[U-Boot] [PATCH] arm: at91sam9n12: change EBI IO to high drive mode

[Tom Rini]

On Wed, Jul 17, 2013 at 05:14:17PM +0800, Bo Shen wrote:

> As both the DDR SDRAM and NAND flash connect to EBI on at91sam9n12
> and share the lower 8 bits data line. If use low drive of the data
> line, it will cause DDR data access corrupt in lower address, so
> change the data line to high drive mode
> 
> This will fix the Linux kernel boot issue when use Lower address
> 
> Signed-off-by: Bo Shen <voice.shen at atmel.com>
> ---
>  board/atmel/at91sam9n12ek/at91sam9n12ek.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/board/atmel/at91sam9n12ek/at91sam9n12ek.c b/board/atmel/at91sam9n12ek/at91sam9n12ek.c
> index 3013a42..66c4c1f 100644
> --- a/board/atmel/at91sam9n12ek/at91sam9n12ek.c
> +++ b/board/atmel/at91sam9n12ek/at91sam9n12ek.c
> @@ -59,7 +59,7 @@ static void at91sam9n12ek_nand_hw_init(void)
>  	/* Configure databus */
>  	csa &= ~AT91_MATRIX_NFD0_ON_D16; /* nandflash connect to D0~D15 */
>  	/* Configure IO drive */
> -	csa &= ~AT91_MATRIX_EBI_EBI_IOSR_NORMAL;
> +	csa |= AT91_MATRIX_EBI_EBI_IOSR_NORMAL;
>  
>  	writel(csa, &matrix->ebicsa);
>  

So, the change is small and isolated, so I'm OK applying it to master
directly, once we've got acks.  But it sounds like there's a question of
"why does this fix the problem" and "how does the problem even happen?".

-- 
Tom
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