RE: [PATCH] mmc: core: Add packed command for eMMC4.5 device

Seungwon Jeon
2011-11-17T09:20:55Z

Sahitya Tummala wrote:
> Hi,
>
> On 10/27/2011 4:24 PM, Seungwon Jeon wrote:
> >
> > +static int mmc_blk_packed_err_check(struct mmc_card *card,
> > + struct mmc_async_req *areq)
> > +{
> > + struct mmc_queue_req *mq_mrq = container_of(areq, struct mmc_queue_req,
> > + mmc_active);
> > + int err, check, status;
> > + u8 ext_csd[512];
> > +
> > + check = mmc_blk_err_check(card, areq);
> > +
> > + if (check == MMC_BLK_SUCCESS)
> > + return check;
> > +
> > + if (check == MMC_BLK_PARTIAL) {
> > + err = get_card_status(card,&status, 0);
> > + if (err)
> > + return MMC_BLK_ABORT;
> > +
> > + if (status& R1_EXP_EVENT) {
> > + err = mmc_send_ext_csd(card, ext_csd);
> > + if (err)
> > + return MMC_BLK_ABORT;
> > +
> > + if ((ext_csd[EXT_CSD_EXP_EVENTS_STATUS + 0]&
> > + 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) {
> > + /* Make be 0-based */
> > + mq_mrq->packed_fail_idx =
> > + ext_csd[EXT_CSD_PACKED_FAILURE_INDEX] - 1;
> > + return MMC_BLK_PARTIAL;
> > + } else {
> > + return MMC_BLK_RETRY;
> > + }
> > + }
> > + } else {
> > + return MMC_BLK_RETRY;
> > + }
> > + }
> > +
> > + if (check != MMC_BLK_ABORT)
> > + return MMC_BLK_RETRY;
> > + else
> > + return MMC_BLK_ABORT;
>
> The current code does not return other errors (MMC_BLK_CMD_ERR,
> MMC_BLK_ECC_ERR and MMC_BLK_DATA_ERR) returned by mmc_blk_err_check().
> Why not return check here?
Currently retry is taken in case of other errors.
But some case needs to be split.
>
> > +}
> > +
> > static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
> > struct mmc_card *card,
> > int disable_multi,
> > @@ -1126,6 +1187,207 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
> > mmc_queue_bounce_pre(mqrq);
> > }
> >
> > +static u8 mmc_blk_chk_packable(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 max_packed_rw = 0;
> > + u8 reqs = 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;
> > + }
> > +
> > + max_blk_count = min(card->host->max_blk_count,
> > + card->host->max_req_size>> 9);
> > + 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) {
>
> What if the number of requests exceeds the packed header size defined?
Currently not considered.
That case is maximum r/w depth from eMMC device is wrong, right?
It may not happen in practice. But the limit may need to restricted.
>
> > + next = blk_fetch_request(q);
> > + if (!next)
> > + break;
> > +
> > + if (rq_data_dir(cur) != rq_data_dir(next)) {
> > + blk_requeue_request(q, next);
> > + break;
> > + }
> > +
> > + if (mmc_req_rel_wr(next)&&
> > + (md->flags& MMC_BLK_REL_WR)&&
> > + !en_rel_wr) {
> > + blk_requeue_request(q, next);
> > + break;
> > + }
> > +
> > + req_sectors += blk_rq_sectors(next);
> > + if (req_sectors> max_blk_count) {
> > + blk_requeue_request(q, next);
> > + break;
> > + }
> > +
> > + phys_segments += next->nr_phys_segments;
> > + if (phys_segments> max_phys_segs) {
> > + blk_requeue_request(q, next);
> > + break;
> > + }
> > +
> > + list_add_tail(&next->queuelist,&mq->mqrq_cur->packed_list);
> > + cur = next;
> > + reqs++;
> > + }
> > +
> > + if (reqs> 0) {
> > + list_add(&req->queuelist,&mq->mqrq_cur->packed_list);
> > + return (reqs + 1);
> > + }
> > +
> > +no_packed:
> > + mq->mqrq_cur->packed_cmd = MMC_PACKED_NONE;
> > + return reqs;
> > +}
> > +
> >
> > 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)
> > @@ -1163,15 +1425,33 @@ 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_chk_packable(mq, rqc);
> > +
> > do {
> > if (rqc) {
> > - mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
> > + if (reqs>= 2) {
> > + mmc_blk_packed_hdr_wrq_prep(mq->mqrq_cur, card, mq, reqs);
> > + if (rq_data_dir(rqc) == READ) {
> > + areq =&mq->mqrq_cur->mmc_active;
> > + mmc_wait_for_req(card->host, areq->mrq);
> > + status = mmc_blk_packed_err_check(card, areq);
> > + if (status == MMC_BLK_SUCCESS) {
> > + mmc_blk_packed_rrq_prep(mq->mqrq_cur, card, mq);
> > + } else {
> > + goto check_status;
> > + }
> > + }
> > + } else {
> > + mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
>
> We must use disable_multi variable instead of directly calling this
> function with 0 value because there are some cases where disable_multi
> is set to 1 (for example, it is set for error case MMC_BLK_ECC_ERR).
This part is origin code for non-packed case.
It just is moved to else statement.
if (rqc) {
- mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);

>
> > + }
> > areq =&mq->mqrq_cur->mmc_active;
> > } else
> > areq = NULL;
> > @@ -1179,6 +1459,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
> > if (!areq)
> > return 0;
> >
> > +check_status:
> > mq_rq = container_of(areq, struct mmc_queue_req, mmc_active);
> > brq =&mq_rq->brq;
> > req = mq_rq->req;
> > @@ -1192,10 +1473,32 @@ 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);
> > + if (idx == i) {
> > + /* retry from error index */
> > + reqs -= idx;
> > + mq_rq->req = prq;
> > + ret = 1;
> > + break;
> > + }
> > + list_del_init(&prq->queuelist);
> > + spin_lock_irq(&md->lock);
> > + ret = __blk_end_request(prq, 0, blk_rq_bytes(prq));
> > + spin_unlock_irq(&md->lock);
> > + i++;
> > + }
> > + 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
> > @@ -1254,7 +1557,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
> > break;
> > }
> >
> > - if (ret) {
> > + if (ret&& (mq_rq->packed_cmd == MMC_PACKED_NONE)) {
> > /*
> > * In case of a incomplete request
> > * prepare it again and resend.
> > @@ -1267,13 +1570,37 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
> > return 1;
> >
> > cmd_abort:
> > - spin_lock_irq(&md->lock);
> > - 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);
> > + 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);
> > + blk_requeue_request(mq->queue, prq);
> > + } else {
> > + list_del_init(&prq->queuelist);
> > + }
> > + }
> > + }
> > mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
>
> We must use disable_multi variable instead of directly calling this
> function with 0 value because there are some cases where disable_multi
> is set to 1.
This part is also origin code for non-packed case.
>
> > mmc_start_req(card->host,&mq->mqrq_cur->mmc_active, NULL);
>
> I think these two statements must come under else part of above if
> condition. Please check.
This two statements are applicable regardless of packed command.

Best regards,
Seungwon Jeon.
>
> Thanks,
> Sahitya.
> --
> Sent by a consultant of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
> Forum.