[U-Boot] [PATCH v3 1/4] arm: do not force d-cache enable on all boards

[Simon Guinot <simon@sequanux.org>]

Hi Aneesh,

On Thu, Aug 11, 2011 at 08:05:42PM +0530, Aneesh V wrote:
> c2dd0d45540397704de9b13287417d21049d34c6 added dcache_enable()
> to board_init_r(). This enables d-cache for all ARM boards.
> As a result some of the arm boards that are not cache-ready
> are broken. Revert this change and allow platform code to
> take the decision on d-cache enabling.
> 
> Also add some documentation for cache usage in ARM.
> 
> Signed-off-by: Aneesh V <aneesh@ti.com>
> ---
> V2:
>  Updated with additional guidelines in the README.
> ---
>  arch/arm/lib/board.c  |    8 ++----
>  arch/arm/lib/cache.c  |   12 +++++++++++
>  doc/README.arm-caches |   51 +++++++++++++++++++++++++++++++++++++++++++++++++
>  include/common.h      |    1 +
>  4 files changed, 67 insertions(+), 5 deletions(-)
>  create mode 100644 doc/README.arm-caches
> 
> diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
> index 14a56f6..38a31d8 100644
> --- a/arch/arm/lib/board.c
> +++ b/arch/arm/lib/board.c
> @@ -451,11 +451,9 @@ void board_init_r(gd_t *id, ulong dest_addr)
>  	gd->flags |= GD_FLG_RELOC;	/* tell others: relocation done */
>  
>  	monitor_flash_len = _end_ofs;
> -	/*
> -	 * Enable D$:
> -	 * I$, if needed, must be already enabled in start.S
> -	 */
> -	dcache_enable();
> +
> +	/* Enable caches */
> +	enable_caches();
>  
>  	debug("monitor flash len: %08lX\n", monitor_flash_len);
>  	board_init();	/* Setup chipselects */
> diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c
> index 92b61a2..b545fb7 100644
> --- a/arch/arm/lib/cache.c
> +++ b/arch/arm/lib/cache.c
> @@ -53,3 +53,15 @@ void	__flush_dcache_all(void)
>  }
>  void	flush_dcache_all(void)
>  	__attribute__((weak, alias("__flush_dcache_all")));
> +
> +
> +/*
> + * Default implementation of enable_caches()
> + * Real implementation should be in platform code
> + */
> +void __enable_caches(void)
> +{
> +	puts("WARNING: Caches not enabled\n");
> +}
> +void enable_caches(void)
> +	__attribute__((weak, alias("__enable_caches")));
> diff --git a/doc/README.arm-caches b/doc/README.arm-caches
> new file mode 100644
> index 0000000..a833eee
> --- /dev/null
> +++ b/doc/README.arm-caches
> @@ -0,0 +1,51 @@
> +Disabling I-cache:
> +- Set CONFIG_SYS_ICACHE_OFF
> +
> +Disabling D-cache:
> +- Set CONFIG_SYS_DCACHE_OFF
> +
> +Enabling I-cache:
> +- Make sure CONFIG_SYS_ICACHE_OFF is not set and call icache_enable().
> +
> +Enabling D-cache:
> +- Make sure CONFIG_SYS_ICACHE_OFF is not set and call dcache_enable().
               ^
Maybe you will prefer to check for CONFIG_SYS_DCACHE_OFF ?

Regards,

Simon
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