fsldma: major cleanups and fixes

Fix locking. Use two queues in the driver, one for pending transacions, and
one for transactions which are actually running on the hardware. Call
dma_run_dependencies() on descriptor cleanup so that the async_tx API works
correctly.

There are a number of places throughout the code where lists of descriptors
are freed in a loop. Create functions to handle this, and use them instead
of open-coding the loop each time.

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

2 files changed, 207 insertions, 182 deletions

diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index 7b5f88cb495b..19011c20390b 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -61,7 +61,6 @@ static void dma_init(struct fsldma_chan *chan)
                                 | FSL_DMA_MR_PRC_RM, 32);
                 break;
         }
-
 }
 
 static void set_sr(struct fsldma_chan *chan, u32 val)
@@ -120,11 +119,6 @@ static dma_addr_t get_cdar(struct fsldma_chan *chan)
         return DMA_IN(chan, &chan->regs->cdar, 64) & ~FSL_DMA_SNEN;
 }
 
-static void set_ndar(struct fsldma_chan *chan, dma_addr_t addr)
-{
-        DMA_OUT(chan, &chan->regs->ndar, addr, 64);
-}
-
 static dma_addr_t get_ndar(struct fsldma_chan *chan)
 {
         return DMA_IN(chan, &chan->regs->ndar, 64);
@@ -178,11 +172,12 @@ static void dma_halt(struct fsldma_chan *chan)
 
         for (i = 0; i < 100; i++) {
                 if (dma_is_idle(chan))
-                        break;
+                        return;
+
                 udelay(10);
         }
 
-        if (i >= 100 && !dma_is_idle(chan))
+        if (!dma_is_idle(chan))
                 dev_err(chan->dev, "DMA halt timeout!\n");
 }
 
@@ -199,27 +194,6 @@ static void set_ld_eol(struct fsldma_chan *chan,
                         | snoop_bits, 64);
 }
 
-static void append_ld_queue(struct fsldma_chan *chan,
-                struct fsl_desc_sw *new_desc)
-{
-        struct fsl_desc_sw *queue_tail = to_fsl_desc(chan->ld_queue.prev);
-
-        if (list_empty(&chan->ld_queue))
-                return;
-
-        /* Link to the new descriptor physical address and
-         * Enable End-of-segment interrupt for
-         * the last link descriptor.
-         * (the previous node's next link descriptor)
-         *
-         * For FSL_DMA_IP_83xx, the snoop enable bit need be set.
-         */
-        queue_tail->hw.next_ln_addr = CPU_TO_DMA(chan,
-                        new_desc->async_tx.phys | FSL_DMA_EOSIE |
-                        (((chan->feature & FSL_DMA_IP_MASK)
-                                == FSL_DMA_IP_83XX) ? FSL_DMA_SNEN : 0), 64);
-}
-
 /**
  * fsl_chan_set_src_loop_size - Set source address hold transfer size
  * @chan : Freescale DMA channel
@@ -343,6 +317,31 @@ static void fsl_chan_toggle_ext_start(struct fsldma_chan *chan, int enable)
                 chan->feature &= ~FSL_DMA_CHAN_START_EXT;
 }
 
+static void append_ld_queue(struct fsldma_chan *chan,
+                            struct fsl_desc_sw *desc)
+{
+        struct fsl_desc_sw *tail = to_fsl_desc(chan->ld_pending.prev);
+
+        if (list_empty(&chan->ld_pending))
+                goto out_splice;
+
+        /*
+         * Add the hardware descriptor to the chain of hardware descriptors
+         * that already exists in memory.
+         *
+         * This will un-set the EOL bit of the existing transaction, and the
+         * last link in this transaction will become the EOL descriptor.
+         */
+        set_desc_next(chan, &tail->hw, desc->async_tx.phys);
+
+        /*
+         * Add the software descriptor and all children to the list
+         * of pending transactions
+         */
+out_splice:
+        list_splice_tail_init(&desc->tx_list, &chan->ld_pending);
+}
+
 static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
 {
         struct fsldma_chan *chan = to_fsl_chan(tx->chan);
@@ -351,9 +350,12 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
         unsigned long flags;
         dma_cookie_t cookie;
 
-        /* cookie increment and adding to ld_queue must be atomic */
         spin_lock_irqsave(&chan->desc_lock, flags);
 
+        /*
+         * assign cookies to all of the software descriptors
+         * that make up this transaction
+         */
         cookie = chan->common.cookie;
         list_for_each_entry(child, &desc->tx_list, node) {
                 cookie++;
@@ -364,8 +366,9 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
         }
 
         chan->common.cookie = cookie;
+
+        /* put this transaction onto the tail of the pending queue */
         append_ld_queue(chan, desc);
-        list_splice_init(&desc->tx_list, chan->ld_queue.prev);
 
         spin_unlock_irqrestore(&chan->desc_lock, flags);
 
@@ -381,20 +384,22 @@ static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
 static struct fsl_desc_sw *fsl_dma_alloc_descriptor(
                                         struct fsldma_chan *chan)
 {
+        struct fsl_desc_sw *desc;
         dma_addr_t pdesc;
-        struct fsl_desc_sw *desc_sw;
-
-        desc_sw = dma_pool_alloc(chan->desc_pool, GFP_ATOMIC, &pdesc);
-        if (desc_sw) {
-                memset(desc_sw, 0, sizeof(struct fsl_desc_sw));
-                INIT_LIST_HEAD(&desc_sw->tx_list);
-                dma_async_tx_descriptor_init(&desc_sw->async_tx,
-                                                &chan->common);
-                desc_sw->async_tx.tx_submit = fsl_dma_tx_submit;
-                desc_sw->async_tx.phys = pdesc;
+
+        desc = dma_pool_alloc(chan->desc_pool, GFP_ATOMIC, &pdesc);
+        if (!desc) {
+                dev_dbg(chan->dev, "out of memory for link desc\n");
+                return NULL;
         }
 
-        return desc_sw;
+        memset(desc, 0, sizeof(*desc));
+        INIT_LIST_HEAD(&desc->tx_list);
+        dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
+        desc->async_tx.tx_submit = fsl_dma_tx_submit;
+        desc->async_tx.phys = pdesc;
+
+        return desc;
 }
 
 
@@ -414,45 +419,69 @@ static int fsl_dma_alloc_chan_resources(struct dma_chan *dchan)
         if (chan->desc_pool)
                 return 1;
 
-        /* We need the descriptor to be aligned to 32bytes
+        /*
+         * We need the descriptor to be aligned to 32bytes
          * for meeting FSL DMA specification requirement.
          */
         chan->desc_pool = dma_pool_create("fsl_dma_engine_desc_pool",
-                        chan->dev, sizeof(struct fsl_desc_sw),
-                        32, 0);
+                                          chan->dev,
+                                          sizeof(struct fsl_desc_sw),
+                                          __alignof__(struct fsl_desc_sw), 0);
         if (!chan->desc_pool) {
-                dev_err(chan->dev, "No memory for channel %d "
-                        "descriptor dma pool.\n", chan->id);
-                return 0;
+                dev_err(chan->dev, "unable to allocate channel %d "
+                                   "descriptor pool\n", chan->id);
+                return -ENOMEM;
         }
 
+        /* there is at least one descriptor free to be allocated */
         return 1;
 }
 
 /**
+ * fsldma_free_desc_list - Free all descriptors in a queue
+ * @chan: Freescae DMA channel
+ * @list: the list to free
+ *
+ * LOCKING: must hold chan->desc_lock
+ */
+static void fsldma_free_desc_list(struct fsldma_chan *chan,
+                                  struct list_head *list)
+{
+        struct fsl_desc_sw *desc, *_desc;
+
+        list_for_each_entry_safe(desc, _desc, list, node) {
+                list_del(&desc->node);
+                dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
+        }
+}
+
+static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
+                                          struct list_head *list)
+{
+        struct fsl_desc_sw *desc, *_desc;
+
+        list_for_each_entry_safe_reverse(desc, _desc, list, node) {
+                list_del(&desc->node);
+                dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
+        }
+}
+
+/**
  * fsl_dma_free_chan_resources - Free all resources of the channel.
  * @chan : Freescale DMA channel
  */
 static void fsl_dma_free_chan_resources(struct dma_chan *dchan)
 {
         struct fsldma_chan *chan = to_fsl_chan(dchan);
-        struct fsl_desc_sw *desc, *_desc;
         unsigned long flags;
 
         dev_dbg(chan->dev, "Free all channel resources.\n");
         spin_lock_irqsave(&chan->desc_lock, flags);
-        list_for_each_entry_safe(desc, _desc, &chan->ld_queue, node) {
-#ifdef FSL_DMA_LD_DEBUG
-                dev_dbg(chan->dev,
-                                "LD %p will be released.\n", desc);
-#endif
-                list_del(&desc->node);
-                /* free link descriptor */
-                dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
-        }
+        fsldma_free_desc_list(chan, &chan->ld_pending);
+        fsldma_free_desc_list(chan, &chan->ld_running);
         spin_unlock_irqrestore(&chan->desc_lock, flags);
-        dma_pool_destroy(chan->desc_pool);
 
+        dma_pool_destroy(chan->desc_pool);
         chan->desc_pool = NULL;
 }
 
@@ -491,7 +520,6 @@ static struct dma_async_tx_descriptor *fsl_dma_prep_memcpy(
 {
         struct fsldma_chan *chan;
         struct fsl_desc_sw *first = NULL, *prev = NULL, *new;
-        struct list_head *list;
         size_t copy;
 
         if (!dchan)
@@ -550,12 +578,7 @@ fail:
         if (!first)
                 return NULL;
 
-        list = &first->tx_list;
-        list_for_each_entry_safe_reverse(new, prev, list, node) {
-                list_del(&new->node);
-                dma_pool_free(chan->desc_pool, new, new->async_tx.phys);
-        }
-
+        fsldma_free_desc_list_reverse(chan, &first->tx_list);
         return NULL;
 }
 
@@ -578,7 +601,6 @@ static struct dma_async_tx_descriptor *fsl_dma_prep_slave_sg(
         struct fsldma_chan *chan;
         struct fsl_desc_sw *first = NULL, *prev = NULL, *new = NULL;
         struct fsl_dma_slave *slave;
-        struct list_head *tx_list;
         size_t copy;
 
         int i;
@@ -748,19 +770,13 @@ fail:
          *
          * We're re-using variables for the loop, oh well
          */
-        tx_list = &first->tx_list;
-        list_for_each_entry_safe_reverse(new, prev, tx_list, node) {
-                list_del_init(&new->node);
-                dma_pool_free(chan->desc_pool, new, new->async_tx.phys);
-        }
-
+        fsldma_free_desc_list_reverse(chan, &first->tx_list);
         return NULL;
 }
 
 static void fsl_dma_device_terminate_all(struct dma_chan *dchan)
 {
         struct fsldma_chan *chan;
-        struct fsl_desc_sw *desc, *tmp;
         unsigned long flags;
 
         if (!dchan)
@@ -774,10 +790,8 @@ static void fsl_dma_device_terminate_all(struct dma_chan *dchan)
         spin_lock_irqsave(&chan->desc_lock, flags);
 
         /* Remove and free all of the descriptors in the LD queue */
-        list_for_each_entry_safe(desc, tmp, &chan->ld_queue, node) {
-                list_del(&desc->node);
-                dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
-        }
+        fsldma_free_desc_list(chan, &chan->ld_pending);
+        fsldma_free_desc_list(chan, &chan->ld_running);
 
         spin_unlock_irqrestore(&chan->desc_lock, flags);
 }
@@ -785,31 +799,48 @@ static void fsl_dma_device_terminate_all(struct dma_chan *dchan)
 /**
  * fsl_dma_update_completed_cookie - Update the completed cookie.
  * @chan : Freescale DMA channel
+ *
+ * CONTEXT: hardirq
  */
 static void fsl_dma_update_completed_cookie(struct fsldma_chan *chan)
 {
-        struct fsl_desc_sw *cur_desc, *desc;
-        dma_addr_t ld_phy;
-
-        ld_phy = get_cdar(chan) & FSL_DMA_NLDA_MASK;
+        struct fsl_desc_sw *desc;
+        unsigned long flags;
+        dma_cookie_t cookie;
 
-        if (ld_phy) {
-                cur_desc = NULL;
-                list_for_each_entry(desc, &chan->ld_queue, node)
-                        if (desc->async_tx.phys == ld_phy) {
-                                cur_desc = desc;
-                                break;
-                        }
+        spin_lock_irqsave(&chan->desc_lock, flags);
 
-                if (cur_desc && cur_desc->async_tx.cookie) {
-                        if (dma_is_idle(chan))
-                                chan->completed_cookie =
-                                        cur_desc->async_tx.cookie;
-                        else
-                                chan->completed_cookie =
-                                        cur_desc->async_tx.cookie - 1;
-                }
+        if (list_empty(&chan->ld_running)) {
+                dev_dbg(chan->dev, "no running descriptors\n");
+                goto out_unlock;
         }
+
+        /* Get the last descriptor, update the cookie to that */
+        desc = to_fsl_desc(chan->ld_running.prev);
+        if (dma_is_idle(chan))
+                cookie = desc->async_tx.cookie;
+        else
+                cookie = desc->async_tx.cookie - 1;
+
+        chan->completed_cookie = cookie;
+
+out_unlock:
+        spin_unlock_irqrestore(&chan->desc_lock, flags);
+}
+
+/**
+ * fsldma_desc_status - Check the status of a descriptor
+ * @chan: Freescale DMA channel
+ * @desc: DMA SW descriptor
+ *
+ * This function will return the status of the given descriptor
+ */
+static enum dma_status fsldma_desc_status(struct fsldma_chan *chan,
+                                          struct fsl_desc_sw *desc)
+{
+        return dma_async_is_complete(desc->async_tx.cookie,
+                                     chan->completed_cookie,
+                                     chan->common.cookie);
 }
 
 /**
@@ -817,8 +848,6 @@ static void fsl_dma_update_completed_cookie(struct fsldma_chan *chan)
  * @chan : Freescale DMA channel
  *
  * This function clean up the ld_queue of DMA channel.
- * If 'in_intr' is set, the function will move the link descriptor to
- * the recycle list. Otherwise, free it directly.
  */
 static void fsl_chan_ld_cleanup(struct fsldma_chan *chan)
 {
@@ -827,80 +856,95 @@ static void fsl_chan_ld_cleanup(struct fsldma_chan *chan)
 
         spin_lock_irqsave(&chan->desc_lock, flags);
 
-        dev_dbg(chan->dev, "chan completed_cookie = %d\n",
-                        chan->completed_cookie);
-        list_for_each_entry_safe(desc, _desc, &chan->ld_queue, node) {
+        dev_dbg(chan->dev, "chan completed_cookie = %d\n", chan->completed_cookie);
+        list_for_each_entry_safe(desc, _desc, &chan->ld_running, node) {
                 dma_async_tx_callback callback;
                 void *callback_param;
 
-                if (dma_async_is_complete(desc->async_tx.cookie,
-                            chan->completed_cookie, chan->common.cookie)
-                                == DMA_IN_PROGRESS)
+                if (fsldma_desc_status(chan, desc) == DMA_IN_PROGRESS)
                         break;
 
-                callback = desc->async_tx.callback;
-                callback_param = desc->async_tx.callback_param;
-
-                /* Remove from ld_queue list */
+                /* Remove from the list of running transactions */
                 list_del(&desc->node);
 
-                dev_dbg(chan->dev, "link descriptor %p will be recycle.\n",
-                                desc);
-                dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
-
                 /* Run the link descriptor callback function */
+                callback = desc->async_tx.callback;
+                callback_param = desc->async_tx.callback_param;
                 if (callback) {
                         spin_unlock_irqrestore(&chan->desc_lock, flags);
-                        dev_dbg(chan->dev, "link descriptor %p callback\n",
-                                        desc);
+                        dev_dbg(chan->dev, "LD %p callback\n", desc);
                         callback(callback_param);
                         spin_lock_irqsave(&chan->desc_lock, flags);
                 }
+
+                /* Run any dependencies, then free the descriptor */
+                dma_run_dependencies(&desc->async_tx);
+                dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
         }
+
         spin_unlock_irqrestore(&chan->desc_lock, flags);
 }
 
 /**
- * fsl_chan_xfer_ld_queue - Transfer link descriptors in channel ld_queue.
+ * fsl_chan_xfer_ld_queue - transfer any pending transactions
  * @chan : Freescale DMA channel
+ *
+ * This will make sure that any pending transactions will be run.
+ * If the DMA controller is idle, it will be started. Otherwise,
+ * the DMA controller's interrupt handler will start any pending
+ * transactions when it becomes idle.
  */
 static void fsl_chan_xfer_ld_queue(struct fsldma_chan *chan)
 {
-        struct list_head *ld_node;
-        dma_addr_t next_dst_addr;
+        struct fsl_desc_sw *desc;
         unsigned long flags;
 
         spin_lock_irqsave(&chan->desc_lock, flags);
 
-        if (!dma_is_idle(chan))
+        /*
+         * If the list of pending descriptors is empty, then we
+         * don't need to do any work at all
+         */
+        if (list_empty(&chan->ld_pending)) {
+                dev_dbg(chan->dev, "no pending LDs\n");
                 goto out_unlock;
+        }
 
+        /*
+         * The DMA controller is not idle, which means the interrupt
+         * handler will start any queued transactions when it runs
+         * at the end of the current transaction
+         */
+        if (!dma_is_idle(chan)) {
+                dev_dbg(chan->dev, "DMA controller still busy\n");
+                goto out_unlock;
+        }
+
+        /*
+         * TODO:
+         * make sure the dma_halt() function really un-wedges the
+         * controller as much as possible
+         */
         dma_halt(chan);
 
-        /* If there are some link descriptors
-         * not transfered in queue. We need to start it.
+        /*
+         * If there are some link descriptors which have not been
+         * transferred, we need to start the controller
          */
 
-        /* Find the first un-transfer desciptor */
-        for (ld_node = chan->ld_queue.next;
-                (ld_node != &chan->ld_queue)
-                        && (dma_async_is_complete(
-                                to_fsl_desc(ld_node)->async_tx.cookie,
-                                chan->completed_cookie,
-                                chan->common.cookie) == DMA_SUCCESS);
-                ld_node = ld_node->next);
-
-        if (ld_node != &chan->ld_queue) {
-                /* Get the ld start address from ld_queue */
-                next_dst_addr = to_fsl_desc(ld_node)->async_tx.phys;
-                dev_dbg(chan->dev, "xfer LDs staring from 0x%llx\n",
-                                (unsigned long long)next_dst_addr);
-                set_cdar(chan, next_dst_addr);
-                dma_start(chan);
-        } else {
-                set_cdar(chan, 0);
-                set_ndar(chan, 0);
-        }
+        /*
+         * Move all elements from the queue of pending transactions
+         * onto the list of running transactions
+         */
+        desc = list_first_entry(&chan->ld_pending, struct fsl_desc_sw, node);
+        list_splice_tail_init(&chan->ld_pending, &chan->ld_running);
+
+        /*
+         * Program the descriptor's address into the DMA controller,
+         * then start the DMA transaction
+         */
+        set_cdar(chan, desc->async_tx.phys);
+        dma_start(chan);
 
 out_unlock:
         spin_unlock_irqrestore(&chan->desc_lock, flags);
@@ -913,30 +957,6 @@ out_unlock:
 static void fsl_dma_memcpy_issue_pending(struct dma_chan *dchan)
 {
         struct fsldma_chan *chan = to_fsl_chan(dchan);
-
-#ifdef FSL_DMA_LD_DEBUG
-        struct fsl_desc_sw *ld;
-        unsigned long flags;
-
-        spin_lock_irqsave(&chan->desc_lock, flags);
-        if (list_empty(&chan->ld_queue)) {
-                spin_unlock_irqrestore(&chan->desc_lock, flags);
-                return;
-        }
-
-        dev_dbg(chan->dev, "--memcpy issue--\n");
-        list_for_each_entry(ld, &chan->ld_queue, node) {
-                int i;
-                dev_dbg(chan->dev, "Ch %d, LD %08x\n",
-                                chan->id, ld->async_tx.phys);
-                for (i = 0; i < 8; i++)
-                        dev_dbg(chan->dev, "LD offset %d: %08x\n",
-                                        i, *(((u32 *)&ld->hw) + i));
-        }
-        dev_dbg(chan->dev, "----------------\n");
-        spin_unlock_irqrestore(&chan->desc_lock, flags);
-#endif
-
         fsl_chan_xfer_ld_queue(chan);
 }
 
@@ -978,10 +998,10 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
         int xfer_ld_q = 0;
         u32 stat;
 
+        /* save and clear the status register */
         stat = get_sr(chan);
-        dev_dbg(chan->dev, "event: channel %d, stat = 0x%x\n",
-                                                chan->id, stat);
-        set_sr(chan, stat);             /* Clear the event register */
+        set_sr(chan, stat);
+        dev_dbg(chan->dev, "irq: channel %d, stat = 0x%x\n", chan->id, stat);
 
         stat &= ~(FSL_DMA_SR_CB | FSL_DMA_SR_CH);
         if (!stat)
@@ -990,12 +1010,13 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
         if (stat & FSL_DMA_SR_TE)
                 dev_err(chan->dev, "Transfer Error!\n");
 
-        /* Programming Error
+        /*
+         * Programming Error
          * The DMA_INTERRUPT async_tx is a NULL transfer, which will
          * triger a PE interrupt.
          */
         if (stat & FSL_DMA_SR_PE) {
-                dev_dbg(chan->dev, "event: Programming Error INT\n");
+                dev_dbg(chan->dev, "irq: Programming Error INT\n");
                 if (get_bcr(chan) == 0) {
                         /* BCR register is 0, this is a DMA_INTERRUPT async_tx.
                          * Now, update the completed cookie, and continue the
@@ -1007,34 +1028,37 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
                 stat &= ~FSL_DMA_SR_PE;
         }
 
-        /* If the link descriptor segment transfer finishes,
+        /*
+         * If the link descriptor segment transfer finishes,
          * we will recycle the used descriptor.
          */
         if (stat & FSL_DMA_SR_EOSI) {
-                dev_dbg(chan->dev, "event: End-of-segments INT\n");
-                dev_dbg(chan->dev, "event: clndar 0x%llx, nlndar 0x%llx\n",
+                dev_dbg(chan->dev, "irq: End-of-segments INT\n");
+                dev_dbg(chan->dev, "irq: clndar 0x%llx, nlndar 0x%llx\n",
                         (unsigned long long)get_cdar(chan),
                         (unsigned long long)get_ndar(chan));
                 stat &= ~FSL_DMA_SR_EOSI;
                 update_cookie = 1;
         }
 
-        /* For MPC8349, EOCDI event need to update cookie
+        /*
+         * For MPC8349, EOCDI event need to update cookie
          * and start the next transfer if it exist.
          */
         if (stat & FSL_DMA_SR_EOCDI) {
-                dev_dbg(chan->dev, "event: End-of-Chain link INT\n");
+                dev_dbg(chan->dev, "irq: End-of-Chain link INT\n");
                 stat &= ~FSL_DMA_SR_EOCDI;
                 update_cookie = 1;
                 xfer_ld_q = 1;
         }
 
-        /* If it current transfer is the end-of-transfer,
+        /*
+         * If it current transfer is the end-of-transfer,
          * we should clear the Channel Start bit for
          * prepare next transfer.
          */
         if (stat & FSL_DMA_SR_EOLNI) {
-                dev_dbg(chan->dev, "event: End-of-link INT\n");
+                dev_dbg(chan->dev, "irq: End-of-link INT\n");
                 stat &= ~FSL_DMA_SR_EOLNI;
                 xfer_ld_q = 1;
         }
@@ -1044,10 +1068,9 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
         if (xfer_ld_q)
                 fsl_chan_xfer_ld_queue(chan);
         if (stat)
-                dev_dbg(chan->dev, "event: unhandled sr 0x%02x\n",
-                                        stat);
+                dev_dbg(chan->dev, "irq: unhandled sr 0x%02x\n", stat);
 
-        dev_dbg(chan->dev, "event: Exit\n");
+        dev_dbg(chan->dev, "irq: Exit\n");
         tasklet_schedule(&chan->tasklet);
         return IRQ_HANDLED;
 }
@@ -1235,7 +1258,8 @@ static int __devinit fsl_dma_chan_probe(struct fsldma_device *fdev,
         }
 
         spin_lock_init(&chan->desc_lock);
-        INIT_LIST_HEAD(&chan->ld_queue);
+        INIT_LIST_HEAD(&chan->ld_pending);
+        INIT_LIST_HEAD(&chan->ld_running);
 
         chan->common.device = &fdev->common;
 
diff --git a/drivers/dma/fsldma.h b/drivers/dma/fsldma.h
index ea3b19c8708c..cb4d6ff51597 100644
--- a/drivers/dma/fsldma.h
+++ b/drivers/dma/fsldma.h
@@ -131,7 +131,8 @@ struct fsldma_chan {
         struct fsldma_chan_regs __iomem *regs;
         dma_cookie_t completed_cookie;  /* The maximum cookie completed */
         spinlock_t desc_lock;           /* Descriptor operation lock */
-        struct list_head ld_queue;      /* Link descriptors queue */
+        struct list_head ld_pending;    /* Link descriptors queue */
+        struct list_head ld_running;    /* Link descriptors queue */
         struct dma_chan common;         /* DMA common channel */
         struct dma_pool *desc_pool;     /* Descriptors pool */
         struct device *dev;             /* Channel device */