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

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

Signed-off-by: Andrei Warkentin <andreiw@motorola.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Andrei Warkentin 2011-05-23 15:06:36 -05:00 committed by Chris Ball
parent c59de92879
commit d0c97cfb81
5 changed files with 93 additions and 29 deletions
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108
drivers/mmc/card/block.c
View File

@ -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,
struct mmc_card *card,
struct request *req)
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
};

1
include/linux/mmc/card.h
View File

@ -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 */

1
include/linux/mmc/core.h
View File

@ -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;

6
include/linux/mmc/host.h
View File

@ -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

6
include/linux/mmc/mmc.h
View File

@ -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:
*