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mmc: Reliable write support. 

Allows reliable writes to be used for MMC writes. Reliable writes are used
to service write REQ_FUA/REQ_META requests. Handles both the legacy and
the enhanced reliable write support in MMC cards.

Signed-off-by: Andrei Warkentin <andreiw@motorola.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Andrei Warkentin 2011-03-31 18:40:00 -05:00 committed by Chris Ball
parent 766a6bf6e9
commit f4c5522b0a
4 changed files with 88 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

81
drivers/mmc/card/block.c
View File

@ -48,6 +48,10 @@ MODULE_ALIAS("mmc:block");
#endif
#define MODULE_PARAM_PREFIX "mmcblk."
#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);
/*
@ -331,6 +335,57 @@ out:
return err ? 0 : 1;
}
static int mmc_blk_issue_flush(struct mmc_queue *mq, struct request *req)
{
struct mmc_blk_data *md = mq->data;
/*
* No-op, only service this because we need REQ_FUA for reliable
* writes.
*/
spin_lock_irq(&md->lock);
__blk_end_request_all(req, 0);
spin_unlock_irq(&md->lock);
return 1;
}
/*
* Reformat current write as a reliable write, supporting
* both legacy and the enhanced reliable write MMC cards.
* In each transfer we'll handle only as much as a single
* 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)
{
int err;
struct mmc_command set_count;
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))
brq->data.blocks = 1;
if (brq->data.blocks > card->ext_csd.rel_sectors)
brq->data.blocks = card->ext_csd.rel_sectors;
else if (brq->data.blocks < card->ext_csd.rel_sectors)
brq->data.blocks = 1;
}
memset(&set_count, 0, sizeof(struct mmc_command));
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)
{
struct mmc_blk_data *md = mq->data;
@ -338,6 +393,15 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
struct mmc_blk_request brq;
int ret = 1, disable_multi = 0;
/*
* Reliable writes are used to implement Forced Unit Access and
* REQ_META accesses, and are supported only on MMCs.
*/
bool do_rel_wr = ((req->cmd_flags & REQ_FUA) ||
(req->cmd_flags & REQ_META)) &&
(rq_data_dir(req) == WRITE) &&
REL_WRITES_SUPPORTED(card);
mmc_claim_host(card->host);
do {
@ -374,12 +438,14 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
if (disable_multi && brq.data.blocks > 1)
brq.data.blocks = 1;
if (brq.data.blocks > 1) {
if (brq.data.blocks > 1 || do_rel_wr) {
/* SPI multiblock writes terminate using a special
* token, not a STOP_TRANSMISSION request.
* token, not a STOP_TRANSMISSION request. Reliable
* writes use SET_BLOCK_COUNT and do not use a
* STOP_TRANSMISSION request either.
*/
if (!mmc_host_is_spi(card->host)
|| rq_data_dir(req) == READ)
if ((!mmc_host_is_spi(card->host) && !do_rel_wr) ||
rq_data_dir(req) == READ)
brq.mrq.stop = &brq.stop;
readcmd = MMC_READ_MULTIPLE_BLOCK;
writecmd = MMC_WRITE_MULTIPLE_BLOCK;
@ -396,6 +462,9 @@ 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;
mmc_set_data_timeout(&brq.data, card);
brq.data.sg = mq->sg;
@ -565,6 +634,8 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
return mmc_blk_issue_secdiscard_rq(mq, req);
else
return mmc_blk_issue_discard_rq(mq, req);
} else if (req->cmd_flags & REQ_FLUSH) {
return mmc_blk_issue_flush(mq, req);
} else {
return mmc_blk_issue_rw_rq(mq, req);
}
@ -622,6 +693,8 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
md->disk->queue = md->queue.queue;
md->disk->driverfs_dev = &card->dev;
set_disk_ro(md->disk, md->read_only);
if (REL_WRITES_SUPPORTED(card))
blk_queue_flush(md->queue.queue, REQ_FLUSH | REQ_FUA);
/*
* As discussed on lkml, GENHD_FL_REMOVABLE should:

5
drivers/mmc/core/mmc.c
View File

@ -300,6 +300,8 @@ static int mmc_read_ext_csd(struct mmc_card *card)
ext_csd[EXT_CSD_ERASE_TIMEOUT_MULT];
card->ext_csd.hc_erase_size =
ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE] << 10;
card->ext_csd.rel_sectors = ext_csd[EXT_CSD_REL_WR_SEC_C];
}
if (card->ext_csd.rev >= 4) {
@ -351,6 +353,9 @@ static int mmc_read_ext_csd(struct mmc_card *card)
ext_csd[EXT_CSD_TRIM_MULT];
}
if (card->ext_csd.rev >= 5)
card->ext_csd.rel_param = ext_csd[EXT_CSD_WR_REL_PARAM];
if (ext_csd[EXT_CSD_ERASED_MEM_CONT])
card->erased_byte = 0xFF;
else

2
include/linux/mmc/card.h
View File

@ -45,6 +45,8 @@ struct mmc_ext_csd {
u8 rev;
u8 erase_group_def;
u8 sec_feature_support;
u8 rel_sectors;
u8 rel_param;
u8 bootconfig;
unsigned int sa_timeout; /* Units: 100ns */
unsigned int hs_max_dtr;

4
include/linux/mmc/mmc.h
View File

@ -255,6 +255,7 @@ struct _mmc_csd {
#define EXT_CSD_PARTITION_ATTRIBUTE 156 /* R/W */
#define EXT_CSD_PARTITION_SUPPORT 160 /* RO */
#define EXT_CSD_WR_REL_PARAM 166 /* RO */
#define EXT_CSD_ERASE_GROUP_DEF 175 /* R/W */
#define EXT_CSD_BOOT_CONFIG 179 /* R/W */
#define EXT_CSD_ERASED_MEM_CONT 181 /* RO */
@ -265,6 +266,7 @@ struct _mmc_csd {
#define EXT_CSD_CARD_TYPE 196 /* RO */
#define EXT_CSD_SEC_CNT 212 /* RO, 4 bytes */
#define EXT_CSD_S_A_TIMEOUT 217 /* RO */
#define EXT_CSD_REL_WR_SEC_C 222 /* RO */
#define EXT_CSD_HC_WP_GRP_SIZE 221 /* RO */
#define EXT_CSD_ERASE_TIMEOUT_MULT 223 /* RO */
#define EXT_CSD_HC_ERASE_GRP_SIZE 224 /* RO */
@ -277,6 +279,8 @@ struct _mmc_csd {
* EXT_CSD field definitions
*/
#define EXT_CSD_WR_REL_PARAM_EN (1<<2)
#define EXT_CSD_CMD_SET_NORMAL (1<<0)
#define EXT_CSD_CMD_SET_SECURE (1<<1)
#define EXT_CSD_CMD_SET_CPSECURE (1<<2)