* [PATCH] sh: disabled cache handling fix for sh4
@ 2009-10-16 1:20 Magnus Damm
2009-10-16 5:39 ` Paul Mundt
0 siblings, 1 reply; 2+ messages in thread
From: Magnus Damm @ 2009-10-16 1:20 UTC (permalink / raw)
To: linux-sh
From: Magnus Damm <damm@opensource.se>
Add code to handle the cache disabled case for sh4. Fixes breakage
introduced by 37443ef3f0406e855e169c87ae3f4ffb4b6ff635. Without
this patch configuring caches off with CONFIG_CACHE_OFF=y makes
kfr2r09 and migo-r lock up in fbdev deferred io or early user space.
Signed-off-by: Magnus Damm <damm@opensource.se>
---
2.6.32 material
arch/sh/mm/cache-sh4.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/sh/mm/cache-sh4.c b/arch/sh/mm/cache-sh4.c
index a98c7d8..c1615d8 100644
--- a/arch/sh/mm/cache-sh4.c
+++ b/arch/sh/mm/cache-sh4.c
@@ -709,6 +709,7 @@ extern void __weak sh4__flush_region_init(void);
*/
void __init sh4_cache_init(void)
{
+ unsigned int cache_enabled = !!(__raw_readl(CCR) & CCR_CACHE_ENABLE);
unsigned int wt_enabled = !!(__raw_readl(CCR) & CCR_CACHE_WT);
printk("PVR=%08x CVR=%08x PRR=%08x\n",
@@ -716,6 +717,17 @@ void __init sh4_cache_init(void)
ctrl_inl(CCN_CVR),
ctrl_inl(CCN_PRR));
+ /* disabled cache handling:
+ *
+ * __flush_dcache_segment_fn() implementations in this file make use
+ * of the movca instruction which bombs out if caches are disabled.
+ *
+ * no flushing is necessary in the disabled cache case so we can
+ * just keep the noop functions in local_flush_..() and __flush_..()
+ */
+ if (!cache_enabled)
+ return;
+
if (wt_enabled)
__flush_dcache_segment_fn = __flush_dcache_segment_writethrough;
else {
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] sh: disabled cache handling fix for sh4
2009-10-16 1:20 [PATCH] sh: disabled cache handling fix for sh4 Magnus Damm
@ 2009-10-16 5:39 ` Paul Mundt
0 siblings, 0 replies; 2+ messages in thread
From: Paul Mundt @ 2009-10-16 5:39 UTC (permalink / raw)
To: linux-sh
On Fri, Oct 16, 2009 at 10:20:06AM +0900, Magnus Damm wrote:
> From: Magnus Damm <damm@opensource.se>
>
> Add code to handle the cache disabled case for sh4. Fixes breakage
> introduced by 37443ef3f0406e855e169c87ae3f4ffb4b6ff635. Without
> this patch configuring caches off with CONFIG_CACHE_OFF=y makes
> kfr2r09 and migo-r lock up in fbdev deferred io or early user space.
>
> Signed-off-by: Magnus Damm <damm@opensource.se>
Applied after moving it to cache.c and some tidying.
^ permalink raw reply [flat|nested] 2+ messages in thread
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