17b75eca76
Currently, the .start_device() and .stop_device() callbacks from struct generic_pm_domain() as well as the device drivers' runtime PM callbacks used by the generic PM domains code are executed under the generic PM domain lock. This, unfortunately, is prone to deadlocks, for example if a device and its parent are boths members of the same PM domain. For this reason, it would be better if the PM domains code didn't execute device callbacks under the lock. Rework the locking in the generic PM domains code so that the lock is dropped for the execution of device callbacks. To this end, introduce PM domains states reflecting the current status of a PM domain and such that the PM domain lock cannot be acquired if the status is GPD_STATE_BUSY. Make threads attempting to acquire a PM domain's lock wait until the status changes to either GPD_STATE_ACTIVE or GPD_STATE_POWER_OFF. This change by itself doesn't fix the deadlock problem mentioned above, but the mechanism introduced by it will be used for for this purpose by a subsequent patch. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
101 lines
3.2 KiB
C
101 lines
3.2 KiB
C
/*
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* pm_domain.h - Definitions and headers related to device power domains.
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*
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* Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
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*
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* This file is released under the GPLv2.
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*/
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#ifndef _LINUX_PM_DOMAIN_H
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#define _LINUX_PM_DOMAIN_H
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#include <linux/device.h>
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enum gpd_status {
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GPD_STATE_ACTIVE = 0, /* PM domain is active */
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GPD_STATE_BUSY, /* Something is happening to the PM domain */
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GPD_STATE_POWER_OFF, /* PM domain is off */
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};
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struct dev_power_governor {
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bool (*power_down_ok)(struct dev_pm_domain *domain);
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};
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struct generic_pm_domain {
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struct dev_pm_domain domain; /* PM domain operations */
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struct list_head sd_node; /* Node in the parent's subdomain list */
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struct generic_pm_domain *parent; /* Parent PM domain */
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struct list_head sd_list; /* List of dubdomains */
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struct list_head dev_list; /* List of devices */
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struct mutex lock;
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struct dev_power_governor *gov;
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struct work_struct power_off_work;
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unsigned int in_progress; /* Number of devices being suspended now */
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unsigned int sd_count; /* Number of subdomains with power "on" */
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enum gpd_status status; /* Current state of the domain */
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wait_queue_head_t status_wait_queue;
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unsigned int device_count; /* Number of devices */
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unsigned int suspended_count; /* System suspend device counter */
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unsigned int prepared_count; /* Suspend counter of prepared devices */
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bool suspend_power_off; /* Power status before system suspend */
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int (*power_off)(struct generic_pm_domain *domain);
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int (*power_on)(struct generic_pm_domain *domain);
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int (*start_device)(struct device *dev);
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int (*stop_device)(struct device *dev);
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bool (*active_wakeup)(struct device *dev);
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};
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static inline struct generic_pm_domain *pd_to_genpd(struct dev_pm_domain *pd)
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{
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return container_of(pd, struct generic_pm_domain, domain);
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}
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struct dev_list_entry {
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struct list_head node;
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struct device *dev;
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bool need_restore;
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};
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#ifdef CONFIG_PM_GENERIC_DOMAINS
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extern int pm_genpd_add_device(struct generic_pm_domain *genpd,
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struct device *dev);
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extern int pm_genpd_remove_device(struct generic_pm_domain *genpd,
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struct device *dev);
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extern int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
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struct generic_pm_domain *new_subdomain);
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extern int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
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struct generic_pm_domain *target);
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extern void pm_genpd_init(struct generic_pm_domain *genpd,
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struct dev_power_governor *gov, bool is_off);
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extern int pm_genpd_poweron(struct generic_pm_domain *genpd);
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#else
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static inline int pm_genpd_add_device(struct generic_pm_domain *genpd,
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struct device *dev)
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{
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return -ENOSYS;
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}
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static inline int pm_genpd_remove_device(struct generic_pm_domain *genpd,
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struct device *dev)
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{
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return -ENOSYS;
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}
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static inline int pm_genpd_add_subdomain(struct generic_pm_domain *genpd,
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struct generic_pm_domain *new_sd)
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{
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return -ENOSYS;
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}
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static inline int pm_genpd_remove_subdomain(struct generic_pm_domain *genpd,
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struct generic_pm_domain *target)
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{
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return -ENOSYS;
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}
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static inline void pm_genpd_init(struct generic_pm_domain *genpd,
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struct dev_power_governor *gov, bool is_off) {}
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static inline int pm_genpd_poweron(struct generic_pm_domain *genpd)
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{
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return -ENOSYS;
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}
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#endif
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#endif /* _LINUX_PM_DOMAIN_H */
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