On Wed, Dec 21, 2011 at 1:09 PM, Saugata Das <saugata.das@xxxxxxxxxxxxxx> wrote:
> From: Saugata Das <saugata.das@xxxxxxxxxx>
>
> MMC-4.5 data tag feature will be used to store the file system meta-data in the
> tagged region of eMMC. This will improve the write and subsequent read transfer
> time for the meta data.
>
> Signed-off-by: Saugata Das <saugata.das@xxxxxxxxxx>
I tested this on a device which supports a data tag unit size of 8K.
Tested-by: Venkatraman S <svenkatr@xxxxxx>
Chris,
Can this go into 3.3 ?
> ---
> drivers/mmc/card/block.c | 17 +++++++++++++++--
> drivers/mmc/core/mmc.c | 14 ++++++++++++++
> include/linux/mmc/card.h | 2 ++
> include/linux/mmc/mmc.h | 3 +++
> 4 files changed, 34 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index a1cb21f..af3b6c3 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -995,6 +995,7 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
> struct mmc_blk_request *brq = &mqrq->brq;
> struct request *req = mqrq->req;
> struct mmc_blk_data *md = mq->data;
> + bool do_data_tag;
>
> /*
> * Reliable writes are used to implement Forced Unit Access and
> @@ -1071,6 +1072,16 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
> mmc_apply_rel_rw(brq, card, req);
>
> /*
> + * Data tag is used only during writing meta data to speed
> + * up write and any subsequent read of this meta data
> + */
> + do_data_tag = (card->ext_csd.data_tag_unit_size) &&
> + (req->cmd_flags & REQ_META) &&
> + (rq_data_dir(req) == WRITE) &&
> + ((brq->data.blocks * brq->data.blksz) >=
> + card->ext_csd.data_tag_unit_size) ;
> +
> + /*
> * 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,
> @@ -1091,10 +1102,12 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>
> if ((md->flags & MMC_BLK_CMD23) &&
> mmc_op_multi(brq->cmd.opcode) &&
> - (do_rel_wr || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23))) {
> + (do_rel_wr || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23) ||
> + do_data_tag)) {
> brq->sbc.opcode = MMC_SET_BLOCK_COUNT;
> brq->sbc.arg = brq->data.blocks |
> - (do_rel_wr ? (1 << 31) : 0);
> + (do_rel_wr ? (1 << 31) : 0) |
> + (do_data_tag ? (1 << 29) : 0);
> brq->sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;
> brq->mrq.sbc = &brq->sbc;
> }
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index dbf421a..244049b 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -488,6 +488,20 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
> ext_csd[EXT_CSD_CACHE_SIZE + 1] << 8 |
> ext_csd[EXT_CSD_CACHE_SIZE + 2] << 16 |
> ext_csd[EXT_CSD_CACHE_SIZE + 3] << 24;
> +
> + if (ext_csd[EXT_CSD_DATA_SECTOR_SIZE] == 1)
> + card->ext_csd.data_sector_size = 4096;
> + else
> + card->ext_csd.data_sector_size = 512;
> +
> + if ((ext_csd[EXT_CSD_DATA_TAG_SUPPORT] & 1) &&
> + (ext_csd[EXT_CSD_TAG_UNIT_SIZE] <= 8)) {
> + card->ext_csd.data_tag_unit_size =
> + ((unsigned int) 1 << ext_csd[EXT_CSD_TAG_UNIT_SIZE]) *
> + (card->ext_csd.data_sector_size);
> + } else {
> + card->ext_csd.data_tag_unit_size = 0;
> + }
> }
>
> out:
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 415f2db..a55668d 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -71,6 +71,8 @@ struct mmc_ext_csd {
> bool hpi_en; /* HPI enablebit */
> bool hpi; /* HPI support bit */
> unsigned int hpi_cmd; /* cmd used as HPI */
> + unsigned int data_sector_size; /* 512Bytes or 4KB */
> + unsigned int data_tag_unit_size; /* DATA TAG UNIT size */
> u8 raw_partition_support; /* 160 */
> u8 raw_erased_mem_count; /* 181 */
> u8 raw_ext_csd_structure; /* 194 */
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index 0e71356..e076f7f 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -273,6 +273,7 @@ struct _mmc_csd {
> #define EXT_CSD_FLUSH_CACHE 32 /* W */
> #define EXT_CSD_CACHE_CTRL 33 /* R/W */
> #define EXT_CSD_POWER_OFF_NOTIFICATION 34 /* R/W */
> +#define EXT_CSD_DATA_SECTOR_SIZE 61 /* R */
> #define EXT_CSD_GP_SIZE_MULT 143 /* R/W */
> #define EXT_CSD_PARTITION_ATTRIBUTE 156 /* R/W */
> #define EXT_CSD_PARTITION_SUPPORT 160 /* RO */
> @@ -313,6 +314,8 @@ struct _mmc_csd {
> #define EXT_CSD_POWER_OFF_LONG_TIME 247 /* RO */
> #define EXT_CSD_GENERIC_CMD6_TIME 248 /* RO */
> #define EXT_CSD_CACHE_SIZE 249 /* RO, 4 bytes */
> +#define EXT_CSD_TAG_UNIT_SIZE 498 /* RO */
> +#define EXT_CSD_DATA_TAG_SUPPORT 499 /* RO */
> #define EXT_CSD_HPI_FEATURES 503 /* RO */
>
> /*
> --
> 1.7.4.3
>
> --
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