lkml.org 
[lkml]   [2010]   [Oct]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 2/2] AT91: pm: make sure that r0 is 0 when dealing with cache operations
Date
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 | 1 +
arch/arm/mach-at91/pm.h | 2 +-
arch/arm/mach-at91/pm_slowclock.S | 1 +
3 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index 87a31ba..1d9f204 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -261,6 +261,7 @@ 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("mov r0, #0"); /* clear r0 for CP15 accesses */
asm("b 1f; .align 5; 1:");
asm("mcr p15, 0, r0, c7, c10, 4"); /* drain write buffer */
saved_lpr = sdram_selfrefresh_enable();
diff --git a/arch/arm/mach-at91/pm.h b/arch/arm/mach-at91/pm.h
index 2c4424b..be081c9 100644
--- a/arch/arm/mach-at91/pm.h
+++ b/arch/arm/mach-at91/pm.h
@@ -21,7 +21,7 @@ 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("mcr p15, 0, r0, c7, c0, 4") /* r0 is 0 here */

#elif defined(CONFIG_ARCH_AT91CAP9)
#include <mach/at91cap9_ddrsdr.h>
diff --git a/arch/arm/mach-at91/pm_slowclock.S b/arch/arm/mach-at91/pm_slowclock.S
index b6b00a1..f7922a4 100644
--- a/arch/arm/mach-at91/pm_slowclock.S
+++ b/arch/arm/mach-at91/pm_slowclock.S
@@ -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
--
1.7.3


\
 
 \ /
  Last update: 2010-10-22 18:25    [W:0.039 / U:2.356 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site