[U-Boot] [PATCH 3/6] Davinci: ea20: Add NAND support

Stefano Babic
2011-04-12T07:29:46Z

On 04/11/2011 03:05 PM, Ben Gardiner wrote:

Hi Ben,

>
>> [...]
>> @@ -143,20 +144,20 @@ int board_init(void)
>> irq_init();
>> #endif
>>
>> -#ifdef CONFIG_NAND_DAVINCI
>> /*
>> * NAND CS setup - cycle counts based on da850evm NAND timings in the
>> * Linux kernel @ 25MHz EMIFA
>> */
>> +#ifdef CONFIG_NAND_DAVINCI
>> writel((DAVINCI_ABCR_WSETUP(0) |
>> - DAVINCI_ABCR_WSTROBE(0) |
>> + DAVINCI_ABCR_WSTROBE(1) |
>
> If WSTROBE is modified then the timings are no longer solely based on
> the NAND timings in arch/arm/mach-davinci/board-da850-evm.c in the
> Linux kernel. Can you add an amendment to the comment describing the
> motivation for the extra WSTROBE cycle?

Really this board will not use at all the board-da850-evm.c, but (no
patches are yet pushed) it will have its own board configuration file
(something like arch/arm/mach-davinci/ea20.c). I understand that if no
timing structure is set into the davinci_nand_pdata in Linux, values set
by the bootloader are not overwritten (this is the case for this board
at the moment). Regarding setting the WSTROBE, I understood from manual
(EMIFA) that WSTROBE and RSTROBE cannot be set to zero if the EMA_WAIT
pin is used, as on this board.

Best regards,
Stefano

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