* [U-Boot] [PATCH] FIX for dcache_disable() for ARM926ej-s
@ 2011-10-21 6:44 Bas van den Berg
2011-10-21 12:08 ` Sergei Shtylyov
2011-10-24 21:49 ` Albert ARIBAUD
0 siblings, 2 replies; 3+ messages in thread
From: Bas van den Berg @ 2011-10-21 6:44 UTC (permalink / raw)
To: u-boot
the cache also needs to be invalidated, not just flushed, Since re-enabling it,
can cause inconsistent data without invalidation. See example below.
in c-file:
static int num = 1;
void test() {
num = 1;
dcache_enable();
printf("Cache on, num=%d\n", num);
num = 2;
dcache_disable();
printf("Cache off, num=%d\n", num);
num = 1;
dcache_enable();
printf("Cache on, num=%d\n", num); // -> prints 2 instead of 1!!
dcache_disable();
printf("Cache off, num=%d\n", num);
}
---
arch/arm/lib/cache.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c
index b545fb7..10eb8c9 100644
--- a/arch/arm/lib/cache.c
+++ b/arch/arm/lib/cache.c
@@ -37,6 +37,8 @@ void __flush_cache(unsigned long start, unsigned long size)
asm("0: mrc p15, 0, r15, c7, c10, 3\n\t" "bne 0b\n" : : : "memory");
/* disable write buffer as well (page 2-22) */
asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0));
+ /* Invalidate dcache as well */
+ asm("mcr p15, 0, %0, c7, c6, 0" : : "r" (0));
#endif
return;
}
--
1.7.0.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [U-Boot] [PATCH] FIX for dcache_disable() for ARM926ej-s
2011-10-21 6:44 [U-Boot] [PATCH] FIX for dcache_disable() for ARM926ej-s Bas van den Berg
@ 2011-10-21 12:08 ` Sergei Shtylyov
2011-10-24 21:49 ` Albert ARIBAUD
1 sibling, 0 replies; 3+ messages in thread
From: Sergei Shtylyov @ 2011-10-21 12:08 UTC (permalink / raw)
To: u-boot
Hello.
On 21-10-2011 10:44, Bas van den Berg wrote:
> the cache also needs to be invalidated, not just flushed, Since re-enabling it,
> can cause inconsistent data without invalidation. See example below.
> in c-file:
> static int num = 1;
> void test() {
> num = 1;
> dcache_enable();
> printf("Cache on, num=%d\n", num);
> num = 2;
> dcache_disable();
> printf("Cache off, num=%d\n", num);
> num = 1;
> dcache_enable();
> printf("Cache on, num=%d\n", num); // -> prints 2 instead of 1!!
> dcache_disable();
> printf("Cache off, num=%d\n", num);
> }
> ---
> arch/arm/lib/cache.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
> diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c
> index b545fb7..10eb8c9 100644
> --- a/arch/arm/lib/cache.c
> +++ b/arch/arm/lib/cache.c
> @@ -37,6 +37,8 @@ void __flush_cache(unsigned long start, unsigned long size)
> asm("0: mrc p15, 0, r15, c7, c10, 3\n\t" "bne 0b\n" : : : "memory");
> /* disable write buffer as well (page 2-22) */
> asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0));
> + /* Invalidate dcache as well */
> + asm("mcr p15, 0, %0, c7, c6, 0" : : "r" (0));
Please indent with tabs as above.
WBR, Sergei
^ permalink raw reply [flat|nested] 3+ messages in thread
* [U-Boot] [PATCH] FIX for dcache_disable() for ARM926ej-s
2011-10-21 6:44 [U-Boot] [PATCH] FIX for dcache_disable() for ARM926ej-s Bas van den Berg
2011-10-21 12:08 ` Sergei Shtylyov
@ 2011-10-24 21:49 ` Albert ARIBAUD
1 sibling, 0 replies; 3+ messages in thread
From: Albert ARIBAUD @ 2011-10-24 21:49 UTC (permalink / raw)
To: u-boot
Hi Bas,
Le 21/10/2011 08:44, Bas van den Berg a ?crit :
> the cache also needs to be invalidated, not just flushed, Since re-enabling it,
> can cause inconsistent data without invalidation. See example below.
>
> in c-file:
> static int num = 1;
>
> void test() {
> num = 1;
> dcache_enable();
> printf("Cache on, num=%d\n", num);
> num = 2;
> dcache_disable();
> printf("Cache off, num=%d\n", num);
> num = 1;
> dcache_enable();
> printf("Cache on, num=%d\n", num); // -> prints 2 instead of 1!!
> dcache_disable();
> printf("Cache off, num=%d\n", num);
> }
This part of the patch is what will stay in the GIT tree as the commit
message. Here it is too verbose. Remove useless example.
Amicalement,
--
Albert.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2011-10-21 6:44 [U-Boot] [PATCH] FIX for dcache_disable() for ARM926ej-s Bas van den Berg
2011-10-21 12:08 ` Sergei Shtylyov
2011-10-24 21:49 ` Albert ARIBAUD
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