[RFC PATCH 1/2] mtd: rawnand: handle ONFI revision number field being 0

From: Chris Packham <chris.packham@alliedtelesis.co.nz>
To: miquel.raynal@bootlin.com, boris.brezillon@bootlin.com,
	dwmw2@infradead.org, computersforpeace@gmail.com,
	linux-mtd@lists.infradead.org
Cc: linux-kernel@vger.kernel.org,
	Chris Packham <chris.packham@alliedtelesis.co.nz>,
	Richard Weinberger <richard@nod.at>,
	Marek Vasut <marek.vasut@gmail.com>
Subject: [RFC PATCH 1/2] mtd: rawnand: handle ONFI revision number field being 0
Date: Mon, 18 Jun 2018 16:52:54 +1200	[thread overview]
Message-ID: <20180618045255.8015-2-chris.packham@alliedtelesis.co.nz> (raw)
In-Reply-To: <20180618045255.8015-1-chris.packham@alliedtelesis.co.nz>

Some Micron NAND chips (MT29F1G08ABAFAWP-ITE:F) report 00 00 for the
revision number field of the ONFI parameter page. Rather than rejecting
these outright assume ONFI version 1.0 if the revision number is 00 00.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
At the moment I haven't qualified this check on anything, I should
probably at least include vendor == MICRON.

As far as I can tell revision number == 0 is not permitted by the ONFI
spec but this wouldn't be the first time a vendor has ignored a spec. On
the other hand maybe I'm reading the spec wrong and someone here will
say "oh 0 means ...".

 drivers/mtd/nand/raw/nand_base.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 0cd3e216b95c..1691c7005ae4 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -5184,6 +5184,8 @@ static int nand_flash_detect_onfi(struct nand_chip *chip)
 		chip->parameters.onfi.version = 20;
 	else if (val & (1 << 1))
 		chip->parameters.onfi.version = 10;
+	else if (val == 0)
+		chip->parameters.onfi.version = 10;
 
 	if (!chip->parameters.onfi.version) {
 		pr_info("unsupported ONFI version: %d\n", val);
-- 
2.17.1

