From f4c5522b0a8827f39f83f928961d87e081bfe71c Mon Sep 17 00:00:00 2001 From: Andrei Warkentin Date: Thu, 31 Mar 2011 18:40:00 -0500 Subject: [PATCH] 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 +++++++++++++++++++++++++++++++++++++++++++++--- drivers/mmc/core/mmc.c | 5 +++ include/linux/mmc/card.h | 2 ++ include/linux/mmc/mmc.h | 4 +++ 4 files changed, 88 insertions(+), 4 deletions(-) diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index 61d233a..91a6767 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: diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index 5c611a6..ae6b8fd 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -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 diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h index 557b732..c4e96fa 100644 --- a/include/linux/mmc/card.h +++ b/include/linux/mmc/card.h @@ -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; diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h index b5ec88f..390aa6e 100644 --- a/include/linux/mmc/mmc.h +++ b/include/linux/mmc/mmc.h @@ -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) -- 2.7.4