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Commit 81ac2af6 authored by Shawn Lin's avatar Shawn Lin Committed by Ulf Hansson
Browse files

mmc: core: implement enhanced strobe support 



Controllers use data strobe line to latch data from devices
under hs400 mode, but not for cmd line. So since emmc 5.1, JEDEC
introduces enhanced strobe mode for latching cmd response from
emmc devices to host controllers. This new feature is optional,
so it depends both on device's cap and host's cap to decide
whether to use it or not.

Signed-off-by: default avatarShawn Lin <shawn.lin@rock-chips.com>

Reviewed-by: default avatarJaehoon Chung <jh80.chung@samsung.com>
Tested-by: default avatarDouglas Anderson <dianders@chromium.org>
Tested-by: default avatarJaehoon Chung <jh80.chung@samsung.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent ef29c0e2

drivers/mmc/core/bus.c

+2 −1
Original line number Diff line number Diff line
@@ -332,12 +332,13 @@ int mmc_add_card(struct mmc_card *card) 
			mmc_card_ddr52(card) ? "DDR " : "",

			type);

	} else {

		pr_info("%s: new %s%s%s%s%s card at address %04x\n",

		pr_info("%s: new %s%s%s%s%s%s card at address %04x\n",

			mmc_hostname(card->host),

			mmc_card_uhs(card) ? "ultra high speed " :

			(mmc_card_hs(card) ? "high speed " : ""),

			mmc_card_hs400(card) ? "HS400 " :

			(mmc_card_hs200(card) ? "HS200 " : ""),

			mmc_card_hs400es(card) ? "Enhanced strobe " : "",

			mmc_card_ddr52(card) ? "DDR " : "",

			uhs_bus_speed_mode, type, card->rca);

	}

drivers/mmc/core/core.c

+9 −0
Original line number Diff line number Diff line
@@ -1127,6 +1127,15 @@ void mmc_set_initial_state(struct mmc_host *host) 
	host->ios.bus_width = MMC_BUS_WIDTH_1;

	host->ios.timing = MMC_TIMING_LEGACY;

	host->ios.drv_type = 0;

	host->ios.enhanced_strobe = false;



	/*

	 * Make sure we are in non-enhanced strobe mode before we

	 * actually enable it in ext_csd.

	 */

	if ((host->caps2 & MMC_CAP2_HS400_ES) &&

	     host->ops->hs400_enhanced_strobe)

		host->ops->hs400_enhanced_strobe(host, &host->ios);



	mmc_set_ios(host);

}

drivers/mmc/core/mmc.c

+82 −2
Original line number Diff line number Diff line
@@ -235,6 +235,11 @@ static void mmc_select_card_type(struct mmc_card *card) 
		avail_type |= EXT_CSD_CARD_TYPE_HS400_1_2V;

	}



	if ((caps2 & MMC_CAP2_HS400_ES) &&

	    card->ext_csd.strobe_support &&

	    (avail_type & EXT_CSD_CARD_TYPE_HS400))

		avail_type |= EXT_CSD_CARD_TYPE_HS400ES;



	card->ext_csd.hs_max_dtr = hs_max_dtr;

	card->ext_csd.hs200_max_dtr = hs200_max_dtr;

	card->mmc_avail_type = avail_type;
@@ -386,6 +391,7 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd) 
			mmc_card_set_blockaddr(card);

	}



	card->ext_csd.strobe_support = ext_csd[EXT_CSD_STROBE_SUPPORT];

	card->ext_csd.raw_card_type = ext_csd[EXT_CSD_CARD_TYPE];

	mmc_select_card_type(card);
@@ -1223,6 +1229,78 @@ int mmc_hs400_to_hs200(struct mmc_card *card) 
	return err;

}



static int mmc_select_hs400es(struct mmc_card *card)

{

	struct mmc_host *host = card->host;

	int err = 0;

	u8 val;



	if (!(host->caps & MMC_CAP_8_BIT_DATA)) {

		err = -ENOTSUPP;

		goto out_err;

	}



	err = mmc_select_bus_width(card);

	if (err < 0)

		goto out_err;



	/* Switch card to HS mode */

	err = mmc_select_hs(card);

	if (err) {

		pr_err("%s: switch to high-speed failed, err:%d\n",

			mmc_hostname(host), err);

		goto out_err;

	}



	err = mmc_switch_status(card);

	if (err)

		goto out_err;



	/* Switch card to DDR with strobe bit */

	val = EXT_CSD_DDR_BUS_WIDTH_8 | EXT_CSD_BUS_WIDTH_STROBE;

	err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,

			 EXT_CSD_BUS_WIDTH,

			 val,

			 card->ext_csd.generic_cmd6_time);

	if (err) {

		pr_err("%s: switch to bus width for hs400es failed, err:%d\n",

			mmc_hostname(host), err);

		goto out_err;

	}



	/* Switch card to HS400 */

	val = EXT_CSD_TIMING_HS400 |

	      card->drive_strength << EXT_CSD_DRV_STR_SHIFT;

	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,

			   EXT_CSD_HS_TIMING, val,

			   card->ext_csd.generic_cmd6_time,

			   true, false, true);

	if (err) {

		pr_err("%s: switch to hs400es failed, err:%d\n",

			mmc_hostname(host), err);

		goto out_err;

	}



	/* Set host controller to HS400 timing and frequency */

	mmc_set_timing(host, MMC_TIMING_MMC_HS400);



	/* Controller enable enhanced strobe function */

	host->ios.enhanced_strobe = true;

	if (host->ops->hs400_enhanced_strobe)

		host->ops->hs400_enhanced_strobe(host, &host->ios);



	err = mmc_switch_status(card);

	if (err)

		goto out_err;



	return 0;



out_err:

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

	       __func__, err);

	return err;

}



static void mmc_select_driver_type(struct mmc_card *card)

{

	int card_drv_type, drive_strength, drv_type;
@@ -1310,7 +1388,7 @@ static int mmc_select_hs200(struct mmc_card *card) 
}



/*

 * Activate High Speed or HS200 mode if supported.

 * Activate High Speed, HS200 or HS400ES mode if supported.

 */

static int mmc_select_timing(struct mmc_card *card)

{
@@ -1319,7 +1397,9 @@ static int mmc_select_timing(struct mmc_card *card) 
	if (!mmc_can_ext_csd(card))

		goto bus_speed;



	if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)

	if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400ES)

		err = mmc_select_hs400es(card);

	else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)

		err = mmc_select_hs200(card);

	else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)

		err = mmc_select_hs(card);

include/linux/mmc/card.h

+1 −0
Original line number Diff line number Diff line
@@ -95,6 +95,7 @@ struct mmc_ext_csd { 
	u8			raw_partition_support;	/* 160 */

	u8			raw_rpmb_size_mult;	/* 168 */

	u8			raw_erased_mem_count;	/* 181 */

	u8			strobe_support;		/* 184 */

	u8			raw_ext_csd_structure;	/* 194 */

	u8			raw_card_type;		/* 196 */

	u8			raw_driver_strength;	/* 197 */

include/linux/mmc/host.h

+11 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 


#include <linux/mmc/core.h>

#include <linux/mmc/card.h>

#include <linux/mmc/mmc.h>

#include <linux/mmc/pm.h>



struct mmc_ios {
@@ -77,6 +78,8 @@ struct mmc_ios { 
#define MMC_SET_DRIVER_TYPE_A	1

#define MMC_SET_DRIVER_TYPE_C	2

#define MMC_SET_DRIVER_TYPE_D	3



	bool enhanced_strobe;			/* hs400es selection */

};



struct mmc_host_ops {
@@ -143,6 +146,9 @@ struct mmc_host_ops { 


	/* Prepare HS400 target operating frequency depending host driver */

	int	(*prepare_hs400_tuning)(struct mmc_host *host, struct mmc_ios *ios);

	/* Prepare enhanced strobe depending host driver */

	void	(*hs400_enhanced_strobe)(struct mmc_host *host,

					 struct mmc_ios *ios);

	int	(*select_drive_strength)(struct mmc_card *card,

					 unsigned int max_dtr, int host_drv,

					 int card_drv, int *drv_type);
@@ -514,6 +520,11 @@ static inline bool mmc_card_hs400(struct mmc_card *card) 
	return card->host->ios.timing == MMC_TIMING_MMC_HS400;

}



static inline bool mmc_card_hs400es(struct mmc_card *card)

{

	return card->host->ios.enhanced_strobe;

}



void mmc_retune_timer_stop(struct mmc_host *host);



static inline void mmc_retune_needed(struct mmc_host *host)