RE: [PATCH RESEND v7 2/3] mmc: core: Support packed write command for eMMC4.5 device

Seungwon Jeon
2012-06-26T09:27:43Z

S, Venkatraman <svenkatr@ti.com> wrote:
> On Mon, Jun 18, 2012 at 11:13 AM, Seungwon Jeon <tgih.jun@samsung.com> wrote:
> > This patch supports packed write command of eMMC4.5 device.
> > Several 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@samsung.com>
> > ---
> >  drivers/mmc/card/block.c   |  406 +++++++++++++++++++++++++++++++++++++++++---
> >  drivers/mmc/card/queue.c   |   45 +++++-
> >  drivers/mmc/card/queue.h   |   12 ++
> >  drivers/mmc/core/mmc_ops.c |    1 +
> >  include/linux/mmc/core.h   |    4 +
> >  5 files changed, 441 insertions(+), 27 deletions(-)
> >
> > diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> > index 7e3f453..eb99e35 100644
> > --- a/drivers/mmc/card/block.c
> > +++ b/drivers/mmc/card/block.c
> > @@ -58,6 +58,12 @@ 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_WR          0x02
> > +
> >  static DEFINE_MUTEX(block_mutex);
> >
> >  /*
> > @@ -123,9 +129,21 @@ enum mmc_blk_status {
> >        MMC_BLK_NOMEDIUM,
> >  };
> >
> > +enum {
> > +       MMC_PACKED_N_IDX = -1,
> > +       MMC_PACKED_N_ZERO,
> > +       MMC_PACKED_N_SINGLE,
> > +};
> > +
> >  module_param(perdev_minors, int, 0444);
> >  MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device");
> >
> > +static inline void mmc_blk_clear_packed(struct mmc_queue_req *mqrq)
> > +{
> > +       mqrq->packed_cmd = MMC_PACKED_NONE;
> > +       mqrq->packed_num = MMC_PACKED_N_ZERO;
> > +}
> > +
> >  static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
> >  {
> >        struct mmc_blk_data *md;
> > @@ -1081,12 +1099,61 @@ 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];
> > +
> > +       mq_rq->packed_retries--;
> > +       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,
> > @@ -1241,10 +1308,197 @@ 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;
> > +
> > +       mmc_blk_clear_packed(mq->mqrq_cur);
> > +
> > +       if (!(md->flags & MMC_BLK_CMD23) ||
> > +                       !card->ext_csd.packed_event_en)
> > +               goto no_packed;
> > +
> > +       if ((rq_data_dir(cur) == WRITE) &&
> > +                       (card->host->caps2 & MMC_CAP2_PACKED_WR))
> > +               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;
> > +       }
> > +
> > +       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 += cur->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;
> > +               mq->mqrq_cur->packed_retries = reqs;
>
> ^^ This means that the number of times the packed command is retried
> is equal to the number of requests
> it packs ? How are they related ?
Retrying value is just maximum by using the number of requests which is packed.

Thanks,
Seungwon Jeon

>
> > +               return reqs;
> > +       }
> > +
> > +no_packed:
> > +       mmc_blk_clear_packed(mq->mqrq_cur);
> > +       return 0;
> > +}
> > +