[libcamera-devel,v4,4/5] v4l2-subdev: add VIDIOC_SUBDEV_QUERYCAP ioctl

Message ID 20200418103216.140572-5-jacopo@jmondi.org
State Superseded
Headers show
Series
  • media: Register read-only sub-dev devnode
Related show

Commit Message

Jacopo Mondi April 18, 2020, 10:32 a.m. UTC
From: Hans Verkuil <hans.verkuil@cisco.com>

While normal video/radio/vbi/swradio nodes have a proper QUERYCAP ioctl
that apps can call to determine that it is indeed a V4L2 device, there
is currently no equivalent for v4l-subdev nodes. Adding this ioctl will
solve that, and it will allow utilities like v4l2-compliance to be used
with these devices as well.

SUBDEV_QUERYCAP currently returns the version and subdev_caps of the
subdevice. Define as the initial set of subdev_caps the read-only or
read/write flags, to signal to userspace which set of IOCTLs are
available on the subdevice.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
---
 drivers/media/v4l2-core/v4l2-subdev.c | 12 ++++++++++++
 include/uapi/linux/v4l2-subdev.h      | 15 +++++++++++++++
 2 files changed, 27 insertions(+)

Comments

kernel test robot April 21, 2020, 4:58 a.m. UTC | #1
Hi Jacopo,

I love your patch! Yet something to improve:

[auto build test ERROR on linuxtv-media/master]
[also build test ERROR on linus/master v5.7-rc2 next-20200420]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Jacopo-Mondi/media-Register-read-only-sub-dev-devnode/20200421-053419
base:   git://linuxtv.org/media_tree.git master
config: arm-bcm2835_defconfig (attached as .config)
compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project a9b137f9ffba8cb25dfd7dd1fb613e8aac121b37)
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/media/v4l2-core/v4l2-subdev.c:345:23: error: use of undeclared identifier 'ro_subdev'
                   cap->subdev_caps |= ro_subdev ? V4L2_SUBDEV_CAP_RO_SUBDEV
                                       ^
   1 error generated.

vim +/ro_subdev +345 drivers/media/v4l2-core/v4l2-subdev.c

   327	
   328	static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
   329	{
   330		struct video_device *vdev = video_devdata(file);
   331		struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
   332		struct v4l2_fh *vfh = file->private_data;
   333	#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
   334		struct v4l2_subdev_fh *subdev_fh = to_v4l2_subdev_fh(vfh);
   335		bool ro_subdev = test_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags);
   336	#endif
   337		int rval;
   338	
   339		switch (cmd) {
   340		case VIDIOC_SUBDEV_QUERYCAP: {
   341			struct v4l2_subdev_capability *cap = arg;
   342	
   343			memset(cap, 0, sizeof(*cap));
   344			cap->version = LINUX_VERSION_CODE;
 > 345			cap->subdev_caps |= ro_subdev ? V4L2_SUBDEV_CAP_RO_SUBDEV
   346						      : V4L2_SUBDEV_CAP_RW_SUBDEV;
   347	
   348			return 0;
   349		}
   350	
   351		case VIDIOC_QUERYCTRL:
   352			/*
   353			 * TODO: this really should be folded into v4l2_queryctrl (this
   354			 * currently returns -EINVAL for NULL control handlers).
   355			 * However, v4l2_queryctrl() is still called directly by
   356			 * drivers as well and until that has been addressed I believe
   357			 * it is safer to do the check here. The same is true for the
   358			 * other control ioctls below.
   359			 */
   360			if (!vfh->ctrl_handler)
   361				return -ENOTTY;
   362			return v4l2_queryctrl(vfh->ctrl_handler, arg);
   363	
   364		case VIDIOC_QUERY_EXT_CTRL:
   365			if (!vfh->ctrl_handler)
   366				return -ENOTTY;
   367			return v4l2_query_ext_ctrl(vfh->ctrl_handler, arg);
   368	
   369		case VIDIOC_QUERYMENU:
   370			if (!vfh->ctrl_handler)
   371				return -ENOTTY;
   372			return v4l2_querymenu(vfh->ctrl_handler, arg);
   373	
   374		case VIDIOC_G_CTRL:
   375			if (!vfh->ctrl_handler)
   376				return -ENOTTY;
   377			return v4l2_g_ctrl(vfh->ctrl_handler, arg);
   378	
   379		case VIDIOC_S_CTRL:
   380			if (!vfh->ctrl_handler)
   381				return -ENOTTY;
   382			return v4l2_s_ctrl(vfh, vfh->ctrl_handler, arg);
   383	
   384		case VIDIOC_G_EXT_CTRLS:
   385			if (!vfh->ctrl_handler)
   386				return -ENOTTY;
   387			return v4l2_g_ext_ctrls(vfh->ctrl_handler,
   388						vdev, sd->v4l2_dev->mdev, arg);
   389	
   390		case VIDIOC_S_EXT_CTRLS:
   391			if (!vfh->ctrl_handler)
   392				return -ENOTTY;
   393			return v4l2_s_ext_ctrls(vfh, vfh->ctrl_handler,
   394						vdev, sd->v4l2_dev->mdev, arg);
   395	
   396		case VIDIOC_TRY_EXT_CTRLS:
   397			if (!vfh->ctrl_handler)
   398				return -ENOTTY;
   399			return v4l2_try_ext_ctrls(vfh->ctrl_handler,
   400						  vdev, sd->v4l2_dev->mdev, arg);
   401	
   402		case VIDIOC_DQEVENT:
   403			if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS))
   404				return -ENOIOCTLCMD;
   405	
   406			return v4l2_event_dequeue(vfh, arg, file->f_flags & O_NONBLOCK);
   407	
   408		case VIDIOC_DQEVENT_TIME32: {
   409			struct v4l2_event_time32 *ev32 = arg;
   410			struct v4l2_event ev = { };
   411	
   412			if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS))
   413				return -ENOIOCTLCMD;
   414	
   415			rval = v4l2_event_dequeue(vfh, &ev, file->f_flags & O_NONBLOCK);
   416	
   417			*ev32 = (struct v4l2_event_time32) {
   418				.type		= ev.type,
   419				.pending	= ev.pending,
   420				.sequence	= ev.sequence,
   421				.timestamp.tv_sec  = ev.timestamp.tv_sec,
   422				.timestamp.tv_nsec = ev.timestamp.tv_nsec,
   423				.id		= ev.id,
   424			};
   425	
   426			memcpy(&ev32->u, &ev.u, sizeof(ev.u));
   427			memcpy(&ev32->reserved, &ev.reserved, sizeof(ev.reserved));
   428	
   429			return rval;
   430		}
   431	
   432		case VIDIOC_SUBSCRIBE_EVENT:
   433			return v4l2_subdev_call(sd, core, subscribe_event, vfh, arg);
   434	
   435		case VIDIOC_UNSUBSCRIBE_EVENT:
   436			return v4l2_subdev_call(sd, core, unsubscribe_event, vfh, arg);
   437	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Sakari Ailus April 21, 2020, 9:49 p.m. UTC | #2
Hi Jacopo,

Thanks for the patch.

On Sat, Apr 18, 2020 at 12:32:15PM +0200, Jacopo Mondi wrote:
> From: Hans Verkuil <hans.verkuil@cisco.com>
> 
> While normal video/radio/vbi/swradio nodes have a proper QUERYCAP ioctl
> that apps can call to determine that it is indeed a V4L2 device, there
> is currently no equivalent for v4l-subdev nodes. Adding this ioctl will
> solve that, and it will allow utilities like v4l2-compliance to be used
> with these devices as well.
> 
> SUBDEV_QUERYCAP currently returns the version and subdev_caps of the
> subdevice. Define as the initial set of subdev_caps the read-only or
> read/write flags, to signal to userspace which set of IOCTLs are
> available on the subdevice.
> 
> Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 12 ++++++++++++
>  include/uapi/linux/v4l2-subdev.h      | 15 +++++++++++++++
>  2 files changed, 27 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 1dc263c2ca0a..ca0aa54429c5 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -15,6 +15,7 @@
>  #include <linux/types.h>
>  #include <linux/videodev2.h>
>  #include <linux/export.h>
> +#include <linux/version.h>
>  
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-device.h>
> @@ -336,6 +337,17 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  	int rval;
>  
>  	switch (cmd) {
> +	case VIDIOC_SUBDEV_QUERYCAP: {
> +		struct v4l2_subdev_capability *cap = arg;
> +
> +		memset(cap, 0, sizeof(*cap));
> +		cap->version = LINUX_VERSION_CODE;
> +		cap->subdev_caps |= ro_subdev ? V4L2_SUBDEV_CAP_RO_SUBDEV
> +					      : V4L2_SUBDEV_CAP_RW_SUBDEV;
> +
> +		return 0;
> +	}
> +
>  	case VIDIOC_QUERYCTRL:
>  		/*
>  		 * TODO: this really should be folded into v4l2_queryctrl (this
> diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
> index 03970ce30741..0886f88be193 100644
> --- a/include/uapi/linux/v4l2-subdev.h
> +++ b/include/uapi/linux/v4l2-subdev.h
> @@ -155,9 +155,24 @@ struct v4l2_subdev_selection {
>  	__u32 reserved[8];
>  };
>  
> +/**
> + * struct v4l2_subdev_capability - subdev capabilities
> + * @device_caps: the subdev capabilities, see V4L2_SUBDEV_CAP_*.
> + */
> +struct v4l2_subdev_capability {
> +	__u32 version;
> +	__u32 subdev_caps;

No reserved fields? Is the intent to extend this later on based on the size
of the IOCTL argument?

> +};
> +
> +/* The v4l2 sub-device video device node is registered in read-only mode. */
> +#define V4L2_SUBDEV_CAP_RO_SUBDEV		(1 << 0)

1U << 0

> +/* The v4l2 sub-device video device node is registered in read/write mode. */
> +#define V4L2_SUBDEV_CAP_RW_SUBDEV		(1 << 1)

1U << 1

> +
>  /* Backwards compatibility define --- to be removed */
>  #define v4l2_subdev_edid v4l2_edid
>  
> +#define VIDIOC_SUBDEV_QUERYCAP			_IOR('V',  0, struct v4l2_subdev_capability)
>  #define VIDIOC_SUBDEV_G_FMT			_IOWR('V',  4, struct v4l2_subdev_format)
>  #define VIDIOC_SUBDEV_S_FMT			_IOWR('V',  5, struct v4l2_subdev_format)
>  #define VIDIOC_SUBDEV_G_FRAME_INTERVAL		_IOWR('V', 21, struct v4l2_subdev_frame_interval)
Laurent Pinchart April 21, 2020, 11:42 p.m. UTC | #3
Hi Sakari,

On Wed, Apr 22, 2020 at 12:49:58AM +0300, Sakari Ailus wrote:
> On Sat, Apr 18, 2020 at 12:32:15PM +0200, Jacopo Mondi wrote:
> > From: Hans Verkuil <hans.verkuil@cisco.com>
> > 
> > While normal video/radio/vbi/swradio nodes have a proper QUERYCAP ioctl
> > that apps can call to determine that it is indeed a V4L2 device, there
> > is currently no equivalent for v4l-subdev nodes. Adding this ioctl will
> > solve that, and it will allow utilities like v4l2-compliance to be used
> > with these devices as well.
> > 
> > SUBDEV_QUERYCAP currently returns the version and subdev_caps of the
> > subdevice. Define as the initial set of subdev_caps the read-only or
> > read/write flags, to signal to userspace which set of IOCTLs are
> > available on the subdevice.
> > 
> > Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> > Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> > ---
> >  drivers/media/v4l2-core/v4l2-subdev.c | 12 ++++++++++++
> >  include/uapi/linux/v4l2-subdev.h      | 15 +++++++++++++++
> >  2 files changed, 27 insertions(+)
> > 
> > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> > index 1dc263c2ca0a..ca0aa54429c5 100644
> > --- a/drivers/media/v4l2-core/v4l2-subdev.c
> > +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> > @@ -15,6 +15,7 @@
> >  #include <linux/types.h>
> >  #include <linux/videodev2.h>
> >  #include <linux/export.h>
> > +#include <linux/version.h>
> >  
> >  #include <media/v4l2-ctrls.h>
> >  #include <media/v4l2-device.h>
> > @@ -336,6 +337,17 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
> >  	int rval;
> >  
> >  	switch (cmd) {
> > +	case VIDIOC_SUBDEV_QUERYCAP: {
> > +		struct v4l2_subdev_capability *cap = arg;
> > +
> > +		memset(cap, 0, sizeof(*cap));
> > +		cap->version = LINUX_VERSION_CODE;
> > +		cap->subdev_caps |= ro_subdev ? V4L2_SUBDEV_CAP_RO_SUBDEV
> > +					      : V4L2_SUBDEV_CAP_RW_SUBDEV;
> > +
> > +		return 0;
> > +	}
> > +
> >  	case VIDIOC_QUERYCTRL:
> >  		/*
> >  		 * TODO: this really should be folded into v4l2_queryctrl (this
> > diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
> > index 03970ce30741..0886f88be193 100644
> > --- a/include/uapi/linux/v4l2-subdev.h
> > +++ b/include/uapi/linux/v4l2-subdev.h
> > @@ -155,9 +155,24 @@ struct v4l2_subdev_selection {
> >  	__u32 reserved[8];
> >  };
> >  
> > +/**
> > + * struct v4l2_subdev_capability - subdev capabilities
> > + * @device_caps: the subdev capabilities, see V4L2_SUBDEV_CAP_*.
> > + */
> > +struct v4l2_subdev_capability {
> > +	__u32 version;
> > +	__u32 subdev_caps;
> 
> No reserved fields? Is the intent to extend this later on based on the size
> of the IOCTL argument?

That would be my preferred option.

> > +};
> > +
> > +/* The v4l2 sub-device video device node is registered in read-only mode. */
> > +#define V4L2_SUBDEV_CAP_RO_SUBDEV		(1 << 0)
> 
> 1U << 0

BIT(0)

> 
> > +/* The v4l2 sub-device video device node is registered in read/write mode. */
> > +#define V4L2_SUBDEV_CAP_RW_SUBDEV		(1 << 1)
> 
> 1U << 1

BIT(1)

> > +
> >  /* Backwards compatibility define --- to be removed */
> >  #define v4l2_subdev_edid v4l2_edid
> >  
> > +#define VIDIOC_SUBDEV_QUERYCAP			_IOR('V',  0, struct v4l2_subdev_capability)
> >  #define VIDIOC_SUBDEV_G_FMT			_IOWR('V',  4, struct v4l2_subdev_format)
> >  #define VIDIOC_SUBDEV_S_FMT			_IOWR('V',  5, struct v4l2_subdev_format)
> >  #define VIDIOC_SUBDEV_G_FRAME_INTERVAL		_IOWR('V', 21, struct v4l2_subdev_frame_interval)
Jacopo Mondi April 22, 2020, 6:57 a.m. UTC | #4
Hi Sakari,

On Wed, Apr 22, 2020 at 02:42:32AM +0300, Laurent Pinchart wrote:
> Hi Sakari,
>
> On Wed, Apr 22, 2020 at 12:49:58AM +0300, Sakari Ailus wrote:
> > On Sat, Apr 18, 2020 at 12:32:15PM +0200, Jacopo Mondi wrote:
> > > From: Hans Verkuil <hans.verkuil@cisco.com>
> > >
> > > While normal video/radio/vbi/swradio nodes have a proper QUERYCAP ioctl
> > > that apps can call to determine that it is indeed a V4L2 device, there
> > > is currently no equivalent for v4l-subdev nodes. Adding this ioctl will
> > > solve that, and it will allow utilities like v4l2-compliance to be used
> > > with these devices as well.
> > >
> > > SUBDEV_QUERYCAP currently returns the version and subdev_caps of the
> > > subdevice. Define as the initial set of subdev_caps the read-only or
> > > read/write flags, to signal to userspace which set of IOCTLs are
> > > available on the subdevice.
> > >
> > > Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
> > > Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> > > ---
> > >  drivers/media/v4l2-core/v4l2-subdev.c | 12 ++++++++++++
> > >  include/uapi/linux/v4l2-subdev.h      | 15 +++++++++++++++
> > >  2 files changed, 27 insertions(+)
> > >
> > > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> > > index 1dc263c2ca0a..ca0aa54429c5 100644
> > > --- a/drivers/media/v4l2-core/v4l2-subdev.c
> > > +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> > > @@ -15,6 +15,7 @@
> > >  #include <linux/types.h>
> > >  #include <linux/videodev2.h>
> > >  #include <linux/export.h>
> > > +#include <linux/version.h>
> > >
> > >  #include <media/v4l2-ctrls.h>
> > >  #include <media/v4l2-device.h>
> > > @@ -336,6 +337,17 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
> > >  	int rval;
> > >
> > >  	switch (cmd) {
> > > +	case VIDIOC_SUBDEV_QUERYCAP: {
> > > +		struct v4l2_subdev_capability *cap = arg;
> > > +
> > > +		memset(cap, 0, sizeof(*cap));
> > > +		cap->version = LINUX_VERSION_CODE;
> > > +		cap->subdev_caps |= ro_subdev ? V4L2_SUBDEV_CAP_RO_SUBDEV
> > > +					      : V4L2_SUBDEV_CAP_RW_SUBDEV;
> > > +
> > > +		return 0;
> > > +	}
> > > +
> > >  	case VIDIOC_QUERYCTRL:
> > >  		/*
> > >  		 * TODO: this really should be folded into v4l2_queryctrl (this
> > > diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
> > > index 03970ce30741..0886f88be193 100644
> > > --- a/include/uapi/linux/v4l2-subdev.h
> > > +++ b/include/uapi/linux/v4l2-subdev.h
> > > @@ -155,9 +155,24 @@ struct v4l2_subdev_selection {
> > >  	__u32 reserved[8];
> > >  };
> > >
> > > +/**
> > > + * struct v4l2_subdev_capability - subdev capabilities
> > > + * @device_caps: the subdev capabilities, see V4L2_SUBDEV_CAP_*.
> > > + */
> > > +struct v4l2_subdev_capability {
> > > +	__u32 version;
> > > +	__u32 subdev_caps;
> >
> > No reserved fields? Is the intent to extend this later on based on the size
> > of the IOCTL argument?
>
> That would be my preferred option.
>

That would be my preferred opinion as well, we would have versioning
and would not be tied to the available reserved fields.

Patch

diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 1dc263c2ca0a..ca0aa54429c5 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -15,6 +15,7 @@ 
 #include <linux/types.h>
 #include <linux/videodev2.h>
 #include <linux/export.h>
+#include <linux/version.h>
 
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
@@ -336,6 +337,17 @@  static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
 	int rval;
 
 	switch (cmd) {
+	case VIDIOC_SUBDEV_QUERYCAP: {
+		struct v4l2_subdev_capability *cap = arg;
+
+		memset(cap, 0, sizeof(*cap));
+		cap->version = LINUX_VERSION_CODE;
+		cap->subdev_caps |= ro_subdev ? V4L2_SUBDEV_CAP_RO_SUBDEV
+					      : V4L2_SUBDEV_CAP_RW_SUBDEV;
+
+		return 0;
+	}
+
 	case VIDIOC_QUERYCTRL:
 		/*
 		 * TODO: this really should be folded into v4l2_queryctrl (this
diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
index 03970ce30741..0886f88be193 100644
--- a/include/uapi/linux/v4l2-subdev.h
+++ b/include/uapi/linux/v4l2-subdev.h
@@ -155,9 +155,24 @@  struct v4l2_subdev_selection {
 	__u32 reserved[8];
 };
 
+/**
+ * struct v4l2_subdev_capability - subdev capabilities
+ * @device_caps: the subdev capabilities, see V4L2_SUBDEV_CAP_*.
+ */
+struct v4l2_subdev_capability {
+	__u32 version;
+	__u32 subdev_caps;
+};
+
+/* The v4l2 sub-device video device node is registered in read-only mode. */
+#define V4L2_SUBDEV_CAP_RO_SUBDEV		(1 << 0)
+/* The v4l2 sub-device video device node is registered in read/write mode. */
+#define V4L2_SUBDEV_CAP_RW_SUBDEV		(1 << 1)
+
 /* Backwards compatibility define --- to be removed */
 #define v4l2_subdev_edid v4l2_edid
 
+#define VIDIOC_SUBDEV_QUERYCAP			_IOR('V',  0, struct v4l2_subdev_capability)
 #define VIDIOC_SUBDEV_G_FMT			_IOWR('V',  4, struct v4l2_subdev_format)
 #define VIDIOC_SUBDEV_S_FMT			_IOWR('V',  5, struct v4l2_subdev_format)
 #define VIDIOC_SUBDEV_G_FRAME_INTERVAL		_IOWR('V', 21, struct v4l2_subdev_frame_interval)