[RFC v3] [RFC] v4l2: Support for multiple selections

[Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>]

Extend v4l2 selection API to support multiple selection areas, this way
sensors that support multiple readout areas can work with multiple areas
of insterest.

The struct v4l2_selection and v4l2_subdev_selection has been extented
with a new field rectangles. If it is value is different than zero the
pr array is used instead of the r field.

A new structure v4l2_ext_rect has been defined, containing 4 reserved
fields for future improvements, as suggested by Hans.

Two helper functiona are also added, to help the drivers that support
a single selection.

This Patch ONLY adds the modification to the core. Once it is agreed, a
new version including changes on the drivers that handle the selection
api will come.

This patch includes all the comments by Hans Verkuil.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
v3:
-Changes on compat-ioctl32
-Remove checks on v4l2_selection_set_rect

 drivers/media/v4l2-core/v4l2-common.c         | 36 +++++++++++++++
 drivers/media/v4l2-core/v4l2-compat-ioctl32.c | 63 +++++++++++++++++++++++++++
 drivers/media/v4l2-core/v4l2-ioctl.c          | 37 +++++++++++++---
 include/media/v4l2-common.h                   |  6 +++
 include/uapi/linux/v4l2-subdev.h              | 10 ++++-
 include/uapi/linux/videodev2.h                | 21 +++++++--
 6 files changed, 162 insertions(+), 11 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
index a95e5e2..f60a2ce 100644
--- a/drivers/media/v4l2-core/v4l2-common.c
+++ b/drivers/media/v4l2-core/v4l2-common.c
@@ -886,3 +886,39 @@ void v4l2_get_timestamp(struct timeval *tv)
 	tv->tv_usec = ts.tv_nsec / NSEC_PER_USEC;
 }
 EXPORT_SYMBOL_GPL(v4l2_get_timestamp);
+
+int v4l2_selection_get_rect(const struct v4l2_selection *s,
+					struct v4l2_ext_rect *r)
+{
+	if (s->rectangles > 1)
+		return -EINVAL;
+	if (s->rectangles == 1) {
+		*r = s->pr[0];
+		return 0;
+	}
+	if (s->r.width < 0 || s->r.height < 0)
+		return -EINVAL;
+	r->left = s->r.left;
+	r->top = s->r.top;
+	r->width = s->r.width;
+	r->height = s->r.height;
+	memset(r->reserved, 0, sizeof(r->reserved));
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_selection_get_rect);
+
+void v4l2_selection_set_rect(struct v4l2_selection *s,
+				const struct v4l2_ext_rect *r)
+{
+	if (s->rectangles == 0) {
+		s->r.left = r->left;
+		s->r.top = r->top;
+		s->r.width = r->width;
+		s->r.height = r->height;
+		return;
+	}
+	s->pr[0] = *r;
+	s->rectangles = 1;
+	return;
+}
+EXPORT_SYMBOL_GPL(v4l2_selection_set_rect);
diff --git a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
index 8f7a6a4..36ed3c3 100644
--- a/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
+++ b/drivers/media/v4l2-core/v4l2-compat-ioctl32.c
@@ -777,6 +777,54 @@ static int put_v4l2_subdev_edid32(struct v4l2_subdev_edid *kp, struct v4l2_subde
 	return 0;
 }
 
+struct v4l2_selection32 {
+	__u32			type;
+	__u32			target;
+	__u32                   flags;
+	union {
+		struct v4l2_rect        r;
+		compat_uptr_t           *pr;
+	};
+	__u32                   rectangles;
+	__u32                   reserved[8];
+} __packed;
+
+static int get_v4l2_selection32(struct v4l2_selection *kp,
+				struct v4l2_selection32 __user *up)
+{
+	if (!access_ok(VERIFY_READ, up, sizeof(struct v4l2_selection32))
+				|| (copy_from_user(kp, up, sizeof(*kp))))
+		return -EFAULT;
+
+	if (kp->rectangles) {
+		compat_uptr_t usr_ptr;
+		if (get_user(usr_ptr, &up->pr))
+			return -EFAULT;
+		kp->pr = compat_ptr(usr_ptr);
+	}
+
+	return 0;
+
+}
+
+static int put_v4l2_selection32(struct v4l2_selection *kp,
+				struct v4l2_selection32 __user *up)
+{
+	compat_uptr_t usr_ptr = 0;
+
+	if ((kp->rectangles) &&	get_user(usr_ptr, &up->pr))
+		return -EFAULT;
+
+	if (!access_ok(VERIFY_WRITE, up, sizeof(struct v4l2_selection32))
+				|| (copy_to_user(kp, up, sizeof(*kp))))
+		return -EFAULT;
+
+	if (kp->rectangles)
+		put_user(usr_ptr, &up->pr);
+
+	return 0;
+
+}
 
 #define VIDIOC_G_FMT32		_IOWR('V',  4, struct v4l2_format32)
 #define VIDIOC_S_FMT32		_IOWR('V',  5, struct v4l2_format32)
@@ -796,6 +844,8 @@ static int put_v4l2_subdev_edid32(struct v4l2_subdev_edid *kp, struct v4l2_subde
 #define	VIDIOC_DQEVENT32	_IOR ('V', 89, struct v4l2_event32)
 #define VIDIOC_CREATE_BUFS32	_IOWR('V', 92, struct v4l2_create_buffers32)
 #define VIDIOC_PREPARE_BUF32	_IOWR('V', 93, struct v4l2_buffer32)
+#define VIDIOC_G_SELECTION32	_IOWR('V', 94, struct v4l2_selection32)
+#define VIDIOC_S_SELECTION32	_IOWR('V', 95, struct v4l2_selection32)
 
 #define VIDIOC_OVERLAY32	_IOW ('V', 14, s32)
 #define VIDIOC_STREAMON32	_IOW ('V', 18, s32)
@@ -817,6 +867,7 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 		struct v4l2_event v2ev;
 		struct v4l2_create_buffers v2crt;
 		struct v4l2_subdev_edid v2edid;
+		struct v4l2_selection v2sel;
 		unsigned long vx;
 		int vi;
 	} karg;
@@ -851,6 +902,8 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 	case VIDIOC_PREPARE_BUF32: cmd = VIDIOC_PREPARE_BUF; break;
 	case VIDIOC_SUBDEV_G_EDID32: cmd = VIDIOC_SUBDEV_G_EDID; break;
 	case VIDIOC_SUBDEV_S_EDID32: cmd = VIDIOC_SUBDEV_S_EDID; break;
+	case VIDIOC_G_SELECTION32: cmd = VIDIOC_G_SELECTION; break;
+	case VIDIOC_S_SELECTION32: cmd = VIDIOC_S_SELECTION; break;
 	}
 
 	switch (cmd) {
@@ -922,6 +975,11 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 	case VIDIOC_DQEVENT:
 		compatible_arg = 0;
 		break;
+	case VIDIOC_G_SELECTION:
+	case VIDIOC_S_SELECTION:
+		err = get_v4l2_selection32(&karg.v2sel, up);
+		compatible_arg = 0;
+		break;
 	}
 	if (err)
 		return err;
@@ -994,6 +1052,11 @@ static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long ar
 	case VIDIOC_ENUMINPUT:
 		err = put_v4l2_input32(&karg.v2i, up);
 		break;
+
+	case VIDIOC_G_SELECTION:
+	case VIDIOC_S_SELECTION:
+		err = put_v4l2_selection32(&karg.v2sel, up);
+		break;
 	}
 	return err;
 }
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 68e6b5e..aa1c2a4 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -572,11 +572,22 @@ static void v4l_print_crop(const void *arg, bool write_only)
 static void v4l_print_selection(const void *arg, bool write_only)
 {
 	const struct v4l2_selection *p = arg;
+	int i;
 
-	pr_cont("type=%s, target=%d, flags=0x%x, wxh=%dx%d, x,y=%d,%d\n",
-		prt_names(p->type, v4l2_type_names),
-		p->target, p->flags,
-		p->r.width, p->r.height, p->r.left, p->r.top);
+	if (p->rectangles == 0)
+		pr_cont("type=%s, target=%d, flags=0x%x, wxh=%dx%d, x,y=%d,%d\n",
+			prt_names(p->type, v4l2_type_names),
+			p->target, p->flags,
+			p->r.width, p->r.height, p->r.left, p->r.top);
+	else{
+		pr_cont("type=%s, target=%d, flags=0x%x rectangles=%d\n",
+			prt_names(p->type, v4l2_type_names),
+			p->target, p->flags, p->rectangles);
+		for (i = 0; i < p->rectangles; i++)
+			pr_cont("rectangle %d: wxh=%dx%d, x,y=%d,%d\n",
+				i, p->r.width, p->r.height,
+				p->r.left, p->r.top);
+	}
 }
 
 static void v4l_print_jpegcompression(const void *arg, bool write_only)
@@ -1692,7 +1703,9 @@ static int v4l_cropcap(const struct v4l2_ioctl_ops *ops,
 				struct file *file, void *fh, void *arg)
 {
 	struct v4l2_cropcap *p = arg;
-	struct v4l2_selection s = { .type = p->type };
+	struct v4l2_selection s = {
+		.type = p->type,
+	};
 	int ret;
 
 	if (ops->vidioc_cropcap)
@@ -2253,6 +2266,20 @@ static int check_array_args(unsigned int cmd, void *parg, size_t *array_size,
 		}
 		break;
 	}
+
+	case VIDIOC_G_SELECTION:
+	case VIDIOC_S_SELECTION: {
+		struct v4l2_selection *s = parg;
+
+		if (s->rectangles) {
+			*user_ptr = (void __user *)s->pr;
+			*kernel_ptr = (void *)&s->pr;
+			*array_size = sizeof(struct v4l2_ext_rect)
+				* s->rectangles;
+			ret = 1;
+		}
+		break;
+	}
 	}
 
 	return ret;
diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h
index 015ff82..417ab82 100644
--- a/include/media/v4l2-common.h
+++ b/include/media/v4l2-common.h
@@ -216,4 +216,10 @@ struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait);
 
 void v4l2_get_timestamp(struct timeval *tv);
 
+int v4l2_selection_get_rect(const struct v4l2_selection *s,
+					struct v4l2_ext_rect *r);
+
+void v4l2_selection_set_rect(struct v4l2_selection *s,
+					const struct v4l2_ext_rect *r);
+
 #endif /* V4L2_COMMON_H_ */
diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
index a33c4da..c02a886 100644
--- a/include/uapi/linux/v4l2-subdev.h
+++ b/include/uapi/linux/v4l2-subdev.h
@@ -133,6 +133,8 @@ struct v4l2_subdev_frame_interval_enum {
  *	    defined in v4l2-common.h; V4L2_SEL_TGT_* .
  * @flags: constraint flags, defined in v4l2-common.h; V4L2_SEL_FLAG_*.
  * @r: coordinates of the selection window
+ * @pr:		array of rectangles containing the selection windows
+ * @rectangles:	Number of rectangles in pr structure. If zero, r is used instead
  * @reserved: for future use, set to zero for now
  *
  * Hardware may use multiple helper windows to process a video stream.
@@ -144,8 +146,12 @@ struct v4l2_subdev_selection {
 	__u32 pad;
 	__u32 target;
 	__u32 flags;
-	struct v4l2_rect r;
-	__u32 reserved[8];
+	union {
+		struct v4l2_rect r;
+		struct v4l2_ext_rect *pr;
+	};
+	__u32 rectangles;
+	__u32 reserved[7];
 };
 
 struct v4l2_subdev_edid {
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 95ef455..a4a7902 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -211,6 +211,14 @@ struct v4l2_rect {
 	__s32   height;
 };
 
+struct v4l2_ext_rect {
+	__s32   left;
+	__s32   top;
+	__u32   width;
+	__u32   height;
+	__u32   reserved[4];
+};
+
 struct v4l2_fract {
 	__u32   numerator;
 	__u32   denominator;
@@ -804,6 +812,8 @@ struct v4l2_crop {
  *		defined in v4l2-common.h; V4L2_SEL_TGT_* .
  * @flags:	constraints flags, defined in v4l2-common.h; V4L2_SEL_FLAG_*.
  * @r:		coordinates of selection window
+ * @pr:		array of rectangles containing the selection windows
+ * @rectangles:	Number of rectangles in pr structure. If zero, r is used instead
  * @reserved:	for future use, rounds structure size to 64 bytes, set to zero
  *
  * Hardware may use multiple helper windows to process a video stream.
@@ -814,10 +824,13 @@ struct v4l2_selection {
 	__u32			type;
 	__u32			target;
 	__u32                   flags;
-	struct v4l2_rect        r;
-	__u32                   reserved[9];
-};
-
+	union {
+		struct v4l2_rect        r;
+		struct v4l2_ext_rect    *pr;
+	};
+	__u32                   rectangles;
+	__u32                   reserved[8];
+} __packed;
 
 /*
  *      A N A L O G   V I D E O   S T A N D A R D
-- 
1.8.4.rc3