[U-Boot] [PATCH] Fix CFI flash driver for 8-bit bus support

[Stefan Roese <sr@denx.de>]

Hi Aaron,

On Saturday 02 April 2011 09:17:01 Aaron Williams wrote:
> This patch corrects the addresses used when working with Spansion/AMD FLASH
> chips. Addressing for 8 and 16 bits is almost identical except in the
> 16-bit case the LSB of the address is always 0.  The confusion arose
> because the addresses in the datasheet for 16-bit mode are word addresses
> but this code assumed it was byte addresses.
> 
> I have only been able to test this on our Octeon boards which use either an
> 8-bit or 16-bit bus.  I have not tested the case where there's an 8-bit
> part on a 16-bit bus.
> 
> This patch also adds some delays as suggested by Spansion.
> 
> If a part can be both 8 and 16-bits, it forces it to work in 8-bit mode if
> an 8-bit bus is detected.

Thanks.

Apart from the comments from Albert and Rogan, here some further notes:

- Please explain why the delay() calls are added. If really needed, please
  move them into a separate patch, as this seems unrelated to the 8/16
  bit issue.

- Please add a short description and rationale to the commit text (and
  perhaps to cfi_flash.h), why the offsets for the CFI data are now
  changed (e.g. 0x10 -> 0x20).

And one further comment below:
 
> @@ -1043,6 +1049,8 @@ int flash_erase (flash_info_t * info, int s_first,
> int s_last) int prot;
>  	flash_sect_t sect;
>  	int st;
> +
> +	debug("%s: erasing sectors %d to %d\n", __func__, s_first, s_last);
> 
>  	if (info->flash_id != FLASH_MAN_CFI) {
>  		puts ("Can't erase unknown flash type - aborted\n");
> @@ -1082,6 +1090,7 @@ int flash_erase (flash_info_t * info, int s_first,
> int s_last) break;
>  			case CFI_CMDSET_AMD_STANDARD:
>  			case CFI_CMDSET_AMD_EXTENDED:
> +				flash_write_cmd (info, 0, 0, AMD_CMD_RESET);

Is this correct? A reset command in every flash_erase() call?

Thanks.

Cheers,
Stefan

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