Re: [PATCH v2 2/2] mtd: rawnand: Bypass a couple of sanity checks during NAND identification

From: Sascha Hauer <s.hauer@pengutronix.de>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Tudor Ambarus <tudor.ambarus@linaro.org>,
	Pratyush Yadav <pratyush@kernel.org>,
	Michael Walle <michael@walle.cc>,
	linux-mtd@lists.infradead.org, Alexander Dahl <ada@thorsis.com>,
	Steven Seeger <steven.seeger@flightsystems.net>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH v2 2/2] mtd: rawnand: Bypass a couple of sanity checks during NAND identification
Date: Thu, 16 May 2024 15:51:49 +0200	[thread overview]
Message-ID: <ZkYPdbspX5tc0WRf@pengutronix.de> (raw)
In-Reply-To: <20240516131320.579822-3-miquel.raynal@bootlin.com>

On Thu, May 16, 2024 at 03:13:20PM +0200, Miquel Raynal wrote:
> Early during NAND identification, mtd_info fields have not yet been
> initialized (namely, writesize and oobsize) and thus cannot be used for
> sanity checks yet. Of course if there is a misuse of
> nand_change_read_column_op() so early we won't be warned, but there is
> anyway no actual check to perform at this stage as we do not yet know
> the NAND geometry.
> 
> So, if the fields are empty, especially mtd->writesize which is *always*
> set quite rapidly after identification, let's skip the sanity checks.
> 
> nand_change_read_column_op() is subject to be used early for ONFI/JEDEC
> identification in the very unlikely case of:
> - bitflips appearing in the parameter page,
> - the controller driver not supporting simple DATA_IN cycles.
> 
> As nand_change_read_column_op() uses nand_fill_column_cycles() the logic
> explaind above also applies in this secondary helper.
> 
> Fixes: c27842e7e11f ("mtd: rawnand: onfi: Adapt the parameter page read to constraint controllers")
> Fixes: daca31765e8b ("mtd: rawnand: jedec: Adapt the parameter page read to constraint controllers")
> Cc: stable@vger.kernel.org
> Reported-by: Alexander Dahl <ada@thorsis.com>
> Closes: https://lore.kernel.org/linux-mtd/20240306-shaky-bunion-d28b65ea97d7@thorsis.com/
> Reported-by: Steven Seeger <steven.seeger@flightsystems.net>
> Closes: https://lore.kernel.org/linux-mtd/DM6PR05MB4506554457CF95191A670BDEF7062@DM6PR05MB4506.namprd05.prod.outlook.com/
> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>

With the attached debug patch applied I can confirm that I can now read
all three ONFI parameter pages successfully using
nand_change_read_column_op(), so:

Tested-by: Sascha Hauer <s.hauer@pengutronix.de>

Sascha

-----------------------------------8<--------------------------------------

diff --git a/drivers/mtd/nand/raw/nand_onfi.c b/drivers/mtd/nand/raw/nand_onfi.c
index 861975e44b552..ca6b4bf426750 100644
--- a/drivers/mtd/nand/raw/nand_onfi.c
+++ b/drivers/mtd/nand/raw/nand_onfi.c
@@ -180,6 +180,9 @@ int nand_onfi_detect(struct nand_chip *chip)
 			ret = nand_change_read_column_op(chip, sizeof(*pbuf) * i,
 							 &pbuf[i], sizeof(*pbuf),
 							 true);
+
+		print_hex_dump(KERN_INFO, "onfi: ", DUMP_PREFIX_OFFSET, 16, 1, &pbuf[i], sizeof(*pbuf), true);
+
 		if (ret) {
 			ret = 0;
 			goto free_onfi_param_page;
@@ -188,7 +191,6 @@ int nand_onfi_detect(struct nand_chip *chip)
 		crc = onfi_crc16(ONFI_CRC_BASE, (u8 *)&pbuf[i], 254);
 		if (crc == le16_to_cpu(pbuf[i].crc)) {
 			p = &pbuf[i];
-			break;
 		}
 	}
 
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