dmaengine: xilinx_vdma: Simplify spin lock handling

This patch simplifies the spin lock handling in the driver
by moving locking out of xilinx_dma_start_transfer() API
and xilinx_dma_update_completed_cookie() API.

Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

diff --git a/drivers/dma/xilinx/xilinx_vdma.c b/drivers/dma/xilinx/xilinx_vdma.c
index e96ff9dea40da7f37075b1e5704c1a966b46a05a..70b2b32cba15d981169e8070e90f5220279df1ad 100644 (file)
--- a/drivers/dma/xilinx/xilinx_vdma.c
+++ b/drivers/dma/xilinx/xilinx_vdma.c
@@ -605,17 +605,15 @@ static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan)
 {
        struct xilinx_vdma_config *config = &chan->config;
        struct xilinx_vdma_tx_descriptor *desc, *tail_desc;
-       unsigned long flags;
        u32 reg;
        struct xilinx_vdma_tx_segment *tail_segment;
 
+       /* This function was invoked with lock held */
        if (chan->err)
                return;
 
-       spin_lock_irqsave(&chan->lock, flags);
-
        if (list_empty(&chan->pending_list))
-               goto out_unlock;
+               return;
 
        desc = list_first_entry(&chan->pending_list,
                                struct xilinx_vdma_tx_descriptor, node);
@@ -629,7 +627,7 @@ static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan)
        if (chan->has_sg && xilinx_vdma_is_running(chan) &&
            !xilinx_vdma_is_idle(chan)) {
                dev_dbg(chan->dev, "DMA controller still busy\n");
-               goto out_unlock;
+               return;
        }
 
        /*
@@ -680,7 +678,7 @@ static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan)
        xilinx_vdma_start(chan);
 
        if (chan->err)
-               goto out_unlock;
+               return;
 
        /* Start the transfer */
        if (chan->has_sg) {
@@ -700,7 +698,7 @@ static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan)
                }
 
                if (!last)
-                       goto out_unlock;
+                       return;
 
                /* HW expects these parameters to be same for one transaction */
                vdma_desc_write(chan, XILINX_VDMA_REG_HSIZE, last->hw.hsize);
@@ -711,9 +709,6 @@ static void xilinx_vdma_start_transfer(struct xilinx_vdma_chan *chan)
 
        list_splice_tail_init(&chan->pending_list, &chan->active_list);
        chan->desc_pendingcount = 0;
-
-out_unlock:
-       spin_unlock_irqrestore(&chan->lock, flags);
 }
 
 /**
@@ -723,8 +718,11 @@ out_unlock:
 static void xilinx_vdma_issue_pending(struct dma_chan *dchan)
 {
        struct xilinx_vdma_chan *chan = to_xilinx_chan(dchan);
+       unsigned long flags;
 
+       spin_lock_irqsave(&chan->lock, flags);
        xilinx_vdma_start_transfer(chan);
+       spin_unlock_irqrestore(&chan->lock, flags);
 }
 
 /**
@@ -736,21 +734,16 @@ static void xilinx_vdma_issue_pending(struct dma_chan *dchan)
 static void xilinx_vdma_complete_descriptor(struct xilinx_vdma_chan *chan)
 {
        struct xilinx_vdma_tx_descriptor *desc, *next;
-       unsigned long flags;
-
-       spin_lock_irqsave(&chan->lock, flags);
 
+       /* This function was invoked with lock held */
        if (list_empty(&chan->active_list))
-               goto out_unlock;
+               return;
 
        list_for_each_entry_safe(desc, next, &chan->active_list, node) {
                list_del(&desc->node);
                dma_cookie_complete(&desc->async_tx);
                list_add_tail(&desc->node, &chan->done_list);
        }
-
-out_unlock:
-       spin_unlock_irqrestore(&chan->lock, flags);
 }
 
 /**
@@ -861,8 +854,10 @@ static irqreturn_t xilinx_vdma_irq_handler(int irq, void *data)
        }
 
        if (status & XILINX_VDMA_DMASR_FRM_CNT_IRQ) {
+               spin_lock(&chan->lock);
                xilinx_vdma_complete_descriptor(chan);
                xilinx_vdma_start_transfer(chan);
+               spin_unlock(&chan->lock);
        }
 
        tasklet_schedule(&chan->tasklet);