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

[Pavel Machek <pavel@ucw.cz>]

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Hi!

> I really don't want to add functions for this to libv4l2. That's just a
> quick hack. The real solution is to parse this from a config
> file. But

No, this is not a quick hack. These are functions that will eventually
be used by the config parser. (Oh and they allow me to use camera on
complex hardware, but...).

Hmm, I have mentioned that already. See quoted text below. 

> that is a lot more work and it is something that needs to be designed
> properly.
> 
> And that requires someone to put in the time and effort...

Which is what I'm trying to do. But some cooperation from your side is
needed, too. I acknowledged some kind of parser is needed. I can
do that. Are you willing to cooperate?

But I need your feedback on the parts below. We can bikeshed about the
parser later.

Do they look acceptable? Did I hook up right functions in acceptable
way?

If so, yes, I can proceed with parser.

Best regards,
							Pavel


> > ...so you can use it on complex devices. Tested on my N900.
> > 
> > I guess later helper would be added that would parse some kind of
> > descritption file and do open_pipeline(). But.. lets solve that
> > next. In the first place, it would be nice to have libv4l2 usable on
> > complex devices.
> > 
> > Best regards,
> > 							Pavel
> > Signed-off-by: Pavel Machek <pavel@ucw.cz>
> > 
> > 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..b3ae70b 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 +1058,39 @@ 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 = devices[index].map;
> > +	int lo = 0;
> > +	int hi = map->num_controls;
> > +
> > +	while (lo < hi) {
> > +		int i = (lo + hi) / 2;
> > +		if (map->map[i].control == control) {
> > +			return map->map[i].fd + 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 +1105,20 @@ 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 +1182,15 @@ 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 +1818,28 @@ 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;
> > +	  }
> > +	}
> > +
> > +	v4l2_fd_open(map->main_fd, v4l2_flags);
> > +	index = v4l2_get_index(map->main_fd);
> > +	devices[index].map = map;
> > +	return 0;
> > +}
> > +
> > diff --git a/lib/libv4lconvert/control/libv4lcontrol.c b/lib/libv4lconvert/control/libv4lcontrol.c
> > index 1e784ed..1963e7e 100644
> > --- a/lib/libv4lconvert/control/libv4lcontrol.c
> > +++ b/lib/libv4lconvert/control/libv4lcontrol.c
> > @@ -865,6 +865,7 @@ 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++)
> > @@ -874,8 +875,9 @@ 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) &&
> > @@ -905,6 +907,7 @@ 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)) &&
> > @@ -913,7 +916,8 @@ 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);
> >  }
> >  
> > @@ -996,6 +1000,7 @@ 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)) &&
> > @@ -1010,7 +1015,8 @@ 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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