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[media] uvcvideo: Add UVCIOC_CTRL_QUERY ioctl
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This ioctl extends UVCIOC_CTRL_GET/SET by not only allowing to get/set
XU controls but to also send arbitrary UVC commands to XU controls,
namely GET_CUR, SET_CUR, GET_MIN, GET_MAX, GET_RES, GET_LEN, GET_INFO
and GET_DEF. This is required for applications to work with XU controls,
so that they can properly query the size and allocate the necessary
buffers.

Signed-off-by: Martin Rubli <martin_rubli@logitech.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
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Martin Rubli authored and Mauro Carvalho Chehab committed May 20, 2011
1 parent 837d50b commit fe78d18
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Showing 3 changed files with 88 additions and 36 deletions.
92 changes: 61 additions & 31 deletions drivers/media/video/uvc/uvc_ctrl.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1344,41 +1344,42 @@ static int uvc_ctrl_init_xu_ctrl(struct uvc_device *dev,
}

int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
struct uvc_xu_control *xctrl, int set)
struct uvc_xu_control_query *xqry)
{
struct uvc_entity *entity;
struct uvc_control *ctrl = NULL;
struct uvc_control *ctrl;
unsigned int i, found = 0;
int restore = 0;
__u8 *data;
__u32 reqflags;
__u16 size;
__u8 *data = NULL;
int ret;

/* Find the extension unit. */
list_for_each_entry(entity, &chain->entities, chain) {
if (UVC_ENTITY_TYPE(entity) == UVC_VC_EXTENSION_UNIT &&
entity->id == xctrl->unit)
entity->id == xqry->unit)
break;
}

if (entity->id != xctrl->unit) {
if (entity->id != xqry->unit) {
uvc_trace(UVC_TRACE_CONTROL, "Extension unit %u not found.\n",
xctrl->unit);
return -EINVAL;
xqry->unit);
return -ENOENT;
}

/* Find the control and perform delayed initialization if needed. */
for (i = 0; i < entity->ncontrols; ++i) {
ctrl = &entity->controls[i];
if (ctrl->index == xctrl->selector - 1) {
if (ctrl->index == xqry->selector - 1) {
found = 1;
break;
}
}

if (!found) {
uvc_trace(UVC_TRACE_CONTROL, "Control %pUl/%u not found.\n",
entity->extension.guidExtensionCode, xctrl->selector);
return -EINVAL;
entity->extension.guidExtensionCode, xqry->selector);
return -ENOENT;
}

if (mutex_lock_interruptible(&chain->ctrl_mutex))
Expand All @@ -1390,43 +1391,72 @@ int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
goto done;
}

/* Validate control data size. */
if (ctrl->info.size != xctrl->size) {
/* Validate the required buffer size and flags for the request */
reqflags = 0;
size = ctrl->info.size;

switch (xqry->query) {
case UVC_GET_CUR:
reqflags = UVC_CONTROL_GET_CUR;
break;
case UVC_GET_MIN:
reqflags = UVC_CONTROL_GET_MIN;
break;
case UVC_GET_MAX:
reqflags = UVC_CONTROL_GET_MAX;
break;
case UVC_GET_DEF:
reqflags = UVC_CONTROL_GET_DEF;
break;
case UVC_GET_RES:
reqflags = UVC_CONTROL_GET_RES;
break;
case UVC_SET_CUR:
reqflags = UVC_CONTROL_SET_CUR;
break;
case UVC_GET_LEN:
size = 2;
break;
case UVC_GET_INFO:
size = 1;
break;
default:
ret = -EINVAL;
goto done;
}

if ((set && !(ctrl->info.flags & UVC_CONTROL_SET_CUR)) ||
(!set && !(ctrl->info.flags & UVC_CONTROL_GET_CUR))) {
ret = -EINVAL;
if (size != xqry->size) {
ret = -ENOBUFS;
goto done;
}

memcpy(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_BACKUP),
uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
ctrl->info.size);
data = uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT);
restore = set;
if (reqflags && !(ctrl->info.flags & reqflags)) {
ret = -EBADRQC;
goto done;
}

if (set && copy_from_user(data, xctrl->data, xctrl->size)) {
data = kmalloc(size, GFP_KERNEL);
if (data == NULL) {
ret = -ENOMEM;
goto done;
}

if (xqry->query == UVC_SET_CUR &&
copy_from_user(data, xqry->data, size)) {
ret = -EFAULT;
goto done;
}

ret = uvc_query_ctrl(chain->dev, set ? UVC_SET_CUR : UVC_GET_CUR,
xctrl->unit, chain->dev->intfnum, xctrl->selector,
data, xctrl->size);
ret = uvc_query_ctrl(chain->dev, xqry->query, xqry->unit,
chain->dev->intfnum, xqry->selector, data, size);
if (ret < 0)
goto done;

if (!set && copy_to_user(xctrl->data, data, xctrl->size))
if (xqry->query != UVC_SET_CUR &&
copy_to_user(xqry->data, data, size))
ret = -EFAULT;
done:
if (ret && restore)
memcpy(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
uvc_ctrl_data(ctrl, UVC_CTRL_DATA_BACKUP),
xctrl->size);

kfree(data);
mutex_unlock(&chain->ctrl_mutex);
return ret;
}
Expand Down
19 changes: 16 additions & 3 deletions drivers/media/video/uvc/uvc_v4l2.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1029,10 +1029,23 @@ static long uvc_v4l2_do_ioctl(struct file *file, unsigned int cmd, void *arg)
cmd == UVCIOC_CTRL_MAP_OLD);

case UVCIOC_CTRL_GET:
return uvc_xu_ctrl_query(chain, arg, 0);

case UVCIOC_CTRL_SET:
return uvc_xu_ctrl_query(chain, arg, 1);
{
struct uvc_xu_control *xctrl = arg;
struct uvc_xu_control_query xqry = {
.unit = xctrl->unit,
.selector = xctrl->selector,
.query = cmd == UVCIOC_CTRL_GET
? UVC_GET_CUR : UVC_SET_CUR,
.size = xctrl->size,
.data = xctrl->data,
};

return uvc_xu_ctrl_query(chain, &xqry);
}

case UVCIOC_CTRL_QUERY:
return uvc_xu_ctrl_query(chain, arg);

default:
uvc_trace(UVC_TRACE_IOCTL, "Unknown ioctl 0x%08x\n", cmd);
Expand Down
13 changes: 11 additions & 2 deletions drivers/media/video/uvc/uvcvideo.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,7 @@ struct uvc_xu_control_mapping {

__u8 size;
__u8 offset;
enum v4l2_ctrl_type v4l2_type;
__u32 v4l2_type;
__u32 data_type;

struct uvc_menu_info __user *menu_info;
Expand All @@ -73,11 +73,20 @@ struct uvc_xu_control {
__u8 __user *data;
};

struct uvc_xu_control_query {
__u8 unit;
__u8 selector;
__u8 query;
__u16 size;
__u8 __user *data;
};

#define UVCIOC_CTRL_ADD _IOW('U', 1, struct uvc_xu_control_info)
#define UVCIOC_CTRL_MAP_OLD _IOWR('U', 2, struct uvc_xu_control_mapping_old)
#define UVCIOC_CTRL_MAP _IOWR('U', 2, struct uvc_xu_control_mapping)
#define UVCIOC_CTRL_GET _IOWR('U', 3, struct uvc_xu_control)
#define UVCIOC_CTRL_SET _IOW('U', 4, struct uvc_xu_control)
#define UVCIOC_CTRL_QUERY _IOWR('U', 5, struct uvc_xu_control_query)

#ifdef __KERNEL__

Expand Down Expand Up @@ -638,7 +647,7 @@ extern int uvc_ctrl_set(struct uvc_video_chain *chain,
struct v4l2_ext_control *xctrl);

extern int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
struct uvc_xu_control *ctrl, int set);
struct uvc_xu_control_query *xqry);

/* Utility functions */
extern void uvc_simplify_fraction(uint32_t *numerator, uint32_t *denominator,
Expand Down

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