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

[Albert ARIBAUD]

Hi Aneesh,

Le 22/12/2010 12:54, Aneesh V a écrit :
> 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 at 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.