musb-new: port of Linux musb driver

Existing U-Boot musb driver has no support for the new gadget framework
and also seems to have other limitations. As gadget framework is ported
from Linux it seems pretty natural to port musb gadget driver as well.

This driver supports both host and peripheral modes.

This is not a replacement for current musb driver (at least now) as
there are still some consumers of the old UDC interface.

No DMA operation support included, CONFIG_MUSB_PIO_ONLY should be
defined.

Virtual root hub device is not implemented.

Known problems: with no devices connected usb_lowlevel_start() fails.

Signed-off-by: Ilya Yanok <ilya.yanok@cogentembedded.com>

1 files changed, 2400 insertions, 0 deletions

diff --git a/drivers/usb/musb-new/musb_host.c b/drivers/usb/musb-new/musb_host.c
new file mode 100644
index 0000000000..9a2cf59d92
--- /dev/null
+++ b/drivers/usb/musb-new/musb_host.c
@@ -0,0 +1,2400 @@
+/*
+ * MUSB OTG driver host support
+ *
+ * Copyright 2005 Mentor Graphics Corporation
+ * Copyright (C) 2005-2006 by Texas Instruments
+ * Copyright (C) 2006-2007 Nokia Corporation
+ * Copyright (C) 2008-2009 MontaVista Software, Inc. <source@mvista.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#define __UBOOT__
+#ifndef __UBOOT__
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/dma-mapping.h>
+#else
+#include <common.h>
+#include <usb.h>
+#include "linux-compat.h"
+#include "usb-compat.h"
+#endif
+
+#include "musb_core.h"
+#include "musb_host.h"
+
+
+/* MUSB HOST status 22-mar-2006
+ *
+ * - There's still lots of partial code duplication for fault paths, so
+ *   they aren't handled as consistently as they need to be.
+ *
+ * - PIO mostly behaved when last tested.
+ *     + including ep0, with all usbtest cases 9, 10
+ *     + usbtest 14 (ep0out) doesn't seem to run at all
+ *     + double buffered OUT/TX endpoints saw stalls(!) with certain usbtest
+ *       configurations, but otherwise double buffering passes basic tests.
+ *     + for 2.6.N, for N > ~10, needs API changes for hcd framework.
+ *
+ * - DMA (CPPI) ... partially behaves, not currently recommended
+ *     + about 1/15 the speed of typical EHCI implementations (PCI)
+ *     + RX, all too often reqpkt seems to misbehave after tx
+ *     + TX, no known issues (other than evident silicon issue)
+ *
+ * - DMA (Mentor/OMAP) ...has at least toggle update problems
+ *
+ * - [23-feb-2009] minimal traffic scheduling to avoid bulk RX packet
+ *   starvation ... nothing yet for TX, interrupt, or bulk.
+ *
+ * - Not tested with HNP, but some SRP paths seem to behave.
+ *
+ * NOTE 24-August-2006:
+ *
+ * - Bulk traffic finally uses both sides of hardware ep1, freeing up an
+ *   extra endpoint for periodic use enabling hub + keybd + mouse.  That
+ *   mostly works, except that with "usbnet" it's easy to trigger cases
+ *   with "ping" where RX loses.  (a) ping to davinci, even "ping -f",
+ *   fine; but (b) ping _from_ davinci, even "ping -c 1", ICMP RX loses
+ *   although ARP RX wins.  (That test was done with a full speed link.)
+ */
+
+
+/*
+ * NOTE on endpoint usage:
+ *
+ * CONTROL transfers all go through ep0.  BULK ones go through dedicated IN
+ * and OUT endpoints ... hardware is dedicated for those "async" queue(s).
+ * (Yes, bulk _could_ use more of the endpoints than that, and would even
+ * benefit from it.)
+ *
+ * INTERUPPT and ISOCHRONOUS transfers are scheduled to the other endpoints.
+ * So far that scheduling is both dumb and optimistic:  the endpoint will be
+ * "claimed" until its software queue is no longer refilled.  No multiplexing
+ * of transfers between endpoints, or anything clever.
+ */
+
+
+static void musb_ep_program(struct musb *musb, u8 epnum,
+			struct urb *urb, int is_out,
+			u8 *buf, u32 offset, u32 len);
+
+/*
+ * Clear TX fifo. Needed to avoid BABBLE errors.
+ */
+static void musb_h_tx_flush_fifo(struct musb_hw_ep *ep)
+{
+	struct musb	*musb = ep->musb;
+	void __iomem	*epio = ep->regs;
+	u16		csr;
+	u16		lastcsr = 0;
+	int		retries = 1000;
+
+	csr = musb_readw(epio, MUSB_TXCSR);
+	while (csr & MUSB_TXCSR_FIFONOTEMPTY) {
+		if (csr != lastcsr)
+			dev_dbg(musb->controller, "Host TX FIFONOTEMPTY csr: %02x\n", csr);
+		lastcsr = csr;
+		csr |= MUSB_TXCSR_FLUSHFIFO;
+		musb_writew(epio, MUSB_TXCSR, csr);
+		csr = musb_readw(epio, MUSB_TXCSR);
+		if (WARN(retries-- < 1,
+				"Could not flush host TX%d fifo: csr: %04x\n",
+				ep->epnum, csr))
+			return;
+		mdelay(1);
+	}
+}
+
+static void musb_h_ep0_flush_fifo(struct musb_hw_ep *ep)
+{
+	void __iomem	*epio = ep->regs;
+	u16		csr;
+	int		retries = 5;
+
+	/* scrub any data left in the fifo */
+	do {
+		csr = musb_readw(epio, MUSB_TXCSR);
+		if (!(csr & (MUSB_CSR0_TXPKTRDY | MUSB_CSR0_RXPKTRDY)))
+			break;
+		musb_writew(epio, MUSB_TXCSR, MUSB_CSR0_FLUSHFIFO);
+		csr = musb_readw(epio, MUSB_TXCSR);
+		udelay(10);
+	} while (--retries);
+
+	WARN(!retries, "Could not flush host TX%d fifo: csr: %04x\n",
+			ep->epnum, csr);
+
+	/* and reset for the next transfer */
+	musb_writew(epio, MUSB_TXCSR, 0);
+}
+
+/*
+ * Start transmit. Caller is responsible for locking shared resources.
+ * musb must be locked.
+ */
+static inline void musb_h_tx_start(struct musb_hw_ep *ep)
+{
+	u16	txcsr;
+
+	/* NOTE: no locks here; caller should lock and select EP */
+	if (ep->epnum) {
+		txcsr = musb_readw(ep->regs, MUSB_TXCSR);
+		txcsr |= MUSB_TXCSR_TXPKTRDY | MUSB_TXCSR_H_WZC_BITS;
+		musb_writew(ep->regs, MUSB_TXCSR, txcsr);
+	} else {
+		txcsr = MUSB_CSR0_H_SETUPPKT | MUSB_CSR0_TXPKTRDY;
+		musb_writew(ep->regs, MUSB_CSR0, txcsr);
+	}
+
+}
+
+static inline void musb_h_tx_dma_start(struct musb_hw_ep *ep)
+{
+	u16	txcsr;
+
+	/* NOTE: no locks here; caller should lock and select EP */
+	txcsr = musb_readw(ep->regs, MUSB_TXCSR);
+	txcsr |= MUSB_TXCSR_DMAENAB | MUSB_TXCSR_H_WZC_BITS;
+	if (is_cppi_enabled())
+		txcsr |= MUSB_TXCSR_DMAMODE;
+	musb_writew(ep->regs, MUSB_TXCSR, txcsr);
+}
+
+static void musb_ep_set_qh(struct musb_hw_ep *ep, int is_in, struct musb_qh *qh)
+{
+	if (is_in != 0 || ep->is_shared_fifo)
+		ep->in_qh  = qh;
+	if (is_in == 0 || ep->is_shared_fifo)
+		ep->out_qh = qh;
+}
+
+static struct musb_qh *musb_ep_get_qh(struct musb_hw_ep *ep, int is_in)
+{
+	return is_in ? ep->in_qh : ep->out_qh;
+}
+
+/*
+ * Start the URB at the front of an endpoint's queue
+ * end must be claimed from the caller.
+ *
+ * Context: controller locked, irqs blocked
+ */
+static void
+musb_start_urb(struct musb *musb, int is_in, struct musb_qh *qh)
+{
+	u16			frame;
+	u32			len;
+	void __iomem		*mbase =  musb->mregs;
+	struct urb		*urb = next_urb(qh);
+	void			*buf = urb->transfer_buffer;
+	u32			offset = 0;
+	struct musb_hw_ep	*hw_ep = qh->hw_ep;
+	unsigned		pipe = urb->pipe;
+	u8			address = usb_pipedevice(pipe);
+	int			epnum = hw_ep->epnum;
+
+	/* initialize software qh state */
+	qh->offset = 0;
+	qh->segsize = 0;
+
+	/* gather right source of data */
+	switch (qh->type) {
+	case USB_ENDPOINT_XFER_CONTROL:
+		/* control transfers always start with SETUP */
+		is_in = 0;
+		musb->ep0_stage = MUSB_EP0_START;
+		buf = urb->setup_packet;
+		len = 8;
+		break;
+#ifndef __UBOOT__
+	case USB_ENDPOINT_XFER_ISOC:
+		qh->iso_idx = 0;
+		qh->frame = 0;
+		offset = urb->iso_frame_desc[0].offset;
+		len = urb->iso_frame_desc[0].length;
+		break;
+#endif
+	default:		/* bulk, interrupt */
+		/* actual_length may be nonzero on retry paths */
+		buf = urb->transfer_buffer + urb->actual_length;
+		len = urb->transfer_buffer_length - urb->actual_length;
+	}
+
+	dev_dbg(musb->controller, "qh %p urb %p dev%d ep%d%s%s, hw_ep %d, %p/%d\n",
+			qh, urb, address, qh->epnum,
+			is_in ? "in" : "out",
+			({char *s; switch (qh->type) {
+			case USB_ENDPOINT_XFER_CONTROL:	s = ""; break;
+			case USB_ENDPOINT_XFER_BULK:	s = "-bulk"; break;
+#ifndef __UBOOT__
+			case USB_ENDPOINT_XFER_ISOC:	s = "-iso"; break;
+#endif
+			default:			s = "-intr"; break;
+			}; s; }),
+			epnum, buf + offset, len);
+
+	/* Configure endpoint */
+	musb_ep_set_qh(hw_ep, is_in, qh);
+	musb_ep_program(musb, epnum, urb, !is_in, buf, offset, len);
+
+	/* transmit may have more work: start it when it is time */
+	if (is_in)
+		return;
+
+	/* determine if the time is right for a periodic transfer */
+	switch (qh->type) {
+#ifndef __UBOOT__
+	case USB_ENDPOINT_XFER_ISOC:
+#endif
+	case USB_ENDPOINT_XFER_INT:
+		dev_dbg(musb->controller, "check whether there's still time for periodic Tx\n");
+		frame = musb_readw(mbase, MUSB_FRAME);
+		/* FIXME this doesn't implement that scheduling policy ...
+		 * or handle framecounter wrapping
+		 */
+#ifndef __UBOOT__
+		if ((urb->transfer_flags & URB_ISO_ASAP)
+				|| (frame >= urb->start_frame)) {
+			/* REVISIT the SOF irq handler shouldn't duplicate
+			 * this code; and we don't init urb->start_frame...
+			 */
+			qh->frame = 0;
+			goto start;
+		} else {
+#endif
+			qh->frame = urb->start_frame;
+			/* enable SOF interrupt so we can count down */
+			dev_dbg(musb->controller, "SOF for %d\n", epnum);
+#if 1 /* ifndef	CONFIG_ARCH_DAVINCI */
+			musb_writeb(mbase, MUSB_INTRUSBE, 0xff);
+#endif
+#ifndef __UBOOT__
+		}
+#endif
+		break;
+	default:
+start:
+		dev_dbg(musb->controller, "Start TX%d %s\n", epnum,
+			hw_ep->tx_channel ? "dma" : "pio");
+
+		if (!hw_ep->tx_channel)
+			musb_h_tx_start(hw_ep);
+		else if (is_cppi_enabled() || tusb_dma_omap())
+			musb_h_tx_dma_start(hw_ep);
+	}
+}
+
+/* Context: caller owns controller lock, IRQs are blocked */
+static void musb_giveback(struct musb *musb, struct urb *urb, int status)
+__releases(musb->lock)
+__acquires(musb->lock)
+{
+	dev_dbg(musb->controller,
+			"complete %p %pF (%d), dev%d ep%d%s, %d/%d\n",
+			urb, urb->complete, status,
+			usb_pipedevice(urb->pipe),
+			usb_pipeendpoint(urb->pipe),
+			usb_pipein(urb->pipe) ? "in" : "out",
+			urb->actual_length, urb->transfer_buffer_length
+			);
+
+	usb_hcd_unlink_urb_from_ep(musb_to_hcd(musb), urb);
+	spin_unlock(&musb->lock);
+	usb_hcd_giveback_urb(musb_to_hcd(musb), urb, status);
+	spin_lock(&musb->lock);
+}
+
+/* For bulk/interrupt endpoints only */
+static inline void musb_save_toggle(struct musb_qh *qh, int is_in,
+				    struct urb *urb)
+{
+	void __iomem		*epio = qh->hw_ep->regs;
+	u16			csr;
+
+	/*
+	 * FIXME: the current Mentor DMA code seems to have
+	 * problems getting toggle correct.
+	 */
+
+	if (is_in)
+		csr = musb_readw(epio, MUSB_RXCSR) & MUSB_RXCSR_H_DATATOGGLE;
+	else
+		csr = musb_readw(epio, MUSB_TXCSR) & MUSB_TXCSR_H_DATATOGGLE;
+
+	usb_settoggle(urb->dev, qh->epnum, !is_in, csr ? 1 : 0);
+}
+
+/*
+ * Advance this hardware endpoint's queue, completing the specified URB and
+ * advancing to either the next URB queued to that qh, or else invalidating
+ * that qh and advancing to the next qh scheduled after the current one.
+ *
+ * Context: caller owns controller lock, IRQs are blocked
+ */
+static void musb_advance_schedule(struct musb *musb, struct urb *urb,
+				  struct musb_hw_ep *hw_ep, int is_in)
+{
+	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, is_in);
+	struct musb_hw_ep	*ep = qh->hw_ep;
+	int			ready = qh->is_ready;
+	int			status;
+
+	status = (urb->status == -EINPROGRESS) ? 0 : urb->status;
+
+	/* save toggle eagerly, for paranoia */
+	switch (qh->type) {
+	case USB_ENDPOINT_XFER_BULK:
+	case USB_ENDPOINT_XFER_INT:
+		musb_save_toggle(qh, is_in, urb);
+		break;
+#ifndef __UBOOT__
+	case USB_ENDPOINT_XFER_ISOC:
+		if (status == 0 && urb->error_count)
+			status = -EXDEV;
+		break;
+#endif
+	}
+
+	qh->is_ready = 0;
+	musb_giveback(musb, urb, status);
+	qh->is_ready = ready;
+
+	/* reclaim resources (and bandwidth) ASAP; deschedule it, and
+	 * invalidate qh as soon as list_empty(&hep->urb_list)
+	 */
+	if (list_empty(&qh->hep->urb_list)) {
+		struct list_head	*head;
+		struct dma_controller	*dma = musb->dma_controller;
+
+		if (is_in) {
+			ep->rx_reinit = 1;
+			if (ep->rx_channel) {
+				dma->channel_release(ep->rx_channel);
+				ep->rx_channel = NULL;
+			}
+		} else {
+			ep->tx_reinit = 1;
+			if (ep->tx_channel) {
+				dma->channel_release(ep->tx_channel);
+				ep->tx_channel = NULL;
+			}
+		}
+
+		/* Clobber old pointers to this qh */
+		musb_ep_set_qh(ep, is_in, NULL);
+		qh->hep->hcpriv = NULL;
+
+		switch (qh->type) {
+
+		case USB_ENDPOINT_XFER_CONTROL:
+		case USB_ENDPOINT_XFER_BULK:
+			/* fifo policy for these lists, except that NAKing
+			 * should rotate a qh to the end (for fairness).
+			 */
+			if (qh->mux == 1) {
+				head = qh->ring.prev;
+				list_del(&qh->ring);
+				kfree(qh);
+				qh = first_qh(head);
+				break;
+			}
+
+		case USB_ENDPOINT_XFER_ISOC:
+		case USB_ENDPOINT_XFER_INT:
+			/* this is where periodic bandwidth should be
+			 * de-allocated if it's tracked and allocated;
+			 * and where we'd update the schedule tree...
+			 */
+			kfree(qh);
+			qh = NULL;
+			break;
+		}
+	}
+
+	if (qh != NULL && qh->is_ready) {
+		dev_dbg(musb->controller, "... next ep%d %cX urb %p\n",
+		    hw_ep->epnum, is_in ? 'R' : 'T', next_urb(qh));
+		musb_start_urb(musb, is_in, qh);
+	}
+}
+
+static u16 musb_h_flush_rxfifo(struct musb_hw_ep *hw_ep, u16 csr)
+{
+	/* we don't want fifo to fill itself again;
+	 * ignore dma (various models),
+	 * leave toggle alone (may not have been saved yet)
+	 */
+	csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_RXPKTRDY;
+	csr &= ~(MUSB_RXCSR_H_REQPKT
+		| MUSB_RXCSR_H_AUTOREQ
+		| MUSB_RXCSR_AUTOCLEAR);
+
+	/* write 2x to allow double buffering */
+	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
+	musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
+
+	/* flush writebuffer */
+	return musb_readw(hw_ep->regs, MUSB_RXCSR);
+}
+
+/*
+ * PIO RX for a packet (or part of it).
+ */
+static bool
+musb_host_packet_rx(struct musb *musb, struct urb *urb, u8 epnum, u8 iso_err)
+{
+	u16			rx_count;
+	u8			*buf;
+	u16			csr;
+	bool			done = false;
+	u32			length;
+	int			do_flush = 0;
+	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
+	void __iomem		*epio = hw_ep->regs;
+	struct musb_qh		*qh = hw_ep->in_qh;
+	int			pipe = urb->pipe;
+	void			*buffer = urb->transfer_buffer;
+
+	/* musb_ep_select(mbase, epnum); */
+	rx_count = musb_readw(epio, MUSB_RXCOUNT);
+	dev_dbg(musb->controller, "RX%d count %d, buffer %p len %d/%d\n", epnum, rx_count,
+			urb->transfer_buffer, qh->offset,
+			urb->transfer_buffer_length);
+
+	/* unload FIFO */
+#ifndef __UBOOT__
+	if (usb_pipeisoc(pipe)) {
+		int					status = 0;
+		struct usb_iso_packet_descriptor	*d;
+
+		if (iso_err) {
+			status = -EILSEQ;
+			urb->error_count++;
+		}
+
+		d = urb->iso_frame_desc + qh->iso_idx;
+		buf = buffer + d->offset;
+		length = d->length;
+		if (rx_count > length) {
+			if (status == 0) {
+				status = -EOVERFLOW;
+				urb->error_count++;
+			}
+			dev_dbg(musb->controller, "** OVERFLOW %d into %d\n", rx_count, length);
+			do_flush = 1;
+		} else
+			length = rx_count;
+		urb->actual_length += length;
+		d->actual_length = length;
+
+		d->status = status;
+
+		/* see if we are done */
+		done = (++qh->iso_idx >= urb->number_of_packets);
+	} else {
+#endif
+		/* non-isoch */
+		buf = buffer + qh->offset;
+		length = urb->transfer_buffer_length - qh->offset;
+		if (rx_count > length) {
+			if (urb->status == -EINPROGRESS)
+				urb->status = -EOVERFLOW;
+			dev_dbg(musb->controller, "** OVERFLOW %d into %d\n", rx_count, length);
+			do_flush = 1;
+		} else
+			length = rx_count;
+		urb->actual_length += length;
+		qh->offset += length;
+
+		/* see if we are done */
+		done = (urb->actual_length == urb->transfer_buffer_length)
+			|| (rx_count < qh->maxpacket)
+			|| (urb->status != -EINPROGRESS);
+		if (done
+				&& (urb->status == -EINPROGRESS)
+				&& (urb->transfer_flags & URB_SHORT_NOT_OK)
+				&& (urb->actual_length
+					< urb->transfer_buffer_length))
+			urb->status = -EREMOTEIO;
+#ifndef __UBOOT__
+	}
+#endif
+
+	musb_read_fifo(hw_ep, length, buf);
+
+	csr = musb_readw(epio, MUSB_RXCSR);
+	csr |= MUSB_RXCSR_H_WZC_BITS;
+	if (unlikely(do_flush))
+		musb_h_flush_rxfifo(hw_ep, csr);
+	else {
+		/* REVISIT this assumes AUTOCLEAR is never set */
+		csr &= ~(MUSB_RXCSR_RXPKTRDY | MUSB_RXCSR_H_REQPKT);
+		if (!done)
+			csr |= MUSB_RXCSR_H_REQPKT;
+		musb_writew(epio, MUSB_RXCSR, csr);
+	}
+
+	return done;
+}
+
+/* we don't always need to reinit a given side of an endpoint...
+ * when we do, use tx/rx reinit routine and then construct a new CSR
+ * to address data toggle, NYET, and DMA or PIO.
+ *
+ * it's possible that driver bugs (especially for DMA) or aborting a
+ * transfer might have left the endpoint busier than it should be.
+ * the busy/not-empty tests are basically paranoia.
+ */
+static void
+musb_rx_reinit(struct musb *musb, struct musb_qh *qh, struct musb_hw_ep *ep)
+{
+	u16	csr;
+
+	/* NOTE:  we know the "rx" fifo reinit never triggers for ep0.
+	 * That always uses tx_reinit since ep0 repurposes TX register
+	 * offsets; the initial SETUP packet is also a kind of OUT.
+	 */
+
+	/* if programmed for Tx, put it in RX mode */
+	if (ep->is_shared_fifo) {
+		csr = musb_readw(ep->regs, MUSB_TXCSR);
+		if (csr & MUSB_TXCSR_MODE) {
+			musb_h_tx_flush_fifo(ep);
+			csr = musb_readw(ep->regs, MUSB_TXCSR);
+			musb_writew(ep->regs, MUSB_TXCSR,
+				    csr | MUSB_TXCSR_FRCDATATOG);
+		}
+
+		/*
+		 * Clear the MODE bit (and everything else) to enable Rx.
+		 * NOTE: we mustn't clear the DMAMODE bit before DMAENAB.
+		 */
+		if (csr & MUSB_TXCSR_DMAMODE)
+			musb_writew(ep->regs, MUSB_TXCSR, MUSB_TXCSR_DMAMODE);
+		musb_writew(ep->regs, MUSB_TXCSR, 0);
+
+	/* scrub all previous state, clearing toggle */
+	} else {
+		csr = musb_readw(ep->regs, MUSB_RXCSR);
+		if (csr & MUSB_RXCSR_RXPKTRDY)
+			WARNING("rx%d, packet/%d ready?\n", ep->epnum,
+				musb_readw(ep->regs, MUSB_RXCOUNT));
+
+		musb_h_flush_rxfifo(ep, MUSB_RXCSR_CLRDATATOG);
+	}
+
+	/* target addr and (for multipoint) hub addr/port */
+	if (musb->is_multipoint) {
+		musb_write_rxfunaddr(ep->target_regs, qh->addr_reg);
+		musb_write_rxhubaddr(ep->target_regs, qh->h_addr_reg);
+		musb_write_rxhubport(ep->target_regs, qh->h_port_reg);
+
+	} else
+		musb_writeb(musb->mregs, MUSB_FADDR, qh->addr_reg);
+
+	/* protocol/endpoint, interval/NAKlimit, i/o size */
+	musb_writeb(ep->regs, MUSB_RXTYPE, qh->type_reg);
+	musb_writeb(ep->regs, MUSB_RXINTERVAL, qh->intv_reg);
+	/* NOTE: bulk combining rewrites high bits of maxpacket */
+	/* Set RXMAXP with the FIFO size of the endpoint
+	 * to disable double buffer mode.
+	 */
+	if (musb->double_buffer_not_ok)
+		musb_writew(ep->regs, MUSB_RXMAXP, ep->max_packet_sz_rx);
+	else
+		musb_writew(ep->regs, MUSB_RXMAXP,
+				qh->maxpacket | ((qh->hb_mult - 1) << 11));
+
+	ep->rx_reinit = 0;
+}
+
+static bool musb_tx_dma_program(struct dma_controller *dma,
+		struct musb_hw_ep *hw_ep, struct musb_qh *qh,
+		struct urb *urb, u32 offset, u32 length)
+{
+	struct dma_channel	*channel = hw_ep->tx_channel;
+	void __iomem		*epio = hw_ep->regs;
+	u16			pkt_size = qh->maxpacket;
+	u16			csr;
+	u8			mode;
+
+#ifdef	CONFIG_USB_INVENTRA_DMA
+	if (length > channel->max_len)
+		length = channel->max_len;
+
+	csr = musb_readw(epio, MUSB_TXCSR);
+	if (length > pkt_size) {
+		mode = 1;
+		csr |= MUSB_TXCSR_DMAMODE | MUSB_TXCSR_DMAENAB;
+		/* autoset shouldn't be set in high bandwidth */
+		if (qh->hb_mult == 1)
+			csr |= MUSB_TXCSR_AUTOSET;
+	} else {
+		mode = 0;
+		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAMODE);
+		csr |= MUSB_TXCSR_DMAENAB; /* against programmer's guide */
+	}
+	channel->desired_mode = mode;
+	musb_writew(epio, MUSB_TXCSR, csr);
+#else
+	if (!is_cppi_enabled() && !tusb_dma_omap())
+		return false;
+
+	channel->actual_len = 0;
+
+	/*
+	 * TX uses "RNDIS" mode automatically but needs help
+	 * to identify the zero-length-final-packet case.
+	 */
+	mode = (urb->transfer_flags & URB_ZERO_PACKET) ? 1 : 0;
+#endif
+
+	qh->segsize = length;
+
+	/*
+	 * Ensure the data reaches to main memory before starting
+	 * DMA transfer
+	 */
+	wmb();
+
+	if (!dma->channel_program(channel, pkt_size, mode,
+			urb->transfer_dma + offset, length)) {
+		dma->channel_release(channel);
+		hw_ep->tx_channel = NULL;
+
+		csr = musb_readw(epio, MUSB_TXCSR);
+		csr &= ~(MUSB_TXCSR_AUTOSET | MUSB_TXCSR_DMAENAB);
+		musb_writew(epio, MUSB_TXCSR, csr | MUSB_TXCSR_H_WZC_BITS);
+		return false;
+	}
+	return true;
+}
+
+/*
+ * Program an HDRC endpoint as per the given URB
+ * Context: irqs blocked, controller lock held
+ */
+static void musb_ep_program(struct musb *musb, u8 epnum,
+			struct urb *urb, int is_out,
+			u8 *buf, u32 offset, u32 len)
+{
+	struct dma_controller	*dma_controller;
+	struct dma_channel	*dma_channel;
+	u8			dma_ok;
+	void __iomem		*mbase = musb->mregs;
+	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
+	void __iomem		*epio = hw_ep->regs;
+	struct musb_qh		*qh = musb_ep_get_qh(hw_ep, !is_out);
+	u16			packet_sz = qh->maxpacket;
+
+	dev_dbg(musb->controller, "%s hw%d urb %p spd%d dev%d ep%d%s "
+				"h_addr%02x h_port%02x bytes %d\n",
+			is_out ? "-->" : "<--",
+			epnum, urb, urb->dev->speed,
+			qh->addr_reg, qh->epnum, is_out ? "out" : "in",
+			qh->h_addr_reg, qh->h_port_reg,
+			len);
+
+	musb_ep_select(mbase, epnum);
+
+	/* candidate for DMA? */
+	dma_controller = musb->dma_controller;
+	if (is_dma_capable() && epnum && dma_controller) {
+		dma_channel = is_out ? hw_ep->tx_channel : hw_ep->rx_channel;
+		if (!dma_channel) {
+			dma_channel = dma_controller->channel_alloc(
+					dma_controller, hw_ep, is_out);
+			if (is_out)
+				hw_ep->tx_channel = dma_channel;
+			else
+				hw_ep->rx_channel = dma_channel;
+		}
+	} else
+		dma_channel = NULL;
+
+	/* make sure we clear DMAEnab, autoSet bits from previous run */
+
+	/* OUT/transmit/EP0 or IN/receive? */
+	if (is_out) {
+		u16	csr;
+		u16	int_txe;
+		u16	load_count;
+
+		csr = musb_readw(epio, MUSB_TXCSR);
+
+		/* disable interrupt in case we flush */
+		int_txe = musb_readw(mbase, MUSB_INTRTXE);
+		musb_writew(mbase, MUSB_INTRTXE, int_txe & ~(1 << epnum));
+
+		/* general endpoint setup */
+		if (epnum) {
+			/* flush all old state, set default */
+			musb_h_tx_flush_fifo(hw_ep);
+
+			/*
+			 * We must not clear the DMAMODE bit before or in
+			 * the same cycle with the DMAENAB bit, so we clear
+			 * the latter first...
+			 */
+			csr &= ~(MUSB_TXCSR_H_NAKTIMEOUT
+					| MUSB_TXCSR_AUTOSET
+					| MUSB_TXCSR_DMAENAB
+					| MUSB_TXCSR_FRCDATATOG
+					| MUSB_TXCSR_H_RXSTALL
+					| MUSB_TXCSR_H_ERROR
+					| MUSB_TXCSR_TXPKTRDY
+					);
+			csr |= MUSB_TXCSR_MODE;
+
+			if (usb_gettoggle(urb->dev, qh->epnum, 1))
+				csr |= MUSB_TXCSR_H_WR_DATATOGGLE
+					| MUSB_TXCSR_H_DATATOGGLE;
+			else
+				csr |= MUSB_TXCSR_CLRDATATOG;
+
+			musb_writew(epio, MUSB_TXCSR, csr);
+			/* REVISIT may need to clear FLUSHFIFO ... */
+			csr &= ~MUSB_TXCSR_DMAMODE;
+			musb_writew(epio, MUSB_TXCSR, csr);
+			csr = musb_readw(epio, MUSB_TXCSR);
+		} else {
+			/* endpoint 0: just flush */
+			musb_h_ep0_flush_fifo(hw_ep);
+		}
+
+		/* target addr and (for multipoint) hub addr/port */
+		if (musb->is_multipoint) {
+			musb_write_txfunaddr(mbase, epnum, qh->addr_reg);
+			musb_write_txhubaddr(mbase, epnum, qh->h_addr_reg);
+			musb_write_txhubport(mbase, epnum, qh->h_port_reg);
+/* FIXME if !epnum, do the same for RX ... */
+		} else
+			musb_writeb(mbase, MUSB_FADDR, qh->addr_reg);
+
+		/* protocol/endpoint/interval/NAKlimit */
+		if (epnum) {
+			musb_writeb(epio, MUSB_TXTYPE, qh->type_reg);
+			if (musb->double_buffer_not_ok)
+				musb_writew(epio, MUSB_TXMAXP,
+						hw_ep->max_packet_sz_tx);
+			else if (can_bulk_split(musb, qh->type))
+				musb_writew(epio, MUSB_TXMAXP, packet_sz
+					| ((hw_ep->max_packet_sz_tx /
+						packet_sz) - 1) << 11);
+			else
+				musb_writew(epio, MUSB_TXMAXP,
+						qh->maxpacket |
+						((qh->hb_mult - 1) << 11));
+			musb_writeb(epio, MUSB_TXINTERVAL, qh->intv_reg);
+		} else {
+			musb_writeb(epio, MUSB_NAKLIMIT0, qh->intv_reg);
+			if (musb->is_multipoint)
+				musb_writeb(epio, MUSB_TYPE0,
+						qh->type_reg);
+		}
+
+		if (can_bulk_split(musb, qh->type))
+			load_count = min((u32) hw_ep->max_packet_sz_tx,
+						len);
+		else
+			load_count = min((u32) packet_sz, len);
+
+		if (dma_channel && musb_tx_dma_program(dma_controller,
+					hw_ep, qh, urb, offset, len))
+			load_count = 0;
+
+		if (load_count) {
+			/* PIO to load FIFO */
+			qh->segsize = load_count;
+			musb_write_fifo(hw_ep, load_count, buf);
+		}
+
+		/* re-enable interrupt */
+		musb_writew(mbase, MUSB_INTRTXE, int_txe);
+
+	/* IN/receive */
+	} else {
+		u16	csr;
+
+		if (hw_ep->rx_reinit) {
+			musb_rx_reinit(musb, qh, hw_ep);
+
+			/* init new state: toggle and NYET, maybe DMA later */
+			if (usb_gettoggle(urb->dev, qh->epnum, 0))
+				csr = MUSB_RXCSR_H_WR_DATATOGGLE
+					| MUSB_RXCSR_H_DATATOGGLE;
+			else
+				csr = 0;
+			if (qh->type == USB_ENDPOINT_XFER_INT)
+				csr |= MUSB_RXCSR_DISNYET;
+
+		} else {
+			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
+
+			if (csr & (MUSB_RXCSR_RXPKTRDY
+					| MUSB_RXCSR_DMAENAB
+					| MUSB_RXCSR_H_REQPKT))
+				ERR("broken !rx_reinit, ep%d csr %04x\n",
+						hw_ep->epnum, csr);
+
+			/* scrub any stale state, leaving toggle alone */
+			csr &= MUSB_RXCSR_DISNYET;
+		}
+
+		/* kick things off */
+
+		if ((is_cppi_enabled() || tusb_dma_omap()) && dma_channel) {
+			/* Candidate for DMA */
+			dma_channel->actual_len = 0L;
+			qh->segsize = len;
+
+			/* AUTOREQ is in a DMA register */
+			musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
+			csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
+
+			/*
+			 * Unless caller treats short RX transfers as
+			 * errors, we dare not queue multiple transfers.
+			 */
+			dma_ok = dma_controller->channel_program(dma_channel,
+					packet_sz, !(urb->transfer_flags &
+						     URB_SHORT_NOT_OK),
+					urb->transfer_dma + offset,
+					qh->segsize);
+			if (!dma_ok) {
+				dma_controller->channel_release(dma_channel);
+				hw_ep->rx_channel = dma_channel = NULL;
+			} else
+				csr |= MUSB_RXCSR_DMAENAB;
+		}
+
+		csr |= MUSB_RXCSR_H_REQPKT;
+		dev_dbg(musb->controller, "RXCSR%d := %04x\n", epnum, csr);
+		musb_writew(hw_ep->regs, MUSB_RXCSR, csr);
+		csr = musb_readw(hw_ep->regs, MUSB_RXCSR);
+	}
+}
+
+
+/*
+ * Service the default endpoint (ep0) as host.
+ * Return true until it's time to start the status stage.
+ */
+static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
+{
+	bool			 more = false;
+	u8			*fifo_dest = NULL;
+	u16			fifo_count = 0;
+	struct musb_hw_ep	*hw_ep = musb->control_ep;
+	struct musb_qh		*qh = hw_ep->in_qh;
+	struct usb_ctrlrequest	*request;
+
+	switch (musb->ep0_stage) {
+	case MUSB_EP0_IN:
+		fifo_dest = urb->transfer_buffer + urb->actual_length;
+		fifo_count = min_t(size_t, len, urb->transfer_buffer_length -
+				   urb->actual_length);
+		if (fifo_count < len)
+			urb->status = -EOVERFLOW;
+
+		musb_read_fifo(hw_ep, fifo_count, fifo_dest);
+
+		urb->actual_length += fifo_count;
+		if (len < qh->maxpacket) {
+			/* always terminate on short read; it's
+			 * rarely reported as an error.
+			 */
+		} else if (urb->actual_length <
+				urb->transfer_buffer_length)
+			more = true;
+		break;
+	case MUSB_EP0_START:
+		request = (struct usb_ctrlrequest *) urb->setup_packet;
+
+		if (!request->wLength) {
+			dev_dbg(musb->controller, "start no-DATA\n");
+			break;
+		} else if (request->bRequestType & USB_DIR_IN) {
+			dev_dbg(musb->controller, "start IN-DATA\n");
+			musb->ep0_stage = MUSB_EP0_IN;
+			more = true;
+			break;
+		} else {
+			dev_dbg(musb->controller, "start OUT-DATA\n");
+			musb->ep0_stage = MUSB_EP0_OUT;
+			more = true;
+		}
+		/* FALLTHROUGH */
+	case MUSB_EP0_OUT:
+		fifo_count = min_t(size_t, qh->maxpacket,
+				   urb->transfer_buffer_length -
+				   urb->actual_length);
+		if (fifo_count) {
+			fifo_dest = (u8 *) (urb->transfer_buffer
+					+ urb->actual_length);
+			dev_dbg(musb->controller, "Sending %d byte%s to ep0 fifo %p\n",
+					fifo_count,
+					(fifo_count == 1) ? "" : "s",
+					fifo_dest);
+			musb_write_fifo(hw_ep, fifo_count, fifo_dest);
+
+			urb->actual_length += fifo_count;
+			more = true;
+		}
+		break;
+	default:
+		ERR("bogus ep0 stage %d\n", musb->ep0_stage);
+		break;
+	}
+
+	return more;
+}
+
+/*
+ * Handle default endpoint interrupt as host. Only called in IRQ time
+ * from musb_interrupt().
+ *
+ * called with controller irqlocked
+ */
+irqreturn_t musb_h_ep0_irq(struct musb *musb)
+{
+	struct urb		*urb;
+	u16			csr, len;
+	int			status = 0;
+	void __iomem		*mbase = musb->mregs;
+	struct musb_hw_ep	*hw_ep = musb->control_ep;
+	void __iomem		*epio = hw_ep->regs;
+	struct musb_qh		*qh = hw_ep->in_qh;
+	bool			complete = false;
+	irqreturn_t		retval = IRQ_NONE;
+
+	/* ep0 only has one queue, "in" */
+	urb = next_urb(qh);
+
+	musb_ep_select(mbase, 0);
+	csr = musb_readw(epio, MUSB_CSR0);
+	len = (csr & MUSB_CSR0_RXPKTRDY)
+			? musb_readb(epio, MUSB_COUNT0)
+			: 0;
+
+	dev_dbg(musb->controller, "<== csr0 %04x, qh %p, count %d, urb %p, stage %d\n",
+		csr, qh, len, urb, musb->ep0_stage);
+
+	/* if we just did status stage, we are done */
+	if (MUSB_EP0_STATUS == musb->ep0_stage) {
+		retval = IRQ_HANDLED;
+		complete = true;
+	}
+
+	/* prepare status */
+	if (csr & MUSB_CSR0_H_RXSTALL) {
+		dev_dbg(musb->controller, "STALLING ENDPOINT\n");
+		status = -EPIPE;
+
+	} else if (csr & MUSB_CSR0_H_ERROR) {
+		dev_dbg(musb->controller, "no response, csr0 %04x\n", csr);
+		status = -EPROTO;
+
+	} else if (csr & MUSB_CSR0_H_NAKTIMEOUT) {
+		dev_dbg(musb->controller, "control NAK timeout\n");
+
+		/* NOTE:  this code path would be a good place to PAUSE a
+		 * control transfer, if another one is queued, so that
+		 * ep0 is more likely to stay busy.  That's already done
+		 * for bulk RX transfers.
+		 *
+		 * if (qh->ring.next != &musb->control), then
+		 * we have a candidate... NAKing is *NOT* an error
+		 */
+		musb_writew(epio, MUSB_CSR0, 0);
+		retval = IRQ_HANDLED;
+	}
+
+	if (status) {
+		dev_dbg(musb->controller, "aborting\n");
+		retval = IRQ_HANDLED;
+		if (urb)
+			urb->status = status;
+		complete = true;
+
+		/* use the proper sequence to abort the transfer */
+		if (csr & MUSB_CSR0_H_REQPKT) {
+			csr &= ~MUSB_CSR0_H_REQPKT;
+			musb_writew(epio, MUSB_CSR0, csr);
+			csr &= ~MUSB_CSR0_H_NAKTIMEOUT;
+			musb_writew(epio, MUSB_CSR0, csr);
+		} else {
+			musb_h_ep0_flush_fifo(hw_ep);
+		}
+
+		musb_writeb(epio, MUSB_NAKLIMIT0, 0);
+
+		/* clear it */
+		musb_writew(epio, MUSB_CSR0, 0);
+	}
+
+	if (unlikely(!urb)) {
+		/* stop endpoint since we have no place for its data, this
+		 * SHOULD NEVER HAPPEN! */
+		ERR("no URB for end 0\n");
+
+		musb_h_ep0_flush_fifo(hw_ep);
+		goto done;
+	}
+
+	if (!complete) {
+		/* call common logic and prepare response */
+		if (musb_h_ep0_continue(musb, len, urb)) {
+			/* more packets required */
+			csr = (MUSB_EP0_IN == musb->ep0_stage)
+				?  MUSB_CSR0_H_REQPKT : MUSB_CSR0_TXPKTRDY;
+		} else {
+			/* data transfer complete; perform status phase */
+			if (usb_pipeout(urb->pipe)
+					|| !urb->transfer_buffer_length)
+				csr = MUSB_CSR0_H_STATUSPKT
+					| MUSB_CSR0_H_REQPKT;
+			else
+				csr = MUSB_CSR0_H_STATUSPKT
+					| MUSB_CSR0_TXPKTRDY;
+
+			/* flag status stage */
+			musb->ep0_stage = MUSB_EP0_STATUS;
+
+			dev_dbg(musb->controller, "ep0 STATUS, csr %04x\n", csr);
+
+		}
+		musb_writew(epio, MUSB_CSR0, csr);
+		retval = IRQ_HANDLED;
+	} else
+		musb->ep0_stage = MUSB_EP0_IDLE;
+
+	/* call completion handler if done */
+	if (complete)
+		musb_advance_schedule(musb, urb, hw_ep, 1);
+done:
+	return retval;
+}
+
+
+#ifdef CONFIG_USB_INVENTRA_DMA
+
+/* Host side TX (OUT) using Mentor DMA works as follows:
+	submit_urb ->
+		- if queue was empty, Program Endpoint
+		- ... which starts DMA to fifo in mode 1 or 0
+
+	DMA Isr (transfer complete) -> TxAvail()
+		- Stop DMA (~DmaEnab)	(<--- Alert ... currently happens
+					only in musb_cleanup_urb)
+		- TxPktRdy has to be set in mode 0 or for
+			short packets in mode 1.
+*/
+
+#endif
+
+/* Service a Tx-Available or dma completion irq for the endpoint */
+void musb_host_tx(struct musb *musb, u8 epnum)
+{
+	int			pipe;
+	bool			done = false;
+	u16			tx_csr;
+	size_t			length = 0;
+	size_t			offset = 0;
+	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
+	void __iomem		*epio = hw_ep->regs;
+	struct musb_qh		*qh = hw_ep->out_qh;
+	struct urb		*urb = next_urb(qh);
+	u32			status = 0;
+	void __iomem		*mbase = musb->mregs;
+	struct dma_channel	*dma;
+	bool			transfer_pending = false;
+
+	musb_ep_select(mbase, epnum);
+	tx_csr = musb_readw(epio, MUSB_TXCSR);
+
+	/* with CPPI, DMA sometimes triggers "extra" irqs */
+	if (!urb) {
+		dev_dbg(musb->controller, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
+		return;
+	}
+
+	pipe = urb->pipe;
+	dma = is_dma_capable() ? hw_ep->tx_channel : NULL;
+	dev_dbg(musb->controller, "OUT/TX%d end, csr %04x%s\n", epnum, tx_csr,
+			dma ? ", dma" : "");
+
+	/* check for errors */
+	if (tx_csr & MUSB_TXCSR_H_RXSTALL) {
+		/* dma was disabled, fifo flushed */
+		dev_dbg(musb->controller, "TX end %d stall\n", epnum);
+
+		/* stall; record URB status */
+		status = -EPIPE;
+
+	} else if (tx_csr & MUSB_TXCSR_H_ERROR) {
+		/* (NON-ISO) dma was disabled, fifo flushed */
+		dev_dbg(musb->controller, "TX 3strikes on ep=%d\n", epnum);
+
+		status = -ETIMEDOUT;
+
+	} else if (tx_csr & MUSB_TXCSR_H_NAKTIMEOUT) {
+		dev_dbg(musb->controller, "TX end=%d device not responding\n", epnum);
+
+		/* NOTE:  this code path would be a good place to PAUSE a
+		 * transfer, if there's some other (nonperiodic) tx urb
+		 * that could use this fifo.  (dma complicates it...)
+		 * That's already done for bulk RX transfers.
+		 *
+		 * if (bulk && qh->ring.next != &musb->out_bulk), then
+		 * we have a candidate... NAKing is *NOT* an error
+		 */
+		musb_ep_select(mbase, epnum);
+		musb_writew(epio, MUSB_TXCSR,
+				MUSB_TXCSR_H_WZC_BITS
+				| MUSB_TXCSR_TXPKTRDY);
+		return;
+	}
+
+	if (status) {
+		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
+			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
+			(void) musb->dma_controller->channel_abort(dma);
+		}
+
+		/* do the proper sequence to abort the transfer in the
+		 * usb core; the dma engine should already be stopped.
+		 */
+		musb_h_tx_flush_fifo(hw_ep);
+		tx_csr &= ~(MUSB_TXCSR_AUTOSET
+				| MUSB_TXCSR_DMAENAB
+				| MUSB_TXCSR_H_ERROR
+				| MUSB_TXCSR_H_RXSTALL
+				| MUSB_TXCSR_H_NAKTIMEOUT
+				);
+
+		musb_ep_select(mbase, epnum);
+		musb_writew(epio, MUSB_TXCSR, tx_csr);
+		/* REVISIT may need to clear FLUSHFIFO ... */
+		musb_writew(epio, MUSB_TXCSR, tx_csr);
+		musb_writeb(epio, MUSB_TXINTERVAL, 0);
+
+		done = true;
+	}
+
+	/* second cppi case */
+	if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
+		dev_dbg(musb->controller, "extra TX%d ready, csr %04x\n", epnum, tx_csr);
+		return;
+	}
+
+	if (is_dma_capable() && dma && !status) {
+		/*
+		 * DMA has completed.  But if we're using DMA mode 1 (multi
+		 * packet DMA), we need a terminal TXPKTRDY interrupt before
+		 * we can consider this transfer completed, lest we trash
+		 * its last packet when writing the next URB's data.  So we
+		 * switch back to mode 0 to get that interrupt; we'll come
+		 * back here once it happens.
+		 */
+		if (tx_csr & MUSB_TXCSR_DMAMODE) {
+			/*
+			 * We shouldn't clear DMAMODE with DMAENAB set; so
+			 * clear them in a safe order.  That should be OK
+			 * once TXPKTRDY has been set (and I've never seen
+			 * it being 0 at this moment -- DMA interrupt latency
+			 * is significant) but if it hasn't been then we have
+			 * no choice but to stop being polite and ignore the
+			 * programmer's guide... :-)
+			 *
+			 * Note that we must write TXCSR with TXPKTRDY cleared
+			 * in order not to re-trigger the packet send (this bit
+			 * can't be cleared by CPU), and there's another caveat:
+			 * TXPKTRDY may be set shortly and then cleared in the
+			 * double-buffered FIFO mode, so we do an extra TXCSR
+			 * read for debouncing...
+			 */
+			tx_csr &= musb_readw(epio, MUSB_TXCSR);
+			if (tx_csr & MUSB_TXCSR_TXPKTRDY) {
+				tx_csr &= ~(MUSB_TXCSR_DMAENAB |
+					    MUSB_TXCSR_TXPKTRDY);
+				musb_writew(epio, MUSB_TXCSR,
+					    tx_csr | MUSB_TXCSR_H_WZC_BITS);
+			}
+			tx_csr &= ~(MUSB_TXCSR_DMAMODE |
+				    MUSB_TXCSR_TXPKTRDY);
+			musb_writew(epio, MUSB_TXCSR,
+				    tx_csr | MUSB_TXCSR_H_WZC_BITS);
+
+			/*
+			 * There is no guarantee that we'll get an interrupt
+			 * after clearing DMAMODE as we might have done this
+			 * too late (after TXPKTRDY was cleared by controller).
+			 * Re-read TXCSR as we have spoiled its previous value.
+			 */
+			tx_csr = musb_readw(epio, MUSB_TXCSR);
+		}
+
+		/*
+		 * We may get here from a DMA completion or TXPKTRDY interrupt.
+		 * In any case, we must check the FIFO status here and bail out
+		 * only if the FIFO still has data -- that should prevent the
+		 * "missed" TXPKTRDY interrupts and deal with double-buffered
+		 * FIFO mode too...
+		 */
+		if (tx_csr & (MUSB_TXCSR_FIFONOTEMPTY | MUSB_TXCSR_TXPKTRDY)) {
+			dev_dbg(musb->controller, "DMA complete but packet still in FIFO, "
+			    "CSR %04x\n", tx_csr);
+			return;
+		}
+	}
+
+	if (!status || dma || usb_pipeisoc(pipe)) {
+		if (dma)
+			length = dma->actual_len;
+		else
+			length = qh->segsize;
+		qh->offset += length;
+
+		if (usb_pipeisoc(pipe)) {
+#ifndef __UBOOT__
+			struct usb_iso_packet_descriptor	*d;
+
+			d = urb->iso_frame_desc + qh->iso_idx;
+			d->actual_length = length;
+			d->status = status;
+			if (++qh->iso_idx >= urb->number_of_packets) {
+				done = true;
+			} else {
+				d++;
+				offset = d->offset;
+				length = d->length;
+			}
+#endif
+		} else if (dma && urb->transfer_buffer_length == qh->offset) {
+			done = true;
+		} else {
+			/* see if we need to send more data, or ZLP */
+			if (qh->segsize < qh->maxpacket)
+				done = true;
+			else if (qh->offset == urb->transfer_buffer_length
+					&& !(urb->transfer_flags
+						& URB_ZERO_PACKET))
+				done = true;
+			if (!done) {
+				offset = qh->offset;
+				length = urb->transfer_buffer_length - offset;
+				transfer_pending = true;
+			}
+		}
+	}
+
+	/* urb->status != -EINPROGRESS means request has been faulted,
+	 * so we must abort this transfer after cleanup
+	 */
+	if (urb->status != -EINPROGRESS) {
+		done = true;
+		if (status == 0)
+			status = urb->status;
+	}
+
+	if (done) {
+		/* set status */
+		urb->status = status;
+		urb->actual_length = qh->offset;
+		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_OUT);
+		return;
+	} else if ((usb_pipeisoc(pipe) || transfer_pending) && dma) {
+		if (musb_tx_dma_program(musb->dma_controller, hw_ep, qh, urb,
+				offset, length)) {
+			if (is_cppi_enabled() || tusb_dma_omap())
+				musb_h_tx_dma_start(hw_ep);
+			return;
+		}
+	} else	if (tx_csr & MUSB_TXCSR_DMAENAB) {
+		dev_dbg(musb->controller, "not complete, but DMA enabled?\n");
+		return;
+	}
+
+	/*
+	 * PIO: start next packet in this URB.
+	 *
+	 * REVISIT: some docs say that when hw_ep->tx_double_buffered,
+	 * (and presumably, FIFO is not half-full) we should write *two*
+	 * packets before updating TXCSR; other docs disagree...
+	 */
+	if (length > qh->maxpacket)
+		length = qh->maxpacket;
+	/* Unmap the buffer so that CPU can use it */
+	usb_hcd_unmap_urb_for_dma(musb_to_hcd(musb), urb);
+	musb_write_fifo(hw_ep, length, urb->transfer_buffer + offset);
+	qh->segsize = length;
+
+	musb_ep_select(mbase, epnum);
+	musb_writew(epio, MUSB_TXCSR,
+			MUSB_TXCSR_H_WZC_BITS | MUSB_TXCSR_TXPKTRDY);
+}
+
+
+#ifdef CONFIG_USB_INVENTRA_DMA
+
+/* Host side RX (IN) using Mentor DMA works as follows:
+	submit_urb ->
+		- if queue was empty, ProgramEndpoint
+		- first IN token is sent out (by setting ReqPkt)
+	LinuxIsr -> RxReady()
+	/\	=> first packet is received
+	|	- Set in mode 0 (DmaEnab, ~ReqPkt)
+	|		-> DMA Isr (transfer complete) -> RxReady()
+	|		    - Ack receive (~RxPktRdy), turn off DMA (~DmaEnab)
+	|		    - if urb not complete, send next IN token (ReqPkt)
+	|			   |		else complete urb.
+	|			   |
+	---------------------------
+ *
+ * Nuances of mode 1:
+ *	For short packets, no ack (+RxPktRdy) is sent automatically
+ *	(even if AutoClear is ON)
+ *	For full packets, ack (~RxPktRdy) and next IN token (+ReqPkt) is sent
+ *	automatically => major problem, as collecting the next packet becomes
+ *	difficult. Hence mode 1 is not used.
+ *
+ * REVISIT
+ *	All we care about at this driver level is that
+ *       (a) all URBs terminate with REQPKT cleared and fifo(s) empty;
+ *       (b) termination conditions are: short RX, or buffer full;
+ *       (c) fault modes include
+ *           - iff URB_SHORT_NOT_OK, short RX status is -EREMOTEIO.
+ *             (and that endpoint's dma queue stops immediately)
+ *           - overflow (full, PLUS more bytes in the terminal packet)
+ *
+ *	So for example, usb-storage sets URB_SHORT_NOT_OK, and would
+ *	thus be a great candidate for using mode 1 ... for all but the
+ *	last packet of one URB's transfer.
+ */
+
+#endif
+
+/* Schedule next QH from musb->in_bulk and move the current qh to
+ * the end; avoids starvation for other endpoints.
+ */
+static void musb_bulk_rx_nak_timeout(struct musb *musb, struct musb_hw_ep *ep)
+{
+	struct dma_channel	*dma;
+	struct urb		*urb;
+	void __iomem		*mbase = musb->mregs;
+	void __iomem		*epio = ep->regs;
+	struct musb_qh		*cur_qh, *next_qh;
+	u16			rx_csr;
+
+	musb_ep_select(mbase, ep->epnum);
+	dma = is_dma_capable() ? ep->rx_channel : NULL;
+
+	/* clear nak timeout bit */
+	rx_csr = musb_readw(epio, MUSB_RXCSR);
+	rx_csr |= MUSB_RXCSR_H_WZC_BITS;
+	rx_csr &= ~MUSB_RXCSR_DATAERROR;
+	musb_writew(epio, MUSB_RXCSR, rx_csr);
+
+	cur_qh = first_qh(&musb->in_bulk);
+	if (cur_qh) {
+		urb = next_urb(cur_qh);
+		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
+			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
+			musb->dma_controller->channel_abort(dma);
+			urb->actual_length += dma->actual_len;
+			dma->actual_len = 0L;
+		}
+		musb_save_toggle(cur_qh, 1, urb);
+
+		/* move cur_qh to end of queue */
+		list_move_tail(&cur_qh->ring, &musb->in_bulk);
+
+		/* get the next qh from musb->in_bulk */
+		next_qh = first_qh(&musb->in_bulk);
+
+		/* set rx_reinit and schedule the next qh */
+		ep->rx_reinit = 1;
+		musb_start_urb(musb, 1, next_qh);
+	}
+}
+
+/*
+ * Service an RX interrupt for the given IN endpoint; docs cover bulk, iso,
+ * and high-bandwidth IN transfer cases.
+ */
+void musb_host_rx(struct musb *musb, u8 epnum)
+{
+	struct urb		*urb;
+	struct musb_hw_ep	*hw_ep = musb->endpoints + epnum;
+	void __iomem		*epio = hw_ep->regs;
+	struct musb_qh		*qh = hw_ep->in_qh;
+	size_t			xfer_len;
+	void __iomem		*mbase = musb->mregs;
+	int			pipe;
+	u16			rx_csr, val;
+	bool			iso_err = false;
+	bool			done = false;
+	u32			status;
+	struct dma_channel	*dma;
+
+	musb_ep_select(mbase, epnum);
+
+	urb = next_urb(qh);
+	dma = is_dma_capable() ? hw_ep->rx_channel : NULL;
+	status = 0;
+	xfer_len = 0;
+
+	rx_csr = musb_readw(epio, MUSB_RXCSR);
+	val = rx_csr;
+
+	if (unlikely(!urb)) {
+		/* REVISIT -- THIS SHOULD NEVER HAPPEN ... but, at least
+		 * usbtest #11 (unlinks) triggers it regularly, sometimes
+		 * with fifo full.  (Only with DMA??)
+		 */
+		dev_dbg(musb->controller, "BOGUS RX%d ready, csr %04x, count %d\n", epnum, val,
+			musb_readw(epio, MUSB_RXCOUNT));
+		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
+		return;
+	}
+
+	pipe = urb->pipe;
+
+	dev_dbg(musb->controller, "<== hw %d rxcsr %04x, urb actual %d (+dma %zu)\n",
+		epnum, rx_csr, urb->actual_length,
+		dma ? dma->actual_len : 0);
+
+	/* check for errors, concurrent stall & unlink is not really
+	 * handled yet! */
+	if (rx_csr & MUSB_RXCSR_H_RXSTALL) {
+		dev_dbg(musb->controller, "RX end %d STALL\n", epnum);
+
+		/* stall; record URB status */
+		status = -EPIPE;
+
+	} else if (rx_csr & MUSB_RXCSR_H_ERROR) {
+		dev_dbg(musb->controller, "end %d RX proto error\n", epnum);
+
+		status = -EPROTO;
+		musb_writeb(epio, MUSB_RXINTERVAL, 0);
+
+	} else if (rx_csr & MUSB_RXCSR_DATAERROR) {
+
+		if (USB_ENDPOINT_XFER_ISOC != qh->type) {
+			dev_dbg(musb->controller, "RX end %d NAK timeout\n", epnum);
+
+			/* NOTE: NAKing is *NOT* an error, so we want to
+			 * continue.  Except ... if there's a request for
+			 * another QH, use that instead of starving it.
+			 *
+			 * Devices like Ethernet and serial adapters keep
+			 * reads posted at all times, which will starve
+			 * other devices without this logic.
+			 */
+			if (usb_pipebulk(urb->pipe)
+					&& qh->mux == 1
+					&& !list_is_singular(&musb->in_bulk)) {
+				musb_bulk_rx_nak_timeout(musb, hw_ep);
+				return;
+			}
+			musb_ep_select(mbase, epnum);
+			rx_csr |= MUSB_RXCSR_H_WZC_BITS;
+			rx_csr &= ~MUSB_RXCSR_DATAERROR;
+			musb_writew(epio, MUSB_RXCSR, rx_csr);
+
+			goto finish;
+		} else {
+			dev_dbg(musb->controller, "RX end %d ISO data error\n", epnum);
+			/* packet error reported later */
+			iso_err = true;
+		}
+	} else if (rx_csr & MUSB_RXCSR_INCOMPRX) {
+		dev_dbg(musb->controller, "end %d high bandwidth incomplete ISO packet RX\n",
+				epnum);
+		status = -EPROTO;
+	}
+
+	/* faults abort the transfer */
+	if (status) {
+		/* clean up dma and collect transfer count */
+		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
+			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
+			(void) musb->dma_controller->channel_abort(dma);
+			xfer_len = dma->actual_len;
+		}
+		musb_h_flush_rxfifo(hw_ep, MUSB_RXCSR_CLRDATATOG);
+		musb_writeb(epio, MUSB_RXINTERVAL, 0);
+		done = true;
+		goto finish;
+	}
+
+	if (unlikely(dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY)) {
+		/* SHOULD NEVER HAPPEN ... but at least DaVinci has done it */
+		ERR("RX%d dma busy, csr %04x\n", epnum, rx_csr);
+		goto finish;
+	}
+
+	/* thorough shutdown for now ... given more precise fault handling
+	 * and better queueing support, we might keep a DMA pipeline going
+	 * while processing this irq for earlier completions.
+	 */
+
+	/* FIXME this is _way_ too much in-line logic for Mentor DMA */
+
+#ifndef CONFIG_USB_INVENTRA_DMA
+	if (rx_csr & MUSB_RXCSR_H_REQPKT)  {
+		/* REVISIT this happened for a while on some short reads...
+		 * the cleanup still needs investigation... looks bad...
+		 * and also duplicates dma cleanup code above ... plus,
+		 * shouldn't this be the "half full" double buffer case?
+		 */
+		if (dma_channel_status(dma) == MUSB_DMA_STATUS_BUSY) {
+			dma->status = MUSB_DMA_STATUS_CORE_ABORT;
+			(void) musb->dma_controller->channel_abort(dma);
+			xfer_len = dma->actual_len;
+			done = true;
+		}
+
+		dev_dbg(musb->controller, "RXCSR%d %04x, reqpkt, len %zu%s\n", epnum, rx_csr,
+				xfer_len, dma ? ", dma" : "");
+		rx_csr &= ~MUSB_RXCSR_H_REQPKT;
+
+		musb_ep_select(mbase, epnum);
+		musb_writew(epio, MUSB_RXCSR,
+				MUSB_RXCSR_H_WZC_BITS | rx_csr);
+	}
+#endif
+	if (dma && (rx_csr & MUSB_RXCSR_DMAENAB)) {
+		xfer_len = dma->actual_len;
+
+		val &= ~(MUSB_RXCSR_DMAENAB
+			| MUSB_RXCSR_H_AUTOREQ
+			| MUSB_RXCSR_AUTOCLEAR
+			| MUSB_RXCSR_RXPKTRDY);
+		musb_writew(hw_ep->regs, MUSB_RXCSR, val);
+
+#ifdef CONFIG_USB_INVENTRA_DMA
+		if (usb_pipeisoc(pipe)) {
+			struct usb_iso_packet_descriptor *d;
+
+			d = urb->iso_frame_desc + qh->iso_idx;
+			d->actual_length = xfer_len;
+
+			/* even if there was an error, we did the dma
+			 * for iso_frame_desc->length
+			 */
+			if (d->status != -EILSEQ && d->status != -EOVERFLOW)
+				d->status = 0;
+
+			if (++qh->iso_idx >= urb->number_of_packets)
+				done = true;
+			else
+				done = false;
+
+		} else  {
+		/* done if urb buffer is full or short packet is recd */
+		done = (urb->actual_length + xfer_len >=
+				urb->transfer_buffer_length
+			|| dma->actual_len < qh->maxpacket);
+		}
+
+		/* send IN token for next packet, without AUTOREQ */
+		if (!done) {
+			val |= MUSB_RXCSR_H_REQPKT;
+			musb_writew(epio, MUSB_RXCSR,
+				MUSB_RXCSR_H_WZC_BITS | val);
+		}
+
+		dev_dbg(musb->controller, "ep %d dma %s, rxcsr %04x, rxcount %d\n", epnum,
+			done ? "off" : "reset",
+			musb_readw(epio, MUSB_RXCSR),
+			musb_readw(epio, MUSB_RXCOUNT));
+#else
+		done = true;
+#endif
+	} else if (urb->status == -EINPROGRESS) {
+		/* if no errors, be sure a packet is ready for unloading */
+		if (unlikely(!(rx_csr & MUSB_RXCSR_RXPKTRDY))) {
+			status = -EPROTO;
+			ERR("Rx interrupt with no errors or packet!\n");
+
+			/* FIXME this is another "SHOULD NEVER HAPPEN" */
+
+/* SCRUB (RX) */
+			/* do the proper sequence to abort the transfer */
+			musb_ep_select(mbase, epnum);
+			val &= ~MUSB_RXCSR_H_REQPKT;
+			musb_writew(epio, MUSB_RXCSR, val);
+			goto finish;
+		}
+
+		/* we are expecting IN packets */
+#ifdef CONFIG_USB_INVENTRA_DMA
+		if (dma) {
+			struct dma_controller	*c;
+			u16			rx_count;
+			int			ret, length;
+			dma_addr_t		buf;
+
+			rx_count = musb_readw(epio, MUSB_RXCOUNT);
+
+			dev_dbg(musb->controller, "RX%d count %d, buffer 0x%x len %d/%d\n",
+					epnum, rx_count,
+					urb->transfer_dma
+						+ urb->actual_length,
+					qh->offset,
+					urb->transfer_buffer_length);
+
+			c = musb->dma_controller;
+
+			if (usb_pipeisoc(pipe)) {
+				int d_status = 0;
+				struct usb_iso_packet_descriptor *d;
+
+				d = urb->iso_frame_desc + qh->iso_idx;
+
+				if (iso_err) {
+					d_status = -EILSEQ;
+					urb->error_count++;
+				}
+				if (rx_count > d->length) {
+					if (d_status == 0) {
+						d_status = -EOVERFLOW;
+						urb->error_count++;
+					}
+					dev_dbg(musb->controller, "** OVERFLOW %d into %d\n",\
+					    rx_count, d->length);
+
+					length = d->length;
+				} else
+					length = rx_count;
+				d->status = d_status;
+				buf = urb->transfer_dma + d->offset;
+			} else {
+				length = rx_count;
+				buf = urb->transfer_dma +
+						urb->actual_length;
+			}
+
+			dma->desired_mode = 0;
+#ifdef USE_MODE1
+			/* because of the issue below, mode 1 will
+			 * only rarely behave with correct semantics.
+			 */
+			if ((urb->transfer_flags &
+						URB_SHORT_NOT_OK)
+				&& (urb->transfer_buffer_length -
+						urb->actual_length)
+					> qh->maxpacket)
+				dma->desired_mode = 1;
+			if (rx_count < hw_ep->max_packet_sz_rx) {
+				length = rx_count;
+				dma->desired_mode = 0;
+			} else {
+				length = urb->transfer_buffer_length;
+			}
+#endif
+
+/* Disadvantage of using mode 1:
+ *	It's basically usable only for mass storage class; essentially all
+ *	other protocols also terminate transfers on short packets.
+ *
+ * Details:
+ *	An extra IN token is sent at the end of the transfer (due to AUTOREQ)
+ *	If you try to use mode 1 for (transfer_buffer_length - 512), and try
+ *	to use the extra IN token to grab the last packet using mode 0, then
+ *	the problem is that you cannot be sure when the device will send the
+ *	last packet and RxPktRdy set. Sometimes the packet is recd too soon
+ *	such that it gets lost when RxCSR is re-set at the end of the mode 1
+ *	transfer, while sometimes it is recd just a little late so that if you
+ *	try to configure for mode 0 soon after the mode 1 transfer is
+ *	completed, you will find rxcount 0. Okay, so you might think why not
+ *	wait for an interrupt when the pkt is recd. Well, you won't get any!
+ */
+
+			val = musb_readw(epio, MUSB_RXCSR);
+			val &= ~MUSB_RXCSR_H_REQPKT;
+
+			if (dma->desired_mode == 0)
+				val &= ~MUSB_RXCSR_H_AUTOREQ;
+			else
+				val |= MUSB_RXCSR_H_AUTOREQ;
+			val |= MUSB_RXCSR_DMAENAB;
+
+			/* autoclear shouldn't be set in high bandwidth */
+			if (qh->hb_mult == 1)
+				val |= MUSB_RXCSR_AUTOCLEAR;
+
+			musb_writew(epio, MUSB_RXCSR,
+				MUSB_RXCSR_H_WZC_BITS | val);
+
+			/* REVISIT if when actual_length != 0,
+			 * transfer_buffer_length needs to be
+			 * adjusted first...
+			 */
+			ret = c->channel_program(
+				dma, qh->maxpacket,
+				dma->desired_mode, buf, length);
+
+			if (!ret) {
+				c->channel_release(dma);
+				hw_ep->rx_channel = NULL;
+				dma = NULL;
+				val = musb_readw(epio, MUSB_RXCSR);
+				val &= ~(MUSB_RXCSR_DMAENAB
+					| MUSB_RXCSR_H_AUTOREQ
+					| MUSB_RXCSR_AUTOCLEAR);
+				musb_writew(epio, MUSB_RXCSR, val);
+			}
+		}
+#endif	/* Mentor DMA */
+
+		if (!dma) {
+			/* Unmap the buffer so that CPU can use it */
+			usb_hcd_unmap_urb_for_dma(musb_to_hcd(musb), urb);
+			done = musb_host_packet_rx(musb, urb,
+					epnum, iso_err);
+			dev_dbg(musb->controller, "read %spacket\n", done ? "last " : "");
+		}
+	}
+
+finish:
+	urb->actual_length += xfer_len;
+	qh->offset += xfer_len;
+	if (done) {
+		if (urb->status == -EINPROGRESS)
+			urb->status = status;
+		musb_advance_schedule(musb, urb, hw_ep, USB_DIR_IN);
+	}
+}
+
+/* schedule nodes correspond to peripheral endpoints, like an OHCI QH.
+ * the software schedule associates multiple such nodes with a given
+ * host side hardware endpoint + direction; scheduling may activate
+ * that hardware endpoint.
+ */
+static int musb_schedule(
+	struct musb		*musb,
+	struct musb_qh		*qh,
+	int			is_in)
+{
+	int			idle;
+	int			best_diff;
+	int			best_end, epnum;
+	struct musb_hw_ep	*hw_ep = NULL;
+	struct list_head	*head = NULL;
+	u8			toggle;
+	u8			txtype;
+	struct urb		*urb = next_urb(qh);
+
+	/* use fixed hardware for control and bulk */
+	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
+		head = &musb->control;
+		hw_ep = musb->control_ep;
+		goto success;
+	}
+
+	/* else, periodic transfers get muxed to other endpoints */
+
+	/*
+	 * We know this qh hasn't been scheduled, so all we need to do
+	 * is choose which hardware endpoint to put it on ...
+	 *
+	 * REVISIT what we really want here is a regular schedule tree
+	 * like e.g. OHCI uses.
+	 */
+	best_diff = 4096;
+	best_end = -1;
+
+	for (epnum = 1, hw_ep = musb->endpoints + 1;
+			epnum < musb->nr_endpoints;
+			epnum++, hw_ep++) {
+		int	diff;
+
+		if (musb_ep_get_qh(hw_ep, is_in) != NULL)
+			continue;
+
+		if (hw_ep == musb->bulk_ep)
+			continue;
+
+		if (is_in)
+			diff = hw_ep->max_packet_sz_rx;
+		else
+			diff = hw_ep->max_packet_sz_tx;
+		diff -= (qh->maxpacket * qh->hb_mult);
+
+		if (diff >= 0 && best_diff > diff) {
+
+			/*
+			 * Mentor controller has a bug in that if we schedule
+			 * a BULK Tx transfer on an endpoint that had earlier
+			 * handled ISOC then the BULK transfer has to start on
+			 * a zero toggle.  If the BULK transfer starts on a 1
+			 * toggle then this transfer will fail as the mentor
+			 * controller starts the Bulk transfer on a 0 toggle
+			 * irrespective of the programming of the toggle bits
+			 * in the TXCSR register.  Check for this condition
+			 * while allocating the EP for a Tx Bulk transfer.  If
+			 * so skip this EP.
+			 */
+			hw_ep = musb->endpoints + epnum;
+			toggle = usb_gettoggle(urb->dev, qh->epnum, !is_in);
+			txtype = (musb_readb(hw_ep->regs, MUSB_TXTYPE)
+					>> 4) & 0x3;
+			if (!is_in && (qh->type == USB_ENDPOINT_XFER_BULK) &&
+				toggle && (txtype == USB_ENDPOINT_XFER_ISOC))
+				continue;
+
+			best_diff = diff;
+			best_end = epnum;
+		}
+	}
+	/* use bulk reserved ep1 if no other ep is free */
+	if (best_end < 0 && qh->type == USB_ENDPOINT_XFER_BULK) {
+		hw_ep = musb->bulk_ep;
+		if (is_in)
+			head = &musb->in_bulk;
+		else
+			head = &musb->out_bulk;
+
+		/* Enable bulk RX NAK timeout scheme when bulk requests are
+		 * multiplexed.  This scheme doen't work in high speed to full
+		 * speed scenario as NAK interrupts are not coming from a
+		 * full speed device connected to a high speed device.
+		 * NAK timeout interval is 8 (128 uframe or 16ms) for HS and
+		 * 4 (8 frame or 8ms) for FS device.
+		 */
+		if (is_in && qh->dev)
+			qh->intv_reg =
+				(USB_SPEED_HIGH == qh->dev->speed) ? 8 : 4;
+		goto success;
+	} else if (best_end < 0) {
+		return -ENOSPC;
+	}
+
+	idle = 1;
+	qh->mux = 0;
+	hw_ep = musb->endpoints + best_end;
+	dev_dbg(musb->controller, "qh %p periodic slot %d\n", qh, best_end);
+success:
+	if (head) {
+		idle = list_empty(head);
+		list_add_tail(&qh->ring, head);
+		qh->mux = 1;
+	}
+	qh->hw_ep = hw_ep;
+	qh->hep->hcpriv = qh;
+	if (idle)
+		musb_start_urb(musb, is_in, qh);
+	return 0;
+}
+
+#ifdef __UBOOT__
+/* check if transaction translator is needed for device */
+static int tt_needed(struct musb *musb, struct usb_device *dev)
+{
+	if ((musb_readb(musb->mregs, MUSB_POWER) & MUSB_POWER_HSMODE) &&
+			(dev->speed < USB_SPEED_HIGH))
+		return 1;
+	return 0;
+}
+#endif
+
+#ifndef __UBOOT__
+static int musb_urb_enqueue(
+#else
+int musb_urb_enqueue(
+#endif
+	struct usb_hcd			*hcd,
+	struct urb			*urb,
+	gfp_t				mem_flags)
+{
+	unsigned long			flags;
+	struct musb			*musb = hcd_to_musb(hcd);
+	struct usb_host_endpoint	*hep = urb->ep;
+	struct musb_qh			*qh;
+	struct usb_endpoint_descriptor	*epd = &hep->desc;
+	int				ret;
+	unsigned			type_reg;
+	unsigned			interval;
+
+	/* host role must be active */
+	if (!is_host_active(musb) || !musb->is_active)
+		return -ENODEV;
+
+	spin_lock_irqsave(&musb->lock, flags);
+	ret = usb_hcd_link_urb_to_ep(hcd, urb);
+	qh = ret ? NULL : hep->hcpriv;
+	if (qh)
+		urb->hcpriv = qh;
+	spin_unlock_irqrestore(&musb->lock, flags);
+
+	/* DMA mapping was already done, if needed, and this urb is on
+	 * hep->urb_list now ... so we're done, unless hep wasn't yet
+	 * scheduled onto a live qh.
+	 *
+	 * REVISIT best to keep hep->hcpriv valid until the endpoint gets
+	 * disabled, testing for empty qh->ring and avoiding qh setup costs
+	 * except for the first urb queued after a config change.
+	 */
+	if (qh || ret)
+		return ret;
+
+	/* Allocate and initialize qh, minimizing the work done each time
+	 * hw_ep gets reprogrammed, or with irqs blocked.  Then schedule it.
+	 *
+	 * REVISIT consider a dedicated qh kmem_cache, so it's harder
+	 * for bugs in other kernel code to break this driver...
+	 */
+	qh = kzalloc(sizeof *qh, mem_flags);
+	if (!qh) {
+		spin_lock_irqsave(&musb->lock, flags);
+		usb_hcd_unlink_urb_from_ep(hcd, urb);
+		spin_unlock_irqrestore(&musb->lock, flags);
+		return -ENOMEM;
+	}
+
+	qh->hep = hep;
+	qh->dev = urb->dev;
+	INIT_LIST_HEAD(&qh->ring);
+	qh->is_ready = 1;
+
+	qh->maxpacket = usb_endpoint_maxp(epd);
+	qh->type = usb_endpoint_type(epd);
+
+	/* Bits 11 & 12 of wMaxPacketSize encode high bandwidth multiplier.
+	 * Some musb cores don't support high bandwidth ISO transfers; and
+	 * we don't (yet!) support high bandwidth interrupt transfers.
+	 */
+	qh->hb_mult = 1 + ((qh->maxpacket >> 11) & 0x03);
+	if (qh->hb_mult > 1) {
+		int ok = (qh->type == USB_ENDPOINT_XFER_ISOC);
+
+		if (ok)
+			ok = (usb_pipein(urb->pipe) && musb->hb_iso_rx)
+				|| (usb_pipeout(urb->pipe) && musb->hb_iso_tx);
+		if (!ok) {
+			ret = -EMSGSIZE;
+			goto done;
+		}
+		qh->maxpacket &= 0x7ff;
+	}
+
+	qh->epnum = usb_endpoint_num(epd);
+
+	/* NOTE: urb->dev->devnum is wrong during SET_ADDRESS */
+	qh->addr_reg = (u8) usb_pipedevice(urb->pipe);
+
+	/* precompute rxtype/txtype/type0 register */
+	type_reg = (qh->type << 4) | qh->epnum;
+	switch (urb->dev->speed) {
+	case USB_SPEED_LOW:
+		type_reg |= 0xc0;
+		break;
+	case USB_SPEED_FULL:
+		type_reg |= 0x80;
+		break;
+	default:
+		type_reg |= 0x40;
+	}
+	qh->type_reg = type_reg;
+
+	/* Precompute RXINTERVAL/TXINTERVAL register */
+	switch (qh->type) {
+	case USB_ENDPOINT_XFER_INT:
+		/*
+		 * Full/low speeds use the  linear encoding,
+		 * high speed uses the logarithmic encoding.
+		 */
+		if (urb->dev->speed <= USB_SPEED_FULL) {
+			interval = max_t(u8, epd->bInterval, 1);
+			break;
+		}
+		/* FALLTHROUGH */
+	case USB_ENDPOINT_XFER_ISOC:
+		/* ISO always uses logarithmic encoding */
+		interval = min_t(u8, epd->bInterval, 16);
+		break;
+	default:
+		/* REVISIT we actually want to use NAK limits, hinting to the
+		 * transfer scheduling logic to try some other qh, e.g. try
+		 * for 2 msec first:
+		 *
+		 * interval = (USB_SPEED_HIGH == urb->dev->speed) ? 16 : 2;
+		 *
+		 * The downside of disabling this is that transfer scheduling
+		 * gets VERY unfair for nonperiodic transfers; a misbehaving
+		 * peripheral could make that hurt.  That's perfectly normal
+		 * for reads from network or serial adapters ... so we have
+		 * partial NAKlimit support for bulk RX.
+		 *
+		 * The upside of disabling it is simpler transfer scheduling.
+		 */
+		interval = 0;
+	}
+	qh->intv_reg = interval;
+
+	/* precompute addressing for external hub/tt ports */
+	if (musb->is_multipoint) {
+		struct usb_device	*parent = urb->dev->parent;
+
+#ifndef __UBOOT__
+		if (parent != hcd->self.root_hub) {
+#else
+		if (parent) {
+#endif
+			qh->h_addr_reg = (u8) parent->devnum;
+
+#ifndef __UBOOT__
+			/* set up tt info if needed */
+			if (urb->dev->tt) {
+				qh->h_port_reg = (u8) urb->dev->ttport;
+				if (urb->dev->tt->hub)
+					qh->h_addr_reg =
+						(u8) urb->dev->tt->hub->devnum;
+				if (urb->dev->tt->multi)
+					qh->h_addr_reg |= 0x80;
+			}
+#else
+			if (tt_needed(musb, urb->dev)) {
+				u16 hub_port = find_tt(urb->dev);
+				qh->h_addr_reg = (u8) (hub_port >> 8);
+				qh->h_port_reg = (u8) (hub_port & 0xff);
+			}
+#endif
+		}
+	}
+
+	/* invariant: hep->hcpriv is null OR the qh that's already scheduled.
+	 * until we get real dma queues (with an entry for each urb/buffer),
+	 * we only have work to do in the former case.
+	 */
+	spin_lock_irqsave(&musb->lock, flags);
+	if (hep->hcpriv) {
+		/* some concurrent activity submitted another urb to hep...
+		 * odd, rare, error prone, but legal.
+		 */
+		kfree(qh);
+		qh = NULL;
+		ret = 0;
+	} else
+		ret = musb_schedule(musb, qh,
+				epd->bEndpointAddress & USB_ENDPOINT_DIR_MASK);
+
+	if (ret == 0) {
+		urb->hcpriv = qh;
+		/* FIXME set urb->start_frame for iso/intr, it's tested in
+		 * musb_start_urb(), but otherwise only konicawc cares ...
+		 */
+	}
+	spin_unlock_irqrestore(&musb->lock, flags);
+
+done:
+	if (ret != 0) {
+		spin_lock_irqsave(&musb->lock, flags);
+		usb_hcd_unlink_urb_from_ep(hcd, urb);
+		spin_unlock_irqrestore(&musb->lock, flags);
+		kfree(qh);
+	}
+	return ret;
+}
+
+
+#ifndef __UBOOT__
+/*
+ * abort a transfer that's at the head of a hardware queue.
+ * called with controller locked, irqs blocked
+ * that hardware queue advances to the next transfer, unless prevented
+ */
+static int musb_cleanup_urb(struct urb *urb, struct musb_qh *qh)
+{
+	struct musb_hw_ep	*ep = qh->hw_ep;
+	struct musb		*musb = ep->musb;
+	void __iomem		*epio = ep->regs;
+	unsigned		hw_end = ep->epnum;
+	void __iomem		*regs = ep->musb->mregs;
+	int			is_in = usb_pipein(urb->pipe);
+	int			status = 0;
+	u16			csr;
+
+	musb_ep_select(regs, hw_end);
+
+	if (is_dma_capable()) {
+		struct dma_channel	*dma;
+
+		dma = is_in ? ep->rx_channel : ep->tx_channel;
+		if (dma) {
+			status = ep->musb->dma_controller->channel_abort(dma);
+			dev_dbg(musb->controller,
+				"abort %cX%d DMA for urb %p --> %d\n",
+				is_in ? 'R' : 'T', ep->epnum,
+				urb, status);
+			urb->actual_length += dma->actual_len;
+		}
+	}
+
+	/* turn off DMA requests, discard state, stop polling ... */
+	if (ep->epnum && is_in) {
+		/* giveback saves bulk toggle */
+		csr = musb_h_flush_rxfifo(ep, 0);
+
+		/* REVISIT we still get an irq; should likely clear the
+		 * endpoint's irq status here to avoid bogus irqs.
+		 * clearing that status is platform-specific...
+		 */
+	} else if (ep->epnum) {
+		musb_h_tx_flush_fifo(ep);
+		csr = musb_readw(epio, MUSB_TXCSR);
+		csr &= ~(MUSB_TXCSR_AUTOSET
+			| MUSB_TXCSR_DMAENAB
+			| MUSB_TXCSR_H_RXSTALL
+			| MUSB_TXCSR_H_NAKTIMEOUT
+			| MUSB_TXCSR_H_ERROR
+			| MUSB_TXCSR_TXPKTRDY);
+		musb_writew(epio, MUSB_TXCSR, csr);
+		/* REVISIT may need to clear FLUSHFIFO ... */
+		musb_writew(epio, MUSB_TXCSR, csr);
+		/* flush cpu writebuffer */
+		csr = musb_readw(epio, MUSB_TXCSR);
+	} else  {
+		musb_h_ep0_flush_fifo(ep);
+	}
+	if (status == 0)
+		musb_advance_schedule(ep->musb, urb, ep, is_in);
+	return status;
+}
+
+static int musb_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
+{
+	struct musb		*musb = hcd_to_musb(hcd);
+	struct musb_qh		*qh;
+	unsigned long		flags;
+	int			is_in  = usb_pipein(urb->pipe);
+	int			ret;
+
+	dev_dbg(musb->controller, "urb=%p, dev%d ep%d%s\n", urb,
+			usb_pipedevice(urb->pipe),
+			usb_pipeendpoint(urb->pipe),
+			is_in ? "in" : "out");
+
+	spin_lock_irqsave(&musb->lock, flags);
+	ret = usb_hcd_check_unlink_urb(hcd, urb, status);
+	if (ret)
+		goto done;
+
+	qh = urb->hcpriv;
+	if (!qh)
+		goto done;
+
+	/*
+	 * Any URB not actively programmed into endpoint hardware can be
+	 * immediately given back; that's any URB not at the head of an
+	 * endpoint queue, unless someday we get real DMA queues.  And even
+	 * if it's at the head, it might not be known to the hardware...
+	 *
+	 * Otherwise abort current transfer, pending DMA, etc.; urb->status
+	 * has already been updated.  This is a synchronous abort; it'd be
+	 * OK to hold off until after some IRQ, though.
+	 *
+	 * NOTE: qh is invalid unless !list_empty(&hep->urb_list)
+	 */
+	if (!qh->is_ready
+			|| urb->urb_list.prev != &qh->hep->urb_list
+			|| musb_ep_get_qh(qh->hw_ep, is_in) != qh) {
+		int	ready = qh->is_ready;
+
+		qh->is_ready = 0;
+		musb_giveback(musb, urb, 0);
+		qh->is_ready = ready;
+
+		/* If nothing else (usually musb_giveback) is using it
+		 * and its URB list has emptied, recycle this qh.
+		 */
+		if (ready && list_empty(&qh->hep->urb_list)) {
+			qh->hep->hcpriv = NULL;
+			list_del(&qh->ring);
+			kfree(qh);
+		}
+	} else
+		ret = musb_cleanup_urb(urb, qh);
+done:
+	spin_unlock_irqrestore(&musb->lock, flags);
+	return ret;
+}
+
+/* disable an endpoint */
+static void
+musb_h_disable(struct usb_hcd *hcd, struct usb_host_endpoint *hep)
+{
+	u8			is_in = hep->desc.bEndpointAddress & USB_DIR_IN;
+	unsigned long		flags;
+	struct musb		*musb = hcd_to_musb(hcd);
+	struct musb_qh		*qh;
+	struct urb		*urb;
+
+	spin_lock_irqsave(&musb->lock, flags);
+
+	qh = hep->hcpriv;
+	if (qh == NULL)
+		goto exit;
+
+	/* NOTE: qh is invalid unless !list_empty(&hep->urb_list) */
+
+	/* Kick the first URB off the hardware, if needed */
+	qh->is_ready = 0;
+	if (musb_ep_get_qh(qh->hw_ep, is_in) == qh) {
+		urb = next_urb(qh);
+
+		/* make software (then hardware) stop ASAP */
+		if (!urb->unlinked)
+			urb->status = -ESHUTDOWN;
+
+		/* cleanup */
+		musb_cleanup_urb(urb, qh);
+
+		/* Then nuke all the others ... and advance the
+		 * queue on hw_ep (e.g. bulk ring) when we're done.
+		 */
+		while (!list_empty(&hep->urb_list)) {
+			urb = next_urb(qh);
+			urb->status = -ESHUTDOWN;
+			musb_advance_schedule(musb, urb, qh->hw_ep, is_in);
+		}
+	} else {
+		/* Just empty the queue; the hardware is busy with
+		 * other transfers, and since !qh->is_ready nothing
+		 * will activate any of these as it advances.
+		 */
+		while (!list_empty(&hep->urb_list))
+			musb_giveback(musb, next_urb(qh), -ESHUTDOWN);
+
+		hep->hcpriv = NULL;
+		list_del(&qh->ring);
+		kfree(qh);
+	}
+exit:
+	spin_unlock_irqrestore(&musb->lock, flags);
+}
+
+static int musb_h_get_frame_number(struct usb_hcd *hcd)
+{
+	struct musb	*musb = hcd_to_musb(hcd);
+
+	return musb_readw(musb->mregs, MUSB_FRAME);
+}
+
+static int musb_h_start(struct usb_hcd *hcd)
+{
+	struct musb	*musb = hcd_to_musb(hcd);
+
+	/* NOTE: musb_start() is called when the hub driver turns
+	 * on port power, or when (OTG) peripheral starts.
+	 */
+	hcd->state = HC_STATE_RUNNING;
+	musb->port1_status = 0;
+	return 0;
+}
+
+static void musb_h_stop(struct usb_hcd *hcd)
+{
+	musb_stop(hcd_to_musb(hcd));
+	hcd->state = HC_STATE_HALT;
+}
+
+static int musb_bus_suspend(struct usb_hcd *hcd)
+{
+	struct musb	*musb = hcd_to_musb(hcd);
+	u8		devctl;
+
+	if (!is_host_active(musb))
+		return 0;
+
+	switch (musb->xceiv->state) {
+	case OTG_STATE_A_SUSPEND:
+		return 0;
+	case OTG_STATE_A_WAIT_VRISE:
+		/* ID could be grounded even if there's no device
+		 * on the other end of the cable.  NOTE that the
+		 * A_WAIT_VRISE timers are messy with MUSB...
+		 */
+		devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
+		if ((devctl & MUSB_DEVCTL_VBUS) == MUSB_DEVCTL_VBUS)
+			musb->xceiv->state = OTG_STATE_A_WAIT_BCON;
+		break;
+	default:
+		break;
+	}
+
+	if (musb->is_active) {
+		WARNING("trying to suspend as %s while active\n",
+				otg_state_string(musb->xceiv->state));
+		return -EBUSY;
+	} else
+		return 0;
+}
+
+static int musb_bus_resume(struct usb_hcd *hcd)
+{
+	/* resuming child port does the work */
+	return 0;
+}
+
+const struct hc_driver musb_hc_driver = {
+	.description		= "musb-hcd",
+	.product_desc		= "MUSB HDRC host driver",
+	.hcd_priv_size		= sizeof(struct musb),
+	.flags			= HCD_USB2 | HCD_MEMORY,
+
+	/* not using irq handler or reset hooks from usbcore, since
+	 * those must be shared with peripheral code for OTG configs
+	 */
+
+	.start			= musb_h_start,
+	.stop			= musb_h_stop,
+
+	.get_frame_number	= musb_h_get_frame_number,
+
+	.urb_enqueue		= musb_urb_enqueue,
+	.urb_dequeue		= musb_urb_dequeue,
+	.endpoint_disable	= musb_h_disable,
+
+	.hub_status_data	= musb_hub_status_data,
+	.hub_control		= musb_hub_control,
+	.bus_suspend		= musb_bus_suspend,
+	.bus_resume		= musb_bus_resume,
+	/* .start_port_reset	= NULL, */
+	/* .hub_irq_enable	= NULL, */
+};
+#endif