[media] tw686x: Add support for DMA contiguous interlaced frame mode

Now that the driver has the infrastructure to support more
DMA modes, let's add the DMA contiguous interlaced frame mode.

In this mode, the DMA P and B buffers are programmed with
the user-provided buffers. When a P (or B) frame is ready,
a new buffer is dequeued into P (or B).

In addition to interlaced fields, the device can also be
programmed to deliver alternate fields. Only interlaced
mode is supported for now.

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>

drivers/media/pci/tw686x/Kconfig

@@ -3,6 +3,7 @@ config VIDEO_TW686X
 	depends on PCI && VIDEO_DEV && VIDEO_V4L2 && SND
 	depends on HAS_DMA
 	select VIDEOBUF2_VMALLOC
+	select VIDEOBUF2_DMA_CONTIG
 	select SND_PCM
 	help
 	  Support for Intersil/Techwell TW686x-based frame grabber cards.

drivers/media/pci/tw686x/tw686x-core.c

@@ -63,6 +63,8 @@ static const char *dma_mode_name(unsigned int mode)
 	switch (mode) {
 	case TW686X_DMA_MODE_MEMCPY:
 		return "memcpy";
+	case TW686X_DMA_MODE_CONTIG:
+		return "contig";
 	default:
 		return "unknown";
 	}
@@ -77,6 +79,8 @@ static int tw686x_dma_mode_set(const char *val, struct kernel_param *kp)
 {
 	if (!strcasecmp(val, dma_mode_name(TW686X_DMA_MODE_MEMCPY)))
 		dma_mode = TW686X_DMA_MODE_MEMCPY;
+	else if (!strcasecmp(val, dma_mode_name(TW686X_DMA_MODE_CONTIG)))
+		dma_mode = TW686X_DMA_MODE_CONTIG;
 	else
 		return -EINVAL;
 	return 0;

drivers/media/pci/tw686x/tw686x-video.c

@@ -19,6 +19,7 @@
 #include <linux/slab.h>
 #include <media/v4l2-common.h>
 #include <media/v4l2-event.h>
+#include <media/videobuf2-dma-contig.h>
 #include <media/videobuf2-vmalloc.h>
 #include "tw686x.h"
 #include "tw686x-regs.h"
@@ -148,6 +149,53 @@ const struct tw686x_dma_ops memcpy_dma_ops = {
 	.field		= V4L2_FIELD_INTERLACED,
 };
 
+static void tw686x_contig_buf_refill(struct tw686x_video_channel *vc,
+				     unsigned int pb)
+{
+	struct tw686x_v4l2_buf *buf;
+
+	while (!list_empty(&vc->vidq_queued)) {
+		u32 reg = pb ? VDMA_B_ADDR[vc->ch] : VDMA_P_ADDR[vc->ch];
+		dma_addr_t phys;
+
+		buf = list_first_entry(&vc->vidq_queued,
+			struct tw686x_v4l2_buf, list);
+		list_del(&buf->list);
+
+		phys = vb2_dma_contig_plane_dma_addr(&buf->vb.vb2_buf, 0);
+		reg_write(vc->dev, reg, phys);
+
+		buf->vb.vb2_buf.state = VB2_BUF_STATE_ACTIVE;
+		vc->curr_bufs[pb] = buf;
+		return;
+	}
+	vc->curr_bufs[pb] = NULL;
+}
+
+static void tw686x_contig_cleanup(struct tw686x_dev *dev)
+{
+	vb2_dma_contig_cleanup_ctx(dev->alloc_ctx);
+}
+
+static int tw686x_contig_setup(struct tw686x_dev *dev)
+{
+	dev->alloc_ctx = vb2_dma_contig_init_ctx(&dev->pci_dev->dev);
+	if (IS_ERR(dev->alloc_ctx)) {
+		dev_err(&dev->pci_dev->dev, "unable to init DMA context\n");
+		return PTR_ERR(dev->alloc_ctx);
+	}
+	return 0;
+}
+
+const struct tw686x_dma_ops contig_dma_ops = {
+	.setup		= tw686x_contig_setup,
+	.cleanup	= tw686x_contig_cleanup,
+	.buf_refill	= tw686x_contig_buf_refill,
+	.mem_ops	= &vb2_dma_contig_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] = {
@@ -841,6 +889,8 @@ int tw686x_video_init(struct tw686x_dev *dev)
 
 	if (dev->dma_mode == TW686X_DMA_MODE_MEMCPY)
 		dev->dma_ops = &memcpy_dma_ops;
+	else if (dev->dma_mode == TW686X_DMA_MODE_CONTIG)
+		dev->dma_ops = &contig_dma_ops;
 	else
 		return -EINVAL;
 

drivers/media/pci/tw686x/tw686x.h

@@ -33,6 +33,7 @@
 #define TW686X_AUDIO_PERIODS_MAX	TW686X_AUDIO_PAGE_MAX
 
 #define TW686X_DMA_MODE_MEMCPY		0
+#define TW686X_DMA_MODE_CONTIG		1
 
 struct tw686x_format {
 	char *name;