@@ -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;
}
/*
@@ -676,7 +674,7 @@ 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) {
@@ -696,7 +694,7 @@ 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);
@@ -707,9 +705,6 @@ 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);
}
/**
@@ -719,8 +714,11 @@ 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);
}
/**
@@ -732,21 +730,16 @@ 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);
}
/**
@@ -857,8 +850,10 @@ 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);
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> --- Changes for v3: ---> Updated commit message as suggested by vinod. ---> Added description to the API's(start_transfer/complete_cookie) regarding locking as suggested by vinod. Changes for v2: ---> splitted the changes into multiple patches drivers/dma/xilinx/xilinx_vdma.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-)