AT91: pm: make sure that r0 is 0 when dealing with cache operations
Nicolas Ferre [Fri, 22 Oct 2010 16:55:39 +0000 (18:55 +0200)]
When using CP15 cache operations (c7), we make sure that Rd (r0)
is actually 0 as ARM 926 TRM is saying.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/mach-at91/pm.c
arch/arm/mach-at91/pm.h
arch/arm/mach-at91/pm_slowclock.S

index 87a31ba..dafbacc 100644 (file)
@@ -261,8 +261,13 @@ static int at91_pm_enter(suspend_state_t state)
                         * For ARM 926 based chips, this requirement is weaker
                         * as at91sam9 can access a RAM in self-refresh mode.
                         */
-                       asm("b 1f; .align 5; 1:");
-                       asm("mcr p15, 0, r0, c7, c10, 4");      /* drain write buffer */
+                       asm volatile (  "mov r0, #0\n\t"
+                                       "b 1f\n\t"
+                                       ".align 5\n\t"
+                                       "1: mcr p15, 0, r0, c7, c10, 4\n\t"
+                                       : /* no output */
+                                       : /* no input */
+                                       : "r0");
                        saved_lpr = sdram_selfrefresh_enable();
                        wait_for_interrupt_enable();
                        sdram_selfrefresh_disable(saved_lpr);
index 2c4424b..ce9a206 100644 (file)
@@ -21,7 +21,8 @@ static inline u32 sdram_selfrefresh_enable(void)
 }
 
 #define sdram_selfrefresh_disable(saved_lpr)   at91_sys_write(AT91_SDRAMC_LPR, saved_lpr)
-#define wait_for_interrupt_enable()            asm("mcr p15, 0, r0, c7, c0, 4")
+#define wait_for_interrupt_enable()            asm volatile ("mcr p15, 0, %0, c7, c0, 4" \
+                                                               : : "r" (0))
 
 #elif defined(CONFIG_ARCH_AT91CAP9)
 #include <mach/at91cap9_ddrsdr.h>
index b6b00a1..f7922a4 100644 (file)
@@ -124,6 +124,7 @@ ENTRY(at91_slow_clock)
        ldr     r5, .at91_va_base_ramc1
 
        /* Drain write buffer */
+       mov     r0, #0
        mcr     p15, 0, r0, c7, c10, 4
 
 #ifdef CONFIG_ARCH_AT91RM9200