[PATCH 5/9] Add Synopsys DesignWare HS USB OTG Controller driver.

[Fushen Chen <fchen@apm.com>]

Implements DWC OTG USB Host Controller Driver (HCD) interrupt
service routine.

Signed-off-by: Fushen Chen <fchen@apm.com>
Signed-off-by: Mark Miesfeld <mmiesfeld@apm.com>
---
 drivers/usb/otg/dwc_otg_hcd_intr.c | 1446 ++++++++++++++++++++++++++++++++++++
 1 files changed, 1446 insertions(+), 0 deletions(-)
 create mode 100644 drivers/usb/otg/dwc_otg_hcd_intr.c

diff --git a/drivers/usb/otg/dwc_otg_hcd_intr.c b/drivers/usb/otg/dwc_otg_hcd_intr.c
new file mode 100644
index 0000000..dc00184
--- /dev/null
+++ b/drivers/usb/otg/dwc_otg_hcd_intr.c
@@ -0,0 +1,1446 @@
+/*
+ * DesignWare HS OTG controller driver
+ *
+ * Author: Mark Miesfeld <mmiesfeld@apm.com>
+ *
+ * Based on versions provided by AMCC and Synopsis which are:
+ *	Copyright (C) 2009-2010 AppliedMicro(www.apm.com)
+ *
+ * Synopsys HS OTG Linux Software Driver and documentation (hereinafter,
+ * "Software") is an Unsupported proprietary work of Synopsys, Inc. unless
+ * otherwise expressly agreed to in writing between Synopsys and you.
+ *
+ * The Software IS NOT an item of Licensed Software or Licensed Product under
+ * any End User Software License Agreement or Agreement for Licensed Product
+ * with Synopsys or any supplement thereto. You are permitted to use and
+ * redistribute this Software in source and binary forms, with or without
+ * modification, provided that redistributions of source code must retain this
+ * notice. You may not view, use, disclose, copy or distribute this file or
+ * any information contained herein except pursuant to this license grant from
+ * Synopsys. If you do not agree with this notice, including the disclaimer
+ * below, then you are not authorized to use the Software.
+ *
+ * THIS SOFTWARE IS BEING DISTRIBUTED BY SYNOPSYS SOLELY ON AN "AS IS" BASIS
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE HEREBY DISCLAIMED. IN NO EVENT SHALL SYNOPSYS 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.
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "dwc_otg_driver.h"
+#include "dwc_otg_hcd.h"
+#include "dwc_otg_regs.h"
+
+/* This file contains the implementation of the HCD Interrupt handlers.	*/
+
+
+
+/**
+ * Handles the start-of-frame interrupt in host mode. Non-periodic
+ * transactions may be queued to the DWC_otg controller for the current
+ * (micro)frame. Periodic transactions may be queued to the controller for the
+ * next (micro)frame.
+ */
+static int dwc_otg_hcd_handle_sof_intr(struct dwc_hcd *hcd)
+{
+	union hfnum_data hfnum;
+	struct list_head *qh_entry;
+	struct dwc_qh *qh;
+	enum dwc_transaction_type tr_type;
+	union gintsts_data gintsts = {.d32 = 0};
+
+	hfnum.d32 =
+		dwc_read_reg32(&hcd->core_if->host_if->host_global_regs->hfnum);
+
+	hcd->frame_number = hfnum.b.frnum;
+
+	/* Determine whether any periodic QHs should be executed. */
+	qh_entry = hcd->periodic_sched_inactive.next;
+	while (qh_entry != &hcd->periodic_sched_inactive) {
+		qh = list_entry(qh_entry, struct dwc_qh, qh_list_entry);
+		qh_entry = qh_entry->next;
+
+		/*
+		 * If needed, move QH to the ready list to be executed next
+		 * (micro)frame.
+		 */
+		if (dwc_frame_num_le(qh->sched_frame, hcd->frame_number))
+			list_move(&qh->qh_list_entry,
+				&hcd->periodic_sched_ready);
+	}
+
+	tr_type = dwc_otg_hcd_select_transactions(hcd);
+	if (tr_type != DWC_OTG_TRANSACTION_NONE)
+		dwc_otg_hcd_queue_transactions(hcd, tr_type);
+
+	/* Clear interrupt */
+	gintsts.b.sofintr = 1;
+	dwc_write_reg32(gintsts_reg(hcd), gintsts.d32);
+	return 1;
+}
+
+/**
+ * Handles the Rx Status Queue Level Interrupt, which indicates that there is at
+ * least one packet in the Rx FIFO.  The packets are moved from the FIFO to
+ * memory if the DWC_otg controller is operating in Slave mode.
+ */
+static int dwc_otg_hcd_handle_rx_status_q_level_intr(struct dwc_hcd *hcd)
+{
+	union host_grxsts_data grxsts;
+	struct dwc_hc *hc = NULL;
+
+	grxsts.d32 = dwc_read_reg32(&hcd->core_if->core_global_regs->grxstsp);
+	hc = hcd->hc_ptr_array[grxsts.b.chnum];
+
+	/* Packet Status */
+	switch (grxsts.b.pktsts) {
+	case DWC_GRXSTS_PKTSTS_IN:
+		/* Read the data into the host buffer. */
+		if (grxsts.b.bcnt > 0) {
+			dwc_otg_read_packet(hcd->core_if, hc->xfer_buff,
+						grxsts.b.bcnt);
+
+			/* Update the HC fields for the next packet received. */
+			hc->xfer_count += grxsts.b.bcnt;
+			hc->xfer_buff += grxsts.b.bcnt;
+		}
+	case DWC_GRXSTS_PKTSTS_IN_XFER_COMP:
+	case DWC_GRXSTS_PKTSTS_DATA_TOGGLE_ERR:
+	case DWC_GRXSTS_PKTSTS_CH_HALTED:
+		/* Handled in interrupt, just ignore data */
+		break;
+	default:
+		printk(KERN_ERR "RX_STS_Q Interrupt: Unknown status %d\n",
+					grxsts.b.pktsts);
+		break;
+	}
+	return 1;
+}
+
+/**
+ * This interrupt occurs when the non-periodic Tx FIFO is half-empty. More
+ * data packets may be written to the FIFO for OUT transfers. More requests
+ * may be written to the non-periodic request queue for IN transfers. This
+ * interrupt is enabled only in Slave mode.
+ */
+static int dwc_otg_hcd_handle_np_tx_fifo_empty_intr(struct dwc_hcd *hcd)
+{
+	dwc_otg_hcd_queue_transactions(hcd, DWC_OTG_TRANSACTION_NON_PERIODIC);
+	return 1;
+}
+
+/**
+ * This interrupt occurs when the periodic Tx FIFO is half-empty. More data
+ * packets may be written to the FIFO for OUT transfers. More requests may be
+ * written to the periodic request queue for IN transfers. This interrupt is
+ * enabled only in Slave mode.
+ */
+static int dwc_otg_hcd_handle_perio_tx_fifo_empty_intr(struct dwc_hcd *hcd)
+{
+	dwc_otg_hcd_queue_transactions(hcd, DWC_OTG_TRANSACTION_PERIODIC);
+	return 1;
+}
+
+/**
+ * When the port changes to enabled it may be necessary to adjust the phy clock
+ * speed.
+ */
+static int adjusted_phy_clock_speed(struct dwc_hcd *hcd, union hprt0_data hprt0)
+{
+	int adjusted = 0;
+	union gusbcfg_data usbcfg;
+	struct core_params *params = hcd->core_if->core_params;
+	struct core_global_regs *g_regs = hcd->core_if->core_global_regs;
+	struct host_global_regs *h_regs =
+		hcd->core_if->host_if->host_global_regs;
+
+	usbcfg.d32 = dwc_read_reg32(&g_regs->gusbcfg);
+
+	if (hprt0.b.prtspd == DWC_HPRT0_PRTSPD_LOW_SPEED ||
+		hprt0.b.prtspd == DWC_HPRT0_PRTSPD_FULL_SPEED) {
+		/* Low power */
+		union hcfg_data hcfg;
+
+		if (usbcfg.b.phylpwrclksel == 0) {
+			/* Set PHY low power clock select for FS/LS devices */
+			usbcfg.b.phylpwrclksel = 1;
+			dwc_write_reg32(&g_regs->gusbcfg, usbcfg.d32);
+			adjusted = 1;
+		}
+
+		hcfg.d32 = dwc_read_reg32(&h_regs->hcfg);
+		if (hprt0.b.prtspd == DWC_HPRT0_PRTSPD_LOW_SPEED &&
+				params->host_ls_low_power_phy_clk ==
+				DWC_HOST_LS_LOW_POWER_PHY_CLK_PARAM_6MHZ) {
+			/* 6 MHZ, check for 6 MHZ clock select */
+			if (hcfg.b.fslspclksel != DWC_HCFG_6_MHZ) {
+				hcfg.b.fslspclksel = DWC_HCFG_6_MHZ;
+				dwc_write_reg32(&h_regs->hcfg, hcfg.d32);
+				adjusted = 1;
+			}
+		} else if (hcfg.b.fslspclksel != DWC_HCFG_48_MHZ) {
+			/* 48 MHZ and clock select is not 48 MHZ */
+			hcfg.b.fslspclksel = DWC_HCFG_48_MHZ;
+			dwc_write_reg32(&h_regs->hcfg, hcfg.d32);
+			adjusted = 1;
+		}
+	} else if (usbcfg.b.phylpwrclksel == 1) {
+		usbcfg.b.phylpwrclksel = 0;
+		dwc_write_reg32(&g_regs->gusbcfg, usbcfg.d32);
+		adjusted = 1;
+	}
+	if (adjusted)
+		schedule_work(&hcd->usb_port_reset);
+
+	return adjusted;
+}
+
+/**
+ * Helper function to handle the port enable changed interrupt when the port
+ * becomes enabled.  Checks if we need to adjust the PHY clock speed for low
+ * power and  adjusts it if needed.
+ */
+static void port_enabled(struct dwc_hcd *hcd, union hprt0_data hprt0)
+{
+	if (hcd->core_if->core_params->host_support_fs_ls_low_power)
+		if (!adjusted_phy_clock_speed(hcd, hprt0))
+			hcd->flags.b.port_reset_change = 1;
+}
+
+/**
+ * There are multiple conditions that can cause a port interrupt. This function
+ * determines which interrupt conditions have occurred and handles them
+ * appropriately.
+ */
+static int dwc_otg_hcd_handle_port_intr(struct dwc_hcd *hcd)
+{
+	int retval = 0;
+	union hprt0_data hprt0;
+	union hprt0_data hprt0_modify;
+	hprt0.d32 = dwc_read_reg32(hcd->core_if->host_if->hprt0);
+	hprt0_modify.d32 = dwc_read_reg32(hcd->core_if->host_if->hprt0);
+
+	/*
+	 * Clear appropriate bits in HPRT0 to clear the interrupt bit in
+	 * GINTSTS
+	 */
+	hprt0_modify.b.prtena = 0;
+	hprt0_modify.b.prtconndet = 0;
+	hprt0_modify.b.prtenchng = 0;
+	hprt0_modify.b.prtovrcurrchng = 0;
+
+	/* Port connect detected interrupt */
+	if (hprt0.b.prtconndet) {
+		/* Set the status flags and clear interrupt*/
+		hcd->flags.b.port_connect_status_change = 1;
+		hcd->flags.b.port_connect_status = 1;
+		hprt0_modify.b.prtconndet = 1;
+
+		/* B-Device has connected, Delete the connection timer. */
+		del_timer_sync(&hcd->conn_timer);
+
+		/*
+		 * The Hub driver asserts a reset when it sees port connect
+		 * status change flag
+		 */
+		retval |= 1;
+	}
+
+	/* Port enable changed interrupt */
+	if (hprt0.b.prtenchng) {
+		/* Set the internal flag if the port was disabled */
+		if (hprt0.b.prtena)
+			port_enabled(hcd, hprt0);
+		else
+			hcd->flags.b.port_enable_change = 1;
+
+		/* Clear the interrupt */
+		hprt0_modify.b.prtenchng = 1;
+		retval |= 1;
+	}
+
+	/* Overcurrent change interrupt	*/
+	if (hprt0.b.prtovrcurrchng) {
+		hcd->flags.b.port_over_current_change = 1;
+		hprt0_modify.b.prtovrcurrchng = 1;
+		retval |= 1;
+	}
+
+	/* Clear the port interrupts */
+	dwc_write_reg32(hcd->core_if->host_if->hprt0, hprt0_modify.d32);
+	return retval;
+}
+
+/**
+ * Gets the actual length of a transfer after the transfer halts. halt_status
+ * holds the reason for the halt.
+ *
+ * For IN transfers where halt_status is DWC_OTG_HC_XFER_COMPLETE, _short_read
+ * is set to 1 upon return if less than the requested number of bytes were
+ * transferred. Otherwise, _short_read is set to 0 upon return. _short_read may
+ * also be NULL on entry, in which case it remains unchanged.
+ */
+static u32 get_actual_xfer_length(struct dwc_hc *hc, struct dwc_hc_regs *regs,
+			struct dwc_qtd *qtd, enum dwc_halt_status halt_status,
+			int *_short_read)
+{
+	union hctsiz_data hctsiz;
+	u32 length;
+
+	if (_short_read)
+		*_short_read = 0;
+
+	hctsiz.d32 = dwc_read_reg32(&regs->hctsiz);
+	if (halt_status == DWC_OTG_HC_XFER_COMPLETE) {
+		if (hc->ep_is_in) {
+			length = hc->xfer_len - hctsiz.b.xfersize;
+			if (_short_read)
+				*_short_read = (hctsiz.b.xfersize != 0);
+		} else if (hc->qh->do_split) {
+			length = qtd->ssplit_out_xfer_count;
+		} else {
+			length = hc->xfer_len;
+		}
+	} else {
+		/*
+		 * Must use the hctsiz.pktcnt field to determine how much data
+		 * has been transferred. This field reflects the number of
+		 * packets that have been transferred via the USB. This is
+		 * always an integral number of packets if the transfer was
+		 * halted before its normal completion. (Can't use the
+		 * hctsiz.xfersize field because that reflects the number of
+		 * bytes transferred via the AHB, not the USB).
+		 */
+		length = (hc->start_pkt_count - hctsiz.b.pktcnt) *
+				hc->max_packet;
+	}
+	return length;
+}
+
+/**
+ * Updates the state of the URB after a Transfer Complete interrupt on the
+ * host channel. Updates the actual_length field of the URB based on the
+ * number of bytes transferred via the host channel. Sets the URB status
+ * if the data transfer is finished.
+ */
+static int update_urb_state_xfer_comp(struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct urb *urb,
+			struct dwc_qtd *qtd, int *status)
+{
+	int xfer_done = 0;
+	int short_read = 0;
+
+	urb->actual_length += get_actual_xfer_length(hc, regs, qtd,
+			DWC_OTG_HC_XFER_COMPLETE, &short_read);
+
+	if (short_read || urb->actual_length == urb->transfer_buffer_length) {
+		xfer_done = 1;
+		if (short_read && (urb->transfer_flags & URB_SHORT_NOT_OK))
+			*status = -EREMOTEIO;
+		else
+			*status = 0;
+	}
+	return xfer_done;
+}
+
+/*
+ * Save the starting data toggle for the next transfer. The data toggle is
+ * saved in the QH for non-control transfers and it's saved in the QTD for
+ * control transfers.
+ */
+static void save_data_toggle(struct dwc_hc *hc, struct dwc_hc_regs *regs,
+				struct dwc_qtd *qtd)
+{
+	union hctsiz_data hctsiz;
+	hctsiz.d32 = dwc_read_reg32(&regs->hctsiz);
+
+	if (hc->ep_type != DWC_OTG_EP_TYPE_CONTROL) {
+		struct dwc_qh *qh = hc->qh;
+		if (hctsiz.b.pid == DWC_HCTSIZ_DATA0)
+			qh->data_toggle = DWC_OTG_HC_PID_DATA0;
+		else
+			qh->data_toggle = DWC_OTG_HC_PID_DATA1;
+	} else {
+		if (hctsiz.b.pid == DWC_HCTSIZ_DATA0)
+			qtd->data_toggle = DWC_OTG_HC_PID_DATA0;
+		else
+			qtd->data_toggle = DWC_OTG_HC_PID_DATA1;
+	}
+}
+
+/**
+ * Frees the first QTD in the QH's list if free_qtd is 1. For non-periodic
+ * QHs, removes the QH from the active non-periodic schedule. If any QTDs are
+ * still linked to the QH, the QH is added to the end of the inactive
+ * non-periodic schedule. For periodic QHs, removes the QH from the periodic
+ * schedule if no more QTDs are linked to the QH.
+ */
+static void deactivate_qh(struct dwc_hcd *hcd, struct dwc_qh *qh, int free_qtd)
+{
+	int continue_split = 0;
+	struct dwc_qtd *qtd;
+
+	qtd = list_entry(qh->qtd_list.next, struct dwc_qtd, qtd_list_entry);
+	if (qtd->complete_split)
+		continue_split = 1;
+	else if (qtd->isoc_split_pos == DWC_HCSPLIT_XACTPOS_MID ||
+			qtd->isoc_split_pos == DWC_HCSPLIT_XACTPOS_END)
+		continue_split = 1;
+
+	if (free_qtd) {
+		dwc_otg_hcd_qtd_remove_and_free(qtd);
+		continue_split = 0;
+	}
+
+	qh->channel = NULL;
+	qh->qtd_in_process = NULL;
+	dwc_otg_hcd_qh_deactivate(hcd, qh, continue_split);
+}
+
+/**
+ * Updates the state of an Isochronous URB when the transfer is stopped for
+ * any reason. The fields of the current entry in the frame descriptor array
+ * are set based on the transfer state and the input status. Completes the
+ * Isochronous URB if all the URB frames have been completed.
+ */
+static enum dwc_halt_status update_isoc_urb_state(struct dwc_hcd *hcd,
+		struct dwc_hc *hc, struct dwc_hc_regs *regs,
+		struct dwc_qtd *qtd, enum dwc_halt_status status)
+{
+	struct urb *urb = qtd->urb;
+	enum dwc_halt_status ret_val = status;
+	struct usb_iso_packet_descriptor *frame_desc;
+	frame_desc = &urb->iso_frame_desc[qtd->isoc_frame_index];
+
+	switch (status) {
+	case DWC_OTG_HC_XFER_COMPLETE:
+		frame_desc->status = 0;
+		frame_desc->actual_length =
+			get_actual_xfer_length(hc, regs, qtd, status, NULL);
+		break;
+	case DWC_OTG_HC_XFER_FRAME_OVERRUN:
+		urb->error_count++;
+		if (hc->ep_is_in)
+			frame_desc->status = -ENOSR;
+		else
+			frame_desc->status = -ECOMM;
+
+		frame_desc->actual_length = 0;
+		break;
+	case DWC_OTG_HC_XFER_BABBLE_ERR:
+		/* Don't need to update actual_length in this case. */
+		urb->error_count++;
+		frame_desc->status = -EOVERFLOW;
+		break;
+	case DWC_OTG_HC_XFER_XACT_ERR:
+		urb->error_count++;
+		frame_desc->status = -EPROTO;
+		frame_desc->actual_length =
+			get_actual_xfer_length(hc, regs, qtd, status, NULL);
+	default:
+		printk(KERN_ERR "%s: Unhandled halt_status (%d)\n", __func__,
+				status);
+		BUG();
+		break;
+	}
+
+	if (++qtd->isoc_frame_index == urb->number_of_packets) {
+		/*
+		 * urb->status is not used for isoc transfers.
+		 * The individual frame_desc statuses are used instead.
+		 */
+		dwc_otg_hcd_complete_urb(hcd, urb, 0);
+		ret_val = DWC_OTG_HC_XFER_URB_COMPLETE;
+	} else {
+		ret_val = DWC_OTG_HC_XFER_COMPLETE;
+	}
+	return ret_val;
+}
+
+/**
+ * Releases a host channel for use by other transfers. Attempts to select and
+ * queue more transactions since at least one host channel is available.
+ */
+static void release_channel(struct dwc_hcd *hcd, struct dwc_hc *hc,
+				struct dwc_qtd *qtd,
+				enum dwc_halt_status halt_status)  {
+	enum dwc_transaction_type tr_type;
+	int free_qtd;
+
+	switch (halt_status) {
+	case DWC_OTG_HC_XFER_URB_COMPLETE:
+		free_qtd = 1;
+		break;
+
+	case DWC_OTG_HC_XFER_AHB_ERR:
+	case DWC_OTG_HC_XFER_STALL:
+	case DWC_OTG_HC_XFER_BABBLE_ERR:
+		free_qtd = 1;
+		break;
+	case DWC_OTG_HC_XFER_XACT_ERR:
+		if (qtd->error_count >= 3) {
+			free_qtd = 1;
+			dwc_otg_hcd_complete_urb(hcd, qtd->urb, -EPROTO);
+		} else {
+			free_qtd = 0;
+		}
+		break;
+	case DWC_OTG_HC_XFER_URB_DEQUEUE:
+		/*
+		 * The QTD has already been removed and the QH has been
+		 * deactivated. Don't want to do anything except release the
+		 * host channel and try to queue more transfers.
+		 */
+		goto cleanup;
+	case DWC_OTG_HC_XFER_NO_HALT_STATUS:
+		printk(KERN_ERR "%s: No halt_status, channel %d\n", __func__,
+				hc->hc_num);
+		free_qtd = 0;
+		break;
+	default:
+		free_qtd = 0;
+		break;
+	}
+	deactivate_qh(hcd, hc->qh, free_qtd);
+
+cleanup:
+	/*
+	 * Release the host channel for use by other transfers. The cleanup
+	 * function clears the channel interrupt enables and conditions, so
+	 * there's no need to clear the Channel Halted interrupt separately.
+	 */
+	dwc_otg_hc_cleanup(hcd->core_if, hc);
+	list_add_tail(&hc->hc_list_entry, &hcd->free_hc_list);
+
+	switch (hc->ep_type) {
+	case DWC_OTG_EP_TYPE_CONTROL:
+	case DWC_OTG_EP_TYPE_BULK:
+		hcd->non_periodic_channels--;
+		break;
+	default:
+		/*
+		 * Don't release reservations for periodic channels here.
+		 * That's done when a periodic transfer is descheduled (i.e.
+		 * when the QH is removed from the periodic schedule).
+		 */
+		break;
+	}
+
+	/* Try to queue more transfers now that there's a free channel. */
+	tr_type = dwc_otg_hcd_select_transactions(hcd);
+	if (tr_type != DWC_OTG_TRANSACTION_NONE)
+		dwc_otg_hcd_queue_transactions(hcd, tr_type);
+}
+
+/**
+ * Halts a host channel. If the channel cannot be halted immediately because
+ * the request queue is full, this function ensures that the FIFO empty
+ * interrupt for the appropriate queue is enabled so that the halt request can
+ * be queued when there is space in the request queue.
+ *
+ * This function may also be called in DMA mode. In that case, the channel is
+ * simply released since the core always halts the channel automatically in
+ * DMA mode.
+ */
+static void halt_channel(struct dwc_hcd *hcd, struct dwc_hc *hc,
+	 struct dwc_qtd *qtd, enum dwc_halt_status halt_status)
+{
+	if (hcd->core_if->dma_enable) {
+		release_channel(hcd, hc, qtd, halt_status);
+		return;
+	}
+
+	/* Slave mode processing... */
+	dwc_otg_hc_halt(hcd->core_if, hc, halt_status);
+	if (hc->halt_on_queue) {
+		union gintmsk_data gintmsk = {.d32 = 0};
+
+		if (hc->ep_type == DWC_OTG_EP_TYPE_CONTROL ||
+				hc->ep_type == DWC_OTG_EP_TYPE_BULK) {
+			/*
+			 * Make sure the Non-periodic Tx FIFO empty interrupt
+			 * is enabled so that the non-periodic schedule will
+			 * be processed.
+			 */
+			gintmsk.b.nptxfempty = 1;
+			dwc_modify_reg32(gintmsk_reg(hcd), 0, gintmsk.d32);
+		} else {
+			/*
+			 * Move the QH from the periodic queued schedule to
+			 * the periodic assigned schedule. This allows the
+			 * halt to be queued when the periodic schedule is
+			 * processed.
+			 */
+			list_move(&hc->qh->qh_list_entry,
+				&hcd->periodic_sched_assigned);
+
+			/*
+			 * Make sure the Periodic Tx FIFO Empty interrupt is
+			 * enabled so that the periodic schedule will be
+			 * processed.
+			 */
+			gintmsk.b.ptxfempty = 1;
+			dwc_modify_reg32(gintmsk_reg(hcd), 0, gintmsk.d32);
+		}
+	}
+}
+
+/**
+ * Performs common cleanup for non-periodic transfers after a Transfer
+ * Complete interrupt. This function should be called after any endpoint type
+ * specific handling is finished to release the host channel.
+ */
+static void complete_non_periodic_xfer(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd,
+			enum dwc_halt_status halt_status)
+{
+	union hcint_data hcint;
+
+	qtd->error_count = 0;
+	hcint.d32 = dwc_read_reg32(&regs->hcint);
+	if (hcint.b.nyet) {
+		union hcint_data hcint_clear = { .d32 = 0};
+		hcint_clear.b.nyet = 1;
+
+		/*
+		 * Got a NYET on the last transaction of the transfer. This
+		 * means that the endpoint should be in the PING state at the
+		 * beginning of the next transfer.
+		 */
+		hc->qh->ping_state = 1;
+		dwc_write_reg32(&(regs->hcint), hcint_clear.d32);
+	}
+
+	/*
+	 * Always halt and release the host channel to make it available for
+	 * more transfers. There may still be more phases for a control
+	 * transfer or more data packets for a bulk transfer at this point,
+	 * but the host channel is still halted. A channel will be reassigned
+	 * to the transfer when the non-periodic schedule is processed after
+	 * the channel is released. This allows transactions to be queued
+	 * properly via dwc_otg_hcd_queue_transactions, which also enables the
+	 * Tx FIFO Empty interrupt if necessary.
+	 *
+	 * IN transfers in Slave mode require an explicit disable to
+	 * halt the channel. (In DMA mode, this call simply releases
+	 * the channel.)
+	 *
+	 * The channel is automatically disabled by the core for OUT
+	 * transfers in Slave mode.
+	 */
+	if (hc->ep_is_in)
+		halt_channel(hcd, hc, qtd, halt_status);
+	else
+		release_channel(hcd, hc, qtd, halt_status);
+}
+
+/**
+ * Performs common cleanup for periodic transfers after a Transfer Complete
+ * interrupt. This function should be called after any endpoint type specific
+ * handling is finished to release the host channel.
+ */
+static void complete_periodic_xfer(struct dwc_hcd *hcd, struct dwc_hc *hc,
+		struct dwc_hc_regs *regs, struct dwc_qtd *qtd,
+		enum dwc_halt_status halt_status)
+{
+	union hctsiz_data hctsiz;
+
+	hctsiz.d32 = dwc_read_reg32(&regs->hctsiz);
+	qtd->error_count = 0;
+
+	/*
+	 * For OUT transfers and 0 packet count, the Core halts the channel,
+	 * otherwise, Flush any outstanding requests from the Tx queue.
+	 */
+	if (!hc->ep_is_in || hctsiz.b.pktcnt == 0)
+		release_channel(hcd, hc, qtd, halt_status);
+	else
+		halt_channel(hcd, hc, qtd, halt_status);
+}
+
+/**
+ * Handles a host channel Transfer Complete interrupt. This handler may be
+ * called in either DMA mode or Slave mode.
+ */
+static int handle_hc_xfercomp_intr(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	int urb_xfer_done;
+	enum dwc_halt_status halt_status = DWC_OTG_HC_XFER_COMPLETE;
+	struct urb *urb = qtd->urb;
+	int pipe_type = usb_pipetype(urb->pipe);
+	int status = -EINPROGRESS;
+	union hcintmsk_data hcintmsk = {.d32 = 0};
+
+	/* Handle xfer complete on CSPLIT. */
+	if (hc->qh->do_split)
+		qtd->complete_split = 0;
+
+	/* Update the QTD and URB states. */
+	switch (pipe_type) {
+	case PIPE_CONTROL:
+		switch (qtd->control_phase) {
+		case DWC_OTG_CONTROL_SETUP:
+			if (urb->transfer_buffer_length > 0)
+				qtd->control_phase = DWC_OTG_CONTROL_DATA;
+			else
+				qtd->control_phase = DWC_OTG_CONTROL_STATUS;
+			halt_status = DWC_OTG_HC_XFER_COMPLETE;
+			break;
+		case DWC_OTG_CONTROL_DATA:
+			urb_xfer_done = update_urb_state_xfer_comp(hc, regs,
+							urb, qtd, &status);
+			if (urb_xfer_done)
+				qtd->control_phase = DWC_OTG_CONTROL_STATUS;
+			else
+				save_data_toggle(hc, regs, qtd);	
+			halt_status = DWC_OTG_HC_XFER_COMPLETE;
+			break;
+		case DWC_OTG_CONTROL_STATUS:
+			if (status == -EINPROGRESS)
+				status = 0;
+			dwc_otg_hcd_complete_urb(hcd, urb, status);
+			halt_status = DWC_OTG_HC_XFER_URB_COMPLETE;
+			break;
+		}
+		complete_non_periodic_xfer(hcd, hc, regs, qtd, halt_status);
+		break;
+	case PIPE_BULK:
+		urb_xfer_done = update_urb_state_xfer_comp(hc, regs, urb, qtd,
+								&status);
+		if (urb_xfer_done) {
+			dwc_otg_hcd_complete_urb(hcd, urb, status);
+			halt_status = DWC_OTG_HC_XFER_URB_COMPLETE;
+		} else {
+			halt_status = DWC_OTG_HC_XFER_COMPLETE;
+		}
+
+		save_data_toggle(hc, regs, qtd);
+		complete_non_periodic_xfer(hcd, hc, regs, qtd, halt_status);
+		break;
+	case PIPE_INTERRUPT:
+		update_urb_state_xfer_comp(hc, regs, urb, qtd, &status);
+
+		/*
+		 * Interrupt URB is done on the first transfer complete
+		 * interrupt.
+		 */
+		dwc_otg_hcd_complete_urb(hcd, urb, status);
+		save_data_toggle(hc, regs, qtd);
+		complete_periodic_xfer(hcd, hc, regs, qtd,
+			DWC_OTG_HC_XFER_URB_COMPLETE);
+		break;
+	case PIPE_ISOCHRONOUS:
+		if (qtd->isoc_split_pos == DWC_HCSPLIT_XACTPOS_ALL) {
+			halt_status = update_isoc_urb_state(hcd, hc, regs, qtd,
+					DWC_OTG_HC_XFER_COMPLETE);
+		}
+		complete_periodic_xfer(hcd, hc, regs, qtd, halt_status);
+		break;
+	}
+
+	/* disable xfercompl */
+	hcintmsk.b.xfercompl = 1;
+	dwc_modify_reg32(&regs->hcintmsk, hcintmsk.d32, 0);
+
+	return 1;
+}
+
+/**
+ * Handles a host channel STALL interrupt. This handler may be called in
+ * either DMA mode or Slave mode.
+ */
+static int handle_hc_stall_intr(struct dwc_hcd *hcd,	struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	struct urb *urb = qtd->urb;
+	int pipe_type = usb_pipetype(urb->pipe);
+	union hcintmsk_data hcintmsk = {.d32 = 0};
+
+	if (pipe_type == PIPE_CONTROL)
+		dwc_otg_hcd_complete_urb(hcd, qtd->urb, -EPIPE);
+
+	if (pipe_type == PIPE_BULK || pipe_type == PIPE_INTERRUPT) {
+		dwc_otg_hcd_complete_urb(hcd, qtd->urb, -EPIPE);
+		/*
+		 * USB protocol requires resetting the data toggle for bulk
+		 * and interrupt endpoints when a CLEAR_FEATURE(ENDPOINT_HALT)
+		 * setup command is issued to the endpoint. Anticipate the
+		 * CLEAR_FEATURE command since a STALL has occurred and reset
+		 * the data toggle now.
+		 */
+		hc->qh->data_toggle = 0;
+	}
+
+	halt_channel(hcd, hc, qtd, DWC_OTG_HC_XFER_STALL);
+	/* disable stall */
+	hcintmsk.b.stall = 1;
+	dwc_modify_reg32(&regs->hcintmsk, hcintmsk.d32, 0);
+
+	return 1;
+}
+
+/**
+ * Updates the state of the URB when a transfer has been stopped due to an
+ * abnormal condition before the transfer completes. Modifies the
+ * actual_length field of the URB to reflect the number of bytes that have
+ * actually been transferred via the host channel.
+ */
+static void update_urb_state_xfer_intr(struct dwc_hc *hc,
+		 struct dwc_hc_regs *regs, struct urb *urb, struct dwc_qtd *qtd,
+		enum dwc_halt_status sts)
+{
+	u32 xfr_len = get_actual_xfer_length(hc, regs, qtd, sts, NULL);
+	urb->actual_length += xfr_len;
+}
+
+/**
+ * Handles a host channel NAK interrupt. This handler may be called in either
+ * DMA mode or Slave mode.
+ */
+static int handle_hc_nak_intr(struct dwc_hcd *hcd, struct dwc_hc *hc,
+		struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	union hcintmsk_data hcintmsk = {.d32 = 0};
+	/*
+	 * Handle NAK for IN/OUT SSPLIT/CSPLIT transfers, bulk, control, and
+	 * interrupt.  Re-start the SSPLIT transfer.
+	 */
+	if (hc->do_split) {
+		if (hc->complete_split)
+			qtd->error_count = 0;
+
+		qtd->complete_split = 0;
+		halt_channel(hcd, hc, qtd, DWC_OTG_HC_XFER_NAK);
+		goto handle_nak_done;
+	}
+	switch (usb_pipetype(qtd->urb->pipe)) {
+	case PIPE_CONTROL:
+	case PIPE_BULK:
+		if (hcd->core_if->dma_enable && hc->ep_is_in) {
+			/*
+			 * NAK interrupts are enabled on bulk/control IN
+			 * transfers in DMA mode for the sole purpose of
+			 * resetting the error count after a transaction error
+			 * occurs. The core will continue transferring data.
+			 */
+			qtd->error_count = 0;
+			goto handle_nak_done;
+		}
+
+		/*
+		 * NAK interrupts normally occur during OUT transfers in DMA
+		 * or Slave mode. For IN transfers, more requests will be
+		 * queued as request queue space is available.
+		 */
+		qtd->error_count = 0;
+		if (!hc->qh->ping_state) {
+			update_urb_state_xfer_intr(hc, regs, qtd->urb, qtd,
+							DWC_OTG_HC_XFER_NAK);
+
+			save_data_toggle(hc, regs, qtd);
+			if (qtd->urb->dev->speed == USB_SPEED_HIGH)
+				hc->qh->ping_state = 1;
+		}
+
+		/*
+		 * Halt the channel so the transfer can be re-started from
+		 * the appropriate point or the PING protocol will
+		 * start/continue.
+		 */
+		halt_channel(hcd, hc, qtd, DWC_OTG_HC_XFER_NAK);
+		break;
+	case PIPE_INTERRUPT:
+		qtd->error_count = 0;
+		halt_channel(hcd, hc, qtd, DWC_OTG_HC_XFER_NAK);
+		break;
+	case PIPE_ISOCHRONOUS:
+		/* Should never get called for isochronous transfers. */
+		BUG();
+		break;
+	}
+
+handle_nak_done:
+	/* disable nak */
+	hcintmsk.b.nak = 1;
+	dwc_modify_reg32(&regs->hcintmsk, hcintmsk.d32, 0);
+
+	return 1;
+}
+
+/**
+ * Helper function for handle_hc_ack_intr().  Sets the split values for an ACK
+ * on SSPLIT for ISOC OUT.
+ */
+static void set_isoc_out_vals(struct dwc_hc *hc, struct dwc_qtd *qtd)
+{
+	struct usb_iso_packet_descriptor *frame_desc;
+
+	switch (hc->xact_pos) {
+	case DWC_HCSPLIT_XACTPOS_ALL:
+		break;
+	case DWC_HCSPLIT_XACTPOS_END:
+		qtd->isoc_split_pos = DWC_HCSPLIT_XACTPOS_ALL;
+		qtd->isoc_split_offset = 0;
+		break;
+	case DWC_HCSPLIT_XACTPOS_BEGIN:
+	case DWC_HCSPLIT_XACTPOS_MID:
+		/*
+		 * For BEGIN or MID, calculate the length for the next
+		 * microframe to determine the correct SSPLIT token, either MID
+		 * or END.
+		 */
+		frame_desc = &qtd->urb->iso_frame_desc[qtd->isoc_frame_index];
+		qtd->isoc_split_offset += 188;
+
+		if ((frame_desc->length - qtd->isoc_split_offset) <= 188)
+			qtd->isoc_split_pos = DWC_HCSPLIT_XACTPOS_END;
+		else
+			qtd->isoc_split_pos = DWC_HCSPLIT_XACTPOS_MID;
+
+		break;
+	}
+}
+
+/**
+ * Handles a host channel ACK interrupt. This interrupt is enabled when
+ * performing the PING protocol in Slave mode, when errors occur during
+ * either Slave mode or DMA mode, and during Start Split transactions.
+ */
+static int handle_hc_ack_intr(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	union hcintmsk_data hcintmsk = {.d32 = 0};
+
+	if (hc->do_split) {
+		/* Handle ACK on SSPLIT. ACK should not occur in CSPLIT. */
+		if (!hc->ep_is_in && hc->data_pid_start != DWC_OTG_HC_PID_SETUP)
+			qtd->ssplit_out_xfer_count = hc->xfer_len;
+
+		/* Don't need complete for isochronous out transfers. */
+		if (!(hc->ep_type == DWC_OTG_EP_TYPE_ISOC && !hc->ep_is_in))
+			qtd->complete_split = 1;
+
+		if (hc->ep_type == DWC_OTG_EP_TYPE_ISOC && !hc->ep_is_in)
+			set_isoc_out_vals(hc, qtd);
+		else
+			halt_channel(hcd, hc, qtd, DWC_OTG_HC_XFER_ACK);
+	} else {
+		qtd->error_count = 0;
+		if (hc->qh->ping_state) {
+			hc->qh->ping_state = 0;
+
+			/*
+			 * Halt the channel so the transfer can be re-started
+			 * from the appropriate point. This only happens in
+			 * Slave mode. In DMA mode, the ping_state is cleared
+			 * when the transfer is started because the core
+			 * automatically executes the PING, then the transfer.
+			 */
+			halt_channel(hcd, hc, qtd, DWC_OTG_HC_XFER_ACK);
+		}
+	}
+
+	/*
+	 * If the ACK occurred when _not_ in the PING state, let the channel
+	 * continue transferring data after clearing the error count.
+	 */
+	/* disable ack */
+	hcintmsk.b.ack = 1;
+	dwc_modify_reg32(&regs->hcintmsk, hcintmsk.d32, 0);
+
+	return 1;
+}
+
+/**
+ * Handles a host channel NYET interrupt. This interrupt should only occur on
+ * Bulk and Control OUT endpoints and for complete split transactions. If a
+ * NYET occurs at the same time as a Transfer Complete interrupt, it is
+ * handled in the xfercomp interrupt handler, not here. This handler may be
+ * called in either DMA mode or Slave mode.
+ */
+static int handle_hc_nyet_intr(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	union hcintmsk_data hcintmsk = {.d32 = 0};
+
+	/*
+	 * NYET on CSPLIT
+	 * re-do the CSPLIT immediately on non-periodic
+	 */
+	if (hc->do_split && hc->complete_split) {
+		if (hc->ep_type == DWC_OTG_EP_TYPE_INTR ||
+				hc->ep_type == DWC_OTG_EP_TYPE_ISOC) {
+			int frnum = dwc_otg_hcd_get_frame_number(
+					dwc_otg_hcd_to_hcd(hcd));
+			if (dwc_full_frame_num(frnum) !=
+				dwc_full_frame_num(hc->qh->sched_frame)) {
+				qtd->complete_split = 0;
+				halt_channel(hcd, hc, qtd,
+					DWC_OTG_HC_XFER_XACT_ERR);
+
+				goto handle_nyet_done;
+			}
+		}
+
+		halt_channel(hcd, hc, qtd, DWC_OTG_HC_XFER_NYET);
+		goto handle_nyet_done;
+	}
+
+	hc->qh->ping_state = 1;
+	qtd->error_count = 0;
+	update_urb_state_xfer_intr(hc, regs, qtd->urb, qtd,
+				DWC_OTG_HC_XFER_NYET);
+	save_data_toggle(hc, regs, qtd);
+
+	/*
+	 * Halt the channel and re-start the transfer so the PING
+	 * protocol will start.
+	 */
+	halt_channel(hcd, hc, qtd, DWC_OTG_HC_XFER_NYET);
+
+handle_nyet_done:
+	hcintmsk.b.nyet = 1;
+	dwc_modify_reg32(&regs->hcintmsk, hcintmsk.d32, 0);
+
+	/* disable nyet */
+	return 1;
+}
+
+/**
+ * Handles a host channel babble interrupt. This handler may be called in
+ * either DMA mode or Slave mode.
+ */
+static int handle_hc_babble_intr(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	union hcintmsk_data hcintmsk = {.d32 = 0};
+
+	if (hc->ep_type != DWC_OTG_EP_TYPE_ISOC) {
+		dwc_otg_hcd_complete_urb(hcd, qtd->urb, -EOVERFLOW);
+		halt_channel(hcd, hc, qtd, DWC_OTG_HC_XFER_BABBLE_ERR);
+	} else {
+		enum dwc_halt_status halt_status;
+		halt_status = update_isoc_urb_state(hcd, hc, regs, qtd,
+				DWC_OTG_HC_XFER_BABBLE_ERR);
+		halt_channel(hcd, hc, qtd, halt_status);
+	}
+
+	/* disable bblerr */
+	hcintmsk.b.bblerr = 1;
+	dwc_modify_reg32(&regs->hcintmsk, hcintmsk.d32, 0);
+
+	return 1;
+}
+
+/**
+ * Handles a host channel AHB error interrupt. This handler is only called in
+ * DMA mode.
+ */
+static int handle_hc_ahberr_intr(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	union hcchar_data hcchar;
+	union hcsplt_data hcsplt;
+	union hctsiz_data hctsiz;
+	u32 hcdma;
+	struct urb *urb = qtd->urb;
+	union hcintmsk_data hcintmsk = {.d32 = 0};
+
+	hcchar.d32 = dwc_read_reg32(&regs->hcchar);
+	hcsplt.d32 = dwc_read_reg32(&regs->hcsplt);
+	hctsiz.d32 = dwc_read_reg32(&regs->hctsiz);
+	hcdma = dwc_read_reg32(&regs->hcdma);
+
+	printk(KERN_ERR "AHB ERROR, Channel %d\n", hc->hc_num);
+	printk(KERN_ERR "  hcchar 0x%08x, hcsplt 0x%08x\n", hcchar.d32,
+				hcsplt.d32);
+	printk(KERN_ERR "  hctsiz 0x%08x, hcdma 0x%08x\n", hctsiz.d32, hcdma);
+
+	printk(KERN_ERR "  Device address: %d\n", usb_pipedevice(urb->pipe));
+	printk(KERN_ERR "  Endpoint: %d, %s\n", usb_pipeendpoint(urb->pipe),
+			(usb_pipein(urb->pipe) ? "IN" : "OUT"));
+
+	printk(KERN_ERR "  Endpoint type: %s\n", pipetype_str(urb->pipe));
+	printk(KERN_ERR "  Speed: %s\n", dev_speed_str(urb->dev->speed));
+	printk(KERN_ERR "  Max packet size: %d\n",
+		usb_maxpacket(urb->dev, urb->pipe, usb_pipeout(urb->pipe)));
+	printk(KERN_ERR "  Data buffer length: %d\n",
+		urb->transfer_buffer_length);
+	printk(KERN_ERR "  Transfer buffer: %p, Transfer DMA: %p\n",
+		urb->transfer_buffer, (void *) urb->transfer_dma);
+	printk(KERN_ERR "  Setup buffer: %p, Setup DMA: %p\n",
+		urb->setup_packet, (void *) urb->setup_dma);
+	printk(KERN_ERR "  Interval: %d\n", urb->interval);
+
+	dwc_otg_hcd_complete_urb(hcd, urb, -EIO);
+
+	/*
+	 * Force a channel halt. Don't call halt_channel because that won't
+	 * write to the HCCHARn register in DMA mode to force the halt.
+	 */
+	dwc_otg_hc_halt(hcd->core_if, hc, DWC_OTG_HC_XFER_AHB_ERR);
+	/* disable ahberr */
+	hcintmsk.b.ahberr = 1;
+	dwc_modify_reg32(&regs->hcintmsk, hcintmsk.d32, 0);
+
+	return 1;
+}
+
+/**
+ * Handles a host channel transaction error interrupt. This handler may be
+ * called in either DMA mode or Slave mode.
+ */
+static int handle_hc_xacterr_intr(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	enum dwc_halt_status status = DWC_OTG_HC_XFER_XACT_ERR;
+	union hcintmsk_data hcintmsk = {.d32 = 0};
+
+	switch (usb_pipetype(qtd->urb->pipe)) {
+	case PIPE_CONTROL:
+	case PIPE_BULK:
+		qtd->error_count++;
+		if (!hc->qh->ping_state) {
+			update_urb_state_xfer_intr(hc, regs, qtd->urb, qtd,
+							status);
+			save_data_toggle(hc, regs, qtd);
+
+			if (!hc->ep_is_in && qtd->urb->dev->speed ==
+					USB_SPEED_HIGH)
+				hc->qh->ping_state = 1;
+		}
+
+		/*
+		 * Halt the channel so the transfer can be re-started from
+		 * the appropriate point or the PING protocol will start.
+		 */
+		halt_channel(hcd, hc, qtd, status);
+		break;
+	case PIPE_INTERRUPT:
+		qtd->error_count++;
+		if (hc->do_split && hc->complete_split)
+			qtd->complete_split = 0;
+
+		halt_channel(hcd, hc, qtd, status);
+		break;
+	case PIPE_ISOCHRONOUS:
+		status = update_isoc_urb_state(hcd, hc, regs, qtd, status);
+		halt_channel(hcd, hc, qtd, status);
+		break;
+	}
+	/* Disable xacterr */
+	hcintmsk.b.xacterr = 1;
+	dwc_modify_reg32(&regs->hcintmsk, hcintmsk.d32, 0);
+
+	return 1;
+}
+
+/**
+ * Handles a host channel frame overrun interrupt. This handler may be called
+ * in either DMA mode or Slave mode.
+ */
+static int handle_hc_frmovrun_intr(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	enum dwc_halt_status status = DWC_OTG_HC_XFER_FRAME_OVERRUN;
+	union hcintmsk_data hcintmsk = {.d32 = 0};
+
+	switch (usb_pipetype(qtd->urb->pipe)) {
+	case PIPE_CONTROL:
+	case PIPE_BULK:
+		break;
+	case PIPE_INTERRUPT:
+		halt_channel(hcd, hc, qtd, status);
+		break;
+	case PIPE_ISOCHRONOUS:
+		status = update_isoc_urb_state(hcd, hc, regs, qtd, status);
+		halt_channel(hcd, hc, qtd, status);
+		break;
+	}
+	/* Disable frmovrun */
+	hcintmsk.b.frmovrun = 1;
+	dwc_modify_reg32(&regs->hcintmsk, hcintmsk.d32, 0);
+
+	return 1;
+}
+
+/**
+ * Handles a host channel data toggle error interrupt. This handler may be
+ * called in either DMA mode or Slave mode.
+ */
+static int handle_hc_datatglerr_intr(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	union hcintmsk_data hcintmsk = {.d32 = 0};
+
+	if (hc->ep_is_in)
+		qtd->error_count = 0;
+	else
+		printk(KERN_ERR "Data Toggle Error on OUT transfer, channel "
+				"%d\n", hc->hc_num);
+
+	/* disable datatglerr */
+	hcintmsk.b.datatglerr = 1;
+	dwc_modify_reg32(&regs->hcintmsk, hcintmsk.d32, 0);
+
+	return 1;
+}
+
+/**
+ * Handles a host Channel Halted interrupt in DMA mode. This handler
+ * determines the reason the channel halted and proceeds accordingly.
+ */
+static void handle_hc_chhltd_intr_dma(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	union hcint_data hcint;
+	union hcintmsk_data hcintmsk;
+
+	if (hc->halt_status == DWC_OTG_HC_XFER_URB_DEQUEUE ||
+			hc->halt_status == DWC_OTG_HC_XFER_AHB_ERR) {
+		/*
+		 * Just release the channel. A dequeue can happen on a
+		 * transfer timeout. In the case of an AHB Error, the channel
+		 * was forced to halt because there's no way to gracefully
+		 * recover.
+		 */
+		release_channel(hcd, hc, qtd, hc->halt_status);
+		return;
+	}
+
+	/* Read the HCINTn register to determine the cause for the halt. */
+	hcint.d32 = dwc_read_reg32(&regs->hcint);
+	hcintmsk.d32 = dwc_read_reg32(&regs->hcintmsk);
+	if (hcint.b.xfercomp) {
+		/*
+		 * This is here because of a possible hardware bug.  Spec
+		 * says that on SPLIT-ISOC OUT transfers in DMA mode that a HALT
+		 * interrupt w/ACK bit set should occur, but I only see the
+		 * XFERCOMP bit, even with it masked out.  This is a workaround
+		 * for that behavior.  Should fix this when hardware is fixed.
+		 */
+		if (hc->ep_type == DWC_OTG_EP_TYPE_ISOC && !hc->ep_is_in)
+			handle_hc_ack_intr(hcd, hc, regs, qtd);
+
+		handle_hc_xfercomp_intr(hcd, hc, regs, qtd);
+	} else if (hcint.b.stall) {
+		handle_hc_stall_intr(hcd, hc, regs, qtd);
+	} else if (hcint.b.xacterr) {
+		/*
+		 * Must handle xacterr before nak or ack. Could get a xacterr
+		 * at the same time as either of these on a BULK/CONTROL OUT
+		 * that started with a PING. The xacterr takes precedence.
+		 */
+		handle_hc_xacterr_intr(hcd, hc, regs, qtd);
+	} else if (hcint.b.nyet) {
+		/*
+		 * Must handle nyet before nak or ack. Could get a nyet at the
+		 * same time as either of those on a BULK/CONTROL OUT that
+		 * started with a PING. The nyet takes precedence.
+		 */
+		handle_hc_nyet_intr(hcd, hc, regs, qtd);
+	} else if (hcint.b.bblerr) {
+		handle_hc_babble_intr(hcd, hc, regs, qtd);
+	} else if (hcint.b.frmovrun) {
+		handle_hc_frmovrun_intr(hcd, hc, regs, qtd);
+	} else if (hcint.b.nak && !hcintmsk.b.nak) {
+		/*
+		 * If nak is not masked, it's because a non-split IN transfer
+		 * is in an error state. In that case, the nak is handled by
+		 * the nak interrupt handler, not here. Handle nak here for
+		 * BULK/CONTROL OUT transfers, which halt on a NAK to allow
+		 * rewinding the buffer pointer.
+		 */
+		handle_hc_nak_intr(hcd, hc, regs, qtd);
+	} else if (hcint.b.ack && !hcintmsk.b.ack) {
+		/*
+		 * If ack is not masked, it's because a non-split IN transfer
+		 * is in an error state. In that case, the ack is handled by
+		 * the ack interrupt handler, not here. Handle ack here for
+		 * split transfers. Start splits halt on ACK.
+		 */
+		handle_hc_ack_intr(hcd, hc, regs, qtd);
+	} else {
+		if (hc->ep_type == DWC_OTG_EP_TYPE_INTR ||
+				hc->ep_type == DWC_OTG_EP_TYPE_ISOC) {
+			/*
+			 * A periodic transfer halted with no other channel
+			 * interrupts set. Assume it was halted by the core
+			 * because it could not be completed in its scheduled
+			 * (micro)frame.
+			 */
+			halt_channel(hcd, hc, qtd,
+					DWC_OTG_HC_XFER_PERIODIC_INCOMPLETE);
+		} else {
+			printk(KERN_ERR "%s: Channel %d, DMA Mode -- ChHltd "
+				"set, but reason for halting is unknown, "
+				"hcint 0x%08x, intsts 0x%08x\n",
+				__func__, hc->hc_num, hcint.d32,
+				dwc_read_reg32(gintsts_reg(hcd)));
+		}
+	}
+}
+
+/**
+ * Handles a host channel Channel Halted interrupt.
+ *
+ * In slave mode, this handler is called only when the driver specifically
+ * requests a halt. This occurs during handling other host channel interrupts
+ * (e.g. nak, xacterr, stall, nyet, etc.).
+ *
+ * In DMA mode, this is the interrupt that occurs when the core has finished
+ * processing a transfer on a channel. Other host channel interrupts (except
+ * ahberr) are disabled in DMA mode.
+ */
+static int handle_hc_chhltd_intr(struct dwc_hcd *hcd, struct dwc_hc *hc,
+			struct dwc_hc_regs *regs, struct dwc_qtd *qtd)
+{
+	if (hcd->core_if->dma_enable)
+		handle_hc_chhltd_intr_dma(hcd, hc, regs, qtd);
+	else
+		release_channel(hcd, hc, qtd, hc->halt_status);
+
+	return 1;
+}
+
+/* Handles interrupt for a specific Host Channel */
+static int dwc_otg_hcd_handle_hc_n_intr(struct dwc_hcd *hcd, u32 num)
+{
+	int retval = 0;
+	union hcint_data hcint;
+	union hcintmsk_data hcintmsk;
+	struct dwc_hc *hc;
+	struct dwc_hc_regs *hc_regs;
+	struct dwc_qtd *qtd;
+
+	hc = hcd->hc_ptr_array[num];
+	hc_regs = hcd->core_if->host_if->hc_regs[num];
+	qtd = list_entry(hc->qh->qtd_list.next, struct dwc_qtd, qtd_list_entry);
+
+	hcint.d32 = dwc_read_reg32(&hc_regs->hcint);
+	hcintmsk.d32 = dwc_read_reg32(&hc_regs->hcintmsk);
+
+	hcint.d32 = hcint.d32 & hcintmsk.d32;
+	if (!hcd->core_if->dma_enable && hcint.b.chhltd && hcint.d32 != 0x2)
+		hcint.b.chhltd = 0;
+
+	if (hcint.b.xfercomp) {
+		retval |= handle_hc_xfercomp_intr(hcd, hc, hc_regs, qtd);
+		/*
+		 * If NYET occurred at same time as Xfer Complete, the NYET is
+		 * handled by the Xfer Complete interrupt handler. Don't want
+		 * to call the NYET interrupt handler in this case.
+		 */
+		hcint.b.nyet = 0;
+	}
+
+	if (hcint.b.chhltd)
+		retval |= handle_hc_chhltd_intr(hcd, hc, hc_regs, qtd);
+	if (hcint.b.ahberr)
+		retval |= handle_hc_ahberr_intr(hcd, hc, hc_regs, qtd);
+	if (hcint.b.stall)
+		retval |= handle_hc_stall_intr(hcd, hc, hc_regs, qtd);
+	if (hcint.b.nak)
+		retval |= handle_hc_nak_intr(hcd, hc, hc_regs, qtd);
+	if (hcint.b.ack)
+		retval |= handle_hc_ack_intr(hcd, hc, hc_regs, qtd);
+	if (hcint.b.nyet)
+		retval |= handle_hc_nyet_intr(hcd, hc, hc_regs, qtd);
+	if (hcint.b.xacterr)
+		retval |= handle_hc_xacterr_intr(hcd, hc, hc_regs, qtd);
+	if (hcint.b.bblerr)
+		retval |= handle_hc_babble_intr(hcd, hc, hc_regs, qtd);
+	if (hcint.b.frmovrun)
+		retval |= handle_hc_frmovrun_intr(hcd, hc, hc_regs, qtd);
+	if (hcint.b.datatglerr)
+		retval |= handle_hc_datatglerr_intr(hcd, hc, hc_regs, qtd);
+
+	return retval;
+}
+
+/**
+ * This function returns the Host All Channel Interrupt register
+ */
+static inline u32 dwc_otg_read_host_all_channels_intr(struct core_if
+						*core_if)
+{
+	return dwc_read_reg32(&core_if->host_if->host_global_regs->haint);
+}
+
+/**
+ * This interrupt indicates that one or more host channels has a pending
+ * interrupt. There are multiple conditions that can cause each host channel
+ * interrupt. This function determines which conditions have occurred for each
+ * host channel interrupt and handles them appropriately.
+ */
+static int dwc_otg_hcd_handle_hc_intr(struct dwc_hcd *hcd)
+{
+	u32 i;
+	int retval = 0;
+	union haint_data haint;
+
+	/*
+	 * Clear appropriate bits in HCINTn to clear the interrupt bit in
+	 *  GINTSTS
+	 */
+	haint.d32 = dwc_otg_read_host_all_channels_intr(hcd->core_if);
+	for (i = 0; i < hcd->core_if->core_params->host_channels; i++)
+		if (haint.b2.chint & (1 << i))
+			retval |= dwc_otg_hcd_handle_hc_n_intr(hcd, i);
+
+	return retval;
+}
+
+/* This function handles interrupts for the HCD.*/
+int dwc_otg_hcd_handle_intr(struct dwc_hcd *hcd)
+{
+	int ret = 0;
+	struct core_if *core_if = hcd->core_if;
+	union gintsts_data gintsts;
+
+	/* Check if HOST Mode */
+	if (dwc_otg_is_host_mode(core_if)) {
+		spin_lock(&hcd->lock);
+		gintsts.d32 = dwc_otg_read_core_intr(core_if);
+		if (!gintsts.d32) {
+			spin_unlock(&hcd->lock);
+			return IRQ_NONE;
+		}
+
+		if (gintsts.b.sofintr)
+			ret |= dwc_otg_hcd_handle_sof_intr(hcd);
+		if (gintsts.b.rxstsqlvl)
+			ret |= dwc_otg_hcd_handle_rx_status_q_level_intr(hcd);
+		if (gintsts.b.nptxfempty)
+			ret |= dwc_otg_hcd_handle_np_tx_fifo_empty_intr(hcd);
+		if (gintsts.b.portintr)
+			ret |= dwc_otg_hcd_handle_port_intr(hcd);
+		if (gintsts.b.hcintr)
+			ret |= dwc_otg_hcd_handle_hc_intr(hcd);
+		if (gintsts.b.ptxfempty)
+			ret |= dwc_otg_hcd_handle_perio_tx_fifo_empty_intr(hcd);
+
+		spin_unlock(&hcd->lock);
+	}
+	return ret;
+}
-- 
1.6.0.1