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Commit b3bf9153 authored by Kyungmin Park's avatar Kyungmin Park Committed by Chris Ball
Browse files

mmc: core: new discard feature support at eMMC v4.5 



MMC v4.5 supports the DISCARD feature (CMD38).  It's different from
trim and there's no check bit.  Currently it's only supported at v4.5.

Signed-off-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: default avatarJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent d9ddd629

drivers/mmc/card/block.c

+3 −1
Original line number Diff line number Diff line
@@ -756,7 +756,9 @@ static int mmc_blk_issue_discard_rq(struct mmc_queue *mq, struct request *req) 
	from = blk_rq_pos(req);

	nr = blk_rq_sectors(req);



	if (mmc_can_trim(card))

	if (mmc_can_discard(card))

		arg = MMC_DISCARD_ARG;

	else if (mmc_can_trim(card))

		arg = MMC_TRIM_ARG;

	else

		arg = MMC_ERASE_ARG;

drivers/mmc/core/core.c

+14 −0
Original line number Diff line number Diff line
@@ -1709,10 +1709,24 @@ int mmc_can_trim(struct mmc_card *card) 
{

	if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_GB_CL_EN)

		return 1;

	if (mmc_can_discard(card))

		return 1;

	return 0;

}

EXPORT_SYMBOL(mmc_can_trim);



int mmc_can_discard(struct mmc_card *card)

{

	/*

	 * As there's no way to detect the discard support bit at v4.5

	 * use the s/w feature support filed.

	 */

	if (card->ext_csd.feature_support & MMC_DISCARD_FEATURE)

		return 1;

	return 0;

}

EXPORT_SYMBOL(mmc_can_discard);



int mmc_can_sanitize(struct mmc_card *card)

{

	if (card->ext_csd.sec_feature_support & EXT_CSD_SEC_SANITIZE)

drivers/mmc/core/mmc.c

+4 −0
Original line number Diff line number Diff line
@@ -452,6 +452,10 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd) 
		card->ext_csd.rst_n_function = ext_csd[EXT_CSD_RST_N_FUNCTION];

	}



	/* eMMC v4.5 or later */

	if (card->ext_csd.rev >= 6)

		card->ext_csd.feature_support |= MMC_DISCARD_FEATURE;



	card->ext_csd.raw_erased_mem_count = ext_csd[EXT_CSD_ERASED_MEM_CONT];

	if (ext_csd[EXT_CSD_ERASED_MEM_CONT])

		card->erased_byte = 0xFF;

include/linux/mmc/card.h

+3 −0
Original line number Diff line number Diff line
@@ -80,6 +80,9 @@ struct mmc_ext_csd { 
	u8			raw_sec_feature_support;/* 231 */

	u8			raw_trim_mult;		/* 232 */

	u8			raw_sectors[4];		/* 212 - 4 bytes */



	unsigned int            feature_support;

#define MMC_DISCARD_FEATURE	BIT(0)                  /* CMD38 feature */

};



struct sd_scr {

include/linux/mmc/core.h

+2 −0
Original line number Diff line number Diff line
@@ -146,6 +146,7 @@ extern int mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int); 
#define MMC_ERASE_ARG		0x00000000

#define MMC_SECURE_ERASE_ARG	0x80000000

#define MMC_TRIM_ARG		0x00000001

#define MMC_DISCARD_ARG		0x00000003

#define MMC_SECURE_TRIM1_ARG	0x80000001

#define MMC_SECURE_TRIM2_ARG	0x80008000
@@ -156,6 +157,7 @@ extern int mmc_erase(struct mmc_card *card, unsigned int from, unsigned int nr, 
		     unsigned int arg);

extern int mmc_can_erase(struct mmc_card *card);

extern int mmc_can_trim(struct mmc_card *card);

extern int mmc_can_discard(struct mmc_card *card);

extern int mmc_can_sanitize(struct mmc_card *card);

extern int mmc_can_secure_erase_trim(struct mmc_card *card);

extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,