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From: Alexander Sverdlin <alexander.sverdlin@nokia.com>
To: Michael Walle <michael@walle.cc>
Cc: linux-mtd@lists.infradead.org,
	Tudor Ambarus <tudor.ambarus@microchip.com>,
	Pratyush Yadav <p.yadav@ti.com>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mtd: spi-nor: mt25qu: Ignore 6th ID byte
Date: Tue, 23 Nov 2021 13:13:07 +0100	[thread overview]
Message-ID: <85251c3b-13c1-8b24-0ce2-6793ea55e39a@nokia.com> (raw)
In-Reply-To: <e9589af968d7b9dafbce17325dbf8472@walle.cc>

Dear maintainers!

On 22/11/2021 16:05, Michael Walle wrote:
> Thanks, so that's the SFDP data for the mt25qu256aba8e12-1sit part. and the
> jedec id is 20bb19104473, correct?

While we are at this part, I've encountered another issue:

The chip supports 1-1-1, 1-1-4 and 1-4-4 write OPs in extended SPI mode,
while only 1-1-0 erase. (as well as 4-4-4/4-4-0, but that's not the issue here,
I think).

Now the erase code (chip/sector) uses spi_nor_spimem_setup_op(nor, &op, nor->write_proto)
in both functions.

In my opinion, as I look into Micron or Macronix datasheets, write_proto has little to
do with erase_proto. (there is currently no separate erase_proto)

Before I come up with a totally wrong patch, wanted to ask your opinion, how should
it be solved, what do you think?

I do not see any erase-related tables for this in JESD216C.
I also cannot come up with an example of a chip with erase != 1-1-0.

Shall I hardcode 1-1-0 for erase?
Shall I introduce erase_proto? What would be the logic for its setting/discovery?

-- 
Best regards,
Alexander Sverdlin.

  parent reply	other threads:[~2021-11-23 12:13 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-19  8:04 Alexander A Sverdlin
2021-11-19 21:19 ` Michael Walle
2021-11-22  7:06   ` Alexander Sverdlin
2021-11-22 15:05     ` Michael Walle
2021-11-23  7:45       ` Alexander Sverdlin
2021-11-23  8:14         ` Michael Walle
2021-11-23 12:40           ` Alexander Sverdlin
2021-11-23 14:01             ` Michael Walle
2021-11-23 16:14               ` Tudor.Ambarus
2021-11-23 12:13       ` Alexander Sverdlin [this message]
2021-11-23 17:42         ` Pratyush Yadav
2021-11-25  7:26           ` Alexander Sverdlin
2021-11-30  9:49             ` Pratyush Yadav
2022-07-18 15:03 ` Tudor.Ambarus

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