ARM: SAMSUNG: Gracefully exit on suspend failure

As per the Exynos5250 User Manual:
When there are pending interrupt events, WFI/WFE instruction are
ignored. To cancel the power-down sequence follow these steps:
1) Disable system power-down using CENTRAL_SEQ_CONFIGURATION register
2) Clear WAKEUP_STAT register
3) Enable interrupt service routine for CPU

Code for early wakeup for exynos already exists. Remove the panic
on suspend failure, clear the wakeup state register and return 1
from cpu_suspend to indicate a failed suspend (to a user daemon).

Older Samsung SoCs have similar panics and I have removed them all.
Haven't touched the S3C2410 sleep code.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/arm/mach-exynos/pm.c b/arch/arm/mach-exynos/pm.c
index b9b539cac81..5106ab83e59 100644
--- a/arch/arm/mach-exynos/pm.c
+++ b/arch/arm/mach-exynos/pm.c
@@ -91,8 +91,8 @@ static int exynos_cpu_suspend(unsigned long arg)
 	/* issue the standby signal into the pm unit. */
 	cpu_do_idle();
 
-	/* we should never get past here */
-	panic("sleep resumed to originator?");
+	pr_info("Failed to suspend the system\n");
+	return 1; /* Aborting suspend */
 }
 
 static void exynos_pm_prepare(void)
@@ -282,6 +282,8 @@ static void exynos_pm_resume(void)
 	if (!(tmp & S5P_CENTRAL_LOWPWR_CFG)) {
 		tmp |= S5P_CENTRAL_LOWPWR_CFG;
 		__raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);
+		/* clear the wakeup state register */
+		__raw_writel(0x0, S5P_WAKEUP_STAT);
 		/* No need to perform below restore code */
 		goto early_wakeup;
 	}