3 files changed, 272 insertions, 0 deletions

diff --git a/v4l2-hdmi-example/CHANGELOG b/v4l2-hdmi-example/CHANGELOG
new file mode 100644
index 0000000..673729c
--- /dev/null
+++ b/v4l2-hdmi-example/CHANGELOG
@@ -0,0 +1 @@
+Version 0.1
diff --git a/v4l2-hdmi-example/README b/v4l2-hdmi-example/README
new file mode 100644
index 0000000..52e67ad
--- /dev/null
+++ b/v4l2-hdmi-example/README
@@ -0,0 +1,12 @@
+
+Compilation:
+
+arm-linux-gnueabi-gcc main.c -o tvdemo -Ikernel/usr/include/ -std=gnu99 -lm -O2
+
+Command line example
+
+./tvdemo /dev/video10 720 480 0 0
+
+TODO:
+
+Add Makefile
diff --git a/v4l2-hdmi-example/main.c b/v4l2-hdmi-example/main.c
new file mode 100644
index 0000000..32308a1
--- /dev/null
+++ b/v4l2-hdmi-example/main.c
@@ -0,0 +1,259 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/videodev2.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#define ERRSTR strerror(errno)
+
+#define BYE_ON(cond, ...) \
+do { \
+	if (cond) { \
+		int errsv = errno; \
+		fprintf(stderr, "ERROR(%s:%d) : ", \
+			__FILE__, __LINE__); \
+		errno = errsv; \
+		fprintf(stderr,  __VA_ARGS__); \
+		abort(); \
+	} \
+} while(0)
+
+#define BUFFER_CNT	3
+
+struct buffer {
+	int index;
+	void *data;
+	size_t size;
+	size_t width;
+	size_t height;
+
+	/* buffer state */
+	double t;
+};
+
+struct setup {
+	char *path;
+	int width;
+	int height;
+	int xoffset;
+	int yoffset;
+};
+
+struct context {
+	int fd;
+	struct buffer *buffer;
+	size_t buffer_cnt;
+};
+
+int parse_args(struct setup *setup, int argc, char *argv[]);
+
+int showtime(struct context *ctx);
+
+int main(int argc, char *argv[])
+{
+	int ret;
+
+	struct setup setup;
+	ret = parse_args(&setup, argc, argv);
+	BYE_ON(ret, "syntax error\n");
+
+	int fd;
+	fd = open(argv[1], O_RDWR);
+	BYE_ON(fd < 0, "open failed: %s\n", ERRSTR);
+
+	/* configure desired image size */
+	struct v4l2_format fmt;
+	fmt.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+	fmt.fmt.pix.width = setup.width;
+	fmt.fmt.pix.height = setup.height;
+	/* format is hardcoded: draw procedures work only in 32-bit mode */
+	fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_BGR32;
+
+	ret = ioctl(fd, VIDIOC_S_FMT, &fmt);
+	BYE_ON(ret < 0, "VIDIOC_S_FMT failed: %s\n", ERRSTR);
+
+	/* update format struct to values adjusted by a driver */
+	ret = ioctl(fd, VIDIOC_G_FMT, &fmt);
+	BYE_ON(ret < 0, "VIDIOC_G_FMT failed: %s\n", ERRSTR);
+
+	/* allocate buffers */
+	struct v4l2_requestbuffers rqbufs;
+	rqbufs.count = BUFFER_CNT;
+	rqbufs.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+	rqbufs.memory = V4L2_MEMORY_MMAP;
+
+	ret = ioctl(fd, VIDIOC_REQBUFS, &rqbufs);
+	BYE_ON(ret < 0, "VIDIOC_REQBUFS failed: %s\n", ERRSTR);
+	BYE_ON(rqbufs.count < BUFFER_CNT, "failed to get %d buffers\n",
+		BUFFER_CNT);
+
+	struct buffer buffer[BUFFER_CNT];
+	/* size_t size = 4 * setup.width * setup.height; */
+
+	/* buffers initalization */
+	for (int i = 0; i < BUFFER_CNT; ++i) {
+		struct v4l2_plane plane;
+		struct v4l2_buffer buf;
+		buf.index = i;
+		buf.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+		buf.memory = V4L2_MEMORY_MMAP;
+		buf.m.planes = &plane;
+		buf.length = 1;
+		/* get buffer properties from a driver */
+		ret = ioctl(fd, VIDIOC_QUERYBUF, &buf);
+		BYE_ON(ret < 0, "VIDIOC_QUERYBUF for buffer %d failed: %s\n",
+			buf.index, ERRSTR);
+
+		buffer[i].index = i;
+		/* mmap buffer to user space */
+		buffer[i].data = mmap(NULL, plane.length, PROT_READ | PROT_WRITE,
+			MAP_SHARED, fd, plane.m.mem_offset);
+		BYE_ON(buffer[i].data == MAP_FAILED, "mmap failed: %s\n",
+			ERRSTR);
+		buffer[i].size = plane.length;
+		buffer[i].width = fmt.fmt.pix.width;
+		buffer[i].height = fmt.fmt.pix.height;
+		/* fill buffer with black */
+		for (size_t j = 0; 4 * j < buffer[i].size; ++j)
+			((uint32_t*)buffer[i].data)[j] = 0xff000000;
+	}
+
+	/* crop output area on display */
+	struct v4l2_crop crop;
+	crop.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
+	crop.c.left = setup.xoffset;
+	crop.c.top = setup.yoffset;
+	crop.c.width = setup.width;
+	crop.c.height = setup.height;
+	ret = ioctl(fd, VIDIOC_S_CROP, &crop);
+	BYE_ON(ret < 0, "VIDIOC_S_CROP failed: %s\n", ERRSTR);
+
+	struct context context;
+	context.fd = fd;
+	context.buffer = buffer;
+	context.buffer_cnt = BUFFER_CNT;
+	/* It's show-time !!! */
+	showtime(&context);
+
+	return 0;
+}
+
+int parse_args(struct setup *setup, int argc, char *argv[])
+{
+	setup->path = argv[1];
+	setup->width = atoi(argv[2]);
+	setup->height = atoi(argv[3]);
+	setup->xoffset = atoi(argv[4]);
+	setup->yoffset = atoi(argv[5]);
+	return 0;
+}
+
+double gettime(void);
+void buffer_fill(struct buffer *buf, double t);
+int queue(int fd, int index);
+int dequeue(int fd, int *index);
+
+int showtime(struct context *ctx)
+{
+	double t;
+
+	/* fill and pass all buffers to the driver */
+	for (int i = 0; i < ctx->buffer_cnt; ++i) {
+		t = gettime();
+		buffer_fill(&ctx->buffer[i], t);
+		queue(ctx->fd, i);
+	}
+	fprintf(stderr, "start\n");
+	/* start streaming */
+	int ret, type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+	ret = ioctl(ctx->fd, VIDIOC_STREAMON, &type);
+	BYE_ON(ret, "VIDIOC_STREAMON failed: %s\n", ERRSTR);
+
+	int index;
+	/* main loop, every dequeued buffer is refilled and enqueued again */
+	while (dequeue(ctx->fd, &index) == 0) {
+		t = gettime();
+		buffer_fill(&ctx->buffer[index], t);
+		queue(ctx->fd, index);
+	}
+	return 0;
+}
+
+double gettime(void)
+{
+	struct timeval tv;
+	gettimeofday(&tv, NULL);
+	double t = tv.tv_sec + 1e-6 * tv.tv_usec;
+	return t;
+}
+
+void draw_rect(struct buffer *buf, struct v4l2_rect *r, uint32_t v)
+{
+	uint32_t *ptr = buf->data;
+	ptr += buf->width * r->top + r->left;
+	for (int i = 0; i < r->height; ++i) {
+		for (int j = 0; j < r->width; ++j)
+			ptr[j] = v;
+		ptr += buf->width;
+	}
+}
+
+void prepare_rect(struct buffer *buf, struct v4l2_rect *r, double t)
+{
+	r->left = 0.8 * buf->width * (0.5 + 0.5 * sin(t));
+	r->top = 0.8 * buf->height * (0.5 + 0.5 * sin(1.41 * t));
+	r->width = 0.2 * buf->width;
+	r->height = 0.2 * buf->height;
+}
+
+void buffer_fill(struct buffer *buf, double t)
+{
+	struct v4l2_rect r;
+	prepare_rect(buf, &r, buf->t);
+	draw_rect(buf, &r, 0xff000000);
+	prepare_rect(buf, &r, t);
+	int R, G, B;
+	R = 125 + 125 * sin(3 * t);
+	G = 125 + 125 * sin(4 * t);
+	B = 125 + 125 * sin(5 * t);
+	draw_rect(buf, &r, (R << 0) | (G << 8) | (B << 16) | (0xff << 24));
+	buf->t = t;
+}
+
+int queue(int fd, int index)
+{
+	struct v4l2_buffer buf;
+	struct v4l2_plane plane;
+	memset(&buf, 0, sizeof buf);
+	memset(&plane, 0, sizeof plane);
+	buf.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+	buf.index = index;
+	buf.memory = V4L2_MEMORY_MMAP;
+	buf.m.planes = &plane;
+	buf.length = 1;
+	int ret;
+	ret = ioctl(fd, VIDIOC_QBUF, &buf);
+	BYE_ON(ret, "VIDIOC_QBUF(index = %d) failed: %s\n",
+		index, ERRSTR);
+	return 0;
+}
+
+int dequeue(int fd, int *index)
+{
+	int ret;
+	struct v4l2_buffer buf;
+	memset(&buf, 0, sizeof buf);
+	buf.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
+	buf.memory = V4L2_MEMORY_MMAP;
+	ret = ioctl(fd, VIDIOC_DQBUF, &buf);
+	BYE_ON(ret, "VIDIOC_DQBUF failed: %s\n", ERRSTR);
+	*index = buf.index;
+	return 0;
+}