PM / Runtime: Allow helpers to be called by early platform drivers

Runtime PM helper functions, like pm_runtime_get_sync(), cannot be
called by early platform device drivers, because the devices' power
management locks are not initialized at that time.  This is quite
inconvenient, so modify early_platform_add_devices() to initialize
the devices power management locks as appropriate and make sure that
they won't be initialized more than once if an early platform
device is going to be used as a regular one later.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

3 files changed, 19 insertions, 2 deletions

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index a1a722502587..d51514b79efe 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -22,6 +22,7 @@
 #include <linux/pm_runtime.h>
 
 #include "base.h"
+#include "power/power.h"
 
 #define to_platform_driver(drv) (container_of((drv), struct platform_driver, \
                                  driver))
@@ -948,6 +949,7 @@ void __init early_platform_add_devices(struct platform_device **devs, int num)
                 dev = &devs[i]->dev;
 
                 if (!dev->devres_head.next) {
+                        pm_runtime_early_init(dev);
                         INIT_LIST_HEAD(&dev->devres_head);
                         list_add_tail(&dev->devres_head,
                                       &early_platform_device_list);
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index 8a0dcc7f98f9..0dbfdf4419af 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -2,17 +2,31 @@
 
 static inline void device_pm_init_common(struct device *dev)
 {
-        spin_lock_init(&dev->power.lock);
-        dev->power.power_state = PMSG_INVALID;
+        if (!dev->power.early_init) {
+                spin_lock_init(&dev->power.lock);
+                dev->power.power_state = PMSG_INVALID;
+                dev->power.early_init = true;
+        }
 }
 
 #ifdef CONFIG_PM_RUNTIME
 
+static inline void pm_runtime_early_init(struct device *dev)
+{
+        dev->power.disable_depth = 1;
+        device_pm_init_common(dev);
+}
+
 extern void pm_runtime_init(struct device *dev);
 extern void pm_runtime_remove(struct device *dev);
 
 #else /* !CONFIG_PM_RUNTIME */
 
+static inline void pm_runtime_early_init(struct device *dev)
+{
+        device_pm_init_common(dev);
+}
+
 static inline void pm_runtime_init(struct device *dev) {}
 static inline void pm_runtime_remove(struct device *dev) {}
 
diff --git a/include/linux/pm.h b/include/linux/pm.h
index f067e60a3832..716517af1543 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -510,6 +510,7 @@ struct dev_pm_info {
         bool                    is_prepared:1;  /* Owned by the PM core */
         bool                    is_suspended:1; /* Ditto */
         bool                    ignore_children:1;
+        bool                    early_init:1;   /* Owned by the PM core */
         spinlock_t              lock;
 #ifdef CONFIG_PM_SLEEP
         struct list_head        entry;