[PATCH v7 04/11] arm: Support restart through restart handler call chain

[Guenter Roeck]

The kernel core now supports a restart handler call chain for system
restart functions.

With this change, the arm_pm_restart callback is now optional, so
drop its initialization and check if it is set before calling it.
Only call the kernel restart handler if arm_pm_restart is not set.

Signed-off-by: Guenter Roeck <linux at roeck-us.net>
Acked-by: Catalin Marinas <catalin.marinas at arm.com>
Acked-by: Heiko Stuebner <heiko at sntech.de>
---
v7: Dropped null_restart and made arm_pm_restart truly optional.
v6: No change.
v5: Renamed restart function to do_kernel_restart
v4: No change.
v3: Use wrapper function to execute notifier call chain.
v2: Only call notifier call chain if arm_pm_restart is not set.
    Do not include linux/watchdog.h.

 arch/arm/kernel/process.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 81ef686..ea279f7 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -114,17 +114,13 @@ void soft_restart(unsigned long addr)
 	BUG();
 }
 
-static void null_restart(enum reboot_mode reboot_mode, const char *cmd)
-{
-}
-
 /*
  * Function pointers to optional machine specific functions
  */
 void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
-void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd) = null_restart;
+void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
 EXPORT_SYMBOL_GPL(arm_pm_restart);
 
 /*
@@ -230,7 +226,10 @@ void machine_restart(char *cmd)
 	local_irq_disable();
 	smp_send_stop();
 
-	arm_pm_restart(reboot_mode, cmd);
+	if (arm_pm_restart)
+		arm_pm_restart(reboot_mode, cmd);
+	else
+		do_kernel_restart(cmd);
 
 	/* Give a grace period for failure to restart of 1s */
 	mdelay(1000);
-- 
1.9.1