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Commit 794b0bcc authored by Asutosh Das's avatar Asutosh Das Committed by Matt Wagantall
Browse files

mmc: core: Add support to read command queue parameters 



eMMC cards with EXT_CSD version >= 7, optionally support command
queuing feature as defined by JEDEC eMMC5.1. Add support for probing
command queue feature for such type of cards.

Change-Id: I9454d0d6997ccbd1778a147354859467f4a9a7d3
Signed-off-by: default avatarSujit Reddy Thumma <sthumma@codeaurora.org>
Signed-off-by: default avatarAsutosh Das <asutoshd@codeaurora.org>
Signed-off-by: default avatarVenkat Gopalakrishnan <venkatg@codeaurora.org>
parent df63c9cb

drivers/mmc/core/mmc.c

+18 −0
Original line number Diff line number Diff line
@@ -647,6 +647,24 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd) 
		card->ext_csd.data_sector_size = 512;

	}



	if (card->ext_csd.rev >= 7) {

		card->ext_csd.cmdq_support = ext_csd[EXT_CSD_CMDQ_SUPPORT];

		if (card->ext_csd.cmdq_support) {

			/*

			 * Queue Depth = N + 1,

			 * see JEDEC JESD84-B51 section 7.4.19

			 */

			card->ext_csd.cmdq_depth =

				ext_csd[EXT_CSD_CMDQ_DEPTH] + 1;

			pr_info("%s: CMDQ supported: depth: %d\n",

				mmc_hostname(card->host),

				card->ext_csd.cmdq_depth);

		}

	} else {

		card->ext_csd.cmdq_support = 0;

		card->ext_csd.cmdq_depth = 0;

	}



out:

	return err;

}

include/linux/mmc/card.h

+2 −0
Original line number Diff line number Diff line
@@ -116,6 +116,8 @@ struct mmc_ext_csd { 
	u8			raw_pwr_cl_ddr_200_360;	/* 253 */

	u8			raw_bkops_status;	/* 246 */

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

	u8			cmdq_depth;		/* 307 */

	u8			cmdq_support;		/* 308 */



	unsigned int            feature_support;

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

include/linux/mmc/mmc.h

+2 −0
Original line number Diff line number Diff line
@@ -274,6 +274,8 @@ struct _mmc_csd { 
#define EXT_CSD_GENERIC_CMD6_TIME	248	/* RO */

#define EXT_CSD_CACHE_SIZE		249	/* RO, 4 bytes */

#define EXT_CSD_PWR_CL_DDR_200_360	253	/* RO */

#define EXT_CSD_CMDQ_DEPTH		307	/* RO */

#define EXT_CSD_CMDQ_SUPPORT		308	/* RO */

#define EXT_CSD_TAG_UNIT_SIZE		498	/* RO */

#define EXT_CSD_DATA_TAG_SUPPORT	499	/* RO */

#define EXT_CSD_MAX_PACKED_WRITES	500	/* RO */