[U-Boot] [PATCH 4/8] arm: minor fixes for cache and mmu handling

Albert ARIBAUD
2011-01-08T07:04:47Z

Hi Aneesh,

Le 22/12/2010 12:54, Aneesh V a ?crit :
> 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>
> ---
> arch/arm/lib/cache-cp15.c | 9 +++++++--
> arch/arm/lib/cache.c | 13 ++++++++++++-
> 2 files changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/lib/cache-cp15.c b/arch/arm/lib/cache-cp15.c
> index ca526fb..20aa993 100644
> --- a/arch/arm/lib/cache-cp15.c
> +++ b/arch/arm/lib/cache-cp15.c
> @@ -94,13 +94,18 @@ 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();

Do you know why double MMU setups happen? Can we not fix the execution
path and remove the second MMU setup call there, rather that catching t
on the fly to ignore it?

> @@ -119,7 +124,7 @@ 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 275b6e1..363609a 100644
> --- a/arch/arm/lib/cache.c
> +++ b/arch/arm/lib/cache.c
> @@ -25,7 +25,7 @@
>
> #include<common.h>
>
> -void __flush_cache(unsigned long dummy1, unsigned long dummy2)
> +void __flush_cache(unsigned long start, unsigned long size)
> {
> #if defined(CONFIG_OMAP2420) || defined(CONFIG_ARM1136)
> void arm1136_cache_flush(void);
> @@ -42,3 +42,14 @@ void __flush_cache(unsigned long dummy1, unsigned long dummy2)
> }
> void flush_cache(unsigned long dummy1, unsigned long dummy2)

Please fix also parameters in this declaration.

> __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")));

Amicalement,
--
Albert.