From 25cb20a212a1f989385dfe23230817e69c62bee5 Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Wed, 16 Oct 2019 16:57:53 +0200 Subject: PM / OPP: Support adjusting OPP voltages at runtime On some SoCs the Adaptive Voltage Scaling (AVS) technique is employed to optimize the operating voltage of a device. At a given frequency, the hardware monitors dynamic factors and either makes a suggestion for how much to adjust a voltage for the current frequency, or it automatically adjusts the voltage without software intervention. Add an API to the OPP library for the former case, so that AVS type devices can update the voltages for an OPP when the hardware determines the voltage should change. The assumption is that drivers like CPUfreq or devfreq will register for the OPP notifiers and adjust the voltage according to suggestions that AVS makes. This patch is derived from [1] submitted by Stephen. [1] https://lore.kernel.org/patchwork/patch/599279/ Signed-off-by: Stephen Boyd [Roger Lu: Changed to rcu less implementation] Signed-off-by: Roger Lu [s.nawrocki@samsung.com: added handling of OPP min/max voltage] Signed-off-by: Sylwester Nawrocki Signed-off-by: Viresh Kumar --- include/linux/pm_opp.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h index b8197ab014f2..747861816f4f 100644 --- a/include/linux/pm_opp.h +++ b/include/linux/pm_opp.h @@ -22,6 +22,7 @@ struct opp_table; enum dev_pm_opp_event { OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE, + OPP_EVENT_ADJUST_VOLTAGE, }; /** @@ -113,6 +114,10 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, void dev_pm_opp_remove(struct device *dev, unsigned long freq); void dev_pm_opp_remove_all_dynamic(struct device *dev); +int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq, + unsigned long u_volt, unsigned long u_volt_min, + unsigned long u_volt_max); + int dev_pm_opp_enable(struct device *dev, unsigned long freq); int dev_pm_opp_disable(struct device *dev, unsigned long freq); @@ -242,6 +247,14 @@ static inline void dev_pm_opp_remove_all_dynamic(struct device *dev) { } +static inline int +dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq, + unsigned long u_volt, unsigned long u_volt_min, + unsigned long u_volt_max) +{ + return 0; +} + static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq) { return 0; -- cgit v1.2.3 From ca765a8cfe0c78bfa47b9d67121f4e342d4b4512 Mon Sep 17 00:00:00 2001 From: Ulf Hansson Date: Wed, 16 Oct 2019 15:16:03 +0200 Subject: PM / Domains: Introduce dev_pm_domain_start() For a subsystem/driver that either doesn't support runtime PM or makes use of pm_runtime_set_active() during ->probe(), may try to access its device when probing, even if it may not be fully powered on from the PM domain's point of view. This may be the case when the used PM domain is a genpd provider, that implements genpd's ->start|stop() device callbacks. There are cases where the subsystem/driver managed to avoid the above problem, simply by calling pm_runtime_enable() and pm_runtime_get_sync() during ->probe(). However, this approach comes with a drawback, especially if the subsystem/driver implements a ->runtime_resume() callback. More precisely, the subsystem/driver then needs to use a device flag, which is checked in its ->runtime_resume() callback, as to avoid powering on its resources the first time the callback is invoked. This is needed because the subsystem/driver has already powered on the resources for the device, during ->probe() and before it called pm_runtime_get_sync(). In a way to avoid this boilerplate code and the inefficient check for "if (first_time_suspend)" in the ->runtime_resume() callback for these subsystems/drivers, let's introduce and export a dev_pm_domain_start() function, that may be called during ->probe() instead. Moreover, let the dev_pm_domain_start() invoke an optional ->start() callback, added to the struct dev_pm_domain, as to allow a PM domain specific implementation. Signed-off-by: Ulf Hansson Signed-off-by: Rafael J. Wysocki --- include/linux/pm.h | 2 ++ include/linux/pm_domain.h | 5 +++++ 2 files changed, 7 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pm.h b/include/linux/pm.h index 4c441be03079..e057d1fa2469 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -637,6 +637,7 @@ extern void dev_pm_put_subsys_data(struct device *dev); * struct dev_pm_domain - power management domain representation. * * @ops: Power management operations associated with this domain. + * @start: Called when a user needs to start the device via the domain. * @detach: Called when removing a device from the domain. * @activate: Called before executing probe routines for bus types and drivers. * @sync: Called after successful driver probe. @@ -648,6 +649,7 @@ extern void dev_pm_put_subsys_data(struct device *dev); */ struct dev_pm_domain { struct dev_pm_ops ops; + int (*start)(struct device *dev); void (*detach)(struct device *dev, bool power_off); int (*activate)(struct device *dev); void (*sync)(struct device *dev); diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index baf02ff91a31..5a31c711b896 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -366,6 +366,7 @@ struct device *dev_pm_domain_attach_by_id(struct device *dev, struct device *dev_pm_domain_attach_by_name(struct device *dev, const char *name); void dev_pm_domain_detach(struct device *dev, bool power_off); +int dev_pm_domain_start(struct device *dev); void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd); #else static inline int dev_pm_domain_attach(struct device *dev, bool power_on) @@ -383,6 +384,10 @@ static inline struct device *dev_pm_domain_attach_by_name(struct device *dev, return NULL; } static inline void dev_pm_domain_detach(struct device *dev, bool power_off) {} +static inline int dev_pm_domain_start(struct device *dev) +{ + return 0; +} static inline void dev_pm_domain_set(struct device *dev, struct dev_pm_domain *pd) {} #endif -- cgit v1.2.3