[PATCH v4 4/6] mtd: spi-nor: macronix: Handle ID collision b/w MX25L12805D and MX25L12835F

[Heiko Thiery]

Hi Tudor,

Am Mo., 28. Feb. 2022 um 14:45 Uhr schrieb Tudor Ambarus
<tudor.ambarus at microchip.com>:
>
> Macronix has a bad habbit of reusing flash IDs. While MX25L12835F supports
> RDSFDP opcode, MX25L12805D does not. Given that it is unlikely that RDSFDP
> will cause any problems for the old MX25L12805D, differentiate between the
> two flashes by parsing SFDP.
>
> cc: Heiko Thiery <heiko.thiery at gmail.com>
> Signed-off-by: Tudor Ambarus <tudor.ambarus at microchip.com>
> Acked-by: Pratyush Yadav <p.yadav at ti.com>
> ---
> # cat /sys/devices/platform/soc at 0/30800000.bus/30bb0000.spi/spi_master/spi0/spi0
> .0/spi-nor/sfdp | xxd -p
> 53464450000101ff00000109300000ffc2000104600000ffffffffffffff
> ffffffffffffffffffffffffffffffffffffe520f1ffffffff0744eb086b
> 083b04bbfeffffffffff00ffffff44eb0c200f5210d800ffffffffffffff
> ffffffffffff003600279df9c06485cbffffffffffff
>
>  drivers/mtd/spi-nor/macronix.c | 23 ++++++++++++++++++++++-
>  1 file changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/spi-nor/macronix.c b/drivers/mtd/spi-nor/macronix.c
> index 2754bbef3d2e..45c2f2c50e56 100644
> --- a/drivers/mtd/spi-nor/macronix.c
> +++ b/drivers/mtd/spi-nor/macronix.c
> @@ -26,6 +26,24 @@ static const struct spi_nor_fixups mx25l3205d_fixups = {
>         .post_bfpt = mx25l3205d_post_bfpt_fixups,
>  };
>
> +static int mx25l12805d_post_bfpt_fixups(struct spi_nor *nor,
> +                               const struct sfdp_parameter_header *bfpt_header,
> +                               const struct sfdp_bfpt *bfpt)
> +{
> +       /*
> +        * Macronix has a bad habit of reusing flash IDs: MX25L12835F collides
> +        * with MX25L12805D. MX25L12835F defines SFDP tables, while the older
> +        * variant does not.
> +        */
> +       nor->name = "mx25l12835f";
> +
> +       return 0;
> +}
> +
> +static const struct spi_nor_fixups mx25l12805d_fixups = {
> +       .post_bfpt = mx25l12805d_post_bfpt_fixups,
> +};
> +
>  static int
>  mx25l25635_post_bfpt_fixups(struct spi_nor *nor,
>                             const struct sfdp_parameter_header *bfpt_header,
> @@ -82,8 +100,11 @@ static const struct flash_info macronix_nor_parts[] = {
>         { "mx25u6435f",  INFO(0xc22537, 0, 64 * 1024, 128)
>                 NO_SFDP_FLAGS(SECT_4K) },
>         { "mx25l12805d", INFO(0xc22018, 0, 64 * 1024, 256)
> +               /* ID collision with mx25l12835f. */
> +               PARSE_SFDP
>                 FLAGS(SPI_NOR_HAS_LOCK | SPI_NOR_4BIT_BP)
> -               NO_SFDP_FLAGS(SECT_4K) },
> +               NO_SFDP_FLAGS(SECT_4K)
> +               .fixups = &mx25l12805d_fixups },
>         { "mx25l12855e", INFO(0xc22618, 0, 64 * 1024, 256) },
>         { "mx25r1635f",  INFO(0xc22815, 0, 64 * 1024,  32)
>                 NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ |
> --
> 2.25.1
>

I tried this patch and saw that the flash is no longer detected. I did
some debugging and see now that the correct function to set the quad
mode (spi_nor_sr1_bit6_quad_enable) is not called. Instead the
spi_nor_sr2_bit1_quad_enable() is invoked. Further debbuging showed me
that the macronix specific fixup is not called.

For the flash that does support SFDP parsing the
spi_nor_manufacturer_init_params() is not called. Is that expected to
be?

--
Heiko