Hi Sakari, Laurent, Niklas,
(another) quick question, but a different one :)
On Wed, Jan 16, 2019 at 01:51:45AM +0200, Laurent Pinchart wrote:
> Hi Niklas,
>
> Thank you for the patch.
>
> On Fri, Nov 02, 2018 at 12:31:30AM +0100, Niklas Söderlund wrote:
> > From: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
> >
> > - Add sink and source streams for multiplexed links
> > - Copy the argument back in case of an error. This is needed to let the
> > caller know the number of routes.
> >
> > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> > Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> > ---
> > drivers/media/v4l2-core/v4l2-ioctl.c | 20 +++++++++++++-
> > drivers/media/v4l2-core/v4l2-subdev.c | 28 +++++++++++++++++++
> > include/media/v4l2-subdev.h | 7 +++++
> > include/uapi/linux/v4l2-subdev.h | 40 +++++++++++++++++++++++++++
>
> Missing documentation :-(
>
> > 4 files changed, 94 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> > index 7de041bae84fb2f2..40406acb51ec0906 100644
> > --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> > +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> > @@ -19,6 +19,7 @@
> > #include <linux/kernel.h>
> > #include <linux/version.h>
> >
> > +#include <linux/v4l2-subdev.h>
> > #include <linux/videodev2.h>
> >
> > #include <media/v4l2-common.h>
> > @@ -2924,6 +2925,23 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
> > }
> > break;
> > }
> > +
> > + case VIDIOC_SUBDEV_G_ROUTING:
> > + case VIDIOC_SUBDEV_S_ROUTING: {
> > + struct v4l2_subdev_routing *route = parg;
> > +
> > + if (route->num_routes > 0) {
> > + if (route->num_routes > 256)
> > + return -EINVAL;
> > +
> > + *user_ptr = (void __user *)route->routes;
> > + *kernel_ptr = (void *)&route->routes;
> > + *array_size = sizeof(struct v4l2_subdev_route)
> > + * route->num_routes;
> > + ret = 1;
> > + }
> > + break;
> > + }
> > }
> >
> > return ret;
> > @@ -3033,7 +3051,7 @@ video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
> > * Some ioctls can return an error, but still have valid
> > * results that must be returned.
> > */
> > - if (err < 0 && !always_copy)
> > + if (err < 0 && !always_copy && cmd != VIDIOC_SUBDEV_G_ROUTING)
>
> This seems like a hack. Shouldn't VIDIOC_SUBDEV_G_ROUTING set
> always_copy instead ?
>
> > goto out;
> >
> > out_array_args:
> > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> > index 792f41dffe2329b9..1d3b37cf548fa533 100644
> > --- a/drivers/media/v4l2-core/v4l2-subdev.c
> > +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> > @@ -516,7 +516,35 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
> >
> > case VIDIOC_SUBDEV_QUERYSTD:
> > return v4l2_subdev_call(sd, video, querystd, arg);
> > +
> > + case VIDIOC_SUBDEV_G_ROUTING:
> > + return v4l2_subdev_call(sd, pad, get_routing, arg);
> > +
> > + case VIDIOC_SUBDEV_S_ROUTING: {
> > + struct v4l2_subdev_routing *route = arg;
> > + unsigned int i;
> > +
> > + if (route->num_routes > sd->entity.num_pads)
> > + return -EINVAL;
> > +
> > + for (i = 0; i < route->num_routes; ++i) {
How have you envisioned the number of routes to be negotiated with
applications? I'm writing the documentation for this ioctl, and I
would like to insert this part as well.
Would a model like the one implemented in G_TOPOLOGY work in your
opinion? In my understanding, at the moment applications do not have a
way to reserve a known number of routes entries, but would likely
reserve 'enough(tm)' (ie 256) and pass them to the G_ROUTING ioctl that the
first time will likely adjust the number of num_routes and return -ENOSPC.
Wouldn't it work to make the IOCTL behave in a way that it
expects the first call to be performed with (num_routes == 0) and no routes
entries reserved, and just adjust 'num_routes' in that case?
So that applications should call G_ROUTING a first time with
num_routes = 0, get back the number of routes entries, reserve memory
for them, and then call G_ROUTING again to have the entries populated
by the driver. Do you have different ideas or was this the intended
behavior already?
Thanks
j
> > + unsigned int sink = route->routes[i].sink_pad;
> > + unsigned int source = route->routes[i].source_pad;
> > + struct media_pad *pads = sd->entity.pads;
> > +
> > + if (sink >= sd->entity.num_pads ||
> > + source >= sd->entity.num_pads)
> > + return -EINVAL;
> > +
> > + if (!(pads[sink].flags & MEDIA_PAD_FL_SINK) ||
> > + !(pads[source].flags & MEDIA_PAD_FL_SOURCE))
> > + return -EINVAL;
> > + }
> > +
> > + return v4l2_subdev_call(sd, pad, set_routing, route);
> > + }
> > #endif
> > +
> > default:
> > return v4l2_subdev_call(sd, core, ioctl, cmd, arg);
> > }
> > diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> > index 9102d6ca566e01f2..5acaeeb9b3cacefa 100644
> > --- a/include/media/v4l2-subdev.h
> > +++ b/include/media/v4l2-subdev.h
> > @@ -679,6 +679,9 @@ struct v4l2_subdev_pad_config {
> > *
> > * @set_frame_desc: set the low level media bus frame parameters, @fd array
> > * may be adjusted by the subdev driver to device capabilities.
> > + *
> > + * @get_routing: callback for VIDIOC_SUBDEV_G_ROUTING IOCTL handler.
> > + * @set_routing: callback for VIDIOC_SUBDEV_S_ROUTING IOCTL handler.
>
> Please define the purpose of those operations instead of just pointing
> to the userspace API.
>
> > */
> > struct v4l2_subdev_pad_ops {
> > int (*init_cfg)(struct v4l2_subdev *sd,
> > @@ -719,6 +722,10 @@ struct v4l2_subdev_pad_ops {
> > struct v4l2_mbus_frame_desc *fd);
> > int (*set_frame_desc)(struct v4l2_subdev *sd, unsigned int pad,
> > struct v4l2_mbus_frame_desc *fd);
> > + int (*get_routing)(struct v4l2_subdev *sd,
> > + struct v4l2_subdev_routing *route);
> > + int (*set_routing)(struct v4l2_subdev *sd,
> > + struct v4l2_subdev_routing *route);
> > };
> >
> > /**
> > diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
> > index 03970ce3074193e6..af069bfb10ca23a5 100644
> > --- a/include/uapi/linux/v4l2-subdev.h
> > +++ b/include/uapi/linux/v4l2-subdev.h
> > @@ -155,6 +155,44 @@ struct v4l2_subdev_selection {
> > __u32 reserved[8];
> > };
> >
> > +#define V4L2_SUBDEV_ROUTE_FL_ACTIVE (1 << 0)
> > +#define V4L2_SUBDEV_ROUTE_FL_IMMUTABLE (1 << 1)
> > +
> > +/**
> > + * struct v4l2_subdev_route - A signal route inside a subdev
> > + * @sink_pad: the sink pad
> > + * @sink_stream: the sink stream
> > + * @source_pad: the source pad
> > + * @source_stream: the source stream
>
> At this point in the series there's no concept of multiplexed streams,
> so the two fields don't make sense. You may want to reorder patches, or
> split this in two.
>
> > + * @flags: route flags:
> > + *
> > + * V4L2_SUBDEV_ROUTE_FL_ACTIVE: Is the stream in use or not? An
> > + * active stream will start when streaming is enabled on a video
> > + * node. Set by the user.
>
> This is very confusing as "stream" isn't defined. The documentation
> needs a rewrite with more details.
>
> > + *
> > + * V4L2_SUBDEV_ROUTE_FL_IMMUTABLE: Is the stream immutable, i.e.
> > + * can it be activated and inactivated? Set by the driver.
> > + */
> > +struct v4l2_subdev_route {
> > + __u32 sink_pad;
> > + __u32 sink_stream;
> > + __u32 source_pad;
> > + __u32 source_stream;
> > + __u32 flags;
> > + __u32 reserved[5];
> > +};
> > +
> > +/**
> > + * struct v4l2_subdev_routing - Routing information
> > + * @routes: the routes array
> > + * @num_routes: the total number of routes in the routes array
> > + */
> > +struct v4l2_subdev_routing {
> > + struct v4l2_subdev_route *routes;
>
> Missing __user ?
>
> > + __u32 num_routes;
> > + __u32 reserved[5];
> > +};
> > +
> > /* Backwards compatibility define --- to be removed */
> > #define v4l2_subdev_edid v4l2_edid
> >
> > @@ -181,5 +219,7 @@ struct v4l2_subdev_selection {
> > #define VIDIOC_SUBDEV_ENUM_DV_TIMINGS _IOWR('V', 98, struct v4l2_enum_dv_timings)
> > #define VIDIOC_SUBDEV_QUERY_DV_TIMINGS _IOR('V', 99, struct v4l2_dv_timings)
> > #define VIDIOC_SUBDEV_DV_TIMINGS_CAP _IOWR('V', 100, struct v4l2_dv_timings_cap)
> > +#define VIDIOC_SUBDEV_G_ROUTING _IOWR('V', 38, struct v4l2_subdev_routing)
> > +#define VIDIOC_SUBDEV_S_ROUTING _IOWR('V', 39, struct v4l2_subdev_routing)
> >
> > #endif
> > --
> > 2.19.1
> >
>
> --
> Regards,
>
> Laurent Pinchart
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