[media] cx18: mmap() support for raw YUV video capture

Add support for mmap method streaming of raw YUV video on cx18-based
hardware, in addition to the existing support for read() streaming of
raw YUV and MPEG-2 encoded video.

[simon.farnsworth@onelan.co.uk: I forward-ported this from Steven's original work,
 done under contract to ONELAN. The original code is at
 http://www.kernellabs.com/hg/~stoth/cx18-videobuf]

Signed-off-by: Steven Toth <stoth@kernellabs.com>
Signed-off-by: Simon Farnsworth <simon.farnsworth@onelan.co.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/cx18/Kconfig

@@ -2,6 +2,8 @@ config VIDEO_CX18
 	tristate "Conexant cx23418 MPEG encoder support"
 	depends on VIDEO_V4L2 && DVB_CORE && PCI && I2C && EXPERIMENTAL
 	select I2C_ALGOBIT
+	select VIDEOBUF_DVB
+	select VIDEOBUF_VMALLOC
 	depends on RC_CORE
 	select VIDEO_TUNER
 	select VIDEO_TVEEPROM

drivers/media/video/cx18/cx18-driver.h

@@ -65,6 +65,10 @@
 #include "dvb_net.h"
 #include "dvbdev.h"
 
+/* Videobuf / YUV support */
+#include <media/videobuf-core.h>
+#include <media/videobuf-vmalloc.h>
+
 #ifndef CONFIG_PCI
 #  error "This driver requires kernel PCI support."
 #endif
@@ -403,13 +407,34 @@ struct cx18_stream {
 	struct cx18_queue q_idle;	/* idle - not in rotation */
 
 	struct work_struct out_work_order;
+
+	/* Videobuf for YUV video */
+	u32 pixelformat;
+	struct list_head vb_capture;    /* video capture queue */
+	spinlock_t vb_lock;
+	struct v4l2_framebuffer fbuf;
+	v4l2_std_id tvnorm; /* selected tv norm */
+	struct timer_list vb_timeout;
+	int vbwidth;
+	int vbheight;
+};
+
+struct cx18_videobuf_buffer {
+	/* Common video buffer sub-system struct */
+	struct videobuf_buffer vb;
+	v4l2_std_id tvnorm; /* selected tv norm */
+	u32 bytes_used;
 };
 
 struct cx18_open_id {
 	struct v4l2_fh fh;
 	u32 open_id;
 	int type;
 	struct cx18 *cx;
+
+	struct videobuf_queue vbuf_q;
+	spinlock_t s_lock; /* Protect vbuf_q */
+	enum v4l2_buf_type vb_type;
 };
 
 static inline struct cx18_open_id *fh2id(struct v4l2_fh *fh)

drivers/media/video/cx18/cx18-fileops.c

@@ -597,6 +597,13 @@ ssize_t cx18_v4l2_read(struct file *filp, char __user *buf, size_t count,
 	mutex_unlock(&cx->serialize_lock);
 	if (rc)
 		return rc;
+
+	if ((id->vb_type == V4L2_BUF_TYPE_VIDEO_CAPTURE) &&
+		(id->type == CX18_ENC_STREAM_TYPE_YUV)) {
+		return videobuf_read_stream(&id->vbuf_q, buf, count, pos, 0,
+			filp->f_flags & O_NONBLOCK);
+	}
+
 	return cx18_read_pos(s, buf, count, pos, filp->f_flags & O_NONBLOCK);
 }
 
@@ -622,6 +629,11 @@ unsigned int cx18_v4l2_enc_poll(struct file *filp, poll_table *wait)
 		CX18_DEBUG_FILE("Encoder poll started capture\n");
 	}
 
+	if ((id->vb_type == V4L2_BUF_TYPE_VIDEO_CAPTURE) &&
+		(id->type == CX18_ENC_STREAM_TYPE_YUV)) {
+		return videobuf_poll_stream(filp, &id->vbuf_q, wait);
+	}
+
 	/* add stream's waitq to the poll list */
 	CX18_DEBUG_HI_FILE("Encoder poll\n");
 	poll_wait(filp, &s->waitq, wait);
@@ -633,6 +645,58 @@ unsigned int cx18_v4l2_enc_poll(struct file *filp, poll_table *wait)
 	return 0;
 }
 
+int cx18_v4l2_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct cx18_open_id *id = file->private_data;
+	struct cx18 *cx = id->cx;
+	struct cx18_stream *s = &cx->streams[id->type];
+	int eof = test_bit(CX18_F_S_STREAMOFF, &s->s_flags);
+
+	if ((id->vb_type == V4L2_BUF_TYPE_VIDEO_CAPTURE) &&
+		(id->type == CX18_ENC_STREAM_TYPE_YUV)) {
+
+		/* Start a capture if there is none */
+		if (!eof && !test_bit(CX18_F_S_STREAMING, &s->s_flags)) {
+			int rc;
+
+			mutex_lock(&cx->serialize_lock);
+			rc = cx18_start_capture(id);
+			mutex_unlock(&cx->serialize_lock);
+			if (rc) {
+				CX18_DEBUG_INFO(
+					"Could not start capture for %s (%d)\n",
+					s->name, rc);
+				return -EINVAL;
+			}
+			CX18_DEBUG_FILE("Encoder poll started capture\n");
+		}
+
+		return videobuf_mmap_mapper(&id->vbuf_q, vma);
+	}
+
+	return -EINVAL;
+}
+
+void cx18_vb_timeout(unsigned long data)
+{
+	struct cx18_stream *s = (struct cx18_stream *)data;
+	struct cx18_videobuf_buffer *buf;
+	unsigned long flags;
+
+	/* Return all of the buffers in error state, so the vbi/vid inode
+	 * can return from blocking.
+	 */
+	spin_lock_irqsave(&s->vb_lock, flags);
+	while (!list_empty(&s->vb_capture)) {
+		buf = list_entry(s->vb_capture.next,
+			struct cx18_videobuf_buffer, vb.queue);
+		list_del(&buf->vb.queue);
+		buf->vb.state = VIDEOBUF_ERROR;
+		wake_up(&buf->vb.done);
+	}
+	spin_unlock_irqrestore(&s->vb_lock, flags);
+}
+
 void cx18_stop_capture(struct cx18_open_id *id, int gop_end)
 {
 	struct cx18 *cx = id->cx;
@@ -716,12 +780,150 @@ int cx18_v4l2_close(struct file *filp)
 		cx18_release_stream(s);
 	} else {
 		cx18_stop_capture(id, 0);
+		if (id->type == CX18_ENC_STREAM_TYPE_YUV)
+			videobuf_mmap_free(&id->vbuf_q);
 	}
 	kfree(id);
 	mutex_unlock(&cx->serialize_lock);
 	return 0;
 }
 
+void cx18_dma_free(struct videobuf_queue *q,
+	struct cx18_stream *s, struct cx18_videobuf_buffer *buf)
+{
+	videobuf_waiton(q, &buf->vb, 0, 0);
+	videobuf_vmalloc_free(&buf->vb);
+	buf->vb.state = VIDEOBUF_NEEDS_INIT;
+}
+
+static int cx18_prepare_buffer(struct videobuf_queue *q,
+	struct cx18_stream *s,
+	struct cx18_videobuf_buffer *buf,
+	u32 pixelformat,
+	unsigned int width, unsigned int height,
+	enum v4l2_field field)
+{
+	int rc = 0;
+
+	/* check settings */
+	buf->bytes_used = 0;
+
+	if ((width  < 48) || (height < 32))
+		return -EINVAL;
+
+	buf->vb.size = (width * height * 16 /*fmt->depth*/) >> 3;
+	if ((buf->vb.baddr != 0) && (buf->vb.bsize < buf->vb.size))
+		return -EINVAL;
+
+	/* alloc + fill struct (if changed) */
+	if (buf->vb.width != width || buf->vb.height != height ||
+	    buf->vb.field != field || s->pixelformat != pixelformat ||
+	    buf->tvnorm != s->tvnorm) {
+
+		buf->vb.width  = width;
+		buf->vb.height = height;
+		buf->vb.field  = field;
+		buf->tvnorm    = s->tvnorm;
+		s->pixelformat = pixelformat;
+
+		cx18_dma_free(q, s, buf);
+	}
+
+	if ((buf->vb.baddr != 0) && (buf->vb.bsize < buf->vb.size))
+		return -EINVAL;
+
+	if (buf->vb.field == 0)
+		buf->vb.field = V4L2_FIELD_INTERLACED;
+
+	if (VIDEOBUF_NEEDS_INIT == buf->vb.state) {
+		buf->vb.width  = width;
+		buf->vb.height = height;
+		buf->vb.field  = field;
+		buf->tvnorm    = s->tvnorm;
+		s->pixelformat = pixelformat;
+
+		rc = videobuf_iolock(q, &buf->vb, &s->fbuf);
+		if (rc != 0)
+			goto fail;
+	}
+	buf->vb.state = VIDEOBUF_PREPARED;
+	return 0;
+
+fail:
+	cx18_dma_free(q, s, buf);
+	return rc;
+
+}
+
+#define VB_MIN_BUFFERS 32
+#define VB_MIN_BUFSIZE 0x208000
+
+static int buffer_setup(struct videobuf_queue *q,
+	unsigned int *count, unsigned int *size)
+{
+	struct cx18_open_id *id = q->priv_data;
+	struct cx18 *cx = id->cx;
+	struct cx18_stream *s = &cx->streams[id->type];
+
+	*size = 2 * s->vbwidth * s->vbheight;
+	if (*count == 0)
+		*count = VB_MIN_BUFFERS;
+
+	while (*size * *count > VB_MIN_BUFFERS * VB_MIN_BUFSIZE)
+		(*count)--;
+
+	q->field = V4L2_FIELD_INTERLACED;
+	q->last = V4L2_FIELD_INTERLACED;
+
+	return 0;
+}
+
+static int buffer_prepare(struct videobuf_queue *q,
+	struct videobuf_buffer *vb,
+	enum v4l2_field field)
+{
+	struct cx18_videobuf_buffer *buf =
+		container_of(vb, struct cx18_videobuf_buffer, vb);
+	struct cx18_open_id *id = q->priv_data;
+	struct cx18 *cx = id->cx;
+	struct cx18_stream *s = &cx->streams[id->type];
+
+	return cx18_prepare_buffer(q, s, buf, s->pixelformat,
+		s->vbwidth, s->vbheight, field);
+}
+
+static void buffer_release(struct videobuf_queue *q,
+	struct videobuf_buffer *vb)
+{
+	struct cx18_videobuf_buffer *buf =
+		container_of(vb, struct cx18_videobuf_buffer, vb);
+	struct cx18_open_id *id = q->priv_data;
+	struct cx18 *cx = id->cx;
+	struct cx18_stream *s = &cx->streams[id->type];
+
+	cx18_dma_free(q, s, buf);
+}
+
+static void buffer_queue(struct videobuf_queue *q, struct videobuf_buffer *vb)
+{
+	struct cx18_videobuf_buffer *buf =
+		container_of(vb, struct cx18_videobuf_buffer, vb);
+	struct cx18_open_id *id = q->priv_data;
+	struct cx18 *cx = id->cx;
+	struct cx18_stream *s = &cx->streams[id->type];
+
+	buf->vb.state = VIDEOBUF_QUEUED;
+
+	list_add_tail(&buf->vb.queue, &s->vb_capture);
+}
+
+static struct videobuf_queue_ops cx18_videobuf_qops = {
+	.buf_setup    = buffer_setup,
+	.buf_prepare  = buffer_prepare,
+	.buf_queue    = buffer_queue,
+	.buf_release  = buffer_release,
+};
+
 static int cx18_serialized_open(struct cx18_stream *s, struct file *filp)
 {
 	struct cx18 *cx = s->cx;
@@ -740,6 +942,9 @@ static int cx18_serialized_open(struct cx18_stream *s, struct file *filp)
 	item->cx = cx;
 	item->type = s->type;
 
+	spin_lock_init(&item->s_lock);
+	item->vb_type = 0;
+
 	item->open_id = cx->open_id++;
 	filp->private_data = &item->fh;
 
@@ -774,6 +979,15 @@ static int cx18_serialized_open(struct cx18_stream *s, struct file *filp)
 		/* Done! Unmute and continue. */
 		cx18_unmute(cx);
 	}
+	if (item->type == CX18_ENC_STREAM_TYPE_YUV) {
+		item->vb_type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+		videobuf_queue_vmalloc_init(&item->vbuf_q, &cx18_videobuf_qops,
+			&cx->pci_dev->dev, &item->s_lock,
+			V4L2_BUF_TYPE_VIDEO_CAPTURE,
+			V4L2_FIELD_INTERLACED,
+			sizeof(struct cx18_videobuf_buffer),
+			item, &cx->serialize_lock);
+	}
 	v4l2_fh_add(&item->fh);
 	return 0;
 }

drivers/media/video/cx18/cx18-fileops.h

@@ -33,6 +33,8 @@ int cx18_start_capture(struct cx18_open_id *id);
 void cx18_stop_capture(struct cx18_open_id *id, int gop_end);
 void cx18_mute(struct cx18 *cx);
 void cx18_unmute(struct cx18 *cx);
+int cx18_v4l2_mmap(struct file *file, struct vm_area_struct *vma);
+void cx18_vb_timeout(unsigned long data);
 
 /* Shared with cx18-alsa module */
 int cx18_claim_stream(struct cx18_open_id *id, int type);