[U-Boot] [PATCH] mtd: cfi: Fix checking status register feature

[Stefan Roese]

On 21.11.2017 10:54, Marek Vasut wrote:
> On 11/21/2017 03:52 AM, York Sun wrote:
>> On 11/18/2017 11:09 AM, York Sun wrote:
>>> Commit 72443c7f7d21 ("mtd: cfi: Add support for status register
>>> polling") added a feature check to determine if status register
>>> is available for certain flash chips. The "lower software bits"
>>> register used to determine this feature is not backward compati-
>>> ble. Older flash chips without this feature has reserved value
>>> 0xff. Instead of checking "lower software bits" register, use
>>> CFI primary vendor-specific extended query. Since CFI version
>>> 1.4, software features can be read from offset 0x53 according to
>>> document AN201168 from Cypress.
>>>
>>> Signed-off-by: York Sun <york.sun at nxp.com>
>>> CC: Marek Vasut <marek.vasut at gmail.com>
>>> ---
>>>
>>>   drivers/mtd/cfi_flash.c | 12 +++++++++---
>>>   1 file changed, 9 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
>>> index 8a5babe..f096e03 100644
>>> --- a/drivers/mtd/cfi_flash.c
>>> +++ b/drivers/mtd/cfi_flash.c
>>> @@ -1694,7 +1694,7 @@ static void cmdset_amd_read_jedec_ids(flash_info_t *info)
>>>   {
>>>   	ushort bankId = 0;
>>>   	uchar  manuId;
>>> -	uchar  lsbits;
>>> +	uchar  feature;
>>>   
>>>   	flash_write_cmd(info, 0, 0, AMD_CMD_RESET);
>>>   	flash_unlock_seq(info, 0);
>>> @@ -1710,8 +1710,14 @@ static void cmdset_amd_read_jedec_ids(flash_info_t *info)
>>>   	}
>>>   	info->manufacturer_id = manuId;
>>>   
>>> -	lsbits = flash_read_uchar(info, FLASH_OFFSET_LOWER_SW_BITS);
>>> -	info->sr_supported = lsbits & BIT(0);
>>> +	debug("info->ext_addr = 0x%x, cfi_version = 0x%x\n",
>>> +	      info->ext_addr, info->cfi_version);
>>> +	if (info->ext_addr && info->cfi_version >= 0x3134) {
>>> +		/* read software feature (at 0x53) */
>>> +		feature = flash_read_uchar(info, info->ext_addr + 0x13);
>>> +		debug("feature = 0x%x\n", feature);
>>> +		info->sr_supported = feature & 0x1;
>>> +	}
>>>   
>>>   	switch (info->chipwidth){
>>>   	case FLASH_CFI_8BIT:
>>>
>>
>> Mark,
>>
>> Can you test this patch on your platforms? I verified on my boards.
> 
> Yes, I am getting to it ... will do this week.

Marek, did you find some time to test this patch on your platform?

Thanks,
Stefan