On Thu, 12 Mar 2020 at 15:25, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
>
> Switching from HS400 to HS200 may experience CRC errors. Do not check
> CRC response in that case.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
[...]
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index 619088a94688..2baaa66e491d 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -552,12 +552,13 @@ int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
> * @timing: new timing to change to
> * @send_status: send status cmd to poll for busy
> * @retry_crc_err: retry when CRC errors when polling with CMD13 for busy
> + * @no_crc_resp: do not require to check CRC response
> *
> * Modifies the EXT_CSD register for selected card.
> */
> int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
> unsigned int timeout_ms, unsigned char timing,
> - bool send_status, bool retry_crc_err)
> + bool send_status, bool retry_crc_err, bool no_crc_resp)
> {
> struct mmc_host *host = card->host;
> int err;
> @@ -594,6 +595,8 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
> } else {
> cmd.flags |= MMC_RSP_SPI_R1 | MMC_RSP_R1;
> }
> + if (no_crc_resp)
> + cmd.flags &= ~MMC_RSP_CRC;
So potentially this means the host driver will complete the command
successfully, even if it receives a CRC error.
As I understood it, the idea was to poll for busy, *if* we encountered
CRC errors, so then how would you know about that?
Seems like we should drop the above code and be checking for -EILSEQ
of the request instead? No?
>
> if (index == EXT_CSD_SANITIZE_START)
> cmd.sanitize_busy = true;
> @@ -639,7 +642,7 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
> unsigned int timeout_ms)
> {
> return __mmc_switch(card, set, index, value, timeout_ms, 0,
> - true, false);
> + true, false, false);
> }
> EXPORT_SYMBOL_GPL(mmc_switch);
>
> diff --git a/drivers/mmc/core/mmc_ops.h b/drivers/mmc/core/mmc_ops.h
> index 38dcfeeaf6d5..1a75c347b8a7 100644
> --- a/drivers/mmc/core/mmc_ops.h
> +++ b/drivers/mmc/core/mmc_ops.h
> @@ -40,7 +40,7 @@ int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
> enum mmc_busy_cmd busy_cmd);
> int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
> unsigned int timeout_ms, unsigned char timing,
> - bool send_status, bool retry_crc_err);
> + bool send_status, bool retry_crc_err, bool no_crc_resp);
> int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
> unsigned int timeout_ms);
> void mmc_run_bkops(struct mmc_card *card);
> --
> 2.17.1
>
Kind regards
Uffe
