Re: [PATCH 1/2] mtd: spi-nor: introduce SNOR_ID3()

[<Tudor.Ambarus@microchip.com>]

On 7/19/22 08:57, Tudor.Ambarus@microchip.com wrote:
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> 
> On 5/10/22 17:02, Michael Walle wrote:
> 
> Hi!
> 
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> Up until now, flashes were defined by specifying the JEDEC ID, the
>> sector size and the number of sectors. This can be read by parsing the
>> SFDP, we don't have to specify it. Thus provide a new macro SNOR_ID3()
>> which just takes the JEDEC ID and implicitly set .parse_sfdp = true. All
>> new flashes which have SFDP should use this macro.
> 
> I like the idea, but you need to refine it a bit.
> Your assumptions are true only for flashes that are compliant with SFDP revB or
> later because params->page_size is initialized by querying BFPT DWORD 11. I think
> it would be good to specify this in the comment section. Also, I think you introduce
> a bug in spi_nor_select_erase() when CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is not
> selected. wanted_size will be zero, will you select an invalid erase type?
> Would you please resubmit?
> 
> Thanks,
> ta
> 
>>
>> Signed-off-by: Michael Walle <michael@walle.cc>
>> ---
>>  drivers/mtd/spi-nor/core.c | 7 +++++--
>>  drivers/mtd/spi-nor/core.h | 9 +++++++++
>>  2 files changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
>> index 402b37cdbcea..29329ed0a934 100644
>> --- a/drivers/mtd/spi-nor/core.c
>> +++ b/drivers/mtd/spi-nor/core.c
>> @@ -2104,8 +2104,11 @@ static int spi_nor_select_pp(struct spi_nor *nor,
>>   * spi_nor_select_uniform_erase() - select optimum uniform erase type
>>   * @map:               the erase map of the SPI NOR
>>   * @wanted_size:       the erase type size to search for. Contains the value of
>> - *                     info->sector_size or of the "small sector" size in case
>> - *                     CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is defined.
>> + *                     info->sector_size, the "small sector" size in case
>> + *                     CONFIG_MTD_SPI_NOR_USE_4K_SECTORS is defined or 0 if
>> + *                     there is no information about the sector size. The
>> + *                     latter is the case if the flash parameters are parsed
>> + *                     solely by SFDP.
>>   *
>>   * Once the optimum uniform sector erase command is found, disable all the
>>   * other.
>> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
>> index 61886868cd02..fab3038c4f4a 100644
>> --- a/drivers/mtd/spi-nor/core.h
>> +++ b/drivers/mtd/spi-nor/core.h
>> @@ -563,6 +563,15 @@ struct flash_info {
>>                         .n_regions = (_n_regions),                      \
>>                 },
>>
>> +#define SNOR_ID3(_jedec_id)

How about SFDP_ID3 and SFDP_ID6 instead?

                                            \
>> +               .id = {                                                 \
>> +                       ((_jedec_id) >> 16) & 0xff,                     \
>> +                       ((_jedec_id) >> 8) & 0xff,                      \
>> +                       (_jedec_id) & 0xff,                             \
>> +                       },                                              \
>> +               .id_len = 3,                                            \
>> +               .parse_sfdp = true,                                     \
>> +
>>  #define PARSE_SFDP                                                     \
>>         .parse_sfdp = true,                                             \
>>
>> --
>> 2.30.2
>>
> 
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-- 
Cheers,
ta