[U-Boot] [PATCH v3] arm: cache: always flush cache line size for page table

[Andreas Färber]

Am 07.08.2016 um 19:17 schrieb Stefan Agner:
> From: Stefan Agner <stefan.agner at toradex.com>
> 
> The page table is maintained by the CPU, hence it is safe to always
> align cache flush to a whole cache line size. This allows to use
> mmu_page_table_flush for a single page table, e.g. when configure
> only small regions through mmu_set_region_dcache_behaviour.
> 
> Signed-off-by: Stefan Agner <stefan.agner at toradex.com>
> Tested-by: Fabio Estevam <fabio.estevam at nxp.com>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> ---
> Changes since v2:
> - Fixed spelling misstake
> Changes since v1:
> - Move cache line alignment from mmu_page_table_flush to
>   mmu_set_region_dcache_behaviour
> 
>  arch/arm/lib/cache-cp15.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/lib/cache-cp15.c b/arch/arm/lib/cache-cp15.c
> index 1121dc3..bf79edd 100644
> --- a/arch/arm/lib/cache-cp15.c
> +++ b/arch/arm/lib/cache-cp15.c
> @@ -62,6 +62,7 @@ void mmu_set_region_dcache_behaviour(phys_addr_t start, size_t size,
>  				     enum dcache_option option)
>  {
>  	u32 *page_table = (u32 *)gd->arch.tlb_addr;
> +	phys_addr_t startpt, stoppt;
>  	unsigned long upto, end;
>  
>  	end = ALIGN(start + size, MMU_SECTION_SIZE) >> MMU_SECTION_SHIFT;
> @@ -70,7 +71,17 @@ void mmu_set_region_dcache_behaviour(phys_addr_t start, size_t size,
>  	      option);
>  	for (upto = start; upto < end; upto++)
>  		set_section_dcache(upto, option);
> -	mmu_page_table_flush((u32)&page_table[start], (u32)&page_table[end]);
> +
> +	/*
> +	 * Make sure range is cache line aligned
> +	 * Only CPU maintains page tables, hence it is save to always

"safe"

> +	 * flush complete cache lines...
> +	 */
> +	startpt = (phys_addr_t)&page_table[start];
> +	startpt &= ~(CONFIG_SYS_CACHELINE_SIZE - 1);
> +	stoppt = (phys_addr_t)&page_table[end];
> +	stoppt = ALIGN(stoppt, CONFIG_SYS_CACHELINE_SIZE);
> +	mmu_page_table_flush(startpt, stoppt);
>  }
>  
>  __weak void dram_bank_mmu_setup(int bank)

Regards,
Andreas

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