linux-kernel - [PATCH v3 2/4] mtd: rawnand: Fix nand_choose_best

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Message-Id: <20211119150316.43080-3-herve.codina@bootlin.com>
Date:   Fri, 19 Nov 2021 16:03:14 +0100
From:   Herve Codina <herve.codina@...tlin.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>
Cc:     linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Herve Codina <herve.codina@...tlin.com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: [PATCH v3 2/4] mtd: rawnand: Fix nand_choose_best_timings() on unsupported interface

When the NV-DDR interface is not supported by the NAND chip,
the value of onfi->nvddr_timing_modes is 0. In this case,
the best_mode variable value in nand_choose_best_nvddr_timings()
is -1. The last for-loop is skipped and the function returns an
uninitialized value.
If this returned value is 0, the nand_choose_best_sdr_timings()
is not executed and no 'best timing' are set. This leads the host
controller and the NAND chip working at default mode 0 timing
even if a better timing can be used.

Fix this uninitialized returned value.

nand_choose_best_sdr_timings() is pretty similar to
nand_choose_best_nvddr_timings(). Even if onfi->sdr_timing_modes
should never be seen as 0, nand_choose_best_sdr_timings() returned
value is fixed.

Fixes: a9ecc8c814e9 ("mtd: rawnand: Choose the best timings, NV-DDR included")
Signed-off-by: Herve Codina <herve.codina@...tlin.com>
---
Changes v1 to v2:
- New patch in v2 series

Changes v2 -> v3:
- Fix commit log typo

 drivers/mtd/nand/raw/nand_base.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 5c6b065837ef..a130320de412 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -926,7 +926,7 @@ int nand_choose_best_sdr_timings(struct nand_chip *chip,
 				 struct nand_sdr_timings *spec_timings)
 {
 	const struct nand_controller_ops *ops = chip->controller->ops;
-	int best_mode = 0, mode, ret;
+	int best_mode = 0, mode, ret = -EOPNOTSUPP;

 	iface->type = NAND_SDR_IFACE;

@@ -977,7 +977,7 @@ int nand_choose_best_nvddr_timings(struct nand_chip *chip,
 				   struct nand_nvddr_timings *spec_timings)
 {
 	const struct nand_controller_ops *ops = chip->controller->ops;
-	int best_mode = 0, mode, ret;
+	int best_mode = 0, mode, ret = -EOPNOTSUPP;

 	iface->type = NAND_NVDDR_IFACE;

-- 
2.31.1