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Commit d0c97cfb authored by Andrei Warkentin's avatar Andrei Warkentin Committed by Chris Ball
Browse files

mmc: core: Use CMD23 for multiblock transfers when we can. 



CMD23-prefixed instead of open-ended multiblock transfers
have a performance advantage on some MMC cards.

Signed-off-by: default avatarAndrei Warkentin <andreiw@motorola.com>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent c59de928

drivers/mmc/card/block.c

+79 −29
Original line number Diff line number Diff line
@@ -59,10 +59,6 @@ MODULE_ALIAS("mmc:block"); 
#define INAND_CMD38_ARG_SECTRIM1 0x81

#define INAND_CMD38_ARG_SECTRIM2 0x88



#define REL_WRITES_SUPPORTED(card) (mmc_card_mmc((card)) &&	\

    (((card)->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN) ||	\

     ((card)->ext_csd.rel_sectors)))



static DEFINE_MUTEX(block_mutex);



/*
@@ -90,6 +86,10 @@ struct mmc_blk_data { 
	struct mmc_queue queue;

	struct list_head part;



	unsigned int	flags;

#define MMC_BLK_CMD23	(1 << 0)	/* Can do SET_BLOCK_COUNT for multiblock */

#define MMC_BLK_REL_WR	(1 << 1)	/* MMC Reliable write support */



	unsigned int	usage;

	unsigned int	read_only;

	unsigned int	part_type;
@@ -429,6 +429,7 @@ static const struct block_device_operations mmc_bdops = { 


struct mmc_blk_request {

	struct mmc_request	mrq;

	struct mmc_command	sbc;

	struct mmc_command	cmd;

	struct mmc_command	stop;

	struct mmc_data		data;
@@ -652,13 +653,10 @@ static int mmc_blk_issue_flush(struct mmc_queue *mq, struct request *req) 
 * reliable write can handle, thus finish the request in

 * partial completions.

 */

static inline int mmc_apply_rel_rw(struct mmc_blk_request *brq,

static inline void mmc_apply_rel_rw(struct mmc_blk_request *brq,

				    struct mmc_card *card,

				    struct request *req)

{

	int err;

	struct mmc_command set_count = {0};



	if (!(card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN)) {

		/* Legacy mode imposes restrictions on transfers. */

		if (!IS_ALIGNED(brq->cmd.arg, card->ext_csd.rel_sectors))
@@ -669,15 +667,6 @@ static inline int mmc_apply_rel_rw(struct mmc_blk_request *brq, 
		else if (brq->data.blocks < card->ext_csd.rel_sectors)

			brq->data.blocks = 1;

	}



	set_count.opcode = MMC_SET_BLOCK_COUNT;

	set_count.arg = brq->data.blocks | (1 << 31);

	set_count.flags = MMC_RSP_R1 | MMC_CMD_AC;

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

	if (err)

		printk(KERN_ERR "%s: error %d SET_BLOCK_COUNT\n",

		       req->rq_disk->disk_name, err);

	return err;

}



static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
@@ -694,7 +683,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) 
	bool do_rel_wr = ((req->cmd_flags & REQ_FUA) ||

			  (req->cmd_flags & REQ_META)) &&

		(rq_data_dir(req) == WRITE) &&

		REL_WRITES_SUPPORTED(card);

		(md->flags & MMC_BLK_REL_WR);



	do {

		struct mmc_command cmd = {0};
@@ -732,11 +721,9 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) 


		if (brq.data.blocks > 1 || do_rel_wr) {

			/* SPI multiblock writes terminate using a special

			 * token, not a STOP_TRANSMISSION request. Reliable

			 * writes use SET_BLOCK_COUNT and do not use a

			 * STOP_TRANSMISSION request either.

			 * token, not a STOP_TRANSMISSION request.

			 */

			if ((!mmc_host_is_spi(card->host) && !do_rel_wr) ||

			if (!mmc_host_is_spi(card->host) ||

			    rq_data_dir(req) == READ)

				brq.mrq.stop = &brq.stop;

			readcmd = MMC_READ_MULTIPLE_BLOCK;
@@ -754,8 +741,37 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) 
			brq.data.flags |= MMC_DATA_WRITE;

		}



		if (do_rel_wr && mmc_apply_rel_rw(&brq, card, req))

			goto cmd_err;

		if (do_rel_wr)

			mmc_apply_rel_rw(&brq, card, req);



		/*

		 * Pre-defined multi-block transfers are preferable to

		 * open ended-ones (and necessary for reliable writes).

		 * However, it is not sufficient to just send CMD23,

		 * and avoid the final CMD12, as on an error condition

		 * CMD12 (stop) needs to be sent anyway. This, coupled

		 * with Auto-CMD23 enhancements provided by some

		 * hosts, means that the complexity of dealing

		 * with this is best left to the host. If CMD23 is

		 * supported by card and host, we'll fill sbc in and let

		 * the host deal with handling it correctly. This means

		 * that for hosts that don't expose MMC_CAP_CMD23, no

		 * change of behavior will be observed.

		 *

		 * N.B: Some MMC cards experience perf degradation.

		 * We'll avoid using CMD23-bounded multiblock writes for

		 * these, while retaining features like reliable writes.

		 */



		if ((md->flags & MMC_BLK_CMD23) &&

		    mmc_op_multi(brq.cmd.opcode) &&

		    (do_rel_wr || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23))) {

			brq.sbc.opcode = MMC_SET_BLOCK_COUNT;

			brq.sbc.arg = brq.data.blocks |

				(do_rel_wr ? (1 << 31) : 0);

			brq.sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;

			brq.mrq.sbc = &brq.sbc;

		}



		mmc_set_data_timeout(&brq.data, card);
@@ -792,7 +808,8 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) 
		 * until later as we need to wait for the card to leave

		 * programming mode even when things go wrong.

		 */

		if (brq.cmd.error || brq.data.error || brq.stop.error) {

		if (brq.sbc.error || brq.cmd.error ||

		    brq.data.error || brq.stop.error) {

			if (brq.data.blocks > 1 && rq_data_dir(req) == READ) {

				/* Redo read one sector at a time */

				printk(KERN_WARNING "%s: retrying using single "
@@ -803,6 +820,13 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) 
			status = get_card_status(card, req);

		}



		if (brq.sbc.error) {

			printk(KERN_ERR "%s: error %d sending SET_BLOCK_COUNT "

			       "command, response %#x, card status %#x\n",

			       req->rq_disk->disk_name, brq.sbc.error,

			       brq.sbc.resp[0], status);

		}



		if (brq.cmd.error) {

			printk(KERN_ERR "%s: error %d sending read/write "

			       "command, response %#x, card status %#x\n",
@@ -1014,8 +1038,6 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card, 
	md->disk->queue = md->queue.queue;

	md->disk->driverfs_dev = parent;

	set_disk_ro(md->disk, md->read_only || default_ro);

	if (REL_WRITES_SUPPORTED(card))

		blk_queue_flush(md->queue.queue, REQ_FLUSH | REQ_FUA);



	/*

	 * As discussed on lkml, GENHD_FL_REMOVABLE should:
@@ -1034,6 +1056,19 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card, 


	blk_queue_logical_block_size(md->queue.queue, 512);

	set_capacity(md->disk, size);



	if (mmc_host_cmd23(card->host) &&

	    mmc_card_mmc(card))

		md->flags |= MMC_BLK_CMD23;



	if (mmc_card_mmc(card) &&

	    md->flags & MMC_BLK_CMD23 &&

	    ((card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN) ||

	     card->ext_csd.rel_sectors)) {

		md->flags |= MMC_BLK_REL_WR;

		blk_queue_flush(md->queue.queue, REQ_FLUSH | REQ_FUA);

	}



	return md;



 err_putdisk:
@@ -1189,6 +1224,21 @@ static const struct mmc_fixup blk_fixups[] = 
	MMC_FIXUP("SEM08G", 0x2, 0x100, add_quirk, MMC_QUIRK_INAND_CMD38),

	MMC_FIXUP("SEM16G", 0x2, 0x100, add_quirk, MMC_QUIRK_INAND_CMD38),

	MMC_FIXUP("SEM32G", 0x2, 0x100, add_quirk, MMC_QUIRK_INAND_CMD38),



	/*

	 * Some MMC cards experience performance degradation with CMD23

	 * instead of CMD12-bounded multiblock transfers. For now we'll

	 * black list what's bad...

	 * - Certain Toshiba cards.

	 *

	 * N.B. This doesn't affect SD cards.

	 */

	MMC_FIXUP("MMC08G", 0x11, CID_OEMID_ANY, add_quirk_mmc,

		  MMC_QUIRK_BLK_NO_CMD23),

	MMC_FIXUP("MMC16G", 0x11, CID_OEMID_ANY, add_quirk_mmc,

		  MMC_QUIRK_BLK_NO_CMD23),

	MMC_FIXUP("MMC32G", 0x11, CID_OEMID_ANY, add_quirk_mmc,

		  MMC_QUIRK_BLK_NO_CMD23),

	END_FIXUP

};

include/linux/mmc/card.h

+1 −0
Original line number Diff line number Diff line
@@ -171,6 +171,7 @@ struct mmc_card { 
#define MMC_QUIRK_NONSTD_FUNC_IF (1<<4)		/* SDIO card has nonstd function interfaces */

#define MMC_QUIRK_DISABLE_CD	(1<<5)		/* disconnect CD/DAT[3] resistor */

#define MMC_QUIRK_INAND_CMD38	(1<<6)		/* iNAND devices have broken CMD38 */

#define MMC_QUIRK_BLK_NO_CMD23	(1<<7)		/* Avoid CMD23 for regular multiblock */



	unsigned int		erase_size;	/* erase size in sectors */

 	unsigned int		erase_shift;	/* if erase unit is power 2 */

include/linux/mmc/core.h

+1 −0
Original line number Diff line number Diff line
@@ -120,6 +120,7 @@ struct mmc_data { 
};



struct mmc_request {

	struct mmc_command	*sbc;		/* SET_BLOCK_COUNT for multiblock */

	struct mmc_command	*cmd;

	struct mmc_data		*data;

	struct mmc_command	*stop;

include/linux/mmc/host.h

+6 −0
Original line number Diff line number Diff line
@@ -210,6 +210,7 @@ struct mmc_host { 
#define MMC_CAP_MAX_CURRENT_400	(1 << 27)	/* Host max current limit is 400mA */

#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. */



	mmc_pm_flag_t		pm_caps;	/* supported pm features */
@@ -366,5 +367,10 @@ static inline int mmc_card_wake_sdio_irq(struct mmc_host *host) 
{

	return host->pm_flags & MMC_PM_WAKE_SDIO_IRQ;

}



static inline int mmc_host_cmd23(struct mmc_host *host)

{

	return host->caps & MMC_CAP_CMD23;

}

#endif

include/linux/mmc/mmc.h

+6 −0
Original line number Diff line number Diff line
@@ -83,6 +83,12 @@ 
#define MMC_APP_CMD              55   /* ac   [31:16] RCA        R1  */

#define MMC_GEN_CMD              56   /* adtc [0] RD/WR          R1  */



static inline bool mmc_op_multi(u32 opcode)

{

	return opcode == MMC_WRITE_MULTIPLE_BLOCK ||

	       opcode == MMC_READ_MULTIPLE_BLOCK;

}



/*

 * MMC_SWITCH argument format:

 *