diff options
| -rw-r--r-- | Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst | 46 | ||||
| -rw-r--r-- | drivers/media/v4l2-core/v4l2-ioctl.c | 4 | ||||
| -rw-r--r-- | drivers/media/v4l2-core/v4l2-subdev.c | 12 | ||||
| -rw-r--r-- | include/media/v4l2-subdev.h | 2 | ||||
| -rw-r--r-- | include/uapi/linux/v4l2-subdev.h | 10 |
5 files changed, 49 insertions, 25 deletions
diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst index 26b5004bfe6d..cbd9370006b6 100644 --- a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst @@ -43,23 +43,38 @@ The routing configuration determines the flows of data inside an entity. Drivers report their current routing tables using the ``VIDIOC_SUBDEV_G_ROUTING`` ioctl and application may enable or disable routes with the ``VIDIOC_SUBDEV_S_ROUTING`` ioctl, by adding or removing routes and -setting or clearing flags of the ``flags`` field of a -struct :c:type:`v4l2_subdev_route`. +setting or clearing flags of the ``flags`` field of a struct +:c:type:`v4l2_subdev_route`. -All stream configurations are reset when ``VIDIOC_SUBDEV_S_ROUTING`` is called. This -means that the userspace must reconfigure all streams after calling the ioctl -with e.g. ``VIDIOC_SUBDEV_S_FMT``. +All stream configurations are reset when ``VIDIOC_SUBDEV_S_ROUTING`` is called. +This means that the userspace must reconfigure all stream formats and selections +after calling the ioctl with e.g. ``VIDIOC_SUBDEV_S_FMT``. Only subdevices which have both sink and source pads can support routing. -When inspecting routes through ``VIDIOC_SUBDEV_G_ROUTING`` and the application -provided ``num_routes`` is not big enough to contain all the available routes -the subdevice exposes, drivers return the ENOSPC error code and adjust the -value of the ``num_routes`` field. Application should then reserve enough memory -for all the route entries and call ``VIDIOC_SUBDEV_G_ROUTING`` again. - -On a successful ``VIDIOC_SUBDEV_G_ROUTING`` call the driver updates the -``num_routes`` field to reflect the actual number of routes returned. +The ``len_routes`` field indicates the number of routes that can fit in the +``routes`` array allocated by userspace. It is set by applications for both +ioctls to indicate how many routes the kernel can return, and is never modified +by the kernel. + +The ``num_routes`` field indicates the number of routes in the routing +table. For ``VIDIOC_SUBDEV_S_ROUTING``, it is set by userspace to the number of +routes that the application stored in the ``routes`` array. For both ioctls, it +is returned by the kernel and indicates how many routes are stored in the +subdevice routing table. This may be smaller or larger than the value of +``num_routes`` set by the application for ``VIDIOC_SUBDEV_S_ROUTING``, as +drivers may adjust the requested routing table. + +The kernel can return a ``num_routes`` value larger than ``len_routes`` from +both ioctls. This indicates thare are more routes in the routing table than fits +the ``routes`` array. In this case, the ``routes`` array is filled by the kernel +with the first ``len_routes`` entries of the subdevice routing table. This is +not considered to be an error, and the ioctl call succeeds. If the applications +wants to retrieve the missing routes, it can issue a new +``VIDIOC_SUBDEV_G_ROUTING`` call with a large enough ``routes`` array. + +``VIDIOC_SUBDEV_S_ROUTING`` may return more routes than the user provided in +``num_routes`` field due to e.g. hardware properties. .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.7cm}| @@ -74,6 +89,9 @@ On a successful ``VIDIOC_SUBDEV_G_ROUTING`` call the driver updates the - ``which`` - Routing table to be accessed, from enum :ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`. + * - __u32 + - ``len_routes`` + - The length of the array (as in memory reserved for the array) * - struct :c:type:`v4l2_subdev_route` - ``routes[]`` - Array of struct :c:type:`v4l2_subdev_route` entries @@ -81,7 +99,7 @@ On a successful ``VIDIOC_SUBDEV_G_ROUTING`` call the driver updates the - ``num_routes`` - Number of entries of the routes array * - __u32 - - ``reserved``\ [5] + - ``reserved``\ [11] - Reserved for future extensions. Applications and drivers must set the array to zero. diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c index 0260acef97d2..aab671fae45b 100644 --- a/drivers/media/v4l2-core/v4l2-ioctl.c +++ b/drivers/media/v4l2-core/v4l2-ioctl.c @@ -3201,13 +3201,13 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size, case VIDIOC_SUBDEV_S_ROUTING: { struct v4l2_subdev_routing *routing = parg; - if (routing->num_routes > 256) + if (routing->len_routes > 256) return -E2BIG; *user_ptr = u64_to_user_ptr(routing->routes); *kernel_ptr = (void **)&routing->routes; *array_size = sizeof(struct v4l2_subdev_route) - * routing->num_routes; + * routing->len_routes; ret = 1; break; } diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index 779583447eac..b565f202df67 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -960,14 +960,10 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, krouting = &state->routing; - if (routing->num_routes < krouting->num_routes) { - routing->num_routes = krouting->num_routes; - return -ENOSPC; - } - memcpy((struct v4l2_subdev_route *)(uintptr_t)routing->routes, krouting->routes, - krouting->num_routes * sizeof(*krouting->routes)); + min(krouting->num_routes, routing->len_routes) * + sizeof(*krouting->routes)); routing->num_routes = krouting->num_routes; return 0; @@ -989,6 +985,9 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, if (routing->which != V4L2_SUBDEV_FORMAT_TRY && ro_subdev) return -EPERM; + if (routing->num_routes > routing->len_routes) + return -EINVAL; + memset(routing->reserved, 0, sizeof(routing->reserved)); for (i = 0; i < routing->num_routes; ++i) { @@ -1015,6 +1014,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg, } krouting.num_routes = routing->num_routes; + krouting.len_routes = routing->len_routes; krouting.routes = routes; return v4l2_subdev_call(sd, pad, set_routing, state, diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index e22c50ce7e05..e30c463d90e5 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -714,12 +714,14 @@ struct v4l2_subdev_stream_configs { /** * struct v4l2_subdev_krouting - subdev routing table * + * @len_routes: length of routes array, in routes * @num_routes: number of routes * @routes: &struct v4l2_subdev_route * * This structure contains the routing table for a subdev. */ struct v4l2_subdev_krouting { + unsigned int len_routes; unsigned int num_routes; struct v4l2_subdev_route *routes; }; diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h index 81a24bd38003..2347e266cf75 100644 --- a/include/uapi/linux/v4l2-subdev.h +++ b/include/uapi/linux/v4l2-subdev.h @@ -228,15 +228,19 @@ struct v4l2_subdev_route { * struct v4l2_subdev_routing - Subdev routing information * * @which: configuration type (from enum v4l2_subdev_format_whence) - * @num_routes: the total number of routes in the routes array + * @len_routes: the length of the routes array, in routes; set by the user, not + * modified by the kernel * @routes: pointer to the routes array + * @num_routes: the total number of routes, possibly more than fits in the + * routes array * @reserved: drivers and applications must zero this array */ struct v4l2_subdev_routing { __u32 which; - __u32 num_routes; + __u32 len_routes; __u64 routes; - __u32 reserved[6]; + __u32 num_routes; + __u32 reserved[11]; }; /* |