Commit ef3d2322 authored by Adrian Hunter's avatar Adrian Hunter Committed by Ulf Hansson
Browse files

mmc: mmc: Relax checking for switch errors after HS200 switch 



The JEDEC specification indicates CMD13 can be used after a HS200 switch
to check for errors. However in practice some boards experience CRC errors
in the CMD13 response. Consequently, for HS200, CRC errors are not a
reliable way to know the switch failed. If there really is a problem, we
would expect tuning will fail and the result ends up the same. So change
the error condition to ignore CRC errors in that case.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Acked-by: default avatarJaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: default avatarShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent db52d4f8

drivers/mmc/core/mmc.c

+13 −2
Original line number Diff line number Diff line
@@ -1240,7 +1240,12 @@ int mmc_hs400_to_hs200(struct mmc_card *card) 


	mmc_set_timing(host, MMC_TIMING_MMC_HS200);



	err = mmc_switch_status(card);

	/*

	 * For HS200, CRC errors are not a reliable way to know the switch

	 * failed. If there really is a problem, we would expect tuning will

	 * fail and the result ends up the same.

	 */

	err = __mmc_switch_status(card, false);

	if (err)

		goto out_err;
@@ -1403,7 +1408,13 @@ static int mmc_select_hs200(struct mmc_card *card) 
		old_timing = host->ios.timing;

		mmc_set_timing(host, MMC_TIMING_MMC_HS200);



		err = mmc_switch_status(card);

		/*

		 * For HS200, CRC errors are not a reliable way to know the

		 * switch failed. If there really is a problem, we would expect

		 * tuning will fail and the result ends up the same.

		 */

		err = __mmc_switch_status(card, false);



		/*

		 * mmc_select_timing() assumes timing has not changed if

		 * it is a switch error.

drivers/mmc/core/mmc_ops.c

+8 −1
Original line number Diff line number Diff line
@@ -431,18 +431,25 @@ static int mmc_switch_status_error(struct mmc_host *host, u32 status) 
}



/* Caller must hold re-tuning */

int mmc_switch_status(struct mmc_card *card)

int __mmc_switch_status(struct mmc_card *card, bool crc_err_fatal)

{

	u32 status;

	int err;



	err = mmc_send_status(card, &status);

	if (!crc_err_fatal && err == -EILSEQ)

		return 0;

	if (err)

		return err;



	return mmc_switch_status_error(card->host, status);

}



int mmc_switch_status(struct mmc_card *card)

{

	return __mmc_switch_status(card, true);

}



static int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,

			bool send_status, bool retry_crc_err)

{

drivers/mmc/core/mmc_ops.h

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ int mmc_bus_test(struct mmc_card *card, u8 bus_width); 
int mmc_send_hpi_cmd(struct mmc_card *card, u32 *status);

int mmc_can_ext_csd(struct mmc_card *card);

int mmc_switch_status(struct mmc_card *card);

int __mmc_switch_status(struct mmc_card *card, bool crc_err_fatal);

int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,

		unsigned int timeout_ms, unsigned char timing,

		bool use_busy_signal, bool send_status,	bool retry_crc_err);

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