Re: [PATCH v2] mtd: spinand: add support for ESMT F50x1G41LB

[Ezra Buehler]

Hi Chuanhong Guo,

On Wed, 13 Apr 2022 22:50:43 +0800 Chuanhong Guo <gch981213@xxxxxxxxx> wrote:
> Their device ID aren't conflicting yet, so nothing will happen
> at the moment.

Since commit aa08bf187f32 ("mtd: spinand: esmt: add support for
F50D2G41KA") we have a conflict with the GigaDevice GD5F1GQ5UExxG
(manufacturer ID 0xC8, device ID 0x51), preventing our board from
booting.

> There is a solution for future conflict: Recent SPI-NAND chips
> contain a parameter page which has the exact chip vendor
> and model. We can do one more detection with the parameter
> page content.
> Winbond W25N01KV is a 2k+96 SPI-NAND with 4-bit ECC.
> It uses the exact same chip id as the current W25N01GV
> (2k+64 1-bit ECC). We need to support detection using
> parameter page for this crazy decision by Winbond anyway.
> I'll try to code something for this with my free time.
>
> My current idea is: We first do a detection based on chip id.
> If that failed, try to read the parameter page. If we got a
> valid one, match the chip vendor and model string.

According to the datasheets, the ESMT chips actually have a 5 byte ID,
the last 3 bytes being 0x7F (JEDEC Maker Code Continuation Code). Why
can't we simply extend the ID in esmt.c (as you had it in your original
patch) and increase SPINAND_MAX_ID_LEN to 5? Or, alternatively, only
extend the ID to 4 bytes?

If that is the way to go, I would be happy to provide the patches.

Cheers,
Ezra.