sh: disabled cache handling fix.

Add code to handle the cache disabled case. Fixes breakage introduced by
37443ef3f0406e855e169c87ae3f4ffb4b6ff635 ("sh: Migrate SH-4 cacheflush
ops to function pointers."). 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>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

diff --git a/arch/sh/mm/cache.c b/arch/sh/mm/cache.c
index 5e1091b..a2dc7f9 100644 (file)
--- a/arch/sh/mm/cache.c
+++ b/arch/sh/mm/cache.c
@@ -265,6 +265,8 @@ static void __init emit_cache_params(void)
 
 void __init cpu_cache_init(void)
 {
+       unsigned int cache_disabled = !(__raw_readl(CCR) & CCR_CACHE_ENABLE);
+
        compute_alias(&boot_cpu_data.icache);
        compute_alias(&boot_cpu_data.dcache);
        compute_alias(&boot_cpu_data.scache);
@@ -273,6 +275,13 @@ void __init cpu_cache_init(void)
        __flush_purge_region            = noop__flush_region;
        __flush_invalidate_region       = noop__flush_region;
 
+       /*
+        * No flushing is necessary in the disabled cache case so we can
+        * just keep the noop functions in local_flush_..() and __flush_..()
+        */
+       if (unlikely(cache_disabled))
+               goto skip;
+
        if (boot_cpu_data.family == CPU_FAMILY_SH2) {
                extern void __weak sh2_cache_init(void);
 
@@ -312,5 +321,6 @@ void __init cpu_cache_init(void)
                sh5_cache_init();
        }
 
+skip:
        emit_cache_params();
 }