From: Kirill A. Korinsky <kirill@korins.ky>
Subject: sys/xhci: suppoort USB3 speeds
To: OpenBSD tech <tech@openbsd.org>
Cc: Marcus Glocker <mglocker@openbsd.org>
Date: Thu, 27 Feb 2025 20:21:25 +0100

tech@,

I'd like to add support of USB3 speeds to XHCI driver.

This diff was tested on Snapdragon SoC:

	xhci0 at qcdwusb0, xHCI 1.10
	usb0 at xhci0: USB revision 3.0
	uhub0 at usb0 configuration 1 interface 0 "Generic xHCI root hub" rev 3.00/1.00 addr 1

I also used diff: https://marc.info/?l=openbsd-tech&m=174032299500347&w=2
and switched Elgato Facecam Pro to isochronous mode with streaming
3840x2160 30fps with 33740 isoc frames / packets.

It works.

Ok?

Index: sys/dev/usb/usb_subr.c
===================================================================
RCS file: /home/cvs/src/sys/dev/usb/usb_subr.c,v
diff -u -p -r1.163 usb_subr.c
--- sys/dev/usb/usb_subr.c	23 May 2024 03:21:09 -0000	1.163
+++ sys/dev/usb/usb_subr.c	27 Feb 2025 18:49:51 -0000
@@ -514,7 +514,8 @@ int
 usbd_parse_idesc(struct usbd_device *dev, struct usbd_interface *ifc)
 {
 #define ed ((usb_endpoint_descriptor_t *)p)
-	char *p, *end;
+#define essd ((usb_endpoint_ss_comp_descriptor_t *)pp)
+	char *p, *pp, *end;
 	int i;

 	p = (char *)ifc->idesc + ifc->idesc->bLength;
@@ -534,6 +535,11 @@ usbd_parse_idesc(struct usbd_device *dev
 		if (p >= end)
 			return (-1);

+		pp = p + ed->bLength;
+		if (pp >= end || essd->bLength == 0 ||
+		    essd->bDescriptorType != UDESC_ENDPOINT_SS_COMP)
+			pp = NULL;
+
 		if (dev->speed == USB_SPEED_HIGH) {
 			unsigned int mps;

@@ -557,6 +563,7 @@ usbd_parse_idesc(struct usbd_device *dev
 		}

 		ifc->endpoints[i].edesc = ed;
+		ifc->endpoints[i].esscd = essd;
 		ifc->endpoints[i].refcnt = 0;
 		ifc->endpoints[i].savedtoggle = 0;
 		p += ed->bLength;
@@ -564,6 +571,7 @@ usbd_parse_idesc(struct usbd_device *dev

 	return (0);
 #undef ed
+#undef essd
 }

 void
Index: sys/dev/usb/usbdivar.h
===================================================================
RCS file: /home/cvs/src/sys/dev/usb/usbdivar.h,v
diff -u -p -r1.84 usbdivar.h
--- sys/dev/usb/usbdivar.h	8 Oct 2024 19:42:31 -0000	1.84
+++ sys/dev/usb/usbdivar.h	27 Feb 2025 18:48:11 -0000
@@ -55,6 +55,7 @@ struct usbd_pipe;

 struct usbd_endpoint {
 	usb_endpoint_descriptor_t *edesc;
+	usb_endpoint_ss_comp_descriptor_t *esscd;
 	int			refcnt;
 	int			savedtoggle;
 };
Index: sys/dev/usb/xhci.c
===================================================================
RCS file: /home/cvs/src/sys/dev/usb/xhci.c,v
diff -u -p -r1.135 xhci.c
--- sys/dev/usb/xhci.c	8 Oct 2024 19:42:31 -0000	1.135
+++ sys/dev/usb/xhci.c	27 Feb 2025 18:51:05 -0000
@@ -1355,6 +1355,7 @@ static inline uint32_t
 xhci_get_txinfo(struct xhci_softc *sc, struct usbd_pipe *pipe)
 {
 	usb_endpoint_descriptor_t *ed = pipe->endpoint->edesc;
+	usb_endpoint_ss_comp_descriptor_t *esscd = pipe->endpoint->esscd;
 	uint32_t mep, atl, mps = UGETW(ed->wMaxPacketSize);

 	switch (UE_GET_XFERTYPE(ed->bmAttributes)) {
@@ -1364,8 +1365,10 @@ xhci_get_txinfo(struct xhci_softc *sc, s
 		break;
 	case UE_INTERRUPT:
 	case UE_ISOCHRONOUS:
-		if (pipe->device->speed == USB_SPEED_SUPER) {
-			/*  XXX Read the companion descriptor */
+		if (esscd && pipe->device->speed >= USB_SPEED_SUPER) {
+			mep = UGETW(esscd->wBytesPerInterval);
+			atl = mep;
+			break;
 		}

 		mep = (UE_GET_TRANS(mps) + 1) * UE_GET_SIZE(mps);
@@ -1441,6 +1444,7 @@ uint32_t
 xhci_pipe_maxburst(struct usbd_pipe *pipe)
 {
 	usb_endpoint_descriptor_t *ed = pipe->endpoint->edesc;
+	usb_endpoint_ss_comp_descriptor_t *esscd = pipe->endpoint->esscd;
 	uint32_t mps = UGETW(ed->wMaxPacketSize);
 	uint8_t xfertype = UE_GET_XFERTYPE(ed->bmAttributes);
 	uint32_t maxb = 0;
@@ -1451,7 +1455,9 @@ xhci_pipe_maxburst(struct usbd_pipe *pip
 			maxb = UE_GET_TRANS(mps);
 		break;
 	case USB_SPEED_SUPER:
-		/*  XXX Read the companion descriptor */
+		if (esscd &&
+		    (xfertype == UE_ISOCHRONOUS || xfertype == UE_INTERRUPT))
+			maxb = esscd->bMaxBurst;
 	default:
 		break;
 	}