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

[Sahitya Tummala <stummala@codeaurora.org>]

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?

> +}
> +
>   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?

> +		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).

> +			}
>   			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.

>   		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.

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.