arm: minor fixes for cache and mmu handling

1. make sure that page table setup is not done multiple times
2. flush_dcache_all() is more appropriate while disabling cache
   than a range flush on the entire memory(flush_cache())

   Provide a default implementation for flush_dcache_all()
   for backward compatibility and to avoid build issues.

Signed-off-by: Aneesh V <aneesh@ti.com>

diff --git a/arch/arm/lib/cache-cp15.c b/arch/arm/lib/cache-cp15.c
index 51831a96b54c5562e36f9e14c740d38e452cd345..e6c3eae6f9d2dad1b0bfe2f73d58922439870afa 100644 (file)
--- a/arch/arm/lib/cache-cp15.c
+++ b/arch/arm/lib/cache-cp15.c
@@ -92,13 +92,18 @@ static inline void mmu_setup(void)
        set_cr(reg | CR_M);
 }
 
+static int mmu_enabled(void)
+{
+       return get_cr() & CR_M;
+}
+
 /* cache_bit must be either CR_I or CR_C */
 static void cache_enable(uint32_t cache_bit)
 {
        uint32_t reg;
 
        /* The data cache is not active unless the mmu is enabled too */
-       if (cache_bit == CR_C)
+       if ((cache_bit == CR_C) && !mmu_enabled())
                mmu_setup();
        reg = get_cr(); /* get control reg. */
        cp_delay();
@@ -117,7 +122,7 @@ static void cache_disable(uint32_t cache_bit)
                        return;
                /* if disabling data cache, disable mmu too */
                cache_bit |= CR_M;
-               flush_cache(0, ~0);
+               flush_dcache_all();
        }
        reg = get_cr();
        cp_delay();

diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c
index dc3242c90d8d17d7529e277dd0552f76971dcc5d..92b61a26531a6d922eb40a2e24e437b6f8b36681 100644 (file)
--- a/arch/arm/lib/cache.c
+++ b/arch/arm/lib/cache.c
@@ -42,3 +42,14 @@ void  __flush_cache(unsigned long start, unsigned long size)
 }
 void  flush_cache(unsigned long start, unsigned long size)
        __attribute__((weak, alias("__flush_cache")));
+
+/*
+ * Default implementation:
+ * do a range flush for the entire range
+ */
+void   __flush_dcache_all(void)
+{
+       flush_cache(0, ~0);
+}
+void   flush_dcache_all(void)
+       __attribute__((weak, alias("__flush_dcache_all")));