ARM: exynos4: add L2 early resume code

This patch adds code to save L2 register configuration at boot, and to
resume L2 before MMU is enabled in suspend and cpuidle resume paths.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@linaro.org>

2 files changed, 54 insertions, 8 deletions

diff --git a/arch/arm/mach-exynos4/cpu.c b/arch/arm/mach-exynos4/cpu.c
index 746d6fc6d39..979fb5d4367 100644
--- a/arch/arm/mach-exynos4/cpu.c
+++ b/arch/arm/mach-exynos4/cpu.c
@@ -11,6 +11,7 @@
 #include <linux/sched.h>
 #include <linux/sysdev.h>
 
+#include <asm/cacheflush.h>
 #include <asm/mach/map.h>
 #include <asm/mach/irq.h>
 
@@ -31,6 +32,7 @@
 
 #include <mach/regs-irq.h>
 #include <mach/regs-pmu.h>
+#include <mach/pmu.h>
 
 extern int combiner_init(unsigned int combiner_nr, void __iomem *base,
 			 unsigned int irq_start);
@@ -221,16 +223,34 @@ core_initcall(exynos4_core_init);
 #ifdef CONFIG_CACHE_L2X0
 static int __init exynos4_l2x0_cache_init(void)
 {
-	/* TAG, Data Latency Control: 2cycle */
-	__raw_writel(0x110, S5P_VA_L2CC + L2X0_TAG_LATENCY_CTRL);
-	__raw_writel(0x110, S5P_VA_L2CC + L2X0_DATA_LATENCY_CTRL);
+	if (!(__raw_readl(S5P_VA_L2CC + L2X0_CTRL) & 0x1)) {
 
-	/* L2X0 Prefetch Control */
-	__raw_writel(0x30000007, S5P_VA_L2CC + L2X0_PREFETCH_CTRL);
+		l2x0_saved_regs.phy_base = EXYNOS4_PA_L2CC;
+		/* TAG, Data Latency Control: 2 cycles */
+		l2x0_saved_regs.tag_latency = 0x110;
+		l2x0_saved_regs.data_latency = 0x110;
+		l2x0_saved_regs.prefetch_ctrl = 0x30000007;
+		l2x0_saved_regs.pwr_ctrl =
+			(L2X0_DYNAMIC_CLK_GATING_EN | L2X0_STNDBY_MODE_EN);
 
-	/* L2X0 Power Control */
-	__raw_writel(L2X0_DYNAMIC_CLK_GATING_EN | L2X0_STNDBY_MODE_EN,
-		     S5P_VA_L2CC + L2X0_POWER_CTRL);
+		l2x0_regs_phys = virt_to_phys(&l2x0_saved_regs);
+
+		__raw_writel(l2x0_saved_regs.tag_latency,
+				S5P_VA_L2CC + L2X0_TAG_LATENCY_CTRL);
+		__raw_writel(l2x0_saved_regs.data_latency,
+				S5P_VA_L2CC + L2X0_DATA_LATENCY_CTRL);
+
+		/* L2X0 Prefetch Control */
+		__raw_writel(l2x0_saved_regs.prefetch_ctrl,
+				S5P_VA_L2CC + L2X0_PREFETCH_CTRL);
+
+		/* L2X0 Power Control */
+		__raw_writel(l2x0_saved_regs.pwr_ctrl,
+				S5P_VA_L2CC + L2X0_POWER_CTRL);
+
+		clean_dcache_area(&l2x0_regs_phys, sizeof(unsigned long));
+		clean_dcache_area(&l2x0_saved_regs, sizeof(struct l2x0_regs));
+	}
 
 	l2x0_init(S5P_VA_L2CC, 0x7C470001, 0xC200ffff);
 
diff --git a/arch/arm/mach-exynos4/sleep.S b/arch/arm/mach-exynos4/sleep.S
index c19527bf301..3284213a1a3 100644
--- a/arch/arm/mach-exynos4/sleep.S
+++ b/arch/arm/mach-exynos4/sleep.S
@@ -27,6 +27,8 @@
 */
 
 #include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/hardware/cache-l2x0.h>
 
 	.text
 
@@ -47,7 +49,31 @@
 	 * other way of restoring the stack pointer after sleep, and we
 	 * must not write to the code segment (code is read-only)
 	 */
+	.align
+	.data
 
 ENTRY(s3c_cpu_resume)
+	adr	r0, l2x0_regs_phys
+	ldr	r0, [r0]
+	ldr	r1, [r0, #L2X0_R_PHY_BASE]
+	ldr	r2, [r1, #L2X0_CTRL]
+	tst	r2, #0x1
+	bne	resume_l2on
+	ldr	r2, [r0, #L2X0_R_AUX_CTRL]
+	str	r2, [r1, #L2X0_AUX_CTRL]
+	ldr	r2, [r0, #L2X0_R_TAG_LATENCY]
+	str	r2, [r1, #L2X0_TAG_LATENCY_CTRL]
+	ldr	r2, [r0, #L2X0_R_DATA_LATENCY]
+	str	r2, [r1, #L2X0_DATA_LATENCY_CTRL]
+	ldr	r2, [r0, #L2X0_R_PREFETCH_CTRL]
+	str	r2, [r1, #L2X0_PREFETCH_CTRL]
+	ldr	r2, [r0, #L2X0_R_PWR_CTRL]
+	str	r2, [r1, #L2X0_POWER_CTRL]
+	mov	r2, #1
+	str	r2, [r1, #L2X0_CTRL]
+resume_l2on:
 	b	cpu_resume
 ENDPROC(s3c_cpu_resume)
+	.globl l2x0_regs_phys
+l2x0_regs_phys:
+	.long	0