PM / Domains: Introduce "save/restore state" device callbacks
The current PM domains code uses device drivers' .runtime_suspend()
and .runtime_resume() callbacks as the "save device state" and
"restore device state" operations, which may not be appropriate in
general, because it forces drivers to assume that they always will
be used with generic PM domains. However, in theory, the same
hardware may be used in devices that don't belong to any PM
domain, in which case it would be necessary to add "fake" PM
domains to satisfy the above assumption. It also may be located in
a PM domain that's not handled with the help of the generic code.
To allow device drivers that may be used along with the generic PM
domains code of more flexibility, introduce new device callbacks,
.save_state() and .restore_state(), that can be supplied by the
drivers in addition to their "standard" runtime PM callbacks. This
will allow the drivers to be designed to work with generic PM domains
as well as without them.
For backwards compatibility, introduce default .save_state() and
.restore_state() callback routines for PM domains that will execute
a device driver's .runtime_suspend() and .runtime_resume() callbacks,
respectively, for the given device if the driver doesn't provide its
own implementations of .save_state() and .restore_state().
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 94afaa2..3c9451b 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -56,6 +56,16 @@
return GENPD_DEV_CALLBACK(genpd, int, start, dev);
}
+static int genpd_save_dev(struct generic_pm_domain *genpd, struct device *dev)
+{
+ return GENPD_DEV_CALLBACK(genpd, int, save_state, dev);
+}
+
+static int genpd_restore_dev(struct generic_pm_domain *genpd, struct device *dev)
+{
+ return GENPD_DEV_CALLBACK(genpd, int, restore_state, dev);
+}
+
static bool genpd_sd_counter_dec(struct generic_pm_domain *genpd)
{
bool ret = false;
@@ -217,7 +227,6 @@
{
struct generic_pm_domain_data *gpd_data = to_gpd_data(pdd);
struct device *dev = pdd->dev;
- struct device_driver *drv = dev->driver;
int ret = 0;
if (gpd_data->need_restore)
@@ -225,11 +234,9 @@
mutex_unlock(&genpd->lock);
- if (drv && drv->pm && drv->pm->runtime_suspend) {
- genpd_start_dev(genpd, dev);
- ret = drv->pm->runtime_suspend(dev);
- genpd_stop_dev(genpd, dev);
- }
+ genpd_start_dev(genpd, dev);
+ ret = genpd_save_dev(genpd, dev);
+ genpd_stop_dev(genpd, dev);
mutex_lock(&genpd->lock);
@@ -250,18 +257,15 @@
{
struct generic_pm_domain_data *gpd_data = to_gpd_data(pdd);
struct device *dev = pdd->dev;
- struct device_driver *drv = dev->driver;
if (!gpd_data->need_restore)
return;
mutex_unlock(&genpd->lock);
- if (drv && drv->pm && drv->pm->runtime_resume) {
- genpd_start_dev(genpd, dev);
- drv->pm->runtime_resume(dev);
- genpd_stop_dev(genpd, dev);
- }
+ genpd_start_dev(genpd, dev);
+ genpd_restore_dev(genpd, dev);
+ genpd_stop_dev(genpd, dev);
mutex_lock(&genpd->lock);
@@ -1358,6 +1362,44 @@
EXPORT_SYMBOL_GPL(pm_genpd_remove_callbacks);
/**
+ * pm_genpd_default_save_state - Default "save device state" for PM domians.
+ * @dev: Device to handle.
+ */
+static int pm_genpd_default_save_state(struct device *dev)
+{
+ int (*cb)(struct device *__dev);
+ struct device_driver *drv = dev->driver;
+
+ cb = dev_gpd_data(dev)->ops.save_state;
+ if (cb)
+ return cb(dev);
+
+ if (drv && drv->pm && drv->pm->runtime_suspend)
+ return drv->pm->runtime_suspend(dev);
+
+ return 0;
+}
+
+/**
+ * pm_genpd_default_restore_state - Default PM domians "restore device state".
+ * @dev: Device to handle.
+ */
+static int pm_genpd_default_restore_state(struct device *dev)
+{
+ int (*cb)(struct device *__dev);
+ struct device_driver *drv = dev->driver;
+
+ cb = dev_gpd_data(dev)->ops.restore_state;
+ if (cb)
+ return cb(dev);
+
+ if (drv && drv->pm && drv->pm->runtime_resume)
+ return drv->pm->runtime_resume(dev);
+
+ return 0;
+}
+
+/**
* pm_genpd_init - Initialize a generic I/O PM domain object.
* @genpd: PM domain object to initialize.
* @gov: PM domain governor to associate with the domain (may be NULL).
@@ -1400,6 +1442,8 @@
genpd->domain.ops.restore_noirq = pm_genpd_restore_noirq;
genpd->domain.ops.restore = pm_genpd_restore;
genpd->domain.ops.complete = pm_genpd_complete;
+ genpd->dev_ops.save_state = pm_genpd_default_save_state;
+ genpd->dev_ops.restore_state = pm_genpd_default_restore_state;
mutex_lock(&gpd_list_lock);
list_add(&genpd->gpd_list_node, &gpd_list);
mutex_unlock(&gpd_list_lock);
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 8949d2d..731080d 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -26,6 +26,8 @@
struct gpd_dev_ops {
int (*start)(struct device *dev);
int (*stop)(struct device *dev);
+ int (*save_state)(struct device *dev);
+ int (*restore_state)(struct device *dev);
bool (*active_wakeup)(struct device *dev);
};