mmc: core: Support zeroout using TRIM for eMMC

If an eMMC card supports TRIM and indicates that it erases to zeros, we can
use it to support hardware offloading of REQ_OP_WRITE_ZEROES, so let's add
support for this.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Reviewed-by: Avri Altman <Avri.Altman@wdc.com>
Link: https://lore.kernel.org/r/20220429152118.3617303-1-vincent.whitchurch@axis.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 9def975..1259ca2 100644 (file)
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -126,6 +126,7 @@ struct mmc_blk_data {
 #define MMC_BLK_DISCARD                BIT(2)
 #define MMC_BLK_SECDISCARD     BIT(3)
 #define MMC_BLK_CQE_RECOVERY   BIT(4)
+#define MMC_BLK_TRIM           BIT(5)
 
        /*
         * Only set in main mmc_blk_data associated
@@ -1092,12 +1093,13 @@ static void mmc_blk_issue_drv_op(struct mmc_queue *mq, struct request *req)
        blk_mq_end_request(req, ret ? BLK_STS_IOERR : BLK_STS_OK);
 }
 
-static void mmc_blk_issue_discard_rq(struct mmc_queue *mq, struct request *req)
+static void mmc_blk_issue_erase_rq(struct mmc_queue *mq, struct request *req,
+                                  int type, unsigned int erase_arg)
 {
        struct mmc_blk_data *md = mq->blkdata;
        struct mmc_card *card = md->queue.card;
        unsigned int from, nr;
-       int err = 0, type = MMC_BLK_DISCARD;
+       int err = 0;
        blk_status_t status = BLK_STS_OK;
 
        if (!mmc_can_erase(card)) {
@@ -1113,13 +1115,13 @@ static void mmc_blk_issue_discard_rq(struct mmc_queue *mq, struct request *req)
                if (card->quirks & MMC_QUIRK_INAND_CMD38) {
                        err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
                                         INAND_CMD38_ARG_EXT_CSD,
-                                        card->erase_arg == MMC_TRIM_ARG ?
+                                        erase_arg == MMC_TRIM_ARG ?
                                         INAND_CMD38_ARG_TRIM :
                                         INAND_CMD38_ARG_ERASE,
                                         card->ext_csd.generic_cmd6_time);
                }
                if (!err)
-                       err = mmc_erase(card, from, nr, card->erase_arg);
+                       err = mmc_erase(card, from, nr, erase_arg);
        } while (err == -EIO && !mmc_blk_reset(md, card->host, type));
        if (err)
                status = BLK_STS_IOERR;
@@ -1129,6 +1131,19 @@ fail:
        blk_mq_end_request(req, status);
 }
 
+static void mmc_blk_issue_trim_rq(struct mmc_queue *mq, struct request *req)
+{
+       mmc_blk_issue_erase_rq(mq, req, MMC_BLK_TRIM, MMC_TRIM_ARG);
+}
+
+static void mmc_blk_issue_discard_rq(struct mmc_queue *mq, struct request *req)
+{
+       struct mmc_blk_data *md = mq->blkdata;
+       struct mmc_card *card = md->queue.card;
+
+       mmc_blk_issue_erase_rq(mq, req, MMC_BLK_DISCARD, card->erase_arg);
+}
+
 static void mmc_blk_issue_secdiscard_rq(struct mmc_queue *mq,
                                       struct request *req)
 {
@@ -2329,6 +2344,9 @@ enum mmc_issued mmc_blk_mq_issue_rq(struct mmc_queue *mq, struct request *req)
                case REQ_OP_SECURE_ERASE:
                        mmc_blk_issue_secdiscard_rq(mq, req);
                        break;
+               case REQ_OP_WRITE_ZEROES:
+                       mmc_blk_issue_trim_rq(mq, req);
+                       break;
                case REQ_OP_FLUSH:
                        mmc_blk_issue_flush(mq, req);
                        break;

diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index c69b2d9..bbe2ea8 100644 (file)
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -191,6 +191,8 @@ static void mmc_queue_setup_discard(struct request_queue *q,
                q->limits.discard_granularity = SECTOR_SIZE;
        if (mmc_can_secure_erase_trim(card))
                blk_queue_flag_set(QUEUE_FLAG_SECERASE, q);
+       if (mmc_can_trim(card) && card->erased_byte == 0)
+               blk_queue_max_write_zeroes_sectors(q, max_discard);
 }
 
 static unsigned short mmc_get_max_segments(struct mmc_host *host)