PM/Suspend: Introduce two new platform callbacks to avoid breakage

Commit 900af0d973856d6feb6fc088c2d0d3fde57707d3 (PM: Change suspend
code ordering) changed the ordering of suspend code in such a way
that the platform .prepare() callback is now executed after the
device drivers' late suspend callbacks have run.  Unfortunately, this
turns out to break ARM platforms that need to talk via I2C to power
control devices during the .prepare() callback.

For this reason introduce two new platform suspend callbacks,
.prepare_late() and .wake(), that will be called just prior to
disabling non-boot CPUs and right after bringing them back on line,
respectively, and use them instead of .prepare() and .finish() for
ACPI suspend.  Make the PM core execute the .prepare() and .finish()
platform suspend callbacks where they were executed previously (that
is, right after calling the regular suspend methods provided by
device drivers and right before executing their regular resume
methods, respectively).

It is not necessary to make analogous changes to the hibernation
code and data structures at the moment, because they are only used
by ACPI platforms.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Len Brown <len.brown@intel.com>

1 files changed, 17 insertions, 7 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index f172f41858bb..f99ed6a75eac 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -291,20 +291,26 @@ static int suspend_enter(suspend_state_t state)
 
         device_pm_lock();
 
+        if (suspend_ops->prepare) {
+                error = suspend_ops->prepare();
+                if (error)
+                        goto Done;
+        }
+
         error = device_power_down(PMSG_SUSPEND);
         if (error) {
                 printk(KERN_ERR "PM: Some devices failed to power down\n");
-                goto Done;
+                goto Platfrom_finish;
         }
 
-        if (suspend_ops->prepare) {
-                error = suspend_ops->prepare();
+        if (suspend_ops->prepare_late) {
+                error = suspend_ops->prepare_late();
                 if (error)
                         goto Power_up_devices;
         }
 
         if (suspend_test(TEST_PLATFORM))
-                goto Platfrom_finish;
+                goto Platform_wake;
 
         error = disable_nonboot_cpus();
         if (error || suspend_test(TEST_CPUS))
@@ -326,13 +332,17 @@ static int suspend_enter(suspend_state_t state)
  Enable_cpus:
         enable_nonboot_cpus();
 
- Platfrom_finish:
-        if (suspend_ops->finish)
-                suspend_ops->finish();
+ Platform_wake:
+        if (suspend_ops->wake)
+                suspend_ops->wake();
 
  Power_up_devices:
         device_power_up(PMSG_RESUME);
 
+ Platfrom_finish:
+        if (suspend_ops->finish)
+                suspend_ops->finish();
+
  Done:
         device_pm_unlock();