[PATCH 0/2] i.MX3: support multi-size buffers in V4L

[PATCH 0/2] i.MX3: support multi-size buffers in V4L

[Guennadi Liakhovetski]

Supporting new V4L2 ioctl()s in the mx3_camera driver also requires an 
extension for the ipu-idmac dmaengine driver. The original thread, adding 
the ioctl()s can be found here:

http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/37143

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/

[PATCH 1/2] dmaengine: ipu-idmac: add support for the DMA_PAUSE control

[Guennadi Liakhovetski]

To support multi-size buffers in the mx3_camera V4L2 driver we have to be
able to stop DMA on a channel without releasing descriptors and completely
halting the hardware. Use the DMA_PAUSE control to implement this mode.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---
 drivers/dma/ipu/ipu_idmac.c |   65 +++++++++++++++++++++++++++---------------
 1 files changed, 42 insertions(+), 23 deletions(-)

diff --git a/drivers/dma/ipu/ipu_idmac.c b/drivers/dma/ipu/ipu_idmac.c
index c1a125e..42cdf1c 100644
--- a/drivers/dma/ipu/ipu_idmac.c
+++ b/drivers/dma/ipu/ipu_idmac.c
@@ -1306,6 +1306,7 @@ static irqreturn_t idmac_interrupt(int irq, void *dev_id)
 	    ipu_submit_buffer(ichan, descnew, sgnew, ichan->active_buffer) < 0) {
 		callback = descnew->txd.callback;
 		callback_param = descnew->txd.callback_param;
+		list_del_init(&descnew->list);
 		spin_unlock(&ichan->lock);
 		if (callback)
 			callback(callback_param);
@@ -1427,39 +1428,58 @@ static int __idmac_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
 {
 	struct idmac_channel *ichan = to_idmac_chan(chan);
 	struct idmac *idmac = to_idmac(chan->device);
+	struct ipu *ipu = to_ipu(idmac);
+	struct list_head *list, *tmp;
 	unsigned long flags;
 	int i;
 
-	/* Only supports DMA_TERMINATE_ALL */
-	if (cmd != DMA_TERMINATE_ALL)
-		return -ENXIO;
+	switch (cmd) {
+	case DMA_PAUSE:
+		spin_lock_irqsave(&ipu->lock, flags);
+		ipu_ic_disable_task(ipu, chan->chan_id);
 
-	ipu_disable_channel(idmac, ichan,
-			    ichan->status >= IPU_CHANNEL_ENABLED);
+		/* Return all descriptors into "prepared" state */
+		list_for_each_safe(list, tmp, &ichan->queue)
+			list_del_init(list);
 
-	tasklet_disable(&to_ipu(idmac)->tasklet);
+		ichan->sg[0] = NULL;
+		ichan->sg[1] = NULL;
 
-	/* ichan->queue is modified in ISR, have to spinlock */
-	spin_lock_irqsave(&ichan->lock, flags);
-	list_splice_init(&ichan->queue, &ichan->free_list);
+		spin_unlock_irqrestore(&ipu->lock, flags);
 
-	if (ichan->desc)
-		for (i = 0; i < ichan->n_tx_desc; i++) {
-			struct idmac_tx_desc *desc = ichan->desc + i;
-			if (list_empty(&desc->list))
-				/* Descriptor was prepared, but not submitted */
-				list_add(&desc->list, &ichan->free_list);
+		ichan->status = IPU_CHANNEL_INITIALIZED;
+		break;
+	case DMA_TERMINATE_ALL:
+		ipu_disable_channel(idmac, ichan,
+				    ichan->status >= IPU_CHANNEL_ENABLED);
 
-			async_tx_clear_ack(&desc->txd);
-		}
+		tasklet_disable(&ipu->tasklet);
 
-	ichan->sg[0] = NULL;
-	ichan->sg[1] = NULL;
-	spin_unlock_irqrestore(&ichan->lock, flags);
+		/* ichan->queue is modified in ISR, have to spinlock */
+		spin_lock_irqsave(&ichan->lock, flags);
+		list_splice_init(&ichan->queue, &ichan->free_list);
 
-	tasklet_enable(&to_ipu(idmac)->tasklet);
+		if (ichan->desc)
+			for (i = 0; i < ichan->n_tx_desc; i++) {
+				struct idmac_tx_desc *desc = ichan->desc + i;
+				if (list_empty(&desc->list))
+					/* Descriptor was prepared, but not submitted */
+					list_add(&desc->list, &ichan->free_list);
 
-	ichan->status = IPU_CHANNEL_INITIALIZED;
+				async_tx_clear_ack(&desc->txd);
+			}
+
+		ichan->sg[0] = NULL;
+		ichan->sg[1] = NULL;
+		spin_unlock_irqrestore(&ichan->lock, flags);
+
+		tasklet_enable(&ipu->tasklet);
+
+		ichan->status = IPU_CHANNEL_INITIALIZED;
+		break;
+	default:
+		return -ENOSYS;
+	}
 
 	return 0;
 }
@@ -1662,7 +1682,6 @@ static void __exit ipu_idmac_exit(struct ipu *ipu)
 		struct idmac_channel *ichan = ipu->channel + i;
 
 		idmac_control(&ichan->dma_chan, DMA_TERMINATE_ALL, 0);
-		idmac_prep_slave_sg(&ichan->dma_chan, NULL, 0, DMA_NONE, 0);
 	}
 
 	dma_async_device_unregister(&idmac->dma);
-- 
1.7.2.5

[PATCH 2/2] V4L: mx3-camera: prepare to support multi-size buffers

[Guennadi Liakhovetski]

Prepare the mx3_camera friver to support the new VIDIOC_CREATE_BUFS and
VIDIOC_PREPARE_BUF ioctl()s. The .queue_setup() vb2 operation must be
able to handle buffer sizes, provided by the caller, and the
.buf_prepare() operation must not use the currently configured frame
format for its operation, which makes it superfluous for this driver.
Its functionality is moved into .buf_queue().

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
---
 drivers/media/video/mx3_camera.c |  153 +++++++++++++++++++------------------
 1 files changed, 79 insertions(+), 74 deletions(-)

diff --git a/drivers/media/video/mx3_camera.c b/drivers/media/video/mx3_camera.c
index 6bfbce9..51eee4e 100644
--- a/drivers/media/video/mx3_camera.c
+++ b/drivers/media/video/mx3_camera.c
@@ -114,6 +114,7 @@ struct mx3_camera_dev {
 	struct list_head	capture;
 	spinlock_t		lock;		/* Protects video buffer lists */
 	struct mx3_camera_buffer *active;
+	size_t			buf_total;
 	struct vb2_alloc_ctx	*alloc_ctx;
 	enum v4l2_field		field;
 	int			sequence;
@@ -198,118 +199,117 @@ static int mx3_videobuf_setup(struct vb2_queue *vq,
 	struct soc_camera_device *icd = soc_camera_from_vb2q(vq);
 	struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
 	struct mx3_camera_dev *mx3_cam = ici->priv;
-	int bytes_per_line = soc_mbus_bytes_per_line(icd->user_width,
-						icd->current_fmt->host_fmt);
+	int bytes_per_line;
+	unsigned int height;
 
+	if (!mx3_cam->idmac_channel[0])
+		return -EINVAL;
+
+	if (fmt) {
+		const struct soc_camera_format_xlate *xlate = soc_camera_xlate_by_fourcc(icd,
+								fmt->fmt.pix.pixelformat);
+		bytes_per_line = soc_mbus_bytes_per_line(fmt->fmt.pix.width,
+							 xlate->host_fmt);
+		height = fmt->fmt.pix.height;
+	} else {
+		/* Called from VIDIOC_REQBUFS or in compatibility mode */
+		bytes_per_line = soc_mbus_bytes_per_line(icd->user_width,
+						icd->current_fmt->host_fmt);
+		height = icd->user_height;
+	}
 	if (bytes_per_line < 0)
 		return bytes_per_line;
 
-	if (!mx3_cam->idmac_channel[0])
-		return -EINVAL;
+	sizes[0] = bytes_per_line * height;
 
 	*num_planes = 1;
 
-	mx3_cam->sequence = 0;
-	sizes[0] = bytes_per_line * icd->user_height;
 	alloc_ctxs[0] = mx3_cam->alloc_ctx;
 
+	if (!vq->num_buffers)
+		mx3_cam->sequence = 0;
+
 	if (!*count)
 		*count = 32;
 
-	if (sizes[0] * *count > MAX_VIDEO_MEM * 1024 * 1024)
-		*count = MAX_VIDEO_MEM * 1024 * 1024 / sizes[0];
+	if (sizes[0] * *count + mx3_cam->buf_total > MAX_VIDEO_MEM * 1024 * 1024)
+		*count = (MAX_VIDEO_MEM * 1024 * 1024 - mx3_cam->buf_total) /
+			sizes[0];
 
 	return 0;
 }
 
-static int mx3_videobuf_prepare(struct vb2_buffer *vb)
+static enum pixel_fmt fourcc_to_ipu_pix(__u32 fourcc)
+{
+	/* Add more formats as need arises and test possibilities appear... */
+	switch (fourcc) {
+	case V4L2_PIX_FMT_RGB24:
+		return IPU_PIX_FMT_RGB24;
+	case V4L2_PIX_FMT_UYVY:
+	case V4L2_PIX_FMT_RGB565:
+	default:
+		return IPU_PIX_FMT_GENERIC;
+	}
+}
+
+static void mx3_videobuf_queue(struct vb2_buffer *vb)
 {
 	struct soc_camera_device *icd = soc_camera_from_vb2q(vb->vb2_queue);
 	struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
 	struct mx3_camera_dev *mx3_cam = ici->priv;
+	struct mx3_camera_buffer *buf = to_mx3_vb(vb);
+	struct scatterlist *sg = &buf->sg;
+	struct dma_async_tx_descriptor *txd;
 	struct idmac_channel *ichan = mx3_cam->idmac_channel[0];
-	struct scatterlist *sg;
-	struct mx3_camera_buffer *buf;
+	struct idmac_video_param *video = &ichan->params.video;
+	const struct soc_mbus_pixelfmt *host_fmt = icd->current_fmt->host_fmt;
+	int bytes_per_line = soc_mbus_bytes_per_line(icd->user_width, host_fmt);
+	unsigned long flags;
+	dma_cookie_t cookie;
 	size_t new_size;
-	int bytes_per_line = soc_mbus_bytes_per_line(icd->user_width,
-						icd->current_fmt->host_fmt);
-
-	if (bytes_per_line < 0)
-		return bytes_per_line;
 
-	buf = to_mx3_vb(vb);
-	sg = &buf->sg;
+	BUG_ON(bytes_per_line <= 0);
 
 	new_size = bytes_per_line * icd->user_height;
 
 	if (vb2_plane_size(vb, 0) < new_size) {
-		dev_err(icd->parent, "Buffer too small (%lu < %zu)\n",
-			vb2_plane_size(vb, 0), new_size);
-		return -ENOBUFS;
+		dev_err(icd->parent, "Buffer #%d too small (%lu < %zu)\n",
+			vb->v4l2_buf.index, vb2_plane_size(vb, 0), new_size);
+		goto error;
 	}
 
 	if (buf->state == CSI_BUF_NEEDS_INIT) {
 		sg_dma_address(sg)	= vb2_dma_contig_plane_paddr(vb, 0);
 		sg_dma_len(sg)		= new_size;
 
-		buf->txd = ichan->dma_chan.device->device_prep_slave_sg(
+		txd = ichan->dma_chan.device->device_prep_slave_sg(
 			&ichan->dma_chan, sg, 1, DMA_FROM_DEVICE,
 			DMA_PREP_INTERRUPT);
-		if (!buf->txd)
-			return -EIO;
+		if (!txd)
+			goto error;
 
-		buf->txd->callback_param	= buf->txd;
-		buf->txd->callback		= mx3_cam_dma_done;
+		txd->callback_param	= txd;
+		txd->callback		= mx3_cam_dma_done;
 
-		buf->state = CSI_BUF_PREPARED;
+		buf->state		= CSI_BUF_PREPARED;
+		buf->txd		= txd;
+	} else {
+		txd = buf->txd;
 	}
 
 	vb2_set_plane_payload(vb, 0, new_size);
 
-	return 0;
-}
-
-static enum pixel_fmt fourcc_to_ipu_pix(__u32 fourcc)
-{
-	/* Add more formats as need arises and test possibilities appear... */
-	switch (fourcc) {
-	case V4L2_PIX_FMT_RGB24:
-		return IPU_PIX_FMT_RGB24;
-	case V4L2_PIX_FMT_UYVY:
-	case V4L2_PIX_FMT_RGB565:
-	default:
-		return IPU_PIX_FMT_GENERIC;
-	}
-}
-
-static void mx3_videobuf_queue(struct vb2_buffer *vb)
-{
-	struct soc_camera_device *icd = soc_camera_from_vb2q(vb->vb2_queue);
-	struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
-	struct mx3_camera_dev *mx3_cam = ici->priv;
-	struct mx3_camera_buffer *buf = to_mx3_vb(vb);
-	struct dma_async_tx_descriptor *txd = buf->txd;
-	struct idmac_channel *ichan = to_idmac_chan(txd->chan);
-	struct idmac_video_param *video = &ichan->params.video;
-	dma_cookie_t cookie;
-	u32 fourcc = icd->current_fmt->host_fmt->fourcc;
-	unsigned long flags;
-
 	/* This is the configuration of one sg-element */
-	video->out_pixel_fmt	= fourcc_to_ipu_pix(fourcc);
+	video->out_pixel_fmt = fourcc_to_ipu_pix(host_fmt->fourcc);
 
 	if (video->out_pixel_fmt == IPU_PIX_FMT_GENERIC) {
 		/*
-		 * If the IPU DMA channel is configured to transport
-		 * generic 8-bit data, we have to set up correctly the
-		 * geometry parameters upon the current pixel format.
-		 * So, since the DMA horizontal parameters are expressed
-		 * in bytes not pixels, convert these in the right unit.
+		 * If the IPU DMA channel is configured to transfer generic
+		 * 8-bit data, we have to set up the geometry parameters
+		 * correctly, according to the current pixel format. The DMA
+		 * horizontal parameters in this case are expressed in bytes,
+		 * not in pixels.
 		 */
-		int bytes_per_line = soc_mbus_bytes_per_line(icd->user_width,
-						icd->current_fmt->host_fmt);
-		BUG_ON(bytes_per_line <= 0);
-
 		video->out_width	= bytes_per_line;
 		video->out_height	= icd->user_height;
 		video->out_stride	= bytes_per_line;
@@ -353,6 +353,7 @@ static void mx3_videobuf_queue(struct vb2_buffer *vb)
 		mx3_cam->active = NULL;
 
 	spin_unlock_irqrestore(&mx3_cam->lock, flags);
+error:
 	vb2_buffer_done(vb, VB2_BUF_STATE_ERROR);
 }
 
@@ -386,17 +387,24 @@ static void mx3_videobuf_release(struct vb2_buffer *vb)
 	}
 
 	spin_unlock_irqrestore(&mx3_cam->lock, flags);
+
+	mx3_cam->buf_total -= vb2_plane_size(vb, 0);
 }
 
 static int mx3_videobuf_init(struct vb2_buffer *vb)
 {
+	struct soc_camera_device *icd = soc_camera_from_vb2q(vb->vb2_queue);
+	struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
+	struct mx3_camera_dev *mx3_cam = ici->priv;
 	struct mx3_camera_buffer *buf = to_mx3_vb(vb);
+
 	/* This is for locking debugging only */
 	INIT_LIST_HEAD(&buf->queue);
 	sg_init_table(&buf->sg, 1);
 
 	buf->state = CSI_BUF_NEEDS_INIT;
-	buf->txd = NULL;
+
+	mx3_cam->buf_total += vb2_plane_size(vb, 0);
 
 	return 0;
 }
@@ -407,13 +415,12 @@ static int mx3_stop_streaming(struct vb2_queue *q)
 	struct soc_camera_host *ici = to_soc_camera_host(icd->parent);
 	struct mx3_camera_dev *mx3_cam = ici->priv;
 	struct idmac_channel *ichan = mx3_cam->idmac_channel[0];
-	struct dma_chan *chan;
 	struct mx3_camera_buffer *buf, *tmp;
 	unsigned long flags;
 
 	if (ichan) {
-		chan = &ichan->dma_chan;
-		chan->device->device_control(chan, DMA_TERMINATE_ALL, 0);
+		struct dma_chan *chan = &ichan->dma_chan;
+		chan->device->device_control(chan, DMA_PAUSE, 0);
 	}
 
 	spin_lock_irqsave(&mx3_cam->lock, flags);
@@ -421,8 +428,8 @@ static int mx3_stop_streaming(struct vb2_queue *q)
 	mx3_cam->active = NULL;
 
 	list_for_each_entry_safe(buf, tmp, &mx3_cam->capture, queue) {
-		buf->state = CSI_BUF_NEEDS_INIT;
 		list_del_init(&buf->queue);
+		vb2_buffer_done(&buf->vb, VB2_BUF_STATE_ERROR);
 	}
 
 	spin_unlock_irqrestore(&mx3_cam->lock, flags);
@@ -432,7 +439,6 @@ static int mx3_stop_streaming(struct vb2_queue *q)
 
 static struct vb2_ops mx3_videobuf_ops = {
 	.queue_setup	= mx3_videobuf_setup,
-	.buf_prepare	= mx3_videobuf_prepare,
 	.buf_queue	= mx3_videobuf_queue,
 	.buf_cleanup	= mx3_videobuf_release,
 	.buf_init	= mx3_videobuf_init,
@@ -516,6 +522,7 @@ static int mx3_camera_add_device(struct soc_camera_device *icd)
 
 	mx3_camera_activate(mx3_cam, icd);
 
+	mx3_cam->buf_total = 0;
 	mx3_cam->icd = icd;
 
 	dev_info(icd->parent, "MX3 Camera driver attached to camera %d\n",
@@ -1263,8 +1270,6 @@ static int __devexit mx3_camera_remove(struct platform_device *pdev)
 
 	dmaengine_put();
 
-	dev_info(&pdev->dev, "i.MX3x Camera driver unloaded\n");
-
 	return 0;
 }
 
-- 
1.7.2.5

Re: [PATCH 2/2] V4L: mx3-camera: prepare to support multi-size buffers

[Laurent Pinchart]

Hi Guennadi,

On Thursday 25 August 2011 18:46:03 Guennadi Liakhovetski wrote:
> Prepare the mx3_camera friver to support the new VIDIOC_CREATE_BUFS and
> VIDIOC_PREPARE_BUF ioctl()s. The .queue_setup() vb2 operation must be
> able to handle buffer sizes, provided by the caller, and the
> .buf_prepare() operation must not use the currently configured frame
> format for its operation, which makes it superfluous for this driver.
> Its functionality is moved into .buf_queue().

You're moving the ichan->dma_chan.device->device_prep_slave_sg() call from 
.buf_prepare() to .buf_queue(). Is that call cheap ? Otherwise it would be 
better to keep the .buf_prepare() callback.

-- 
Regards,

Laurent Pinchart

Re: [PATCH 2/2] V4L: mx3-camera: prepare to support multi-size buffers

[Guennadi Liakhovetski]

On Thu, 25 Aug 2011, Laurent Pinchart wrote:

> Hi Guennadi,
> 
> On Thursday 25 August 2011 18:46:03 Guennadi Liakhovetski wrote:
> > Prepare the mx3_camera friver to support the new VIDIOC_CREATE_BUFS and
> > VIDIOC_PREPARE_BUF ioctl()s. The .queue_setup() vb2 operation must be
> > able to handle buffer sizes, provided by the caller, and the
> > .buf_prepare() operation must not use the currently configured frame
> > format for its operation, which makes it superfluous for this driver.
> > Its functionality is moved into .buf_queue().
> 
> You're moving the ichan->dma_chan.device->device_prep_slave_sg() call from 
> .buf_prepare() to .buf_queue(). Is that call cheap ? Otherwise it would be 
> better to keep the .buf_prepare() callback.

But only if (buf->state == CSI_BUF_NEEDS_INIT), i.e., only on the first 
invocation. In any case, look at idmac_prep_slave_sg() - it is cheap. To 
do this in .buf_prepare I'd have to store the frame format from the 
.queue_setup() with a list of indices, to which it applies, and then use 
it in .buf_prepare()...

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/

Re: [PATCH 1/2] dmaengine: ipu-idmac: add support for the DMA_PAUSE control

[Vinod Koul]

On Thu, 2011-08-25 at 18:45 +0200, Guennadi Liakhovetski wrote:
> To support multi-size buffers in the mx3_camera V4L2 driver we have to be
> able to stop DMA on a channel without releasing descriptors and completely
> halting the hardware. Use the DMA_PAUSE control to implement this mode.
> 
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by Vinod Koul <vinod.koul@linux.intel.com>

Do you want this to go thru slave-dma or media tree?

-- 
~Vinod
> ---
>  drivers/dma/ipu/ipu_idmac.c |   65 +++++++++++++++++++++++++++---------------
>  1 files changed, 42 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/dma/ipu/ipu_idmac.c b/drivers/dma/ipu/ipu_idmac.c
> index c1a125e..42cdf1c 100644
> --- a/drivers/dma/ipu/ipu_idmac.c
> +++ b/drivers/dma/ipu/ipu_idmac.c
> @@ -1306,6 +1306,7 @@ static irqreturn_t idmac_interrupt(int irq, void *dev_id)
>  	    ipu_submit_buffer(ichan, descnew, sgnew, ichan->active_buffer) < 0) {
>  		callback = descnew->txd.callback;
>  		callback_param = descnew->txd.callback_param;
> +		list_del_init(&descnew->list);
>  		spin_unlock(&ichan->lock);
>  		if (callback)
>  			callback(callback_param);
> @@ -1427,39 +1428,58 @@ static int __idmac_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
>  {
>  	struct idmac_channel *ichan = to_idmac_chan(chan);
>  	struct idmac *idmac = to_idmac(chan->device);
> +	struct ipu *ipu = to_ipu(idmac);
> +	struct list_head *list, *tmp;
>  	unsigned long flags;
>  	int i;
>  
> -	/* Only supports DMA_TERMINATE_ALL */
> -	if (cmd != DMA_TERMINATE_ALL)
> -		return -ENXIO;
> +	switch (cmd) {
> +	case DMA_PAUSE:
> +		spin_lock_irqsave(&ipu->lock, flags);
> +		ipu_ic_disable_task(ipu, chan->chan_id);
>  
> -	ipu_disable_channel(idmac, ichan,
> -			    ichan->status >= IPU_CHANNEL_ENABLED);
> +		/* Return all descriptors into "prepared" state */
> +		list_for_each_safe(list, tmp, &ichan->queue)
> +			list_del_init(list);
>  
> -	tasklet_disable(&to_ipu(idmac)->tasklet);
> +		ichan->sg[0] = NULL;
> +		ichan->sg[1] = NULL;
>  
> -	/* ichan->queue is modified in ISR, have to spinlock */
> -	spin_lock_irqsave(&ichan->lock, flags);
> -	list_splice_init(&ichan->queue, &ichan->free_list);
> +		spin_unlock_irqrestore(&ipu->lock, flags);
>  
> -	if (ichan->desc)
> -		for (i = 0; i < ichan->n_tx_desc; i++) {
> -			struct idmac_tx_desc *desc = ichan->desc + i;
> -			if (list_empty(&desc->list))
> -				/* Descriptor was prepared, but not submitted */
> -				list_add(&desc->list, &ichan->free_list);
> +		ichan->status = IPU_CHANNEL_INITIALIZED;
> +		break;
> +	case DMA_TERMINATE_ALL:
> +		ipu_disable_channel(idmac, ichan,
> +				    ichan->status >= IPU_CHANNEL_ENABLED);
>  
> -			async_tx_clear_ack(&desc->txd);
> -		}
> +		tasklet_disable(&ipu->tasklet);
>  
> -	ichan->sg[0] = NULL;
> -	ichan->sg[1] = NULL;
> -	spin_unlock_irqrestore(&ichan->lock, flags);
> +		/* ichan->queue is modified in ISR, have to spinlock */
> +		spin_lock_irqsave(&ichan->lock, flags);
> +		list_splice_init(&ichan->queue, &ichan->free_list);
>  
> -	tasklet_enable(&to_ipu(idmac)->tasklet);
> +		if (ichan->desc)
> +			for (i = 0; i < ichan->n_tx_desc; i++) {
> +				struct idmac_tx_desc *desc = ichan->desc + i;
> +				if (list_empty(&desc->list))
> +					/* Descriptor was prepared, but not submitted */
> +					list_add(&desc->list, &ichan->free_list);
>  
> -	ichan->status = IPU_CHANNEL_INITIALIZED;
> +				async_tx_clear_ack(&desc->txd);
> +			}
> +
> +		ichan->sg[0] = NULL;
> +		ichan->sg[1] = NULL;
> +		spin_unlock_irqrestore(&ichan->lock, flags);
> +
> +		tasklet_enable(&ipu->tasklet);
> +
> +		ichan->status = IPU_CHANNEL_INITIALIZED;
> +		break;
> +	default:
> +		return -ENOSYS;
> +	}
>  
>  	return 0;
>  }
> @@ -1662,7 +1682,6 @@ static void __exit ipu_idmac_exit(struct ipu *ipu)
>  		struct idmac_channel *ichan = ipu->channel + i;
>  
>  		idmac_control(&ichan->dma_chan, DMA_TERMINATE_ALL, 0);
> -		idmac_prep_slave_sg(&ichan->dma_chan, NULL, 0, DMA_NONE, 0);
>  	}
>  
>  	dma_async_device_unregister(&idmac->dma);

Re: [PATCH 1/2] dmaengine: ipu-idmac: add support for the DMA_PAUSE control

[Guennadi Liakhovetski]

On Mon, 29 Aug 2011, Vinod Koul wrote:

> On Thu, 2011-08-25 at 18:45 +0200, Guennadi Liakhovetski wrote:
> > To support multi-size buffers in the mx3_camera V4L2 driver we have to be
> > able to stop DMA on a channel without releasing descriptors and completely
> > halting the hardware. Use the DMA_PAUSE control to implement this mode.
> > 
> > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> Acked-by Vinod Koul <vinod.koul@linux.intel.com>
> 
> Do you want this to go thru slave-dma or media tree?

With your above ack I can pull it together with the final form of patch 
2/2, when it's ready, via media tree. 

Thanks
Guennadi

> 
> -- 
> ~Vinod
> > ---
> >  drivers/dma/ipu/ipu_idmac.c |   65 +++++++++++++++++++++++++++---------------
> >  1 files changed, 42 insertions(+), 23 deletions(-)
> > 
> > diff --git a/drivers/dma/ipu/ipu_idmac.c b/drivers/dma/ipu/ipu_idmac.c
> > index c1a125e..42cdf1c 100644
> > --- a/drivers/dma/ipu/ipu_idmac.c
> > +++ b/drivers/dma/ipu/ipu_idmac.c
> > @@ -1306,6 +1306,7 @@ static irqreturn_t idmac_interrupt(int irq, void *dev_id)
> >  	    ipu_submit_buffer(ichan, descnew, sgnew, ichan->active_buffer) < 0) {
> >  		callback = descnew->txd.callback;
> >  		callback_param = descnew->txd.callback_param;
> > +		list_del_init(&descnew->list);
> >  		spin_unlock(&ichan->lock);
> >  		if (callback)
> >  			callback(callback_param);
> > @@ -1427,39 +1428,58 @@ static int __idmac_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
> >  {
> >  	struct idmac_channel *ichan = to_idmac_chan(chan);
> >  	struct idmac *idmac = to_idmac(chan->device);
> > +	struct ipu *ipu = to_ipu(idmac);
> > +	struct list_head *list, *tmp;
> >  	unsigned long flags;
> >  	int i;
> >  
> > -	/* Only supports DMA_TERMINATE_ALL */
> > -	if (cmd != DMA_TERMINATE_ALL)
> > -		return -ENXIO;
> > +	switch (cmd) {
> > +	case DMA_PAUSE:
> > +		spin_lock_irqsave(&ipu->lock, flags);
> > +		ipu_ic_disable_task(ipu, chan->chan_id);
> >  
> > -	ipu_disable_channel(idmac, ichan,
> > -			    ichan->status >= IPU_CHANNEL_ENABLED);
> > +		/* Return all descriptors into "prepared" state */
> > +		list_for_each_safe(list, tmp, &ichan->queue)
> > +			list_del_init(list);
> >  
> > -	tasklet_disable(&to_ipu(idmac)->tasklet);
> > +		ichan->sg[0] = NULL;
> > +		ichan->sg[1] = NULL;
> >  
> > -	/* ichan->queue is modified in ISR, have to spinlock */
> > -	spin_lock_irqsave(&ichan->lock, flags);
> > -	list_splice_init(&ichan->queue, &ichan->free_list);
> > +		spin_unlock_irqrestore(&ipu->lock, flags);
> >  
> > -	if (ichan->desc)
> > -		for (i = 0; i < ichan->n_tx_desc; i++) {
> > -			struct idmac_tx_desc *desc = ichan->desc + i;
> > -			if (list_empty(&desc->list))
> > -				/* Descriptor was prepared, but not submitted */
> > -				list_add(&desc->list, &ichan->free_list);
> > +		ichan->status = IPU_CHANNEL_INITIALIZED;
> > +		break;
> > +	case DMA_TERMINATE_ALL:
> > +		ipu_disable_channel(idmac, ichan,
> > +				    ichan->status >= IPU_CHANNEL_ENABLED);
> >  
> > -			async_tx_clear_ack(&desc->txd);
> > -		}
> > +		tasklet_disable(&ipu->tasklet);
> >  
> > -	ichan->sg[0] = NULL;
> > -	ichan->sg[1] = NULL;
> > -	spin_unlock_irqrestore(&ichan->lock, flags);
> > +		/* ichan->queue is modified in ISR, have to spinlock */
> > +		spin_lock_irqsave(&ichan->lock, flags);
> > +		list_splice_init(&ichan->queue, &ichan->free_list);
> >  
> > -	tasklet_enable(&to_ipu(idmac)->tasklet);
> > +		if (ichan->desc)
> > +			for (i = 0; i < ichan->n_tx_desc; i++) {
> > +				struct idmac_tx_desc *desc = ichan->desc + i;
> > +				if (list_empty(&desc->list))
> > +					/* Descriptor was prepared, but not submitted */
> > +					list_add(&desc->list, &ichan->free_list);
> >  
> > -	ichan->status = IPU_CHANNEL_INITIALIZED;
> > +				async_tx_clear_ack(&desc->txd);
> > +			}
> > +
> > +		ichan->sg[0] = NULL;
> > +		ichan->sg[1] = NULL;
> > +		spin_unlock_irqrestore(&ichan->lock, flags);
> > +
> > +		tasklet_enable(&ipu->tasklet);
> > +
> > +		ichan->status = IPU_CHANNEL_INITIALIZED;
> > +		break;
> > +	default:
> > +		return -ENOSYS;
> > +	}
> >  
> >  	return 0;
> >  }
> > @@ -1662,7 +1682,6 @@ static void __exit ipu_idmac_exit(struct ipu *ipu)
> >  		struct idmac_channel *ichan = ipu->channel + i;
> >  
> >  		idmac_control(&ichan->dma_chan, DMA_TERMINATE_ALL, 0);
> > -		idmac_prep_slave_sg(&ichan->dma_chan, NULL, 0, DMA_NONE, 0);
> >  	}
> >  
> >  	dma_async_device_unregister(&idmac->dma);
> 
> 
> 

---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/