[PATCH] PM: suspend: Do not call suspend_ops->begin()/end() for s2idle

[Ovidiu Panait]

Commit 7602c0ec0bbf ("firmware: psci: Set
pm_set_resume/suspend_via_firmware() for SYSTEM_SUSPEND") made
psci_system_suspend_begin() call pm_set_suspend_via_firmware(), so that
device drivers can prepare for the possible removal of the power before
PSCI SYSTEM_SUSPEND.

Since then, on platforms where PSCI firmware supports SYSTEM_SUSPEND,
pm_suspend_via_firmware() returns true during both s2ram and s2idle.
This is inconsistent, since SYSTEM_SUSPEND is only invoked for s2ram.

This was observed while investigating PCI-related suspend/resume issues
on Renesas platforms (RZ/G3S, RZ/V2H), and was traced to
platform_suspend_begin() falling back to suspend_ops->begin() (PSCI in
this case) when there is no s2idle_ops->begin() callback:

  platform_suspend_begin(PM_SUSPEND_TO_IDLE)
    suspend_ops->begin()
      psci_system_suspend_begin()
        pm_set_suspend_via_firmware()

platform_resume_end() falls back to suspend_ops->end() in the same way.

Since s2idle has its own set of callbacks in s2idle_ops, make
platform_suspend_begin() and platform_resume_end() only invoke those for
s2idle, like the other platform_*() helpers do.

Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@xxxxxxxxxxx>
---
 kernel/power/suspend.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 57c44268698f7..32c055df02da7 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -306,20 +306,24 @@ static void platform_resume_finish(suspend_state_t state)
 
 static int platform_suspend_begin(suspend_state_t state)
 {
-	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
-		return s2idle_ops->begin();
-	else if (suspend_ops && suspend_ops->begin)
+	if (state == PM_SUSPEND_TO_IDLE) {
+		if (s2idle_ops && s2idle_ops->begin)
+			return s2idle_ops->begin();
+	} else if (suspend_ops && suspend_ops->begin) {
 		return suspend_ops->begin(state);
-	else
-		return 0;
+	}
+
+	return 0;
 }
 
 static void platform_resume_end(suspend_state_t state)
 {
-	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
-		s2idle_ops->end();
-	else if (suspend_ops && suspend_ops->end)
+	if (state == PM_SUSPEND_TO_IDLE) {
+		if (s2idle_ops && s2idle_ops->end)
+			s2idle_ops->end();
+	} else if (suspend_ops && suspend_ops->end) {
 		suspend_ops->end();
+	}
 }
 
 static void platform_recover(suspend_state_t state)
-- 
2.34.1