From f4c5522b0a8827f39f83f928961d87e081bfe71c Mon Sep 17 00:00:00 2001 From: Andrei Warkentin Date: Thu, 31 Mar 2011 18:40:00 -0500 Subject: 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 Reviewed-by: Arnd Bergmann Signed-off-by: Chris Ball --- drivers/mmc/card/block.c | 81 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 77 insertions(+), 4 deletions(-) (limited to 'drivers/mmc/card/block.c') diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index 61d233a7c118..91a676773608 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -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: -- cgit v1.2.3