On Mon, 29 Apr 2019 at 19:32, Raul E Rangel <rrangel@xxxxxxxxxxxx> wrote: > > The SD Physical Layer Spec says the following: Since the SD Memory Card > shall support at least the two bus modes 1-bit or 4-bit width, then any SD > Card shall set at least bits 0 and 2 (SD_BUS_WIDTH="0101"). > > This change verifies the card has specified a bus width. > > AMD SDHC Device 7806 can get into a bad state after a card disconnect > where anything transferred via the DATA lines will always result in a > zero filled buffer. Currently the driver will continue without error if > the HC is in this condition. A block device will be created, but reading > from it will result in a zero buffer. This makes it seem like the SD > device has been erased, when in actuality the data is never getting > copied from the DATA lines to the data buffer. > > SCR is the first command in the SD initialization sequence that uses the > DATA lines. By checking that the response was invalid, we can abort > mounting the card. > > Acked-by: Avri Altman <avri.altman@xxxxxxx> > Reviewed-by: Avri Altman <avri.altman@xxxxxxx> No need for both ack/review tags, the latter is superior so keeping only that. > > Signed-off-by: Raul E Rangel <rrangel@xxxxxxxxxxxx> Applied for next, thanks! Let's how the testing turns out, we may consider sending a backport to stable later on. Kind regards Uffe > --- > Here is the testing I did: > > Good Trace: https://paste.fedoraproject.org/paste/oVEI5b0IzHD23Yo7CDZgEg > [ 30.103686] mmc0: new high speed SDHC card at address 0001 > [ 30.105262] mmcblk0: mmc0:0001 00000 7.41 GiB > [ 30.108258] mmcblk0: p1 > [ 31.947250] mmc0: card 0001 removed > > Bad Trace (before patch): https://paste.fedoraproject.org/paste/jBWfpFBM8gdEmGOzxij~hw > > Bad Trace (after patch): https://paste.fedoraproject.org/paste/8gB8MLYOKEUZEgHXmQ0W1Q > [ 33.810760] mmc0: invalid bus width > [ 33.810782] mmc0: error -22 whilst initialising SD card > [ 34.068818] mmc0: invalid bus width > [ 34.068839] mmc0: error -22 whilst initialising SD card > [ 34.329521] mmc0: invalid bus width > [ 34.329543] mmc0: error -22 whilst initialising SD card > [ 34.592061] mmc0: invalid bus width > [ 34.592084] mmc0: error -22 whilst initialising SD card > > In the traces you can see sd_scr is different > > Changes in v3: > - Rebased on mmc/next > > Changes in v2: > - Made the bus width check stricter. It now requires the value to match > the spec. > > drivers/mmc/core/sd.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c > index 265e1aeeb9d8..d3d32f9a2cb1 100644 > --- a/drivers/mmc/core/sd.c > +++ b/drivers/mmc/core/sd.c > @@ -221,6 +221,14 @@ static int mmc_decode_scr(struct mmc_card *card) > > if (scr->sda_spec3) > scr->cmds = UNSTUFF_BITS(resp, 32, 2); > + > + /* SD Spec says: any SD Card shall set at least bits 0 and 2 */ > + if (!(scr->bus_widths & SD_SCR_BUS_WIDTH_1) || > + !(scr->bus_widths & SD_SCR_BUS_WIDTH_4)) { > + pr_err("%s: invalid bus width\n", mmc_hostname(card->host)); > + return -EINVAL; > + } > + > return 0; > } > > -- > 2.21.0.593.g511ec345e18-goog >
