Hi Shawn,
On Wed, Aug 16, 2017 at 09:11:41AM +0800, Shawn Lin wrote:
> We to some extent should tolerate R1_OUT_OF_RANGE for open-ending
> mode as it is expected behaviour and most of the backup partition
> tables should be located near some of the last blocks which will
> always make open-ending read exceed the capacity of cards.
>
> Fixes: 9820a5b11101 ("mmc: core: for data errors, take response of stop cmd into account")
> Fixes: a04e6bae9e6f ("mmc: core: check also R1 response for stop commands")
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
>
> Tested-by: Shawn Guo <shawnguo@xxxxxxxxxx>
> Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
I'd think these Tested-by should be dropped. We changed the patch quite
a bit meanwhile and I am quite sure Shimoda-san didn't test this new
version of the patch. Dunno about Shawn. Hopefully they have time to
re-test?
> + /*
> + * Per the SD specification(physical layer version 4.10)[1],
> + * section 4.3.3, it explicitly states that "When the last
> + * block of user area is read using CMD18, the host should
> + * ignore OUT_OF_RANGE error that may occur even the sequence
> + * is correct". And JESD84-B51 for eMMC also has a similar
> + * statement on section 6.8.3.
> + *
> + * Multiple block read/write could be done by either predefined
> + * method, namely CMD23, or open-ending mode.
> + *
Very minor nit: I'd remove this empty line and merge the two paragraphs.
> + * For open-ending mode, we should ignore the OUT_OF_RANGE
> + * error as it's normal behaviour.
> + *
> + * However the spec[1] doesn't tell us whether we should also
> + * ignore that for predefined method. But per the spec[1], section
> + * 4.15 Set Block Count Command, it says"If illegal block count
> + * is set, out of range error will be indicated during read/write
> + * operation (For example, data transfer is stopped at user area
> + * boundary)." In another word, we could expect a out of range error
> + * in the response for the following CMD18/25. And if argument of
> + * CMD23 + the argument of CMD18/25 exceed the max number of blocks,
> + * we could also expect to get a -ETIMEDOUT or any error number from
> + * the host drivers due to missing data response(for write)/data(for
> + * read), as the cards will stop the data transfer by itself per the
> + * spec. So we only need to check R1_OUT_OF_RANGE for open-ending mode.
> + */
Very good! I like this a lot.
Also minor nit, but likely better readable:
> +
> + if (!brq->stop.error) {
bool OOR_with_open_end;
> + /* If there is no error yet, check R1 response */
> + val = brq->stop.resp[0] & CMD_ERRORS;
OOR_with_open_end = val & R1_OUT_OF_RANGE && !brq->mrq.sbc;
if (val && !OOR_with_open_end)
> + brq->stop.error = -EIO;
...
> + if (brq->sbc.error || brq->cmd.error ||
> + brq->stop.error || brq->data.error) {
I am not super strict with the 80 char limit and think one line is
better readable, but I leave that to you and/or Ulf.
Other than that minor stuff:
Reviewed-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Thanks for this collaboration! I liked it :)
Regards,
Wolfram
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