[U-Boot-Users] [PATCH] use CFI-Flash and board depended driver together

Tolunay Orkun listmember at orkun.us
Wed Dec 6 17:57:10 CET 2006

Matvejchikov Ilya wrote:
> Hi all,
> While I try to examine cfi_flash.c file I have found that
> flash_detect_cfi() function used uninitialized value of
> info->cmd_reset:
> flash_get_size()
> {
>    ....
>    if (flash_detect_cfi(info)) {
>        ....
>        switch (info->vendor) {
>            ....
>            info->cmd_reset = x_CMD_RESET;
>            ....
>        }
>    }
> }
> flash_detect_cfi(info)
> {
>    ....
>        flash_write_cmd (info, 0, 0, info->cmd_reset);
>    ....
> }
> Am I right? Or may be - 'Is it true?' :)

Good obvervation... It is true but mostly harmless (if the garbage in 
cmd_reset does not happen to be a valid command). The reset command is 
issued if the attempt to put flash in CFI mode has failed. The line 
could be removed and it would still work. When I designed my last patch 
flash_read_jedec_ids(), I've specifically avoided the info->cmd_reset 
for this reason.

Actually, AMD_CMD_RESET should be applicable to most Intel parts as well 
per CFI spec documents. I think the Linux MTD driver choose to send the 
Intel sequence followed by AMD sequence back to back during the probe.

BTW, Were you able to read my proposals to extend the CFI flash driver 
to handle non-cfi chips. I've only received one comment so far. I am 
waiting to get more comments before I go ahead with coding effort....

Best regards,

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