dmaengine: PL08x: convert to a list of completed descriptors

Convert PL08x to use a list of completed descriptors rather than
merely relying upon a single pointer.  This makes it possible to
schedule the tasklet for other purposes, and makes our behaviour
similar to virt-dma.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index ac9fdcc..54e3eb0 100644 (file)
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -219,6 +219,7 @@ enum pl08x_dma_chan_state {
  * @cd: channel platform data
  * @runtime_addr: address for RX/TX according to the runtime config
  * @pend_list: queued transactions pending on this channel
+ * @done_list: list of completed transactions
  * @at: active transaction on this channel
  * @lock: a lock for this channel data
  * @host: a pointer to the host (internal use)
@@ -238,6 +239,7 @@ struct pl08x_dma_chan {
        const struct pl08x_channel_data *cd;
        struct dma_slave_config cfg;
        struct list_head pend_list;
+       struct list_head done_list;
        struct pl08x_txd *at;
        spinlock_t lock;
        struct pl08x_driver_data *host;
@@ -1673,18 +1675,11 @@ static void pl08x_tasklet(unsigned long data)
 {
        struct pl08x_dma_chan *plchan = (struct pl08x_dma_chan *) data;
        struct pl08x_driver_data *pl08x = plchan->host;
-       struct pl08x_txd *txd;
        unsigned long flags;
+       LIST_HEAD(head);
 
        spin_lock_irqsave(&plchan->lock, flags);
-
-       txd = plchan->at;
-       plchan->at = NULL;
-
-       if (txd) {
-               /* Update last completed */
-               dma_cookie_complete(&txd->tx);
-       }
+       list_splice_tail_init(&plchan->done_list, &head);
 
        /* If a new descriptor is queued, set it up plchan->at is NULL here */
        if (!list_empty(&plchan->pend_list)) {
@@ -1739,10 +1734,14 @@ static void pl08x_tasklet(unsigned long data)
 
        spin_unlock_irqrestore(&plchan->lock, flags);
 
-       if (txd) {
+       while (!list_empty(&head)) {
+               struct pl08x_txd *txd = list_first_entry(&head,
+                                               struct pl08x_txd, node);
                dma_async_tx_callback callback = txd->tx.callback;
                void *callback_param = txd->tx.callback_param;
 
+               list_del(&txd->node);
+
                /* Don't try to unmap buffers on slave channels */
                if (!plchan->slave)
                        pl08x_unmap_buffers(txd);
@@ -1782,6 +1781,7 @@ static irqreturn_t pl08x_irq(int irq, void *dev)
                        /* Locate physical channel */
                        struct pl08x_phy_chan *phychan = &pl08x->phy_chans[i];
                        struct pl08x_dma_chan *plchan = phychan->serving;
+                       struct pl08x_txd *tx;
 
                        if (!plchan) {
                                dev_err(&pl08x->adev->dev,
@@ -1790,6 +1790,15 @@ static irqreturn_t pl08x_irq(int irq, void *dev)
                                continue;
                        }
 
+                       spin_lock(&plchan->lock);
+                       tx = plchan->at;
+                       if (tx) {
+                               plchan->at = NULL;
+                               dma_cookie_complete(&tx->tx);
+                               list_add_tail(&tx->node, &plchan->done_list);
+                       }
+                       spin_unlock(&plchan->lock);
+
                        /* Schedule tasklet on this channel */
                        tasklet_schedule(&plchan->tasklet);
                        mask |= (1 << i);
@@ -1856,6 +1865,7 @@ static int pl08x_dma_init_virtual_channels(struct pl08x_driver_data *pl08x,
 
                spin_lock_init(&chan->lock);
                INIT_LIST_HEAD(&chan->pend_list);
+               INIT_LIST_HEAD(&chan->done_list);
                tasklet_init(&chan->tasklet, pl08x_tasklet,
                             (unsigned long) chan);