ARM: S5P: add L2 early resume code

This patch adds code to resume L2 before MMU is enabled in
suspend and cpuidle resume paths. s3c_cpu_resume is moved to the
data section with appropriate comments.

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

1 files changed, 38 insertions, 6 deletions

diff --git a/arch/arm/plat-s5p/sleep.S b/arch/arm/plat-s5p/sleep.S
index 0fd591bfc9fd..006bd01eda02 100644
--- a/arch/arm/plat-s5p/sleep.S
+++ b/arch/arm/plat-s5p/sleep.S
@@ -23,9 +23,18 @@
 */
 
 #include <linux/linkage.h>
-#include <asm/assembler.h>
+#include <asm/asm-offsets.h>
+#include <asm/hardware/cache-l2x0.h>
 
-        .text
+/*
+ *       The following code is located into the .data section. This is to
+ *       allow l2x0_regs_phys to be accessed with a relative load while we
+ *       can't rely on any MMU translation. We could have put l2x0_regs_phys
+ *       in the .text section as well, but some setups might insist on it to
+ *       be truly read-only. (Reference from: arch/arm/kernel/sleep.S)
+ */
+        .data
+        .align
 
         /*
          * sleep magic, to allow the bootloader to check for an valid
@@ -39,11 +48,34 @@
          * s3c_cpu_resume
          *
          * resume code entry for bootloader to call
-         *
-         * we must put this code here in the data segment as we have no
-         * other way of restoring the stack pointer after sleep, and we
-         * must not write to the code segment (code is read-only)
          */
 
 ENTRY(s3c_cpu_resume)
+#ifdef CONFIG_CACHE_L2X0
+        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:
+#endif
         b       cpu_resume
+ENDPROC(s3c_cpu_resume)
+#ifdef CONFIG_CACHE_L2X0
+        .globl l2x0_regs_phys
+l2x0_regs_phys:
+        .long   0
+#endif