[PATCH 10/14] dmaengine: mxs: Drop unnecessary flag

Sascha Hauer s.hauer at pengutronix.de
Thu Apr 25 05:56:39 PDT 2019


The mxs dma driver insists on having the DMA_PREP_INTERRUPT flag set
on all but the first transfer. There's no need to let the user set this
flag, the driver can do it internally whenever it needs it. Drop
handling of this flag from the driver.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
Acked-by: Vinod Koul <vkoul at kernel.org>
---
 drivers/dma/mxs-dma.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
index 22cc7f68ef6e..ce92a3626ea4 100644
--- a/drivers/dma/mxs-dma.c
+++ b/drivers/dma/mxs-dma.c
@@ -477,16 +477,16 @@ static void mxs_dma_free_chan_resources(struct dma_chan *chan)
  *            ......
  *            ->device_prep_slave_sg(0);
  *            ......
- *            ->device_prep_slave_sg(DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ *            ->device_prep_slave_sg(DMA_CTRL_ACK);
  *            ......
  *    [3] If there are more than two DMA commands in the DMA chain, the code
  *        should be:
  *            ......
  *            ->device_prep_slave_sg(0);                                // First
  *            ......
- *            ->device_prep_slave_sg(DMA_PREP_INTERRUPT [| DMA_CTRL_ACK]);
+ *            ->device_prep_slave_sg(DMA_CTRL_ACK]);
  *            ......
- *            ->device_prep_slave_sg(DMA_PREP_INTERRUPT | DMA_CTRL_ACK); // Last
+ *            ->device_prep_slave_sg(DMA_CTRL_ACK); // Last
  *            ......
  */
 static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
@@ -500,13 +500,12 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
 	struct scatterlist *sg;
 	u32 i, j;
 	u32 *pio;
-	bool append = flags & DMA_PREP_INTERRUPT;
-	int idx = append ? mxs_chan->desc_count : 0;
+	int idx = 0;
 
-	if (mxs_chan->status == DMA_IN_PROGRESS && !append)
-		return NULL;
+	if (mxs_chan->status == DMA_IN_PROGRESS)
+		idx = mxs_chan->desc_count;
 
-	if (sg_len + (append ? idx : 0) > NUM_CCW) {
+	if (sg_len + idx > NUM_CCW) {
 		dev_err(mxs_dma->dma_device.dev,
 				"maximum number of sg exceeded: %d > %d\n",
 				sg_len, NUM_CCW);
@@ -520,7 +519,7 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
 	 * If the sg is prepared with append flag set, the sg
 	 * will be appended to the last prepared sg.
 	 */
-	if (append) {
+	if (idx) {
 		BUG_ON(idx < 1);
 		ccw = &mxs_chan->ccw[idx - 1];
 		ccw->next = mxs_chan->ccw_phys + sizeof(*ccw) * idx;
-- 
2.20.1




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