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Commit b2499518 authored by Adrian Hunter's avatar Adrian Hunter Committed by Chris Ball
Browse files

mmc: core: add eMMC hardware reset support 



eMMC's may have a hardware reset line.  This patch provides a
host controller operation to implement hardware reset and
a function to reset and reinitialize the card.  Also, for MMC,
the reset is always performed before initialization.

The host must set the new host capability MMC_CAP_HW_RESET
to enable hardware reset.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 8e3336b1

drivers/mmc/core/core.c

+94 −0
Original line number Diff line number Diff line
@@ -1776,6 +1776,94 @@ int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen) 
}

EXPORT_SYMBOL(mmc_set_blocklen);



static void mmc_hw_reset_for_init(struct mmc_host *host)

{

	if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)

		return;

	mmc_host_clk_hold(host);

	host->ops->hw_reset(host);

	mmc_host_clk_release(host);

}



int mmc_can_reset(struct mmc_card *card)

{

	u8 rst_n_function;



	if (!mmc_card_mmc(card))

		return 0;

	rst_n_function = card->ext_csd.rst_n_function;

	if ((rst_n_function & EXT_CSD_RST_N_EN_MASK) != EXT_CSD_RST_N_ENABLED)

		return 0;

	return 1;

}

EXPORT_SYMBOL(mmc_can_reset);



static int mmc_do_hw_reset(struct mmc_host *host, int check)

{

	struct mmc_card *card = host->card;



	if (!host->bus_ops->power_restore)

		return -EOPNOTSUPP;



	if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)

		return -EOPNOTSUPP;



	if (!card)

		return -EINVAL;



	if (!mmc_can_reset(card))

		return -EOPNOTSUPP;



	mmc_host_clk_hold(host);

	mmc_set_clock(host, host->f_init);



	host->ops->hw_reset(host);



	/* If the reset has happened, then a status command will fail */

	if (check) {

		struct mmc_command cmd = {0};

		int err;



		cmd.opcode = MMC_SEND_STATUS;

		if (!mmc_host_is_spi(card->host))

			cmd.arg = card->rca << 16;

		cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;

		err = mmc_wait_for_cmd(card->host, &cmd, 0);

		if (!err) {

			mmc_host_clk_release(host);

			return -ENOSYS;

		}

	}



	host->card->state &= ~(MMC_STATE_HIGHSPEED | MMC_STATE_HIGHSPEED_DDR);

	if (mmc_host_is_spi(host)) {

		host->ios.chip_select = MMC_CS_HIGH;

		host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;

	} else {

		host->ios.chip_select = MMC_CS_DONTCARE;

		host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;

	}

	host->ios.bus_width = MMC_BUS_WIDTH_1;

	host->ios.timing = MMC_TIMING_LEGACY;

	mmc_set_ios(host);



	mmc_host_clk_release(host);



	return host->bus_ops->power_restore(host);

}



int mmc_hw_reset(struct mmc_host *host)

{

	return mmc_do_hw_reset(host, 0);

}

EXPORT_SYMBOL(mmc_hw_reset);



int mmc_hw_reset_check(struct mmc_host *host)

{

	return mmc_do_hw_reset(host, 1);

}

EXPORT_SYMBOL(mmc_hw_reset_check);



static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)

{

	host->f_init = freq;
@@ -1786,6 +1874,12 @@ static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq) 
#endif

	mmc_power_up(host);



	/*

	 * Some eMMCs (with VCCQ always on) may not be reset after power up, so

	 * do a hardware reset if possible.

	 */

	mmc_hw_reset_for_init(host);



	/*

	 * sdio_reset sends CMD52 to reset card.  Since we do not know

	 * if the card is being re-initialized, just send it.  CMD52

drivers/mmc/core/mmc.c

+3 −1
Original line number Diff line number Diff line
@@ -402,8 +402,10 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd) 
			ext_csd[EXT_CSD_TRIM_MULT];

	}



	if (card->ext_csd.rev >= 5)

	if (card->ext_csd.rev >= 5) {

		card->ext_csd.rel_param = ext_csd[EXT_CSD_WR_REL_PARAM];

		card->ext_csd.rst_n_function = ext_csd[EXT_CSD_RST_N_FUNCTION];

	}



	if (ext_csd[EXT_CSD_ERASED_MEM_CONT])

		card->erased_byte = 0xFF;

include/linux/mmc/card.h

+1 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ struct mmc_ext_csd { 
	u8			rel_sectors;

	u8			rel_param;

	u8			part_config;

	u8			rst_n_function;

	unsigned int		part_time;		/* Units: ms */

	unsigned int		sa_timeout;		/* Units: 100ns */

	unsigned int		hs_max_dtr;

include/linux/mmc/core.h

+3 −0
Original line number Diff line number Diff line
@@ -162,6 +162,9 @@ extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from, 
extern unsigned int mmc_calc_max_discard(struct mmc_card *card);



extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);

extern int mmc_hw_reset(struct mmc_host *host);

extern int mmc_hw_reset_check(struct mmc_host *host);

extern int mmc_can_reset(struct mmc_card *card);



extern void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *);

extern unsigned int mmc_align_data_size(struct mmc_card *, unsigned int);

include/linux/mmc/host.h

+2 −0
Original line number Diff line number Diff line
@@ -151,6 +151,7 @@ struct mmc_host_ops { 
	int	(*execute_tuning)(struct mmc_host *host);

	void	(*enable_preset_value)(struct mmc_host *host, bool enable);

	int	(*select_drive_strength)(unsigned int max_dtr, int host_drv, int card_drv);

	void	(*hw_reset)(struct mmc_host *host);

};



struct mmc_card;
@@ -233,6 +234,7 @@ struct mmc_host { 
#define MMC_CAP_MAX_CURRENT_600	(1 << 28)	/* Host max current limit is 600mA */

#define MMC_CAP_MAX_CURRENT_800	(1 << 29)	/* Host max current limit is 800mA */

#define MMC_CAP_CMD23		(1 << 30)	/* CMD23 supported. */

#define MMC_CAP_HW_RESET	(1 << 31)	/* Hardware reset */



	mmc_pm_flag_t		pm_caps;	/* supported pm features */