[PATCH] arm: exynos4: Fix suspend/resume hang

[Inderpal Singh]

commit d0341c61a2 removed the l2 cache save/restore from pm.c and commit
7c6035b63b added the l2 cache restoration in sleep.s to early enable the
cache in resume path.

With these changes the system hangs while resuming when vdd_arm
is turned off in suspended state. The cache needs to be invalidated
before turning it on, as it was being done before mentioned commits.

Signed-off-by: Inderpal Singh <inderpal.singh at linaro.org>
---
 arch/arm/mach-exynos/common.h     |    1 +
 arch/arm/mach-exynos/pm.c         |    4 ++++
 arch/arm/plat-samsung/s5p-sleep.S |   23 +++++++++++++++++++++++
 3 files changed, 28 insertions(+)

diff --git a/arch/arm/mach-exynos/common.h b/arch/arm/mach-exynos/common.h
index af33872..056d9ce 100644
--- a/arch/arm/mach-exynos/common.h
+++ b/arch/arm/mach-exynos/common.h
@@ -78,6 +78,7 @@ enum sys_powerdown {
 };
 
 extern unsigned long l2x0_regs_phys;
+extern unsigned long wake_reason_reg_phys;
 struct exynos_pmu_conf {
 	void __iomem *reg;
 	unsigned int val[NUM_SYS_POWERDOWN];
diff --git a/arch/arm/mach-exynos/pm.c b/arch/arm/mach-exynos/pm.c
index f459afd..b10513c 100644
--- a/arch/arm/mach-exynos/pm.c
+++ b/arch/arm/mach-exynos/pm.c
@@ -220,6 +220,10 @@ static __init int exynos_pm_drvinit(void)
 
 	s3c_pm_init();
 
+#ifdef CONFIG_CACHE_L2X0
+	if (!soc_is_exynos5250() && !soc_is_exynos5440())
+		wake_reason_reg_phys = virt_to_phys(S5P_INFORM1);
+#endif
 	/* All wakeup disable */
 
 	tmp = __raw_readl(S5P_WAKEUP_MASK);
diff --git a/arch/arm/plat-samsung/s5p-sleep.S b/arch/arm/plat-samsung/s5p-sleep.S
index bdf6dad..74331e2 100644
--- a/arch/arm/plat-samsung/s5p-sleep.S
+++ b/arch/arm/plat-samsung/s5p-sleep.S
@@ -24,6 +24,7 @@
 #include <linux/linkage.h>
 #include <asm/asm-offsets.h>
 #include <asm/hardware/cache-l2x0.h>
+#include <mach/regs-pmu.h>
 
 /*
  *	 The following code is located into the .data section. This is to
@@ -67,6 +68,25 @@ ENTRY(s3c_cpu_resume)
 	str	r2, [r1, #L2X0_PREFETCH_CTRL]
 	ldr	r2, [r0, #L2X0_R_PWR_CTRL]
 	str	r2, [r1, #L2X0_POWER_CTRL]
+
+        /* check resume reason */
+	adr	r0, wake_reason_reg_phys
+	ldr	r0, [r0]
+	ldr	r2, [r0]
+	ldr	r0, =S5P_CHECK_SLEEP
+	cmp	r0, r2
+	bne	turn_cache_on
+
+	/* Invalidate the cache if resume from sleep */
+	ldr	r2, =0xffff
+	str	r2, [r1, #L2X0_INV_WAY]
+wait:
+	ldr	r2, [r1, #L2X0_INV_WAY]
+	ldr	r0, =0xffff
+	ands	r2, r2, r0
+	bne	wait
+
+turn_cache_on:
 	mov	r2, #1
 	str	r2, [r1, #L2X0_CTRL]
 resume_l2on:
@@ -77,4 +97,7 @@ ENDPROC(s3c_cpu_resume)
 	.globl l2x0_regs_phys
 l2x0_regs_phys:
 	.long	0
+	.globl wake_reason_reg_phys
+wake_reason_reg_phys:
+	.long	0
 #endif
-- 
1.7.9.5