[PATCH v3 0/4] media: pxa_camera conversion to dmaengine

[PATCH v3 0/4] media: pxa_camera conversion to dmaengine

[Robert Jarzmik]

Hi Guennadi,

This is the third round.

Most of this round deals with the sg_cut() polishing.
We still have a bit of ground to cover :
 (a) Robert: try to submit sg_split() to lib/sglist.c
 (b) Robert: following dmaengine "reuse" flag introduction, change pxa_camera
             accordingly
 (c) Guennadi: I think you had comments about free_buffer() I never received by
               mail, so there might be something to rework in this area.
 (d) Guennadi+Robert: continue review of the serie

Happy review.

Cheers.

--
Robert

Robert Jarzmik (4):
  media: pxa_camera: fix the buffer free path
  media: pxa_camera: move interrupt to tasklet
  media: pxa_camera: trivial move of dma irq functions
  media: pxa_camera: conversion to dmaengine

 drivers/media/platform/soc_camera/pxa_camera.c | 578 ++++++++++++++-----------
 1 file changed, 321 insertions(+), 257 deletions(-)

-- 
2.1.4

[PATCH v3 1/4] media: pxa_camera: fix the buffer free path

[Robert Jarzmik]

From: Robert Jarzmik <robert.jarzmik@intel.com>

Fix the error path where the video buffer wasn't allocated nor
mapped. In this case, in the driver free path don't try to unmap memory
which was not mapped in the first place.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
 drivers/media/platform/soc_camera/pxa_camera.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/soc_camera/pxa_camera.c b/drivers/media/platform/soc_camera/pxa_camera.c
index fcb942de0c7f..aa304950bb98 100644
--- a/drivers/media/platform/soc_camera/pxa_camera.c
+++ b/drivers/media/platform/soc_camera/pxa_camera.c
@@ -272,8 +272,8 @@ static void free_buffer(struct videobuf_queue *vq, struct pxa_buffer *buf)
 	 * longer in STATE_QUEUED or STATE_ACTIVE
 	 */
 	videobuf_waiton(vq, &buf->vb, 0, 0);
-	videobuf_dma_unmap(vq->dev, dma);
-	videobuf_dma_free(dma);
+	if (buf->vb.state == VIDEOBUF_NEEDS_INIT)
+		return;
 
 	for (i = 0; i < ARRAY_SIZE(buf->dmas); i++) {
 		if (buf->dmas[i].sg_cpu)
@@ -283,6 +283,8 @@ static void free_buffer(struct videobuf_queue *vq, struct pxa_buffer *buf)
 					  buf->dmas[i].sg_dma);
 		buf->dmas[i].sg_cpu = NULL;
 	}
+	videobuf_dma_unmap(vq->dev, dma);
+	videobuf_dma_free(dma);
 
 	buf->vb.state = VIDEOBUF_NEEDS_INIT;
 }
-- 
2.1.4

[PATCH v3 2/4] media: pxa_camera: move interrupt to tasklet

[Robert Jarzmik]

From: Robert Jarzmik <robert.jarzmik@intel.com>

In preparation for dmaengine conversion, move the camera interrupt
handling into a tasklet. This won't change the global flow, as this
interrupt is only used to detect the end of frame and activate DMA fifos
handling.

Signed-off-by: Robert Jarzmik <robert.jarzmik@intel.com>
---
 drivers/media/platform/soc_camera/pxa_camera.c | 44 +++++++++++++++++---------
 1 file changed, 29 insertions(+), 15 deletions(-)

diff --git a/drivers/media/platform/soc_camera/pxa_camera.c b/drivers/media/platform/soc_camera/pxa_camera.c
index aa304950bb98..39c7e7519b3c 100644
--- a/drivers/media/platform/soc_camera/pxa_camera.c
+++ b/drivers/media/platform/soc_camera/pxa_camera.c
@@ -223,6 +223,7 @@ struct pxa_camera_dev {
 
 	struct pxa_buffer	*active;
 	struct pxa_dma_desc	*sg_tail[3];
+	struct tasklet_struct	task_eof;
 
 	u32			save_cicr[5];
 };
@@ -605,6 +606,7 @@ static void pxa_camera_start_capture(struct pxa_camera_dev *pcdev)
 	unsigned long cicr0;
 
 	dev_dbg(pcdev->soc_host.v4l2_dev.dev, "%s\n", __func__);
+	__raw_writel(__raw_readl(pcdev->base + CISR), pcdev->base + CISR);
 	/* Enable End-Of-Frame Interrupt */
 	cicr0 = __raw_readl(pcdev->base + CICR0) | CICR0_ENB;
 	cicr0 &= ~CICR0_EOFM;
@@ -922,13 +924,35 @@ static void pxa_camera_deactivate(struct pxa_camera_dev *pcdev)
 	clk_disable_unprepare(pcdev->clk);
 }
 
-static irqreturn_t pxa_camera_irq(int irq, void *data)
+static void pxa_camera_eof(unsigned long arg)
 {
-	struct pxa_camera_dev *pcdev = data;
-	unsigned long status, cifr, cicr0;
+	struct pxa_camera_dev *pcdev = (struct pxa_camera_dev *)arg;
+	unsigned long cifr;
 	struct pxa_buffer *buf;
 	struct videobuf_buffer *vb;
 
+	dev_dbg(pcdev->soc_host.v4l2_dev.dev,
+		"Camera interrupt status 0x%x\n",
+		__raw_readl(pcdev->base + CISR));
+
+	/* Reset the FIFOs */
+	cifr = __raw_readl(pcdev->base + CIFR) | CIFR_RESET_F;
+	__raw_writel(cifr, pcdev->base + CIFR);
+
+	pcdev->active = list_first_entry(&pcdev->capture,
+					 struct pxa_buffer, vb.queue);
+	vb = &pcdev->active->vb;
+	buf = container_of(vb, struct pxa_buffer, vb);
+	pxa_videobuf_set_actdma(pcdev, buf);
+
+	pxa_dma_start_channels(pcdev);
+}
+
+static irqreturn_t pxa_camera_irq(int irq, void *data)
+{
+	struct pxa_camera_dev *pcdev = data;
+	unsigned long status, cicr0;
+
 	status = __raw_readl(pcdev->base + CISR);
 	dev_dbg(pcdev->soc_host.v4l2_dev.dev,
 		"Camera interrupt status 0x%lx\n", status);
@@ -939,20 +963,9 @@ static irqreturn_t pxa_camera_irq(int irq, void *data)
 	__raw_writel(status, pcdev->base + CISR);
 
 	if (status & CISR_EOF) {
-		/* Reset the FIFOs */
-		cifr = __raw_readl(pcdev->base + CIFR) | CIFR_RESET_F;
-		__raw_writel(cifr, pcdev->base + CIFR);
-
-		pcdev->active = list_first_entry(&pcdev->capture,
-					   struct pxa_buffer, vb.queue);
-		vb = &pcdev->active->vb;
-		buf = container_of(vb, struct pxa_buffer, vb);
-		pxa_videobuf_set_actdma(pcdev, buf);
-
-		pxa_dma_start_channels(pcdev);
-
 		cicr0 = __raw_readl(pcdev->base + CICR0) | CICR0_EOFM;
 		__raw_writel(cicr0, pcdev->base + CICR0);
+		tasklet_schedule(&pcdev->task_eof);
 	}
 
 	return IRQ_HANDLED;
@@ -1847,6 +1860,7 @@ static int pxa_camera_probe(struct platform_device *pdev)
 	pcdev->soc_host.priv		= pcdev;
 	pcdev->soc_host.v4l2_dev.dev	= &pdev->dev;
 	pcdev->soc_host.nr		= pdev->id;
+	tasklet_init(&pcdev->task_eof, pxa_camera_eof, (unsigned long)pcdev);
 
 	err = soc_camera_host_register(&pcdev->soc_host);
 	if (err)
-- 
2.1.4

[PATCH v3 3/4] media: pxa_camera: trivial move of dma irq functions

[Robert Jarzmik]

From: Robert Jarzmik <robert.jarzmik@intel.com>

This moves the dma irq handling functions up in the source file, so that
they are available before DMA preparation functions. It prepares the
conversion to DMA engine, where the descriptors are populated with these
functions as callbacks.

Signed-off-by: Robert Jarzmik <robert.jarzmik@intel.com>
---
Since v1: fixed prototypes change
---
 drivers/media/platform/soc_camera/pxa_camera.c | 42 +++++++++++++++-----------
 1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/drivers/media/platform/soc_camera/pxa_camera.c b/drivers/media/platform/soc_camera/pxa_camera.c
index 39c7e7519b3c..cdfb93aaee43 100644
--- a/drivers/media/platform/soc_camera/pxa_camera.c
+++ b/drivers/media/platform/soc_camera/pxa_camera.c
@@ -313,6 +313,30 @@ static int calculate_dma_sglen(struct scatterlist *sglist, int sglen,
 	return i + 1;
 }
 
+static void pxa_camera_dma_irq(struct pxa_camera_dev *pcdev,
+			       enum pxa_camera_active_dma act_dma);
+
+static void pxa_camera_dma_irq_y(int channel, void *data)
+{
+	struct pxa_camera_dev *pcdev = data;
+
+	pxa_camera_dma_irq(pcdev, DMA_Y);
+}
+
+static void pxa_camera_dma_irq_u(int channel, void *data)
+{
+	struct pxa_camera_dev *pcdev = data;
+
+	pxa_camera_dma_irq(pcdev, DMA_U);
+}
+
+static void pxa_camera_dma_irq_v(int channel, void *data)
+{
+	struct pxa_camera_dev *pcdev = data;
+
+	pxa_camera_dma_irq(pcdev, DMA_V);
+}
+
 /**
  * pxa_init_dma_channel - init dma descriptors
  * @pcdev: pxa camera device
@@ -810,24 +834,6 @@ out:
 	spin_unlock_irqrestore(&pcdev->lock, flags);
 }
 
-static void pxa_camera_dma_irq_y(int channel, void *data)
-{
-	struct pxa_camera_dev *pcdev = data;
-	pxa_camera_dma_irq(channel, pcdev, DMA_Y);
-}
-
-static void pxa_camera_dma_irq_u(int channel, void *data)
-{
-	struct pxa_camera_dev *pcdev = data;
-	pxa_camera_dma_irq(channel, pcdev, DMA_U);
-}
-
-static void pxa_camera_dma_irq_v(int channel, void *data)
-{
-	struct pxa_camera_dev *pcdev = data;
-	pxa_camera_dma_irq(channel, pcdev, DMA_V);
-}
-
 static struct videobuf_queue_ops pxa_videobuf_ops = {
 	.buf_setup      = pxa_videobuf_setup,
 	.buf_prepare    = pxa_videobuf_prepare,
-- 
2.1.4

[PATCH v3 4/4] media: pxa_camera: conversion to dmaengine

[Robert Jarzmik]

Convert pxa_camera to dmaengine. This removes all DMA registers
manipulation in favor of the more generic dmaengine API.

The functional level should be the same as before. The biggest change is
in the videobuf_sg_splice() function, which splits a videobuf-dma into
several scatterlists for 3 planes captures (Y, U, V).

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
Since v1: Guennadi's fixes
          dma tasklet functions prototypes change (trivial move)
Since v2: sglist cut revamped with Guennadi's comments
---
 drivers/media/platform/soc_camera/pxa_camera.c | 492 ++++++++++++++-----------
 1 file changed, 267 insertions(+), 225 deletions(-)

diff --git a/drivers/media/platform/soc_camera/pxa_camera.c b/drivers/media/platform/soc_camera/pxa_camera.c
index cdfb93aaee43..030ed7413bba 100644
--- a/drivers/media/platform/soc_camera/pxa_camera.c
+++ b/drivers/media/platform/soc_camera/pxa_camera.c
@@ -28,6 +28,9 @@
 #include <linux/clk.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dma/pxa-dma.h>
 
 #include <media/v4l2-common.h>
 #include <media/v4l2-dev.h>
@@ -38,7 +41,6 @@
 
 #include <linux/videodev2.h>
 
-#include <mach/dma.h>
 #include <linux/platform_data/camera-pxa.h>
 
 #define PXA_CAM_VERSION "0.0.6"
@@ -175,21 +177,16 @@ enum pxa_camera_active_dma {
 	DMA_V = 0x4,
 };
 
-/* descriptor needed for the PXA DMA engine */
-struct pxa_cam_dma {
-	dma_addr_t		sg_dma;
-	struct pxa_dma_desc	*sg_cpu;
-	size_t			sg_size;
-	int			sglen;
-};
-
 /* buffer for one video frame */
 struct pxa_buffer {
 	/* common v4l buffer stuff -- must be first */
 	struct videobuf_buffer		vb;
 	u32	code;
 	/* our descriptor lists for Y, U and V channels */
-	struct pxa_cam_dma		dmas[3];
+	struct dma_async_tx_descriptor	*descs[3];
+	dma_cookie_t			cookie[3];
+	struct scatterlist		*sg[3];
+	int				sg_len[3];
 	int				inwork;
 	enum pxa_camera_active_dma	active_dma;
 };
@@ -207,7 +204,7 @@ struct pxa_camera_dev {
 	void __iomem		*base;
 
 	int			channels;
-	unsigned int		dma_chans[3];
+	struct dma_chan		*dma_chans[3];
 
 	struct pxacamera_platform_data *pdata;
 	struct resource		*res;
@@ -222,7 +219,6 @@ struct pxa_camera_dev {
 	spinlock_t		lock;
 
 	struct pxa_buffer	*active;
-	struct pxa_dma_desc	*sg_tail[3];
 	struct tasklet_struct	task_eof;
 
 	u32			save_cicr[5];
@@ -259,7 +255,6 @@ static int pxa_videobuf_setup(struct videobuf_queue *vq, unsigned int *count,
 static void free_buffer(struct videobuf_queue *vq, struct pxa_buffer *buf)
 {
 	struct soc_camera_device *icd = vq->priv_data;
-	struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
 	struct videobuf_dmabuf *dma = videobuf_to_dma(&buf->vb);
 	int i;
 
@@ -276,61 +271,142 @@ static void free_buffer(struct videobuf_queue *vq, struct pxa_buffer *buf)
 	if (buf->vb.state == VIDEOBUF_NEEDS_INIT)
 		return;
 
-	for (i = 0; i < ARRAY_SIZE(buf->dmas); i++) {
-		if (buf->dmas[i].sg_cpu)
-			dma_free_coherent(ici->v4l2_dev.dev,
-					  buf->dmas[i].sg_size,
-					  buf->dmas[i].sg_cpu,
-					  buf->dmas[i].sg_dma);
-		buf->dmas[i].sg_cpu = NULL;
+	for (i = 0; i < 3 && buf->descs[i]; i++) {
+		async_tx_ack(buf->descs[i]);
+		kfree(buf->sg[i]);
+		buf->descs[i] = NULL;
+		buf->sg[i] = NULL;
+		buf->sg_len[i] = 0;
 	}
 	videobuf_dma_unmap(vq->dev, dma);
 	videobuf_dma_free(dma);
 
 	buf->vb.state = VIDEOBUF_NEEDS_INIT;
+
+	dev_dbg(icd->parent, "%s end (vb=0x%p) 0x%08lx %d\n", __func__,
+		&buf->vb, buf->vb.baddr, buf->vb.bsize);
 }
 
-static int calculate_dma_sglen(struct scatterlist *sglist, int sglen,
-			       int sg_first_ofs, int size)
+
+struct sg_splitter {
+	struct scatterlist *in_sg0;
+	int nents;
+	off_t skip_sg0;
+	size_t len_last_sg;
+	struct scatterlist *out_sg;
+};
+
+static struct sg_splitter *sg_calculate_split(struct scatterlist *in,
+					      off_t skip, const size_t *sizes,
+					      int nb_splits, gfp_t gfp_mask)
 {
-	int i, offset, dma_len, xfer_len;
+	int i;
+	size_t size = sizes[0], len;
+	struct sg_splitter *splitters, *curr;
 	struct scatterlist *sg;
 
-	offset = sg_first_ofs;
-	for_each_sg(sglist, sg, sglen, i) {
-		dma_len = sg_dma_len(sg);
+	splitters = kcalloc(nb_splits, sizeof(*splitters), gfp_mask);
+	if (!splitters)
+		return NULL;
+
+	curr = splitters;
+	for_each_sg(in, sg, sg_nents(in), i) {
+		if (skip > sg_dma_len(sg)) {
+			skip -= sg_dma_len(sg);
+			continue;
+		}
+		len = min_t(size_t, size, sg_dma_len(sg) - skip);
+		if (!curr->in_sg0) {
+			curr->in_sg0 = sg;
+			curr->skip_sg0 = sg_dma_len(sg) - len;
+		}
+		size -= len;
+		curr->nents++;
+		if (!size) {
+			curr->len_last_sg = len;
+			size = *(++sizes);
+
+			if (!--nb_splits)
+				break;
+
+			curr++;
+			if (len < sg_dma_len(sg) - skip) {
+				curr->in_sg0 = sg;
+				curr->skip_sg0 = sg_dma_len(sg) - skip - len;
+				curr->nents++;
+			}
+		}
+	}
+
+	return splitters;
+}
+
+static int sg_split(struct scatterlist *in, const int nb_splits,
+		    const size_t *split_sizes, struct scatterlist **out,
+		    gfp_t gfp_mask)
+{
+	int i, j;
+	struct scatterlist *in_sg, *out_sg;
+	struct sg_splitter *splitters, *split;
+
+	splitters = sg_calculate_split(in, 0, split_sizes, nb_splits, gfp_mask);
+	if (!splitters)
+		return -ENOMEM;
 
-		/* PXA27x Developer's Manual 27.4.4.1: round up to 8 bytes */
-		xfer_len = roundup(min(dma_len - offset, size), 8);
+	for (i = 0; i < nb_splits; i++) {
+		splitters[i].out_sg = kmalloc_array(splitters[i].nents,
+						    sizeof(struct scatterlist),
+						    gfp_mask);
+		if (!splitters[i].out_sg)
+			goto err;
+	}
 
-		size = max(0, size - xfer_len);
-		offset = 0;
-		if (size == 0)
-			break;
+	for (i = 0, split = splitters; i < nb_splits; i++, split++) {
+		in_sg = split->in_sg0;
+		out_sg = split->out_sg;
+		out[i] = out_sg;
+		for (j = 0; j < split->nents; j++, out_sg++) {
+			*out_sg = *in_sg;
+			if (!j) {
+				out_sg->offset = split->skip_sg0;
+				sg_dma_len(out_sg) -= split->skip_sg0;
+			} else {
+				out_sg->offset = 0;
+			}
+			in_sg = sg_next(in_sg);
+		}
+		sg_dma_len(--out_sg) = split->len_last_sg;
+		sg_mark_end(out_sg);
 	}
 
-	BUG_ON(size != 0);
-	return i + 1;
+	kfree(splitters);
+	return 0;
+
+err:
+	for (i = 0; i < nb_splits; i++)
+		kfree(splitters[i].out_sg);
+	kfree(splitters);
+	return -ENOMEM;
 }
 
 static void pxa_camera_dma_irq(struct pxa_camera_dev *pcdev,
 			       enum pxa_camera_active_dma act_dma);
 
-static void pxa_camera_dma_irq_y(int channel, void *data)
+static void pxa_camera_dma_irq_y(void *data)
 {
 	struct pxa_camera_dev *pcdev = data;
 
 	pxa_camera_dma_irq(pcdev, DMA_Y);
 }
 
-static void pxa_camera_dma_irq_u(int channel, void *data)
+static void pxa_camera_dma_irq_u(void *data)
 {
 	struct pxa_camera_dev *pcdev = data;
 
 	pxa_camera_dma_irq(pcdev, DMA_U);
 }
 
-static void pxa_camera_dma_irq_v(int channel, void *data)
+static void pxa_camera_dma_irq_v(void *data)
 {
 	struct pxa_camera_dev *pcdev = data;
 
@@ -345,93 +421,55 @@ static void pxa_camera_dma_irq_v(int channel, void *data)
  * @channel: dma channel (0 => 'Y', 1 => 'U', 2 => 'V')
  * @cibr: camera Receive Buffer Register
  * @size: bytes to transfer
- * @sg_first: first element of sg_list
- * @sg_first_ofs: offset in first element of sg_list
+ * @offset: offset in videobuffer of the first byte to transfer
  *
  * Prepares the pxa dma descriptors to transfer one camera channel.
- * Beware sg_first and sg_first_ofs are both input and output parameters.
  *
- * Returns 0 or -ENOMEM if no coherent memory is available
+ * Returns 0 if success or -ENOMEM if no memory is available
  */
 static int pxa_init_dma_channel(struct pxa_camera_dev *pcdev,
 				struct pxa_buffer *buf,
 				struct videobuf_dmabuf *dma, int channel,
-				int cibr, int size,
-				struct scatterlist **sg_first, int *sg_first_ofs)
+				int cibr, int size, int offset)
 {
-	struct pxa_cam_dma *pxa_dma = &buf->dmas[channel];
-	struct device *dev = pcdev->soc_host.v4l2_dev.dev;
-	struct scatterlist *sg;
-	int i, offset, sglen;
-	int dma_len = 0, xfer_len = 0;
-
-	if (pxa_dma->sg_cpu)
-		dma_free_coherent(dev, pxa_dma->sg_size,
-				  pxa_dma->sg_cpu, pxa_dma->sg_dma);
-
-	sglen = calculate_dma_sglen(*sg_first, dma->sglen,
-				    *sg_first_ofs, size);
-
-	pxa_dma->sg_size = (sglen + 1) * sizeof(struct pxa_dma_desc);
-	pxa_dma->sg_cpu = dma_alloc_coherent(dev, pxa_dma->sg_size,
-					     &pxa_dma->sg_dma, GFP_KERNEL);
-	if (!pxa_dma->sg_cpu)
-		return -ENOMEM;
-
-	pxa_dma->sglen = sglen;
-	offset = *sg_first_ofs;
-
-	dev_dbg(dev, "DMA: sg_first=%p, sglen=%d, ofs=%d, dma.desc=%x\n",
-		*sg_first, sglen, *sg_first_ofs, pxa_dma->sg_dma);
-
-
-	for_each_sg(*sg_first, sg, sglen, i) {
-		dma_len = sg_dma_len(sg);
-
-		/* PXA27x Developer's Manual 27.4.4.1: round up to 8 bytes */
-		xfer_len = roundup(min(dma_len - offset, size), 8);
-
-		size = max(0, size - xfer_len);
-
-		pxa_dma->sg_cpu[i].dsadr = pcdev->res->start + cibr;
-		pxa_dma->sg_cpu[i].dtadr = sg_dma_address(sg) + offset;
-		pxa_dma->sg_cpu[i].dcmd =
-			DCMD_FLOWSRC | DCMD_BURST8 | DCMD_INCTRGADDR | xfer_len;
-#ifdef DEBUG
-		if (!i)
-			pxa_dma->sg_cpu[i].dcmd |= DCMD_STARTIRQEN;
-#endif
-		pxa_dma->sg_cpu[i].ddadr =
-			pxa_dma->sg_dma + (i + 1) * sizeof(struct pxa_dma_desc);
-
-		dev_vdbg(dev, "DMA: desc.%08x->@phys=0x%08x, len=%d\n",
-			 pxa_dma->sg_dma + i * sizeof(struct pxa_dma_desc),
-			 sg_dma_address(sg) + offset, xfer_len);
-		offset = 0;
-
-		if (size == 0)
-			break;
+	struct dma_chan *dma_chan = pcdev->dma_chans[channel];
+	struct scatterlist *sg = buf->sg[channel];
+	int sglen;
+	struct dma_async_tx_descriptor *tx;
+
+	sglen = sg_nents(sg);
+	tx = dmaengine_prep_slave_sg(dma_chan, sg, sglen, DMA_DEV_TO_MEM,
+				     DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!tx) {
+		dev_err(pcdev->soc_host.v4l2_dev.dev,
+			"dmaengine_prep_slave_sg failed\n");
+		goto fail;
 	}
 
-	pxa_dma->sg_cpu[sglen].ddadr = DDADR_STOP;
-	pxa_dma->sg_cpu[sglen].dcmd  = DCMD_FLOWSRC | DCMD_BURST8 | DCMD_ENDIRQEN;
-
-	/*
-	 * Handle 1 special case :
-	 *  - in 3 planes (YUV422P format), we might finish with xfer_len equal
-	 *    to dma_len (end on PAGE boundary). In this case, the sg element
-	 *    for next plane should be the next after the last used to store the
-	 *    last scatter gather RAM page
-	 */
-	if (xfer_len >= dma_len) {
-		*sg_first_ofs = xfer_len - dma_len;
-		*sg_first = sg_next(sg);
-	} else {
-		*sg_first_ofs = xfer_len;
-		*sg_first = sg;
+	tx->callback_param = pcdev;
+	switch (channel) {
+	case 0:
+		tx->callback = pxa_camera_dma_irq_y;
+		break;
+	case 1:
+		tx->callback = pxa_camera_dma_irq_u;
+		break;
+	case 2:
+		tx->callback = pxa_camera_dma_irq_v;
+		break;
 	}
 
+	buf->descs[channel] = tx;
+	buf->sg_len[channel] = sglen;
 	return 0;
+fail:
+	kfree(sg);
+
+	dev_dbg(pcdev->soc_host.v4l2_dev.dev,
+		"%s (vb=0x%p) dma_tx=%p\n",
+		__func__, &buf->vb, tx);
+
+	return -ENOMEM;
 }
 
 static void pxa_videobuf_set_actdma(struct pxa_camera_dev *pcdev,
@@ -458,6 +496,7 @@ static int pxa_videobuf_prepare(struct videobuf_queue *vq,
 	struct pxa_buffer *buf = container_of(vb, struct pxa_buffer, vb);
 	int ret;
 	int size_y, size_u = 0, size_v = 0;
+	size_t sizes[3];
 
 	dev_dbg(dev, "%s (vb=0x%p) 0x%08lx %d\n", __func__,
 		vb, vb->baddr, vb->bsize);
@@ -500,9 +539,7 @@ static int pxa_videobuf_prepare(struct videobuf_queue *vq,
 
 	if (vb->state == VIDEOBUF_NEEDS_INIT) {
 		int size = vb->size;
-		int next_ofs = 0;
 		struct videobuf_dmabuf *dma = videobuf_to_dma(vb);
-		struct scatterlist *sg;
 
 		ret = videobuf_iolock(vq, vb, NULL);
 		if (ret)
@@ -515,11 +552,19 @@ static int pxa_videobuf_prepare(struct videobuf_queue *vq,
 			size_y = size;
 		}
 
-		sg = dma->sglist;
+		sizes[0] = size_y;
+		sizes[1] = size_u;
+		sizes[2] = size_v;
+		ret = sg_split(dma->sglist, pcdev->channels, sizes, buf->sg,
+			       GFP_KERNEL);
+		if (ret < 0) {
+			dev_err(dev, "sg_split failed: %d\n", ret);
+			goto fail;
+		}
 
 		/* init DMA for Y channel */
-		ret = pxa_init_dma_channel(pcdev, buf, dma, 0, CIBR0, size_y,
-					   &sg, &next_ofs);
+		ret = pxa_init_dma_channel(pcdev, buf, dma, 0, CIBR0,
+					   size_y, 0);
 		if (ret) {
 			dev_err(dev, "DMA initialization for Y/RGB failed\n");
 			goto fail;
@@ -528,19 +573,19 @@ static int pxa_videobuf_prepare(struct videobuf_queue *vq,
 		/* init DMA for U channel */
 		if (size_u)
 			ret = pxa_init_dma_channel(pcdev, buf, dma, 1, CIBR1,
-						   size_u, &sg, &next_ofs);
+						   size_u, size_y);
 		if (ret) {
 			dev_err(dev, "DMA initialization for U failed\n");
-			goto fail_u;
+			goto fail;
 		}
 
 		/* init DMA for V channel */
 		if (size_v)
 			ret = pxa_init_dma_channel(pcdev, buf, dma, 2, CIBR2,
-						   size_v, &sg, &next_ofs);
+						   size_v, size_y + size_u);
 		if (ret) {
 			dev_err(dev, "DMA initialization for V failed\n");
-			goto fail_v;
+			goto fail;
 		}
 
 		vb->state = VIDEOBUF_PREPARED;
@@ -551,12 +596,6 @@ static int pxa_videobuf_prepare(struct videobuf_queue *vq,
 
 	return 0;
 
-fail_v:
-	dma_free_coherent(dev, buf->dmas[1].sg_size,
-			  buf->dmas[1].sg_cpu, buf->dmas[1].sg_dma);
-fail_u:
-	dma_free_coherent(dev, buf->dmas[0].sg_size,
-			  buf->dmas[0].sg_cpu, buf->dmas[0].sg_dma);
 fail:
 	free_buffer(vq, buf);
 out:
@@ -580,10 +619,8 @@ static void pxa_dma_start_channels(struct pxa_camera_dev *pcdev)
 
 	for (i = 0; i < pcdev->channels; i++) {
 		dev_dbg(pcdev->soc_host.v4l2_dev.dev,
-			"%s (channel=%d) ddadr=%08x\n", __func__,
-			i, active->dmas[i].sg_dma);
-		DDADR(pcdev->dma_chans[i]) = active->dmas[i].sg_dma;
-		DCSR(pcdev->dma_chans[i]) = DCSR_RUN;
+			"%s (channel=%d)\n", __func__, i);
+		dma_async_issue_pending(pcdev->dma_chans[i]);
 	}
 }
 
@@ -594,7 +631,7 @@ static void pxa_dma_stop_channels(struct pxa_camera_dev *pcdev)
 	for (i = 0; i < pcdev->channels; i++) {
 		dev_dbg(pcdev->soc_host.v4l2_dev.dev,
 			"%s (channel=%d)\n", __func__, i);
-		DCSR(pcdev->dma_chans[i]) = 0;
+		dmaengine_terminate_all(pcdev->dma_chans[i]);
 	}
 }
 
@@ -602,18 +639,12 @@ static void pxa_dma_add_tail_buf(struct pxa_camera_dev *pcdev,
 				 struct pxa_buffer *buf)
 {
 	int i;
-	struct pxa_dma_desc *buf_last_desc;
 
 	for (i = 0; i < pcdev->channels; i++) {
-		buf_last_desc = buf->dmas[i].sg_cpu + buf->dmas[i].sglen;
-		buf_last_desc->ddadr = DDADR_STOP;
-
-		if (pcdev->sg_tail[i])
-			/* Link the new buffer to the old tail */
-			pcdev->sg_tail[i]->ddadr = buf->dmas[i].sg_dma;
-
-		/* Update the channel tail */
-		pcdev->sg_tail[i] = buf_last_desc;
+		buf->cookie[i] = dmaengine_submit(buf->descs[i]);
+		dev_dbg(pcdev->soc_host.v4l2_dev.dev,
+			"%s (channel=%d) : submit vb=%p cookie=%d\n",
+			__func__, i, buf, buf->descs[i]->cookie);
 	}
 }
 
@@ -705,8 +736,6 @@ static void pxa_camera_wakeup(struct pxa_camera_dev *pcdev,
 			      struct videobuf_buffer *vb,
 			      struct pxa_buffer *buf)
 {
-	int i;
-
 	/* _init is used to debug races, see comment in pxa_camera_reqbufs() */
 	list_del_init(&vb->queue);
 	vb->state = VIDEOBUF_DONE;
@@ -718,8 +747,6 @@ static void pxa_camera_wakeup(struct pxa_camera_dev *pcdev,
 
 	if (list_empty(&pcdev->capture)) {
 		pxa_camera_stop_capture(pcdev);
-		for (i = 0; i < pcdev->channels; i++)
-			pcdev->sg_tail[i] = NULL;
 		return;
 	}
 
@@ -743,50 +770,41 @@ static void pxa_camera_wakeup(struct pxa_camera_dev *pcdev,
  *
  * Context: should only be called within the dma irq handler
  */
-static void pxa_camera_check_link_miss(struct pxa_camera_dev *pcdev)
+static void pxa_camera_check_link_miss(struct pxa_camera_dev *pcdev,
+				       dma_cookie_t last_submitted,
+				       dma_cookie_t last_issued)
 {
-	int i, is_dma_stopped = 1;
+	int is_dma_stopped;
 
-	for (i = 0; i < pcdev->channels; i++)
-		if (DDADR(pcdev->dma_chans[i]) != DDADR_STOP)
-			is_dma_stopped = 0;
+	is_dma_stopped = (last_submitted != last_issued);
 	dev_dbg(pcdev->soc_host.v4l2_dev.dev,
-		"%s : top queued buffer=%p, dma_stopped=%d\n",
+		"%s : top queued buffer=%p, is_dma_stopped=%d\n",
 		__func__, pcdev->active, is_dma_stopped);
 	if (pcdev->active && is_dma_stopped)
 		pxa_camera_start_capture(pcdev);
 }
 
-static void pxa_camera_dma_irq(int channel, struct pxa_camera_dev *pcdev,
+static void pxa_camera_dma_irq(struct pxa_camera_dev *pcdev,
 			       enum pxa_camera_active_dma act_dma)
 {
 	struct device *dev = pcdev->soc_host.v4l2_dev.dev;
-	struct pxa_buffer *buf;
+	struct pxa_buffer *buf, *last_buf;
 	unsigned long flags;
-	u32 status, camera_status, overrun;
+	u32 camera_status, overrun;
+	int chan;
 	struct videobuf_buffer *vb;
+	enum dma_status last_status;
+	dma_cookie_t last_issued;
 
 	spin_lock_irqsave(&pcdev->lock, flags);
 
-	status = DCSR(channel);
-	DCSR(channel) = status;
-
 	camera_status = __raw_readl(pcdev->base + CISR);
+	dev_dbg(dev, "camera dma irq, cisr=0x%x dma=%d\n",
+		camera_status, act_dma);
 	overrun = CISR_IFO_0;
 	if (pcdev->channels == 3)
 		overrun |= CISR_IFO_1 | CISR_IFO_2;
 
-	if (status & DCSR_BUSERR) {
-		dev_err(dev, "DMA Bus Error IRQ!\n");
-		goto out;
-	}
-
-	if (!(status & (DCSR_ENDINTR | DCSR_STARTINTR))) {
-		dev_err(dev, "Unknown DMA IRQ source, status: 0x%08x\n",
-			status);
-		goto out;
-	}
-
 	/*
 	 * pcdev->active should not be NULL in DMA irq handler.
 	 *
@@ -806,28 +824,41 @@ static void pxa_camera_dma_irq(int channel, struct pxa_camera_dev *pcdev,
 	buf = container_of(vb, struct pxa_buffer, vb);
 	WARN_ON(buf->inwork || list_empty(&vb->queue));
 
-	dev_dbg(dev, "%s channel=%d %s%s(vb=0x%p) dma.desc=%x\n",
-		__func__, channel, status & DCSR_STARTINTR ? "SOF " : "",
-		status & DCSR_ENDINTR ? "EOF " : "", vb, DDADR(channel));
-
-	if (status & DCSR_ENDINTR) {
-		/*
-		 * It's normal if the last frame creates an overrun, as there
-		 * are no more DMA descriptors to fetch from QCI fifos
-		 */
-		if (camera_status & overrun &&
-		    !list_is_last(pcdev->capture.next, &pcdev->capture)) {
-			dev_dbg(dev, "FIFO overrun! CISR: %x\n",
-				camera_status);
-			pxa_camera_stop_capture(pcdev);
-			pxa_camera_start_capture(pcdev);
-			goto out;
-		}
-		buf->active_dma &= ~act_dma;
-		if (!buf->active_dma) {
-			pxa_camera_wakeup(pcdev, vb, buf);
-			pxa_camera_check_link_miss(pcdev);
-		}
+	/*
+	 * It's normal if the last frame creates an overrun, as there
+	 * are no more DMA descriptors to fetch from QCI fifos
+	 */
+	switch (act_dma) {
+	case DMA_U:
+		chan = 1;
+		break;
+	case DMA_V:
+		chan = 2;
+		break;
+	default:
+		chan = 0;
+		break;
+	}
+	last_buf = list_entry(pcdev->capture.prev,
+			      struct pxa_buffer, vb.queue);
+	last_status = dma_async_is_tx_complete(pcdev->dma_chans[chan],
+					       last_buf->cookie[chan],
+					       NULL, &last_issued);
+	if (camera_status & overrun &&
+	    last_status != DMA_COMPLETE) {
+		dev_dbg(dev, "FIFO overrun! CISR: %x\n",
+			camera_status);
+		pxa_camera_stop_capture(pcdev);
+		list_for_each_entry(buf, &pcdev->capture, vb.queue)
+			pxa_dma_add_tail_buf(pcdev, buf);
+		pxa_camera_start_capture(pcdev);
+		goto out;
+	}
+	buf->active_dma &= ~act_dma;
+	if (!buf->active_dma) {
+		pxa_camera_wakeup(pcdev, vb, buf);
+		pxa_camera_check_link_miss(pcdev, last_buf->cookie[chan],
+					   last_issued);
 	}
 
 out:
@@ -1014,10 +1045,7 @@ static void pxa_camera_clock_stop(struct soc_camera_host *ici)
 	__raw_writel(0x3ff, pcdev->base + CICR0);
 
 	/* Stop DMA engine */
-	DCSR(pcdev->dma_chans[0]) = 0;
-	DCSR(pcdev->dma_chans[1]) = 0;
-	DCSR(pcdev->dma_chans[2]) = 0;
-
+	pxa_dma_stop_channels(pcdev);
 	pxa_camera_deactivate(pcdev);
 }
 
@@ -1644,10 +1672,6 @@ static int pxa_camera_resume(struct device *dev)
 	struct pxa_camera_dev *pcdev = ici->priv;
 	int i = 0, ret = 0;
 
-	DRCMR(68) = pcdev->dma_chans[0] | DRCMR_MAPVLD;
-	DRCMR(69) = pcdev->dma_chans[1] | DRCMR_MAPVLD;
-	DRCMR(70) = pcdev->dma_chans[2] | DRCMR_MAPVLD;
-
 	__raw_writel(pcdev->save_cicr[i++] & ~CICR0_ENB, pcdev->base + CICR0);
 	__raw_writel(pcdev->save_cicr[i++], pcdev->base + CICR1);
 	__raw_writel(pcdev->save_cicr[i++], pcdev->base + CICR2);
@@ -1753,8 +1777,11 @@ static int pxa_camera_probe(struct platform_device *pdev)
 	struct pxa_camera_dev *pcdev;
 	struct resource *res;
 	void __iomem *base;
+	struct dma_slave_config config;
+	dma_cap_mask_t mask;
+	struct pxad_param params;
 	int irq;
-	int err = 0;
+	int err = 0, i;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	irq = platform_get_irq(pdev, 0);
@@ -1822,36 +1849,51 @@ static int pxa_camera_probe(struct platform_device *pdev)
 	pcdev->base = base;
 
 	/* request dma */
-	err = pxa_request_dma("CI_Y", DMA_PRIO_HIGH,
-			      pxa_camera_dma_irq_y, pcdev);
-	if (err < 0) {
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+	dma_cap_set(DMA_PRIVATE, mask);
+
+	params.prio = 0;
+	params.drcmr = 68;
+	pcdev->dma_chans[0] =
+		dma_request_slave_channel_compat(mask, pxad_filter_fn,
+						 &params, &pdev->dev, "CI_Y");
+	if (!pcdev->dma_chans[0]) {
 		dev_err(&pdev->dev, "Can't request DMA for Y\n");
-		return err;
+		return -ENODEV;
 	}
-	pcdev->dma_chans[0] = err;
-	dev_dbg(&pdev->dev, "got DMA channel %d\n", pcdev->dma_chans[0]);
 
-	err = pxa_request_dma("CI_U", DMA_PRIO_HIGH,
-			      pxa_camera_dma_irq_u, pcdev);
-	if (err < 0) {
-		dev_err(&pdev->dev, "Can't request DMA for U\n");
+	params.drcmr = 69;
+	pcdev->dma_chans[1] =
+		dma_request_slave_channel_compat(mask, pxad_filter_fn,
+						 &params, &pdev->dev, "CI_U");
+	if (!pcdev->dma_chans[1]) {
+		dev_err(&pdev->dev, "Can't request DMA for Y\n");
 		goto exit_free_dma_y;
 	}
-	pcdev->dma_chans[1] = err;
-	dev_dbg(&pdev->dev, "got DMA channel (U) %d\n", pcdev->dma_chans[1]);
 
-	err = pxa_request_dma("CI_V", DMA_PRIO_HIGH,
-			      pxa_camera_dma_irq_v, pcdev);
-	if (err < 0) {
+	params.drcmr = 70;
+	pcdev->dma_chans[2] =
+		dma_request_slave_channel_compat(mask, pxad_filter_fn,
+						 &params, &pdev->dev, "CI_V");
+	if (!pcdev->dma_chans[2]) {
 		dev_err(&pdev->dev, "Can't request DMA for V\n");
 		goto exit_free_dma_u;
 	}
-	pcdev->dma_chans[2] = err;
-	dev_dbg(&pdev->dev, "got DMA channel (V) %d\n", pcdev->dma_chans[2]);
 
-	DRCMR(68) = pcdev->dma_chans[0] | DRCMR_MAPVLD;
-	DRCMR(69) = pcdev->dma_chans[1] | DRCMR_MAPVLD;
-	DRCMR(70) = pcdev->dma_chans[2] | DRCMR_MAPVLD;
+	memset(&config, 0, sizeof(config));
+	config.src_addr_width = 0;
+	config.src_maxburst = 8;
+	config.direction = DMA_DEV_TO_MEM;
+	for (i = 0; i < 3; i++) {
+		config.src_addr = pcdev->res->start + CIBR0 + i * 8;
+		err = dmaengine_slave_config(pcdev->dma_chans[i], &config);
+		if (err < 0) {
+			dev_err(&pdev->dev, "dma slave config failed: %d\n",
+				err);
+			goto exit_free_dma;
+		}
+	}
 
 	/* request irq */
 	err = devm_request_irq(&pdev->dev, pcdev->irq, pxa_camera_irq, 0,
@@ -1875,11 +1917,11 @@ static int pxa_camera_probe(struct platform_device *pdev)
 	return 0;
 
 exit_free_dma:
-	pxa_free_dma(pcdev->dma_chans[2]);
+	dma_release_channel(pcdev->dma_chans[2]);
 exit_free_dma_u:
-	pxa_free_dma(pcdev->dma_chans[1]);
+	dma_release_channel(pcdev->dma_chans[1]);
 exit_free_dma_y:
-	pxa_free_dma(pcdev->dma_chans[0]);
+	dma_release_channel(pcdev->dma_chans[0]);
 	return err;
 }
 
@@ -1889,9 +1931,9 @@ static int pxa_camera_remove(struct platform_device *pdev)
 	struct pxa_camera_dev *pcdev = container_of(soc_host,
 					struct pxa_camera_dev, soc_host);
 
-	pxa_free_dma(pcdev->dma_chans[0]);
-	pxa_free_dma(pcdev->dma_chans[1]);
-	pxa_free_dma(pcdev->dma_chans[2]);
+	dma_release_channel(pcdev->dma_chans[0]);
+	dma_release_channel(pcdev->dma_chans[1]);
+	dma_release_channel(pcdev->dma_chans[2]);
 
 	soc_camera_host_unregister(soc_host);
 
-- 
2.1.4

Re: [PATCH v3 3/4] media: pxa_camera: trivial move of dma irq functions

[Guennadi Liakhovetski]

On Wed, 29 Jul 2015, Robert Jarzmik wrote:

> From: Robert Jarzmik <robert.jarzmik@intel.com>
> 
> This moves the dma irq handling functions up in the source file, so that
> they are available before DMA preparation functions. It prepares the
> conversion to DMA engine, where the descriptors are populated with these
> functions as callbacks.
> 
> Signed-off-by: Robert Jarzmik <robert.jarzmik@intel.com>
> ---
> Since v1: fixed prototypes change
> ---
>  drivers/media/platform/soc_camera/pxa_camera.c | 42 +++++++++++++++-----------
>  1 file changed, 24 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/media/platform/soc_camera/pxa_camera.c b/drivers/media/platform/soc_camera/pxa_camera.c
> index 39c7e7519b3c..cdfb93aaee43 100644
> --- a/drivers/media/platform/soc_camera/pxa_camera.c
> +++ b/drivers/media/platform/soc_camera/pxa_camera.c
> @@ -313,6 +313,30 @@ static int calculate_dma_sglen(struct scatterlist *sglist, int sglen,

[snip]

> +	pxa_camera_dma_irq(pcdev, DMA_Y);

[snip]

> -	pxa_camera_dma_irq(channel, pcdev, DMA_Y);

This still seems to break compilation to me. Could you compile-test after 
each your patch, please?

Thanks
Guennadi

Re: [PATCH v3 4/4] media: pxa_camera: conversion to dmaengine

[Guennadi Liakhovetski]

Hi Robert,

I assume, the next iteration of your patches won't contain a local copy of 
the SG splitting code.

On Wed, 29 Jul 2015, Robert Jarzmik wrote:

> Convert pxa_camera to dmaengine. This removes all DMA registers
> manipulation in favor of the more generic dmaengine API.
> 
> The functional level should be the same as before. The biggest change is
> in the videobuf_sg_splice() function, which splits a videobuf-dma into
> several scatterlists for 3 planes captures (Y, U, V).
> 
> Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
> ---
> Since v1: Guennadi's fixes
>           dma tasklet functions prototypes change (trivial move)
> Since v2: sglist cut revamped with Guennadi's comments
> ---
>  drivers/media/platform/soc_camera/pxa_camera.c | 492 ++++++++++++++-----------
>  1 file changed, 267 insertions(+), 225 deletions(-)
> 
> diff --git a/drivers/media/platform/soc_camera/pxa_camera.c b/drivers/media/platform/soc_camera/pxa_camera.c
> index cdfb93aaee43..030ed7413bba 100644
> --- a/drivers/media/platform/soc_camera/pxa_camera.c
> +++ b/drivers/media/platform/soc_camera/pxa_camera.c

[snip]

> @@ -806,28 +824,41 @@ static void pxa_camera_dma_irq(int channel, struct pxa_camera_dev *pcdev,
>  	buf = container_of(vb, struct pxa_buffer, vb);
>  	WARN_ON(buf->inwork || list_empty(&vb->queue));
>  
> -	dev_dbg(dev, "%s channel=%d %s%s(vb=0x%p) dma.desc=%x\n",
> -		__func__, channel, status & DCSR_STARTINTR ? "SOF " : "",
> -		status & DCSR_ENDINTR ? "EOF " : "", vb, DDADR(channel));
> -
> -	if (status & DCSR_ENDINTR) {
> -		/*
> -		 * It's normal if the last frame creates an overrun, as there
> -		 * are no more DMA descriptors to fetch from QCI fifos
> -		 */
> -		if (camera_status & overrun &&
> -		    !list_is_last(pcdev->capture.next, &pcdev->capture)) {
> -			dev_dbg(dev, "FIFO overrun! CISR: %x\n",
> -				camera_status);
> -			pxa_camera_stop_capture(pcdev);
> -			pxa_camera_start_capture(pcdev);
> -			goto out;
> -		}
> -		buf->active_dma &= ~act_dma;
> -		if (!buf->active_dma) {
> -			pxa_camera_wakeup(pcdev, vb, buf);
> -			pxa_camera_check_link_miss(pcdev);
> -		}
> +	/*
> +	 * It's normal if the last frame creates an overrun, as there
> +	 * are no more DMA descriptors to fetch from QCI fifos
> +	 */
> +	switch (act_dma) {
> +	case DMA_U:
> +		chan = 1;
> +		break;
> +	case DMA_V:
> +		chan = 2;
> +		break;
> +	default:
> +		chan = 0;
> +		break;
> +	}
> +	last_buf = list_entry(pcdev->capture.prev,
> +			      struct pxa_buffer, vb.queue);

You can use list_last_entry()

> +	last_status = dma_async_is_tx_complete(pcdev->dma_chans[chan],
> +					       last_buf->cookie[chan],
> +					       NULL, &last_issued);
> +	if (camera_status & overrun &&
> +	    last_status != DMA_COMPLETE) {
> +		dev_dbg(dev, "FIFO overrun! CISR: %x\n",
> +			camera_status);
> +		pxa_camera_stop_capture(pcdev);
> +		list_for_each_entry(buf, &pcdev->capture, vb.queue)
> +			pxa_dma_add_tail_buf(pcdev, buf);

Why have you added this loop? Is it a bug in the current implementation or 
is it only needed with the switch to dmaengine?

> +		pxa_camera_start_capture(pcdev);
> +		goto out;
> +	}
> +	buf->active_dma &= ~act_dma;
> +	if (!buf->active_dma) {
> +		pxa_camera_wakeup(pcdev, vb, buf);
> +		pxa_camera_check_link_miss(pcdev, last_buf->cookie[chan],
> +					   last_issued);
>  	}
>  
>  out:
> @@ -1014,10 +1045,7 @@ static void pxa_camera_clock_stop(struct soc_camera_host *ici)
>  	__raw_writel(0x3ff, pcdev->base + CICR0);
>  
>  	/* Stop DMA engine */
> -	DCSR(pcdev->dma_chans[0]) = 0;
> -	DCSR(pcdev->dma_chans[1]) = 0;
> -	DCSR(pcdev->dma_chans[2]) = 0;
> -
> +	pxa_dma_stop_channels(pcdev);
>  	pxa_camera_deactivate(pcdev);
>  }
>  
> 

Thanks
Guennadi

Re: [PATCH v3 3/4] media: pxa_camera: trivial move of dma irq functions

[Robert Jarzmik]

Guennadi Liakhovetski <g.liakhovetski@gmx.de> writes:

> This still seems to break compilation to me. Could you compile-test after 
> each your patch, please?
Ah yes. Ill timing, I had sent the v4 before having these comments, so I'll have
to fix it in v5.

Cheers.

-- 
Robert

Re: [PATCH v3 4/4] media: pxa_camera: conversion to dmaengine

[Robert Jarzmik]

Guennadi Liakhovetski <g.liakhovetski@gmx.de> writes:

>> +	last_buf = list_entry(pcdev->capture.prev,
>> +			      struct pxa_buffer, vb.queue);
>
> You can use list_last_entry()
Ok.

>> +	last_status = dma_async_is_tx_complete(pcdev->dma_chans[chan],
>> +					       last_buf->cookie[chan],
>> +					       NULL, &last_issued);
>> +	if (camera_status & overrun &&
>> +	    last_status != DMA_COMPLETE) {
>> +		dev_dbg(dev, "FIFO overrun! CISR: %x\n",
>> +			camera_status);
>> +		pxa_camera_stop_capture(pcdev);
>> +		list_for_each_entry(buf, &pcdev->capture, vb.queue)
>> +			pxa_dma_add_tail_buf(pcdev, buf);
>
> Why have you added this loop? Is it a bug in the current implementation or 
> is it only needed with the switch to dmaengine?
It's a consequence of the switch.

With dmaengine, a dmaengine_terminate_all() removes all queued txs. It is
therefore necessary to requeue them. In the previous implementation, the
chaining was still good, and it was "enough" to just queue the first
videobuffer : the other buffers would follow by chaining.

Cheers.

-- 
Robert