uvc_ctrl.c

linux camera下的uvc driver驱动源码

}

/* Extract the bit string specified by mapping->offset and mapping->size
 * from the little-endian data stored at 'data' and return the result as
 * a signed 32bit integer. Sign extension will be performed if the mapping
 * references a signed data type.
 */
static __s32 uvc_get_le_value(const __u8 *data,
	struct uvc_control_mapping *mapping)
{
	int bits = mapping->size;
	int offset = mapping->offset;
	__s32 value = 0;
	__u8 mask;

	data += offset / 8;
	offset &= 7;
	mask = ((1LL << bits) - 1) << offset;

	for (; bits > 0; data++) {
		__u8 byte = *data & mask;
		value |= offset > 0 ? (byte >> offset) : (byte << (-offset));
		bits -= 8 - (offset > 0 ? offset : 0);
		offset -= 8;
		mask = (1 << bits) - 1;
	}

	/* Sign-extend the value if needed */
	if (mapping->data_type == UVC_CTRL_DATA_TYPE_SIGNED)
		value |= -(value & (1 << (mapping->size - 1)));

	return value;
}

/* Set the bit string specified by mapping->offset and mapping->size
 * in the little-endian data stored at 'data' to the value 'value'.
 */
static void uvc_set_le_value(__s32 value, __u8 *data,
	struct uvc_control_mapping *mapping)
{
	int bits = mapping->size;
	int offset = mapping->offset;
	__u8 mask;

	data += offset / 8;
	offset &= 7;

	for (; bits > 0; data++) {
		mask = ((1LL << bits) - 1) << offset;
		*data = (*data & ~mask) | ((value << offset) & mask);
		value >>= offset ? offset : 8;
		bits -= 8 - offset;
		offset = 0;
	}
}

/* ------------------------------------------------------------------------
 * Terminal and unit management
 */

static const __u8 uvc_processing_guid[16] = UVC_GUID_UVC_PROCESSING;
static const __u8 uvc_camera_guid[16] = UVC_GUID_UVC_CAMERA;
static const __u8 uvc_media_transport_input_guid[16] = UVC_GUID_UVC_MEDIA_TRANSPORT_INPUT;

static int uvc_entity_match_guid(struct uvc_entity *entity, __u8 guid[16])
{
	switch (UVC_ENTITY_TYPE(entity)) {
	case ITT_CAMERA:
		return memcmp(uvc_camera_guid, guid, 16) == 0;

	case ITT_MEDIA_TRANSPORT_INPUT:
		return memcmp(uvc_media_transport_input_guid, guid, 16) == 0;

	case VC_PROCESSING_UNIT:
		return memcmp(uvc_processing_guid, guid, 16) == 0;

	case VC_EXTENSION_UNIT:
		return memcmp(entity->extension.guidExtensionCode, guid, 16) == 0;

	default:
		return 0;
	}
}

/* ------------------------------------------------------------------------
 * UVC Controls
 */

static void __uvc_find_control(struct uvc_entity *entity, __u32 v4l2_id,
	struct uvc_control_mapping **mapping, struct uvc_control **control,
	int next)
{
	struct uvc_control *ctrl;
	struct uvc_control_mapping *map;
	unsigned int i;

	if (entity == NULL)
		return;

	for (i = 0; i < entity->ncontrols; ++i) {
		ctrl = &entity->controls[i];
		if (ctrl->info == NULL)
			continue;

		list_for_each_entry(map, &ctrl->info->mappings, list) {
			if ((map->id == v4l2_id) && !next) {
				*control = ctrl;
				*mapping = map;
				return;
			}

			if ((*mapping == NULL || (*mapping)->id > map->id) &&
			    (map->id > v4l2_id) && next) {
				*control = ctrl;
				*mapping = map;
			}
		}
	}
}

struct uvc_control *uvc_find_control(struct uvc_video_device *video,
	__u32 v4l2_id, struct uvc_control_mapping **mapping)
{
	struct uvc_control *ctrl = NULL;
	struct uvc_entity *entity;
	int next = v4l2_id & V4L2_CTRL_FLAG_NEXT_CTRL;

	*mapping = NULL;

	/* Mask the query flags. */
	v4l2_id &= V4L2_CTRL_ID_MASK;

	/* Find the control. */
	__uvc_find_control(video->processing, v4l2_id, mapping, &ctrl, next);
	if (ctrl && !next)
		return ctrl;

	list_for_each_entry(entity, &video->iterms, chain) {
		__uvc_find_control(entity, v4l2_id, mapping, &ctrl, next);
		if (ctrl && !next)
			return ctrl;
	}

	list_for_each_entry(entity, &video->extensions, chain) {
		__uvc_find_control(entity, v4l2_id, mapping, &ctrl, next);
		if (ctrl && !next)
			return ctrl;
	}

	if (ctrl == NULL && !next)
		uvc_trace(UVC_TRACE_CONTROL, "Control 0x%08x not found.\n",
				v4l2_id);

	return ctrl;
}

int uvc_query_v4l2_ctrl(struct uvc_video_device *video, struct v4l2_queryctrl *v4l2_ctrl)
{
	struct uvc_control *ctrl;
	struct uvc_control_mapping *mapping;
	struct uvc_menu_info *menu;
	unsigned int i;
	__u8 data[8];
	int ret;

	ctrl = uvc_find_control(video, v4l2_ctrl->id, &mapping);
	if (ctrl == NULL)
		return -EINVAL;

	v4l2_ctrl->id = mapping->id;
	v4l2_ctrl->type = mapping->v4l2_type;
	strncpy(v4l2_ctrl->name, mapping->name, sizeof v4l2_ctrl->name);
	v4l2_ctrl->flags = 0;

	if (!(ctrl->info->flags & UVC_CONTROL_SET_CUR))
		v4l2_ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;

	if (ctrl->info->flags & UVC_CONTROL_GET_DEF) {
		if ((ret = uvc_query_ctrl(video->dev, GET_DEF, ctrl->entity->id,
					video->dev->intfnum, ctrl->info->selector,
					&data, ctrl->info->size)) < 0)
			return ret;
		v4l2_ctrl->default_value = uvc_get_le_value(data, mapping);
	}

	if (mapping->v4l2_type == V4L2_CTRL_TYPE_MENU) {
		v4l2_ctrl->minimum = 0;
		v4l2_ctrl->maximum = mapping->menu_count - 1;
		v4l2_ctrl->step = 1;

		menu = mapping->menu_info;
		for (i = 0; i < mapping->menu_count; ++i, ++menu) {
			if (menu->value == v4l2_ctrl->default_value) {
				v4l2_ctrl->default_value = i;
				break;
			}
		}

		return 0;
	}

	if (ctrl->info->flags & UVC_CONTROL_GET_MIN) {
		if ((ret = uvc_query_ctrl(video->dev, GET_MIN, ctrl->entity->id,
					video->dev->intfnum, ctrl->info->selector,
					&data, ctrl->info->size)) < 0)
			return ret;
		v4l2_ctrl->minimum = uvc_get_le_value(data, mapping);
	}
	if (ctrl->info->flags & UVC_CONTROL_GET_MAX) {
		if ((ret = uvc_query_ctrl(video->dev, GET_MAX, ctrl->entity->id,
					video->dev->intfnum, ctrl->info->selector,
					&data, ctrl->info->size)) < 0)
			return ret;
		v4l2_ctrl->maximum = uvc_get_le_value(data, mapping);
	}
	if (ctrl->info->flags & UVC_CONTROL_GET_RES) {
		if ((ret = uvc_query_ctrl(video->dev, GET_RES, ctrl->entity->id,
					video->dev->intfnum, ctrl->info->selector,
					&data, ctrl->info->size)) < 0)
			return ret;
		v4l2_ctrl->step = uvc_get_le_value(data, mapping);
	}

	return 0;
}


/* --------------------------------------------------------------------------
 * Control transactions
 *
 * To make extended set operations as atomic as the hardware allows, controls
 * are handled using begin/commit/rollback operations.
 *
 * At the beginning of a set request, uvc_ctrl_begin should be called to
 * initialize the request. This function acquires the control lock.
 *
 * When setting a control, the new value is stored in the control data field
 * at position UVC_CTRL_DATA_CURRENT. The control is then marked as dirty for
 * later processing. If the UVC and V4L2 control sizes differ, the current
 * value is loaded from the hardware before storing the new value in the data
 * field.
 *
 * After processing all controls in the transaction, uvc_ctrl_commit or
 * uvc_ctrl_rollback must be called to apply the pending changes to the
 * hardware or revert them. When applying changes, all controls marked as
 * dirty will be modified in the UVC device, and the dirty flag will be
 * cleared. When reverting controls, the control data field
 * UVC_CTRL_DATA_CURRENT is reverted to its previous value
 * (UVC_CTRL_DATA_BACKUP) for all dirty controls. Both functions release the
 * control lock.
 */
int uvc_ctrl_begin(struct uvc_video_device *video)
{
	return mutex_lock_interruptible(&video->ctrl_mutex) ? -ERESTARTSYS : 0;
}

static int uvc_ctrl_commit_entity(struct uvc_device *dev,
	struct uvc_entity *entity, int rollback)
{
	struct uvc_control *ctrl;
	unsigned int i;
	int ret;

	if (entity == NULL)
		return 0;

	for (i = 0; i < entity->ncontrols; ++i) {
		ctrl = &entity->controls[i];
		if (ctrl->info == NULL || !ctrl->dirty)
			continue;

		if (!rollback)
			ret = uvc_query_ctrl(dev, SET_CUR, ctrl->entity->id,
				dev->intfnum, ctrl->info->selector,
				uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
				ctrl->info->size);
		else
			ret = 0;

		if (rollback || ret < 0)
			memcpy(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
			       uvc_ctrl_data(ctrl, UVC_CTRL_DATA_BACKUP),
			       ctrl->info->size);

		if ((ctrl->info->flags & UVC_CONTROL_GET_CUR) == 0)
			ctrl->loaded = 0;

		ctrl->dirty = 0;

		if (ret < 0)
			return ret;
	}

	return 0;
}

int __uvc_ctrl_commit(struct uvc_video_device *video, int rollback)
{
	struct uvc_entity *entity;
	int ret = 0;

	/* Find the control. */
	ret = uvc_ctrl_commit_entity(video->dev, video->processing, rollback);
	if (ret < 0)
		goto done;

	list_for_each_entry(entity, &video->iterms, chain) {
		ret = uvc_ctrl_commit_entity(video->dev, entity, rollback);
		if (ret < 0)
			goto done;
	}

	list_for_each_entry(entity, &video->extensions, chain) {
		ret = uvc_ctrl_commit_entity(video->dev, entity, rollback);
		if (ret < 0)
			goto done;
	}

done:
	mutex_unlock(&video->ctrl_mutex);
	return ret;
}

int uvc_ctrl_get(struct uvc_video_device *video,
	struct v4l2_ext_control *xctrl)
{
	struct uvc_control *ctrl;
	struct uvc_control_mapping *mapping;
	struct uvc_menu_info *menu;
	unsigned int i;
	int ret;

	ctrl = uvc_find_control(video, xctrl->id, &mapping);
	if (ctrl == NULL || (ctrl->info->flags & UVC_CONTROL_GET_CUR) == 0)
		return -EINVAL;

	if (!ctrl->loaded) {
		ret = uvc_query_ctrl(video->dev, GET_CUR, ctrl->entity->id,
				video->dev->intfnum, ctrl->info->selector,
				uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
				ctrl->info->size);
		if (ret < 0)
			return ret;

		if ((ctrl->info->flags & UVC_CONTROL_AUTO_UPDATE) == 0)
			ctrl->loaded = 1;
	}

	xctrl->value = uvc_get_le_value(
		uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT), mapping);

	if (mapping->v4l2_type == V4L2_CTRL_TYPE_MENU) {
		menu = mapping->menu_info;
		for (i = 0; i < mapping->menu_count; ++i, ++menu) {
			if (menu->value == xctrl->value) {
				xctrl->value = i;
				break;
			}
		}
	}

	return 0;
}

int uvc_ctrl_set(struct uvc_video_device *video,
	struct v4l2_ext_control *xctrl)
{
	struct uvc_control *ctrl;
	struct uvc_control_mapping *mapping;
	s32 value = xctrl->value;
	int ret;

	ctrl = uvc_find_control(video, xctrl->id, &mapping);
	if (ctrl == NULL || (ctrl->info->flags & UVC_CONTROL_SET_CUR) == 0)
		return -EINVAL;

	if (mapping->v4l2_type == V4L2_CTRL_TYPE_MENU) {
		if (value < 0 || value >= mapping->menu_count)
			return -EINVAL;
		value = mapping->menu_info[value].value;
	}

	if (!ctrl->loaded && (ctrl->info->size * 8) != mapping->size) {
		if ((ctrl->info->flags & UVC_CONTROL_GET_CUR) == 0) {
			memset(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
				0, ctrl->info->size);
		} else {
			ret = uvc_query_ctrl(video->dev, GET_CUR,
				ctrl->entity->id, video->dev->intfnum,
				ctrl->info->selector,
				uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
				ctrl->info->size);
			if (ret < 0)
				return ret;
		}

		if ((ctrl->info->flags & UVC_CONTROL_AUTO_UPDATE) == 0)
			ctrl->loaded = 1;
	}

	if (!ctrl->dirty) {
		memcpy(uvc_ctrl_data(ctrl, UVC_CTRL_DATA_BACKUP),
		       uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT),
		       ctrl->info->size);
	}

	uvc_set_le_value(value,
		uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT), mapping);

	ctrl->dirty = 1;
	ctrl->modified = 1;
	return 0;
}

/* --------------------------------------------------------------------------
 * Dynamic controls