Hello Miquel,
Am Tue, May 07, 2024 at 06:05:45PM +0200 schrieb Miquel Raynal:
> 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@xxxxxxxxxxxxxxx
> Reported-by: Alexander Dahl <ada@xxxxxxxxxxx>
> Closes: https://lore.kernel.org/linux-mtd/20240306-shaky-bunion-d28b65ea97d7@xxxxxxxxxxx/
> Reported-by: Steven Seeger <steven.seeger@xxxxxxxxxxxxxxxxx>
> Closes: https://lore.kernel.org/linux-mtd/DM6PR05MB4506554457CF95191A670BDEF7062@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
> Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
> ---
> 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)) {
Thanks for tacking care of this.
Reviewed-by: Alexander Dahl <ada@xxxxxxxxxxx>
Greets
Alex
