Re: [PATCH v3 2/2] mmc: core: Support packed command for eMMC4.5 device

From: Saugata Das
Date: Mon Jan 23 2012 - 05:04:06 EST


On 20 January 2012 09:36, Seungwon Jeon <tgih.jun@xxxxxxxxxxx> wrote:
> This patch supports packed command of eMMC4.5 device.
> Several reads(or writes) can be grouped in packed command
> and all data of the individual commands can be sent in a
> single transfer on the bus.
>
> Signed-off-by: Seungwon Jeon <tgih.jun@xxxxxxxxxxx>
> ---
>  drivers/mmc/card/block.c   |  469 +++++++++++++++++++++++++++++++++++++++++---
>  drivers/mmc/card/queue.c   |   48 +++++-
>  drivers/mmc/card/queue.h   |   13 ++
>  drivers/mmc/core/host.c    |    2 +
>  drivers/mmc/core/mmc_ops.c |    1 +
>  include/linux/mmc/core.h   |    3 +
>  include/linux/mmc/host.h   |    3 +
>  7 files changed, 512 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 176b78e..77d457e 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -59,6 +59,13 @@ MODULE_ALIAS("mmc:block");
>  #define INAND_CMD38_ARG_SECTRIM1 0x81
>  #define INAND_CMD38_ARG_SECTRIM2 0x88
>
> +#define mmc_req_rel_wr(req)    (((req->cmd_flags & REQ_FUA) || \
> +                       (req->cmd_flags & REQ_META)) && \
> +                       (rq_data_dir(req) == WRITE))
> +#define PACKED_CMD_VER         0x01
> +#define PACKED_CMD_RD          0x01
> +#define PACKED_CMD_WR          0x02
> +
>  static DEFINE_MUTEX(block_mutex);
>
>  /*
> @@ -99,6 +106,7 @@ struct mmc_blk_data {
>  #define MMC_BLK_WRITE          BIT(1)
>  #define MMC_BLK_DISCARD                BIT(2)
>  #define MMC_BLK_SECDISCARD     BIT(3)
> +#define MMC_BLK_WR_HDR         BIT(4)
>
>        /*
>         * Only set in main mmc_blk_data associated
> @@ -1028,7 +1036,8 @@ static int mmc_blk_err_check(struct mmc_card *card,
>         * kind.  If it was a write, we may have transitioned to
>         * program mode, which we have to wait for it to complete.
>         */
> -       if (!mmc_host_is_spi(card->host) && rq_data_dir(req) != READ) {
> +       if ((!mmc_host_is_spi(card->host) && rq_data_dir(req) != READ) ||
> +                       (mq_mrq->packed_cmd == MMC_PACKED_WR_HDR)) {
>                u32 status;
>                do {
>                        int err = get_card_status(card, &status, 5);
> @@ -1053,7 +1062,8 @@ static int mmc_blk_err_check(struct mmc_card *card,
>                       (unsigned)blk_rq_sectors(req),
>                       brq->cmd.resp[0], brq->stop.resp[0]);
>
> -               if (rq_data_dir(req) == READ) {
> +               if (rq_data_dir(req) == READ &&
> +                               mq_mrq->packed_cmd != MMC_PACKED_WR_HDR) {
>                        if (ecc_err)
>                                return MMC_BLK_ECC_ERR;
>                        return MMC_BLK_DATA_ERR;
> @@ -1065,12 +1075,60 @@ static int mmc_blk_err_check(struct mmc_card *card,
>        if (!brq->data.bytes_xfered)
>                return MMC_BLK_RETRY;
>
> +       if (mq_mrq->packed_cmd != MMC_PACKED_NONE) {
> +               if (unlikely(brq->data.blocks << 9 != brq->data.bytes_xfered))
> +                       return MMC_BLK_PARTIAL;
> +               else
> +                       return MMC_BLK_SUCCESS;
> +       }
> +
>        if (blk_rq_bytes(req) != brq->data.bytes_xfered)
>                return MMC_BLK_PARTIAL;
>
>        return MMC_BLK_SUCCESS;
>  }
>
> +static int mmc_blk_packed_err_check(struct mmc_card *card,
> +                            struct mmc_async_req *areq)
> +{
> +       struct mmc_queue_req *mq_rq = container_of(areq, struct mmc_queue_req,
> +                       mmc_active);
> +       struct request *req = mq_rq->req;
> +       int err, check, status;
> +       u8 ext_csd[512];
> +
> +       check = mmc_blk_err_check(card, areq);
> +       err = get_card_status(card, &status, 0);
> +       if (err) {
> +               pr_err("%s: error %d sending status command\n",
> +                               req->rq_disk->disk_name, err);
> +               return MMC_BLK_ABORT;
> +       }
> +
> +       if (status & R1_EXP_EVENT) {
> +               err = mmc_send_ext_csd(card, ext_csd);
> +               if (err) {
> +                       pr_err("%s: error %d sending ext_csd\n",
> +                                       req->rq_disk->disk_name, err);
> +                       return MMC_BLK_ABORT;
> +               }
> +
> +               if ((ext_csd[EXT_CSD_EXP_EVENTS_STATUS] &
> +                                       EXT_CSD_PACKED_FAILURE) &&
> +                               (ext_csd[EXT_CSD_PACKED_CMD_STATUS] &
> +                                EXT_CSD_PACKED_GENERIC_ERROR)) {
> +                       if (ext_csd[EXT_CSD_PACKED_CMD_STATUS] &
> +                                       EXT_CSD_PACKED_INDEXED_ERROR) {
> +                               mq_rq->packed_fail_idx =
> +                                       ext_csd[EXT_CSD_PACKED_FAILURE_INDEX] - 1;
> +                               return MMC_BLK_PARTIAL;
> +                       }
> +               }
> +       }
> +
> +       return check;
> +}
> +
>  static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>                               struct mmc_card *card,
>                               int disable_multi,
> @@ -1225,10 +1283,238 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>        mmc_queue_bounce_pre(mqrq);
>  }
>
> +static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req)
> +{
> +       struct request_queue *q = mq->queue;
> +       struct mmc_card *card = mq->card;
> +       struct request *cur = req, *next = NULL;
> +       struct mmc_blk_data *md = mq->data;
> +       bool en_rel_wr = card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN;
> +       unsigned int req_sectors = 0, phys_segments = 0;
> +       unsigned int max_blk_count, max_phys_segs;
> +       u8 put_back = 0;
> +       u8 max_packed_rw = 0;
> +       u8 reqs = 0;
> +
> +       mq->mqrq_cur->packed_num = 0;
> +
> +       if (!(md->flags & MMC_BLK_CMD23) ||
> +                       !card->ext_csd.packed_event_en)
> +               goto no_packed;
> +
> +       if (rq_data_dir(cur) == READ)
> +               max_packed_rw = card->ext_csd.max_packed_reads;
> +       else
> +               max_packed_rw = card->ext_csd.max_packed_writes;
> +
> +       if (max_packed_rw == 0)
> +               goto no_packed;
> +
> +       if (mmc_req_rel_wr(cur) &&
> +                       (md->flags & MMC_BLK_REL_WR) &&
> +                       !en_rel_wr) {
> +               goto no_packed;
> +       }

Is there any reason of not allowing reliable write on packed command ?
I think, it may get benefit from the packed command since reliable
writes are typically very small transfer (e.g. meta-data).

> +
> +       max_blk_count = min(card->host->max_blk_count,
> +                       card->host->max_req_size >> 9);
> +       if (unlikely(max_blk_count > 0xffff))
> +               max_blk_count = 0xffff;
> +
> +       max_phys_segs = queue_max_segments(q);
> +       req_sectors += blk_rq_sectors(cur);
> +       phys_segments += req->nr_phys_segments;
> +
> +       if (rq_data_dir(cur) == WRITE) {
> +               req_sectors++;
> +               phys_segments++;
> +       }
> +
> +       while (reqs < max_packed_rw - 1) {
> +               spin_lock_irq(q->queue_lock);
> +               next = blk_fetch_request(q);
> +               spin_unlock_irq(q->queue_lock);
> +               if (!next)
> +                       break;
> +
> +               if (next->cmd_flags & REQ_DISCARD ||
> +                               next->cmd_flags & REQ_FLUSH) {
> +                       put_back = 1;
> +                       break;
> +               }
> +
> +               if (rq_data_dir(cur) != rq_data_dir(next)) {
> +                       put_back = 1;
> +                       break;
> +               }
> +
> +               if (mmc_req_rel_wr(next) &&
> +                               (md->flags & MMC_BLK_REL_WR) &&
> +                               !en_rel_wr) {
> +                       put_back = 1;
> +                       break;
> +               }
> +
> +               req_sectors += blk_rq_sectors(next);
> +               if (req_sectors > max_blk_count) {
> +                       put_back = 1;
> +                       break;
> +               }
> +
> +               phys_segments +=  next->nr_phys_segments;
> +               if (phys_segments > max_phys_segs) {
> +                       put_back = 1;
> +                       break;
> +               }
> +
> +               list_add_tail(&next->queuelist, &mq->mqrq_cur->packed_list);
> +               cur = next;
> +               reqs++;
> +       }
> +
> +       if (put_back) {
> +               spin_lock_irq(q->queue_lock);
> +               blk_requeue_request(q, next);
> +               spin_unlock_irq(q->queue_lock);
> +       }
> +
> +       if (reqs > 0) {
> +               list_add(&req->queuelist, &mq->mqrq_cur->packed_list);
> +               mq->mqrq_cur->packed_num = ++reqs;
> +               return reqs;
> +       }
> +
> +no_packed:
> +       mq->mqrq_cur->packed_cmd = MMC_PACKED_NONE;
> +       mq->mqrq_cur->packed_num = 0;
> +       return 0;
> +}
> +
> +static void mmc_blk_packed_hdr_wrq_prep(struct mmc_queue_req *mqrq,
> +                              struct mmc_card *card,
> +                              struct mmc_queue *mq,
> +                              u8 reqs)
> +{
> +       struct mmc_blk_request *brq = &mqrq->brq;
> +       struct request *req = mqrq->req;
> +       struct request *prq;
> +       struct mmc_blk_data *md = mq->data;
> +       bool do_rel_wr;
> +       u32 *packed_cmd_hdr = mqrq->packed_cmd_hdr;
> +       u8 i = 1;
> +
> +       mqrq->packed_cmd = (rq_data_dir(req) == READ) ?
> +               MMC_PACKED_WR_HDR : MMC_PACKED_WRITE;
> +       mqrq->packed_blocks = 0;
> +       mqrq->packed_fail_idx = -1;
> +
> +       memset(packed_cmd_hdr, 0, sizeof(mqrq->packed_cmd_hdr));
> +       packed_cmd_hdr[0] = (reqs << 16) |
> +               (((rq_data_dir(req) == READ) ?
> +                 PACKED_CMD_RD : PACKED_CMD_WR) << 8) |
> +               PACKED_CMD_VER;
> +
> +       /*
> +        * Argument for each entry of packed group
> +        */
> +       list_for_each_entry(prq, &mqrq->packed_list, queuelist) {
> +               do_rel_wr = mmc_req_rel_wr(prq) && (md->flags & MMC_BLK_REL_WR);
> +               /* Argument of CMD23*/
> +               packed_cmd_hdr[(i * 2)] = (do_rel_wr ? MMC_CMD23_ARG_REL_WR : 0) |
> +                       blk_rq_sectors(prq);

The data tag flag is missed here. I think, we can have a common
function which sets the CMD23 flags in both
mmc_blk_packed_hdr_wrq_prep and mmc_blk_rw_rq_prep. This will be
useful when intergrating the next features (e.g. context id)

> +               /* Argument of CMD18 or CMD25 */
> +               packed_cmd_hdr[((i * 2)) + 1] = mmc_card_blockaddr(card) ?
> +                       blk_rq_pos(prq) : blk_rq_pos(prq) << 9;
> +               mqrq->packed_blocks += blk_rq_sectors(prq);
> +               i++;
> +       }
> +
> +       memset(brq, 0, sizeof(struct mmc_blk_request));
> +       brq->mrq.cmd = &brq->cmd;
> +       brq->mrq.data = &brq->data;
> +       brq->mrq.sbc = &brq->sbc;
> +       brq->mrq.stop = &brq->stop;
> +
> +       brq->sbc.opcode = MMC_SET_BLOCK_COUNT;
> +       brq->sbc.arg = MMC_CMD23_ARG_PACKED |
> +               ((rq_data_dir(req) == READ) ? 1 : mqrq->packed_blocks + 1);
> +       brq->sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;
> +
> +       brq->cmd.opcode = MMC_WRITE_MULTIPLE_BLOCK;
> +       brq->cmd.arg = blk_rq_pos(req);
> +       if (!mmc_card_blockaddr(card))
> +               brq->cmd.arg <<= 9;
> +       brq->cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> +       brq->data.blksz = 512;
> +       /*
> +        * Write separately the packd command header only for packed read.
> +        * In case of packed write, header is sent with blocks of data.
> +        */
> +       brq->data.blocks = (rq_data_dir(req) == READ) ?
> +               1 : mqrq->packed_blocks + 1;
> +       brq->data.flags |= MMC_DATA_WRITE;
> +
> +       brq->stop.opcode = MMC_STOP_TRANSMISSION;
> +       brq->stop.arg = 0;
> +       brq->stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
> +

We do not need MMC_STOP_TRANSMISSION when we use MMC_SET_BLOCK_COUNT

> +       mmc_set_data_timeout(&brq->data, card);
> +
> +       brq->data.sg = mqrq->sg;
> +       brq->data.sg_len = mmc_queue_map_sg(mq, mqrq);
> +
> +       mqrq->mmc_active.mrq = &brq->mrq;
> +       mqrq->mmc_active.err_check = mmc_blk_packed_err_check;
> +
> +       mmc_queue_bounce_pre(mqrq);
> +}
> +
> +static void mmc_blk_packed_rrq_prep(struct mmc_queue_req *mqrq,
> +                              struct mmc_card *card,
> +                              struct mmc_queue *mq)
> +{
> +       struct mmc_blk_request *brq = &mqrq->brq;
> +       struct request *req = mqrq->req;
> +
> +       mqrq->packed_cmd = MMC_PACKED_READ;
> +
> +       memset(brq, 0, sizeof(struct mmc_blk_request));
> +       brq->mrq.cmd = &brq->cmd;
> +       brq->mrq.data = &brq->data;
> +       brq->mrq.stop = &brq->stop;
> +
> +       brq->cmd.opcode = MMC_READ_MULTIPLE_BLOCK;
> +       brq->cmd.arg = blk_rq_pos(req);
> +       if (!mmc_card_blockaddr(card))
> +               brq->cmd.arg <<= 9;
> +       brq->cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
> +       brq->data.blksz = 512;
> +       brq->data.blocks = mqrq->packed_blocks;
> +       brq->data.flags |= MMC_DATA_READ;
> +
> +       brq->stop.opcode = MMC_STOP_TRANSMISSION;
> +       brq->stop.arg = 0;
> +       brq->stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
> +
> +       mmc_set_data_timeout(&brq->data, card);
> +
> +       brq->data.sg = mqrq->sg;
> +       brq->data.sg_len = mmc_queue_map_sg(mq, mqrq);
> +
> +       mqrq->mmc_active.mrq = &brq->mrq;
> +       mqrq->mmc_active.err_check = mmc_blk_packed_err_check;
> +
> +       mmc_queue_bounce_pre(mqrq);
> +}
> +
>  static int mmc_blk_cmd_err(struct mmc_blk_data *md, struct mmc_card *card,
>                           struct mmc_blk_request *brq, struct request *req,
>                           int ret)
>  {
> +       struct mmc_queue_req *mq_rq;
> +       mq_rq = container_of(brq, struct mmc_queue_req, brq);
> +
>        /*
>         * If this is an SD card and we're writing, we can first
>         * mark the known good sectors as ok.
> @@ -1247,13 +1533,65 @@ static int mmc_blk_cmd_err(struct mmc_blk_data *md, struct mmc_card *card,
>                        spin_unlock_irq(&md->lock);
>                }
>        } else {
> -               spin_lock_irq(&md->lock);
> -               ret = __blk_end_request(req, 0, brq->data.bytes_xfered);
> -               spin_unlock_irq(&md->lock);
> +               if (mq_rq->packed_cmd == MMC_PACKED_NONE) {
> +                       spin_lock_irq(&md->lock);
> +                       ret = __blk_end_request(req, 0, brq->data.bytes_xfered);
> +                       spin_unlock_irq(&md->lock);
> +               }
>        }
>        return ret;
>  }
>
> +static int mmc_blk_chk_hdr_err(struct mmc_queue *mq, int status)
> +{
> +       struct mmc_blk_data *md = mq->data;
> +       struct mmc_card *card = md->queue.card;
> +       int type = MMC_BLK_WR_HDR, err = 0;
> +
> +       switch (status) {
> +       case MMC_BLK_PARTIAL:
> +       case MMC_BLK_RETRY:
> +               err = 0;
> +               break;
> +       case MMC_BLK_CMD_ERR:
> +       case MMC_BLK_ABORT:
> +       case MMC_BLK_DATA_ERR:
> +       case MMC_BLK_ECC_ERR:
> +               err = mmc_blk_reset(md, card->host, type);
> +               if (!err)
> +                       mmc_blk_reset_success(md, type);
> +               break;
> +       }
> +
> +       return err;
> +}
> +
> +static int mmc_blk_issue_packed_rd(struct mmc_queue *mq,
> +               struct mmc_queue_req *mq_rq)
> +{
> +       struct mmc_blk_data *md = mq->data;
> +       struct mmc_card *card = md->queue.card;
> +       int status, ret = -EIO, retry = 2;
> +
> +       do {
> +               mmc_start_req(card->host, NULL, (int *) &status);
> +               if (status) {
> +                       ret = mmc_blk_chk_hdr_err(mq, status);
> +                       if (ret)
> +                               break;
> +                       mmc_blk_packed_hdr_wrq_prep(mq_rq, card, mq, mq_rq->packed_num);
> +                       mmc_start_req(card->host, &mq_rq->mmc_active, NULL);
> +               } else {
> +                       mmc_blk_packed_rrq_prep(mq_rq, card, mq);
> +                       mmc_start_req(card->host, &mq_rq->mmc_active, NULL);
> +                       ret = 0;
> +                       break;
> +               }
> +       } while (retry-- > 0);
> +
> +       return ret;
> +}
> +
>  static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
>  {
>        struct mmc_blk_data *md = mq->data;
> @@ -1262,21 +1600,32 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
>        int ret = 1, disable_multi = 0, retry = 0, type;
>        enum mmc_blk_status status;
>        struct mmc_queue_req *mq_rq;
> -       struct request *req;
> +       struct request *req, *prq;
>        struct mmc_async_req *areq;
> +       u8 reqs = 0;
>
>        if (!rqc && !mq->mqrq_prev->req)
>                return 0;
>
> +       if (rqc)
> +               reqs = mmc_blk_prep_packed_list(mq, rqc);
> +
>        do {
>                if (rqc) {
> -                       mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
> +                       if (reqs >= card->host->packed_min)
> +                               mmc_blk_packed_hdr_wrq_prep(mq->mqrq_cur, card, mq, reqs);
> +                       else
> +                               mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
>                        areq = &mq->mqrq_cur->mmc_active;
>                } else
>                        areq = NULL;
>                areq = mmc_start_req(card->host, areq, (int *) &status);
> -               if (!areq)
> -                       return 0;
> +               if (!areq) {
> +                       if (mq->mqrq_cur->packed_cmd == MMC_PACKED_WR_HDR)
> +                               goto snd_packed_rd;

How the condition, when (areq is not NULL) and
(mq->mqrq_cur->packed_cmd = MMC_PACKED_WR_HDR) handled ?

> +                       else
> +                               return 0;
> +               }
>
>                mq_rq = container_of(areq, struct mmc_queue_req, mmc_active);
>                brq = &mq_rq->brq;
> @@ -1291,10 +1640,38 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
>                         * A block was successfully transferred.
>                         */
>                        mmc_blk_reset_success(md, type);
> -                       spin_lock_irq(&md->lock);
> -                       ret = __blk_end_request(req, 0,
> +
> +                       if (mq_rq->packed_cmd != MMC_PACKED_NONE) {
> +                               int idx = mq_rq->packed_fail_idx, i = 0;
> +                               while (!list_empty(&mq_rq->packed_list)) {
> +                                       prq = list_entry_rq(mq_rq->packed_list.next);
> +                                       list_del_init(&prq->queuelist);
> +                                       if (idx == i) {

I think, in case of no error (packed_fail_idx=0) and when (i=0), this
above "if" condition will satisfy and subsequently wrongly retry.

> +                                               /* retry from error index */
> +                                               mq_rq->packed_num -= idx;
> +                                               if (mq_rq->packed_num == 1) {
> +                                                       mq_rq->packed_cmd = MMC_PACKED_NONE;
> +                                                       mq_rq->packed_num = 0;
> +                                               }
> +                                               mq_rq->req = prq;
> +                                               ret = 1;
> +                                               break;
> +                                       }
> +                                       spin_lock_irq(&md->lock);
> +                                       ret = __blk_end_request(prq, 0, blk_rq_bytes(prq));
> +                                       spin_unlock_irq(&md->lock);
> +                                       i++;
> +                               }
> +                               if (idx == -1)
> +                                       mq_rq->packed_num = 0;
> +                               break;
> +                       } else {
> +                               spin_lock_irq(&md->lock);
> +                               ret = __blk_end_request(req, 0,
>                                                brq->data.bytes_xfered);
> -                       spin_unlock_irq(&md->lock);
> +                               spin_unlock_irq(&md->lock);
> +                       }
> +
>                        /*
>                         * If the blk_end_request function returns non-zero even
>                         * though all data has been transferred and no errors
> @@ -1329,6 +1706,8 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
>                                break;
>                        if (err == -ENODEV)
>                                goto cmd_abort;
> +                       if (mq_rq->packed_cmd != MMC_PACKED_NONE)
> +                               break;
>                        /* Fall through */
>                }
>                case MMC_BLK_ECC_ERR:
> @@ -1356,27 +1735,69 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
>                }
>
>                if (ret) {
> -                       /*
> -                        * In case of a incomplete request
> -                        * prepare it again and resend.
> -                        */
> -                       mmc_blk_rw_rq_prep(mq_rq, card, disable_multi, mq);
> -                       mmc_start_req(card->host, &mq_rq->mmc_active, NULL);
> +                       if (mq_rq->packed_cmd == MMC_PACKED_NONE) {
> +                               /*
> +                                * In case of a incomplete request
> +                                * prepare it again and resend.
> +                                */
> +                               mmc_blk_rw_rq_prep(mq_rq, card, disable_multi, mq);
> +                               mmc_start_req(card->host, &mq_rq->mmc_active, NULL);
> +                       } else {
> +                               mmc_blk_packed_hdr_wrq_prep(mq_rq, card, mq, mq_rq->packed_num);
> +                               mmc_start_req(card->host, &mq_rq->mmc_active, NULL);
> +                               if (mq_rq->packed_cmd == MMC_PACKED_WR_HDR) {
> +                                       if (mmc_blk_issue_packed_rd(mq, mq_rq))
> +                                               goto cmd_abort;
> +                               }
> +                       }
>                }
>        } while (ret);
>
> +snd_packed_rd:
> +       if (mq->mqrq_cur->packed_cmd == MMC_PACKED_WR_HDR) {
> +               if (mmc_blk_issue_packed_rd(mq, mq->mqrq_cur))
> +                       goto start_new_req;
> +       }
>        return 1;
>
>  cmd_abort:
> -       spin_lock_irq(&md->lock);
> -       if (mmc_card_removed(card))
> -               req->cmd_flags |= REQ_QUIET;
> -       while (ret)
> -               ret = __blk_end_request(req, -EIO, blk_rq_cur_bytes(req));
> -       spin_unlock_irq(&md->lock);
> +       if (mq_rq->packed_cmd == MMC_PACKED_NONE) {
> +               spin_lock_irq(&md->lock);
> +               if (mmc_card_removed(card))
> +                       req->cmd_flags |= REQ_QUIET;
> +               while (ret)
> +                       ret = __blk_end_request(req, -EIO, blk_rq_cur_bytes(req));
> +               spin_unlock_irq(&md->lock);
> +       } else {
> +               while (!list_empty(&mq_rq->packed_list)) {
> +                       prq = list_entry_rq(mq_rq->packed_list.next);
> +                       list_del_init(&prq->queuelist);
> +                       spin_lock_irq(&md->lock);
> +                       __blk_end_request(prq, -EIO, blk_rq_bytes(prq));
> +                       spin_unlock_irq(&md->lock);
> +               }
> +       }
>
>  start_new_req:
>        if (rqc) {
> +               /*
> +                * If current request is packed, it need to put back.
> +                */
> +               if (mq->mqrq_cur->packed_cmd != MMC_PACKED_NONE) {
> +                       while (!list_empty(&mq->mqrq_cur->packed_list)) {
> +                               prq = list_entry_rq(mq->mqrq_cur->packed_list.prev);
> +                               if (prq->queuelist.prev != &mq->mqrq_cur->packed_list) {
> +                                       list_del_init(&prq->queuelist);
> +                                       spin_lock_irq(mq->queue->queue_lock);
> +                                       blk_requeue_request(mq->queue, prq);
> +                                       spin_unlock_irq(mq->queue->queue_lock);
> +                               } else {
> +                                       list_del_init(&prq->queuelist);
> +                               }
> +                       }
> +                       mq->mqrq_cur->packed_cmd = MMC_PACKED_NONE;
> +                       mq->mqrq_cur->packed_num = 0;
> +               }
>                mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
>                mmc_start_req(card->host, &mq->mqrq_cur->mmc_active, NULL);
>        }
> diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
> index 2517547..af7aee5 100644
> --- a/drivers/mmc/card/queue.c
> +++ b/drivers/mmc/card/queue.c
> @@ -177,6 +177,8 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
>
>        memset(&mq->mqrq_cur, 0, sizeof(mq->mqrq_cur));
>        memset(&mq->mqrq_prev, 0, sizeof(mq->mqrq_prev));
> +       INIT_LIST_HEAD(&mqrq_cur->packed_list);
> +       INIT_LIST_HEAD(&mqrq_prev->packed_list);
>        mq->mqrq_cur = mqrq_cur;
>        mq->mqrq_prev = mqrq_prev;
>        mq->queue->queuedata = mq;
> @@ -377,6 +379,39 @@ void mmc_queue_resume(struct mmc_queue *mq)
>        }
>  }
>
> +static unsigned int mmc_queue_packed_map_sg(struct mmc_queue *mq,
> +                               struct mmc_queue_req *mqrq,
> +                               struct scatterlist *sg)
> +{
> +       struct scatterlist *__sg;
> +       unsigned int sg_len = 0;
> +       struct request *req;
> +       enum mmc_packed_cmd cmd;
> +
> +       cmd = mqrq->packed_cmd;
> +
> +       if (cmd == MMC_PACKED_WR_HDR || cmd == MMC_PACKED_WRITE) {

Why we do not need to handle MMC_PACKED_READ case ?

> +               __sg = sg;
> +               sg_set_buf(__sg, mqrq->packed_cmd_hdr,
> +                               sizeof(mqrq->packed_cmd_hdr));
> +               sg_len++;
> +               if (cmd == MMC_PACKED_WR_HDR) {
> +                       sg_mark_end(__sg);
> +                       return sg_len;
> +               }
> +               __sg->page_link &= ~0x02;
> +       }
> +
> +       __sg = sg + sg_len;
> +       list_for_each_entry(req, &mqrq->packed_list, queuelist) {
> +               sg_len += blk_rq_map_sg(mq->queue, req, __sg);
> +               __sg = sg + (sg_len - 1);
> +               (__sg++)->page_link &= ~0x02;
> +       }
> +       sg_mark_end(sg + (sg_len - 1));
> +       return sg_len;
> +}
> +
>  /*
>  * Prepare the sg list(s) to be handed of to the host driver
>  */
> @@ -387,12 +422,19 @@ unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
>        struct scatterlist *sg;
>        int i;
>
> -       if (!mqrq->bounce_buf)
> -               return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
> +       if (!mqrq->bounce_buf) {
> +               if (!list_empty(&mqrq->packed_list))
> +                       return mmc_queue_packed_map_sg(mq, mqrq, mqrq->sg);
> +               else
> +                       return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
> +       }
>
>        BUG_ON(!mqrq->bounce_sg);
>
> -       sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
> +       if (!list_empty(&mqrq->packed_list))
> +               sg_len = mmc_queue_packed_map_sg(mq, mqrq, mqrq->bounce_sg);
> +       else
> +               sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
>
>        mqrq->bounce_sg_len = sg_len;
>
> diff --git a/drivers/mmc/card/queue.h b/drivers/mmc/card/queue.h
> index d2a1eb4..be58b3c 100644
> --- a/drivers/mmc/card/queue.h
> +++ b/drivers/mmc/card/queue.h
> @@ -12,6 +12,13 @@ struct mmc_blk_request {
>        struct mmc_data         data;
>  };
>
> +enum mmc_packed_cmd {
> +       MMC_PACKED_NONE = 0,
> +       MMC_PACKED_WR_HDR,
> +       MMC_PACKED_WRITE,
> +       MMC_PACKED_READ,
> +};
> +
>  struct mmc_queue_req {
>        struct request          *req;
>        struct mmc_blk_request  brq;
> @@ -20,6 +27,12 @@ struct mmc_queue_req {
>        struct scatterlist      *bounce_sg;
>        unsigned int            bounce_sg_len;
>        struct mmc_async_req    mmc_active;
> +       struct list_head        packed_list;
> +       u32                     packed_cmd_hdr[128];
> +       unsigned int            packed_blocks;
> +       enum mmc_packed_cmd     packed_cmd;
> +       int             packed_fail_idx;
> +       u8              packed_num;
>  };
>
>  struct mmc_queue {
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 30055f2..10350ce 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -346,6 +346,8 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
>        host->max_blk_size = 512;
>        host->max_blk_count = PAGE_CACHE_SIZE / 512;
>
> +       host->packed_min = 2;
> +
>        return host;
>
>  free:
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index 4d41fa9..1e17bd7 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -335,6 +335,7 @@ int mmc_send_ext_csd(struct mmc_card *card, u8 *ext_csd)
>        return mmc_send_cxd_data(card, card->host, MMC_SEND_EXT_CSD,
>                        ext_csd, 512);
>  }
> +EXPORT_SYMBOL_GPL(mmc_send_ext_csd);
>
>  int mmc_spi_read_ocr(struct mmc_host *host, int highcap, u32 *ocrp)
>  {
> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
> index 87a976c..07a4149 100644
> --- a/include/linux/mmc/core.h
> +++ b/include/linux/mmc/core.h
> @@ -18,6 +18,8 @@ struct mmc_request;
>  struct mmc_command {
>        u32                     opcode;
>        u32                     arg;
> +#define MMC_CMD23_ARG_REL_WR   (1 << 31)
> +#define MMC_CMD23_ARG_PACKED   ((0 << 31) | (1 << 30))
>        u32                     resp[4];
>        unsigned int            flags;          /* expected response type */
>  #define MMC_RSP_PRESENT        (1 << 0)
> @@ -143,6 +145,7 @@ extern int mmc_app_cmd(struct mmc_host *, struct mmc_card *);
>  extern int mmc_wait_for_app_cmd(struct mmc_host *, struct mmc_card *,
>        struct mmc_command *, int);
>  extern int mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int);
> +extern int mmc_send_ext_csd(struct mmc_card *card, u8 *ext_csd);
>
>  #define MMC_ERASE_ARG          0x00000000
>  #define MMC_SECURE_ERASE_ARG   0x80000000
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index e22f541..8984259 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -286,6 +286,9 @@ struct mmc_host {
>        unsigned int            max_blk_count;  /* maximum number of blocks in one req */
>        unsigned int            max_discard_to; /* max. discard timeout in ms */
>
> +       u8                      packed_min;     /* minimum number of packed entries */
> +
> +
>        /* private data */
>        spinlock_t              lock;           /* lock for claim and bus ops */
>
> --
> 1.7.0.4
>
>
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