> > 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. > > verified it didn't mount. > > Signed-off-by: Raul E Rangel <rrangel@xxxxxxxxxxxx> Acked-by: Avri Altman <avri.altman@xxxxxxx> > --- > 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. > > Here is an example of a bad trace: https://pastebin.com/TY2cF9n0 > Look for sd_scr and sd_ssr. > > drivers/mmc/core/sd.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c > index 265e1aeeb9d8..f6481f8e9fe7 100644 > --- a/drivers/mmc/core/sd.c > +++ b/drivers/mmc/core/sd.c > @@ -205,6 +205,13 @@ static int mmc_decode_scr(struct mmc_card *card) > > scr->sda_vsn = UNSTUFF_BITS(resp, 56, 4); > scr->bus_widths = UNSTUFF_BITS(resp, 48, 4); > + > + /* SD Spec says: any SD Card shall set at least bits 0 and 2 */ > + if (!scr->bus_widths) { So why not testing that exact mask? you have SD_SCR_BUS_WIDTH_1 and SD_SCR_BUS_WIDTH_4 already defined...
