[PATCH] mtd: spi-nor: spansion: Add SMPT fixup for S25FS512S

[Tudor Ambarus]

On 10/17/25 5:04 PM, Marek Vasut wrote:
> On 10/13/25 5:41 PM, Tudor Ambarus wrote:
> 
> Hello Tudor,

Hi!

> 
>>>> The "Index Value" shall be the map_id that you passed in the code:
>>>> spi_nor_post_smpt_fixups(nor, &map_id);
>>>>
>>>> Can you please print the map_id value that you obtain without updating it?
>>>
>>> 0x4
>>
>> This translates to CR3NV[3] = 1, CR1NV[2] = 0,  CR3NV[1] = 0.
>>>
>>>> Let's also print the values of CR3NV and CR1NV.
>>>
>>> Both 0x0 and 0x0 .
>>
>> But here CR3NV is 0, it contradicts the result from above.
> 
> Maybe I messed up and was reading it the wrong way ?
> 
>> Maybe it's the same problem that Takahiro identified: the flash needs
>> 8 dummy cycles, but the code uses zero dummy cycles, resulting in
>> reading garbage data, depending on whether your IO lines are pulled up/down
>> or floating.
>>
>> Can you redo the test with the following please?
> 
> Sure, although I saw some further discussion between you and Kuwano-san , is this still applicable ?

It's still applicable, it will confirm what Kuwano-san discovered:
the flash needs 8 dummy cycles for using that read reg command.

We'll also need a hook to amend the CR3NV[1] value (which is reserved,
zero on some flavors of flash) and replace it with 1, similar to what
you did in this patch.

You can either test or let Kuwano-san come up with a patch addressing
both issues and test his patch afterwards, sync up with him please.

> 
>> diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
>> index 21727f9a4ac6..85443c903e59 100644
>> --- a/drivers/mtd/spi-nor/sfdp.c
>> +++ b/drivers/mtd/spi-nor/sfdp.c
>> @@ -752,7 +752,7 @@ static const u32 *spi_nor_get_map_in_use(struct spi_nor *nor, const u32 *smpt,
>>                    read_data_mask = SMPT_CMD_READ_DATA(smpt[i]);
>>                  nor->addr_nbytes = spi_nor_smpt_addr_nbytes(nor, smpt[i]);
>> -               nor->read_dummy = spi_nor_smpt_read_dummy(nor, smpt[i]);
>> +               nor->read_dummy = 8;
>>                  nor->read_opcode = SMPT_CMD_OPCODE(smpt[i]);
>>                  addr = smpt[i + 1];
>>   @@ -767,6 +767,8 @@ static const u32 *spi_nor_get_map_in_use(struct spi_nor *nor, const u32 *smpt,
>>                   * Configuration that is currently in use.
>>                   */
>>                  map_id = map_id << 1 | !!(*buf & read_data_mask);
>> +               dev_err(nor->dev, "i = %d, buf = %02x, map_id = %02x\n",
>> +                       i, buf[0], map_id);
>>          }
> Sorry for the late reply.
yeah, no worries, it's still fresh.

Cheers,
ta