Re: [RFC, libv4l]: Make libv4l2 usable on devices with complex pipeline

[Pavel Machek <pavel@ucw.cz>]

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Hi!

> > #modes: 2
> > Driver name: OMAP 3 resizer
> 
> It probably makes sense to place the driver name before #modes.

I dropped the driver for now. It served no purpose...

I got the patches to work on N900. With them (and right)

> From what I understood, the "#foo: <number>" is a tag that makes the
> parser to expect for <number> of "foo".
> 
> I would also add a first line at the beginning describing the
> version of the format, just in case we add more stuff that
> would require to change something at the format.

Ok, done.

> Except for that, it seems ok.

Good, thanks!

Here's current version of the patch. Code will need moving to
libv4l2. Would "v4l2_open_pipeline()" be suitable name to use?

Best regards,
								Pavel

diff --git a/contrib/test/sdlcam.c b/contrib/test/sdlcam.c
index cc43a10..95f85f9 100644
--- a/contrib/test/sdlcam.c
+++ b/contrib/test/sdlcam.c
@@ -8,7 +8,7 @@
    Copyright 2017 Pavel Machek, LGPL
 
    Needs sdl2, sdl2_image libraries. sudo aptitude install libsdl2-dev
-   libsdl2-image-dev on Debian systems.
+   libsdl2-image-dev libjpeg-dev on Debian systems.
 */
 
 #include <time.h>
@@ -26,6 +26,7 @@
 #include <sys/time.h>
 #include <sys/ioctl.h>
 #include <fcntl.h>
+#include <dirent.h>
 
 #include <jpeglib.h>
 
@@ -1172,11 +1173,18 @@ static void sdl_iteration(struct sdl *m)
 	}
 }
 
+static int open_complex(char *name, int v4l2_flags);
+
 static void cam_open(struct dev_info *dev, char *name)
 {
 	struct v4l2_format *fmt = &dev->fmt;
 
-	dev->fd = v4l2_open(name, O_RDWR);
+	//	dev->fd = v4l2_open(name, O_RDWR);
+	//dev->fd = open_complex("/my/tui/camera/n900.cv", 0);
+	dev->fd = open_complex("/data/pavel/g/v4l-utils/test.txt", 0);
+	//dev->fd = open(name, O_RDWR);
+	//printf("fd = %d\n", dev->fd);
+	//dev->fd = v4l2_fd_open(dev->fd, 0);
 	if (dev->fd < 0) {
 		printf("video %s open failed: %m\n", name);
 		exit(1);
@@ -1198,6 +1206,179 @@ static void cam_open(struct dev_info *dev, char *name)
 
 /* ------------------------------------------------------------------ */
 
+static void scan_devices(char **device_names, int *device_fds, int num)
+{
+	struct dirent **namelist;
+	int n;
+	char *class_v4l = "/sys/class/video4linux";
+
+	n = scandir(class_v4l, &namelist, NULL, alphasort);
+	if (n < 0) {
+		perror("scandir");
+		return;
+	}
+	
+	while (n--) {
+		if (namelist[n]->d_name[0] != '.') {
+			char filename[1024], content[1024];
+			sprintf(filename, "%s/%s/name", class_v4l, namelist[n]->d_name);
+			FILE *f = fopen(filename, "r");
+			if (!f) {
+				printf("Strange, can't open %s", filename);
+			} else {
+				fgets(content, 1024, f);
+				fclose(f);
+				printf("device %s : %s\n", namelist[n]->d_name, content);
+				int i;
+				for (i = num-1; i >=0; i--) {
+					if (!strcmp(content, device_names[i])) {
+						sprintf(filename, "/dev/%s", namelist[n]->d_name);
+						device_fds[i] = open(filename, O_RDWR);
+						if (device_fds[i] < 0) {
+							printf("Error opening %s: %m\n", filename);
+						}
+						printf("*** found match - %s %d\n", filename, device_fds[i]);
+					}
+				}
+			}
+		}
+		free(namelist[n]);
+	}
+	free(namelist);
+  
+}
+
+static int open_complex(char *name, int v4l2_flags)
+{
+#define perr(s) printf("v4l2: open_complex: " s "\n");
+#define BUF 256
+	FILE *f = fopen(name, "r");
+
+	int res = -1;
+	char buf[BUF];
+	int version, num_modes, num_devices, num_controls;
+	int dev, control;
+
+	if (!f) {
+		perr("open of .cv file failed: %m");
+		goto err;
+	}
+
+	if (fscanf(f, "Complex Video: %d\n", &version) != 1) {
+		perr(".cv file does not have required header");
+		goto close;
+	}
+
+	if (version != 0) {
+		perr(".cv file has unknown version");
+		goto close;
+	}
+  
+	if (fscanf(f, "#modes: %d\n", &num_modes) != 1) {
+		perr("could not parse modes");
+		goto close;
+	}
+
+	if (num_modes != 1) {
+		perr("only single mode is supported for now");
+		goto close;
+	}
+
+	if (fscanf(f, "Mode: %s\n", buf) != 1) {
+		perr("could not parse mode name");
+		goto close;
+	}
+
+	if (fscanf(f, " #devices: %d\n", &num_devices) != 1) {
+		perr("could not parse number of devices");
+		goto close;
+	}
+#define MAX_DEVICES 16
+	char *device_names[MAX_DEVICES] = { NULL, };
+	int device_fds[MAX_DEVICES];
+	if (num_devices > MAX_DEVICES) {
+		perr("too many devices");
+		goto close;
+	}
+  
+	for (dev = 0; dev < num_devices; dev++) {
+		int tmp;
+		if (fscanf(f, "%d: ", &tmp) != 1) {
+			perr("could not parse device");
+			goto free_devices;
+		}
+		if (tmp != dev) {
+			perr("bad device number");
+			goto free_devices;
+		}
+		fgets(buf, BUF, f);
+		printf("Device %d %d %s\n", dev, tmp, buf);
+		device_names[dev] = strdup(buf);
+		device_fds[dev] = -1;
+	}
+
+	scan_devices(device_names, device_fds, num_devices);
+
+	for (dev = 0; dev < num_devices; dev++) {
+		printf("Device %d fd %d\n", dev, device_fds[dev]);
+		if (device_fds[dev] == -1) {
+			perr("Could not open all required devices");
+			goto close_devices;
+		}
+	}
+
+	if (fscanf(f, " #controls: %d\n", &num_controls) != 1) {
+		perr("can not parse number of controls");
+		goto close_devices;
+	}
+
+	struct v4l2_controls_map *map = malloc(sizeof(struct v4l2_controls_map) +
+					       num_controls*sizeof(struct v4l2_control_map));
+
+	map->num_controls = num_controls;
+	map->num_fds = num_devices;
+	map->main_fd = device_fds[0];
+  
+	for (control = 0; control < num_controls; control++) {
+		unsigned long num;
+		int dev;
+		if (fscanf(f, "0x%lx: %d\n", &num, &dev) != 2) {
+			perr("could not parse control");
+			goto free_map;
+		}
+		if ((dev < 0) || (dev >= num_devices)) {
+			perr("device out of range");
+			goto free_map;
+		}
+		map->map[control].control = num;
+		map->map[control].fd = device_fds[dev];
+		printf("---> map: %lx %d\n", num, device_fds[dev]);
+	}
+	if (fscanf(f, "%s", buf) > 0) {
+		perr("junk at end of file");
+		goto free_map;
+	}
+
+	printf("Success, main fd is %d\n", map->main_fd);
+	res = v4l2_open_pipeline(map, v4l2_flags);
+
+	if (res < 0) {
+free_map:
+		free(map);
+close_devices:
+		for (dev = 0; dev < num_devices; dev++)
+			close(device_fds[dev]);
+	}
+free_devices:
+	for (dev = 0; dev < num_devices; dev++) {
+		free(device_names[dev]);
+	}
+close:
+	fclose(f);
+err:
+	return res;
+}
+
 
 static struct dev_info dev;
 
@@ -1206,6 +1387,8 @@ int main(void)
 	int i;
 	struct v4l2_format *fmt = &dev.fmt;
 
+	//open_complex("/my/tui/camera/n900.cv");
+
 	dtime();
 	cam_open(&dev, "/dev/video0");
 
diff --git a/lib/include/libv4l2.h b/lib/include/libv4l2.h
index ea1870d..6220dfd 100644
--- a/lib/include/libv4l2.h
+++ b/lib/include/libv4l2.h
@@ -109,6 +109,23 @@ LIBV4L_PUBLIC int v4l2_get_control(int fd, int cid);
    (note the fd is left open in this case). */
 LIBV4L_PUBLIC int v4l2_fd_open(int fd, int v4l2_flags);
 
+struct v4l2_control_map {
+	unsigned long control;
+	int fd;
+};
+
+struct v4l2_controls_map {
+	int main_fd;
+	int num_fds;
+	int num_controls;
+	struct v4l2_control_map map[];
+};
+
+LIBV4L_PUBLIC int v4l2_open_pipeline(struct v4l2_controls_map *map, int v4l2_flags);
+
+LIBV4L_PUBLIC int v4l2_get_fd_for_control(int fd, unsigned long control);
+
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
diff --git a/lib/libv4l2/libv4l2-priv.h b/lib/libv4l2/libv4l2-priv.h
index 1924c91..ebe5dad 100644
--- a/lib/libv4l2/libv4l2-priv.h
+++ b/lib/libv4l2/libv4l2-priv.h
@@ -104,6 +104,7 @@ struct v4l2_dev_info {
 	void *plugin_library;
 	void *dev_ops_priv;
 	const struct libv4l_dev_ops *dev_ops;
+	struct v4l2_controls_map *map;
 };
 
 /* From v4l2-plugin.c */
diff --git a/lib/libv4l2/libv4l2.c b/lib/libv4l2/libv4l2.c
index 2db25d1..6bb232d 100644
--- a/lib/libv4l2/libv4l2.c
+++ b/lib/libv4l2/libv4l2.c
@@ -787,6 +787,8 @@ no_capture:
 	if (index >= devices_used)
 		devices_used = index + 1;
 
+	devices[index].map = NULL;
+
 	/* Note we always tell v4lconvert to optimize src fmt selection for
 	   our default fps, the only exception is the app explicitly selecting
 	   a frame rate using the S_PARM ioctl after a S_FMT */
@@ -1056,12 +1058,47 @@ static int v4l2_s_fmt(int index, struct v4l2_format *dest_fmt)
 	return 0;
 }
 
+int v4l2_get_fd_for_control(int fd, unsigned long control)
+{
+	int index = v4l2_get_index(fd);
+	struct v4l2_controls_map *map;
+	int lo = 0;
+	int hi;
+
+	if (index < 0)
+		return fd;
+
+	map = devices[index].map;
+	if (!map)
+		return fd;
+	hi = map->num_controls;
+
+	while (lo < hi) {
+		int i = (lo + hi) / 2;
+		if (map->map[i].control == control) {
+			return map->map[i].fd;
+		}
+		if (map->map[i].control > control) {
+			hi = i;
+			continue;
+		}
+		if (map->map[i].control < control) {
+			lo = i+1;
+			continue;
+		}
+		printf("Bad: impossible condition in binary search\n");
+		exit(1);
+	}
+	return fd;
+}
+
 int v4l2_ioctl(int fd, unsigned long int request, ...)
 {
 	void *arg;
 	va_list ap;
 	int result, index, saved_err;
-	int is_capture_request = 0, stream_needs_locking = 0;
+	int is_capture_request = 0, stream_needs_locking = 0, 
+	    is_subdev_request = 0;
 
 	va_start(ap, request);
 	arg = va_arg(ap, void *);
@@ -1076,18 +1113,20 @@ int v4l2_ioctl(int fd, unsigned long int request, ...)
 	   ioctl, causing it to get sign extended, depending upon this behavior */
 	request = (unsigned int)request;
 
+	/* FIXME */
 	if (devices[index].convert == NULL)
 		goto no_capture_request;
 
 	/* Is this a capture request and do we need to take the stream lock? */
 	switch (request) {
-	case VIDIOC_QUERYCAP:
 	case VIDIOC_QUERYCTRL:
 	case VIDIOC_G_CTRL:
 	case VIDIOC_S_CTRL:
 	case VIDIOC_G_EXT_CTRLS:
-	case VIDIOC_TRY_EXT_CTRLS:
 	case VIDIOC_S_EXT_CTRLS:
+		is_subdev_request = 1;
+	case VIDIOC_QUERYCAP:
+	case VIDIOC_TRY_EXT_CTRLS:
 	case VIDIOC_ENUM_FRAMESIZES:
 	case VIDIOC_ENUM_FRAMEINTERVALS:
 		is_capture_request = 1;
@@ -1151,10 +1190,15 @@ int v4l2_ioctl(int fd, unsigned long int request, ...)
 	}
 
 	if (!is_capture_request) {
+	  int sub_fd;
 no_capture_request:
+		  sub_fd = fd;
+		if (is_subdev_request) {
+		  sub_fd = v4l2_get_fd_for_control(index, ((struct v4l2_queryctrl *) arg)->id);
+		}
 		result = devices[index].dev_ops->ioctl(
 				devices[index].dev_ops_priv,
-				fd, request, arg);
+				sub_fd, request, arg);
 		saved_err = errno;
 		v4l2_log_ioctl(request, arg, result);
 		errno = saved_err;
@@ -1782,3 +1826,28 @@ int v4l2_get_control(int fd, int cid)
 			(qctrl.maximum - qctrl.minimum) / 2) /
 		(qctrl.maximum - qctrl.minimum);
 }
+
+
+int v4l2_open_pipeline(struct v4l2_controls_map *map, int v4l2_flags)
+{
+	int index;
+	int i;
+
+	for (i=0; i<map->num_controls; i++) {
+	  printf("%lx %d\n", map->map[i].control, map->map[i].fd);
+	  if (map->map[i].fd <= 0) {
+	    printf("Bad fd in map\n");
+	    return -1;
+	  }
+	  if (i>=1 && map->map[i].control <= map->map[i-1].control) {
+	    printf("Not sorted\n");
+	    return -1;
+	  }
+	}
+
+	i = v4l2_fd_open(map->main_fd, v4l2_flags);
+	index = v4l2_get_index(map->main_fd);
+	devices[index].map = map;
+	return i;
+}
+
diff --git a/lib/libv4lconvert/control/libv4lcontrol.c b/lib/libv4lconvert/control/libv4lcontrol.c
index 59f28b1..c1e6f93 100644
--- a/lib/libv4lconvert/control/libv4lcontrol.c
+++ b/lib/libv4lconvert/control/libv4lcontrol.c
@@ -863,6 +863,7 @@ int v4lcontrol_vidioc_queryctrl(struct v4lcontrol_data *data, void *arg)
 	struct v4l2_queryctrl *ctrl = arg;
 	int retval;
 	uint32_t orig_id = ctrl->id;
+	int fd;
 
 	/* if we have an exact match return it */
 	for (i = 0; i < V4LCONTROL_COUNT; i++)
@@ -872,8 +873,9 @@ int v4lcontrol_vidioc_queryctrl(struct v4lcontrol_data *data, void *arg)
 			return 0;
 		}
 
+	fd = v4l2_get_fd_for_control(data->fd, ctrl->id);
 	/* find out what the kernel driver would respond. */
-	retval = data->dev_ops->ioctl(data->dev_ops_priv, data->fd,
+	retval = data->dev_ops->ioctl(data->dev_ops_priv, fd,
 			VIDIOC_QUERYCTRL, arg);
 
 	if ((data->priv_flags & V4LCONTROL_SUPPORTS_NEXT_CTRL) &&
@@ -903,6 +905,7 @@ int v4lcontrol_vidioc_g_ctrl(struct v4lcontrol_data *data, void *arg)
 {
 	int i;
 	struct v4l2_control *ctrl = arg;
+	int fd;
 
 	for (i = 0; i < V4LCONTROL_COUNT; i++)
 		if ((data->controls & (1 << i)) &&
@@ -911,7 +914,8 @@ int v4lcontrol_vidioc_g_ctrl(struct v4lcontrol_data *data, void *arg)
 			return 0;
 		}
 
-	return data->dev_ops->ioctl(data->dev_ops_priv, data->fd,
+	fd = v4l2_get_fd_for_control(data->fd, ctrl->id);
+	return data->dev_ops->ioctl(data->dev_ops_priv, fd,
 			VIDIOC_G_CTRL, arg);
 }
 
@@ -994,6 +998,7 @@ int v4lcontrol_vidioc_s_ctrl(struct v4lcontrol_data *data, void *arg)
 {
 	int i;
 	struct v4l2_control *ctrl = arg;
+	int fd;
 
 	for (i = 0; i < V4LCONTROL_COUNT; i++)
 		if ((data->controls & (1 << i)) &&
@@ -1008,7 +1013,8 @@ int v4lcontrol_vidioc_s_ctrl(struct v4lcontrol_data *data, void *arg)
 			return 0;
 		}
 
-	return data->dev_ops->ioctl(data->dev_ops_priv, data->fd,
+	fd = v4l2_get_fd_for_control(data->fd, ctrl->id);
+	return data->dev_ops->ioctl(data->dev_ops_priv, fd,
 			VIDIOC_S_CTRL, arg);
 }
 


-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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