9 files changed, 191 insertions, 19 deletions

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 21056b9ef0a0..f79b4688e471 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -113,17 +113,6 @@ struct mmc_blk_data {
 
 static DEFINE_MUTEX(open_lock);
 
-enum mmc_blk_status {
-        MMC_BLK_SUCCESS = 0,
-        MMC_BLK_PARTIAL,
-        MMC_BLK_CMD_ERR,
-        MMC_BLK_RETRY,
-        MMC_BLK_ABORT,
-        MMC_BLK_DATA_ERR,
-        MMC_BLK_ECC_ERR,
-        MMC_BLK_NOMEDIUM,
-};
-
 module_param(perdev_minors, int, 0444);
 MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device");
 
@@ -1364,8 +1353,11 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
                 } else
                         areq = NULL;
                 areq = mmc_start_req(card->host, areq, (int *) &status);
-                if (!areq)
+                if (!areq) {
+                        if (status == MMC_BLK_NEW_REQUEST)
+                                mq->flags |= MMC_QUEUE_NEW_REQUEST;
                         return 0;
+                }
 
                 mq_rq = container_of(areq, struct mmc_queue_req, mmc_active);
                 brq = &mq_rq->brq;
@@ -1438,6 +1430,10 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
                         break;
                 case MMC_BLK_NOMEDIUM:
                         goto cmd_abort;
+                default:
+                        pr_err("%s: Unhandled return value (%d)",
+                                        req->rq_disk->disk_name, status);
+                        goto cmd_abort;
                 }
 
                 if (ret) {
@@ -1472,6 +1468,8 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
         int ret;
         struct mmc_blk_data *md = mq->data;
         struct mmc_card *card = md->queue.card;
+        struct mmc_host *host = card->host;
+        unsigned long flags;
 
         if (req && !mq->mqrq_prev->req)
                 /* claim host only for the first request */
@@ -1486,6 +1484,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
                 goto out;
         }
 
+        mq->flags &= ~MMC_QUEUE_NEW_REQUEST;
         if (req && req->cmd_flags & REQ_DISCARD) {
                 /* complete ongoing async transfer before issuing discard */
                 if (card->host->areq)
@@ -1501,11 +1500,16 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
                         mmc_blk_issue_rw_rq(mq, NULL);
                 ret = mmc_blk_issue_flush(mq, req);
         } else {
+                if (!req && host->areq) {
+                        spin_lock_irqsave(&host->context_info.lock, flags);
+                        host->context_info.is_waiting_last_req = true;
+                        spin_unlock_irqrestore(&host->context_info.lock, flags);
+                }
                 ret = mmc_blk_issue_rw_rq(mq, req);
         }
 
 out:
-        if (!req)
+        if (!req && !(mq->flags & MMC_QUEUE_NEW_REQUEST))
                 /* 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 d630d9861e7b..5e0971016ac5 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -22,7 +22,6 @@
 
 #define MMC_QUEUE_BOUNCESZ      65536
 
-#define MMC_QUEUE_SUSPENDED     (1 << 0)
 
 #define MMC_REQ_SPECIAL_MASK    (REQ_DISCARD | REQ_FLUSH)
 
@@ -72,6 +71,10 @@ static int mmc_queue_thread(void *d)
                         set_current_state(TASK_RUNNING);
                         cmd_flags = req ? req->cmd_flags : 0;
                         mq->issue_fn(mq, req);
+                        if (mq->flags & MMC_QUEUE_NEW_REQUEST) {
+                                mq->flags &= ~MMC_QUEUE_NEW_REQUEST;
+                                continue; /* fetch again */
+                        }
 
                         /*
                          * Current request becomes previous request
@@ -113,6 +116,8 @@ static void mmc_request_fn(struct request_queue *q)
 {
         struct mmc_queue *mq = q->queuedata;
         struct request *req;
+        unsigned long flags;
+        struct mmc_context_info *cntx;
 
         if (!mq) {
                 while ((req = blk_fetch_request(q)) != NULL) {
@@ -122,7 +127,20 @@ static void mmc_request_fn(struct request_queue *q)
                 return;
         }
 
-        if (!mq->mqrq_cur->req && !mq->mqrq_prev->req)
+        cntx = &mq->card->host->context_info;
+        if (!mq->mqrq_cur->req && mq->mqrq_prev->req) {
+                /*
+                 * New MMC request arrived when MMC thread may be
+                 * blocked on the previous request to be complete
+                 * with no current request fetched
+                 */
+                spin_lock_irqsave(&cntx->lock, flags);
+                if (cntx->is_waiting_last_req) {
+                        cntx->is_new_req = true;
+                        wake_up_interruptible(&cntx->wait);
+                }
+                spin_unlock_irqrestore(&cntx->lock, flags);
+        } else 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 d2a1eb4b9f9f..e20c27b2b8b4 100644
--- a/drivers/mmc/card/queue.h
+++ b/drivers/mmc/card/queue.h
@@ -27,6 +27,9 @@ struct mmc_queue {
         struct task_struct      *thread;
         struct semaphore        thread_sem;
         unsigned int            flags;
+#define MMC_QUEUE_SUSPENDED     (1 << 0)
+#define MMC_QUEUE_NEW_REQUEST   (1 << 1)
+
         int                     (*issue_fn)(struct mmc_queue *, struct request *);
         void                    *data;
         struct request_queue    *queue;
diff --git a/drivers/mmc/core/bus.c b/drivers/mmc/core/bus.c
index 420cb6753c1e..e219c97a02a4 100644
--- a/drivers/mmc/core/bus.c
+++ b/drivers/mmc/core/bus.c
@@ -321,6 +321,7 @@ int mmc_add_card(struct mmc_card *card)
 #ifdef CONFIG_DEBUG_FS
         mmc_add_card_debugfs(card);
 #endif
+        mmc_init_context_info(card->host);
 
         ret = device_add(&card->dev);
         if (ret)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index aaed7687cf09..8b3a1222e665 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -319,11 +319,44 @@ out:
 }
 EXPORT_SYMBOL(mmc_start_bkops);
 
+/*
+ * mmc_wait_data_done() - done callback for data request
+ * @mrq: done data request
+ *
+ * Wakes up mmc context, passed as a callback to host controller driver
+ */
+static void mmc_wait_data_done(struct mmc_request *mrq)
+{
+        mrq->host->context_info.is_done_rcv = true;
+        wake_up_interruptible(&mrq->host->context_info.wait);
+}
+
 static void mmc_wait_done(struct mmc_request *mrq)
 {
         complete(&mrq->completion);
 }
 
+/*
+ *__mmc_start_data_req() - starts data request
+ * @host: MMC host to start the request
+ * @mrq: data request to start
+ *
+ * Sets the done callback to be called when request is completed by the card.
+ * Starts data mmc request execution
+ */
+static int __mmc_start_data_req(struct mmc_host *host, struct mmc_request *mrq)
+{
+        mrq->done = mmc_wait_data_done;
+        mrq->host = host;
+        if (mmc_card_removed(host->card)) {
+                mrq->cmd->error = -ENOMEDIUM;
+                return -ENOMEDIUM;
+        }
+        mmc_start_request(host, mrq);
+
+        return 0;
+}
+
 static int __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq)
 {
         init_completion(&mrq->completion);
@@ -337,6 +370,62 @@ static int __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq)
         return 0;
 }
 
+/*
+ * mmc_wait_for_data_req_done() - wait for request completed
+ * @host: MMC host to prepare the command.
+ * @mrq: MMC request to wait for
+ *
+ * Blocks MMC context till host controller will ack end of data request
+ * execution or new request notification arrives from the block layer.
+ * Handles command retries.
+ *
+ * Returns enum mmc_blk_status after checking errors.
+ */
+static int mmc_wait_for_data_req_done(struct mmc_host *host,
+                                      struct mmc_request *mrq,
+                                      struct mmc_async_req *next_req)
+{
+        struct mmc_command *cmd;
+        struct mmc_context_info *context_info = &host->context_info;
+        int err;
+        unsigned long flags;
+
+        while (1) {
+                wait_event_interruptible(context_info->wait,
+                                (context_info->is_done_rcv ||
+                                 context_info->is_new_req));
+                spin_lock_irqsave(&context_info->lock, flags);
+                context_info->is_waiting_last_req = false;
+                spin_unlock_irqrestore(&context_info->lock, flags);
+                if (context_info->is_done_rcv) {
+                        context_info->is_done_rcv = false;
+                        context_info->is_new_req = false;
+                        cmd = mrq->cmd;
+                        if (!cmd->error || !cmd->retries ||
+                            mmc_card_removed(host->card)) {
+                                err = host->areq->err_check(host->card,
+                                                            host->areq);
+                                break; /* return err */
+                        } else {
+                                pr_info("%s: req failed (CMD%u): %d, retrying...\n",
+                                        mmc_hostname(host),
+                                        cmd->opcode, cmd->error);
+                                cmd->retries--;
+                                cmd->error = 0;
+                                host->ops->request(host, mrq);
+                                continue; /* wait for done/new event again */
+                        }
+                } else if (context_info->is_new_req) {
+                        context_info->is_new_req = false;
+                        if (!next_req) {
+                                err = MMC_BLK_NEW_REQUEST;
+                                break; /* return err */
+                        }
+                }
+        }
+        return err;
+}
+
 static void mmc_wait_for_req_done(struct mmc_host *host,
                                   struct mmc_request *mrq)
 {
@@ -426,8 +515,17 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
                 mmc_pre_req(host, areq->mrq, !host->areq);
 
         if (host->areq) {
-                mmc_wait_for_req_done(host, host->areq->mrq);
-                err = host->areq->err_check(host->card, host->areq);
+                        err = mmc_wait_for_data_req_done(host, host->areq->mrq,
+                                        areq);
+                        if (err == MMC_BLK_NEW_REQUEST) {
+                                if (error)
+                                        *error = err;
+                                /*
+                                 * The previous request was not completed,
+                                 * nothing to return
+                                 */
+                                return NULL;
+                        }
                 /*
                  * Check BKOPS urgency for each R1 response
                  */
@@ -439,7 +537,7 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host,
         }
 
         if (!err && areq)
-                start_err = __mmc_start_req(host, areq->mrq);
+                start_err = __mmc_start_data_req(host, areq->mrq);
 
         if (host->areq)
                 mmc_post_req(host, host->areq->mrq, 0);
@@ -2581,6 +2679,23 @@ int mmc_pm_notify(struct notifier_block *notify_block,
 }
 #endif
 
+/**
+ * mmc_init_context_info() - init synchronization context
+ * @host: mmc host
+ *
+ * Init struct context_info needed to implement asynchronous
+ * request mechanism, used by mmc core, host driver and mmc requests
+ * supplier.
+ */
+void mmc_init_context_info(struct mmc_host *host)
+{
+        spin_lock_init(&host->context_info.lock);
+        host->context_info.is_new_req = false;
+        host->context_info.is_done_rcv = false;
+        host->context_info.is_waiting_last_req = false;
+        init_waitqueue_head(&host->context_info.wait);
+}
+
 static int __init mmc_init(void)
 {
         int ret;
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 3bdafbca354f..0272b3284b5e 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -76,5 +76,6 @@ void mmc_remove_host_debugfs(struct mmc_host *host);
 void mmc_add_card_debugfs(struct mmc_card *card);
 void mmc_remove_card_debugfs(struct mmc_card *card);
 
+void mmc_init_context_info(struct mmc_host *host);
 #endif
 
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 5c69315d60cc..be2500a49925 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -187,6 +187,18 @@ struct sdio_func_tuple;
 
 #define SDIO_MAX_FUNCS          7
 
+enum mmc_blk_status {
+        MMC_BLK_SUCCESS = 0,
+        MMC_BLK_PARTIAL,
+        MMC_BLK_CMD_ERR,
+        MMC_BLK_RETRY,
+        MMC_BLK_ABORT,
+        MMC_BLK_DATA_ERR,
+        MMC_BLK_ECC_ERR,
+        MMC_BLK_NOMEDIUM,
+        MMC_BLK_NEW_REQUEST,
+};
+
 /* The number of MMC physical partitions.  These consist of:
  * boot partitions (2), general purpose partitions (4) in MMC v4.4.
  */
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 5bf7c2274fcb..495d1336149c 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -120,6 +120,7 @@ struct mmc_data {
         s32                     host_cookie;    /* host private data */
 };
 
+struct mmc_host;
 struct mmc_request {
         struct mmc_command      *sbc;           /* SET_BLOCK_COUNT for multiblock */
         struct mmc_command      *cmd;
@@ -128,9 +129,9 @@ struct mmc_request {
 
         struct completion       completion;
         void                    (*done)(struct mmc_request *);/* completion function */
+        struct mmc_host         *host;
 };
 
-struct mmc_host;
 struct mmc_card;
 struct mmc_async_req;
 
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index c89a1bb87fa5..523d570f58ad 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -170,6 +170,22 @@ struct mmc_slot {
         void *handler_priv;
 };
 
+/**
+ * mmc_context_info - synchronization details for mmc context
+ * @is_done_rcv         wake up reason was done request
+ * @is_new_req          wake up reason was new request
+ * @is_waiting_last_req mmc context waiting for single running request
+ * @wait                wait queue
+ * @lock                lock to protect data fields
+ */
+struct mmc_context_info {
+        bool                    is_done_rcv;
+        bool                    is_new_req;
+        bool                    is_waiting_last_req;
+        wait_queue_head_t       wait;
+        spinlock_t              lock;
+};
+
 struct regulator;
 
 struct mmc_supply {
@@ -331,6 +347,7 @@ struct mmc_host {
         struct dentry           *debugfs_root;
 
         struct mmc_async_req    *areq;          /* active async req */
+        struct mmc_context_info context_info;   /* async synchronization info */
 
 #ifdef CONFIG_FAIL_MMC_REQUEST
         struct fault_attr       fail_mmc_request;