mmc: block: add handling for two parallel block requests in issue_rw_rq

Change mmc_blk_issue_rw_rq() to become asynchronous.
The execution flow looks like this:

* The mmc-queue calls issue_rw_rq(), which sends the request
  to the host and returns back to the mmc-queue.
* The mmc-queue calls issue_rw_rq() again with a new request.
* This new request is prepared in issue_rw_rq(), then it waits for
  the active request to complete before pushing it to the host.
* When the mmc-queue is empty it will call issue_rw_rq() with a NULL
  req to finish off the active request without starting a new request.

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Venkatraman S <svenkatr@ti.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 7ed2c68e8763c03fd5c0f053a770051e13866e4a..38d01492a52bca84afbf034c4d40a8a165545289 100644 (file)
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -822,12 +822,14 @@ static inline void mmc_apply_rel_rw(struct mmc_blk_request *brq,
         R1_CC_ERROR |          /* Card controller error */             \
         R1_ERROR)              /* General/unknown error */
 
-int mmc_blk_err_check(struct mmc_blk_request *brq,
-                     struct request *req,
-                     struct mmc_card *card,
-                     struct mmc_blk_data *md)
+static int mmc_blk_err_check(struct mmc_card *card,
+                            struct mmc_async_req *areq)
 {
-       int ret = MMC_BLK_SUCCESS;
+       enum mmc_blk_status ret = MMC_BLK_SUCCESS;
+       struct mmc_queue_req *mq_mrq = container_of(areq, struct mmc_queue_req,
+                                                   mmc_active);
+       struct mmc_blk_request *brq = &mq_mrq->brq;
+       struct request *req = mq_mrq->req;
 
        /*
         * sbc.error indicates a problem with the set block count
@@ -1038,24 +1040,41 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
                brq->data.sg_len = i;
        }
 
+       mqrq->mmc_active.mrq = &brq->mrq;
+       mqrq->mmc_active.err_check = mmc_blk_err_check;
+
        mmc_queue_bounce_pre(mqrq);
 }
 
-static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
+static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
 {
        struct mmc_blk_data *md = mq->data;
        struct mmc_card *card = md->queue.card;
        struct mmc_blk_request *brq = &mq->mqrq_cur->brq;
        int ret = 1, disable_multi = 0, retry = 0;
        enum mmc_blk_status status;
+       struct mmc_queue_req *mq_rq;
+       struct request *req;
+       struct mmc_async_req *areq;
 
-       do {
-               mmc_blk_rw_rq_prep(mq->mqrq_cur, card, disable_multi, mq);
-               mmc_wait_for_req(card->host, &brq->mrq);
+       if (!rqc && !mq->mqrq_prev->req)
+               return 0;
 
-               mmc_queue_bounce_post(mq->mqrq_cur);
+       do {
+               if (rqc) {
+                       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;
+
+               mq_rq = container_of(areq, struct mmc_queue_req, mmc_active);
+               brq = &mq_rq->brq;
+               req = mq_rq->req;
+               mmc_queue_bounce_post(mq_rq);
 
-               status = mmc_blk_err_check(brq, req, card, md);
                switch (status) {
                case MMC_BLK_SUCCESS:
                case MMC_BLK_PARTIAL:
@@ -1066,6 +1085,19 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
                        ret = __blk_end_request(req, 0,
                                                brq->data.bytes_xfered);
                        spin_unlock_irq(&md->lock);
+                       if (status == MMC_BLK_SUCCESS && ret) {
+                               /*
+                                * The blk_end_request has returned non zero
+                                * even though all data is transfered and no
+                                * erros returned by host.
+                                * If this happen it's a bug.
+                                */
+                               printk(KERN_ERR "%s BUG rq_tot %d d_xfer %d\n",
+                                      __func__, blk_rq_bytes(req),
+                                      brq->data.bytes_xfered);
+                               rqc = NULL;
+                               goto cmd_abort;
+                       }
                        break;
                case MMC_BLK_CMD_ERR:
                        goto cmd_err;
@@ -1087,9 +1119,19 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
                        ret = __blk_end_request(req, -EIO,
                                                brq->data.blksz);
                        spin_unlock_irq(&md->lock);
+                       if (!ret)
+                               goto start_new_req;
                        break;
                }
 
+               if (ret) {
+                       /*
+                        * In case of a none complete 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);
+               }
        } while (ret);
 
        return 1;
@@ -1124,6 +1166,12 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
                ret = __blk_end_request(req, -EIO, blk_rq_cur_bytes(req));
        spin_unlock_irq(&md->lock);
 
+ start_new_req:
+       if (rqc) {
+               mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
+               mmc_start_req(card->host, &mq->mqrq_cur->mmc_active, NULL);
+       }
+
        return 0;
 }
 
@@ -1133,26 +1181,34 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
        struct mmc_blk_data *md = mq->data;
        struct mmc_card *card = md->queue.card;
 
-       mmc_claim_host(card->host);
+       if (req && !mq->mqrq_prev->req)
+               /* claim host only for the first request */
+               mmc_claim_host(card->host);
+
        ret = mmc_blk_part_switch(card, md);
        if (ret) {
                ret = 0;
                goto out;
        }
 
-       if (req->cmd_flags & REQ_DISCARD) {
+       if (req && req->cmd_flags & REQ_DISCARD) {
+               /* complete ongoing async transfer before issuing discard */
+               if (card->host->areq)
+                       mmc_blk_issue_rw_rq(mq, NULL);
                if (req->cmd_flags & REQ_SECURE)
                        ret = mmc_blk_issue_secdiscard_rq(mq, req);
                else
                        ret = mmc_blk_issue_discard_rq(mq, req);
-       } else if (req->cmd_flags & REQ_FLUSH) {
+       } else if (req && req->cmd_flags & REQ_FLUSH) {
                ret = mmc_blk_issue_flush(mq, req);
        } else {
                ret = mmc_blk_issue_rw_rq(mq, req);
        }
 
 out:
-       mmc_release_host(card->host);
+       if (!req)
+               /* release host only when there are no more requests */
+               mmc_release_host(card->host);
        return ret;
 }
 

diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index a38d310f503028f3c2094192fcd8fe434a37a4e6..45fb362e3f013460fc951909dc72d13847530a1e 100644 (file)
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -52,6 +52,7 @@ static int mmc_queue_thread(void *d)
        down(&mq->thread_sem);
        do {
                struct request *req = NULL;
+               struct mmc_queue_req *tmp;
 
                spin_lock_irq(q->queue_lock);
                set_current_state(TASK_INTERRUPTIBLE);
@@ -59,7 +60,10 @@ static int mmc_queue_thread(void *d)
                mq->mqrq_cur->req = req;
                spin_unlock_irq(q->queue_lock);
 
-               if (!req) {
+               if (req || mq->mqrq_prev->req) {
+                       set_current_state(TASK_RUNNING);
+                       mq->issue_fn(mq, req);
+               } else {
                        if (kthread_should_stop()) {
                                set_current_state(TASK_RUNNING);
                                break;
@@ -67,11 +71,14 @@ static int mmc_queue_thread(void *d)
                        up(&mq->thread_sem);
                        schedule();
                        down(&mq->thread_sem);
-                       continue;
                }
-               set_current_state(TASK_RUNNING);
 
-               mq->issue_fn(mq, req);
+               /* Current request becomes previous request and vice versa. */
+               mq->mqrq_prev->brq.mrq.data = NULL;
+               mq->mqrq_prev->req = NULL;
+               tmp = mq->mqrq_prev;
+               mq->mqrq_prev = mq->mqrq_cur;
+               mq->mqrq_cur = tmp;
        } while (1);
        up(&mq->thread_sem);
 
@@ -97,7 +104,7 @@ static void mmc_request(struct request_queue *q)
                return;
        }
 
-       if (!mq->mqrq_cur->req)
+       if (!mq->mqrq_cur->req && !mq->mqrq_prev->req)
                wake_up_process(mq->thread);
 }
 

diff --git a/drivers/mmc/card/queue.h b/drivers/mmc/card/queue.h
index 1a637d2e2ca693d298570c875e52c248bd0028d9..d2a1eb4b9f9fade36848726f4e36fc4db1463cca 100644 (file)
--- a/drivers/mmc/card/queue.h
+++ b/drivers/mmc/card/queue.h
@@ -19,6 +19,7 @@ struct mmc_queue_req {
        char                    *bounce_buf;
        struct scatterlist      *bounce_sg;
        unsigned int            bounce_sg_len;
+       struct mmc_async_req    mmc_active;
 };
 
 struct mmc_queue {