[ARM] 3802/1: S3C24XX: PM tidy up cache flushing

Change to using flush_cache_all() in pm.c and
also remove the need to flush the cache in the
PM code.

This changes the sleep.S code to have an entry
to store the registers for resume, and then a
second entry (after the caches are cleaned)
to do the suspend and resume.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 34 insertions, 20 deletions

diff --git a/arch/arm/mach-s3c2410/pm.c b/arch/arm/mach-s3c2410/pm.c
index 164a5b5847d7..46dedd37f438 100644
--- a/arch/arm/mach-s3c2410/pm.c
+++ b/arch/arm/mach-s3c2410/pm.c
@@ -35,6 +35,7 @@
 #include <linux/ioport.h>
 #include <linux/delay.h>
 
+#include <asm/cacheflush.h>
 #include <asm/hardware.h>
 #include <asm/io.h>
 
@@ -52,14 +53,6 @@
 
 unsigned long s3c_pm_flags;
 
-/* cache functions from arch/arm/mm/proc-arm920.S */
-
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-extern void arm920_flush_kern_cache_all(void);
-#else
-static void arm920_flush_kern_cache_all(void) { }
-#endif
-
 #define PFX "s3c24xx-pm: "
 
 static struct sleep_save core_save[] = {
@@ -567,7 +560,7 @@ static int s3c2410_pm_enter(suspend_state_t state)
 
         /* flush cache back to ram */
 
-        arm920_flush_kern_cache_all();
+        flush_cache_all();
 
         s3c2410_pm_check_store();
 
@@ -575,7 +568,14 @@ static int s3c2410_pm_enter(suspend_state_t state)
 
         __raw_writel(0x00, S3C2410_CLKCON);  /* turn off clocks over sleep */
 
-        s3c2410_cpu_suspend(regs_save);
+        /* s3c2410_cpu_save will also act as our return point from when
+         * we resume as it saves its own register state, so use the return
+         * code to differentiate return from save and return from sleep */
+
+        if (s3c2410_cpu_save(regs_save) == 0) {
+                flush_cache_all();
+                s3c2410_cpu_suspend();
+        }
 
         /* restore the cpu state */
 
diff --git a/arch/arm/mach-s3c2410/pm.h b/arch/arm/mach-s3c2410/pm.h
index b04e4ca0bb4d..fa8e237cfee8 100644
--- a/arch/arm/mach-s3c2410/pm.h
+++ b/arch/arm/mach-s3c2410/pm.h
@@ -40,7 +40,8 @@ extern unsigned long s3c_pm_flags;
 
 /* from sleep.S */
 
-extern void s3c2410_cpu_suspend(unsigned long *saveblk);
+extern int  s3c2410_cpu_save(unsigned long *saveblk);
+extern void s3c2410_cpu_suspend(void);
 extern void s3c2410_cpu_resume(void);
 
 extern unsigned long s3c2410_sleep_save_phys;
diff --git a/arch/arm/mach-s3c2410/sleep.S b/arch/arm/mach-s3c2410/sleep.S
index a7561a79fc82..e977aa1ffe18 100644
--- a/arch/arm/mach-s3c2410/sleep.S
+++ b/arch/arm/mach-s3c2410/sleep.S
@@ -41,15 +41,25 @@
 
         .text
 
-        /* s3c2410_cpu_suspend
+        /* s3c2410_cpu_save
          *
-         * put the cpu into sleep mode
+         * save enough of the CPU state to allow us to re-start
+         * pm.c code. as we store items like the sp/lr, we will
+         * end up returning from this function when the cpu resumes
+         * so the return value is set to mark this.
+         *
+         * This arangement means we avoid having to flush the cache
+         * from this code.
          *
          * entry:
-         *      r0 = sleep save block
+         *      r0 = pointer to save block
+         *
+         * exit:
+         *      r0 = 0 => we stored everything
+         *           1 => resumed from sleep
         */
 
-ENTRY(s3c2410_cpu_suspend)
+ENTRY(s3c2410_cpu_save)
         stmfd   sp!, { r4 - r12, lr }
 
         @@ store co-processor registers
@@ -62,13 +72,15 @@ ENTRY(s3c2410_cpu_suspend)
 
         stmia   r0, { r4 - r13 }
 
-        @@ flush the caches to ensure everything is back out to
-        @@ SDRAM before the core powers down
+        mov     r0, #0
+        ldmfd   sp, { r4 - r12, pc }
 
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-        bl      arm920_flush_kern_cache_all
-#endif
+        /* s3c2410_cpu_suspend
+         *
+         * put the cpu into sleep mode
+        */
 
+ENTRY(s3c2410_cpu_suspend)
         @@ prepare cpu to sleep
 
         ldr     r4, =S3C2410_REFRESH
@@ -100,6 +112,7 @@ s3c2410_do_sleep:
         @@ turned on, this restores the last bits from the
         @@ stack
 resume_with_mmu:
+        mov     r0, #1
         ldmfd   sp!, { r4 - r12, pc }
 
         .ltorg