Hi Stefan, On 1/29/21 4:23 AM, Stefan Bosch wrote: > Hi, > > On 27.01.21 00:38, Jaehoon Chung wrote: >> Hi, >> >> On 1/23/21 9:37 PM, Stefan Bosch wrote: >>> After issuing the switch command: Wait until 'current state' of the card >>> status becomes 'tran'. This prevents from response timeout at the next >>> command because of 'current state' = 'data'.> >>> Signed-off-by: Stefan Bosch <stefa...@posteo.net> >>> --- >>> >>> drivers/mmc/mmc.c | 3 ++- >>> include/mmc.h | 1 + >>> 2 files changed, 3 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c >>> index a47700e313..8ccd2058a9 100644 >>> --- a/drivers/mmc/mmc.c >>> +++ b/drivers/mmc/mmc.c >>> @@ -823,7 +823,8 @@ static int __mmc_switch(struct mmc *mmc, u8 set, u8 >>> index, u8 value, >>> value); >>> return -EIO; >>> } >>> - if (!ret && (status & MMC_STATUS_RDY_FOR_DATA)) >>> + if (!ret && (status & MMC_STATUS_RDY_FOR_DATA) && >>> + (status & MMC_STATUS_CURR_STATE) == MMC_STATE_TRANS) >> >> AFAIK, MMC_STATUS_RDY_FOR_DATA bit means the signaling about "buffer is >> empty". >> Even though its bit was set, does it need to check TRANS state? >> >> Best Regards, >> Jaehoon Chung >> > > After issuing command 'MMC_CMD_SWITCH' = CMD6 the state transits to 'DATA'. > But in DATA state it is not possible to issue a (new) CMD except CMD12 > (operation complete) and CMD7 (select/deselect card). See appropriate State > Diagram, e.g. "Figure 4-3: SD Memory Card State Diagram (data transfer mode)" > in "SD Specifications Part 1 - Physical Layer - Simplified Specification - > Version 2.00". Status 'Ready For Data' is in my opinion only relevant for > CMD12 and CMD7.
Thanks for explanation. I have checked Spec about SD and eMMC. It makes sense. Reviewed-by: Jaehoon Chung <jh80.ch...@samsung.com> Best Regards, Jaehoon Chung > > Regards > Stefan Bosch > >>> return 0; >>> udelay(100); >>> } while (get_timer(start) < timeout_ms); >>> diff --git a/include/mmc.h b/include/mmc.h >>> index 1d377e0281..18402494c6 100644 >>> --- a/include/mmc.h >>> +++ b/include/mmc.h >>> @@ -178,6 +178,7 @@ static inline bool mmc_is_tuning_cmd(uint cmdidx) >>> #define MMC_STATUS_ERROR (1 << 19) >>> #define MMC_STATE_PRG (7 << 9) >>> +#define MMC_STATE_TRANS (4 << 9) >>> #define MMC_VDD_165_195 0x00000080 /* VDD voltage 1.65 - 1.95 >>> */ >>> #define MMC_VDD_20_21 0x00000100 /* VDD voltage 2.0 ~ 2.1 */ >>> >> >