linux-stable/include/linux/pm_domain.h
Lina Iyer d716f4798f PM / Domains: Support IRQ safe PM domains
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.

Signed-off-by: Lina Iyer <lina.iyer@linaro.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-10-21 22:20:56 +02:00

283 lines
8.2 KiB
C

/*
* pm_domain.h - Definitions and headers related to device power domains.
*
* Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
*
* This file is released under the GPLv2.
*/
#ifndef _LINUX_PM_DOMAIN_H
#define _LINUX_PM_DOMAIN_H
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/pm.h>
#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 */
enum gpd_status {
GPD_STATE_ACTIVE = 0, /* PM domain is active */
GPD_STATE_POWER_OFF, /* PM domain is off */
};
struct dev_power_governor {
bool (*power_down_ok)(struct dev_pm_domain *domain);
bool (*suspend_ok)(struct device *dev);
};
struct gpd_dev_ops {
int (*start)(struct device *dev);
int (*stop)(struct device *dev);
bool (*active_wakeup)(struct device *dev);
};
struct genpd_power_state {
s64 power_off_latency_ns;
s64 power_on_latency_ns;
s64 residency_ns;
struct fwnode_handle *fwnode;
};
struct genpd_lock_ops;
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 dev_power_governor *gov;
struct work_struct power_off_work;
struct fwnode_handle *provider; /* Identity of the domain provider */
bool has_provider;
const char *name;
atomic_t sd_count; /* Number of subdomains with power "on" */
enum gpd_status status; /* Current state of the domain */
unsigned int device_count; /* Number of devices */
unsigned int suspended_count; /* System suspend device counter */
unsigned int prepared_count; /* Suspend counter of prepared devices */
int (*power_off)(struct generic_pm_domain *domain);
int (*power_on)(struct generic_pm_domain *domain);
struct gpd_dev_ops dev_ops;
s64 max_off_time_ns; /* Maximum allowed "suspended" time. */
bool max_off_time_changed;
bool cached_power_down_ok;
int (*attach_dev)(struct generic_pm_domain *domain,
struct device *dev);
void (*detach_dev)(struct generic_pm_domain *domain,
struct device *dev);
unsigned int flags; /* Bit field of configs for genpd */
struct genpd_power_state *states;
unsigned int state_count; /* number of states */
unsigned int state_idx; /* state that genpd will go to when off */
void *free; /* Free the state that was allocated for default */
const struct genpd_lock_ops *lock_ops;
union {
struct mutex mlock;
struct {
spinlock_t slock;
unsigned long lock_flags;
};
};
};
static inline struct generic_pm_domain *pd_to_genpd(struct dev_pm_domain *pd)
{
return container_of(pd, struct generic_pm_domain, domain);
}
struct gpd_link {
struct generic_pm_domain *master;
struct list_head master_node;
struct generic_pm_domain *slave;
struct list_head slave_node;
};
struct gpd_timing_data {
s64 suspend_latency_ns;
s64 resume_latency_ns;
s64 effective_constraint_ns;
bool constraint_changed;
bool cached_suspend_ok;
};
struct pm_domain_data {
struct list_head list_node;
struct device *dev;
};
struct generic_pm_domain_data {
struct pm_domain_data base;
struct gpd_timing_data td;
struct notifier_block nb;
};
#ifdef CONFIG_PM_GENERIC_DOMAINS
static inline struct generic_pm_domain_data *to_gpd_data(struct pm_domain_data *pdd)
{
return container_of(pdd, struct generic_pm_domain_data, base);
}
static inline struct generic_pm_domain_data *dev_gpd_data(struct device *dev)
{
return to_gpd_data(dev->power.subsys_data->domain_data);
}
extern int __pm_genpd_add_device(struct generic_pm_domain *genpd,
struct device *dev,
struct gpd_timing_data *td);
extern int pm_genpd_remove_device(struct generic_pm_domain *genpd,
struct device *dev);
extern int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
struct generic_pm_domain *new_subdomain);
extern int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
struct generic_pm_domain *target);
extern int pm_genpd_init(struct generic_pm_domain *genpd,
struct dev_power_governor *gov, bool is_off);
extern int pm_genpd_remove(struct generic_pm_domain *genpd);
extern struct dev_power_governor simple_qos_governor;
extern struct dev_power_governor pm_domain_always_on_gov;
#else
static inline struct generic_pm_domain_data *dev_gpd_data(struct device *dev)
{
return ERR_PTR(-ENOSYS);
}
static inline int __pm_genpd_add_device(struct generic_pm_domain *genpd,
struct device *dev,
struct gpd_timing_data *td)
{
return -ENOSYS;
}
static inline int pm_genpd_remove_device(struct generic_pm_domain *genpd,
struct device *dev)
{
return -ENOSYS;
}
static inline int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
struct generic_pm_domain *new_sd)
{
return -ENOSYS;
}
static inline int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
struct generic_pm_domain *target)
{
return -ENOSYS;
}
static inline int pm_genpd_init(struct generic_pm_domain *genpd,
struct dev_power_governor *gov, bool is_off)
{
return -ENOSYS;
}
static inline int pm_genpd_remove(struct generic_pm_domain *genpd)
{
return -ENOTSUPP;
}
#endif
static inline int pm_genpd_add_device(struct generic_pm_domain *genpd,
struct device *dev)
{
return __pm_genpd_add_device(genpd, dev, NULL);
}
#ifdef CONFIG_PM_GENERIC_DOMAINS_SLEEP
extern void pm_genpd_syscore_poweroff(struct device *dev);
extern void pm_genpd_syscore_poweron(struct device *dev);
#else
static inline void pm_genpd_syscore_poweroff(struct device *dev) {}
static inline void pm_genpd_syscore_poweron(struct device *dev) {}
#endif
/* OF PM domain providers */
struct of_device_id;
struct genpd_onecell_data {
struct generic_pm_domain **domains;
unsigned int num_domains;
};
#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
int of_genpd_add_provider_simple(struct device_node *np,
struct generic_pm_domain *genpd);
int of_genpd_add_provider_onecell(struct device_node *np,
struct genpd_onecell_data *data);
void of_genpd_del_provider(struct device_node *np);
extern int of_genpd_add_device(struct of_phandle_args *args,
struct device *dev);
extern int of_genpd_add_subdomain(struct of_phandle_args *parent,
struct of_phandle_args *new_subdomain);
extern struct generic_pm_domain *of_genpd_remove_last(struct device_node *np);
extern int of_genpd_parse_idle_states(struct device_node *dn,
struct genpd_power_state **states, int *n);
int genpd_dev_pm_attach(struct device *dev);
#else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
static inline int of_genpd_add_provider_simple(struct device_node *np,
struct generic_pm_domain *genpd)
{
return -ENOTSUPP;
}
static inline int of_genpd_add_provider_onecell(struct device_node *np,
struct genpd_onecell_data *data)
{
return -ENOTSUPP;
}
static inline void of_genpd_del_provider(struct device_node *np) {}
static inline int of_genpd_add_device(struct of_phandle_args *args,
struct device *dev)
{
return -ENODEV;
}
static inline int of_genpd_add_subdomain(struct of_phandle_args *parent,
struct of_phandle_args *new_subdomain)
{
return -ENODEV;
}
static inline int of_genpd_parse_idle_states(struct device_node *dn,
struct genpd_power_state **states, int *n)
{
return -ENODEV;
}
static inline int genpd_dev_pm_attach(struct device *dev)
{
return -ENODEV;
}
static inline
struct generic_pm_domain *of_genpd_remove_last(struct device_node *np)
{
return ERR_PTR(-ENOTSUPP);
}
#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
#ifdef CONFIG_PM
extern int dev_pm_domain_attach(struct device *dev, bool power_on);
extern void dev_pm_domain_detach(struct device *dev, bool power_off);
extern 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)
{
return -ENODEV;
}
static inline void dev_pm_domain_detach(struct device *dev, bool power_off) {}
static inline void dev_pm_domain_set(struct device *dev,
struct dev_pm_domain *pd) {}
#endif
#endif /* _LINUX_PM_DOMAIN_H */