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Commit e5225c82 authored by Guennadi Liakhovetski's avatar Guennadi Liakhovetski Committed by Mauro Carvalho Chehab
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media: uvcvideo: Send a control event when a Control Change interrupt arrives



UVC defines a method of handling asynchronous controls, which sends a
USB packet over the interrupt pipe. This patch implements support for
such packets by sending a control event to the user. Since this can
involve USB traffic and, therefore, scheduling, this has to be done
in a work queue.

Signed-off-by: default avatarGuennadi Liakhovetski <guennadi.liakhovetski@intel.com>
Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
parent 8e7a1dbc
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+161 −50
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@
#include <linux/videodev2.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/atomic.h>
#include <media/v4l2-ctrls.h>

@@ -971,12 +972,30 @@ static int uvc_ctrl_populate_cache(struct uvc_video_chain *chain,
	return 0;
}

static s32 __uvc_ctrl_get_value(struct uvc_control_mapping *mapping,
				const u8 *data)
{
	s32 value = mapping->get(mapping, UVC_GET_CUR, data);

	if (mapping->v4l2_type == V4L2_CTRL_TYPE_MENU) {
		struct uvc_menu_info *menu = mapping->menu_info;
		unsigned int i;

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

	return value;
}

static int __uvc_ctrl_get(struct uvc_video_chain *chain,
	struct uvc_control *ctrl, struct uvc_control_mapping *mapping,
	s32 *value)
{
	struct uvc_menu_info *menu;
	unsigned int i;
	int ret;

	if ((ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR) == 0)
@@ -993,19 +1012,9 @@ static int __uvc_ctrl_get(struct uvc_video_chain *chain,
		ctrl->loaded = 1;
	}

	*value = mapping->get(mapping, UVC_GET_CUR,
	*value = __uvc_ctrl_get_value(mapping,
				uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT));

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

	return 0;
}

@@ -1216,53 +1225,135 @@ static void uvc_ctrl_fill_event(struct uvc_video_chain *chain,
	ev->u.ctrl.default_value = v4l2_ctrl.default_value;
}

static void uvc_ctrl_send_event(struct uvc_fh *handle,
	struct uvc_control *ctrl, struct uvc_control_mapping *mapping,
	s32 value, u32 changes)
/*
 * Send control change events to all subscribers for the @ctrl control. By
 * default the subscriber that generated the event, as identified by @handle,
 * is not notified unless it has set the V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK flag.
 * @handle can be NULL for asynchronous events related to auto-update controls,
 * in which case all subscribers are notified.
 */
static void uvc_ctrl_send_event(struct uvc_video_chain *chain,
	struct uvc_fh *handle, struct uvc_control *ctrl,
	struct uvc_control_mapping *mapping, s32 value, u32 changes)
{
	struct v4l2_fh *originator = handle ? &handle->vfh : NULL;
	struct v4l2_subscribed_event *sev;
	struct v4l2_event ev;

	if (list_empty(&mapping->ev_subs))
		return;

	uvc_ctrl_fill_event(handle->chain, &ev, ctrl, mapping, value, changes);
	uvc_ctrl_fill_event(chain, &ev, ctrl, mapping, value, changes);

	list_for_each_entry(sev, &mapping->ev_subs, node) {
		if (sev->fh != &handle->vfh ||
		if (sev->fh != originator ||
		    (sev->flags & V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK) ||
		    (changes & V4L2_EVENT_CTRL_CH_FLAGS))
			v4l2_event_queue_fh(sev->fh, &ev);
	}
}

static void uvc_ctrl_send_slave_event(struct uvc_fh *handle,
	struct uvc_control *master, u32 slave_id,
	const struct v4l2_ext_control *xctrls, unsigned int xctrls_count)
/*
 * Send control change events for the slave of the @master control identified
 * by the V4L2 ID @slave_id. The @handle identifies the event subscriber that
 * generated the event and may be NULL for auto-update events.
 */
static void uvc_ctrl_send_slave_event(struct uvc_video_chain *chain,
	struct uvc_fh *handle, struct uvc_control *master, u32 slave_id)
{
	struct uvc_control_mapping *mapping = NULL;
	struct uvc_control *ctrl = NULL;
	u32 changes = V4L2_EVENT_CTRL_CH_FLAGS;
	unsigned int i;
	s32 val = 0;

	/*
	 * We can skip sending an event for the slave if the slave
	 * is being modified in the same transaction.
	 */
	for (i = 0; i < xctrls_count; i++) {
		if (xctrls[i].id == slave_id)
			return;
	}

	__uvc_find_control(master->entity, slave_id, &mapping, &ctrl, 0);
	if (ctrl == NULL)
		return;

	if (__uvc_ctrl_get(handle->chain, ctrl, mapping, &val) == 0)
	if (__uvc_ctrl_get(chain, ctrl, mapping, &val) == 0)
		changes |= V4L2_EVENT_CTRL_CH_VALUE;

	uvc_ctrl_send_event(handle, ctrl, mapping, val, changes);
	uvc_ctrl_send_event(chain, handle, ctrl, mapping, val, changes);
}

static void uvc_ctrl_status_event_work(struct work_struct *work)
{
	struct uvc_device *dev = container_of(work, struct uvc_device,
					      async_ctrl.work);
	struct uvc_ctrl_work *w = &dev->async_ctrl;
	struct uvc_video_chain *chain = w->chain;
	struct uvc_control_mapping *mapping;
	struct uvc_control *ctrl = w->ctrl;
	struct uvc_fh *handle;
	unsigned int i;
	int ret;

	mutex_lock(&chain->ctrl_mutex);

	handle = ctrl->handle;
	ctrl->handle = NULL;

	list_for_each_entry(mapping, &ctrl->info.mappings, list) {
		s32 value = __uvc_ctrl_get_value(mapping, w->data);

		/*
		 * handle may be NULL here if the device sends auto-update
		 * events without a prior related control set from userspace.
		 */
		for (i = 0; i < ARRAY_SIZE(mapping->slave_ids); ++i) {
			if (!mapping->slave_ids[i])
				break;

			uvc_ctrl_send_slave_event(chain, handle, ctrl,
						  mapping->slave_ids[i]);
		}

		uvc_ctrl_send_event(chain, handle, ctrl, mapping, value,
				    V4L2_EVENT_CTRL_CH_VALUE);
	}

	mutex_unlock(&chain->ctrl_mutex);

	/* Resubmit the URB. */
	w->urb->interval = dev->int_ep->desc.bInterval;
	ret = usb_submit_urb(w->urb, GFP_KERNEL);
	if (ret < 0)
		uvc_printk(KERN_ERR, "Failed to resubmit status URB (%d).\n",
			   ret);
}

bool uvc_ctrl_status_event(struct urb *urb, struct uvc_video_chain *chain,
			   struct uvc_control *ctrl, const u8 *data)
{
	struct uvc_device *dev = chain->dev;
	struct uvc_ctrl_work *w = &dev->async_ctrl;

	if (list_empty(&ctrl->info.mappings)) {
		ctrl->handle = NULL;
		return false;
	}

	w->data = data;
	w->urb = urb;
	w->chain = chain;
	w->ctrl = ctrl;

	schedule_work(&w->work);

	return true;
}

static bool uvc_ctrl_xctrls_has_control(const struct v4l2_ext_control *xctrls,
					unsigned int xctrls_count, u32 id)
{
	unsigned int i;

	for (i = 0; i < xctrls_count; ++i) {
		if (xctrls[i].id == id)
			return true;
	}

	return false;
}

static void uvc_ctrl_send_events(struct uvc_fh *handle,
@@ -1277,29 +1368,39 @@ static void uvc_ctrl_send_events(struct uvc_fh *handle,
	for (i = 0; i < xctrls_count; ++i) {
		ctrl = uvc_find_control(handle->chain, xctrls[i].id, &mapping);

		if (ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS)
			/* Notification will be sent from an Interrupt event. */
			continue;

		for (j = 0; j < ARRAY_SIZE(mapping->slave_ids); ++j) {
			if (!mapping->slave_ids[j])
			u32 slave_id = mapping->slave_ids[j];

			if (!slave_id)
				break;
			uvc_ctrl_send_slave_event(handle, ctrl,
						  mapping->slave_ids[j],
						  xctrls, xctrls_count);

			/*
			 * We can skip sending an event for the slave if the
			 * slave is being modified in the same transaction.
			 */
			if (uvc_ctrl_xctrls_has_control(xctrls, xctrls_count,
							slave_id))
				continue;

			uvc_ctrl_send_slave_event(handle->chain, handle, ctrl,
						  slave_id);
		}

		/*
		 * If the master is being modified in the same transaction
		 * flags may change too.
		 */
		if (mapping->master_id) {
			for (j = 0; j < xctrls_count; j++) {
				if (xctrls[j].id == mapping->master_id) {
		if (mapping->master_id &&
		    uvc_ctrl_xctrls_has_control(xctrls, xctrls_count,
						mapping->master_id))
			changes |= V4L2_EVENT_CTRL_CH_FLAGS;
					break;
				}
			}
		}

		uvc_ctrl_send_event(handle, ctrl, mapping, xctrls[i].value,
				    changes);
		uvc_ctrl_send_event(handle->chain, handle, ctrl, mapping,
				    xctrls[i].value, changes);
	}
}

@@ -1472,9 +1573,10 @@ int uvc_ctrl_get(struct uvc_video_chain *chain,
	return __uvc_ctrl_get(chain, ctrl, mapping, &xctrl->value);
}

int uvc_ctrl_set(struct uvc_video_chain *chain,
int uvc_ctrl_set(struct uvc_fh *handle,
	struct v4l2_ext_control *xctrl)
{
	struct uvc_video_chain *chain = handle->chain;
	struct uvc_control *ctrl;
	struct uvc_control_mapping *mapping;
	s32 value;
@@ -1581,6 +1683,9 @@ int uvc_ctrl_set(struct uvc_video_chain *chain,
	mapping->set(mapping, value,
		uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT));

	if (ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS)
		ctrl->handle = handle;

	ctrl->dirty = 1;
	ctrl->modified = 1;
	return 0;
@@ -1612,7 +1717,9 @@ static int uvc_ctrl_get_flags(struct uvc_device *dev,
			    |  (data[0] & UVC_CONTROL_CAP_SET ?
				UVC_CTRL_FLAG_SET_CUR : 0)
			    |  (data[0] & UVC_CONTROL_CAP_AUTOUPDATE ?
				UVC_CTRL_FLAG_AUTO_UPDATE : 0);
				UVC_CTRL_FLAG_AUTO_UPDATE : 0)
			    |  (data[0] & UVC_CONTROL_CAP_ASYNCHRONOUS ?
				UVC_CTRL_FLAG_ASYNCHRONOUS : 0);

	kfree(data);
	return ret;
@@ -2173,6 +2280,8 @@ int uvc_ctrl_init_device(struct uvc_device *dev)
	struct uvc_entity *entity;
	unsigned int i;

	INIT_WORK(&dev->async_ctrl.work, uvc_ctrl_status_event_work);

	/* Walk the entities list and instantiate controls */
	list_for_each_entry(entity, &dev->entities, list) {
		struct uvc_control *ctrl;
@@ -2241,6 +2350,8 @@ void uvc_ctrl_cleanup_device(struct uvc_device *dev)
	struct uvc_entity *entity;
	unsigned int i;

	cancel_work_sync(&dev->async_ctrl.work);

	/* Free controls and control mappings for all entities. */
	list_for_each_entry(entity, &dev->entities, list) {
		for (i = 0; i < entity->ncontrols; ++i) {
+107 −14
Original line number Diff line number Diff line
@@ -78,7 +78,24 @@ static void uvc_input_report_key(struct uvc_device *dev, unsigned int code,
/* --------------------------------------------------------------------------
 * Status interrupt endpoint
 */
static void uvc_event_streaming(struct uvc_device *dev, u8 *data, int len)
struct uvc_streaming_status {
	u8	bStatusType;
	u8	bOriginator;
	u8	bEvent;
	u8	bValue[];
} __packed;

struct uvc_control_status {
	u8	bStatusType;
	u8	bOriginator;
	u8	bEvent;
	u8	bSelector;
	u8	bAttribute;
	u8	bValue[];
} __packed;

static void uvc_event_streaming(struct uvc_device *dev,
				struct uvc_streaming_status *status, int len)
{
	if (len < 3) {
		uvc_trace(UVC_TRACE_STATUS, "Invalid streaming status event "
@@ -86,31 +103,97 @@ static void uvc_event_streaming(struct uvc_device *dev, u8 *data, int len)
		return;
	}

	if (data[2] == 0) {
	if (status->bEvent == 0) {
		if (len < 4)
			return;
		uvc_trace(UVC_TRACE_STATUS, "Button (intf %u) %s len %d\n",
			data[1], data[3] ? "pressed" : "released", len);
		uvc_input_report_key(dev, KEY_CAMERA, data[3]);
			  status->bOriginator,
			  status->bValue[0] ? "pressed" : "released", len);
		uvc_input_report_key(dev, KEY_CAMERA, status->bValue[0]);
	} else {
		uvc_trace(UVC_TRACE_STATUS,
			  "Stream %u error event %02x len %d.\n",
			  data[1], data[2], len);
			  status->bOriginator, status->bEvent, len);
	}
}

static void uvc_event_control(struct uvc_device *dev, u8 *data, int len)
#define UVC_CTRL_VALUE_CHANGE	0
#define UVC_CTRL_INFO_CHANGE	1
#define UVC_CTRL_FAILURE_CHANGE	2
#define UVC_CTRL_MIN_CHANGE	3
#define UVC_CTRL_MAX_CHANGE	4

static struct uvc_control *uvc_event_entity_find_ctrl(struct uvc_entity *entity,
						      u8 selector)
{
	struct uvc_control *ctrl;
	unsigned int i;

	for (i = 0, ctrl = entity->controls; i < entity->ncontrols; i++, ctrl++)
		if (ctrl->info.selector == selector)
			return ctrl;

	return NULL;
}

static struct uvc_control *uvc_event_find_ctrl(struct uvc_device *dev,
					const struct uvc_control_status *status,
					struct uvc_video_chain **chain)
{
	list_for_each_entry((*chain), &dev->chains, list) {
		struct uvc_entity *entity;
		struct uvc_control *ctrl;

		list_for_each_entry(entity, &(*chain)->entities, chain) {
			if (entity->id != status->bOriginator)
				continue;

			ctrl = uvc_event_entity_find_ctrl(entity,
							  status->bSelector);
			if (ctrl)
				return ctrl;
		}
	}

	return NULL;
}

static bool uvc_event_control(struct urb *urb,
			      const struct uvc_control_status *status, int len)
{
	char *attrs[3] = { "value", "info", "failure" };
	static const char *attrs[] = { "value", "info", "failure", "min", "max" };
	struct uvc_device *dev = urb->context;
	struct uvc_video_chain *chain;
	struct uvc_control *ctrl;

	if (len < 6 || data[2] != 0 || data[4] > 2) {
	if (len < 6 || status->bEvent != 0 ||
	    status->bAttribute >= ARRAY_SIZE(attrs)) {
		uvc_trace(UVC_TRACE_STATUS, "Invalid control status event "
				"received.\n");
		return;
		return false;
	}

	uvc_trace(UVC_TRACE_STATUS, "Control %u/%u %s change len %d.\n",
		data[1], data[3], attrs[data[4]], len);
		  status->bOriginator, status->bSelector,
		  attrs[status->bAttribute], len);

	/* Find the control. */
	ctrl = uvc_event_find_ctrl(dev, status, &chain);
	if (!ctrl)
		return false;

	switch (status->bAttribute) {
	case UVC_CTRL_VALUE_CHANGE:
		return uvc_ctrl_status_event(urb, chain, ctrl, status->bValue);

	case UVC_CTRL_INFO_CHANGE:
	case UVC_CTRL_FAILURE_CHANGE:
	case UVC_CTRL_MIN_CHANGE:
	case UVC_CTRL_MAX_CHANGE:
		break;
	}

	return false;
}

static void uvc_status_complete(struct urb *urb)
@@ -138,13 +221,23 @@ static void uvc_status_complete(struct urb *urb)
	len = urb->actual_length;
	if (len > 0) {
		switch (dev->status[0] & 0x0f) {
		case UVC_STATUS_TYPE_CONTROL:
			uvc_event_control(dev, dev->status, len);
		case UVC_STATUS_TYPE_CONTROL: {
			struct uvc_control_status *status =
				(struct uvc_control_status *)dev->status;

			if (uvc_event_control(urb, status, len))
				/* The URB will be resubmitted in work context. */
				return;
			break;
		}

		case UVC_STATUS_TYPE_STREAMING:
			uvc_event_streaming(dev, dev->status, len);
		case UVC_STATUS_TYPE_STREAMING: {
			struct uvc_streaming_status *status =
				(struct uvc_streaming_status *)dev->status;

			uvc_event_streaming(dev, status, len);
			break;
		}

		default:
			uvc_trace(UVC_TRACE_STATUS, "Unknown status event "
+2 −2
Original line number Diff line number Diff line
@@ -994,7 +994,7 @@ static int uvc_ioctl_s_ctrl(struct file *file, void *fh,
	if (ret < 0)
		return ret;

	ret = uvc_ctrl_set(chain, &xctrl);
	ret = uvc_ctrl_set(handle, &xctrl);
	if (ret < 0) {
		uvc_ctrl_rollback(handle);
		return ret;
@@ -1069,7 +1069,7 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle,
		return ret;

	for (i = 0; i < ctrls->count; ++ctrl, ++i) {
		ret = uvc_ctrl_set(chain, ctrl);
		ret = uvc_ctrl_set(handle, ctrl);
		if (ret < 0) {
			uvc_ctrl_rollback(handle);
			ctrls->error_idx = commit ? ctrls->count : i;
+14 −1
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@
#include <linux/usb/video.h>
#include <linux/uvcvideo.h>
#include <linux/videodev2.h>
#include <linux/workqueue.h>
#include <media/media-device.h>
#include <media/v4l2-device.h>
#include <media/v4l2-event.h>
@@ -259,6 +260,8 @@ struct uvc_control {
	   initialized:1;

	u8 *uvc_data;

	struct uvc_fh *handle;	/* File handle that last changed the control. */
};

struct uvc_format_desc {
@@ -603,6 +606,14 @@ struct uvc_device {
	u8 *status;
	struct input_dev *input;
	char input_phys[64];

	struct uvc_ctrl_work {
		struct work_struct work;
		struct urb *urb;
		struct uvc_video_chain *chain;
		struct uvc_control *ctrl;
		const void *data;
	} async_ctrl;
};

enum uvc_handle_state {
@@ -756,6 +767,8 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
int uvc_ctrl_init_device(struct uvc_device *dev);
void uvc_ctrl_cleanup_device(struct uvc_device *dev);
int uvc_ctrl_restore_values(struct uvc_device *dev);
bool uvc_ctrl_status_event(struct urb *urb, struct uvc_video_chain *chain,
			   struct uvc_control *ctrl, const u8 *data);

int uvc_ctrl_begin(struct uvc_video_chain *chain);
int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback,
@@ -773,7 +786,7 @@ static inline int uvc_ctrl_rollback(struct uvc_fh *handle)
}

int uvc_ctrl_get(struct uvc_video_chain *chain, struct v4l2_ext_control *xctrl);
int uvc_ctrl_set(struct uvc_video_chain *chain, struct v4l2_ext_control *xctrl);
int uvc_ctrl_set(struct uvc_fh *handle, struct v4l2_ext_control *xctrl);

int uvc_xu_ctrl_query(struct uvc_video_chain *chain,
		      struct uvc_xu_control_query *xqry);
+2 −0
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@
#define UVC_CTRL_FLAG_RESTORE		(1 << 6)
/* Control can be updated by the camera. */
#define UVC_CTRL_FLAG_AUTO_UPDATE	(1 << 7)
/* Control supports asynchronous reporting */
#define UVC_CTRL_FLAG_ASYNCHRONOUS	(1 << 8)

#define UVC_CTRL_FLAG_GET_RANGE \
	(UVC_CTRL_FLAG_GET_CUR | UVC_CTRL_FLAG_GET_MIN | \