usb: host: uvc: loop through every descriptor

Loop through each of the VideoStreaming and VideoControl descriptor
to parse them.

Signed-off-by: Josuah Demangeon <[email protected]>

Author: Josuah Demangeon

subsys/usb/host/class/usbh_uvc.c

@@ -33,8 +33,8 @@
 
 LOG_MODULE_REGISTER(usbh_uvc, CONFIG_USBH_VIDEO_LOG_LEVEL);
 
-struct usbh_uvc_config {
-	struct usbh_contex *uhs_ctx;
+struct usbh_uvc_data {
+	int todo;
 };
 
 static int usbh_uvc_request(struct usbh_contex *const uhs_ctx, struct uhc_transfer *const xfer,
@@ -45,28 +45,104 @@ static int usbh_uvc_request(struct usbh_contex *const uhs_ctx, struct uhc_transf
 	return 0;
 }
 
+static int usbh_uvc_parse_control_desc(struct usbh_contex *const uhs_ctx,
+				       struct usbh_uvc_data *const uvc,
+				       struct usb_if_descriptor *const if_control)
+{
+	struct uvc_if_descriptor *desc = (void *)if_control;
+
+	LOG_INF("%s", __func__);
+
+	while (desc->bLength != 0) {
+		/* Skip the interface descriptor or switch to the next descriptor */
+		desc = (void *)((uint8_t *)desc + desc->bLength);
+
+		if (desc->bDescriptorType == USB_DESC_INTERFACE ||
+		    desc->bDescriptorType == USB_DESC_INTERFACE_ASSOC ||
+		    desc->bDescriptorType == 0) {
+			break;
+		} else if (desc->bDescriptorType == USB_DESC_CS_INTERFACE) {
+			;
+		} else if (desc->bDescriptorType == USB_DESC_CS_ENDPOINT) {
+			;
+		}
+
+		LOG_INF("bLength %u, bDescriptorType %u, bDescriptorSubtype %u",
+			desc->bDescriptorType, desc->bDescriptorSubtype, desc->bLength);
+	}
+
+	return 0;
+}
+
+static int usbh_uvc_parse_streaming_desc(struct usbh_contex *const uhs_ctx,
+					 struct usbh_uvc_data *const uvc,
+					 struct usb_if_descriptor *const if_streaming)
+{
+	struct uvc_if_descriptor *desc = (void *)if_streaming;
+
+	LOG_INF("%s", __func__);
+
+	while (desc->bLength != 0) {
+		/* Skip the interface descriptor or switch to the next descriptor */
+		desc = (void *)((uint8_t *)desc + desc->bLength);
+
+		if (desc->bDescriptorType == USB_DESC_INTERFACE ||
+		    desc->bDescriptorType == USB_DESC_INTERFACE_ASSOC ||
+		    desc->bDescriptorType == 0) {
+			break;
+		} else if (desc->bDescriptorType == USB_DESC_CS_INTERFACE) {
+			;
+		} else if (desc->bDescriptorType == USB_DESC_CS_ENDPOINT) {
+			;
+		}
+
+		LOG_INF("bLength %u, bDescriptorType %u, bDescriptorSubtype %u",
+			desc->bDescriptorType, desc->bDescriptorSubtype, desc->bLength);
+	}
+
+	return 0;
+}
+
 static int usbh_uvc_connected(struct usbh_contex *const uhs_ctx)
 {
 	struct usb_device *const udev = uhs_ctx->root;
-	const size_t len = 512;
-	struct net_buf *buf;
+	struct usbh_uvc_data *const uvc = NULL;
+	struct usb_if_descriptor *if_control;
+	struct usb_if_descriptor *if_streaming;
 	int ret;
 
 	LOG_INF("%p", uhs_ctx);
 
-	buf = usbh_xfer_buf_alloc(udev, len);
-	if (buf == NULL) {
-		LOG_ERR("Failed to allocate a host transfer buffer");
-		return -ENOMEM;
+	/* TODO only scan through the interfaces assigned to this class by usbh_class.c */
+	for (unsigned int i = 0; udev->ifaces[i].dhp != NULL; i++) {
+		struct usb_if_descriptor *if_desc = (void *)udev->ifaces[i].dhp;
+
+		if (if_desc->bInterfaceClass == USB_BCC_VIDEO &&
+		    if_desc->bInterfaceSubClass == UVC_SC_VIDEOCONTROL) {
+			if_control = if_desc;
+		}
+
+		if (if_desc->bInterfaceClass == USB_BCC_VIDEO &&
+		    if_desc->bInterfaceSubClass == UVC_SC_VIDEOSTREAMING) {
+			if_streaming = if_desc;
+		}
 	}
 
-	ret = usbh_req_desc(udev, USB_DESC_DEVICE, 0, 0, len, buf);
+	if (if_streaming == NULL || if_control == NULL) {
+		LOG_ERR("Video Streaming %p or Control %p interface missing",
+			if_streaming, if_control);
+		return -EINVAL;
+	}
+
+	ret = usbh_uvc_parse_control_desc(uhs_ctx, uvc, if_control);
 	if (ret != 0) {
-		LOG_ERR("Failed to request descriptor");
 		return ret;
 	}
 
-	LOG_HEXDUMP_INF(buf->data, buf->len, "buf");
+	ret = usbh_uvc_parse_streaming_desc(uhs_ctx, uvc, if_streaming);
+	if (ret != 0) {
+		return ret;
+	}
 
 	return 0;
 }