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Commit 6376f69d authored by Adrian Hunter's avatar Adrian Hunter Committed by Ulf Hansson
Browse files

mmc: core: Add support for HS400 re-tuning 



HS400 re-tuning must be done in HS200 mode. Add
the ability to switch from HS400 mode to HS200
mode before re-tuning and switch back to HS400
after re-tuning.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent ed16f58d

drivers/mmc/core/core.h

+2 −0
Original line number Diff line number Diff line
@@ -88,6 +88,8 @@ void mmc_remove_card_debugfs(struct mmc_card *card); 
void mmc_init_context_info(struct mmc_host *host);



int mmc_execute_tuning(struct mmc_card *card);

int mmc_hs200_to_hs400(struct mmc_card *card);

int mmc_hs400_to_hs200(struct mmc_card *card);



#endif

drivers/mmc/core/host.c

+17 −0
Original line number Diff line number Diff line
@@ -340,6 +340,7 @@ void mmc_retune_release(struct mmc_host *host) 


int mmc_retune(struct mmc_host *host)

{

	bool return_to_hs400 = false;

	int err;



	if (host->retune_now)
@@ -354,8 +355,24 @@ int mmc_retune(struct mmc_host *host) 


	host->doing_retune = 1;



	if (host->ios.timing == MMC_TIMING_MMC_HS400) {

		err = mmc_hs400_to_hs200(host->card);

		if (err)

			goto out;



		return_to_hs400 = true;



		if (host->ops->prepare_hs400_tuning)

			host->ops->prepare_hs400_tuning(host, &host->ios);

	}



	err = mmc_execute_tuning(host->card);

	if (err)

		goto out;



	if (return_to_hs400)

		err = mmc_hs200_to_hs400(host->card);

out:

	host->doing_retune = 0;



	return err;

drivers/mmc/core/mmc.c

+88 −0
Original line number Diff line number Diff line
@@ -1092,6 +1092,94 @@ static int mmc_select_hs400(struct mmc_card *card) 
	return 0;

}



int mmc_hs200_to_hs400(struct mmc_card *card)

{

	return mmc_select_hs400(card);

}



/* Caller must hold re-tuning */

static int mmc_switch_status(struct mmc_card *card)

{

	u32 status;

	int err;



	err = mmc_send_status(card, &status);

	if (err)

		return err;



	return mmc_switch_status_error(card->host, status);

}



int mmc_hs400_to_hs200(struct mmc_card *card)

{

	struct mmc_host *host = card->host;

	bool send_status = true;

	unsigned int max_dtr;

	int err;



	if (host->caps & MMC_CAP_WAIT_WHILE_BUSY)

		send_status = false;



	/* Reduce frequency to HS */

	max_dtr = card->ext_csd.hs_max_dtr;

	mmc_set_clock(host, max_dtr);



	/* Switch HS400 to HS DDR */

	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,

			   EXT_CSD_TIMING_HS, card->ext_csd.generic_cmd6_time,

			   true, send_status, true);

	if (err)

		goto out_err;



	mmc_set_timing(host, MMC_TIMING_MMC_DDR52);



	if (!send_status) {

		err = mmc_switch_status(card);

		if (err)

			goto out_err;

	}



	/* Switch HS DDR to HS */

	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BUS_WIDTH,

			   EXT_CSD_BUS_WIDTH_8, card->ext_csd.generic_cmd6_time,

			   true, send_status, true);

	if (err)

		goto out_err;



	mmc_set_timing(host, MMC_TIMING_MMC_HS);



	if (!send_status) {

		err = mmc_switch_status(card);

		if (err)

			goto out_err;

	}



	/* Switch HS to HS200 */

	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,

			   EXT_CSD_TIMING_HS200,

			   card->ext_csd.generic_cmd6_time, true, send_status,

			   true);

	if (err)

		goto out_err;



	mmc_set_timing(host, MMC_TIMING_MMC_HS200);



	if (!send_status) {

		err = mmc_switch_status(card);

		if (err)

			goto out_err;

	}



	mmc_set_bus_speed(card);



	return 0;



out_err:

	pr_err("%s: %s failed, error %d\n", mmc_hostname(card->host),

	       __func__, err);

	return err;

}



/*

 * For device supporting HS200 mode, the following sequence

 * should be done before executing the tuning process.