[PATCH 1/2] dmaengine: Fix status handling in imx-dma.

[Javier Martin]

Status must only be changed to DMA_IN_PROGRESS
when the DMA transfer has really begun.

However, since this driver lacks of support for
multiple descriptors a new flag has to be introduced
to avoid the prepare function be called multiple times.

Signed-off-by: Javier Martin <javier.martin at vista-silicon.com>
---
 drivers/dma/imx-dma.c |   22 +++++++++++++++-------
 1 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
index d99f71c..9a0ac14 100644
--- a/drivers/dma/imx-dma.c
+++ b/drivers/dma/imx-dma.c
@@ -43,6 +43,7 @@ struct imxdma_channel {
 	enum dma_status			status;
 	int				dma_request;
 	struct scatterlist		*sg_list;
+	bool				prepared;
 };
 
 #define MAX_DMA_CHANNELS 8
@@ -72,6 +73,7 @@ static void imxdma_irq_handler(int channel, void *data)
 
 	imxdmac->status = DMA_SUCCESS;
 	imxdma_handle(imxdmac);
+	imxdmac->prepared = false;
 }
 
 static void imxdma_err_handler(int channel, void *data, int error)
@@ -80,6 +82,7 @@ static void imxdma_err_handler(int channel, void *data, int error)
 
 	imxdmac->status = DMA_ERROR;
 	imxdma_handle(imxdmac);
+	imxdmac->prepared = false;
 }
 
 static void imxdma_progression(int channel, void *data,
@@ -89,6 +92,7 @@ static void imxdma_progression(int channel, void *data,
 
 	imxdmac->status = DMA_SUCCESS;
 	imxdma_handle(imxdmac);
+	imxdmac->prepared = false;
 }
 
 static int imxdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
@@ -103,6 +107,7 @@ static int imxdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
 	case DMA_TERMINATE_ALL:
 		imxdmac->status = DMA_ERROR;
 		imx_dma_disable(imxdmac->imxdma_channel);
+		imxdmac->prepared = false;
 		return 0;
 	case DMA_SLAVE_CONFIG:
 		if (dmaengine_cfg->direction == DMA_FROM_DEVICE) {
@@ -204,7 +209,7 @@ static int imxdma_alloc_chan_resources(struct dma_chan *chan)
 	imxdmac->desc.flags = DMA_CTRL_ACK;
 
 	imxdmac->status = DMA_SUCCESS;
-
+	imxdmac->prepared = false;
 	return 0;
 }
 
@@ -230,11 +235,9 @@ static struct dma_async_tx_descriptor *imxdma_prep_slave_sg(
 	int i, ret, dma_length = 0;
 	unsigned int dmamode;
 
-	if (imxdmac->status == DMA_IN_PROGRESS)
+	if (imxdmac->prepared)
 		return NULL;
 
-	imxdmac->status = DMA_IN_PROGRESS;
-
 	for_each_sg(sgl, sg, sg_len, i) {
 		dma_length += sg->length;
 	}
@@ -264,6 +267,8 @@ static struct dma_async_tx_descriptor *imxdma_prep_slave_sg(
 	if (ret)
 		return NULL;
 
+	imxdmac->prepared = true;
+
 	return &imxdmac->desc;
 }
 
@@ -280,9 +285,8 @@ static struct dma_async_tx_descriptor *imxdma_prep_dma_cyclic(
 	dev_dbg(imxdma->dev, "%s channel: %d buf_len=%d period_len=%d\n",
 			__func__, imxdmac->channel, buf_len, period_len);
 
-	if (imxdmac->status == DMA_IN_PROGRESS)
+	if (imxdmac->prepared)
 		return NULL;
-	imxdmac->status = DMA_IN_PROGRESS;
 
 	ret = imx_dma_setup_progression_handler(imxdmac->imxdma_channel,
 			imxdma_progression);
@@ -325,14 +329,18 @@ static struct dma_async_tx_descriptor *imxdma_prep_dma_cyclic(
 	if (ret)
 		return NULL;
 
+	imxdmac->prepared = true;
+
 	return &imxdmac->desc;
 }
 
 static void imxdma_issue_pending(struct dma_chan *chan)
 {
 	/*
-	 * Nothing to do. We only have a single descriptor
+	 * Only change status since we have a single descriptor
 	 */
+	struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
+	imxdmac->status = DMA_IN_PROGRESS;
 }
 
 static int __init imxdma_probe(struct platform_device *pdev)
-- 
1.7.0.4