[PATCH v6 0/3] pmdomain: ti_sci: collect and send low-power mode constraints

[PATCH v6 0/3] pmdomain: ti_sci: collect and send low-power mode constraints

[Kevin Hilman]

The latest (10.x) version of the firmware for the PM co-processor (aka
device manager, or DM) adds support for a "managed" mode, where the DM
firmware will select the specific low power state which is entered
when Linux requests a system-wide suspend.

In this mode, the DM will always attempt the deepest low-power state
available for the SoC.

However, Linux (or OSes running on other cores) may want to constrain
the DM for certain use cases.  For example, the deepest state may have
a wakeup/resume latency that is too long for certain use cases.  Or,
some wakeup-capable devices may potentially be powered off in deep
low-power states, but if one of those devices is enabled as a wakeup
source, it should not be powered off.

These kinds of constraints are are already known in Linux by the use
of existing APIs such as per-device PM QoS and device wakeup APIs, but
now we need to communicate these constraints to the DM.

For TI SoCs with TI SCI support, all DM-managed devices will be
connected to a TI SCI PM domain.  So the goal of this series is to use
the PM domain driver for TI SCI devices to collect constraints, and
communicate them to the DM via the new TI SCI APIs.

This is all managed by TI SCI PM domain code.  No new APIs are needed
by Linux drivers.  Any device that is managed by TI SCI will be
checked for QoS constraints or wakeup capability and the constraints
will be collected and sent to the DM.

This series depends on the support for the new TI SCI APIs (v10) and
was also tested with this series to update 8250_omap serial support
for AM62x[2].

[1] https://lore.kernel.org/all/20240801195422.2296347-1-msp@baylibre.com
[2] https://lore.kernel.org/all/20240807141227.1093006-1-msp@baylibre.com/

Signed-off-by: Kevin Hilman <khilman@baylibre.com>
---
Changes in v6:
- fix build warning on arm32 when building with W=1 and CONFIG_PM_SLEEP=n
- rebase onto v6.13-rc1
- fix latency units: convert usecs (PM QoS) to msecs (TI SCI)
- all dependencies are now merged in v6.13-rc1
- Link to v5: https://lore.kernel.org/r/20241101-lpm-v6-10-constraints-pmdomain-v5-0-3011aa04622f@baylibre.com

Changes in v5:
- fix build error when CONFIG_PM_SLEEP not defined
- Link to v4: https://lore.kernel.org/r/20240906-lpm-v6-10-constraints-pmdomain-v4-0-4055557fafbc@baylibre.com

Changes in v4:
- fixed missing return in wakeirq error path
- updated trailers with reviewed & tested tags
- Link to v3: https://lore.kernel.org/r/20240905-lpm-v6-10-constraints-pmdomain-v3-0-e359cbb39654@baylibre.com

Changes in v3:
- change latency set functions to static void
- Link to v2: https://lore.kernel.org/r/20240819-lpm-v6-10-constraints-pmdomain-v2-0-461325a6008f@baylibre.com

Changes in v2:
- To simplify this version a bit, drop the pmdomain ->power_off()
  changes.  Constraints only sent during ->suspend() path.  The pmdomain
  path was an optimization that may be added back later.
- With the above simplification, drop the extra state variables that
  had been added to keep track of constraint status.
- Link to v1: https://lore.kernel.org/r/20240805-lpm-v6-10-constraints-pmdomain-v1-0-d186b68ded4c@baylibre.com

---
Kevin Hilman (3):
      pmdomain: ti_sci: add per-device latency constraint management
      pmdomain: ti_sci: add wakeup constraint management
      pmdomain: ti_sci: handle wake IRQs for IO daisy chain wakeups

 drivers/pmdomain/ti/ti_sci_pm_domains.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
---
base-commit: cbc4912199deab59fdbd830b115d81941d0add46
change-id: 20240802-lpm-v6-10-constraints-pmdomain-f33df5aef449

Best regards,
-- 
Kevin Hilman <khilman@baylibre.com>

[PATCH v6 1/3] pmdomain: ti_sci: add per-device latency constraint management

[Kevin Hilman]

For each device in a TI SCI PM domain, check whether the device has
any resume latency constraints set via per-device PM QoS.  If
constraints are set, send them to DM via the new SCI constraints API.

Checking for constraints happen for each device before system-wide
suspend (via ->suspend() hook.)

An important detail here is that the PM domain driver inserts itself
into the path of both the ->suspend() and ->resume() hook path
of *all* devices in the PM domain.  This allows generic PM domain code
to handle the constraint management and communication with TI SCI.

Further, this allows device drivers to use existing PM QoS APIs to
add/update constraints.

DM firmware clears constraints during its resume, so Linux has
to check/update/send constraints each time system suspends.

Also note that the PM QoS framework uses usecs as the units for
latency whereas the TI SCI firmware uses msecs, so a conversion is
needed before passing to TI SCI.

Co-developed-by: Vibhore Vardhan <vibhore@ti.com>
Signed-off-by: Vibhore Vardhan <vibhore@ti.com>
Reviewed-by: Markus Schneider-Pargmann <msp@baylibre.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
---
 drivers/pmdomain/ti/ti_sci_pm_domains.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/drivers/pmdomain/ti/ti_sci_pm_domains.c b/drivers/pmdomain/ti/ti_sci_pm_domains.c
index 0e4bd749d067309654307484c5bb98711bf06daf..963fe1901c959197d5d8b5d34fd8420dfb180087 100644
--- a/drivers/pmdomain/ti/ti_sci_pm_domains.c
+++ b/drivers/pmdomain/ti/ti_sci_pm_domains.c
@@ -13,6 +13,8 @@
 #include <linux/platform_device.h>
 #include <linux/pm_domain.h>
 #include <linux/slab.h>
+#include <linux/pm_qos.h>
+#include <linux/pm_runtime.h>
 #include <linux/soc/ti/ti_sci_protocol.h>
 #include <dt-bindings/soc/ti,sci_pm_domain.h>
 
@@ -51,6 +53,32 @@ struct ti_sci_pm_domain {
 
 #define genpd_to_ti_sci_pd(gpd) container_of(gpd, struct ti_sci_pm_domain, pd)
 
+static inline bool ti_sci_pd_is_valid_constraint(s32 val)
+{
+	return val != PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static void ti_sci_pd_set_lat_constraint(struct device *dev, s32 val)
+{
+	struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain);
+	struct ti_sci_pm_domain *pd = genpd_to_ti_sci_pd(genpd);
+	const struct ti_sci_handle *ti_sci = pd->parent->ti_sci;
+	u16 val_ms;
+	int ret;
+
+	/* PM QoS latency unit is usecs, TI SCI uses msecs */
+	val_ms = val / USEC_PER_MSEC;
+	ret = ti_sci->ops.pm_ops.set_latency_constraint(ti_sci, val_ms, TISCI_MSG_CONSTRAINT_SET);
+	if (ret)
+		dev_err(dev, "ti_sci_pd: set latency constraint failed: ret=%d\n",
+			ret);
+	else
+		dev_dbg(dev, "ti_sci_pd: ID:%d set latency constraint %d\n",
+			pd->idx, val);
+}
+#endif
+
 /*
  * ti_sci_pd_power_off(): genpd power down hook
  * @domain: pointer to the powerdomain to power off
@@ -79,6 +107,26 @@ static int ti_sci_pd_power_on(struct generic_pm_domain *domain)
 		return ti_sci->ops.dev_ops.get_device(ti_sci, pd->idx);
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int ti_sci_pd_suspend(struct device *dev)
+{
+	int ret;
+	s32 val;
+
+	ret = pm_generic_suspend(dev);
+	if (ret)
+		return ret;
+
+	val = dev_pm_qos_read_value(dev, DEV_PM_QOS_RESUME_LATENCY);
+	if (ti_sci_pd_is_valid_constraint(val))
+		ti_sci_pd_set_lat_constraint(dev, val);
+
+	return 0;
+}
+#else
+#define ti_sci_pd_suspend		NULL
+#endif
+
 /*
  * ti_sci_pd_xlate(): translation service for TI SCI genpds
  * @genpdspec: DT identification data for the genpd
@@ -182,6 +230,13 @@ static int ti_sci_pm_domain_probe(struct platform_device *pdev)
 				pd->pd.flags |= GENPD_FLAG_ACTIVE_WAKEUP;
 				pd->idx = args.args[0];
 				pd->parent = pd_provider;
+				/*
+				 * If SCI constraint functions are present, then firmware
+				 * supports the constraints API.
+				 */
+				if (pd_provider->ti_sci->ops.pm_ops.set_device_constraint &&
+				    pd_provider->ti_sci->ops.pm_ops.set_latency_constraint)
+					pd->pd.domain.ops.suspend = ti_sci_pd_suspend;
 
 				pm_genpd_init(&pd->pd, NULL, true);
 

-- 
2.46.2

[PATCH v6 2/3] pmdomain: ti_sci: add wakeup constraint management

[Kevin Hilman]

During system-wide suspend, check all devices connected to PM domain
to see if they are wakeup-enabled.  If so, set a TI SCI device
constraint.

Note: DM firmware clears all constraints on resume.

Co-developed-by: Vibhore Vardhan <vibhore@ti.com>
Signed-off-by: Vibhore Vardhan <vibhore@ti.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
---
 drivers/pmdomain/ti/ti_sci_pm_domains.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/pmdomain/ti/ti_sci_pm_domains.c b/drivers/pmdomain/ti/ti_sci_pm_domains.c
index 963fe1901c959197d5d8b5d34fd8420dfb180087..587961519dcc9e13c32efe76cdaf801281f72f67 100644
--- a/drivers/pmdomain/ti/ti_sci_pm_domains.c
+++ b/drivers/pmdomain/ti/ti_sci_pm_domains.c
@@ -79,6 +79,21 @@ static void ti_sci_pd_set_lat_constraint(struct device *dev, s32 val)
 }
 #endif
 
+static inline void ti_sci_pd_set_wkup_constraint(struct device *dev)
+{
+	struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain);
+	struct ti_sci_pm_domain *pd = genpd_to_ti_sci_pd(genpd);
+	const struct ti_sci_handle *ti_sci = pd->parent->ti_sci;
+	int ret;
+
+	if (device_may_wakeup(dev)) {
+		ret = ti_sci->ops.pm_ops.set_device_constraint(ti_sci, pd->idx,
+							       TISCI_MSG_CONSTRAINT_SET);
+		if (!ret)
+			dev_dbg(dev, "ti_sci_pd: ID:%d set device constraint.\n", pd->idx);
+	}
+}
+
 /*
  * ti_sci_pd_power_off(): genpd power down hook
  * @domain: pointer to the powerdomain to power off
@@ -121,6 +136,8 @@ static int ti_sci_pd_suspend(struct device *dev)
 	if (ti_sci_pd_is_valid_constraint(val))
 		ti_sci_pd_set_lat_constraint(dev, val);
 
+	ti_sci_pd_set_wkup_constraint(dev);
+
 	return 0;
 }
 #else

-- 
2.46.2

[PATCH v6 3/3] pmdomain: ti_sci: handle wake IRQs for IO daisy chain wakeups

[Kevin Hilman]

When a device supports IO daisy-chain wakeups, it uses a dedicated
wake IRQ.  Devices with IO daisy-chain wakeups enabled should not set
wakeup constraints since these can happen even from deep power states,
so should not prevent the DM from picking deep power states.

Wake IRQs are set with dev_pm_set_wake_irq() or
dev_pm_set_dedicated_wake_irq().  The latter is used by the serial
driver used on K3 platforms (drivers/tty/serial/8250/8250_omap.c)
when the interrupts-extended property is used to describe the
dedicated wakeup interrupt.

Detect these wake IRQs in the suspend path, and if set, skip sending
constraint.

Tested-by: Dhruva Gole <d-gole@ti.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
---
 drivers/pmdomain/ti/ti_sci_pm_domains.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/pmdomain/ti/ti_sci_pm_domains.c b/drivers/pmdomain/ti/ti_sci_pm_domains.c
index 587961519dcc9e13c32efe76cdaf801281f72f67..3fb78343d4388a7087dab5061c1127586968ef19 100644
--- a/drivers/pmdomain/ti/ti_sci_pm_domains.c
+++ b/drivers/pmdomain/ti/ti_sci_pm_domains.c
@@ -87,6 +87,15 @@ static inline void ti_sci_pd_set_wkup_constraint(struct device *dev)
 	int ret;
 
 	if (device_may_wakeup(dev)) {
+		/*
+		 * If device can wakeup using IO daisy chain wakeups,
+		 * we do not want to set a constraint.
+		 */
+		if (dev->power.wakeirq) {
+			dev_dbg(dev, "%s: has wake IRQ, not setting constraints\n", __func__);
+			return;
+		}
+
 		ret = ti_sci->ops.pm_ops.set_device_constraint(ti_sci, pd->idx,
 							       TISCI_MSG_CONSTRAINT_SET);
 		if (!ret)

-- 
2.46.2

Re: [PATCH v6 1/3] pmdomain: ti_sci: add per-device latency constraint management

[Dhruva Gole]

On Dec 06, 2024 at 14:12:50 -0800, Kevin Hilman wrote:
> For each device in a TI SCI PM domain, check whether the device has
> any resume latency constraints set via per-device PM QoS.  If
> constraints are set, send them to DM via the new SCI constraints API.
> 
> Checking for constraints happen for each device before system-wide
> suspend (via ->suspend() hook.)
> 
> An important detail here is that the PM domain driver inserts itself
> into the path of both the ->suspend() and ->resume() hook path
> of *all* devices in the PM domain.  This allows generic PM domain code
> to handle the constraint management and communication with TI SCI.
> 
> Further, this allows device drivers to use existing PM QoS APIs to
> add/update constraints.
> 
> DM firmware clears constraints during its resume, so Linux has
> to check/update/send constraints each time system suspends.
> 
> Also note that the PM QoS framework uses usecs as the units for
> latency whereas the TI SCI firmware uses msecs, so a conversion is
> needed before passing to TI SCI.
> 
> Co-developed-by: Vibhore Vardhan <vibhore@ti.com>
> Signed-off-by: Vibhore Vardhan <vibhore@ti.com>
> Reviewed-by: Markus Schneider-Pargmann <msp@baylibre.com>
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Tested-by: Dhruva Gole <d-gole@ti.com>
> Signed-off-by: Kevin Hilman <khilman@baylibre.com>
> ---
>  drivers/pmdomain/ti/ti_sci_pm_domains.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 55 insertions(+)
> 
> diff --git a/drivers/pmdomain/ti/ti_sci_pm_domains.c b/drivers/pmdomain/ti/ti_sci_pm_domains.c
> index 0e4bd749d067309654307484c5bb98711bf06daf..963fe1901c959197d5d8b5d34fd8420dfb180087 100644
> --- a/drivers/pmdomain/ti/ti_sci_pm_domains.c
> +++ b/drivers/pmdomain/ti/ti_sci_pm_domains.c
> @@ -13,6 +13,8 @@
>  #include <linux/platform_device.h>
>  #include <linux/pm_domain.h>
>  #include <linux/slab.h>
> +#include <linux/pm_qos.h>
> +#include <linux/pm_runtime.h>

nit: Do we not need to sort these includes alphabetically?

>  #include <linux/soc/ti/ti_sci_protocol.h>
>  #include <dt-bindings/soc/ti,sci_pm_domain.h>
>  
> @@ -51,6 +53,32 @@ struct ti_sci_pm_domain {
>  
>  #define genpd_to_ti_sci_pd(gpd) container_of(gpd, struct ti_sci_pm_domain, pd)
>  
> +static inline bool ti_sci_pd_is_valid_constraint(s32 val)
> +{
> +	return val != PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static void ti_sci_pd_set_lat_constraint(struct device *dev, s32 val)
> +{
> +	struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain);
> +	struct ti_sci_pm_domain *pd = genpd_to_ti_sci_pd(genpd);
> +	const struct ti_sci_handle *ti_sci = pd->parent->ti_sci;
> +	u16 val_ms;
> +	int ret;
> +
> +	/* PM QoS latency unit is usecs, TI SCI uses msecs */
> +	val_ms = val / USEC_PER_MSEC;
> +	ret = ti_sci->ops.pm_ops.set_latency_constraint(ti_sci, val_ms, TISCI_MSG_CONSTRAINT_SET);
> +	if (ret)
> +		dev_err(dev, "ti_sci_pd: set latency constraint failed: ret=%d\n",
> +			ret);
> +	else
> +		dev_dbg(dev, "ti_sci_pd: ID:%d set latency constraint %d\n",
> +			pd->idx, val);
> +}
> +#endif
> +
>  /*
>   * ti_sci_pd_power_off(): genpd power down hook
>   * @domain: pointer to the powerdomain to power off
> @@ -79,6 +107,26 @@ static int ti_sci_pd_power_on(struct generic_pm_domain *domain)
>  		return ti_sci->ops.dev_ops.get_device(ti_sci, pd->idx);
>  }
>  
> +#ifdef CONFIG_PM_SLEEP
> +static int ti_sci_pd_suspend(struct device *dev)
> +{
> +	int ret;
> +	s32 val;
> +
> +	ret = pm_generic_suspend(dev);
> +	if (ret)
> +		return ret;
> +
> +	val = dev_pm_qos_read_value(dev, DEV_PM_QOS_RESUME_LATENCY);
> +	if (ti_sci_pd_is_valid_constraint(val))
> +		ti_sci_pd_set_lat_constraint(dev, val);
> +
> +	return 0;
> +}
> +#else
> +#define ti_sci_pd_suspend		NULL
> +#endif
> +
>  /*
>   * ti_sci_pd_xlate(): translation service for TI SCI genpds
>   * @genpdspec: DT identification data for the genpd
> @@ -182,6 +230,13 @@ static int ti_sci_pm_domain_probe(struct platform_device *pdev)
>  				pd->pd.flags |= GENPD_FLAG_ACTIVE_WAKEUP;
>  				pd->idx = args.args[0];
>  				pd->parent = pd_provider;
> +				/*
> +				 * If SCI constraint functions are present, then firmware
> +				 * supports the constraints API.
> +				 */
> +				if (pd_provider->ti_sci->ops.pm_ops.set_device_constraint &&
> +				    pd_provider->ti_sci->ops.pm_ops.set_latency_constraint)
> +					pd->pd.domain.ops.suspend = ti_sci_pd_suspend;

Rest looks good.
Reviewed-by: Dhruva Gole <d-gole@ti.com>

-- 
Best regards,
Dhruva Gole
Texas Instruments Incorporated

Re: [PATCH v6 2/3] pmdomain: ti_sci: add wakeup constraint management

[Dhruva Gole]

On Dec 06, 2024 at 14:12:51 -0800, Kevin Hilman wrote:
> During system-wide suspend, check all devices connected to PM domain
> to see if they are wakeup-enabled.  If so, set a TI SCI device
> constraint.
> 
> Note: DM firmware clears all constraints on resume.
> 
> Co-developed-by: Vibhore Vardhan <vibhore@ti.com>
> Signed-off-by: Vibhore Vardhan <vibhore@ti.com>
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Tested-by: Dhruva Gole <d-gole@ti.com>
> Signed-off-by: Kevin Hilman <khilman@baylibre.com>
> ---

Reviewed-by: Dhruva Gole <d-gole@ti.com>


-- 
Best regards,
Dhruva Gole
Texas Instruments Incorporated

Re: [PATCH v6 3/3] pmdomain: ti_sci: handle wake IRQs for IO daisy chain wakeups

[Dhruva Gole]

On Dec 06, 2024 at 14:12:52 -0800, Kevin Hilman wrote:
> When a device supports IO daisy-chain wakeups, it uses a dedicated
> wake IRQ.  Devices with IO daisy-chain wakeups enabled should not set
> wakeup constraints since these can happen even from deep power states,
> so should not prevent the DM from picking deep power states.
> 
> Wake IRQs are set with dev_pm_set_wake_irq() or
> dev_pm_set_dedicated_wake_irq().  The latter is used by the serial
> driver used on K3 platforms (drivers/tty/serial/8250/8250_omap.c)
> when the interrupts-extended property is used to describe the
> dedicated wakeup interrupt.
> 
> Detect these wake IRQs in the suspend path, and if set, skip sending
> constraint.
> 
> Tested-by: Dhruva Gole <d-gole@ti.com>
> Signed-off-by: Kevin Hilman <khilman@baylibre.com>
> ---

Reviewed-by: Dhruva Gole <d-gole@ti.com>


-- 
Best regards,
Dhruva Gole
Texas Instruments Incorporated

Re: [PATCH v6 0/3] pmdomain: ti_sci: collect and send low-power mode constraints

[Ulf Hansson]

On Fri, 6 Dec 2024 at 23:13, Kevin Hilman <khilman@baylibre.com> wrote:
>
> The latest (10.x) version of the firmware for the PM co-processor (aka
> device manager, or DM) adds support for a "managed" mode, where the DM
> firmware will select the specific low power state which is entered
> when Linux requests a system-wide suspend.
>
> In this mode, the DM will always attempt the deepest low-power state
> available for the SoC.
>
> However, Linux (or OSes running on other cores) may want to constrain
> the DM for certain use cases.  For example, the deepest state may have
> a wakeup/resume latency that is too long for certain use cases.  Or,
> some wakeup-capable devices may potentially be powered off in deep
> low-power states, but if one of those devices is enabled as a wakeup
> source, it should not be powered off.
>
> These kinds of constraints are are already known in Linux by the use
> of existing APIs such as per-device PM QoS and device wakeup APIs, but
> now we need to communicate these constraints to the DM.
>
> For TI SoCs with TI SCI support, all DM-managed devices will be
> connected to a TI SCI PM domain.  So the goal of this series is to use
> the PM domain driver for TI SCI devices to collect constraints, and
> communicate them to the DM via the new TI SCI APIs.
>
> This is all managed by TI SCI PM domain code.  No new APIs are needed
> by Linux drivers.  Any device that is managed by TI SCI will be
> checked for QoS constraints or wakeup capability and the constraints
> will be collected and sent to the DM.
>
> This series depends on the support for the new TI SCI APIs (v10) and
> was also tested with this series to update 8250_omap serial support
> for AM62x[2].
>
> [1] https://lore.kernel.org/all/20240801195422.2296347-1-msp@baylibre.com
> [2] https://lore.kernel.org/all/20240807141227.1093006-1-msp@baylibre.com/
>
> Signed-off-by: Kevin Hilman <khilman@baylibre.com>
> ---
> Changes in v6:
> - fix build warning on arm32 when building with W=1 and CONFIG_PM_SLEEP=n
> - rebase onto v6.13-rc1
> - fix latency units: convert usecs (PM QoS) to msecs (TI SCI)
> - all dependencies are now merged in v6.13-rc1
> - Link to v5: https://lore.kernel.org/r/20241101-lpm-v6-10-constraints-pmdomain-v5-0-3011aa04622f@baylibre.com

v6 applied for next and by amending patch1 to deal with the sorting of
include files, thanks!

[...]

Kind regards
Uffe

Re: [PATCH v6 0/3] pmdomain: ti_sci: collect and send low-power mode constraints

[Kevin Hilman]

Ulf Hansson <ulf.hansson@linaro.org> writes:

> On Fri, 6 Dec 2024 at 23:13, Kevin Hilman <khilman@baylibre.com> wrote:
>>
>> The latest (10.x) version of the firmware for the PM co-processor (aka
>> device manager, or DM) adds support for a "managed" mode, where the DM
>> firmware will select the specific low power state which is entered
>> when Linux requests a system-wide suspend.
>>
>> In this mode, the DM will always attempt the deepest low-power state
>> available for the SoC.
>>
>> However, Linux (or OSes running on other cores) may want to constrain
>> the DM for certain use cases.  For example, the deepest state may have
>> a wakeup/resume latency that is too long for certain use cases.  Or,
>> some wakeup-capable devices may potentially be powered off in deep
>> low-power states, but if one of those devices is enabled as a wakeup
>> source, it should not be powered off.
>>
>> These kinds of constraints are are already known in Linux by the use
>> of existing APIs such as per-device PM QoS and device wakeup APIs, but
>> now we need to communicate these constraints to the DM.
>>
>> For TI SoCs with TI SCI support, all DM-managed devices will be
>> connected to a TI SCI PM domain.  So the goal of this series is to use
>> the PM domain driver for TI SCI devices to collect constraints, and
>> communicate them to the DM via the new TI SCI APIs.
>>
>> This is all managed by TI SCI PM domain code.  No new APIs are needed
>> by Linux drivers.  Any device that is managed by TI SCI will be
>> checked for QoS constraints or wakeup capability and the constraints
>> will be collected and sent to the DM.
>>
>> This series depends on the support for the new TI SCI APIs (v10) and
>> was also tested with this series to update 8250_omap serial support
>> for AM62x[2].
>>
>> [1] https://lore.kernel.org/all/20240801195422.2296347-1-msp@baylibre.com
>> [2] https://lore.kernel.org/all/20240807141227.1093006-1-msp@baylibre.com/
>>
>> Signed-off-by: Kevin Hilman <khilman@baylibre.com>
>> ---
>> Changes in v6:
>> - fix build warning on arm32 when building with W=1 and CONFIG_PM_SLEEP=n
>> - rebase onto v6.13-rc1
>> - fix latency units: convert usecs (PM QoS) to msecs (TI SCI)
>> - all dependencies are now merged in v6.13-rc1
>> - Link to v5: https://lore.kernel.org/r/20241101-lpm-v6-10-constraints-pmdomain-v5-0-3011aa04622f@baylibre.com
>
> v6 applied for next and by amending patch1 to deal with the sorting of
> include files, thanks!

Thank you for the fixuup.

Kevin