This patch implements UVC 1.5 Region of Interest (ROI) control.

Note that, UVC 1.5 defines CT_DIGITAL_WINDOW_CONTROL controls
and mentions that ROI rectangle coordinates "must be within
the current Digital Window as specified by the CT_WINDOW control."
(4.2.2.1.20 Digital Region of Interest (ROI) Control).

It's is not entirely clear if we need to implement WINDOW_CONTROL.
ROI is naturally limited by GET_MIN and GET_MAX rectangles.

Another thing to note is that ROI support is implemented as
V4L2 selection target: selection rectangle represents ROI
rectangle and selection flags represent ROI auto-controls.
User-space is required to set valid values for both rectangle
and auto-controls every time SET_CUR is issued.

Usage example:

       struct v4l2_selection roi = {0, };

       roi.target     = V4L2_SEL_TGT_ROI;
       roi.r.left     = 0;
       roi.r.top      = 0;
       roi.r.width    = 42;
       roi.r.height   = 42;
       roi.flags      = V4L2_SEL_FLAG_ROI_AUTO_EXPOSURE;

       ioctl(fd, VIDIOC_S_SELECTION, &roi);

Signed-off-by: Sergey Senozhatsky <senozhat...@chromium.org>
---
 drivers/media/usb/uvc/uvc_v4l2.c | 147 ++++++++++++++++++++++++++++++-
 include/uapi/linux/usb/video.h   |   1 +
 2 files changed, 145 insertions(+), 3 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 252136cc885c..d0fe6c33fab6 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -1139,14 +1139,66 @@ static int uvc_ioctl_querymenu(struct file *file, void 
*fh,
        return uvc_query_v4l2_menu(chain, qm);
 }
 
-static int uvc_ioctl_g_selection(struct file *file, void *fh,
-                                struct v4l2_selection *sel)
+/* UVC 1.5 ROI rectangle is half the size of v4l2_rect */
+struct uvc_roi_rect {
+       __u16                   top;
+       __u16                   left;
+       __u16                   bottom;
+       __u16                   right;
+       __u16                   auto_controls;
+} __packed;
+
+static int uvc_ioctl_g_roi_target(struct file *file, void *fh,
+                                 struct v4l2_selection *sel)
 {
        struct uvc_fh *handle = fh;
        struct uvc_streaming *stream = handle->stream;
+       struct uvc_roi_rect *roi;
+       u8 query;
+       int ret;
 
-       if (sel->type != stream->type)
+       switch (sel->target) {
+       case V4L2_SEL_TGT_ROI:
+               query = UVC_GET_CUR;
+               break;
+       case V4L2_SEL_TGT_ROI_DEFAULT:
+               query = UVC_GET_DEF;
+               break;
+       case V4L2_SEL_TGT_ROI_BOUNDS_MIN:
+               query = UVC_GET_MAX;
+               break;
+       case V4L2_SEL_TGT_ROI_BOUNDS_MAX:
+               query = UVC_GET_MAX;
+               break;
+       default:
                return -EINVAL;
+       }
+
+       roi = kzalloc(sizeof(struct uvc_roi_rect), GFP_KERNEL);
+       if (!roi)
+               return -ENOMEM;
+
+       ret = uvc_query_ctrl(stream->dev, query, 1, stream->dev->intfnum,
+                            UVC_CT_REGION_OF_INTEREST_CONTROL, roi,
+                            sizeof(struct uvc_roi_rect));
+       if (!ret) {
+               /* ROI left, top, right, bottom are global coordinates. */
+               sel->r.left     = roi->left;
+               sel->r.top      = roi->top;
+               sel->r.width    = roi->right - roi->left + 1;
+               sel->r.height   = roi->bottom - roi->top + 1;
+               sel->flags      = roi->auto_controls;
+       }
+
+       kfree(roi);
+       return ret;
+}
+
+static int uvc_ioctl_g_sel_target(struct file *file, void *fh,
+                                 struct v4l2_selection *sel)
+{
+       struct uvc_fh *handle = fh;
+       struct uvc_streaming *stream = handle->stream;
 
        switch (sel->target) {
        case V4L2_SEL_TGT_CROP_DEFAULT:
@@ -1173,6 +1225,94 @@ static int uvc_ioctl_g_selection(struct file *file, void 
*fh,
        return 0;
 }
 
+static int uvc_ioctl_g_selection(struct file *file, void *fh,
+                                struct v4l2_selection *sel)
+{
+       struct uvc_fh *handle = fh;
+       struct uvc_streaming *stream = handle->stream;
+
+       if (sel->type != stream->type)
+               return -EINVAL;
+
+       switch (sel->target) {
+       case V4L2_SEL_TGT_CROP_DEFAULT:
+       case V4L2_SEL_TGT_CROP_BOUNDS:
+       case V4L2_SEL_TGT_COMPOSE_DEFAULT:
+       case V4L2_SEL_TGT_COMPOSE_BOUNDS:
+               return uvc_ioctl_g_sel_target(file, fh, sel);
+       case V4L2_SEL_TGT_ROI:
+       case V4L2_SEL_TGT_ROI_DEFAULT:
+       case V4L2_SEL_TGT_ROI_BOUNDS_MIN:
+       case V4L2_SEL_TGT_ROI_BOUNDS_MAX:
+               return uvc_ioctl_g_roi_target(file, fh, sel);
+       }
+
+       return -EINVAL;
+}
+
+static bool validate_roi_bounds(struct uvc_streaming *stream,
+                               struct v4l2_selection *sel)
+{
+       if (sel->r.left > USHRT_MAX ||
+           sel->r.top > USHRT_MAX ||
+           (sel->r.width + sel->r.left) > USHRT_MAX ||
+           (sel->r.height + sel->r.top) > USHRT_MAX ||
+           !sel->r.width || !sel->r.height)
+               return false;
+
+       if (sel->flags > V4L2_SEL_FLAG_ROI_AUTO_HIGHER_QUALITY)
+               return false;
+
+       return true;
+}
+
+static int uvc_ioctl_s_roi(struct file *file, void *fh,
+                          struct v4l2_selection *sel)
+{
+       struct uvc_fh *handle = fh;
+       struct uvc_streaming *stream = handle->stream;
+       struct uvc_roi_rect *roi;
+       int ret;
+
+       if (!validate_roi_bounds(stream, sel))
+               return -E2BIG;
+
+       roi = kzalloc(sizeof(struct uvc_roi_rect), GFP_KERNEL);
+       if (!roi)
+               return -ENOMEM;
+
+       /* ROI left, top, right, bottom are global coordinates. */
+       roi->left               = sel->r.left;
+       roi->top                = sel->r.top;
+       roi->right              = sel->r.width + sel->r.left - 1;
+       roi->bottom             = sel->r.height + sel->r.top - 1;
+       roi->auto_controls      = sel->flags;
+
+       ret = uvc_query_ctrl(stream->dev, UVC_SET_CUR, 1, stream->dev->intfnum,
+                            UVC_CT_REGION_OF_INTEREST_CONTROL, roi,
+                            sizeof(struct uvc_roi_rect));
+
+       kfree(roi);
+       return ret;
+}
+
+static int uvc_ioctl_s_selection(struct file *file, void *fh,
+                                struct v4l2_selection *sel)
+{
+       struct uvc_fh *handle = fh;
+       struct uvc_streaming *stream = handle->stream;
+
+       if (sel->type != stream->type)
+               return -EINVAL;
+
+       switch (sel->target) {
+       case V4L2_SEL_TGT_ROI:
+               return uvc_ioctl_s_roi(file, fh, sel);
+       }
+
+       return -EINVAL;
+}
+
 static int uvc_ioctl_g_parm(struct file *file, void *fh,
                            struct v4l2_streamparm *parm)
 {
@@ -1533,6 +1673,7 @@ const struct v4l2_ioctl_ops uvc_ioctl_ops = {
        .vidioc_try_ext_ctrls = uvc_ioctl_try_ext_ctrls,
        .vidioc_querymenu = uvc_ioctl_querymenu,
        .vidioc_g_selection = uvc_ioctl_g_selection,
+       .vidioc_s_selection = uvc_ioctl_s_selection,
        .vidioc_g_parm = uvc_ioctl_g_parm,
        .vidioc_s_parm = uvc_ioctl_s_parm,
        .vidioc_enum_framesizes = uvc_ioctl_enum_framesizes,
diff --git a/include/uapi/linux/usb/video.h b/include/uapi/linux/usb/video.h
index d854cb19c42c..c87624962896 100644
--- a/include/uapi/linux/usb/video.h
+++ b/include/uapi/linux/usb/video.h
@@ -104,6 +104,7 @@
 #define UVC_CT_ROLL_ABSOLUTE_CONTROL                   0x0f
 #define UVC_CT_ROLL_RELATIVE_CONTROL                   0x10
 #define UVC_CT_PRIVACY_CONTROL                         0x11
+#define UVC_CT_REGION_OF_INTEREST_CONTROL              0x14
 
 /* A.9.5. Processing Unit Control Selectors */
 #define UVC_PU_CONTROL_UNDEFINED                       0x00
-- 
2.31.0.rc2.261.g7f71774620-goog

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