU PM domain framework's helper functions to build up the
hierarchy of cluster topology using Generic PM domains. We provide
callbacks for domain power_on and power_off. By appending the state IDs
at each domain level in the -power_off() callbacks, we build up a
composite state ID that can be passed onto the firmware to idle the CPU,
the cluster and the coherency interface.

Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 drivers/firmware/psci.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 67 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 3920aba..01ec0d5 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -15,6 +15,7 @@
 
 #include <linux/arm-smccc.h>
 #include <linux/cpuidle.h>
+#include <linux/cpu_domains.h>
 #include <linux/errno.h>
 #include <linux/linkage.h>
 #include <linux/of.h>
@@ -53,6 +54,17 @@
  */
 static int resident_cpu = -1;
 static bool psci_has_osi_pd;
+static DEFINE_PER_CPU(u32, cluster_state_id);
+
+static inline u32 psci_get_composite_state_id(u32 cpu_state)
+{
+	return cpu_state | this_cpu_read(cluster_state_id);
+}
+
+static inline void psci_reset_composite_state_id(void)
+{
+	this_cpu_write(cluster_state_id, 0);
+}
 
 bool psci_tos_resident_on(int cpu)
 {
@@ -179,6 +191,8 @@ static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
 
 	fn = psci_function_id[PSCI_FN_CPU_ON];
 	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
+	/* Reset CPU cluster states */
+	psci_reset_composite_state_id();
 	return psci_to_linux_errno(err);
 }
 
@@ -250,6 +264,34 @@ static int __init psci_features(u32 psci_func_id)
 
 #ifdef CONFIG_CPU_IDLE
 static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
+static bool psci_suspend_mode_is_osi;
+
+static int psci_set_suspend_mode_osi(bool enable)
+{
+	int ret;
+	int mode;
+
+	if (enable && !psci_has_osi_pd)
+		return -ENODEV;
+
+	if (enable == psci_suspend_mode_is_osi)
+		return 0;
+
+	mode = enable ? PSCI_1_0_SUSPEND_MODE_OSI : PSCI_1_0_SUSPEND_MODE_PC;
+	ret = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE,
+			     mode, 0, 0);
+	if (!ret)
+		psci_suspend_mode_is_osi = enable;
+
+	return psci_to_linux_errno(ret);
+}
+
+static int psci_pd_power_off(u32 state_idx, u32 param,
+		const struct cpumask *mask)
+{
+	__this_cpu_add(cluster_state_id, param);
+	return 0;
+}
 
 static int psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
 {
@@ -304,6 +346,20 @@ static int psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
 	}
 	/* Idle states parsed correctly, initialize per-cpu pointer */
 	per_cpu(psci_power_state, cpu) = psci_states;
+
+	if (psci_has_osi_pd) {
+		int ret;
+		const struct cpu_pd_ops psci_pd_ops = {
+			.power_off = psci_pd_power_off,
+		};
+
+		ret = of_setup_cpu_pd_single(cpu, &psci_pd_ops);
+		if (!ret)
+			ret = psci_set_suspend_mode_osi(true);
+		if (ret)
+			pr_warn("CPU%d: Error setting PSCI OSI mode\n", cpu);
+	}
+
 	return 0;
 
 free_mem:
@@ -330,15 +386,17 @@ int psci_cpu_init_idle(unsigned int cpu)
 static int psci_suspend_finisher(unsigned long index)
 {
 	u32 *state = __this_cpu_read(psci_power_state);
+	u32 ext_state = psci_get_composite_state_id(state[index - 1]);
 
-	return psci_ops.cpu_suspend(state[index - 1],
-				    virt_to_phys(cpu_resume));
+	return psci_ops.cpu_suspend(ext_state, virt_to_phys(cpu_resume));
 }
 
 int psci_cpu_suspend_enter(unsigned long index)
 {
 	int ret;
 	u32 *state = __this_cpu_read(psci_power_state);
+	u32 ext_state = psci_get_composite_state_id(state[index - 1]);
+
 	/*
 	 * idle state index 0 corresponds to wfi, should never be called
 	 * from the cpu_suspend operations
@@ -347,10 +405,16 @@ int psci_cpu_suspend_enter(unsigned long index)
 		return -EINVAL;
 
 	if (!psci_power_state_loses_context(state[index - 1]))
-		ret = psci_ops.cpu_suspend(state[index - 1], 0);
+		ret = psci_ops.cpu_suspend(ext_state, 0);
 	else
 		ret = cpu_suspend(index, psci_suspend_finisher);
 
+	/*
+	 * Clear the CPU's cluster states, we start afresh after coming
+	 * out of idle.
+	 */
+	psci_reset_composite_state_id();
+
 	return ret;
 }
 
-- 
2.7.4

[PATCH 12/14] drivers: firmware: psci: Support cluster idle states for OS-Initiated

[Lina Iyer]

PSCI OS initiated firmware may allow Linux to determine the state of the
CPU cluster and the cluster at coherency level to enter idle states when
there are no active CPUs. Since Linux has a better idea of the QoS and
the wakeup pattern of the CPUs, the cluster idle states may be better
determined by the OS instead of the firmware.

The last CPU entering idle in a cluster, is responsible for selecting
the state of the cluster. Only one CPU in a cluster may provide the
cluster idle state to the firmware. Similarly, the last CPU in the
system may provide the state of the coherency domain along with the
cluster and the CPU state IDs.

Utilize the CPU PM domain framework's helper functions to build up the
hierarchy of cluster topology using Generic PM domains. We provide
callbacks for domain power_on and power_off. By appending the state IDs
at each domain level in the -power_off() callbacks, we build up a
composite state ID that can be passed onto the firmware to idle the CPU,
the cluster and the coherency interface.

Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 drivers/firmware/psci.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 67 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
index 3920aba..01ec0d5 100644
--- a/drivers/firmware/psci.c
+++ b/drivers/firmware/psci.c
@@ -15,6 +15,7 @@
 
 #include <linux/arm-smccc.h>
 #include <linux/cpuidle.h>
+#include <linux/cpu_domains.h>
 #include <linux/errno.h>
 #include <linux/linkage.h>
 #include <linux/of.h>
@@ -53,6 +54,17 @@
  */
 static int resident_cpu = -1;
 static bool psci_has_osi_pd;
+static DEFINE_PER_CPU(u32, cluster_state_id);
+
+static inline u32 psci_get_composite_state_id(u32 cpu_state)
+{
+	return cpu_state | this_cpu_read(cluster_state_id);
+}
+
+static inline void psci_reset_composite_state_id(void)
+{
+	this_cpu_write(cluster_state_id, 0);
+}
 
 bool psci_tos_resident_on(int cpu)
 {
@@ -179,6 +191,8 @@ static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
 
 	fn = psci_function_id[PSCI_FN_CPU_ON];
 	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
+	/* Reset CPU cluster states */
+	psci_reset_composite_state_id();
 	return psci_to_linux_errno(err);
 }
 
@@ -250,6 +264,34 @@ static int __init psci_features(u32 psci_func_id)
 
 #ifdef CONFIG_CPU_IDLE
 static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
+static bool psci_suspend_mode_is_osi;
+
+static int psci_set_suspend_mode_osi(bool enable)
+{
+	int ret;
+	int mode;
+
+	if (enable && !psci_has_osi_pd)
+		return -ENODEV;
+
+	if (enable == psci_suspend_mode_is_osi)
+		return 0;
+
+	mode = enable ? PSCI_1_0_SUSPEND_MODE_OSI : PSCI_1_0_SUSPEND_MODE_PC;
+	ret = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE,
+			     mode, 0, 0);
+	if (!ret)
+		psci_suspend_mode_is_osi = enable;
+
+	return psci_to_linux_errno(ret);
+}
+
+static int psci_pd_power_off(u32 state_idx, u32 param,
+		const struct cpumask *mask)
+{
+	__this_cpu_add(cluster_state_id, param);
+	return 0;
+}
 
 static int psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
 {
@@ -304,6 +346,20 @@ static int psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
 	}
 	/* Idle states parsed correctly, initialize per-cpu pointer */
 	per_cpu(psci_power_state, cpu) = psci_states;
+
+	if (psci_has_osi_pd) {
+		int ret;
+		const struct cpu_pd_ops psci_pd_ops = {
+			.power_off = psci_pd_power_off,
+		};
+
+		ret = of_setup_cpu_pd_single(cpu, &psci_pd_ops);
+		if (!ret)
+			ret = psci_set_suspend_mode_osi(true);
+		if (ret)
+			pr_warn("CPU%d: Error setting PSCI OSI mode\n", cpu);
+	}
+
 	return 0;
 
 free_mem:
@@ -330,15 +386,17 @@ int psci_cpu_init_idle(unsigned int cpu)
 static int psci_suspend_finisher(unsigned long index)
 {
 	u32 *state = __this_cpu_read(psci_power_state);
+	u32 ext_state = psci_get_composite_state_id(state[index - 1]);
 
-	return psci_ops.cpu_suspend(state[index - 1],
-				    virt_to_phys(cpu_resume));
+	return psci_ops.cpu_suspend(ext_state, virt_to_phys(cpu_resume));
 }
 
 int psci_cpu_suspend_enter(unsigned long index)
 {
 	int ret;
 	u32 *state = __this_cpu_read(psci_power_state);
+	u32 ext_state = psci_get_composite_state_id(state[index - 1]);
+
 	/*
 	 * idle state index 0 corresponds to wfi, should never be called
 	 * from the cpu_suspend operations
@@ -347,10 +405,16 @@ int psci_cpu_suspend_enter(unsigned long index)
 		return -EINVAL;
 
 	if (!psci_power_state_loses_context(state[index - 1]))
-		ret = psci_ops.cpu_suspend(state[index - 1], 0);
+		ret = psci_ops.cpu_suspend(ext_state, 0);
 	else
 		ret = cpu_suspend(index, psci_suspend_finisher);
 
+	/*
+	 * Clear the CPU's cluster states, we start afresh after coming
+	 * out of idle.
+	 */
+	psci_reset_composite_state_id();
+
 	return ret;
 }
 
-- 
2.7.4

[PATCH 13/14] ARM64: dts: Add PSCI cpuidle support for MSM8916

[Lina Iyer]

Add device bindings for CPUs to suspend using PSCI as the enable-method.

Cc: <devicetree@vger.kernel.org>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 arch/arm64/boot/dts/qcom/msm8916.dtsi | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi b/arch/arm64/boot/dts/qcom/msm8916.dtsi
index 9681200..3029773 100644
--- a/arch/arm64/boot/dts/qcom/msm8916.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8916.dtsi
@@ -62,6 +62,8 @@
 			compatible = "arm,cortex-a53", "arm,armv8";
 			reg = <0x0>;
 			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+			cpu-idle-states = <&CPU_SPC>;
 		};
 
 		CPU1: cpu@1 {
@@ -69,6 +71,8 @@
 			compatible = "arm,cortex-a53", "arm,armv8";
 			reg = <0x1>;
 			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+			cpu-idle-states = <&CPU_SPC>;
 		};
 
 		CPU2: cpu@2 {
@@ -76,6 +80,8 @@
 			compatible = "arm,cortex-a53", "arm,armv8";
 			reg = <0x2>;
 			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+			cpu-idle-states = <&CPU_SPC>;
 		};
 
 		CPU3: cpu@3 {
@@ -83,12 +89,30 @@
 			compatible = "arm,cortex-a53", "arm,armv8";
 			reg = <0x3>;
 			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+			cpu-idle-states = <&CPU_SPC>;
 		};
 
 		L2_0: l2-cache {
 		      compatible = "cache";
 		      cache-level = <2>;
 		};
+
+		idle-states {
+			CPU_SPC: spc {
+				compatible = "arm,idle-state";
+				arm,psci-suspend-param = <0x40000002>;
+				entry-latency-us = <130>;
+				exit-latency-us = <150>;
+				min-residency-us = <2000>;
+				local-timer-stop;
+			};
+		};
+	};
+
+	psci {
+		compatible = "arm,psci-1.0";
+		method = "smc";
 	};
 
 	timer {
-- 
2.7.4

[PATCH 13/14] ARM64: dts: Add PSCI cpuidle support for MSM8916

[Lina Iyer]

Add device bindings for CPUs to suspend using PSCI as the enable-method.

Cc: <devicetree@vger.kernel.org>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 arch/arm64/boot/dts/qcom/msm8916.dtsi | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi b/arch/arm64/boot/dts/qcom/msm8916.dtsi
index 9681200..3029773 100644
--- a/arch/arm64/boot/dts/qcom/msm8916.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8916.dtsi
@@ -62,6 +62,8 @@
 			compatible = "arm,cortex-a53", "arm,armv8";
 			reg = <0x0>;
 			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+			cpu-idle-states = <&CPU_SPC>;
 		};
 
 		CPU1: cpu at 1 {
@@ -69,6 +71,8 @@
 			compatible = "arm,cortex-a53", "arm,armv8";
 			reg = <0x1>;
 			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+			cpu-idle-states = <&CPU_SPC>;
 		};
 
 		CPU2: cpu at 2 {
@@ -76,6 +80,8 @@
 			compatible = "arm,cortex-a53", "arm,armv8";
 			reg = <0x2>;
 			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+			cpu-idle-states = <&CPU_SPC>;
 		};
 
 		CPU3: cpu at 3 {
@@ -83,12 +89,30 @@
 			compatible = "arm,cortex-a53", "arm,armv8";
 			reg = <0x3>;
 			next-level-cache = <&L2_0>;
+			enable-method = "psci";
+			cpu-idle-states = <&CPU_SPC>;
 		};
 
 		L2_0: l2-cache {
 		      compatible = "cache";
 		      cache-level = <2>;
 		};
+
+		idle-states {
+			CPU_SPC: spc {
+				compatible = "arm,idle-state";
+				arm,psci-suspend-param = <0x40000002>;
+				entry-latency-us = <130>;
+				exit-latency-us = <150>;
+				min-residency-us = <2000>;
+				local-timer-stop;
+			};
+		};
+	};
+
+	psci {
+		compatible = "arm,psci-1.0";
+		method = "smc";
 	};
 
 	timer {
-- 
2.7.4

[PATCH 14/14] ARM64: dts: Define CPU power domain for MSM8916

[Lina Iyer]

Define power domain and the power states for the domain as defined by
the PSCI firmware. The 8916 firmware supports OS initiated method of
powering off the CPU clusters.

Cc: <devicetree@vger.kernel.org>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 arch/arm64/boot/dts/qcom/msm8916.dtsi | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi b/arch/arm64/boot/dts/qcom/msm8916.dtsi
index 3029773..208af00 100644
--- a/arch/arm64/boot/dts/qcom/msm8916.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8916.dtsi
@@ -64,6 +64,7 @@
 			next-level-cache = <&L2_0>;
 			enable-method = "psci";
 			cpu-idle-states = <&CPU_SPC>;
+			power-domains = <&CPU_PD>;
 		};
 
 		CPU1: cpu@1 {
@@ -73,6 +74,7 @@
 			next-level-cache = <&L2_0>;
 			enable-method = "psci";
 			cpu-idle-states = <&CPU_SPC>;
+			power-domains = <&CPU_PD>;
 		};
 
 		CPU2: cpu@2 {
@@ -82,6 +84,7 @@
 			next-level-cache = <&L2_0>;
 			enable-method = "psci";
 			cpu-idle-states = <&CPU_SPC>;
+			power-domains = <&CPU_PD>;
 		};
 
 		CPU3: cpu@3 {
@@ -91,6 +94,7 @@
 			next-level-cache = <&L2_0>;
 			enable-method = "psci";
 			cpu-idle-states = <&CPU_SPC>;
+			power-domains = <&CPU_PD>;
 		};
 
 		L2_0: l2-cache {
@@ -110,6 +114,27 @@
 		};
 	};
 
+	CPU_PD: cpu-pd@0 {
+		#power-domain-cells = <0>;
+		power-states = <&CLUSTER_RET>, <&CLUSTER_PWR_DWN>;
+	};
+
+	pd-power-states {
+		CLUSTER_RET: power-state@1 {
+			state-param = <0x1000010>;
+			entry-latency-us = <500>;
+			exit-latency-us = <500>;
+			residency-us = <2000>;
+		 };
+
+		CLUSTER_PWR_DWN: power-state@2 {
+			state-param = <0x1000030>;
+			entry-latency-us = <2000>;
+			exit-latency-us = <2000>;
+			residency-us = <6000>;
+		};
+	};
+
 	psci {
 		compatible = "arm,psci-1.0";
 		method = "smc";
-- 
2.7.4

[PATCH 14/14] ARM64: dts: Define CPU power domain for MSM8916

[Lina Iyer]

Define power domain and the power states for the domain as defined by
the PSCI firmware. The 8916 firmware supports OS initiated method of
powering off the CPU clusters.

Cc: <devicetree@vger.kernel.org>
Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
---
 arch/arm64/boot/dts/qcom/msm8916.dtsi | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi b/arch/arm64/boot/dts/qcom/msm8916.dtsi
index 3029773..208af00 100644
--- a/arch/arm64/boot/dts/qcom/msm8916.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8916.dtsi
@@ -64,6 +64,7 @@
 			next-level-cache = <&L2_0>;
 			enable-method = "psci";
 			cpu-idle-states = <&CPU_SPC>;
+			power-domains = <&CPU_PD>;
 		};
 
 		CPU1: cpu at 1 {
@@ -73,6 +74,7 @@
 			next-level-cache = <&L2_0>;
 			enable-method = "psci";
 			cpu-idle-states = <&CPU_SPC>;
+			power-domains = <&CPU_PD>;
 		};
 
 		CPU2: cpu at 2 {
@@ -82,6 +84,7 @@
 			next-level-cache = <&L2_0>;
 			enable-method = "psci";
 			cpu-idle-states = <&CPU_SPC>;
+			power-domains = <&CPU_PD>;
 		};
 
 		CPU3: cpu at 3 {
@@ -91,6 +94,7 @@
 			next-level-cache = <&L2_0>;
 			enable-method = "psci";
 			cpu-idle-states = <&CPU_SPC>;
+			power-domains = <&CPU_PD>;
 		};
 
 		L2_0: l2-cache {
@@ -110,6 +114,27 @@
 		};
 	};
 
+	CPU_PD: cpu-pd at 0 {
+		#power-domain-cells = <0>;
+		power-states = <&CLUSTER_RET>, <&CLUSTER_PWR_DWN>;
+	};
+
+	pd-power-states {
+		CLUSTER_RET: power-state at 1 {
+			state-param = <0x1000010>;
+			entry-latency-us = <500>;
+			exit-latency-us = <500>;
+			residency-us = <2000>;
+		 };
+
+		CLUSTER_PWR_DWN: power-state at 2 {
+			state-param = <0x1000030>;
+			entry-latency-us = <2000>;
+			exit-latency-us = <2000>;
+			residency-us = <6000>;
+		};
+	};
+
 	psci {
 		compatible = "arm,psci-1.0";
 		method = "smc";
-- 
2.7.4

Re: [PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Mark Rutland]

Hi,

On Wed, Jun 22, 2016 at 01:36:37PM -0600, Lina Iyer wrote:
> From: Axel Haslam <ahaslam+renesas-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
> 
> Update DT bindings to describe idle states of PM domains.
> 
> Cc: <devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
> Signed-off-by: Marc Titinger <mtitinger+renesas-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
> Signed-off-by: Lina Iyer <lina.iyer-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> [Lina: Added state properties, removed state names, wakeup-latency,
> added of_pm_genpd_init() API, pruned commit text]
> Signed-off-by: Ulf Hansson <ulf.hansson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> [Ulf: Moved around code to make it compile properly, rebased on top of multiple state support]
> ---
>  .../devicetree/bindings/power/power_domain.txt     | 70 ++++++++++++++++++++++
>  1 file changed, 70 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
> index 025b5e7..41e8dda 100644
> --- a/Documentation/devicetree/bindings/power/power_domain.txt
> +++ b/Documentation/devicetree/bindings/power/power_domain.txt
> @@ -29,6 +29,43 @@ Optional properties:
>     specified by this binding. More details about power domain specifier are
>     available in the next section.
>  
> +- power-states : A phandle of an idle-state that shall be soaked into a
> +                generic domain power state.

It's somewhat unfortunate that this gives us two possible locations for
idle state lists (under the /cpus node and in a pm-domains node),
especially as it's not clear what would happen were a DT to have both.

I would prefer that we extend the existing bindings such that states can
refer to the power domains which they affect.

> +==Power state==
> +
> +A PM domain power state describes an idle state of a domain and must be
> +have the following properties -
> +
> +	- entry-latency-us
> +		Usage: Not required if wakeup-latency-us is provided.
> +		Value type: <prop-encoded-array>
> +		Definition: u32 value representing worst case latency in
> +		microseconds required to enter the idle state.
> +		The exit-latency-us duration may be guaranteed
> +		only after entry-latency-us has passed.
> +
> +	- exit-latency-us
> +		Usage: Not required if wakeup-latency-us is provided.
> +		Value type: <prop-encoded-array>
> +		Definition: u32 value representing worst case latency
> +		in microseconds required to exit the idle state.

These are part of the existing idle state binding
(Documentation/devicetree/bindings/arm/idle-states.txt), and I would
prefer that we did not duplicate this nor come up with an independent
set of idle state bindings.

> +
> +	- residency-us:
> +		Usage: Optional
> +		Value type: <prop-encoded-array>
> +		Definition: A u32 value representing the time for which a
> +		domain must be idle in the state to reap power saving benefits
> +		of entering the state.

This is "min-residency-us" per the existing bindings.

> +
> +	- state-param:
> +		Usage: Optional
> +		Value type: <prop-encoded-array>
> +		Definition: A u32 value as defined by the state. May be used
> +		by the driver to hold state related u32 data. In the case of
> +		PSCI, an extended state-id for the domain may be encoded in
> +		this value.

This is "arm,psci-suspend-param", per the existing bindings.

Thanks,
Mark.
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[PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Mark Rutland]

Hi,

On Wed, Jun 22, 2016 at 01:36:37PM -0600, Lina Iyer wrote:
> From: Axel Haslam <ahaslam+renesas@baylibre.com>
> 
> Update DT bindings to describe idle states of PM domains.
> 
> Cc: <devicetree@vger.kernel.org>
> Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> [Lina: Added state properties, removed state names, wakeup-latency,
> added of_pm_genpd_init() API, pruned commit text]
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> [Ulf: Moved around code to make it compile properly, rebased on top of multiple state support]
> ---
>  .../devicetree/bindings/power/power_domain.txt     | 70 ++++++++++++++++++++++
>  1 file changed, 70 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
> index 025b5e7..41e8dda 100644
> --- a/Documentation/devicetree/bindings/power/power_domain.txt
> +++ b/Documentation/devicetree/bindings/power/power_domain.txt
> @@ -29,6 +29,43 @@ Optional properties:
>     specified by this binding. More details about power domain specifier are
>     available in the next section.
>  
> +- power-states : A phandle of an idle-state that shall be soaked into a
> +                generic domain power state.

It's somewhat unfortunate that this gives us two possible locations for
idle state lists (under the /cpus node and in a pm-domains node),
especially as it's not clear what would happen were a DT to have both.

I would prefer that we extend the existing bindings such that states can
refer to the power domains which they affect.

> +==Power state==
> +
> +A PM domain power state describes an idle state of a domain and must be
> +have the following properties -
> +
> +	- entry-latency-us
> +		Usage: Not required if wakeup-latency-us is provided.
> +		Value type: <prop-encoded-array>
> +		Definition: u32 value representing worst case latency in
> +		microseconds required to enter the idle state.
> +		The exit-latency-us duration may be guaranteed
> +		only after entry-latency-us has passed.
> +
> +	- exit-latency-us
> +		Usage: Not required if wakeup-latency-us is provided.
> +		Value type: <prop-encoded-array>
> +		Definition: u32 value representing worst case latency
> +		in microseconds required to exit the idle state.

These are part of the existing idle state binding
(Documentation/devicetree/bindings/arm/idle-states.txt), and I would
prefer that we did not duplicate this nor come up with an independent
set of idle state bindings.

> +
> +	- residency-us:
> +		Usage: Optional
> +		Value type: <prop-encoded-array>
> +		Definition: A u32 value representing the time for which a
> +		domain must be idle in the state to reap power saving benefits
> +		of entering the state.

This is "min-residency-us" per the existing bindings.

> +
> +	- state-param:
> +		Usage: Optional
> +		Value type: <prop-encoded-array>
> +		Definition: A u32 value as defined by the state. May be used
> +		by the driver to hold state related u32 data. In the case of
> +		PSCI, an extended state-id for the domain may be encoded in
> +		this value.

This is "arm,psci-suspend-param", per the existing bindings.

Thanks,
Mark.

Re: [PATCH 01/14] PM / Domains: Allow domain power states to be read from DT

[Mark Rutland]

On Wed, Jun 22, 2016 at 01:36:36PM -0600, Lina Iyer wrote:
> From: Axel Haslam <ahaslam+renesas@baylibre.com>
> 
> This patch allows domains to define idle states in the DT. SoC's can
> define domain idle states in DT using the "power-states" property of the
> domain provider. Calling of_pm_genpd_init() will  read the idle states
> and initialize the genpd for the domain.
> 
> In addition to the entry and exit latency for idle state, also add
> residency and state-param properties. A domain idling in a state is only
> power effecient if it stays idle for a certain period in that state. The
> residency provides this minimum time for the idle state to provide power
> benefits. The state-param is a state specific u32 value that the
> platform may use for that idle state.
> 
> Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> [Lina: Added state properties, removed state names, wakeup-latency,
> added of_pm_genpd_init() API, pruned commit text]
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> [Ulf: Moved around code to make it compile properly, rebased on top of multiple
> state support,changed to use pm_genpd_init()]
> ---
>  drivers/base/power/domain.c | 84 ++++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/pm_domain.h   |  3 ++
>  2 files changed, 86 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index a1f2aff..62ffabd 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1253,6 +1253,82 @@ out:
>  }
>  EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
>  
> +static int genpd_of_get_power_state(struct genpd_power_state *genpd_state,
> +				    struct device_node *state_node)
> +{
> +	int err = 0;
> +	u32 latency;
> +	u32 residency;
> +	u32 param;
> +	u32 entry_latency, exit_latency;
> +
> +	err = of_property_read_u32(state_node, "entry-latency-us",
> +				   &entry_latency);
> +	if (err) {
> +		pr_debug(" * %s missing entry-latency-us property\n",
> +			 state_node->full_name);
> +		return -EINVAL;
> +	}
> +
> +	err = of_property_read_u32(state_node, "exit-latency-us",
> +				   &exit_latency);
> +	if (err) {
> +		pr_debug(" * %s missing exit-latency-us property\n",
> +			 state_node->full_name);
> +		return -EINVAL;
> +	}
> +
> +	err = of_property_read_u32(state_node, "residency-us", &residency);
> +	if (!err)
> +		genpd_state->residency_ns = 1000 * residency;
> +
> +	err = of_property_read_u32(state_node, "state-param", &param);
> +	if (!err)
> +		genpd_state->param = param;
> +
> +	latency = entry_latency + exit_latency;
> +	genpd_state->power_on_latency_ns = 1000 * latency;
> +	genpd_state->power_off_latency_ns = 1000 * entry_latency;
> +
> +	return 0;
> +}

As with the binding, I would very much prefer that this were unfiied
with the existing idle state parsing. I'm not keen on having two
arbitrarily different idle state binidngs and parsers.

Thanks,
Mark.

[PATCH 01/14] PM / Domains: Allow domain power states to be read from DT

[Mark Rutland]

On Wed, Jun 22, 2016 at 01:36:36PM -0600, Lina Iyer wrote:
> From: Axel Haslam <ahaslam+renesas@baylibre.com>
> 
> This patch allows domains to define idle states in the DT. SoC's can
> define domain idle states in DT using the "power-states" property of the
> domain provider. Calling of_pm_genpd_init() will  read the idle states
> and initialize the genpd for the domain.
> 
> In addition to the entry and exit latency for idle state, also add
> residency and state-param properties. A domain idling in a state is only
> power effecient if it stays idle for a certain period in that state. The
> residency provides this minimum time for the idle state to provide power
> benefits. The state-param is a state specific u32 value that the
> platform may use for that idle state.
> 
> Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> [Lina: Added state properties, removed state names, wakeup-latency,
> added of_pm_genpd_init() API, pruned commit text]
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> [Ulf: Moved around code to make it compile properly, rebased on top of multiple
> state support,changed to use pm_genpd_init()]
> ---
>  drivers/base/power/domain.c | 84 ++++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/pm_domain.h   |  3 ++
>  2 files changed, 86 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index a1f2aff..62ffabd 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -1253,6 +1253,82 @@ out:
>  }
>  EXPORT_SYMBOL_GPL(pm_genpd_remove_subdomain);
>  
> +static int genpd_of_get_power_state(struct genpd_power_state *genpd_state,
> +				    struct device_node *state_node)
> +{
> +	int err = 0;
> +	u32 latency;
> +	u32 residency;
> +	u32 param;
> +	u32 entry_latency, exit_latency;
> +
> +	err = of_property_read_u32(state_node, "entry-latency-us",
> +				   &entry_latency);
> +	if (err) {
> +		pr_debug(" * %s missing entry-latency-us property\n",
> +			 state_node->full_name);
> +		return -EINVAL;
> +	}
> +
> +	err = of_property_read_u32(state_node, "exit-latency-us",
> +				   &exit_latency);
> +	if (err) {
> +		pr_debug(" * %s missing exit-latency-us property\n",
> +			 state_node->full_name);
> +		return -EINVAL;
> +	}
> +
> +	err = of_property_read_u32(state_node, "residency-us", &residency);
> +	if (!err)
> +		genpd_state->residency_ns = 1000 * residency;
> +
> +	err = of_property_read_u32(state_node, "state-param", &param);
> +	if (!err)
> +		genpd_state->param = param;
> +
> +	latency = entry_latency + exit_latency;
> +	genpd_state->power_on_latency_ns = 1000 * latency;
> +	genpd_state->power_off_latency_ns = 1000 * entry_latency;
> +
> +	return 0;
> +}

As with the binding, I would very much prefer that this were unfiied
with the existing idle state parsing. I'm not keen on having two
arbitrarily different idle state binidngs and parsers.

Thanks,
Mark.

Re: [PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Lina Iyer]

Hi Mark,

On Thu, Jun 23 2016 at 11:35 -0600, Mark Rutland wrote:
>Hi,
>
>On Wed, Jun 22, 2016 at 01:36:37PM -0600, Lina Iyer wrote:
>> From: Axel Haslam <ahaslam+renesas@baylibre.com>
>>
>> Update DT bindings to describe idle states of PM domains.
>>
>> Cc: <devicetree@vger.kernel.org>
>> Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
>> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>> [Lina: Added state properties, removed state names, wakeup-latency,
>> added of_pm_genpd_init() API, pruned commit text]
>> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>> [Ulf: Moved around code to make it compile properly, rebased on top of multiple state support]
>> ---
>>  .../devicetree/bindings/power/power_domain.txt     | 70 ++++++++++++++++++++++
>>  1 file changed, 70 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
>> index 025b5e7..41e8dda 100644
>> --- a/Documentation/devicetree/bindings/power/power_domain.txt
>> +++ b/Documentation/devicetree/bindings/power/power_domain.txt
>> @@ -29,6 +29,43 @@ Optional properties:
>>     specified by this binding. More details about power domain specifier are
>>     available in the next section.
>>
>> +- power-states : A phandle of an idle-state that shall be soaked into a
>> +                generic domain power state.
>
>It's somewhat unfortunate that this gives us two possible locations for
>idle state lists (under the /cpus node and in a pm-domains node),
>especially as it's not clear what would happen were a DT to have both.
>
>I would prefer that we extend the existing bindings such that states can
>refer to the power domains which they affect.
>
I agree. The CPU idle states have become defined to be specific to CPUs.
PM Domain idle states are generic for any type of domain. I am hoping at
some point, we could converge and use the same idle state, but that
would mean changing the CPU idle states to make it generic. At some
point, during my development, I did use the arm,idle-state for domains
as well, but the binding definitions were too restrictive for a generic
PM domain.

I would be willing to make the change to CPU idle states to make it
generic and then we could just reference domain and CPU idle states
using the same bindings. Are we okay with that, specifically,
arm,psci-suspend-param? This binding is very restrictive in its
description. What we pass to the platform driver upon choosing a domain
state is very platform specific and therefore has to be generic in its
description.

Thanks,
Lina

>> +==Power state==
>> +
>> +A PM domain power state describes an idle state of a domain and must be
>> +have the following properties -
>> +
>> +	- entry-latency-us
>> +		Usage: Not required if wakeup-latency-us is provided.
>> +		Value type: <prop-encoded-array>
>> +		Definition: u32 value representing worst case latency in
>> +		microseconds required to enter the idle state.
>> +		The exit-latency-us duration may be guaranteed
>> +		only after entry-latency-us has passed.
>> +
>> +	- exit-latency-us
>> +		Usage: Not required if wakeup-latency-us is provided.
>> +		Value type: <prop-encoded-array>
>> +		Definition: u32 value representing worst case latency
>> +		in microseconds required to exit the idle state.
>
>These are part of the existing idle state binding
>(Documentation/devicetree/bindings/arm/idle-states.txt), and I would
>prefer that we did not duplicate this nor come up with an independent
>set of idle state bindings.
>
>> +
>> +	- residency-us:
>> +		Usage: Optional
>> +		Value type: <prop-encoded-array>
>> +		Definition: A u32 value representing the time for which a
>> +		domain must be idle in the state to reap power saving benefits
>> +		of entering the state.
>
>This is "min-residency-us" per the existing bindings.
>
>> +
>> +	- state-param:
>> +		Usage: Optional
>> +		Value type: <prop-encoded-array>
>> +		Definition: A u32 value as defined by the state. May be used
>> +		by the driver to hold state related u32 data. In the case of
>> +		PSCI, an extended state-id for the domain may be encoded in
>> +		this value.
>
>This is "arm,psci-suspend-param", per the existing bindings.
>
>Thanks,
>Mark.

[PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Lina Iyer]

Hi Mark,

On Thu, Jun 23 2016 at 11:35 -0600, Mark Rutland wrote:
>Hi,
>
>On Wed, Jun 22, 2016 at 01:36:37PM -0600, Lina Iyer wrote:
>> From: Axel Haslam <ahaslam+renesas@baylibre.com>
>>
>> Update DT bindings to describe idle states of PM domains.
>>
>> Cc: <devicetree@vger.kernel.org>
>> Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
>> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>> [Lina: Added state properties, removed state names, wakeup-latency,
>> added of_pm_genpd_init() API, pruned commit text]
>> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>> [Ulf: Moved around code to make it compile properly, rebased on top of multiple state support]
>> ---
>>  .../devicetree/bindings/power/power_domain.txt     | 70 ++++++++++++++++++++++
>>  1 file changed, 70 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
>> index 025b5e7..41e8dda 100644
>> --- a/Documentation/devicetree/bindings/power/power_domain.txt
>> +++ b/Documentation/devicetree/bindings/power/power_domain.txt
>> @@ -29,6 +29,43 @@ Optional properties:
>>     specified by this binding. More details about power domain specifier are
>>     available in the next section.
>>
>> +- power-states : A phandle of an idle-state that shall be soaked into a
>> +                generic domain power state.
>
>It's somewhat unfortunate that this gives us two possible locations for
>idle state lists (under the /cpus node and in a pm-domains node),
>especially as it's not clear what would happen were a DT to have both.
>
>I would prefer that we extend the existing bindings such that states can
>refer to the power domains which they affect.
>
I agree. The CPU idle states have become defined to be specific to CPUs.
PM Domain idle states are generic for any type of domain. I am hoping at
some point, we could converge and use the same idle state, but that
would mean changing the CPU idle states to make it generic. At some
point, during my development, I did use the arm,idle-state for domains
as well, but the binding definitions were too restrictive for a generic
PM domain.

I would be willing to make the change to CPU idle states to make it
generic and then we could just reference domain and CPU idle states
using the same bindings. Are we okay with that, specifically,
arm,psci-suspend-param? This binding is very restrictive in its
description. What we pass to the platform driver upon choosing a domain
state is very platform specific and therefore has to be generic in its
description.

Thanks,
Lina

>> +==Power state==
>> +
>> +A PM domain power state describes an idle state of a domain and must be
>> +have the following properties -
>> +
>> +	- entry-latency-us
>> +		Usage: Not required if wakeup-latency-us is provided.
>> +		Value type: <prop-encoded-array>
>> +		Definition: u32 value representing worst case latency in
>> +		microseconds required to enter the idle state.
>> +		The exit-latency-us duration may be guaranteed
>> +		only after entry-latency-us has passed.
>> +
>> +	- exit-latency-us
>> +		Usage: Not required if wakeup-latency-us is provided.
>> +		Value type: <prop-encoded-array>
>> +		Definition: u32 value representing worst case latency
>> +		in microseconds required to exit the idle state.
>
>These are part of the existing idle state binding
>(Documentation/devicetree/bindings/arm/idle-states.txt), and I would
>prefer that we did not duplicate this nor come up with an independent
>set of idle state bindings.
>
>> +
>> +	- residency-us:
>> +		Usage: Optional
>> +		Value type: <prop-encoded-array>
>> +		Definition: A u32 value representing the time for which a
>> +		domain must be idle in the state to reap power saving benefits
>> +		of entering the state.
>
>This is "min-residency-us" per the existing bindings.
>
>> +
>> +	- state-param:
>> +		Usage: Optional
>> +		Value type: <prop-encoded-array>
>> +		Definition: A u32 value as defined by the state. May be used
>> +		by the driver to hold state related u32 data. In the case of
>> +		PSCI, an extended state-id for the domain may be encoded in
>> +		this value.
>
>This is "arm,psci-suspend-param", per the existing bindings.
>
>Thanks,
>Mark.

Re: [PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Mark Rutland]

On Thu, Jun 23, 2016 at 12:04:51PM -0600, Lina Iyer wrote:
> Hi Mark,
> 
> On Thu, Jun 23 2016 at 11:35 -0600, Mark Rutland wrote:
> >Hi,
> >
> >On Wed, Jun 22, 2016 at 01:36:37PM -0600, Lina Iyer wrote:
> >>From: Axel Haslam <ahaslam+renesas-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
> >>
> >>Update DT bindings to describe idle states of PM domains.
> >>
> >>Cc: <devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
> >>Signed-off-by: Marc Titinger <mtitinger+renesas-rdvid1DuHRBWk0Htik3J/w@public.gmane.org>
> >>Signed-off-by: Lina Iyer <lina.iyer-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> >>[Lina: Added state properties, removed state names, wakeup-latency,
> >>added of_pm_genpd_init() API, pruned commit text]
> >>Signed-off-by: Ulf Hansson <ulf.hansson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> >>[Ulf: Moved around code to make it compile properly, rebased on top of multiple state support]
> >>---
> >> .../devicetree/bindings/power/power_domain.txt     | 70 ++++++++++++++++++++++
> >> 1 file changed, 70 insertions(+)
> >>
> >>diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
> >>index 025b5e7..41e8dda 100644
> >>--- a/Documentation/devicetree/bindings/power/power_domain.txt
> >>+++ b/Documentation/devicetree/bindings/power/power_domain.txt
> >>@@ -29,6 +29,43 @@ Optional properties:
> >>    specified by this binding. More details about power domain specifier are
> >>    available in the next section.
> >>
> >>+- power-states : A phandle of an idle-state that shall be soaked into a
> >>+                generic domain power state.
> >
> >It's somewhat unfortunate that this gives us two possible locations for
> >idle state lists (under the /cpus node and in a pm-domains node),
> >especially as it's not clear what would happen were a DT to have both.
> >
> >I would prefer that we extend the existing bindings such that states can
> >refer to the power domains which they affect.
> >
> I agree. The CPU idle states have become defined to be specific to CPUs.
> PM Domain idle states are generic for any type of domain. I am hoping at
> some point, we could converge and use the same idle state, but that
> would mean changing the CPU idle states to make it generic.

Outside of CPU idling, I don't fully understand how this will be used,
so it's not clear to me what would need to be made generic. Apologies
for my ignorance there.

> At some point, during my development, I did use the arm,idle-state for
> domains as well, but the binding definitions were too restrictive for
> a generic PM domain.
> 
> I would be willing to make the change to CPU idle states to make it
> generic and then we could just reference domain and CPU idle states
> using the same bindings. Are we okay with that, specifically,
> arm,psci-suspend-param? This binding is very restrictive in its
> description. What we pass to the platform driver upon choosing a domain
> state is very platform specific and therefore has to be generic in its
> description.

I was suggesting that for PSCI we should consistently us
arm,psci-suspend-param, not that this should be used for all power
domain state data.

I imagine that mechanisms for powering down power domains will have
varied requirements on data they require (and may require more than can
be encoded in a u32), and I don't think it's best to try to force a
single representation in the DT for that. It would be better to allow
them to define the properties which they require.

Thanks,
Mark.
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[PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Mark Rutland]

On Thu, Jun 23, 2016 at 12:04:51PM -0600, Lina Iyer wrote:
> Hi Mark,
> 
> On Thu, Jun 23 2016 at 11:35 -0600, Mark Rutland wrote:
> >Hi,
> >
> >On Wed, Jun 22, 2016 at 01:36:37PM -0600, Lina Iyer wrote:
> >>From: Axel Haslam <ahaslam+renesas@baylibre.com>
> >>
> >>Update DT bindings to describe idle states of PM domains.
> >>
> >>Cc: <devicetree@vger.kernel.org>
> >>Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
> >>Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> >>[Lina: Added state properties, removed state names, wakeup-latency,
> >>added of_pm_genpd_init() API, pruned commit text]
> >>Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> >>[Ulf: Moved around code to make it compile properly, rebased on top of multiple state support]
> >>---
> >> .../devicetree/bindings/power/power_domain.txt     | 70 ++++++++++++++++++++++
> >> 1 file changed, 70 insertions(+)
> >>
> >>diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
> >>index 025b5e7..41e8dda 100644
> >>--- a/Documentation/devicetree/bindings/power/power_domain.txt
> >>+++ b/Documentation/devicetree/bindings/power/power_domain.txt
> >>@@ -29,6 +29,43 @@ Optional properties:
> >>    specified by this binding. More details about power domain specifier are
> >>    available in the next section.
> >>
> >>+- power-states : A phandle of an idle-state that shall be soaked into a
> >>+                generic domain power state.
> >
> >It's somewhat unfortunate that this gives us two possible locations for
> >idle state lists (under the /cpus node and in a pm-domains node),
> >especially as it's not clear what would happen were a DT to have both.
> >
> >I would prefer that we extend the existing bindings such that states can
> >refer to the power domains which they affect.
> >
> I agree. The CPU idle states have become defined to be specific to CPUs.
> PM Domain idle states are generic for any type of domain. I am hoping at
> some point, we could converge and use the same idle state, but that
> would mean changing the CPU idle states to make it generic.

Outside of CPU idling, I don't fully understand how this will be used,
so it's not clear to me what would need to be made generic. Apologies
for my ignorance there.

> At some point, during my development, I did use the arm,idle-state for
> domains as well, but the binding definitions were too restrictive for
> a generic PM domain.
> 
> I would be willing to make the change to CPU idle states to make it
> generic and then we could just reference domain and CPU idle states
> using the same bindings. Are we okay with that, specifically,
> arm,psci-suspend-param? This binding is very restrictive in its
> description. What we pass to the platform driver upon choosing a domain
> state is very platform specific and therefore has to be generic in its
> description.

I was suggesting that for PSCI we should consistently us
arm,psci-suspend-param, not that this should be used for all power
domain state data.

I imagine that mechanisms for powering down power domains will have
varied requirements on data they require (and may require more than can
be encoded in a u32), and I don't think it's best to try to force a
single representation in the DT for that. It would be better to allow
them to define the properties which they require.

Thanks,
Mark.

Re: [PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Lina Iyer]

On Thu, Jun 23 2016 at 12:19 -0600, Mark Rutland wrote:
>On Thu, Jun 23, 2016 at 12:04:51PM -0600, Lina Iyer wrote:
>> Hi Mark,
>>
>> On Thu, Jun 23 2016 at 11:35 -0600, Mark Rutland wrote:
>> >Hi,
>> >
>> >On Wed, Jun 22, 2016 at 01:36:37PM -0600, Lina Iyer wrote:
>> >>From: Axel Haslam <ahaslam+renesas@baylibre.com>
>> >>
>> >>Update DT bindings to describe idle states of PM domains.
>> >>
>> >>Cc: <devicetree@vger.kernel.org>
>> >>Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
>> >>Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>> >>[Lina: Added state properties, removed state names, wakeup-latency,
>> >>added of_pm_genpd_init() API, pruned commit text]
>> >>Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>> >>[Ulf: Moved around code to make it compile properly, rebased on top of multiple state support]
>> >>---
>> >> .../devicetree/bindings/power/power_domain.txt     | 70 ++++++++++++++++++++++
>> >> 1 file changed, 70 insertions(+)
>> >>
>> >>diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
>> >>index 025b5e7..41e8dda 100644
>> >>--- a/Documentation/devicetree/bindings/power/power_domain.txt
>> >>+++ b/Documentation/devicetree/bindings/power/power_domain.txt
>> >>@@ -29,6 +29,43 @@ Optional properties:
>> >>    specified by this binding. More details about power domain specifier are
>> >>    available in the next section.
>> >>
>> >>+- power-states : A phandle of an idle-state that shall be soaked into a
>> >>+                generic domain power state.
>> >
>> >It's somewhat unfortunate that this gives us two possible locations for
>> >idle state lists (under the /cpus node and in a pm-domains node),
>> >especially as it's not clear what would happen were a DT to have both.
>> >
>> >I would prefer that we extend the existing bindings such that states can
>> >refer to the power domains which they affect.
>> >
>> I agree. The CPU idle states have become defined to be specific to CPUs.
>> PM Domain idle states are generic for any type of domain. I am hoping at
>> some point, we could converge and use the same idle state, but that
>> would mean changing the CPU idle states to make it generic.
>
>Outside of CPU idling, I don't fully understand how this will be used,
>so it's not clear to me what would need to be made generic. Apologies
>for my ignorance there.
>
There may be non-PSCI ARM v7 CPU domains that may have domain controller
drivers in the kernel. They would not hook into the ARM PSCI frameworks.
It is still cpuidle though.

>> At some point, during my development, I did use the arm,idle-state for
>> domains as well, but the binding definitions were too restrictive for
>> a generic PM domain.
>>
>> I would be willing to make the change to CPU idle states to make it
>> generic and then we could just reference domain and CPU idle states
>> using the same bindings. Are we okay with that, specifically,
>> arm,psci-suspend-param? This binding is very restrictive in its
>> description. What we pass to the platform driver upon choosing a domain
>> state is very platform specific and therefore has to be generic in its
>> description.
>
>I was suggesting that for PSCI we should consistently us
>arm,psci-suspend-param, not that this should be used for all power
>domain state data.
>
>I imagine that mechanisms for powering down power domains will have
>varied requirements on data they require (and may require more than can
>be encoded in a u32), and I don't think it's best to try to force a
>single representation in the DT for that. It would be better to allow
>them to define the properties which they require.
>
The only way to do that is to push the DT parsing to the platform
drivers. In the case of CPU domains controlled by PSCI, we could use the
arm,idle-states but any other generic domain, may need to define their
own bindings and fill up the domain states before initiailizing the domain.

While this approach pushes the onus on to the platform code, I am fine
with it. Is that what you were thinking too?

Thanks,
Lina

[PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Lina Iyer]

On Thu, Jun 23 2016 at 12:19 -0600, Mark Rutland wrote:
>On Thu, Jun 23, 2016 at 12:04:51PM -0600, Lina Iyer wrote:
>> Hi Mark,
>>
>> On Thu, Jun 23 2016 at 11:35 -0600, Mark Rutland wrote:
>> >Hi,
>> >
>> >On Wed, Jun 22, 2016 at 01:36:37PM -0600, Lina Iyer wrote:
>> >>From: Axel Haslam <ahaslam+renesas@baylibre.com>
>> >>
>> >>Update DT bindings to describe idle states of PM domains.
>> >>
>> >>Cc: <devicetree@vger.kernel.org>
>> >>Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
>> >>Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>> >>[Lina: Added state properties, removed state names, wakeup-latency,
>> >>added of_pm_genpd_init() API, pruned commit text]
>> >>Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>> >>[Ulf: Moved around code to make it compile properly, rebased on top of multiple state support]
>> >>---
>> >> .../devicetree/bindings/power/power_domain.txt     | 70 ++++++++++++++++++++++
>> >> 1 file changed, 70 insertions(+)
>> >>
>> >>diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
>> >>index 025b5e7..41e8dda 100644
>> >>--- a/Documentation/devicetree/bindings/power/power_domain.txt
>> >>+++ b/Documentation/devicetree/bindings/power/power_domain.txt
>> >>@@ -29,6 +29,43 @@ Optional properties:
>> >>    specified by this binding. More details about power domain specifier are
>> >>    available in the next section.
>> >>
>> >>+- power-states : A phandle of an idle-state that shall be soaked into a
>> >>+                generic domain power state.
>> >
>> >It's somewhat unfortunate that this gives us two possible locations for
>> >idle state lists (under the /cpus node and in a pm-domains node),
>> >especially as it's not clear what would happen were a DT to have both.
>> >
>> >I would prefer that we extend the existing bindings such that states can
>> >refer to the power domains which they affect.
>> >
>> I agree. The CPU idle states have become defined to be specific to CPUs.
>> PM Domain idle states are generic for any type of domain. I am hoping at
>> some point, we could converge and use the same idle state, but that
>> would mean changing the CPU idle states to make it generic.
>
>Outside of CPU idling, I don't fully understand how this will be used,
>so it's not clear to me what would need to be made generic. Apologies
>for my ignorance there.
>
There may be non-PSCI ARM v7 CPU domains that may have domain controller
drivers in the kernel. They would not hook into the ARM PSCI frameworks.
It is still cpuidle though.

>> At some point, during my development, I did use the arm,idle-state for
>> domains as well, but the binding definitions were too restrictive for
>> a generic PM domain.
>>
>> I would be willing to make the change to CPU idle states to make it
>> generic and then we could just reference domain and CPU idle states
>> using the same bindings. Are we okay with that, specifically,
>> arm,psci-suspend-param? This binding is very restrictive in its
>> description. What we pass to the platform driver upon choosing a domain
>> state is very platform specific and therefore has to be generic in its
>> description.
>
>I was suggesting that for PSCI we should consistently us
>arm,psci-suspend-param, not that this should be used for all power
>domain state data.
>
>I imagine that mechanisms for powering down power domains will have
>varied requirements on data they require (and may require more than can
>be encoded in a u32), and I don't think it's best to try to force a
>single representation in the DT for that. It would be better to allow
>them to define the properties which they require.
>
The only way to do that is to push the DT parsing to the platform
drivers. In the case of CPU domains controlled by PSCI, we could use the
arm,idle-states but any other generic domain, may need to define their
own bindings and fill up the domain states before initiailizing the domain.

While this approach pushes the onus on to the platform code, I am fine
with it. Is that what you were thinking too?

Thanks,
Lina

Re: [PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Vikas Sajjan]

Hi Lina,

On Thu, Jun 23, 2016 at 1:06 AM, Lina Iyer <lina.iyer@linaro.org> wrote:
> PSCI firmware v1.0 onwards may support 2 different modes for
> CPU_SUSPEND. Platform coordinated mode is the default and every firmware
> should support it. OS Initiated mode is optional for the firmware to
> implement and allow Linux to make an better decision on the state of
> the CPU cluster heirarchy.
>
> With the kernel capable of deciding the state for CPU cluster and
> coherency domains, the OS Initiated mode may now be used by the kernel,
> provided the firmware supports it. SET_SUSPEND_MODE is a PSCI function
> available on v1.0 onwards and can be used to set the mode in the
> firmware.
>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> [Ulf: Rebased on 4.7 rc1]
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>  drivers/firmware/psci.c   | 22 +++++++++++++++++++++-
>  include/uapi/linux/psci.h |  5 +++++
>  2 files changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
> index 03e0458..3920aba 100644
> --- a/drivers/firmware/psci.c
> +++ b/drivers/firmware/psci.c
> @@ -52,6 +52,7 @@
>   * require cooperation with a Trusted OS driver.
>   */
>  static int resident_cpu = -1;
> +static bool psci_has_osi_pd;
>
>  bool psci_tos_resident_on(int cpu)
>  {
> @@ -563,10 +564,29 @@ out_put_node:
>         return err;
>  }
>
> +static int __init psci_1_0_init(struct device_node *np)
> +{
> +       int ret;
> +
> +       ret = psci_0_2_init(np);
> +       if (ret)
> +               return ret;
> +
> +       /* Check if PSCI OSI mode is available */
> +       ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
> +       if (ret & PSCI_1_0_OS_INITIATED) {
> +               ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
> +               if (!ret)
> +                       psci_has_osi_pd = true;

IMHO, its better to have this done in psci_init_cpu_suspend() itself
for 2 reasons

a] psci_init_cpu_suspend() already calls
psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND])
b] by moving this in psci_init_cpu_suspend() we make this support
available even for ACPI platforms, since psci_acpi_init() calls
psci_probe() and this calls  psci_init_cpu_suspend() for
PSCI_VERSION_MAJOR(ver) >= 1

I even posted a patch [1] yesterday, without being aware of your
patchset for the same.

[1] http://www.spinics.net/lists/arm-kernel/msg513682.html


> +       }
> +
> +       return 0;
> +}
> +
>  static const struct of_device_id psci_of_match[] __initconst = {
>         { .compatible = "arm,psci",     .data = psci_0_1_init},
>         { .compatible = "arm,psci-0.2", .data = psci_0_2_init},
> -       { .compatible = "arm,psci-1.0", .data = psci_0_2_init},
> +       { .compatible = "arm,psci-1.0", .data = psci_1_0_init},
>         {},
>  };
>
> diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
> index 3d7a0fc..7dd778e 100644
> --- a/include/uapi/linux/psci.h
> +++ b/include/uapi/linux/psci.h
> @@ -48,6 +48,7 @@
>
>  #define PSCI_1_0_FN_PSCI_FEATURES              PSCI_0_2_FN(10)
>  #define PSCI_1_0_FN_SYSTEM_SUSPEND             PSCI_0_2_FN(14)
> +#define PSCI_1_0_FN_SET_SUSPEND_MODE           PSCI_0_2_FN(15)
>
>  #define PSCI_1_0_FN64_SYSTEM_SUSPEND           PSCI_0_2_FN64(14)
>
> @@ -93,6 +94,10 @@
>  #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK  \
>                         (0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)
>
> +#define PSCI_1_0_OS_INITIATED                  BIT(0)
> +#define PSCI_1_0_SUSPEND_MODE_PC               0
> +#define PSCI_1_0_SUSPEND_MODE_OSI              1
> +
>  /* PSCI return values (inclusive of all PSCI versions) */
>  #define PSCI_RET_SUCCESS                       0
>  #define PSCI_RET_NOT_SUPPORTED                 -1
> --
> 2.7.4
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Vikas Sajjan]

Hi Lina,

On Thu, Jun 23, 2016 at 1:06 AM, Lina Iyer <lina.iyer@linaro.org> wrote:
> PSCI firmware v1.0 onwards may support 2 different modes for
> CPU_SUSPEND. Platform coordinated mode is the default and every firmware
> should support it. OS Initiated mode is optional for the firmware to
> implement and allow Linux to make an better decision on the state of
> the CPU cluster heirarchy.
>
> With the kernel capable of deciding the state for CPU cluster and
> coherency domains, the OS Initiated mode may now be used by the kernel,
> provided the firmware supports it. SET_SUSPEND_MODE is a PSCI function
> available on v1.0 onwards and can be used to set the mode in the
> firmware.
>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> [Ulf: Rebased on 4.7 rc1]
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>  drivers/firmware/psci.c   | 22 +++++++++++++++++++++-
>  include/uapi/linux/psci.h |  5 +++++
>  2 files changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
> index 03e0458..3920aba 100644
> --- a/drivers/firmware/psci.c
> +++ b/drivers/firmware/psci.c
> @@ -52,6 +52,7 @@
>   * require cooperation with a Trusted OS driver.
>   */
>  static int resident_cpu = -1;
> +static bool psci_has_osi_pd;
>
>  bool psci_tos_resident_on(int cpu)
>  {
> @@ -563,10 +564,29 @@ out_put_node:
>         return err;
>  }
>
> +static int __init psci_1_0_init(struct device_node *np)
> +{
> +       int ret;
> +
> +       ret = psci_0_2_init(np);
> +       if (ret)
> +               return ret;
> +
> +       /* Check if PSCI OSI mode is available */
> +       ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
> +       if (ret & PSCI_1_0_OS_INITIATED) {
> +               ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
> +               if (!ret)
> +                       psci_has_osi_pd = true;

IMHO, its better to have this done in psci_init_cpu_suspend() itself
for 2 reasons

a] psci_init_cpu_suspend() already calls
psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND])
b] by moving this in psci_init_cpu_suspend() we make this support
available even for ACPI platforms, since psci_acpi_init() calls
psci_probe() and this calls  psci_init_cpu_suspend() for
PSCI_VERSION_MAJOR(ver) >= 1

I even posted a patch [1] yesterday, without being aware of your
patchset for the same.

[1] http://www.spinics.net/lists/arm-kernel/msg513682.html


> +       }
> +
> +       return 0;
> +}
> +
>  static const struct of_device_id psci_of_match[] __initconst = {
>         { .compatible = "arm,psci",     .data = psci_0_1_init},
>         { .compatible = "arm,psci-0.2", .data = psci_0_2_init},
> -       { .compatible = "arm,psci-1.0", .data = psci_0_2_init},
> +       { .compatible = "arm,psci-1.0", .data = psci_1_0_init},
>         {},
>  };
>
> diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
> index 3d7a0fc..7dd778e 100644
> --- a/include/uapi/linux/psci.h
> +++ b/include/uapi/linux/psci.h
> @@ -48,6 +48,7 @@
>
>  #define PSCI_1_0_FN_PSCI_FEATURES              PSCI_0_2_FN(10)
>  #define PSCI_1_0_FN_SYSTEM_SUSPEND             PSCI_0_2_FN(14)
> +#define PSCI_1_0_FN_SET_SUSPEND_MODE           PSCI_0_2_FN(15)
>
>  #define PSCI_1_0_FN64_SYSTEM_SUSPEND           PSCI_0_2_FN64(14)
>
> @@ -93,6 +94,10 @@
>  #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK  \
>                         (0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)
>
> +#define PSCI_1_0_OS_INITIATED                  BIT(0)
> +#define PSCI_1_0_SUSPEND_MODE_PC               0
> +#define PSCI_1_0_SUSPEND_MODE_OSI              1
> +
>  /* PSCI return values (inclusive of all PSCI versions) */
>  #define PSCI_RET_SUCCESS                       0
>  #define PSCI_RET_NOT_SUPPORTED                 -1
> --
> 2.7.4
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Lina Iyer]

On Fri, Jun 24 2016 at 22:25 -0600, Vikas Sajjan wrote:
>Hi Lina,
>
>On Thu, Jun 23, 2016 at 1:06 AM, Lina Iyer <lina.iyer@linaro.org> wrote:
>> PSCI firmware v1.0 onwards may support 2 different modes for
>> CPU_SUSPEND. Platform coordinated mode is the default and every firmware
>> should support it. OS Initiated mode is optional for the firmware to
>> implement and allow Linux to make an better decision on the state of
>> the CPU cluster heirarchy.
>>
>> With the kernel capable of deciding the state for CPU cluster and
>> coherency domains, the OS Initiated mode may now be used by the kernel,
>> provided the firmware supports it. SET_SUSPEND_MODE is a PSCI function
>> available on v1.0 onwards and can be used to set the mode in the
>> firmware.
>>
>> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>> [Ulf: Rebased on 4.7 rc1]
>> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>> ---
>>  drivers/firmware/psci.c   | 22 +++++++++++++++++++++-
>>  include/uapi/linux/psci.h |  5 +++++
>>  2 files changed, 26 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
>> index 03e0458..3920aba 100644
>> --- a/drivers/firmware/psci.c
>> +++ b/drivers/firmware/psci.c
>> @@ -52,6 +52,7 @@
>>   * require cooperation with a Trusted OS driver.
>>   */
>>  static int resident_cpu = -1;
>> +static bool psci_has_osi_pd;
>>
>>  bool psci_tos_resident_on(int cpu)
>>  {
>> @@ -563,10 +564,29 @@ out_put_node:
>>         return err;
>>  }
>>
>> +static int __init psci_1_0_init(struct device_node *np)
>> +{
>> +       int ret;
>> +
>> +       ret = psci_0_2_init(np);
>> +       if (ret)
>> +               return ret;
>> +
>> +       /* Check if PSCI OSI mode is available */
>> +       ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
>> +       if (ret & PSCI_1_0_OS_INITIATED) {
>> +               ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
>> +               if (!ret)
>> +                       psci_has_osi_pd = true;
>
>IMHO, its better to have this done in psci_init_cpu_suspend() itself
>for 2 reasons
>
>a] psci_init_cpu_suspend() already calls
>psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND])
>b] by moving this in psci_init_cpu_suspend() we make this support
>available even for ACPI platforms, since psci_acpi_init() calls
>psci_probe() and this calls  psci_init_cpu_suspend() for
>PSCI_VERSION_MAJOR(ver) >= 1
>
Hmmm.. I can do that.

Thanks,
Lina



>I even posted a patch [1] yesterday, without being aware of your
>patchset for the same.
>
>[1] http://www.spinics.net/lists/arm-kernel/msg513682.html
>
>
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>>  static const struct of_device_id psci_of_match[] __initconst = {
>>         { .compatible = "arm,psci",     .data = psci_0_1_init},
>>         { .compatible = "arm,psci-0.2", .data = psci_0_2_init},
>> -       { .compatible = "arm,psci-1.0", .data = psci_0_2_init},
>> +       { .compatible = "arm,psci-1.0", .data = psci_1_0_init},
>>         {},
>>  };
>>
>> diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
>> index 3d7a0fc..7dd778e 100644
>> --- a/include/uapi/linux/psci.h
>> +++ b/include/uapi/linux/psci.h
>> @@ -48,6 +48,7 @@
>>
>>  #define PSCI_1_0_FN_PSCI_FEATURES              PSCI_0_2_FN(10)
>>  #define PSCI_1_0_FN_SYSTEM_SUSPEND             PSCI_0_2_FN(14)
>> +#define PSCI_1_0_FN_SET_SUSPEND_MODE           PSCI_0_2_FN(15)
>>
>>  #define PSCI_1_0_FN64_SYSTEM_SUSPEND           PSCI_0_2_FN64(14)
>>
>> @@ -93,6 +94,10 @@
>>  #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK  \
>>                         (0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)
>>
>> +#define PSCI_1_0_OS_INITIATED                  BIT(0)
>> +#define PSCI_1_0_SUSPEND_MODE_PC               0
>> +#define PSCI_1_0_SUSPEND_MODE_OSI              1
>> +
>>  /* PSCI return values (inclusive of all PSCI versions) */
>>  #define PSCI_RET_SUCCESS                       0
>>  #define PSCI_RET_NOT_SUPPORTED                 -1
>> --
>> 2.7.4
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Lina Iyer]

On Fri, Jun 24 2016 at 22:25 -0600, Vikas Sajjan wrote:
>Hi Lina,
>
>On Thu, Jun 23, 2016 at 1:06 AM, Lina Iyer <lina.iyer@linaro.org> wrote:
>> PSCI firmware v1.0 onwards may support 2 different modes for
>> CPU_SUSPEND. Platform coordinated mode is the default and every firmware
>> should support it. OS Initiated mode is optional for the firmware to
>> implement and allow Linux to make an better decision on the state of
>> the CPU cluster heirarchy.
>>
>> With the kernel capable of deciding the state for CPU cluster and
>> coherency domains, the OS Initiated mode may now be used by the kernel,
>> provided the firmware supports it. SET_SUSPEND_MODE is a PSCI function
>> available on v1.0 onwards and can be used to set the mode in the
>> firmware.
>>
>> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>> [Ulf: Rebased on 4.7 rc1]
>> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>> ---
>>  drivers/firmware/psci.c   | 22 +++++++++++++++++++++-
>>  include/uapi/linux/psci.h |  5 +++++
>>  2 files changed, 26 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
>> index 03e0458..3920aba 100644
>> --- a/drivers/firmware/psci.c
>> +++ b/drivers/firmware/psci.c
>> @@ -52,6 +52,7 @@
>>   * require cooperation with a Trusted OS driver.
>>   */
>>  static int resident_cpu = -1;
>> +static bool psci_has_osi_pd;
>>
>>  bool psci_tos_resident_on(int cpu)
>>  {
>> @@ -563,10 +564,29 @@ out_put_node:
>>         return err;
>>  }
>>
>> +static int __init psci_1_0_init(struct device_node *np)
>> +{
>> +       int ret;
>> +
>> +       ret = psci_0_2_init(np);
>> +       if (ret)
>> +               return ret;
>> +
>> +       /* Check if PSCI OSI mode is available */
>> +       ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
>> +       if (ret & PSCI_1_0_OS_INITIATED) {
>> +               ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
>> +               if (!ret)
>> +                       psci_has_osi_pd = true;
>
>IMHO, its better to have this done in psci_init_cpu_suspend() itself
>for 2 reasons
>
>a] psci_init_cpu_suspend() already calls
>psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND])
>b] by moving this in psci_init_cpu_suspend() we make this support
>available even for ACPI platforms, since psci_acpi_init() calls
>psci_probe() and this calls  psci_init_cpu_suspend() for
>PSCI_VERSION_MAJOR(ver) >= 1
>
Hmmm.. I can do that.

Thanks,
Lina



>I even posted a patch [1] yesterday, without being aware of your
>patchset for the same.
>
>[1] http://www.spinics.net/lists/arm-kernel/msg513682.html
>
>
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>>  static const struct of_device_id psci_of_match[] __initconst = {
>>         { .compatible = "arm,psci",     .data = psci_0_1_init},
>>         { .compatible = "arm,psci-0.2", .data = psci_0_2_init},
>> -       { .compatible = "arm,psci-1.0", .data = psci_0_2_init},
>> +       { .compatible = "arm,psci-1.0", .data = psci_1_0_init},
>>         {},
>>  };
>>
>> diff --git a/include/uapi/linux/psci.h b/include/uapi/linux/psci.h
>> index 3d7a0fc..7dd778e 100644
>> --- a/include/uapi/linux/psci.h
>> +++ b/include/uapi/linux/psci.h
>> @@ -48,6 +48,7 @@
>>
>>  #define PSCI_1_0_FN_PSCI_FEATURES              PSCI_0_2_FN(10)
>>  #define PSCI_1_0_FN_SYSTEM_SUSPEND             PSCI_0_2_FN(14)
>> +#define PSCI_1_0_FN_SET_SUSPEND_MODE           PSCI_0_2_FN(15)
>>
>>  #define PSCI_1_0_FN64_SYSTEM_SUSPEND           PSCI_0_2_FN64(14)
>>
>> @@ -93,6 +94,10 @@
>>  #define PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK  \
>>                         (0x1 << PSCI_1_0_FEATURES_CPU_SUSPEND_PF_SHIFT)
>>
>> +#define PSCI_1_0_OS_INITIATED                  BIT(0)
>> +#define PSCI_1_0_SUSPEND_MODE_PC               0
>> +#define PSCI_1_0_SUSPEND_MODE_OSI              1
>> +
>>  /* PSCI return values (inclusive of all PSCI versions) */
>>  #define PSCI_RET_SUCCESS                       0
>>  #define PSCI_RET_NOT_SUPPORTED                 -1
>> --
>> 2.7.4
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Mark Rutland]

On Fri, Jun 24, 2016 at 09:55:20AM +0530, Vikas Sajjan wrote:
> On Thu, Jun 23, 2016 at 1:06 AM, Lina Iyer <lina.iyer@linaro.org> wrote:
> > +static int __init psci_1_0_init(struct device_node *np)
> > +{
> > +       int ret;
> > +
> > +       ret = psci_0_2_init(np);
> > +       if (ret)
> > +               return ret;
> > +
> > +       /* Check if PSCI OSI mode is available */
> > +       ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
> > +       if (ret & PSCI_1_0_OS_INITIATED) {
> > +               ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
> > +               if (!ret)
> > +                       psci_has_osi_pd = true;
> 
> IMHO, its better to have this done in psci_init_cpu_suspend() itself
> for 2 reasons
> 
> a] psci_init_cpu_suspend() already calls
> psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND])
> b] by moving this in psci_init_cpu_suspend() we make this support
> available even for ACPI platforms, since psci_acpi_init() calls
> psci_probe() and this calls  psci_init_cpu_suspend() for
> PSCI_VERSION_MAJOR(ver) >= 1

For ACPI platforms it is necessary to go through a handshake to
determine whether LPI can use OSI (see 6.2.11.2 in the ACPI 6.1 spec).
So there will have to be some ACPI-specific code to determine whether
OSI should be used.

We will probably have to an ACPI-specific wrapper for
psci_init_cpu_suspend to cater for that. I don't think that
psci_init_cpu_suspend itself should be in charge of deciding whether to
enable OSI.

Thanks,
Mark.

[PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Mark Rutland]

On Fri, Jun 24, 2016 at 09:55:20AM +0530, Vikas Sajjan wrote:
> On Thu, Jun 23, 2016 at 1:06 AM, Lina Iyer <lina.iyer@linaro.org> wrote:
> > +static int __init psci_1_0_init(struct device_node *np)
> > +{
> > +       int ret;
> > +
> > +       ret = psci_0_2_init(np);
> > +       if (ret)
> > +               return ret;
> > +
> > +       /* Check if PSCI OSI mode is available */
> > +       ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
> > +       if (ret & PSCI_1_0_OS_INITIATED) {
> > +               ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
> > +               if (!ret)
> > +                       psci_has_osi_pd = true;
> 
> IMHO, its better to have this done in psci_init_cpu_suspend() itself
> for 2 reasons
> 
> a] psci_init_cpu_suspend() already calls
> psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND])
> b] by moving this in psci_init_cpu_suspend() we make this support
> available even for ACPI platforms, since psci_acpi_init() calls
> psci_probe() and this calls  psci_init_cpu_suspend() for
> PSCI_VERSION_MAJOR(ver) >= 1

For ACPI platforms it is necessary to go through a handshake to
determine whether LPI can use OSI (see 6.2.11.2 in the ACPI 6.1 spec).
So there will have to be some ACPI-specific code to determine whether
OSI should be used.

We will probably have to an ACPI-specific wrapper for
psci_init_cpu_suspend to cater for that. I don't think that
psci_init_cpu_suspend itself should be in charge of deciding whether to
enable OSI.

Thanks,
Mark.

Re: [PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Vikas Sajjan]

Hi Mark,

On Mon, Jun 27, 2016 at 3:42 PM, Mark Rutland <mark.rutland@arm.com> wrote:
> On Fri, Jun 24, 2016 at 09:55:20AM +0530, Vikas Sajjan wrote:
>> On Thu, Jun 23, 2016 at 1:06 AM, Lina Iyer <lina.iyer@linaro.org> wrote:
>> > +static int __init psci_1_0_init(struct device_node *np)
>> > +{
>> > +       int ret;
>> > +
>> > +       ret = psci_0_2_init(np);
>> > +       if (ret)
>> > +               return ret;
>> > +
>> > +       /* Check if PSCI OSI mode is available */
>> > +       ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
>> > +       if (ret & PSCI_1_0_OS_INITIATED) {
>> > +               ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
>> > +               if (!ret)
>> > +                       psci_has_osi_pd = true;
>>
>> IMHO, its better to have this done in psci_init_cpu_suspend() itself
>> for 2 reasons
>>
>> a] psci_init_cpu_suspend() already calls
>> psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND])
>> b] by moving this in psci_init_cpu_suspend() we make this support
>> available even for ACPI platforms, since psci_acpi_init() calls
>> psci_probe() and this calls  psci_init_cpu_suspend() for
>> PSCI_VERSION_MAJOR(ver) >= 1
>
> For ACPI platforms it is necessary to go through a handshake to
> determine whether LPI can use OSI (see 6.2.11.2 in the ACPI 6.1 spec).
> So there will have to be some ACPI-specific code to determine whether
> OSI should be used.
>
> We will probably have to an ACPI-specific wrapper for
> psci_init_cpu_suspend to cater for that. I don't think that
> psci_init_cpu_suspend itself should be in charge of deciding whether to
> enable OSI.

True, I think you are referring to the function acpi_bus_osc_support()
which does the handing shaking.
Right, for ACPI platforms along with SET_SUSPEND_MODE feature, we
should also be depending on the handing shaking result to set the
psci_has_osi_pd flag.


>
> Thanks,
> Mark.

Thanks and Regards
Vikas Sajjan
Hewlett Packard Enterprise

[PATCH 11/14] drivers: firmware: psci: Allow OS Initiated suspend mode

[Vikas Sajjan]

Hi Mark,

On Mon, Jun 27, 2016 at 3:42 PM, Mark Rutland <mark.rutland@arm.com> wrote:
> On Fri, Jun 24, 2016 at 09:55:20AM +0530, Vikas Sajjan wrote:
>> On Thu, Jun 23, 2016 at 1:06 AM, Lina Iyer <lina.iyer@linaro.org> wrote:
>> > +static int __init psci_1_0_init(struct device_node *np)
>> > +{
>> > +       int ret;
>> > +
>> > +       ret = psci_0_2_init(np);
>> > +       if (ret)
>> > +               return ret;
>> > +
>> > +       /* Check if PSCI OSI mode is available */
>> > +       ret = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
>> > +       if (ret & PSCI_1_0_OS_INITIATED) {
>> > +               ret = psci_features(PSCI_1_0_FN_SET_SUSPEND_MODE);
>> > +               if (!ret)
>> > +                       psci_has_osi_pd = true;
>>
>> IMHO, its better to have this done in psci_init_cpu_suspend() itself
>> for 2 reasons
>>
>> a] psci_init_cpu_suspend() already calls
>> psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND])
>> b] by moving this in psci_init_cpu_suspend() we make this support
>> available even for ACPI platforms, since psci_acpi_init() calls
>> psci_probe() and this calls  psci_init_cpu_suspend() for
>> PSCI_VERSION_MAJOR(ver) >= 1
>
> For ACPI platforms it is necessary to go through a handshake to
> determine whether LPI can use OSI (see 6.2.11.2 in the ACPI 6.1 spec).
> So there will have to be some ACPI-specific code to determine whether
> OSI should be used.
>
> We will probably have to an ACPI-specific wrapper for
> psci_init_cpu_suspend to cater for that. I don't think that
> psci_init_cpu_suspend itself should be in charge of deciding whether to
> enable OSI.

True, I think you are referring to the function acpi_bus_osc_support()
which does the handing shaking.
Right, for ACPI platforms along with SET_SUSPEND_MODE feature, we
should also be depending on the handing shaking result to set the
psci_has_osi_pd flag.


>
> Thanks,
> Mark.

Thanks and Regards
Vikas Sajjan
Hewlett Packard Enterprise

Re: [PATCH 05/14] PM / doc: update device documentation for devices in IRQ safe PM domains

[Kevin Hilman]

Lina Iyer <lina.iyer@linaro.org> writes:

> Update documentation to reflect the changes made to support IRQ safe PM
> domains.
>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> ---
>  Documentation/power/devices.txt | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
> index 8ba6625..a622136 100644
> --- a/Documentation/power/devices.txt
> +++ b/Documentation/power/devices.txt
> @@ -607,7 +607,17 @@ individually.  Instead, a set of devices sharing a power resource can be put
>  into a low-power state together at the same time by turning off the shared
>  power resource.  Of course, they also need to be put into the full-power state
>  together, by turning the shared power resource on.  A set of devices with this
> -property is often referred to as a power domain.
> +property is often referred to as a power domain. A power domain may also be
> +nested inside another power domain.
> +
> +Devices, by default, operate in process context. If a device can operate in

minor nit: By "devices" here, I think you mean the runtime PM callbacks for
devices?  If so, it should be explicit, otherwise it's not clear what it
means for devices to operate in process context.

Kevin

[PATCH 05/14] PM / doc: update device documentation for devices in IRQ safe PM domains

[Kevin Hilman]

Lina Iyer <lina.iyer@linaro.org> writes:

> Update documentation to reflect the changes made to support IRQ safe PM
> domains.
>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
> ---
>  Documentation/power/devices.txt | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
> index 8ba6625..a622136 100644
> --- a/Documentation/power/devices.txt
> +++ b/Documentation/power/devices.txt
> @@ -607,7 +607,17 @@ individually.  Instead, a set of devices sharing a power resource can be put
>  into a low-power state together at the same time by turning off the shared
>  power resource.  Of course, they also need to be put into the full-power state
>  together, by turning the shared power resource on.  A set of devices with this
> -property is often referred to as a power domain.
> +property is often referred to as a power domain. A power domain may also be
> +nested inside another power domain.
> +
> +Devices, by default, operate in process context. If a device can operate in

minor nit: By "devices" here, I think you mean the runtime PM callbacks for
devices?  If so, it should be explicit, otherwise it's not clear what it
means for devices to operate in process context.

Kevin

Re: [PATCH 05/14] PM / doc: update device documentation for devices in IRQ safe PM domains

[Lina Iyer]

On Mon, Jul 25 2016 at 16:50 -0600, Kevin Hilman wrote:
>Lina Iyer <lina.iyer@linaro.org> writes:
>
>> Update documentation to reflect the changes made to support IRQ safe PM
>> domains.
>>
>> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>> ---
>>  Documentation/power/devices.txt | 12 +++++++++++-
>>  1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
>> index 8ba6625..a622136 100644
>> --- a/Documentation/power/devices.txt
>> +++ b/Documentation/power/devices.txt
>> @@ -607,7 +607,17 @@ individually.  Instead, a set of devices sharing a power resource can be put
>>  into a low-power state together at the same time by turning off the shared
>>  power resource.  Of course, they also need to be put into the full-power state
>>  together, by turning the shared power resource on.  A set of devices with this
>> -property is often referred to as a power domain.
>> +property is often referred to as a power domain. A power domain may also be
>> +nested inside another power domain.
>> +
>> +Devices, by default, operate in process context. If a device can operate in
>
>minor nit: By "devices" here, I think you mean the runtime PM callbacks for
>devices?  If so, it should be explicit, otherwise it's not clear what it
>means for devices to operate in process context.
>
You are right. Its runtime PM that is of interest here.

Thanks,
Lina

[PATCH 05/14] PM / doc: update device documentation for devices in IRQ safe PM domains

[Lina Iyer]

On Mon, Jul 25 2016 at 16:50 -0600, Kevin Hilman wrote:
>Lina Iyer <lina.iyer@linaro.org> writes:
>
>> Update documentation to reflect the changes made to support IRQ safe PM
>> domains.
>>
>> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>> ---
>>  Documentation/power/devices.txt | 12 +++++++++++-
>>  1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
>> index 8ba6625..a622136 100644
>> --- a/Documentation/power/devices.txt
>> +++ b/Documentation/power/devices.txt
>> @@ -607,7 +607,17 @@ individually.  Instead, a set of devices sharing a power resource can be put
>>  into a low-power state together at the same time by turning off the shared
>>  power resource.  Of course, they also need to be put into the full-power state
>>  together, by turning the shared power resource on.  A set of devices with this
>> -property is often referred to as a power domain.
>> +property is often referred to as a power domain. A power domain may also be
>> +nested inside another power domain.
>> +
>> +Devices, by default, operate in process context. If a device can operate in
>
>minor nit: By "devices" here, I think you mean the runtime PM callbacks for
>devices?  If so, it should be explicit, otherwise it's not clear what it
>means for devices to operate in process context.
>
You are right. Its runtime PM that is of interest here.

Thanks,
Lina

Re: [PATCH 08/14] timer: Export next wake up of a CPU

[Kevin Hilman]

Lina Iyer <lina.iyer@linaro.org> writes:

> Knowing the sleep length of the CPU is useful for the power state
> determination on idle. However, when the common sleep time between
> multiple CPUs is needed, the sleep length of a CPU is not useful.

You need more about "why" it's not useful.  e.g. CPU sleep length is
relative to when that CPU entered idle, whereas when trying to determine
cluster sleep time, absolute times are needed, like dev->next_event.

> By reading the next wake up event of a CPU, governors can determine the
> first CPU to wake up (due to timer) amongst a cluster of CPUs and the
> sleep time available between the last CPU to idle and the first CPU to
> resume. This information is useful to determine if the caches and other
> common hardware blocks can also be put in idle during this common period
> of inactivity.
>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>

Otherwise, looks OK to me.

Reviewed-by: Kevin Hilman <khilman@baylibre.com>

> ---
>  include/linux/tick.h     | 10 ++++++++++
>  kernel/time/tick-sched.c | 13 +++++++++++++
>  2 files changed, 23 insertions(+)
>
> diff --git a/include/linux/tick.h b/include/linux/tick.h
> index 62be0786..9535141 100644
> --- a/include/linux/tick.h
> +++ b/include/linux/tick.h
> @@ -117,6 +117,7 @@ extern void tick_nohz_idle_enter(void);
>  extern void tick_nohz_idle_exit(void);
>  extern void tick_nohz_irq_exit(void);
>  extern ktime_t tick_nohz_get_sleep_length(void);
> +extern ktime_t tick_nohz_get_next_wakeup(int cpu);
>  extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
>  extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
>  #else /* !CONFIG_NO_HZ_COMMON */
> @@ -131,6 +132,15 @@ static inline ktime_t tick_nohz_get_sleep_length(void)
>  
>  	return len;
>  }
> +
> +static inline ktime_t tick_nohz_get_next_wakeup(int cpu)
> +{
> +	ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
> +
> +	/* Next wake up is the tick period, assume it starts now */
> +	return ktime_add(len, ktime_get());
> +}
> +
>  static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
>  static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
>  #endif /* !CONFIG_NO_HZ_COMMON */
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 536ada8..addf3235 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -979,6 +979,19 @@ ktime_t tick_nohz_get_sleep_length(void)
>  	return ts->sleep_length;
>  }
>  
> +/**
> + * tick_nohz_get_next_wakeup - return the next wake up of the CPU
> + *
> + * Called with interrupts disabled on the cpu
> + */
> +ktime_t tick_nohz_get_next_wakeup(int cpu)
> +{
> +	struct clock_event_device *dev =
> +			per_cpu(tick_cpu_device.evtdev, cpu);
> +
> +	return dev->next_event;
> +}
> +
>  static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
>  {
>  #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE

[PATCH 08/14] timer: Export next wake up of a CPU

[Kevin Hilman]

Lina Iyer <lina.iyer@linaro.org> writes:

> Knowing the sleep length of the CPU is useful for the power state
> determination on idle. However, when the common sleep time between
> multiple CPUs is needed, the sleep length of a CPU is not useful.

You need more about "why" it's not useful.  e.g. CPU sleep length is
relative to when that CPU entered idle, whereas when trying to determine
cluster sleep time, absolute times are needed, like dev->next_event.

> By reading the next wake up event of a CPU, governors can determine the
> first CPU to wake up (due to timer) amongst a cluster of CPUs and the
> sleep time available between the last CPU to idle and the first CPU to
> resume. This information is useful to determine if the caches and other
> common hardware blocks can also be put in idle during this common period
> of inactivity.
>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Lina Iyer <lina.iyer@linaro.org>

Otherwise, looks OK to me.

Reviewed-by: Kevin Hilman <khilman@baylibre.com>

> ---
>  include/linux/tick.h     | 10 ++++++++++
>  kernel/time/tick-sched.c | 13 +++++++++++++
>  2 files changed, 23 insertions(+)
>
> diff --git a/include/linux/tick.h b/include/linux/tick.h
> index 62be0786..9535141 100644
> --- a/include/linux/tick.h
> +++ b/include/linux/tick.h
> @@ -117,6 +117,7 @@ extern void tick_nohz_idle_enter(void);
>  extern void tick_nohz_idle_exit(void);
>  extern void tick_nohz_irq_exit(void);
>  extern ktime_t tick_nohz_get_sleep_length(void);
> +extern ktime_t tick_nohz_get_next_wakeup(int cpu);
>  extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time);
>  extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time);
>  #else /* !CONFIG_NO_HZ_COMMON */
> @@ -131,6 +132,15 @@ static inline ktime_t tick_nohz_get_sleep_length(void)
>  
>  	return len;
>  }
> +
> +static inline ktime_t tick_nohz_get_next_wakeup(int cpu)
> +{
> +	ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
> +
> +	/* Next wake up is the tick period, assume it starts now */
> +	return ktime_add(len, ktime_get());
> +}
> +
>  static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
>  static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
>  #endif /* !CONFIG_NO_HZ_COMMON */
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 536ada8..addf3235 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -979,6 +979,19 @@ ktime_t tick_nohz_get_sleep_length(void)
>  	return ts->sleep_length;
>  }
>  
> +/**
> + * tick_nohz_get_next_wakeup - return the next wake up of the CPU
> + *
> + * Called with interrupts disabled on the cpu
> + */
> +ktime_t tick_nohz_get_next_wakeup(int cpu)
> +{
> +	struct clock_event_device *dev =
> +			per_cpu(tick_cpu_device.evtdev, cpu);
> +
> +	return dev->next_event;
> +}
> +
>  static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
>  {
>  #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE

Re: [PATCH 00/14] PM: SoC idle support using PM domains

[Kevin Hilman]

Lina Iyer <lina.iyer@linaro.org> writes:

> Hi all,
>
> Changes since RFC-v3:
> - Reorganize the patches. Documentations have their own patch.
> - Moved code around with PSCI OS initiated so they would not have compiler
>   errors in other configuration.
> - Minor bug fixes with genpd power_on functionality.
> - Rebased on top of 4.7-rc1

This is looking good.  I've had a quick look through this, as well as
tested it on apq8016-sbc (dragon 410c.)

Seems the main thing left to resolve is the DT description.

Kevin

[PATCH 00/14] PM: SoC idle support using PM domains

[Kevin Hilman]

Lina Iyer <lina.iyer@linaro.org> writes:

> Hi all,
>
> Changes since RFC-v3:
> - Reorganize the patches. Documentations have their own patch.
> - Moved code around with PSCI OS initiated so they would not have compiler
>   errors in other configuration.
> - Minor bug fixes with genpd power_on functionality.
> - Rebased on top of 4.7-rc1

This is looking good.  I've had a quick look through this, as well as
tested it on apq8016-sbc (dragon 410c.)

Seems the main thing left to resolve is the DT description.

Kevin

Re: [PATCH 08/14] timer: Export next wake up of a CPU

[Thomas Gleixner]

On Wed, 22 Jun 2016, Lina Iyer wrote:
> +static inline ktime_t tick_nohz_get_next_wakeup(int cpu)
> +{
> +	ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
> +
> +	/* Next wake up is the tick period, assume it starts now */
> +	return ktime_add(len, ktime_get());

  return tick_next_period;

Will tell you the point where the next tick interrupt is due.

> +}
> +
>  static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
>  static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
>  #endif /* !CONFIG_NO_HZ_COMMON */
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 536ada8..addf3235 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -979,6 +979,19 @@ ktime_t tick_nohz_get_sleep_length(void)
>  	return ts->sleep_length;
>  }
>  
> +/**
> + * tick_nohz_get_next_wakeup - return the next wake up of the CPU
> + *
> + * Called with interrupts disabled on the cpu

So why are you handing in the (undocumented) cpu argument if its called on
that cpu anyway?

> + */
> +ktime_t tick_nohz_get_next_wakeup(int cpu)
> +{
> +	struct clock_event_device *dev =
> +			per_cpu(tick_cpu_device.evtdev, cpu);
> +
> +	return dev->next_event;

Then this becomes

     return __this_cpu_read(tick_cpu_device.evtdev)->nextevt;

Thanks,

	tglx

[PATCH 08/14] timer: Export next wake up of a CPU

[Thomas Gleixner]

On Wed, 22 Jun 2016, Lina Iyer wrote:
> +static inline ktime_t tick_nohz_get_next_wakeup(int cpu)
> +{
> +	ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
> +
> +	/* Next wake up is the tick period, assume it starts now */
> +	return ktime_add(len, ktime_get());

  return tick_next_period;

Will tell you the point where the next tick interrupt is due.

> +}
> +
>  static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
>  static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
>  #endif /* !CONFIG_NO_HZ_COMMON */
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 536ada8..addf3235 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -979,6 +979,19 @@ ktime_t tick_nohz_get_sleep_length(void)
>  	return ts->sleep_length;
>  }
>  
> +/**
> + * tick_nohz_get_next_wakeup - return the next wake up of the CPU
> + *
> + * Called with interrupts disabled on the cpu

So why are you handing in the (undocumented) cpu argument if its called on
that cpu anyway?

> + */
> +ktime_t tick_nohz_get_next_wakeup(int cpu)
> +{
> +	struct clock_event_device *dev =
> +			per_cpu(tick_cpu_device.evtdev, cpu);
> +
> +	return dev->next_event;

Then this becomes

     return __this_cpu_read(tick_cpu_device.evtdev)->nextevt;

Thanks,

	tglx

[draft] Re: [PATCH 02/14] dt/bindings: update binding for PM domain idle states

[Brendan Jackman]

[-- Attachment #1: Type: text/plain, Size: 8429 bytes --]

Hi folks,

I'm trying to start a conversation with Lina about using the
power-domains DT bindings for describing the EAS power model.

Partly because I'm still waiting for fossmail approval so I can't send
this email to anyone without an @arm.com address, I wanted to circulate
a draft internally before I make a fool of myself pubicly; does this
mail make sense to you guys (also please let me know if I'm egregiously
breaking linux-pm etiquette)?

Cheers,
Brendan

======================================================================

Hi Lina, Mark,

I'm currently investigating a generic way of expressing in DT the power
costs of CPU idle states, for use by the energy model for Energy Aware
Scheduling (EAS) [1][2].

Essentially what I want to do is probably add a "power-usage" property
to idle state nodes. I have heard that you and/or Kevin Hilman have
actually experimented with something similar.

However, the model is required to be topologically aware: for each idle
state, we want to know the power usage of the CPU, as well as of the
cluster-level resources it shares. This has led me to this patchset,
since the CPU power domain bindings allow you to tell which topology
level "owns" an idle state.

I guess my point here is that these bindings have another use-case
besides OS-coordinated cluster idle. I've hacked up a patch (attached)
for my experimentation which allows the bindings as described in this
mail to be used without any of the actual CPU Runtime PM implementation

I share Mark's concern about the duplication between cpu-idle-states in
CPU nodes and power-states in power domain nodes. As I understand it,
with this patchset the boundary between cpu-idle-states and power-states
nodes translates to the boundary between states managed by cpuidle and
states managed by Runtime PM.

Mark hinted at a solution where idle state nodes refer to the power
domains they affect. I guess this solution would look something like:

CPU_0: cpu@0 {
        compatible = "example-cpu";
        reg = <0x0 0x0>;
        device_type = "cpu";
        enable-method = "psci";
        cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
        power-domains = <&CLUSTER_PD>;
};

/* ... elsewhere ... */

idle-states {
        CPU_SLEEP: cpu-sleep {
                compatible = "arm,idle-state";
                arm,psci-suspend-param = <0x0010000>;
                entry-latency-us = <100>;
                exit-latency-us = <250>;
                min-residency-us = <150>;
        };

        CLUSTER_SLEEP: cluster-sleep {
                compatible = "arm,idle-state";
                arm,psci-suspend-param = <0x1010000>;
                entry-latency-us = <800>;
                exit-latency-us = <700>;
                min-residency-us = <2500>;
                affects-power-domains = <&CLUSTER_PD>
        };
};

Then if desired/necessary, CLUSTER_SLEEP can be taken care of by Runtime
PM (i.e. become a genpd_power_state) rather than cpuidle, the deciding
factor being that it has an affects-power-domain property. (In this
model, idle state nodes don't have a power-states property at all.)

Mark, have I understood you correctly, is that what you were imagining?


On 23/06/16 19:39, Lina Iyer wrote:
> On Thu, Jun 23 2016 at 12:19 -0600, Mark Rutland wrote:
>> On Thu, Jun 23, 2016 at 12:04:51PM -0600, Lina Iyer wrote:
>>> Hi Mark,
>>>
>>> On Thu, Jun 23 2016 at 11:35 -0600, Mark Rutland wrote:
>>> >Hi,
>>> >
>>> >On Wed, Jun 22, 2016 at 01:36:37PM -0600, Lina Iyer wrote:
>>> >>From: Axel Haslam <ahaslam+renesas@baylibre.com>
>>> >>
>>> >>Update DT bindings to describe idle states of PM domains.
>>> >>
>>> >>Cc: <devicetree@vger.kernel.org>
>>> >>Signed-off-by: Marc Titinger <mtitinger+renesas@baylibre.com>
>>> >>Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
>>> >>[Lina: Added state properties, removed state names, wakeup-latency,
>>> >>added of_pm_genpd_init() API, pruned commit text]
>>> >>Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
>>> >>[Ulf: Moved around code to make it compile properly, rebased on top
>>> of multiple state support]
>>> >>---
>>> >> .../devicetree/bindings/power/power_domain.txt     | 70
>>> ++++++++++++++++++++++
>>> >> 1 file changed, 70 insertions(+)
>>> >>
>>> >>diff --git
>>> a/Documentation/devicetree/bindings/power/power_domain.txt
>>> b/Documentation/devicetree/bindings/power/power_domain.txt
>>> >>index 025b5e7..41e8dda 100644
>>> >>--- a/Documentation/devicetree/bindings/power/power_domain.txt
>>> >>+++ b/Documentation/devicetree/bindings/power/power_domain.txt
>>> >>@@ -29,6 +29,43 @@ Optional properties:
>>> >>    specified by this binding. More details about power domain
>>> specifier are
>>> >>    available in the next section.
>>> >>
>>> >>+- power-states : A phandle of an idle-state that shall be soaked
>>> into a
>>> >>+                generic domain power state.
>>> >
>>> >It's somewhat unfortunate that this gives us two possible locations for
>>> >idle state lists (under the /cpus node and in a pm-domains node),
>>> >especially as it's not clear what would happen were a DT to have both.
>>> >
>>> >I would prefer that we extend the existing bindings such that states
>>> can
>>> >refer to the power domains which they affect.
>>> >
>>> I agree. The CPU idle states have become defined to be specific to CPUs.
>>> PM Domain idle states are generic for any type of domain. I am hoping at
>>> some point, we could converge and use the same idle state, but that
>>> would mean changing the CPU idle states to make it generic.
>>
>> Outside of CPU idling, I don't fully understand how this will be used,
>> so it's not clear to me what would need to be made generic. Apologies
>> for my ignorance there.
>>
> There may be non-PSCI ARM v7 CPU domains that may have domain controller
> drivers in the kernel. They would not hook into the ARM PSCI frameworks.
> It is still cpuidle though.
>

Apologies also for my ignorance, but I don't think I understand you
here. It sounds to me like the drivers you're describing are currently
unable to get their idle states from DT - is that correct? If so,
perhaps we can implement support using the CPU idle state nodes at
first, then later make them generic so that these non-PSCI domains can
use DT.

>>> At some point, during my development, I did use the arm,idle-state for
>>> domains as well, but the binding definitions were too restrictive for
>>> a generic PM domain.
>>>
>>> I would be willing to make the change to CPU idle states to make it
>>> generic and then we could just reference domain and CPU idle states
>>> using the same bindings. Are we okay with that, specifically,
>>> arm,psci-suspend-param? This binding is very restrictive in its
>>> description. What we pass to the platform driver upon choosing a domain
>>> state is very platform specific and therefore has to be generic in its
>>> description.
>>
>> I was suggesting that for PSCI we should consistently us
>> arm,psci-suspend-param, not that this should be used for all power
>> domain state data.
>>
>> I imagine that mechanisms for powering down power domains will have
>> varied requirements on data they require (and may require more than can
>> be encoded in a u32), and I don't think it's best to try to force a
>> single representation in the DT for that. It would be better to allow
>> them to define the properties which they require.
>>
> The only way to do that is to push the DT parsing to the platform
> drivers. In the case of CPU domains controlled by PSCI, we could use the
> arm,idle-states but any other generic domain, may need to define their
> own bindings and fill up the domain states before initiailizing the domain.
>
> While this approach pushes the onus on to the platform code, I am fine
> with it. Is that what you were thinking too?

[1]
http://www.linaro.org/blog/core-dump/energy-aware-scheduling-eas-progress-update/

[2] https://lkml.org/lkml/2015/7/7/754
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[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-cpuidle-dt-Parse-states-from-power-domain-nodes.patch --]
[-- Type: text/x-patch; name=0001-cpuidle-dt-Parse-states-from-power-domain-nodes.patch, Size: 4742 bytes --]

>From 598a7acb19af3763aa17926168e24d8131f3a57d Mon Sep 17 00:00:00 2001
From: Brendan Jackman <brendan.jackman@arm.com>
Date: Mon, 25 Jul 2016 14:26:08 +0100
Subject: [PATCH] cpuidle: dt: Parse states from power domain nodes

This commit allows bindings similar to those in [1] to be used without
requiring CPU PM domains. The cpuidle DT parsing code will first read
idle states from the "cpu-idle-states" property, then walk up the
power-domains tree (assuming that it is indeed a tree) for the CPU and
read idle states from the "power-states" property.

This is a temporary hack to enable a prototype EAS energy model in the
device tree, for which we want to use CPU power-domains to describe
energy costs in a topologically-aware way.

[1] https://patchwork.kernel.org/patch/9193651/
---
 drivers/cpuidle/dt_idle_states.c | 85 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 82 insertions(+), 3 deletions(-)

diff --git a/drivers/cpuidle/dt_idle_states.c b/drivers/cpuidle/dt_idle_states.c
index a5c111b..70fe30b 100644
--- a/drivers/cpuidle/dt_idle_states.c
+++ b/drivers/cpuidle/dt_idle_states.c
@@ -21,6 +21,8 @@
 
 #include "dt_idle_states.h"
 
+#define MAX_PD_DEPTH 8
+
 static int init_state_node(struct cpuidle_state *idle_state,
 			   const struct of_device_id *matches,
 			   struct device_node *state_node)
@@ -92,6 +94,84 @@ static int init_state_node(struct cpuidle_state *idle_state,
 }
 
 /*
+ * First look in cpu-idle-states, then walk up the power-domains tree, returning
+ * the idx'th idle state node encountered, or NULL if it can't be found.
+ *
+ * Returns the device_node pointer with refcount incremented.  Use
+ * of_node_put() on it when done.
+ */
+static struct device_node *get_idle_state_node(struct device_node *cpu_node,
+					       int idx)
+{
+	struct device_node *state_node, *consumer_node;
+	int num_cpu_idle_states, num_pd_idle_states;
+	int idx_pd;
+	unsigned int i;
+
+	state_node = of_parse_phandle(cpu_node, "cpu-idle-states", idx);
+	if (state_node)
+		return state_node;
+
+	num_cpu_idle_states = of_property_count_elems_of_size(cpu_node,
+							      "cpu-idle-states",
+							      4);
+	if (num_cpu_idle_states < 1) {
+		pr_devel("%s: no cpu-idle-states for %s\n", __func__,
+			 cpu_node->name);
+		num_cpu_idle_states = 0;
+	}
+
+	pr_devel("%s: Looking in %s's power domains tree for state %d\n",
+		 __func__, cpu_node->full_name, idx);
+
+	BUG_ON(idx < num_cpu_idle_states);
+	idx_pd = idx - num_cpu_idle_states;
+
+	/* Use a loop counter so we don't infiniloop if there's a cycle in the
+	 * power-domains graph. */
+	consumer_node = cpu_node;
+	for (i = 0; i < MAX_PD_DEPTH; i++) {
+		int num_pd_providers;
+		struct device_node *pd_node = of_parse_phandle(
+			consumer_node, "power-domains", 0);
+		if (!pd_node) {
+			return NULL;
+		}
+
+		/* We're assuming the power-domains graph is a tree, complain if
+		 * not. */
+		num_pd_providers = of_property_count_elems_of_size(
+			consumer_node, "power-domains", 4);
+		BUG_ON(num_pd_providers < 1);
+		if (num_pd_providers > 1)
+			pr_warn("power-domains graph for %s not a tree "
+				"(%s has multiple power-domains)\n",
+				cpu_node->full_name, consumer_node->full_name);
+
+
+		state_node = of_parse_phandle(pd_node, "power-states", idx_pd);
+		if (state_node) {
+			of_node_put(pd_node);
+			return state_node;
+		}
+
+		num_pd_idle_states = of_property_count_elems_of_size(
+			pd_node, "power-states", 4);
+		if (num_pd_idle_states < 1)
+			num_pd_idle_states = 0;
+
+		BUG_ON(idx_pd < num_pd_idle_states);
+		idx_pd -= num_pd_idle_states;
+
+		of_node_put(pd_node);
+		consumer_node = pd_node;
+	}
+
+	WARN(1, "DT CPU power domain graph too deep. Probably has a cycle.");
+	return NULL;
+}
+
+/*
  * Check that the idle state is uniform across all CPUs in the CPUidle driver
  * cpumask
  */
@@ -112,8 +192,7 @@ static bool idle_state_valid(struct device_node *state_node, unsigned int idx,
 	for (cpu = cpumask_next(cpumask_first(cpumask), cpumask);
 	     cpu < nr_cpu_ids; cpu = cpumask_next(cpu, cpumask)) {
 		cpu_node = of_cpu_device_node_get(cpu);
-		curr_state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
-						   idx);
+		curr_state_node = get_idle_state_node(cpu_node, idx);
 		if (state_node != curr_state_node)
 			valid = false;
 
@@ -170,7 +249,7 @@ int dt_init_idle_driver(struct cpuidle_driver *drv,
 	cpu_node = of_cpu_device_node_get(cpumask_first(cpumask));
 
 	for (i = 0; ; i++) {
-		state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
+		state_node = get_idle_state_node(cpu_node,i);
 		if (!state_node)
 			break;
 
-- 
1.9.1

Re: [PATCH 08/14] timer: Export next wake up of a CPU

[Lina Iyer]

On Wed, Jul 27 2016 at 03:16 -0600, Thomas Gleixner wrote:
>On Wed, 22 Jun 2016, Lina Iyer wrote:
>> +static inline ktime_t tick_nohz_get_next_wakeup(int cpu)
>> +{
>> +	ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
>> +
>> +	/* Next wake up is the tick period, assume it starts now */
>> +	return ktime_add(len, ktime_get());
>
>  return tick_next_period;
>
>Will tell you the point where the next tick interrupt is due.
>
That definitely is better, will change.

>> +}
>> +
>>  static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
>>  static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
>>  #endif /* !CONFIG_NO_HZ_COMMON */
>> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
>> index 536ada8..addf3235 100644
>> --- a/kernel/time/tick-sched.c
>> +++ b/kernel/time/tick-sched.c
>> @@ -979,6 +979,19 @@ ktime_t tick_nohz_get_sleep_length(void)
>>  	return ts->sleep_length;
>>  }
>>
>> +/**
>> + * tick_nohz_get_next_wakeup - return the next wake up of the CPU
>> + *
>> + * Called with interrupts disabled on the cpu
>
>So why are you handing in the (undocumented) cpu argument if its called on
>that cpu anyway?
>
Oh, my comment is very misleading. The function may be called from any
CPU for any other CPU. It should be more like "Called when the
interrupts are disabled on the CPU". I guess that doesn't make sense
either. I will remove this comment.

Thanks,
Lina

>> + */
>> +ktime_t tick_nohz_get_next_wakeup(int cpu)
>> +{
>> +	struct clock_event_device *dev =
>> +			per_cpu(tick_cpu_device.evtdev, cpu);
>> +
>> +	return dev->next_event;
>
>Then this becomes
>
>     return __this_cpu_read(tick_cpu_device.evtdev)->nextevt;
>
>Thanks,
>
>	tglx

[PATCH 08/14] timer: Export next wake up of a CPU

[Lina Iyer]

On Wed, Jul 27 2016 at 03:16 -0600, Thomas Gleixner wrote:
>On Wed, 22 Jun 2016, Lina Iyer wrote:
>> +static inline ktime_t tick_nohz_get_next_wakeup(int cpu)
>> +{
>> +	ktime_t len = { .tv64 = NSEC_PER_SEC/HZ };
>> +
>> +	/* Next wake up is the tick period, assume it starts now */
>> +	return ktime_add(len, ktime_get());
>
>  return tick_next_period;
>
>Will tell you the point where the next tick interrupt is due.
>
That definitely is better, will change.

>> +}
>> +
>>  static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; }
>>  static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; }
>>  #endif /* !CONFIG_NO_HZ_COMMON */
>> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
>> index 536ada8..addf3235 100644
>> --- a/kernel/time/tick-sched.c
>> +++ b/kernel/time/tick-sched.c
>> @@ -979,6 +979,19 @@ ktime_t tick_nohz_get_sleep_length(void)
>>  	return ts->sleep_length;
>>  }
>>
>> +/**
>> + * tick_nohz_get_next_wakeup - return the next wake up of the CPU
>> + *
>> + * Called with interrupts disabled on the cpu
>
>So why are you handing in the (undocumented) cpu argument if its called on
>that cpu anyway?
>
Oh, my comment is very misleading. The function may be called from any
CPU for any other CPU. It should be more like "Called when the
interrupts are disabled on the CPU". I guess that doesn't make sense
either. I will remove this comment.

Thanks,
Lina

>> + */
>> +ktime_t tick_nohz_get_next_wakeup(int cpu)
>> +{
>> +	struct clock_event_device *dev =
>> +			per_cpu(tick_cpu_device.evtdev, cpu);
>> +
>> +	return dev->next_event;
>
>Then this becomes
>
>     return __this_cpu_read(tick_cpu_device.evtdev)->nextevt;
>
>Thanks,
>
>	tglx

Re: [PATCH 00/14] PM: SoC idle support using PM domains

[Lina Iyer]

On Tue, Jul 26 2016 at 16:08 -0600, Kevin Hilman wrote:
>Lina Iyer <lina.iyer@linaro.org> writes:
>
>> Hi all,
>>
>> Changes since RFC-v3:
>> - Reorganize the patches. Documentations have their own patch.
>> - Moved code around with PSCI OS initiated so they would not have compiler
>>   errors in other configuration.
>> - Minor bug fixes with genpd power_on functionality.
>> - Rebased on top of 4.7-rc1
>
>This is looking good.  I've had a quick look through this, as well as
>tested it on apq8016-sbc (dragon 410c.)
>
Thanks Kevin.


>Seems the main thing left to resolve is the DT description.
>
I am inclining to have the DT description point to arm,idle-state as
suggested by Mark. I will change this in my next revision.

Thanks for your time.

Lina

[PATCH 00/14] PM: SoC idle support using PM domains

[Lina Iyer]

On Tue, Jul 26 2016 at 16:08 -0600, Kevin Hilman wrote:
>Lina Iyer <lina.iyer@linaro.org> writes:
>
>> Hi all,
>>
>> Changes since RFC-v3:
>> - Reorganize the patches. Documentations have their own patch.
>> - Moved code around with PSCI OS initiated so they would not have compiler
>>   errors in other configuration.
>> - Minor bug fixes with genpd power_on functionality.
>> - Rebased on top of 4.7-rc1
>
>This is looking good.  I've had a quick look through this, as well as
>tested it on apq8016-sbc (dragon 410c.)
>
Thanks Kevin.


>Seems the main thing left to resolve is the DT description.
>
I am inclining to have the DT description point to arm,idle-state as
suggested by Mark. I will change this in my next revision.

Thanks for your time.

Lina