path: root/drivers/usb/host/ehci-q.c

/*
 * Copyright (C) 2001-2004 by David Brownell
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/* this file is part of ehci-hcd.c */

/*-------------------------------------------------------------------------*/

/*
 * EHCI hardware queue manipulation ... the core.  QH/QTD manipulation.
 *
 * Control, bulk, and interrupt traffic all use "qh" lists.  They list "qtd"
 * entries describing USB transactions, max 16-20kB/entry (with 4kB-aligned
 * buffers needed for the larger number).  We use one QH per endpoint, queue
 * multiple urbs (all three types) per endpoint.  URBs may need several qtds.
 *
 * ISO traffic uses "ISO TD" (itd, and sitd) records, and (along with
 * interrupts) needs careful scheduling.  Performance improvements can be
 * an ongoing challenge.  That's in "ehci-sched.c".
 *
 * USB 1.1 devices are handled (a) by "companion" OHCI or UHCI root hubs,
 * or otherwise through transaction translators (TTs) in USB 2.0 hubs using
 * (b) special fields in qh entries or (c) split iso entries.  TTs will
 * buffer low/full speed data so the host collects it at high speed.
 */

/*-------------------------------------------------------------------------*/

/* fill a qtd, returning how much of the buffer we were able to queue up */

static int
qtd_fill(struct ehci_hcd *ehci, struct ehci_qtd *qtd, dma_addr_t buf,
		  size_t len, int token, int maxpacket)
{
	int	i, count;
	u64	addr = buf;

	/* one buffer entry per 4K ... first might be short or unaligned */
	qtd->hw_buf[0] = cpu_to_hc32(ehci, (u32)addr);
	qtd->hw_buf_hi[0] = cpu_to_hc32(ehci, (u32)(addr >> 32));
	count = 0x1000 - (buf & 0x0fff);	/* rest of that page */
	if (likely (len < count))		/* ... iff needed */
		count = len;
	else {
		buf +=  0x1000;
		buf &= ~0x0fff;

		/* per-qtd limit: from 16K to 20K (best alignment) */
		for (i = 1; count < len && i < 5; i++) {
			addr = buf;
			qtd->hw_buf[i] = cpu_to_hc32(ehci, (u32)addr);
			qtd->hw_buf_hi[i] = cpu_to_hc32(ehci,
					(u32)(addr >> 32));
			buf += 0x1000;
			if ((count + 0x1000) < len)
				count += 0x1000;
			else
				count = len;
		}

		/* short packets may only terminate transfers */
		if (count != len)
			count -= (count % maxpacket);
	}
	qtd->hw_token = cpu_to_hc32(ehci, (count << 16) | token);
	qtd->length = count;

	return count;
}

/*-------------------------------------------------------------------------*/

static inline void
qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
{
	struct ehci_qh_hw *hw = qh->hw;

	/* writes to an active overlay are unsafe */
	WARN_ON(qh->qh_state != QH_STATE_IDLE);

	hw->hw_qtd_next = QTD_NEXT(ehci, qtd->qtd_dma);
	hw->hw_alt_next = EHCI_LIST_END(ehci);

	/* Except for control endpoints, we make hardware maintain data
	 * toggle (like OHCI) ... here (re)initialize the toggle in the QH,
	 * and set the pseudo-toggle in udev. Only usb_clear_halt() will
	 * ever clear it.
	 */
	if (!(hw->hw_info1 & cpu_to_hc32(ehci, QH_TOGGLE_CTL))) {
		unsigned	is_out, epnum;

		is_out = qh->is_out;
		epnum = (hc32_to_cpup(ehci, &hw->hw_info1) >> 8) & 0x0f;
		if (unlikely(!usb_gettoggle(qh->ps.udev, epnum, is_out))) {
			hw->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
			usb_settoggle(qh->ps.udev, epnum, is_out, 1);
		}
	}

	hw->hw_token &= cpu_to_hc32(ehci, QTD_TOGGLE | QTD_STS_PING);
}

/* if it weren't for a common silicon quirk (writing the dummy into the qh
 * overlay, so qh->hw_token wrongly becomes inactive/halted), only fault
 * recovery (including urb dequeue) would need software changes to a QH...
 */
static void
qh_refresh (struct ehci_hcd *ehci, struct ehci_qh *qh)
{
	struct ehci_qtd *qtd;

	qtd = list_entry(qh->qtd_list.next, struct ehci_qtd, qtd_list);

	/*
	 * first qtd may already be partially processed.
	 * If we come here during unlink, the QH overlay region
	 * might have reference to the just unlinked qtd. The
	 * qtd is updated in qh_completions(). Update the QH
	 * overlay here.
	 */
	if (qh->hw->hw_token & ACTIVE_BIT(ehci)) {
		qh->hw->hw_qtd_next = qtd->hw_next;
		if (qh->should_be_inactive)
			ehci_warn(ehci, "qh %p should be inactive!\n", qh);
	} else {
		qh_update(ehci, qh, qtd);
	}
	qh->should_be_inactive = 0;
}

/*-------------------------------------------------------------------------*/

static void qh_link_async(struct ehci_hcd *ehci, struct ehci_qh *qh);

static void ehci_clear_tt_buffer_complete(struct usb_hcd *hcd,
		struct usb_host_endpoint *ep)
{
	struct ehci_hcd		*ehci = hcd_to_ehci(hcd);
	struct ehci_qh		*qh = ep->hcpriv;
	unsigned long		flags;

	spin_lock_irqsave(&ehci->lock, flags);
	qh->clearing_tt = 0;
	if (qh->qh_state == QH_STATE_IDLE && !list_empty(&qh->qtd_list)
			&& ehci->rh_state == EHCI_RH_RUNNING)
		qh_link_async(ehci, qh);
	spin_unlock_irqrestore(&ehci->lock, flags);
}

static void ehci_clear_tt_buffer(struct ehci_hcd *ehci, struct ehci_qh *qh,
		struct urb *urb, u32 token)
{

	/* If an async split transaction gets an error or is unlinked,
	 * the TT buffer may be left in an indeterminate state.  We
	 * have to clear the TT buffer.
	 *
	 * Note: this routine is never called for Isochronous transfers.
	 */
	if (urb->dev->tt && !usb_pipeint(urb->pipe) && !qh->clearing_tt) {
#ifdef CONFIG_DYNAMIC_DEBUG
		struct usb_device *tt = urb->dev->tt->hub;
		dev_dbg(&tt->dev,
			"clear tt buffer port %d, a%d ep%d t%08x\n",
			urb->dev->ttport, urb->dev->devnum,
			usb_pipeendpoint(urb->pipe), token);
#endif /* CONFIG_DYNAMIC_DEBUG */
		if (!ehci_is_TDI(ehci)
				|| urb->dev->tt->hub !=
				   ehci_to_hcd(ehci)->self.root_hub) {
			if (usb_hub_clear_tt_buffer(urb) == 0)
				qh->clearing_tt = 1;
		} else {

			/* REVISIT ARC-derived cores don't clear the root
			 * hub TT buffer in this way...
			 */
		}
	}
}

static int qtd_copy_status (
	struct ehci_hcd *ehci,
	struct urb *urb,
	size_t length,
	u32 token
)
{
	int	status = -EINPROGRESS;

	/* count IN/OUT bytes, not SETUP (even short packets) */
	if (likely (QTD_PID (token) != 2))
		urb->actual_length += length - QTD_LENGTH (token);

	/* don't modify error codes */
	if (unlikely(urb->unlinked))
		return status;

	/* force cleanup after short read; not always an error */
	if (unlikely (IS_SHORT_READ (token)))
		status = -EREMOTEIO;

	/* serious "can't proceed" faults reported by the hardware */
	if (token & QTD_STS_HALT) {
		if (token & Q