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Date: Thu, 19 Jul 2018 22:53:44 +0200
From: Pavel Machek <pavel@....cz>
To: pali.rohar@...il.com, sre@...nel.org,
kernel list <linux-kernel@...r.kernel.org>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
linux-omap@...r.kernel.org, tony@...mide.com, khilman@...nel.org,
aaro.koskinen@....fi, ivo.g.dimitrov.75@...il.com,
patrikbachan@...il.com, serge@...lyn.com, abcloriens@...il.com,
clayton@...ftyguy.net, martijn@...xit.nl,
sakari.ailus@...ux.intel.com,
Filip Matijević <filip.matijevic.pz@...il.com>,
mchehab@...pensource.com, sakari.ailus@....fi,
linux-media@...r.kernel.org, hans.verkuil@...co.com
Subject: Re: [PATCH, libv4l]: Make libv4l2 usable on devices with complex
pipeline
On Sun 2018-07-08 23:32:58, Pavel Machek wrote:
>
> Add support for opening multiple devices in v4l2_open(), and for
> mapping controls between devices.
>
> This is necessary for complex devices, such as Nokia N900.
>
> Signed-off-by: Pavel Machek <pavel@....cz>
Ping?
There's a lot of work to do on libv4l2... timely patch handling would
be nice.
> diff --git a/lib/include/libv4l2.h b/lib/include/libv4l2.h
> index ea1870d..a0ec0a9 100644
> --- a/lib/include/libv4l2.h
> +++ b/lib/include/libv4l2.h
> @@ -58,6 +58,10 @@ LIBV4L_PUBLIC extern FILE *v4l2_log_file;
> invalid memory address will not lead to failure with errno being EFAULT,
> as it would with a real ioctl, but will cause libv4l2 to break, and you
> get to keep both pieces.
> +
> + You can open complex pipelines by passing ".cv" file with pipeline
> + description to v4l2_open(). libv4l2 will open all the required
> + devices automatically in that case.
> */
>
> LIBV4L_PUBLIC int v4l2_open(const char *file, int oflag, ...);
> diff --git a/lib/libv4l2/libv4l2-priv.h b/lib/libv4l2/libv4l2-priv.h
> index 1924c91..1ee697a 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 */
> @@ -130,4 +131,20 @@ static inline void v4l2_plugin_cleanup(void *plugin_lib, void *plugin_priv,
> extern const char *v4l2_ioctls[];
> void v4l2_log_ioctl(unsigned long int request, void *arg, int result);
>
> +
> +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[];
> +};
> +
> +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);
> +
> #endif
> diff --git a/lib/libv4l2/libv4l2.c b/lib/libv4l2/libv4l2.c
> index 2db25d1..ac430f0 100644
> --- a/lib/libv4l2/libv4l2.c
> +++ b/lib/libv4l2/libv4l2.c
> @@ -70,6 +70,8 @@
> #include <sys/types.h>
> #include <sys/mman.h>
> #include <sys/stat.h>
> +#include <dirent.h>
> +
> #include "libv4l2.h"
> #include "libv4l2-priv.h"
> #include "libv4l-plugin.h"
> @@ -618,6 +620,8 @@ static void v4l2_update_fps(int index, struct v4l2_streamparm *parm)
> devices[index].fps = 0;
> }
>
> +static int v4l2_open_complex(int fd, int v4l2_flags);
> +
> int v4l2_open(const char *file, int oflag, ...)
> {
> int fd;
> @@ -641,6 +645,21 @@ int v4l2_open(const char *file, int oflag, ...)
> if (fd == -1)
> return fd;
>
> + int len = strlen(file);
> + char *end = ".cv";
> + int len2 = strlen(end);
> + if ((len > len2) && (!strcmp(file + len - len2, end))) {
> + /* .cv extension */
> + struct stat sb;
> +
> + if (fstat(fd, &sb) == 0) {
> + if ((sb.st_mode & S_IFMT) == S_IFREG) {
> + return v4l2_open_complex(fd, 0);
> + }
> + }
> +
> + }
> +
> if (v4l2_fd_open(fd, 0) == -1) {
> int saved_err = errno;
>
> @@ -787,6 +806,8 @@ 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 +1077,47 @@ 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 +1132,19 @@ int v4l2_ioctl(int fd, unsigned long int request, ...)
> ioctl, causing it to get sign extended, depending upon this behavior */
> request = (unsigned int)request;
>
> 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 +1209,15 @@ 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 +1845,194 @@ 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++) {
> + if (map->map[i].fd <= 0) {
> + V4L2_LOG_ERR("v4l2_open_pipeline: Bad fd in map.\n");
> + return -1;
> + }
> + if (i>=1 && map->map[i].control <= map->map[i-1].control) {
> + V4L2_LOG_ERR("v4l2_open_pipeline: Controls 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;
> +}
> +
> +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);
> +
> + 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) {
> + V4L2_LOG_ERR("Error opening %s: %m\n", filename);
> + }
> + }
> + }
> + }
> + }
> + free(namelist[n]);
> + }
> + free(namelist);
> +
> +}
> +
> +static int v4l2_open_complex(int fd, int v4l2_flags)
> +{
> +#define perr(s) V4L2_LOG_ERR("open_complex: " s "\n")
> +#define BUF 256
> + FILE *f = fdopen(fd, "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);
> + device_names[dev] = strdup(buf);
> + device_fds[dev] = -1;
> + }
> +
> + scan_devices(device_names, device_fds, num_devices);
> +
> + for (dev = 0; dev < num_devices; 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];
> + }
> + if (fscanf(f, "%s", buf) > 0) {
> + perr("junk at end of file");
> + goto free_map;
> + }
> +
> + 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;
> +}
> +
> 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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