V4L/DVB (10104): uvcvideo: Add support for video output devices

Extend the range of supported UVC devices by allowing video output devices
matching the following structure:

TT_STREAMING -> VC_PROCESSING_UNIT -> VC_EXTENSION_UNIT{0,n} -> OTT_*

Video output devices are reported with the V4L2_CAP_VIDEO_OUTPUT capability
flag and are subject to the same restrictions as video input devices.

Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 75 insertions, 34 deletions

diff --git a/drivers/media/video/uvc/uvc_driver.c b/drivers/media/video/uvc/uvc_driver.c
index 18a61928f4f6..89d8bd10a852 100644
--- a/drivers/media/video/uvc/uvc_driver.c
+++ b/drivers/media/video/uvc/uvc_driver.c
@@ -12,8 +12,8 @@
  */
 
 /*
- * This driver aims to support video input devices compliant with the 'USB
- * Video Class' specification.
+ * This driver aims to support video input and ouput devices compliant with the
+ * 'USB Video Class' specification.
  *
  * The driver doesn't support the deprecated v4l1 interface. It implements the
  * mmap capture method only, and doesn't do any image format conversion in
@@ -609,46 +609,55 @@ static int uvc_parse_streaming(struct uvc_device *dev,
         }
 
         /* Parse the header descriptor. */
-        if (buffer[2] == VS_OUTPUT_HEADER) {
+        switch (buffer[2]) {
+        case VS_OUTPUT_HEADER:
+                streaming->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
+                size = 9;
+                break;
+
+        case VS_INPUT_HEADER:
+                streaming->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+                size = 13;
+                break;
+
+        default:
                 uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming interface "
-                        "%d OUTPUT HEADER descriptor is not supported.\n",
-                        dev->udev->devnum, alts->desc.bInterfaceNumber);
+                        "%d HEADER descriptor not found.\n", dev->udev->devnum,
+                        alts->desc.bInterfaceNumber);
                 goto error;
-        } else if (buffer[2] == VS_INPUT_HEADER) {
-                p = buflen >= 5 ? buffer[3] : 0;
-                n = buflen >= 12 ? buffer[12] : 0;
+        }
 
-                if (buflen < 13 + p*n || buffer[2] != VS_INPUT_HEADER) {
-                        uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming "
-                                "interface %d INPUT HEADER descriptor is "
-                                "invalid.\n", dev->udev->devnum,
-                                alts->desc.bInterfaceNumber);
-                        goto error;
-                }
+        p = buflen >= 4 ? buffer[3] : 0;
+        n = buflen >= size ? buffer[size-1] : 0;
+
+        if (buflen < size + p*n) {
+                uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming "
+                        "interface %d HEADER descriptor is invalid.\n",
+                        dev->udev->devnum, alts->desc.bInterfaceNumber);
+                goto error;
+        }
 
-                streaming->header.bNumFormats = p;
-                streaming->header.bEndpointAddress = buffer[6];
+        streaming->header.bNumFormats = p;
+        streaming->header.bEndpointAddress = buffer[6];
+        if (buffer[2] == VS_INPUT_HEADER) {
                 streaming->header.bmInfo = buffer[7];
                 streaming->header.bTerminalLink = buffer[8];
                 streaming->header.bStillCaptureMethod = buffer[9];
                 streaming->header.bTriggerSupport = buffer[10];
                 streaming->header.bTriggerUsage = buffer[11];
-                streaming->header.bControlSize = n;
-
-                streaming->header.bmaControls = kmalloc(p*n, GFP_KERNEL);
-                if (streaming->header.bmaControls == NULL) {
-                        ret = -ENOMEM;
-                        goto error;
-                }
-
-                memcpy(streaming->header.bmaControls, &buffer[13], p*n);
         } else {
-                uvc_trace(UVC_TRACE_DESCR, "device %d videostreaming interface "
-                        "%d HEADER descriptor not found.\n", dev->udev->devnum,
-                        alts->desc.bInterfaceNumber);
+                streaming->header.bTerminalLink = buffer[7];
+        }
+        streaming->header.bControlSize = n;
+
+        streaming->header.bmaControls = kmalloc(p*n, GFP_KERNEL);
+        if (streaming->header.bmaControls == NULL) {
+                ret = -ENOMEM;
                 goto error;
         }
 
+        memcpy(streaming->header.bmaControls, &buffer[size], p*n);
+
         buflen -= buffer[0];
         buffer += buffer[0];
 
@@ -1258,6 +1267,26 @@ static int uvc_scan_chain_entity(struct uvc_video_device *video,
                 list_add_tail(&entity->chain, &video->iterms);
                 break;
 
+        case TT_STREAMING:
+                if (uvc_trace_param & UVC_TRACE_PROBE)
+                        printk(" <- IT %d\n", entity->id);
+
+                if (!UVC_ENTITY_IS_ITERM(entity)) {
+                        uvc_trace(UVC_TRACE_DESCR, "Unsupported input "
+                                "terminal %u.\n", entity->id);
+                        return -1;
+                }
+
+                if (video->sterm != NULL) {
+                        uvc_trace(UVC_TRACE_DESCR, "Found multiple streaming "
+                                "entities in chain.\n");
+                        return -1;
+                }
+
+                list_add_tail(&entity->chain, &video->iterms);
+                video->sterm = entity;
+                break;
+
         default:
                 uvc_trace(UVC_TRACE_DESCR, "Unsupported entity type "
                         "0x%04x found in chain.\n", UVC_ENTITY_TYPE(entity));
@@ -1368,6 +1397,10 @@ static int uvc_scan_chain(struct uvc_video_device *video)
 
         entity = video->oterm;
         uvc_trace(UVC_TRACE_PROBE, "Scanning UVC chain: OT %d", entity->id);
+
+        if (UVC_ENTITY_TYPE(entity) == TT_STREAMING)
+                video->sterm = entity;
+
         id = entity->output.bSourceID;
         while (id != 0) {
                 prev = entity;
@@ -1396,8 +1429,11 @@ static int uvc_scan_chain(struct uvc_video_device *video)
                         return id;
         }
 
-        /* Initialize the video buffers queue. */
-        uvc_queue_init(&video->queue);
+        if (video->sterm == NULL) {
+                uvc_trace(UVC_TRACE_DESCR, "No streaming entity found in "
+                        "chain.\n");
+                return -1;
+        }
 
         return 0;
 }
@@ -1408,7 +1444,8 @@ static int uvc_scan_chain(struct uvc_video_device *video)
  * The driver currently supports a single video device per control interface
  * only. The terminal and units must match the following structure:
  *
- * ITT_CAMERA -> VC_PROCESSING_UNIT -> VC_EXTENSION_UNIT{0,n} -> TT_STREAMING
+ * ITT_* -> VC_PROCESSING_UNIT -> VC_EXTENSION_UNIT{0,n} -> TT_STREAMING
+ * TT_STREAMING -> VC_PROCESSING_UNIT -> VC_EXTENSION_UNIT{0,n} -> OTT_*
  *
  * The Extension Units, if present, must have a single input pin. The
  * Processing Unit and Extension Units can be in any order. Additional
@@ -1425,7 +1462,7 @@ static int uvc_register_video(struct uvc_device *dev)
         list_for_each_entry(term, &dev->entities, list) {
                 struct uvc_streaming *streaming;
 
-                if (UVC_ENTITY_TYPE(term) != TT_STREAMING)
+                if (!UVC_ENTITY_IS_TERM(term) || !UVC_ENTITY_IS_OTERM(term))
                         continue;
 
                 memset(&dev->video, 0, sizeof dev->video);
@@ -1438,7 +1475,8 @@ static int uvc_register_video(struct uvc_device *dev)
                         continue;
 
                 list_for_each_entry(streaming, &dev->streaming, list) {
-                        if (streaming->header.bTerminalLink == term->id) {
+                        if (streaming->header.bTerminalLink ==
+                            dev->video.sterm->id) {
                                 dev->video.streaming = streaming;
                                 found = 1;
                                 break;
@@ -1464,6 +1502,9 @@ static int uvc_register_video(struct uvc_device *dev)
                 printk(" -> %d).\n", dev->video.oterm->id);
         }
 
+        /* Initialize the video buffers queue. */
+        uvc_queue_init(&dev->video.queue, dev->video.streaming->type);
+
         /* Initialize the streaming interface with default streaming
          * parameters.
          */