[media] tw686x: Introduce an interface to support multiple DMA modes

Let's set the corner stone to support all the DMA modes
available on this device.

For stability reasons, the driver is currently setting DMA frame
mode, and using single DMA buffers to get the P and B buffers.
Each frame is then memcpy'ed into the user buffer.

However, other platforms might be interested in avoiding this
memcpy, or in taking advantage of the chip's DMA scatter-gather
capabilities.

To achieve this, this commit introduces a "dma_mode" module parameter,
and a tw686x_dma_ops struct. This will allow to define functions to
alloc/free DMA buffers, and to return the frames to userspace.

The memcpy-based method described above is named as dma_mode="memcpy".
Current alloc/free functions are renamed as tw686x_memcpy_xxx,
and are now used through a memcpy_dma_ops.

Tested-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 146 insertions, 108 deletions

diff --git a/drivers/media/pci/tw686x/tw686x-video.c b/drivers/media/pci/tw686x/tw686x-video.c
index 253e10823ba3..c0d2a9bd5414 100644
--- a/drivers/media/pci/tw686x/tw686x-video.c
+++ b/drivers/media/pci/tw686x/tw686x-video.c
@@ -43,6 +43,111 @@ static const struct tw686x_format formats[] = {
 	}
 };
 
+static void tw686x_buf_done(struct tw686x_video_channel *vc,
+			    unsigned int pb)
+{
+	struct tw686x_dma_desc *desc = &vc->dma_descs[pb];
+	struct tw686x_dev *dev = vc->dev;
+	struct vb2_v4l2_buffer *vb;
+	struct vb2_buffer *vb2_buf;
+
+	if (vc->curr_bufs[pb]) {
+		vb = &vc->curr_bufs[pb]->vb;
+
+		vb->field = dev->dma_ops->field;
+		vb->sequence = vc->sequence++;
+		vb2_buf = &vb->vb2_buf;
+
+		if (dev->dma_mode == TW686X_DMA_MODE_MEMCPY)
+			memcpy(vb2_plane_vaddr(vb2_buf, 0), desc->virt,
+			       desc->size);
+		vb2_buf->timestamp = ktime_get_ns();
+		vb2_buffer_done(vb2_buf, VB2_BUF_STATE_DONE);
+	}
+
+	vc->pb = !pb;
+}
+
+/*
+ * We can call this even when alloc_dma failed for the given channel
+ */
+static void tw686x_memcpy_dma_free(struct tw686x_video_channel *vc,
+				   unsigned int pb)
+{
+	struct tw686x_dma_desc *desc = &vc->dma_descs[pb];
+	struct tw686x_dev *dev = vc->dev;
+	struct pci_dev *pci_dev;
+	unsigned long flags;
+
+	/* Check device presence. Shouldn't really happen! */
+	spin_lock_irqsave(&dev->lock, flags);
+	pci_dev = dev->pci_dev;
+	spin_unlock_irqrestore(&dev->lock, flags);
+	if (!pci_dev) {
+		WARN(1, "trying to deallocate on missing device\n");
+		return;
+	}
+
+	if (desc->virt) {
+		pci_free_consistent(dev->pci_dev, desc->size,
+				    desc->virt, desc->phys);
+		desc->virt = NULL;
+	}
+}
+
+static int tw686x_memcpy_dma_alloc(struct tw686x_video_channel *vc,
+				   unsigned int pb)
+{
+	struct tw686x_dev *dev = vc->dev;
+	u32 reg = pb ? VDMA_B_ADDR[vc->ch] : VDMA_P_ADDR[vc->ch];
+	unsigned int len;
+	void *virt;
+
+	WARN(vc->dma_descs[pb].virt,
+	     "Allocating buffer but previous still here\n");
+
+	len = (vc->width * vc->height * vc->format->depth) >> 3;
+	virt = pci_alloc_consistent(dev->pci_dev, len,
+				    &vc->dma_descs[pb].phys);
+	if (!virt) {
+		v4l2_err(&dev->v4l2_dev,
+			 "dma%d: unable to allocate %s-buffer\n",
+			 vc->ch, pb ? "B" : "P");
+		return -ENOMEM;
+	}
+	vc->dma_descs[pb].size = len;
+	vc->dma_descs[pb].virt = virt;
+	reg_write(dev, reg, vc->dma_descs[pb].phys);
+
+	return 0;
+}
+
+static void tw686x_memcpy_buf_refill(struct tw686x_video_channel *vc,
+				     unsigned int pb)
+{
+	struct tw686x_v4l2_buf *buf;
+
+	while (!list_empty(&vc->vidq_queued)) {
+
+		buf = list_first_entry(&vc->vidq_queued,
+			struct tw686x_v4l2_buf, list);
+		list_del(&buf->list);
+
+		vc->curr_bufs[pb] = buf;
+		return;
+	}
+	vc->curr_bufs[pb] = NULL;
+}
+
+const struct tw686x_dma_ops memcpy_dma_ops = {
+	.alloc		= tw686x_memcpy_dma_alloc,
+	.free		= tw686x_memcpy_dma_free,
+	.buf_refill	= tw686x_memcpy_buf_refill,
+	.mem_ops	= &vb2_vmalloc_memops,
+	.hw_dma_mode	= TW686X_FRAME_MODE,
+	.field		= V4L2_FIELD_INTERLACED,
+};
+
 static unsigned int tw686x_fields_map(v4l2_std_id std, unsigned int fps)
 {
 	static const unsigned int map[15] = {
@@ -123,6 +228,7 @@ static int tw686x_queue_setup(struct vb2_queue *vq,
 		return 0;
 	}
 
+	alloc_ctxs[0] = vc->dev->alloc_ctx;
 	sizes[0] = szimage;
 	*nplanes = 1;
 	return 0;
@@ -152,75 +258,6 @@ static void tw686x_buf_queue(struct vb2_buffer *vb)
 	spin_unlock_irqrestore(&vc->qlock, flags);
 }
 
-/*
- * We can call this even when alloc_dma failed for the given channel
- */
-static void tw686x_free_dma(struct tw686x_video_channel *vc, unsigned int pb)
-{
-	struct tw686x_dma_desc *desc = &vc->dma_descs[pb];
-	struct tw686x_dev *dev = vc->dev;
-	struct pci_dev *pci_dev;
-	unsigned long flags;
-
-	/* Check device presence. Shouldn't really happen! */
-	spin_lock_irqsave(&dev->lock, flags);
-	pci_dev = dev->pci_dev;
-	spin_unlock_irqrestore(&dev->lock, flags);
-	if (!pci_dev) {
-		WARN(1, "trying to deallocate on missing device\n");
-		return;
-	}
-
-	if (desc->virt) {
-		pci_free_consistent(dev->pci_dev, desc->size,
-				    desc->virt, desc->phys);
-		desc->virt = NULL;
-	}
-}
-
-static int tw686x_alloc_dma(struct tw686x_video_channel *vc, unsigned int pb)
-{
-	struct tw686x_dev *dev = vc->dev;
-	u32 reg = pb ? VDMA_B_ADDR[vc->ch] : VDMA_P_ADDR[vc->ch];
-	unsigned int len;
-	void *virt;
-
-	WARN(vc->dma_descs[pb].virt,
-	     "Allocating buffer but previous still here\n");
-
-	len = (vc->width * vc->height * vc->format->depth) >> 3;
-	virt = pci_alloc_consistent(dev->pci_dev, len,
-				    &vc->dma_descs[pb].phys);
-	if (!virt) {
-		v4l2_err(&dev->v4l2_dev,
-			 "dma%d: unable to allocate %s-buffer\n",
-			 vc->ch, pb ? "B" : "P");
-		return -ENOMEM;
-	}
-	vc->dma_descs[pb].size = len;
-	vc->dma_descs[pb].virt = virt;
-	reg_write(dev, reg, vc->dma_descs[pb].phys);
-
-	return 0;
-}
-
-static void tw686x_buffer_refill(struct tw686x_video_channel *vc,
-				 unsigned int pb)
-{
-	struct tw686x_v4l2_buf *buf;
-
-	while (!list_empty(&vc->vidq_queued)) {
-
-		buf = list_first_entry(&vc->vidq_queued,
-			struct tw686x_v4l2_buf, list);
-		list_del(&buf->list);
-
-		vc->curr_bufs[pb] = buf;
-		return;
-	}
-	vc->curr_bufs[pb] = NULL;
-}
-
 static void tw686x_clear_queue(struct tw686x_video_channel *vc,
 			       enum vb2_buffer_state state)
 {
@@ -262,7 +299,8 @@ static int tw686x_start_streaming(struct vb2_queue *vq, unsigned int count)
 	spin_lock_irqsave(&vc->qlock, flags);
 
 	/* Sanity check */
-	if (!vc->dma_descs[0].virt || !vc->dma_descs[1].virt) {
+	if (dev->dma_mode == TW686X_DMA_MODE_MEMCPY &&
+	    (!vc->dma_descs[0].virt || !vc->dma_descs[1].virt)) {
 		spin_unlock_irqrestore(&vc->qlock, flags);
 		v4l2_err(&dev->v4l2_dev,
 			 "video%d: refusing to start without DMA buffers\n",
@@ -272,7 +310,7 @@ static int tw686x_start_streaming(struct vb2_queue *vq, unsigned int count)
 	}
 
 	for (pb = 0; pb < 2; pb++)
-		tw686x_buffer_refill(vc, pb);
+		dev->dma_ops->buf_refill(vc, pb);
 	spin_unlock_irqrestore(&vc->qlock, flags);
 
 	vc->sequence = 0;
@@ -375,10 +413,11 @@ static int tw686x_g_fmt_vid_cap(struct file *file, void *priv,
 				struct v4l2_format *f)
 {
 	struct tw686x_video_channel *vc = video_drvdata(file);
+	struct tw686x_dev *dev = vc->dev;
 
 	f->fmt.pix.width = vc->width;
 	f->fmt.pix.height = vc->height;
-	f->fmt.pix.field = V4L2_FIELD_INTERLACED;
+	f->fmt.pix.field = dev->dma_ops->field;
 	f->fmt.pix.pixelformat = vc->format->fourcc;
 	f->fmt.pix.colorspace = V4L2_COLORSPACE_SMPTE170M;
 	f->fmt.pix.bytesperline = (f->fmt.pix.width * vc->format->depth) / 8;
@@ -390,6 +429,7 @@ static int tw686x_try_fmt_vid_cap(struct file *file, void *priv,
 				  struct v4l2_format *f)
 {
 	struct tw686x_video_channel *vc = video_drvdata(file);
+	struct tw686x_dev *dev = vc->dev;
 	unsigned int video_height = TW686X_VIDEO_HEIGHT(vc->video_standard);
 	const struct tw686x_format *format;
 
@@ -412,7 +452,7 @@ static int tw686x_try_fmt_vid_cap(struct file *file, void *priv,
 	f->fmt.pix.bytesperline = (f->fmt.pix.width * format->depth) / 8;
 	f->fmt.pix.sizeimage = f->fmt.pix.height * f->fmt.pix.bytesperline;
 	f->fmt.pix.colorspace = V4L2_COLORSPACE_SMPTE170M;
-	f->fmt.pix.field = V4L2_FIELD_INTERLACED;
+	f->fmt.pix.field = dev->dma_ops->field;
 
 	return 0;
 }
@@ -421,6 +461,7 @@ static int tw686x_s_fmt_vid_cap(struct file *file, void *priv,
 				struct v4l2_format *f)
 {
 	struct tw686x_video_channel *vc = video_drvdata(file);
+	struct tw686x_dev *dev = vc->dev;
 	u32 val, width, line_width, height;
 	unsigned long bitsperframe;
 	int err, pb;
@@ -438,15 +479,16 @@ static int tw686x_s_fmt_vid_cap(struct file *file, void *priv,
 	vc->height = f->fmt.pix.height;
 
 	/* We need new DMA buffers if the framesize has changed */
-	if (bitsperframe != vc->width * vc->height * vc->format->depth) {
+	if (dev->dma_ops->alloc &&
+	    bitsperframe != vc->width * vc->height * vc->format->depth) {
 		for (pb = 0; pb < 2; pb++)
-			tw686x_free_dma(vc, pb);
+			dev->dma_ops->free(vc, pb);
 
 		for (pb = 0; pb < 2; pb++) {
-			err = tw686x_alloc_dma(vc, pb);
+			err = dev->dma_ops->alloc(vc, pb);
 			if (err) {
 				if (pb > 0)
-					tw686x_free_dma(vc, 0);
+					dev->dma_ops->free(vc, 0);
 				return err;
 			}
 		}
@@ -713,26 +755,11 @@ static const struct v4l2_ioctl_ops tw686x_video_ioctl_ops = {
 	.vidioc_unsubscribe_event	= v4l2_event_unsubscribe,
 };
 
-static void tw686x_buffer_copy(struct tw686x_video_channel *vc,
-			       unsigned int pb, struct vb2_v4l2_buffer *vb)
-{
-	struct tw686x_dma_desc *desc = &vc->dma_descs[pb];
-	struct vb2_buffer *vb2_buf = &vb->vb2_buf;
-
-	vb->field = V4L2_FIELD_INTERLACED;
-	vb->sequence = vc->sequence++;
-
-	memcpy(vb2_plane_vaddr(vb2_buf, 0), desc->virt, desc->size);
-	vb2_buf->timestamp = ktime_get_ns();
-	vb2_buffer_done(vb2_buf, VB2_BUF_STATE_DONE);
-}
-
 void tw686x_video_irq(struct tw686x_dev *dev, unsigned long requests,
 		      unsigned int pb_status, unsigned int fifo_status,
 		      unsigned int *reset_ch)
 {
 	struct tw686x_video_channel *vc;
-	struct vb2_v4l2_buffer *vb;
 	unsigned long flags;
 	unsigned int ch, pb;
 
@@ -781,14 +808,9 @@ void tw686x_video_irq(struct tw686x_dev *dev, unsigned long requests,
 			continue;
 		}
 
-		/* handle video stream */
 		spin_lock_irqsave(&vc->qlock, flags);
-		if (vc->curr_bufs[pb]) {
-			vb = &vc->curr_bufs[pb]->vb;
-			tw686x_buffer_copy(vc, pb, vb);
-		}
-		vc->pb = !pb;
-		tw686x_buffer_refill(vc, pb);
+		tw686x_buf_done(vc, pb);
+		dev->dma_ops->buf_refill(vc, pb);
 		spin_unlock_irqrestore(&vc->qlock, flags);
 	}
 }
@@ -803,9 +825,13 @@ void tw686x_video_free(struct tw686x_dev *dev)
 		if (vc->device)
 			video_unregister_device(vc->device);
 
-		for (pb = 0; pb < 2; pb++)
-			tw686x_free_dma(vc, pb);
+		if (dev->dma_ops->free)
+			for (pb = 0; pb < 2; pb++)
+				dev->dma_ops->free(vc, pb);
 	}
+
+	if (dev->dma_ops->cleanup)
+		dev->dma_ops->cleanup(dev);
 }
 
 int tw686x_video_init(struct tw686x_dev *dev)
@@ -813,10 +839,21 @@ int tw686x_video_init(struct tw686x_dev *dev)
 	unsigned int ch, val, pb;
 	int err;
 
+	if (dev->dma_mode == TW686X_DMA_MODE_MEMCPY)
+		dev->dma_ops = &memcpy_dma_ops;
+	else
+		return -EINVAL;
+
 	err = v4l2_device_register(&dev->pci_dev->dev, &dev->v4l2_dev);
 	if (err)
 		return err;
 
+	if (dev->dma_ops->setup) {
+		err = dev->dma_ops->setup(dev);
+		if (err)
+			return err;
+	}
+
 	for (ch = 0; ch < max_channels(dev); ch++) {
 		struct tw686x_video_channel *vc = &dev->video_channels[ch];
 		struct video_device *vdev;
@@ -842,10 +879,12 @@ int tw686x_video_init(struct tw686x_dev *dev)
 		reg_write(dev, HACTIVE_LO[ch], 0xd0);
 		reg_write(dev, VIDEO_SIZE[ch], 0);
 
-		for (pb = 0; pb < 2; pb++) {
-			err = tw686x_alloc_dma(vc, pb);
-			if (err)
-				goto error;
+		if (dev->dma_ops->alloc) {
+			for (pb = 0; pb < 2; pb++) {
+				err = dev->dma_ops->alloc(vc, pb);
+				if (err)
+					goto error;
+			}
 		}
 
 		vc->vidq.io_modes = VB2_READ | VB2_MMAP | VB2_DMABUF;
@@ -853,7 +892,7 @@ int tw686x_video_init(struct tw686x_dev *dev)
 		vc->vidq.drv_priv = vc;
 		vc->vidq.buf_struct_size = sizeof(struct tw686x_v4l2_buf);
 		vc->vidq.ops = &tw686x_video_qops;
-		vc->vidq.mem_ops = &vb2_vmalloc_memops;
+		vc->vidq.mem_ops = dev->dma_ops->mem_ops;
 		vc->vidq.timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
 		vc->vidq.min_buffers_needed = 2;
 		vc->vidq.lock = &vc->vb_mutex;
@@ -915,10 +954,9 @@ int tw686x_video_init(struct tw686x_dev *dev)
 		vc->num = vdev->num;
 	}
 
-	/* Set DMA frame mode on all channels. Only supported mode for now. */
 	val = TW686X_DEF_PHASE_REF;
 	for (ch = 0; ch < max_channels(dev); ch++)
-		val |= TW686X_FRAME_MODE << (16 + ch * 2);
+		val |= dev->dma_ops->hw_dma_mode << (16 + ch * 2);
 	reg_write(dev, PHASE_REF, val);
 
 	reg_write(dev, MISC2[0], 0xe7);