From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Alexander Dahl <ada@thorsis.com>
Cc: linux-mtd@lists.infradead.org,
Richard Weinberger <richard@nod.at>,
Vignesh Raghavendra <vigneshr@ti.com>,
linux-kernel@vger.kernel.org
Subject: Re: mtd: nand: raw: Possible bug in nand_onfi_detect()?
Date: Tue, 7 May 2024 18:08:08 +0200 [thread overview]
Message-ID: <20240507180808.7f252532@xps-13> (raw)
In-Reply-To: <20240306-shaky-bunion-d28b65ea97d7@thorsis.com>
Hello,
ada@thorsis.com wrote on Wed, 6 Mar 2024 15:36:04 +0100:
> Hello everyone,
>
> I think I found a bug in nand_onfi_detect() which was introduced with
> commit c27842e7e11f ("mtd: rawnand: onfi: Adapt the parameter page
> read to constraint controllers") back in 2020.
>
> Background on how I found this: I'm currently struggling getting raw
> nand flash access to fly with an at91 sam9x60 SoC and a S34ML02G1
> Spansion SLC raw NAND flash on a custom board. The setup is
> comparable to the sam9x60 curiosity board and can be reproduced with
> that one.
>
> NAND flash on sam9x60 curiosity board works fine with what is in
> mainline Linux kernel. However after removing the line 'rb-gpios =
> <&pioD 5 GPIO_ACTIVE_HIGH>;' from at91-sam9x60_curiosity.dts all data
> read from the flash appears to be zeros only. (I did not add that
> line to the dts of my custom board first, this is how I stumbled over
> this.)
>
> I have no explanation for that behaviour, it should work without R/B#
> by reading the status register, maybe we investigate that
> in depth later. However those all zeros data reads happens when
> reading the ONFI param page as well es data read from OOB/spare area
> later and I bet it's the same with usual data.
>
> This read error reveals a bug in nand_onfi_detect(). After setting
> up some things there's this for loop:
>
> for (i = 0; i < ONFI_PARAM_PAGES; i++) {
>
> For i = 0 nand_read_param_page_op() is called and in my case all zeros
> are returned and thus the CRC calculated does not match the all zeros
> CRC read. So the usual break on successful reading the first page is
> skipped and for reading the second page nand_change_read_column_op()
> is called. I think that one always fails on this line:
>
> if (offset_in_page + len > mtd->writesize + mtd->oobsize) {
>
> Those variables contain the following values:
>
> offset_in_page: 256
> len: 256
> mtd->writesize: 0
> mtd->oobsize: 0
>
> The condition is true and nand_change_read_column_op() returns with
> -EINVAL, because mtd->writesize and mtd->oobsize are not set yet in
> that code path. Those are probably initialized later, maybe with
> parameters read from that ONFI param page?
>
> Returning with error from nand_change_read_column_op() leads to
> jumping out of nand_onfi_detect() early, and no ONFI param page is
> evaluated at all, although the second or third page could be intact.
>
> I guess this would also fail with any other reason for not matching
> CRCs in the first page, but I have not faulty NAND flash chip to
> confirm that.
Sorry for the time it took on my side.
Here is a link to another similar report:
https://lore.kernel.org/linux-mtd/DM6PR05MB4506554457CF95191A670BDEF7062@DM6PR05MB4506.namprd05.prod.outlook.com/
And here is a link to the series attempting to fix this:
https://lore.kernel.org/linux-mtd/20240507160546.130255-1-miquel.raynal@bootlin.com/T/#t
Thanks,
Miquèl
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
prev parent reply other threads:[~2024-05-07 16:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-06 14:36 mtd: nand: raw: Possible bug in nand_onfi_detect()? Alexander Dahl
2024-03-06 15:48 ` Miquel Raynal
2024-03-07 16:02 ` Alexander Dahl
2024-03-07 17:19 ` Miquel Raynal
2024-03-25 9:09 ` Miquel Raynal
2024-03-25 9:59 ` Alexander Dahl
2024-05-07 16:08 ` Miquel Raynal [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240507180808.7f252532@xps-13 \
--to=miquel.raynal@bootlin.com \
--cc=ada@thorsis.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mtd@lists.infradead.org \
--cc=richard@nod.at \
--cc=vigneshr@ti.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).