Various transfer improvements/fixes.

Chain TRBs when submitting bulk or interrupt transfers with a length
bigger than the Maxium Packet Size of the endpoint.

Append a supplementary TRB if a zero length packet is required.

While here, set the flags of each TRB at once.  Even if this driver
implementation fills the first TRB of a chain last, be safe and make
sure the hardware wont miss any flag.

Note that with this change, DMA sync operations might not cover the
whole chain, just like for control transfers, if the ring is starting
over.

Previous version of this diff tested by Peter N. M. Hansteen, thanks!

1 files changed, 75 insertions, 29 deletions

diff --git a/sys/dev/usb/xhci.c b/sys/dev/usb/xhci.c
index 25bb6f191ae..118a5770b56 100644
--- a/sys/dev/usb/xhci.c
+++ b/sys/dev/usb/xhci.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: xhci.c,v 1.48 2014/12/21 11:20:24 mpi Exp $ */
+/* $OpenBSD: xhci.c,v 1.49 2014/12/21 11:46:53 mpi Exp $ */
 
 /*
  * Copyright (c) 2014 Martin Pieuchot
@@ -2316,7 +2316,7 @@ xhci_device_ctrl_start(struct usbd_xfer *xfer)
 	struct xhci_softc *sc = (struct xhci_softc *)xfer->device->bus;
 	struct xhci_pipe *xp = (struct xhci_pipe *)xfer->pipe;
 	struct xhci_trb *trb0, *trb;
-	uint32_t len = UGETW(xfer->request.wLength);
+	uint32_t flags, len = UGETW(xfer->request.wLength);
 	uint8_t toggle0, toggle;
 	int s;
 
@@ -2334,39 +2334,42 @@ xhci_device_ctrl_start(struct usbd_xfer *xfer)
 	/* Data TRB */
 	if (len != 0) {
 		trb = xhci_xfer_get_trb(sc, xfer, &toggle, 0);
+
+		flags = XHCI_TRB_TYPE_DATA | toggle;
+		if (usbd_xfer_isread(xfer))
+			flags |= XHCI_TRB_DIR_IN | XHCI_TRB_ISP;
+
 		trb->trb_paddr = htole64(DMAADDR(&xfer->dmabuf, 0));
 		trb->trb_status = htole32(
 		    XHCI_TRB_INTR(0) | XHCI_TRB_TDREM(1) | XHCI_TRB_LEN(len)
 		);
-		trb->trb_flags = htole32(XHCI_TRB_TYPE_DATA | toggle);
-
-		if (usbd_xfer_isread(xfer))
-			trb->trb_flags |= htole32(XHCI_TRB_DIR_IN|XHCI_TRB_ISP);
+		trb->trb_flags = htole32(flags);
 
 	}
 
 	/* Status TRB */
 	trb = xhci_xfer_get_trb(sc, xfer, &toggle, 1);
-	trb->trb_paddr = 0;
-	trb->trb_status = htole32(XHCI_TRB_INTR(0));
-	trb->trb_flags = htole32(XHCI_TRB_TYPE_STATUS | XHCI_TRB_IOC | toggle);
 
+	flags = XHCI_TRB_TYPE_STATUS | XHCI_TRB_IOC | toggle;
 	if (len == 0 || !usbd_xfer_isread(xfer))
-		trb->trb_flags |= htole32(XHCI_TRB_DIR_IN);
+		flags |= XHCI_TRB_DIR_IN;
 
-	/* Setup TRB */
-	trb0->trb_paddr = (uint64_t)*((uint64_t *)&xfer->request);
-	trb0->trb_status = htole32(XHCI_TRB_INTR(0) | XHCI_TRB_LEN(8));
-	trb0->trb_flags = htole32(XHCI_TRB_TYPE_SETUP | XHCI_TRB_IDT);
+	trb->trb_paddr = 0;
+	trb->trb_status = htole32(XHCI_TRB_INTR(0));
+	trb->trb_flags = htole32(flags);
 
+	/* Setup TRB */
+	flags = XHCI_TRB_TYPE_SETUP | XHCI_TRB_IDT | toggle0;
 	if (len != 0) {
 		if (usbd_xfer_isread(xfer))
-			trb0->trb_flags |= htole32(XHCI_TRB_TRT_IN);
+			flags |= XHCI_TRB_TRT_IN;
 		else
-			trb0->trb_flags |= htole32(XHCI_TRB_TRT_OUT);
+			flags |= XHCI_TRB_TRT_OUT;
 	}
 
-	trb0->trb_flags |= htole32(toggle0);
+	trb0->trb_paddr = (uint64_t)*((uint64_t *)&xfer->request);
+	trb0->trb_status = htole32(XHCI_TRB_INTR(0) | XHCI_TRB_LEN(8));
+	trb0->trb_flags = htole32(flags);
 
 	bus_dmamap_sync(xp->ring.dma.tag, xp->ring.dma.map,
 	    TRBOFF(xp->ring, trb0), 3 * sizeof(struct xhci_trb),
@@ -2412,30 +2415,73 @@ xhci_device_generic_start(struct usbd_xfer *xfer)
 {
 	struct xhci_softc *sc = (struct xhci_softc *)xfer->device->bus;
 	struct xhci_pipe *xp = (struct xhci_pipe *)xfer->pipe;
-	struct xhci_trb *trb;
-	uint8_t toggle;
-	int s;
+	struct xhci_trb *trb0, *trb;
+	uint32_t len, remain, flags;
+	uint32_t len0, mps;
+	uint64_t paddr;
+	uint8_t toggle0, toggle;
+	int s, i, ntrb;
 
 	KASSERT(!(xfer->rqflags & URQ_REQUEST));
 
 	if (sc->sc_bus.dying || xp->halted)
 		return (USBD_IOERROR);
 
-	if (xp->free_trbs < 1)
+	/* How many TRBs do we need for this transfer? */
+	mps = UGETW(xfer->pipe->endpoint->edesc->wMaxPacketSize);
+	ntrb = (xfer->length + mps - 1) / mps;
+
+	/* If we need to append a zero length packet, we need one more. */
+	if ((xfer->flags & USBD_FORCE_SHORT_XFER || xfer->length == 0) &&
+	    (xfer->length % mps == 0))
+		ntrb++;
+
+	if (xp->free_trbs < ntrb)
 		return (USBD_NOMEM);
 
-	trb = xhci_xfer_get_trb(sc, xfer, &toggle, 1);
-	trb->trb_paddr = htole64(DMAADDR(&xfer->dmabuf, 0));
-	trb->trb_status = htole32(
-	    XHCI_TRB_INTR(0) | XHCI_TRB_TDREM(1) | XHCI_TRB_LEN(xfer->length)
-	);
-	trb->trb_flags = htole32(XHCI_TRB_TYPE_NORMAL | XHCI_TRB_IOC | toggle);
+	/* We'll do the first TRB once we're finished with the chain. */
+	trb0 = xhci_xfer_get_trb(sc, xfer, &toggle0, (ntrb == 1));
+	len0 = min(xfer->length, mps);
+
+	remain = xfer->length - len0;
+	paddr = DMAADDR(&xfer->dmabuf, 0) + len0;
+	len = min(remain, mps);
 
+	/* Chain more TRBs if needed. */
+	for (i = ntrb - 1; i > 0; i--) {
+		/* Next (or Last) TRB. */
+		trb = xhci_xfer_get_trb(sc, xfer, &toggle, (i == 1));
+		flags = XHCI_TRB_TYPE_NORMAL | toggle;
+		if (usbd_xfer_isread(xfer))
+			flags |= XHCI_TRB_ISP;
+		flags |= (i == 1) ? XHCI_TRB_IOC : XHCI_TRB_CHAIN;
+
+		trb->trb_paddr = htole64(paddr);
+		trb->trb_status = htole32(
+		    XHCI_TRB_INTR(0) | XHCI_TRB_TDREM(i) |
+		    XHCI_TRB_LEN(len)
+		);
+		trb->trb_flags = htole32(flags);
+
+		remain -= len;
+		paddr += len;
+		len = min(remain, mps);
+	}
+
+	/* First TRB. */
+	flags = XHCI_TRB_TYPE_NORMAL | toggle0;
 	if (usbd_xfer_isread(xfer))
-		trb->trb_flags |= htole32(XHCI_TRB_ISP);
+		flags |= XHCI_TRB_ISP;
+	flags |= (ntrb == 1) ? XHCI_TRB_IOC : XHCI_TRB_CHAIN;
+
+	trb0->trb_paddr = htole64(DMAADDR(&xfer->dmabuf, 0));
+	trb0->trb_status = htole32(
+	    XHCI_TRB_INTR(0) | XHCI_TRB_TDREM(ntrb) | XHCI_TRB_LEN(len0)
+ 	);
+	trb0->trb_flags = htole32(flags);
 
 	bus_dmamap_sync(xp->ring.dma.tag, xp->ring.dma.map,
-	    TRBOFF(xp->ring, trb), sizeof(struct xhci_trb),
+	    TRBOFF(xp->ring, trb0), sizeof(struct xhci_trb) * ntrb,
 	    BUS_DMASYNC_PREWRITE);
 
 	s = splusb();