The nand_read_data_op() operation, which only consists in DATA_IN cycles, is sadly not supported by all controllers despite being very basic. The core, for some time, supposed all drivers would support it. An improvement to this situation for supporting more constrained controller added a check to verify if the operation was supported before attempting it by running the function with the check_only boolean set first, and then possibly falling back to another (possibly slightly less optimized) alternative.

An even newer addition moved that check very early and probe time, in order to perform the check only once. The content of the operation was not so important, as long as the controller driver would tell whether such operation on the NAND bus would be possible or not. In practice, no buffer was provided (no fake buffer or whatever) as it is anyway not relevant for the "check_only" condition. Unfortunately, early in the function, there is an if statement verifying that the input parameters are right for normal use, making the early check always unsuccessful.

Fixes: 9f820fc0651c ("mtd: rawnand: Check the data only read pattern only once") Cc: stable@vger.kernel.org Reported-by: Alexander Dahl ada@thorsis.com Closes: https://lore.kernel.org/linux-mtd/20240306-shaky-bunion-d28b65ea97d7@thorsis... Reported-by: Steven Seeger steven.seeger@flightsystems.net Closes: https://lore.kernel.org/linux-mtd/DM6PR05MB4506554457CF95191A670BDEF7062@DM6... Signed-off-by: Miquel Raynal miquel.raynal@bootlin.com Reviewed-by: Alexander Dahl ada@thorsis.com --- drivers/mtd/nand/raw/nand_base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c index acd137dd0957..248e654ecefd 100644 --- a/drivers/mtd/nand/raw/nand_base.c +++ b/drivers/mtd/nand/raw/nand_base.c @@ -2173,7 +2173,7 @@ EXPORT_SYMBOL_GPL(nand_reset_op); int nand_read_data_op(struct nand_chip *chip, void *buf, unsigned int len, bool force_8bit, bool check_only) { - if (!len || !buf) + if (!len || (!check_only && !buf)) return -EINVAL;

if (nand_has_exec_op(chip)) {