PM / Domains: Support for generic I/O PM domains (v8)

Introduce common headers, helper functions and callbacks allowing
platforms to use simple generic power domains for runtime power
management.

Introduce struct generic_pm_domain to be used for representing
power domains that each contain a number of devices and may be
parent domains or subdomains with respect to other power domains.
Among other things, this structure includes callbacks to be
provided by platforms for performing specific tasks related to
power management (i.e. ->stop_device() may disable a device's
clocks, while ->start_device() may enable them, ->power_off() is
supposed to remove power from the entire power domain
and ->power_on() is supposed to restore it).

Introduce functions that can be used as power domain runtime PM
callbacks, pm_genpd_runtime_suspend() and pm_genpd_runtime_resume(),
as well as helper functions for the initialization of a power
domain represented by a struct generic_power_domain object,
adding a device to or removing a device from it and adding or
removing subdomains.

Introduce configuration option CONFIG_PM_GENERIC_DOMAINS to be
selected by the platforms that want to use the new code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Reviewed-by: Kevin Hilman <khilman@ti.com>

drivers/base/power/Makefile

@@ -3,6 +3,7 @@ obj-$(CONFIG_PM_SLEEP)	+= main.o wakeup.o
 obj-$(CONFIG_PM_RUNTIME)	+= runtime.o
 obj-$(CONFIG_PM_TRACE_RTC)	+= trace.o
 obj-$(CONFIG_PM_OPP)	+= opp.o
+obj-$(CONFIG_PM_GENERIC_DOMAINS)	+=  domain.o
 obj-$(CONFIG_HAVE_CLK)	+= clock_ops.o
 
 ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
\ No newline at end of file

include/linux/pm_domain.h

+/*
+ * 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>
+
+struct dev_power_governor {
+	bool (*power_down_ok)(struct dev_pm_domain *domain);
+};
+
+struct generic_pm_domain {
+	struct dev_pm_domain domain;	/* PM domain operations */
+	struct list_head sd_node;	/* Node in the parent's subdomain list */
+	struct generic_pm_domain *parent;	/* Parent PM domain */
+	struct list_head sd_list;	/* List of dubdomains */
+	struct list_head dev_list;	/* List of devices */
+	struct mutex lock;
+	struct dev_power_governor *gov;
+	struct work_struct power_off_work;
+	unsigned int in_progress;	/* Number of devices being suspended now */
+	unsigned int sd_count;	/* Number of subdomains with power "on" */
+	bool power_is_off;	/* Whether or not power has been removed */
+	int (*power_off)(struct generic_pm_domain *domain);
+	int (*power_on)(struct generic_pm_domain *domain);
+	int (*start_device)(struct device *dev);
+	int (*stop_device)(struct device *dev);
+};
+
+struct dev_list_entry {
+	struct list_head node;
+	struct device *dev;
+	bool need_restore;
+};
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS
+extern int pm_genpd_add_device(struct generic_pm_domain *genpd,
+			       struct device *dev);
+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 void pm_genpd_init(struct generic_pm_domain *genpd,
+			  struct dev_power_governor *gov, bool is_off);
+#else
+static inline int pm_genpd_add_device(struct generic_pm_domain *genpd,
+				      struct device *dev)
+{
+	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 void pm_genpd_init(struct generic_pm_domain *genpd,
+				 struct dev_power_governor *gov, bool is_off) {}
+#endif
+
+#endif /* _LINUX_PM_DOMAIN_H */

kernel/power/Kconfig

@@ -227,3 +227,7 @@ config PM_OPP
 config PM_RUNTIME_CLK
 	def_bool y
 	depends on PM_RUNTIME && HAVE_CLK
+
+config PM_GENERIC_DOMAINS
+	bool
+	depends on PM