Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 2109 insertions, 0 deletions

diff --git a/kernel/drivers/usb/dwc2/hcd_intr.c b/kernel/drivers/usb/dwc2/hcd_intr.c
new file mode 100644
index 000000000..551ba878b
--- /dev/null
+++ b/kernel/drivers/usb/dwc2/hcd_intr.c
@@ -0,0 +1,2109 @@
+/*
+ * hcd_intr.c - DesignWare HS OTG Controller host-mode interrupt handling
+ *
+ * Copyright (C) 2004-2013 Synopsys, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The names of the above-listed copyright holders may not be used
+ *    to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") as published by the Free Software
+ * Foundation; either version 2 of the License, or (at your option) any
+ * later version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR
+ * CONTRIBUTORS 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 file contains the interrupt handlers for Host mode
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/dma-mapping.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#include <linux/usb/hcd.h>
+#include <linux/usb/ch11.h>
+
+#include "core.h"
+#include "hcd.h"
+
+/* This function is for debug only */
+static void dwc2_track_missed_sofs(struct dwc2_hsotg *hsotg)
+{
+#ifdef CONFIG_USB_DWC2_TRACK_MISSED_SOFS
+	u16 curr_frame_number = hsotg->frame_number;
+
+	if (hsotg->frame_num_idx < FRAME_NUM_ARRAY_SIZE) {
+		if (((hsotg->last_frame_num + 1) & HFNUM_MAX_FRNUM) !=
+		    curr_frame_number) {
+			hsotg->frame_num_array[hsotg->frame_num_idx] =
+					curr_frame_number;
+			hsotg->last_frame_num_array[hsotg->frame_num_idx] =
+					hsotg->last_frame_num;
+			hsotg->frame_num_idx++;
+		}
+	} else if (!hsotg->dumped_frame_num_array) {
+		int i;
+
+		dev_info(hsotg->dev, "Frame     Last Frame\n");
+		dev_info(hsotg->dev, "-----     ----------\n");
+		for (i = 0; i < FRAME_NUM_ARRAY_SIZE; i++) {
+			dev_info(hsotg->dev, "0x%04x    0x%04x\n",
+				 hsotg->frame_num_array[i],
+				 hsotg->last_frame_num_array[i]);
+		}
+		hsotg->dumped_frame_num_array = 1;
+	}
+	hsotg->last_frame_num = curr_frame_number;
+#endif
+}
+
+static void dwc2_hc_handle_tt_clear(struct dwc2_hsotg *hsotg,
+				    struct dwc2_host_chan *chan,
+				    struct dwc2_qtd *qtd)
+{
+	struct urb *usb_urb;
+
+	if (!chan->qh)
+		return;
+
+	if (chan->qh->dev_speed == USB_SPEED_HIGH)
+		return;
+
+	if (!qtd->urb)
+		return;
+
+	usb_urb = qtd->urb->priv;
+	if (!usb_urb || !usb_urb->dev || !usb_urb->dev->tt)
+		return;
+
+	if (qtd->urb->status != -EPIPE && qtd->urb->status != -EREMOTEIO) {
+		chan->qh->tt_buffer_dirty = 1;
+		if (usb_hub_clear_tt_buffer(usb_urb))
+			/* Clear failed; let's hope things work anyway */
+			chan->qh->tt_buffer_dirty = 0;
+	}
+}
+
+/*
+ * 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 void dwc2_sof_intr(struct dwc2_hsotg *hsotg)
+{
+	struct list_head *qh_entry;
+	struct dwc2_qh *qh;
+	enum dwc2_transaction_type tr_type;
+
+#ifdef DEBUG_SOF
+	dev_vdbg(hsotg->dev, "--Start of Frame Interrupt--\n");
+#endif
+
+	hsotg->frame_number = dwc2_hcd_get_frame_number(hsotg);
+
+	dwc2_track_missed_sofs(hsotg);
+
+	/* Determine whether any periodic QHs should be executed */
+	qh_entry = hsotg->periodic_sched_inactive.next;
+	while (qh_entry != &hsotg->periodic_sched_inactive) {
+		qh = list_entry(qh_entry, struct dwc2_qh, qh_list_entry);
+		qh_entry = qh_entry->next;
+		if (dwc2_frame_num_le(qh->sched_frame, hsotg->frame_number))
+			/*
+			 * Move QH to the ready list to be executed next
+			 * (micro)frame
+			 */
+			list_move(&qh->qh_list_entry,
+				  &hsotg->periodic_sched_ready);
+	}
+	tr_type = dwc2_hcd_select_transactions(hsotg);
+	if (tr_type != DWC2_TRANSACTION_NONE)
+		dwc2_hcd_queue_transactions(hsotg, tr_type);
+
+	/* Clear interrupt */
+	writel(GINTSTS_SOF, hsotg->regs + GINTSTS);
+}
+
+/*
+ * Handles the Rx FIFO 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 void dwc2_rx_fifo_level_intr(struct dwc2_hsotg *hsotg)
+{
+	u32 grxsts, chnum, bcnt, dpid, pktsts;
+	struct dwc2_host_chan *chan;
+
+	if (dbg_perio())
+		dev_vdbg(hsotg->dev, "--RxFIFO Level Interrupt--\n");
+
+	grxsts = readl(hsotg->regs + GRXSTSP);
+	chnum = (grxsts & GRXSTS_HCHNUM_MASK) >> GRXSTS_HCHNUM_SHIFT;
+	chan = hsotg->hc_ptr_array[chnum];
+	if (!chan) {
+		dev_err(hsotg->dev, "Unable to get corresponding channel\n");
+		return;
+	}
+
+	bcnt = (grxsts & GRXSTS_BYTECNT_MASK) >> GRXSTS_BYTECNT_SHIFT;
+	dpid = (grxsts & GRXSTS_DPID_MASK) >> GRXSTS_DPID_SHIFT;
+	pktsts = (grxsts & GRXSTS_PKTSTS_MASK) >> GRXSTS_PKTSTS_SHIFT;
+
+	/* Packet Status */
+	if (dbg_perio()) {
+		dev_vdbg(hsotg->dev, "    Ch num = %d\n", chnum);
+		dev_vdbg(hsotg->dev, "    Count = %d\n", bcnt);
+		dev_vdbg(hsotg->dev, "    DPID = %d, chan.dpid = %d\n", dpid,
+			 chan->data_pid_start);
+		dev_vdbg(hsotg->dev, "    PStatus = %d\n", pktsts);
+	}
+
+	switch (pktsts) {
+	case GRXSTS_PKTSTS_HCHIN:
+		/* Read the data into the host buffer */
+		if (bcnt > 0) {
+			dwc2_read_packet(hsotg, chan->xfer_buf, bcnt);
+
+			/* Update the HC fields for the next packet received */
+			chan->xfer_count += bcnt;
+			chan->xfer_buf += bcnt;
+		}
+		break;
+	case GRXSTS_PKTSTS_HCHIN_XFER_COMP:
+	case GRXSTS_PKTSTS_DATATOGGLEERR:
+	case GRXSTS_PKTSTS_HCHHALTED:
+		/* Handled in interrupt, just ignore data */
+		break;
+	default:
+		dev_err(hsotg->dev,
+			"RxFIFO Level Interrupt: Unknown status %d\n", pktsts);
+		break;
+	}
+}
+
+/*
+ * 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 void dwc2_np_tx_fifo_empty_intr(struct dwc2_hsotg *hsotg)
+{
+	dev_vdbg(hsotg->dev, "--Non-Periodic TxFIFO Empty Interrupt--\n");
+	dwc2_hcd_queue_transactions(hsotg, DWC2_TRANSACTION_NON_PERIODIC);
+}
+
+/*
+ * 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 void dwc2_perio_tx_fifo_empty_intr(struct dwc2_hsotg *hsotg)
+{
+	if (dbg_perio())
+		dev_vdbg(hsotg->dev, "--Periodic TxFIFO Empty Interrupt--\n");
+	dwc2_hcd_queue_transactions(hsotg, DWC2_TRANSACTION_PERIODIC);
+}
+
+static void dwc2_hprt0_enable(struct dwc2_hsotg *hsotg, u32 hprt0,
+			      u32 *hprt0_modify)
+{
+	struct dwc2_core_params *params = hsotg->core_params;
+	int do_reset = 0;
+	u32 usbcfg;
+	u32 prtspd;
+	u32 hcfg;
+	u32 fslspclksel;
+	u32 hfir;
+
+	dev_vdbg(hsotg->dev, "%s(%p)\n", __func__, hsotg);
+
+	/* Every time when port enables calculate HFIR.FrInterval */
+	hfir = readl(hsotg->regs + HFIR);
+	hfir &= ~HFIR_FRINT_MASK;
+	hfir |= dwc2_calc_frame_interval(hsotg) << HFIR_FRINT_SHIFT &
+		HFIR_FRINT_MASK;
+	writel(hfir, hsotg->regs + HFIR);
+
+	/* Check if we need to adjust the PHY clock speed for low power */
+	if (!params->host_support_fs_ls_low_power) {
+		/* Port has been enabled, set the reset change flag */
+		hsotg->flags.b.port_reset_change = 1;
+		return;
+	}
+
+	usbcfg = readl(hsotg->regs + GUSBCFG);
+	prtspd = (hprt0 & HPRT0_SPD_MASK) >> HPRT0_SPD_SHIFT;
+
+	if (prtspd == HPRT0_SPD_LOW_SPEED || prtspd == HPRT0_SPD_FULL_SPEED) {
+		/* Low power */
+		if (!(usbcfg & GUSBCFG_PHY_LP_CLK_SEL)) {
+			/* Set PHY low power clock select for FS/LS devices */
+			usbcfg |= GUSBCFG_PHY_LP_CLK_SEL;
+			writel(usbcfg, hsotg->regs + GUSBCFG);
+			do_reset = 1;
+		}
+
+		hcfg = readl(hsotg->regs + HCFG);
+		fslspclksel = (hcfg & HCFG_FSLSPCLKSEL_MASK) >>
+			      HCFG_FSLSPCLKSEL_SHIFT;
+
+		if (prtspd == HPRT0_SPD_LOW_SPEED &&
+		    params->host_ls_low_power_phy_clk ==
+		    DWC2_HOST_LS_LOW_POWER_PHY_CLK_PARAM_6MHZ) {
+			/* 6 MHZ */
+			dev_vdbg(hsotg->dev,
+				 "FS_PHY programming HCFG to 6 MHz\n");
+			if (fslspclksel != HCFG_FSLSPCLKSEL_6_MHZ) {
+				fslspclksel = HCFG_FSLSPCLKSEL_6_MHZ;
+				hcfg &= ~HCFG_FSLSPCLKSEL_MASK;
+				hcfg |= fslspclksel << HCFG_FSLSPCLKSEL_SHIFT;
+				writel(hcfg, hsotg->regs + HCFG);
+				do_reset = 1;
+			}
+		} else {
+			/* 48 MHZ */
+			dev_vdbg(hsotg->dev,
+				 "FS_PHY programming HCFG to 48 MHz\n");
+			if (fslspclksel != HCFG_FSLSPCLKSEL_48_MHZ) {
+				fslspclksel = HCFG_FSLSPCLKSEL_48_MHZ;
+				hcfg &= ~HCFG_FSLSPCLKSEL_MASK;
+				hcfg |= fslspclksel << HCFG_FSLSPCLKSEL_SHIFT;
+				writel(hcfg, hsotg->regs + HCFG);
+				do_reset = 1;
+			}
+		}
+	} else {
+		/* Not low power */
+		if (usbcfg & GUSBCFG_PHY_LP_CLK_SEL) {
+			usbcfg &= ~GUSBCFG_PHY_LP_CLK_SEL;
+			writel(usbcfg, hsotg->regs + GUSBCFG);
+			do_reset = 1;
+		}
+	}
+
+	if (do_reset) {
+		*hprt0_modify |= HPRT0_RST;
+		queue_delayed_work(hsotg->wq_otg, &hsotg->reset_work,
+				   msecs_to_jiffies(60));
+	} else {
+		/* Port has been enabled, set the reset change flag */
+		hsotg->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 void dwc2_port_intr(struct dwc2_hsotg *hsotg)
+{
+	u32 hprt0;
+	u32 hprt0_modify;
+
+	dev_vdbg(hsotg->dev, "--Port Interrupt--\n");
+
+	hprt0 = readl(hsotg->regs + HPRT0);
+	hprt0_modify = hprt0;
+
+	/*
+	 * Clear appropriate bits in HPRT0 to clear the interrupt bit in
+	 * GINTSTS
+	 */
+	hprt0_modify &= ~(HPRT0_ENA | HPRT0_CONNDET | HPRT0_ENACHG |
+			  HPRT0_OVRCURRCHG);
+
+	/*
+	 * Port Connect Detected
+	 * Set flag and clear if detected
+	 */
+	if (hprt0 & HPRT0_CONNDET) {
+		dev_vdbg(hsotg->dev,
+			 "--Port Interrupt HPRT0=0x%08x Port Connect Detected--\n",
+			 hprt0);
+		hsotg->flags.b.port_connect_status_change = 1;
+		hsotg->flags.b.port_connect_status = 1;
+		hprt0_modify |= HPRT0_CONNDET;
+
+		/*
+		 * The Hub driver asserts a reset when it sees port connect
+		 * status change flag
+		 */
+	}
+
+	/*
+	 * Port Enable Changed
+	 * Clear if detected - Set internal flag if disabled
+	 */
+	if (hprt0 & HPRT0_ENACHG) {
+		dev_vdbg(hsotg->dev,
+			 "  --Port Interrupt HPRT0=0x%08x Port Enable Changed (now %d)--\n",
+			 hprt0, !!(hprt0 & HPRT0_ENA));
+		hprt0_modify |= HPRT0_ENACHG;
+		if (hprt0 & HPRT0_ENA)
+			dwc2_hprt0_enable(hsotg, hprt0, &hprt0_modify);
+		else
+			hsotg->flags.b.port_enable_change = 1;
+	}
+
+	/* Overcurrent Change Interrupt */
+	if (hprt0 & HPRT0_OVRCURRCHG) {
+		dev_vdbg(hsotg->dev,
+			 "  --Port Interrupt HPRT0=0x%08x Port Overcurrent Changed--\n",
+			 hprt0);
+		hsotg->flags.b.port_over_current_change = 1;
+		hprt0_modify |= HPRT0_OVRCURRCHG;
+	}
+
+	/* Clear Port Interrupts */
+	writel(hprt0_modify, hsotg->regs + HPRT0);
+}
+
+/*
+ * 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 DWC2_HC_XFER_COMPLETE, *short_read
+ * is set to 1 upon return if less than the requested number of bytes were
+ * transferred. short_read may also be NULL on entry, in which case it remains
+ * unchanged.
+ */
+static u32 dwc2_get_actual_xfer_length(struct dwc2_hsotg *hsotg,
+				       struct dwc2_host_chan *chan, int chnum,
+				       struct dwc2_qtd *qtd,
+				       enum dwc2_halt_status halt_status,
+				       int *short_read)
+{
+	u32 hctsiz, count, length;
+
+	hctsiz = readl(hsotg->regs + HCTSIZ(chnum));
+
+	if (halt_status == DWC2_HC_XFER_COMPLETE) {
+		if (chan->ep_is_in) {
+			count = (hctsiz & TSIZ_XFERSIZE_MASK) >>
+				TSIZ_XFERSIZE_SHIFT;
+			length = chan->xfer_len - count;
+			if (short_read != NULL)
+				*short_read = (count != 0);
+		} else if (chan->qh->do_split) {
+			length = qtd->ssplit_out_xfer_count;
+		} else {
+			length = chan->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).
+		 */
+		count = (hctsiz & TSIZ_PKTCNT_MASK) >> TSIZ_PKTCNT_SHIFT;
+		length = (chan->start_pkt_count - count) * chan->max_packet;
+	}
+
+	return length;
+}
+
+/**
+ * dwc2_update_urb_state() - 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.
+ *
+ * Return: 1 if the data transfer specified by the URB is completely finished,
+ * 0 otherwise
+ */
+static int dwc2_update_urb_state(struct dwc2_hsotg *hsotg,
+				 struct dwc2_host_chan *chan, int chnum,
+				 struct dwc2_hcd_urb *urb,
+				 struct dwc2_qtd *qtd)
+{
+	u32 hctsiz;
+	int xfer_done = 0;
+	int short_read = 0;
+	int xfer_length = dwc2_get_actual_xfer_length(hsotg, chan, chnum, qtd,
+						      DWC2_HC_XFER_COMPLETE,
+						      &short_read);
+
+	if (urb->actual_length + xfer_length > urb->length) {
+		dev_warn(hsotg->dev, "%s(): trimming xfer length\n", __func__);
+		xfer_length = urb->length - urb->actual_length;
+	}
+
+	/* Non DWORD-aligned buffer case handling */
+	if (chan->align_buf && xfer_length && chan->ep_is_in) {
+		dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n", __func__);
+		memcpy(urb->buf + urb->actual_length, chan->qh->dw_align_buf,
+		       xfer_length);
+	}
+
+	dev_vdbg(hsotg->dev, "urb->actual_length=%d xfer_length=%d\n",
+		 urb->actual_length, xfer_length);
+	urb->actual_length += xfer_length;
+
+	if (xfer_length && chan->ep_type == USB_ENDPOINT_XFER_BULK &&
+	    (urb->flags & URB_SEND_ZERO_PACKET) &&
+	    urb->actual_length >= urb->length &&
+	    !(urb->length % chan->max_packet)) {
+		xfer_done = 0;
+	} else if (short_read || urb->actual_length >= urb->length) {
+		xfer_done = 1;
+		urb->status = 0;
+	}
+
+	hctsiz = readl(hsotg->regs + HCTSIZ(chnum));
+	dev_vdbg(hsotg->dev, "DWC_otg: %s: %s, channel %d\n",
+		 __func__, (chan->ep_is_in ? "IN" : "OUT"), chnum);
+	dev_vdbg(hsotg->dev, "  chan->xfer_len %d\n", chan->xfer_len);
+	dev_vdbg(hsotg->dev, "  hctsiz.xfersize %d\n",
+		 (hctsiz & TSIZ_XFERSIZE_MASK) >> TSIZ_XFERSIZE_SHIFT);
+	dev_vdbg(hsotg->dev, "  urb->transfer_buffer_length %d\n", urb->length);
+	dev_vdbg(hsotg->dev, "  urb->actual_length %d\n", urb->actual_length);
+	dev_vdbg(hsotg->dev, "  short_read %d, xfer_done %d\n", short_read,
+		 xfer_done);
+
+	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.
+ */
+void dwc2_hcd_save_data_toggle(struct dwc2_hsotg *hsotg,
+			       struct dwc2_host_chan *chan, int chnum,
+			       struct dwc2_qtd *qtd)
+{
+	u32 hctsiz = readl(hsotg->regs + HCTSIZ(chnum));
+	u32 pid = (hctsiz & TSIZ_SC_MC_PID_MASK) >> TSIZ_SC_MC_PID_SHIFT;
+
+	if (chan->ep_type != USB_ENDPOINT_XFER_CONTROL) {
+		if (pid == TSIZ_SC_MC_PID_DATA0)
+			chan->qh->data_toggle = DWC2_HC_PID_DATA0;
+		else
+			chan->qh->data_toggle = DWC2_HC_PID_DATA1;
+	} else {
+		if (pid == TSIZ_SC_MC_PID_DATA0)
+			qtd->data_toggle = DWC2_HC_PID_DATA0;
+		else
+			qtd->data_toggle = DWC2_HC_PID_DATA1;
+	}
+}
+
+/**
+ * dwc2_update_isoc_urb_state() - 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
+ * halt_status. Completes the Isochronous URB if all the URB frames have been
+ * completed.
+ *
+ * Return: DWC2_HC_XFER_COMPLETE if there are more frames remaining to be
+ * transferred in the URB. Otherwise return DWC2_HC_XFER_URB_COMPLETE.
+ */
+static enum dwc2_halt_status dwc2_update_isoc_urb_state(
+		struct dwc2_hsotg *hsotg, struct dwc2_host_chan *chan,
+		int chnum, struct dwc2_qtd *qtd,
+		enum dwc2_halt_status halt_status)
+{
+	struct dwc2_hcd_iso_packet_desc *frame_desc;
+	struct dwc2_hcd_urb *urb = qtd->urb;
+
+	if (!urb)
+		return DWC2_HC_XFER_NO_HALT_STATUS;
+
+	frame_desc = &urb->iso_descs[qtd->isoc_frame_index];
+
+	switch (halt_status) {
+	case DWC2_HC_XFER_COMPLETE:
+		frame_desc->status = 0;
+		frame_desc->actual_length = dwc2_get_actual_xfer_length(hsotg,
+					chan, chnum, qtd, halt_status, NULL);
+
+		/* Non DWORD-aligned buffer case handling */
+		if (chan->align_buf && frame_desc->actual_length &&
+		    chan->ep_is_in) {
+			dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n",
+				 __func__);
+			memcpy(urb->buf + frame_desc->offset +
+			       qtd->isoc_split_offset, chan->qh->dw_align_buf,
+			       frame_desc->actual_length);
+		}
+		break;
+	case DWC2_HC_XFER_FRAME_OVERRUN:
+		urb->error_count++;
+		if (chan->ep_is_in)
+			frame_desc->status = -ENOSR;
+		else
+			frame_desc->status = -ECOMM;
+		frame_desc->actual_length = 0;
+		break;
+	case DWC2_HC_XFER_BABBLE_ERR:
+		urb->error_count++;
+		frame_desc->status = -EOVERFLOW;
+		/* Don't need to update actual_length in this case */
+		break;
+	case DWC2_HC_XFER_XACT_ERR:
+		urb->error_count++;
+		frame_desc->status = -EPROTO;
+		frame_desc->actual_length = dwc2_get_actual_xfer_length(hsotg,
+					chan, chnum, qtd, halt_status, NULL);
+
+		/* Non DWORD-aligned buffer case handling */
+		if (chan->align_buf && frame_desc->actual_length &&
+		    chan->ep_is_in) {
+			dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n",
+				 __func__);
+			memcpy(urb->buf + frame_desc->offset +
+			       qtd->isoc_split_offset, chan->qh->dw_align_buf,
+			       frame_desc->actual_length);
+		}
+
+		/* Skip whole frame */
+		if (chan->qh->do_split &&
+		    chan->ep_type == USB_ENDPOINT_XFER_ISOC && chan->ep_is_in &&
+		    hsotg->core_params->dma_enable > 0) {
+			qtd->complete_split = 0;
+			qtd->isoc_split_offset = 0;
+		}
+
+		break;
+	default:
+		dev_err(hsotg->dev, "Unhandled halt_status (%d)\n",
+			halt_status);
+		break;
+	}
+
+	if (++qtd->isoc_frame_index == urb->packet_count) {
+		/*
+		 * urb->status is not used for isoc transfers. The individual
+		 * frame_desc statuses are used instead.
+		 */
+		dwc2_host_complete(hsotg, qtd, 0);
+		halt_status = DWC2_HC_XFER_URB_COMPLETE;
+	} else {
+		halt_status = DWC2_HC_XFER_COMPLETE;
+	}
+
+	return halt_status;
+}
+
+/*
+ * 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 dwc2_deactivate_qh(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
+			       int free_qtd)
+{
+	int continue_split = 0;
+	struct dwc2_qtd *qtd;
+
+	if (dbg_qh(qh))
+		dev_vdbg(hsotg->dev, "  %s(%p,%p,%d)\n", __func__,
+			 hsotg, qh, free_qtd);
+
+	if (list_empty(&qh->qtd_list)) {
+		dev_dbg(hsotg->dev, "## QTD list empty ##\n");
+		goto no_qtd;
+	}
+
+	qtd = list_first_entry(&qh->qtd_list, struct dwc2_qtd, qtd_list_entry);
+
+	if (qtd->complete_split)
+		continue_split = 1;
+	else if (qtd->isoc_split_pos == DWC2_HCSPLT_XACTPOS_MID ||
+		 qtd->isoc_split_pos == DWC2_HCSPLT_XACTPOS_END)
+		continue_split = 1;
+
+	if (free_qtd) {
+		dwc2_hcd_qtd_unlink_and_free(hsotg, qtd, qh);
+		continue_split = 0;
+	}
+
+no_qtd:
+	if (qh->channel)
+		qh->channel->align_buf = 0;
+	qh->channel = NULL;
+	dwc2_hcd_qh_deactivate(hsotg, qh, continue_split);
+}
+
+/**
+ * dwc2_release_channel() - Releases a host channel for use by other transfers
+ *
+ * @hsotg:       The HCD state structure
+ * @chan:        The host channel to release
+ * @qtd:         The QTD associated with the host channel. This QTD may be
+ *               freed if the transfer is complete or an error has occurred.
+ * @halt_status: Reason the channel is being released. This status
+ *               determines the actions taken by this function.
+ *
+ * Also attempts to select and queue more transactions since at least one host
+ * channel is available.
+ */
+static void dwc2_release_channel(struct dwc2_hsotg *hsotg,
+				 struct dwc2_host_chan *chan,
+				 struct dwc2_qtd *qtd,
+				 enum dwc2_halt_status halt_status)
+{
+	enum dwc2_transaction_type tr_type;
+	u32 haintmsk;
+	int free_qtd = 0;
+
+	if (dbg_hc(chan))
+		dev_vdbg(hsotg->dev, "  %s: channel %d, halt_status %d\n",
+			 __func__, chan->hc_num, halt_status);
+
+	switch (halt_status) {
+	case DWC2_HC_XFER_URB_COMPLETE:
+		free_qtd = 1;
+		break;
+	case DWC2_HC_XFER_AHB_ERR:
+	case DWC2_HC_XFER_STALL:
+	case DWC2_HC_XFER_BABBLE_ERR:
+		free_qtd = 1;
+		break;
+	case DWC2_HC_XFER_XACT_ERR:
+		if (qtd && qtd->error_count >= 3) {
+			dev_vdbg(hsotg->dev,
+				 "  Complete URB with transaction error\n");
+			free_qtd = 1;
+			dwc2_host_complete(hsotg, qtd, -EPROTO);
+		}
+		break;
+	case DWC2_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 DWC2_HC_XFER_PERIODIC_INCOMPLETE:
+		dev_vdbg(hsotg->dev, "  Complete URB with I/O error\n");
+		free_qtd = 1;
+		dwc2_host_complete(hsotg, qtd, -EIO);
+		break;
+	case DWC2_HC_XFER_NO_HALT_STATUS:
+	default:
+		break;
+	}
+
+	dwc2_deactivate_qh(hsotg, chan->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.
+	 */
+	if (!list_empty(&chan->hc_list_entry))
+		list_del(&chan->hc_list_entry);
+	dwc2_hc_cleanup(hsotg, chan);
+	list_add_tail(&chan->hc_list_entry, &hsotg->free_hc_list);
+
+	if (hsotg->core_params->uframe_sched > 0) {
+		hsotg->available_host_channels++;
+	} else {
+		switch (chan->ep_type) {
+		case USB_ENDPOINT_XFER_CONTROL:
+		case USB_ENDPOINT_XFER_BULK:
+			hsotg->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;
+		}
+	}
+
+	haintmsk = readl(hsotg->regs + HAINTMSK);
+	haintmsk &= ~(1 << chan->hc_num);
+	writel(haintmsk, hsotg->regs + HAINTMSK);
+
+	/* Try to queue more transfers now that there's a free channel */
+	tr_type = dwc2_hcd_select_transactions(hsotg);
+	if (tr_type != DWC2_TRANSACTION_NONE)
+		dwc2_hcd_queue_transactions(hsotg, 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 dwc2_halt_channel(struct dwc2_hsotg *hsotg,
+			      struct dwc2_host_chan *chan, struct dwc2_qtd *qtd,
+			      enum dwc2_halt_status halt_status)
+{
+	if (dbg_hc(chan))
+		dev_vdbg(hsotg->dev, "%s()\n", __func__);
+
+	if (hsotg->core_params->dma_enable > 0) {
+		if (dbg_hc(chan))
+			dev_vdbg(hsotg->dev, "DMA enabled\n");
+		dwc2_release_channel(hsotg, chan, qtd, halt_status);
+		return;
+	}
+
+	/* Slave mode processing */
+	dwc2_hc_halt(hsotg, chan, halt_status);
+
+	if (chan->halt_on_queue) {
+		u32 gintmsk;
+
+		dev_vdbg(hsotg->dev, "Halt on queue\n");
+		if (chan->ep_type == USB_ENDPOINT_XFER_CONTROL ||
+		    chan->ep_type == USB_ENDPOINT_XFER_BULK) {
+			dev_vdbg(hsotg->dev, "control/bulk\n");
+			/*
+			 * Make sure the Non-periodic Tx FIFO empty interrupt
+			 * is enabled so that the non-periodic schedule will
+			 * be processed
+			 */
+			gintmsk = readl(hsotg->regs + GINTMSK);
+			gintmsk |= GINTSTS_NPTXFEMP;
+			writel(gintmsk, hsotg->regs + GINTMSK);
+		} else {
+			dev_vdbg(hsotg->dev, "isoc/intr\n");
+			/*
+			 * 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(&chan->qh->qh_list_entry,
+				  &hsotg->periodic_sched_assigned);
+
+			/*
+			 * Make sure the Periodic Tx FIFO Empty interrupt is
+			 * enabled so that the periodic schedule will be
+			 * processed
+			 */
+			gintmsk = readl(hsotg->regs + GINTMSK);
+			gintmsk |= GINTSTS_PTXFEMP;
+			writel(gintmsk, hsotg->regs + GINTMSK);
+		}
+	}
+}
+
+/*
+ * 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 dwc2_complete_non_periodic_xfer(struct dwc2_hsotg *hsotg,
+					    struct dwc2_host_chan *chan,
+					    int chnum, struct dwc2_qtd *qtd,
+					    enum dwc2_halt_status halt_status)
+{
+	dev_vdbg(hsotg->dev, "%s()\n", __func__);
+
+	qtd->error_count = 0;
+
+	if (chan->hcint & HCINTMSK_NYET) {
+		/*
+		 * 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.
+		 */
+		dev_vdbg(hsotg->dev, "got NYET\n");
+		chan->qh->ping_state = 1;
+	}
+
+	/*
+	 * 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 dwc2_hcd_queue_transactions, which also enables the
+	 * Tx FIFO Empty interrupt if necessary.
+	 */
+	if (chan->ep_is_in) {
+		/*
+		 * IN transfers in Slave mode require an explicit disable to
+		 * halt the channel. (In DMA mode, this call simply releases
+		 * the channel.)
+		 */
+		dwc2_halt_channel(hsotg, chan, qtd, halt_status);
+	} else {
+		/*
+		 * The channel is automatically disabled by the core for OUT
+		 * transfers in Slave mode
+		 */
+		dwc2_release_channel(hsotg, chan, 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 dwc2_complete_periodic_xfer(struct dwc2_hsotg *hsotg,
+					struct dwc2_host_chan *chan, int chnum,
+					struct dwc2_qtd *qtd,
+					enum dwc2_halt_status halt_status)
+{
+	u32 hctsiz = readl(hsotg->regs + HCTSIZ(chnum));
+
+	qtd->error_count = 0;
+
+	if (!chan->ep_is_in || (hctsiz & TSIZ_PKTCNT_MASK) == 0)
+		/* Core halts channel in these cases */
+		dwc2_release_channel(hsotg, chan, qtd, halt_status);
+	else
+		/* Flush any outstanding requests from the Tx queue */
+		dwc2_halt_channel(hsotg, chan, qtd, halt_status);
+}
+
+static int dwc2_xfercomp_isoc_split_in(struct dwc2_hsotg *hsotg,
+				       struct dwc2_host_chan *chan, int chnum,
+				       struct dwc2_qtd *qtd)
+{
+	struct dwc2_hcd_iso_packet_desc *frame_desc;
+	u32 len;
+
+	if (!qtd->urb)
+		return 0;
+
+	frame_desc = &qtd->urb->iso_descs[qtd->isoc_frame_index];
+	len = dwc2_get_actual_xfer_length(hsotg, chan, chnum, qtd,
+					  DWC2_HC_XFER_COMPLETE, NULL);
+	if (!len) {
+		qtd->complete_split = 0;
+		qtd->isoc_split_offset = 0;
+		return 0;
+	}
+
+	frame_desc->actual_length += len;
+
+	if (chan->align_buf) {
+		dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n", __func__);
+		memcpy(qtd->urb->buf + frame_desc->offset +
+		       qtd->isoc_split_offset, chan->qh->dw_align_buf, len);
+	}
+
+	qtd->isoc_split_offset += len;
+
+	if (frame_desc->actual_length >= frame_desc->length) {
+		frame_desc->status = 0;
+		qtd->isoc_frame_index++;
+		qtd->complete_split = 0;
+		qtd->isoc_split_offset = 0;
+	}
+
+	if (qtd->isoc_frame_index == qtd->urb->packet_count) {
+		dwc2_host_complete(hsotg, qtd, 0);
+		dwc2_release_channel(hsotg, chan, qtd,
+				     DWC2_HC_XFER_URB_COMPLETE);
+	} else {
+		dwc2_release_channel(hsotg, chan, qtd,
+				     DWC2_HC_XFER_NO_HALT_STATUS);
+	}
+
+	return 1;	/* Indicates that channel released */
+}
+
+/*
+ * Handles a host channel Transfer Complete interrupt. This handler may be
+ * called in either DMA mode or Slave mode.
+ */
+static void dwc2_hc_xfercomp_intr(struct dwc2_hsotg *hsotg,
+				  struct dwc2_host_chan *chan, int chnum,
+				  struct dwc2_qtd *qtd)
+{
+	struct dwc2_hcd_urb *urb = qtd->urb;
+	enum dwc2_halt_status halt_status = DWC2_HC_XFER_COMPLETE;
+	int pipe_type;
+	int urb_xfer_done;
+
+	if (dbg_hc(chan))
+		dev_vdbg(hsotg->dev,
+			 "--Host Channel %d Interrupt: Transfer Complete--\n",
+			 chnum);
+
+	if (!urb)
+		goto handle_xfercomp_done;
+
+	pipe_type = dwc2_hcd_get_pipe_type(&urb->pipe_info);
+
+	if (hsotg->core_params->dma_desc_enable > 0) {
+		dwc2_hcd_complete_xfer_ddma(hsotg, chan, chnum, halt_status);
+		if (pipe_type == USB_ENDPOINT_XFER_ISOC)
+			/* Do not disable the interrupt, just clear it */
+			return;
+		goto handle_xfercomp_done;
+	}
+
+	/* Handle xfer complete on CSPLIT */
+	if (chan->qh->do_split) {
+		if (chan->ep_type == USB_ENDPOINT_XFER_ISOC && chan->ep_is_in &&
+		    hsotg->core_params->dma_enable > 0) {
+			if (qtd->complete_split &&
+			    dwc2_xfercomp_isoc_split_in(hsotg, chan, chnum,
+							qtd))
+				goto handle_xfercomp_done;
+		} else {
+			qtd->complete_split = 0;
+		}
+	}
+
+	/* Update the QTD and URB states */
+	switch (pipe_type) {
+	case USB_ENDPOINT_XFER_CONTROL:
+		switch (qtd->control_phase) {
+		case DWC2_CONTROL_SETUP:
+			if (urb->length > 0)
+				qtd->control_phase = DWC2_CONTROL_DATA;
+			else
+				qtd->control_phase = DWC2_CONTROL_STATUS;
+			dev_vdbg(hsotg->dev,
+				 "  Control setup transaction done\n");
+			halt_status = DWC2_HC_XFER_COMPLETE;
+			break;
+		case DWC2_CONTROL_DATA:
+			urb_xfer_done = dwc2_update_urb_state(hsotg, chan,
+							      chnum, urb, qtd);
+			if (urb_xfer_done) {
+				qtd->control_phase = DWC2_CONTROL_STATUS;
+				dev_vdbg(hsotg->dev,
+					 "  Control data transfer done\n");
+			} else {
+				dwc2_hcd_save_data_toggle(hsotg, chan, chnum,
+							  qtd);
+			}
+			halt_status = DWC2_HC_XFER_COMPLETE;
+			break;
+		case DWC2_CONTROL_STATUS:
+			dev_vdbg(hsotg->dev, "  Control transfer complete\n");
+			if (urb->status == -EINPROGRESS)
+				urb->status = 0;
+			dwc2_host_complete(hsotg, qtd, urb->status);
+			halt_status = DWC2_HC_XFER_URB_COMPLETE;
+			break;
+		}
+
+		dwc2_complete_non_periodic_xfer(hsotg, chan, chnum, qtd,
+						halt_status);
+		break;
+	case USB_ENDPOINT_XFER_BULK:
+		dev_vdbg(hsotg->dev, "  Bulk transfer complete\n");
+		urb_xfer_done = dwc2_update_urb_state(hsotg, chan, chnum, urb,
+						      qtd);
+		if (urb_xfer_done) {
+			dwc2_host_complete(hsotg, qtd, urb->status);
+			halt_status = DWC2_HC_XFER_URB_COMPLETE;
+		} else {
+			halt_status = DWC2_HC_XFER_COMPLETE;
+		}
+
+		dwc2_hcd_save_data_toggle(hsotg, chan, chnum, qtd);
+		dwc2_complete_non_periodic_xfer(hsotg, chan, chnum, qtd,
+						halt_status);
+		break;
+	case USB_ENDPOINT_XFER_INT:
+		dev_vdbg(hsotg->dev, "  Interrupt transfer complete\n");
+		urb_xfer_done = dwc2_update_urb_state(hsotg, chan, chnum, urb,
+						      qtd);
+
+		/*
+		 * Interrupt URB is done on the first transfer complete
+		 * interrupt
+		 */
+		if (urb_xfer_done) {
+			dwc2_host_complete(hsotg, qtd, urb->status);
+			halt_status = DWC2_HC_XFER_URB_COMPLETE;
+		} else {
+			halt_status = DWC2_HC_XFER_COMPLETE;
+		}
+
+		dwc2_hcd_save_data_toggle(hsotg, chan, chnum, qtd);
+		dwc2_complete_periodic_xfer(hsotg, chan, chnum, qtd,
+					    halt_status);
+		break;
+	case USB_ENDPOINT_XFER_ISOC:
+		if (dbg_perio())
+			dev_vdbg(hsotg->dev, "  Isochronous transfer complete\n");
+		if (qtd->isoc_split_pos == DWC2_HCSPLT_XACTPOS_ALL)
+			halt_status = dwc2_update_isoc_urb_state(hsotg, chan,
+					chnum, qtd, DWC2_HC_XFER_COMPLETE);
+		dwc2_complete_periodic_xfer(hsotg, chan, chnum, qtd,
+					    halt_status);
+		break;
+	}
+
+handle_xfercomp_done:
+	disable_hc_int(hsotg, chnum, HCINTMSK_XFERCOMPL);
+}
+
+/*
+ * Handles a host channel STALL interrupt. This handler may be called in
+ * either DMA mode or Slave mode.
+ */
+static void dwc2_hc_stall_intr(struct dwc2_hsotg *hsotg,
+			       struct dwc2_host_chan *chan, int chnum,
+			       struct dwc2_qtd *qtd)
+{
+	struct dwc2_hcd_urb *urb = qtd->urb;
+	int pipe_type;
+
+	dev_dbg(hsotg->dev, "--Host Channel %d Interrupt: STALL Received--\n",
+		chnum);
+
+	if (hsotg->core_params->dma_desc_enable > 0) {
+		dwc2_hcd_complete_xfer_ddma(hsotg, chan, chnum,
+					    DWC2_HC_XFER_STALL);
+		goto handle_stall_done;
+	}
+
+	if (!urb)
+		goto handle_stall_halt;
+
+	pipe_type = dwc2_hcd_get_pipe_type(&urb->pipe_info);
+
+	if (pipe_type == USB_ENDPOINT_XFER_CONTROL)
+		dwc2_host_complete(hsotg, qtd, -EPIPE);
+
+	if (pipe_type == USB_ENDPOINT_XFER_BULK ||
+	    pipe_type == USB_ENDPOINT_XFER_INT) {
+		dwc2_host_complete(hsotg, qtd, -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.
+		 */
+		chan->qh->data_toggle = 0;
+	}
+
+handle_stall_halt:
+	dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_STALL);
+
+handle_stall_done:
+	disable_hc_int(hsotg, chnum, HCINTMSK_STALL);
+}
+
+/*
+ * 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 dwc2_update_urb_state_abn(struct dwc2_hsotg *hsotg,
+				      struct dwc2_host_chan *chan, int chnum,
+				      struct dwc2_hcd_urb *urb,
+				      struct dwc2_qtd *qtd,
+				      enum dwc2_halt_status halt_status)
+{
+	u32 xfer_length = dwc2_get_actual_xfer_length(hsotg, chan, chnum,
+						      qtd, halt_status, NULL);
+	u32 hctsiz;
+
+	if (urb->actual_length + xfer_length > urb->length) {
+		dev_warn(hsotg->dev, "%s(): trimming xfer length\n", __func__);
+		xfer_length = urb->length - urb->actual_length;
+	}
+
+	/* Non DWORD-aligned buffer case handling */
+	if (chan->align_buf && xfer_length && chan->ep_is_in) {
+		dev_vdbg(hsotg->dev, "%s(): non-aligned buffer\n", __func__);
+		memcpy(urb->buf + urb->actual_length, chan->qh->dw_align_buf,
+		       xfer_length);
+	}
+
+	urb->actual_length += xfer_length;
+
+	hctsiz = readl(hsotg->regs + HCTSIZ(chnum));
+	dev_vdbg(hsotg->dev, "DWC_otg: %s: %s, channel %d\n",
+		 __func__, (chan->ep_is_in ? "IN" : "OUT"), chnum);
+	dev_vdbg(hsotg->dev, "  chan->start_pkt_count %d\n",
+		 chan->start_pkt_count);
+	dev_vdbg(hsotg->dev, "  hctsiz.pktcnt %d\n",
+		 (hctsiz & TSIZ_PKTCNT_MASK) >> TSIZ_PKTCNT_SHIFT);
+	dev_vdbg(hsotg->dev, "  chan->max_packet %d\n", chan->max_packet);
+	dev_vdbg(hsotg->dev, "  bytes_transferred %d\n",
+		 xfer_length);
+	dev_vdbg(hsotg->dev, "  urb->actual_length %d\n",
+		 urb->actual_length);
+	dev_vdbg(hsotg->dev, "  urb->transfer_buffer_length %d\n",
+		 urb->length);
+}
+
+/*
+ * Handles a host channel NAK interrupt. This handler may be called in either
+ * DMA mode or Slave mode.
+ */
+static void dwc2_hc_nak_intr(struct dwc2_hsotg *hsotg,
+			     struct dwc2_host_chan *chan, int chnum,
+			     struct dwc2_qtd *qtd)
+{
+	if (dbg_hc(chan))
+		dev_vdbg(hsotg->dev, "--Host Channel %d Interrupt: NAK Received--\n",
+			 chnum);
+
+	/*
+	 * Handle NAK for IN/OUT SSPLIT/CSPLIT transfers, bulk, control, and
+	 * interrupt. Re-start the SSPLIT transfer.
+	 */
+	if (chan->do_split) {
+		if (chan->complete_split)
+			qtd->error_count = 0;
+		qtd->complete_split = 0;
+		dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_NAK);
+		goto handle_nak_done;
+	}
+
+	switch (dwc2_hcd_get_pipe_type(&qtd->urb->pipe_info)) {
+	case USB_ENDPOINT_XFER_CONTROL:
+	case USB_ENDPOINT_XFER_BULK:
+		if (hsotg->core_params->dma_enable > 0 && chan->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;
+			break;
+		}
+
+		/*
+		 * 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 (!chan->qh->ping_state) {
+			dwc2_update_urb_state_abn(hsotg, chan, chnum, qtd->urb,
+						  qtd, DWC2_HC_XFER_NAK);
+			dwc2_hcd_save_data_toggle(hsotg, chan, chnum, qtd);
+
+			if (chan->speed == USB_SPEED_HIGH)
+				chan->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
+		 */
+		dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_NAK);
+		break;
+	case USB_ENDPOINT_XFER_INT:
+		qtd->error_count = 0;
+		dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_NAK);
+		break;
+	case USB_ENDPOINT_XFER_ISOC:
+		/* Should never get called for isochronous transfers */
+		dev_err(hsotg->dev, "NACK interrupt for ISOC transfer\n");
+		break;
+	}
+
+handle_nak_done:
+	disable_hc_int(hsotg, chnum, HCINTMSK_NAK);
+}
+
+/*
+ * 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 void dwc2_hc_ack_intr(struct dwc2_hsotg *hsotg,
+			     struct dwc2_host_chan *chan, int chnum,
+			     struct dwc2_qtd *qtd)
+{
+	struct dwc2_hcd_iso_packet_desc *frame_desc;
+
+	if (dbg_hc(chan))
+		dev_vdbg(hsotg->dev, "--Host Channel %d Interrupt: ACK Received--\n",
+			 chnum);
+
+	if (chan->do_split) {
+		/* Handle ACK on SSPLIT. ACK should not occur in CSPLIT. */
+		if (!chan->ep_is_in &&
+		    chan->data_pid_start != DWC2_HC_PID_SETUP)
+			qtd->ssplit_out_xfer_count = chan->xfer_len;
+
+		if (chan->ep_type != USB_ENDPOINT_XFER_ISOC || chan->ep_is_in) {
+			qtd->complete_split = 1;
+			dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_ACK);
+		} else {
+			/* ISOC OUT */
+			switch (chan->xact_pos) {
+			case DWC2_HCSPLT_XACTPOS_ALL:
+				break;
+			case DWC2_HCSPLT_XACTPOS_END:
+				qtd->isoc_split_pos = DWC2_HCSPLT_XACTPOS_ALL;
+				qtd->isoc_split_offset = 0;
+				break;
+			case DWC2_HCSPLT_XACTPOS_BEGIN:
+			case DWC2_HCSPLT_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_descs[
+						qtd->isoc_frame_index];
+				qtd->isoc_split_offset += 188;
+
+				if (frame_desc->length - qtd->isoc_split_offset
+							<= 188)
+					qtd->isoc_split_pos =
+							DWC2_HCSPLT_XACTPOS_END;
+				else
+					qtd->isoc_split_pos =
+							DWC2_HCSPLT_XACTPOS_MID;
+				break;
+			}
+		}
+	} else {
+		qtd->error_count = 0;
+
+		if (chan->qh->ping_state) {
+			chan->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.
+			 */
+			dwc2_halt_channel(hsotg, chan, qtd, DWC2_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_hc_int(hsotg, chnum, HCINTMSK_ACK);
+}
+
+/*
+ * 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 void dwc2_hc_nyet_intr(struct dwc2_hsotg *hsotg,
+			      struct dwc2_host_chan *chan, int chnum,
+			      struct dwc2_qtd *qtd)
+{
+	if (dbg_hc(chan))
+		dev_vdbg(hsotg->dev, "--Host Channel %d Interrupt: NYET Received--\n",
+			 chnum);
+
+	/*
+	 * NYET on CSPLIT
+	 * re-do the CSPLIT immediately on non-periodic
+	 */
+	if (chan->do_split && chan->complete_split) {
+		if (chan->ep_is_in && chan->ep_type == USB_ENDPOINT_XFER_ISOC &&
+		    hsotg->core_params->dma_enable > 0) {
+			qtd->complete_split = 0;
+			qtd->isoc_split_offset = 0;
+			qtd->isoc_frame_index++;
+			if (qtd->urb &&
+			    qtd->isoc_frame_index == qtd->urb->packet_count) {
+				dwc2_host_complete(hsotg, qtd, 0);
+				dwc2_release_channel(hsotg, chan, qtd,
+						     DWC2_HC_XFER_URB_COMPLETE);
+			} else {
+				dwc2_release_channel(hsotg, chan, qtd,
+						DWC2_HC_XFER_NO_HALT_STATUS);
+			}
+			goto handle_nyet_done;
+		}
+
+		if (chan->ep_type == USB_ENDPOINT_XFER_INT ||
+		    chan->ep_type == USB_ENDPOINT_XFER_ISOC) {
+			int frnum = dwc2_hcd_get_frame_number(hsotg);
+
+			if (dwc2_full_frame_num(frnum) !=
+			    dwc2_full_frame_num(chan->qh->sched_frame)) {
+				/*
+				 * No longer in the same full speed frame.
+				 * Treat this as a transaction error.
+				 */
+#if 0
+				/*
+				 * Todo: Fix system performance so this can
+				 * be treated as an error. Right now complete
+				 * splits cannot be scheduled precisely enough
+				 * due to other system activity, so this error
+				 * occurs regularly in Slave mode.
+				 */
+				qtd->error_count++;
+#endif
+				qtd->complete_split = 0;
+				dwc2_halt_channel(hsotg, chan, qtd,
+						  DWC2_HC_XFER_XACT_ERR);
+				/* Todo: add support for isoc release */
+				goto handle_nyet_done;
+			}
+		}
+
+		dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_NYET);
+		goto handle_nyet_done;
+	}
+
+	chan->qh->ping_state = 1;
+	qtd->error_count = 0;
+
+	dwc2_update_urb_state_abn(hsotg, chan, chnum, qtd->urb, qtd,
+				  DWC2_HC_XFER_NYET);
+	dwc2_hcd_save_data_toggle(hsotg, chan, chnum, qtd);
+
+	/*
+	 * Halt the channel and re-start the transfer so the PING protocol
+	 * will start
+	 */
+	dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_NYET);
+
+handle_nyet_done:
+	disable_hc_int(hsotg, chnum, HCINTMSK_NYET);
+}
+
+/*
+ * Handles a host channel babble interrupt. This handler may be called in
+ * either DMA mode or Slave mode.
+ */
+static void dwc2_hc_babble_intr(struct dwc2_hsotg *hsotg,
+				struct dwc2_host_chan *chan, int chnum,
+				struct dwc2_qtd *qtd)
+{
+	dev_dbg(hsotg->dev, "--Host Channel %d Interrupt: Babble Error--\n",
+		chnum);
+
+	dwc2_hc_handle_tt_clear(hsotg, chan, qtd);
+
+	if (hsotg->core_params->dma_desc_enable > 0) {
+		dwc2_hcd_complete_xfer_ddma(hsotg, chan, chnum,
+					    DWC2_HC_XFER_BABBLE_ERR);
+		goto disable_int;
+	}
+
+	if (chan->ep_type != USB_ENDPOINT_XFER_ISOC) {
+		dwc2_host_complete(hsotg, qtd, -EOVERFLOW);
+		dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_BABBLE_ERR);
+	} else {
+		enum dwc2_halt_status halt_status;
+
+		halt_status = dwc2_update_isoc_urb_state(hsotg, chan, chnum,
+						qtd, DWC2_HC_XFER_BABBLE_ERR);
+		dwc2_halt_channel(hsotg, chan, qtd, halt_status);
+	}
+
+disable_int:
+	disable_hc_int(hsotg, chnum, HCINTMSK_BBLERR);
+}
+
+/*
+ * Handles a host channel AHB error interrupt. This handler is only called in
+ * DMA mode.
+ */
+static void dwc2_hc_ahberr_intr(struct dwc2_hsotg *hsotg,
+				struct dwc2_host_chan *chan, int chnum,
+				struct dwc2_qtd *qtd)
+{
+	struct dwc2_hcd_urb *urb = qtd->urb;
+	char *pipetype, *speed;
+	u32 hcchar;
+	u32 hcsplt;
+	u32 hctsiz;
+	u32 hc_dma;
+
+	dev_dbg(hsotg->dev, "--Host Channel %d Interrupt: AHB Error--\n",
+		chnum);
+
+	if (!urb)
+		goto handle_ahberr_halt;
+
+	dwc2_hc_handle_tt_clear(hsotg, chan, qtd);
+
+	hcchar = readl(hsotg->regs + HCCHAR(chnum));
+	hcsplt = readl(hsotg->regs + HCSPLT(chnum));
+	hctsiz = readl(hsotg->regs + HCTSIZ(chnum));
+	hc_dma = readl(hsotg->regs + HCDMA(chnum));
+
+	dev_err(hsotg->dev, "AHB ERROR, Channel %d\n", chnum);
+	dev_err(hsotg->dev, "  hcchar 0x%08x, hcsplt 0x%08x\n", hcchar, hcsplt);
+	dev_err(hsotg->dev, "  hctsiz 0x%08x, hc_dma 0x%08x\n", hctsiz, hc_dma);
+	dev_err(hsotg->dev, "  Device address: %d\n",
+		dwc2_hcd_get_dev_addr(&urb->pipe_info));
+	dev_err(hsotg->dev, "  Endpoint: %d, %s\n",
+		dwc2_hcd_get_ep_num(&urb->pipe_info),
+		dwc2_hcd_is_pipe_in(&urb->pipe_info) ? "IN" : "OUT");
+
+	switch (dwc2_hcd_get_pipe_type(&urb->pipe_info)) {
+	case USB_ENDPOINT_XFER_CONTROL:
+		pipetype = "CONTROL";
+		break;
+	case USB_ENDPOINT_XFER_BULK:
+		pipetype = "BULK";
+		break;
+	case USB_ENDPOINT_XFER_INT:
+		pipetype = "INTERRUPT";
+		break;
+	case USB_ENDPOINT_XFER_ISOC:
+		pipetype = "ISOCHRONOUS";
+		break;
+	default:
+		pipetype = "UNKNOWN";
+		break;
+	}
+
+	dev_err(hsotg->dev, "  Endpoint type: %s\n", pipetype);
+
+	switch (chan->speed) {
+	case USB_SPEED_HIGH:
+		speed = "HIGH";
+		break;
+	case USB_SPEED_FULL:
+		speed = "FULL";
+		break;
+	case USB_SPEED_LOW:
+		speed = "LOW";
+		break;
+	default:
+		speed = "UNKNOWN";
+		break;
+	}
+
+	dev_err(hsotg->dev, "  Speed: %s\n", speed);
+
+	dev_err(hsotg->dev, "  Max packet size: %d\n",
+		dwc2_hcd_get_mps(&urb->pipe_info));
+	dev_err(hsotg->dev, "  Data buffer length: %d\n", urb->length);
+	dev_err(hsotg->dev, "  Transfer buffer: %p, Transfer DMA: %08lx\n",
+		urb->buf, (unsigned long)urb->dma);
+	dev_err(hsotg->dev, "  Setup buffer: %p, Setup DMA: %08lx\n",
+		urb->setup_packet, (unsigned long)urb->setup_dma);
+	dev_err(hsotg->dev, "  Interval: %d\n", urb->interval);
+
+	/* Core halts the channel for Descriptor DMA mode */
+	if (hsotg->core_params->dma_desc_enable > 0) {
+		dwc2_hcd_complete_xfer_ddma(hsotg, chan, chnum,
+					    DWC2_HC_XFER_AHB_ERR);
+		goto handle_ahberr_done;
+	}
+
+	dwc2_host_complete(hsotg, qtd, -EIO);
+
+handle_ahberr_halt:
+	/*
+	 * Force a channel halt. Don't call dwc2_halt_channel because that won't
+	 * write to the HCCHARn register in DMA mode to force the halt.
+	 */
+	dwc2_hc_halt(hsotg, chan, DWC2_HC_XFER_AHB_ERR);
+
+handle_ahberr_done:
+	disable_hc_int(hsotg, chnum, HCINTMSK_AHBERR);
+}
+
+/*
+ * Handles a host channel transaction error interrupt. This handler may be
+ * called in either DMA mode or Slave mode.
+ */
+static void dwc2_hc_xacterr_intr(struct dwc2_hsotg *hsotg,
+				 struct dwc2_host_chan *chan, int chnum,
+				 struct dwc2_qtd *qtd)
+{
+	dev_dbg(hsotg->dev,
+		"--Host Channel %d Interrupt: Transaction Error--\n", chnum);
+
+	dwc2_hc_handle_tt_clear(hsotg, chan, qtd);
+
+	if (hsotg->core_params->dma_desc_enable > 0) {
+		dwc2_hcd_complete_xfer_ddma(hsotg, chan, chnum,
+					    DWC2_HC_XFER_XACT_ERR);
+		goto handle_xacterr_done;
+	}
+
+	switch (dwc2_hcd_get_pipe_type(&qtd->urb->pipe_info)) {
+	case USB_ENDPOINT_XFER_CONTROL:
+	case USB_ENDPOINT_XFER_BULK:
+		qtd->error_count++;
+		if (!chan->qh->ping_state) {
+
+			dwc2_update_urb_state_abn(hsotg, chan, chnum, qtd->urb,
+						  qtd, DWC2_HC_XFER_XACT_ERR);
+			dwc2_hcd_save_data_toggle(hsotg, chan, chnum, qtd);
+			if (!chan->ep_is_in && chan->speed == USB_SPEED_HIGH)
+				chan->qh->ping_state = 1;
+		}
+
+		/*
+		 * Halt the channel so the transfer can be re-started from
+		 * the appropriate point or the PING protocol will start
+		 */
+		dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_XACT_ERR);
+		break;
+	case USB_ENDPOINT_XFER_INT:
+		qtd->error_count++;
+		if (chan->do_split && chan->complete_split)
+			qtd->complete_split = 0;
+		dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_XACT_ERR);
+		break;
+	case USB_ENDPOINT_XFER_ISOC:
+		{
+			enum dwc2_halt_status halt_status;
+
+			halt_status = dwc2_update_isoc_urb_state(hsotg, chan,
+					chnum, qtd, DWC2_HC_XFER_XACT_ERR);
+			dwc2_halt_channel(hsotg, chan, qtd, halt_status);
+		}
+		break;
+	}
+
+handle_xacterr_done:
+	disable_hc_int(hsotg, chnum, HCINTMSK_XACTERR);
+}
+
+/*
+ * Handles a host channel frame overrun interrupt. This handler may be called
+ * in either DMA mode or Slave mode.
+ */
+static void dwc2_hc_frmovrun_intr(struct dwc2_hsotg *hsotg,
+				  struct dwc2_host_chan *chan, int chnum,
+				  struct dwc2_qtd *qtd)
+{
+	enum dwc2_halt_status halt_status;
+
+	if (dbg_hc(chan))
+		dev_dbg(hsotg->dev, "--Host Channel %d Interrupt: Frame Overrun--\n",
+			chnum);
+
+	dwc2_hc_handle_tt_clear(hsotg, chan, qtd);
+
+	switch (dwc2_hcd_get_pipe_type(&qtd->urb->pipe_info)) {
+	case USB_ENDPOINT_XFER_CONTROL:
+	case USB_ENDPOINT_XFER_BULK:
+		break;
+	case USB_ENDPOINT_XFER_INT:
+		dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_FRAME_OVERRUN);
+		break;
+	case USB_ENDPOINT_XFER_ISOC:
+		halt_status = dwc2_update_isoc_urb_state(hsotg, chan, chnum,
+					qtd, DWC2_HC_XFER_FRAME_OVERRUN);
+		dwc2_halt_channel(hsotg, chan, qtd, halt_status);
+		break;
+	}
+
+	disable_hc_int(hsotg, chnum, HCINTMSK_FRMOVRUN);
+}
+
+/*
+ * Handles a host channel data toggle error interrupt. This handler may be
+ * called in either DMA mode or Slave mode.
+ */
+static void dwc2_hc_datatglerr_intr(struct dwc2_hsotg *hsotg,
+				    struct dwc2_host_chan *chan, int chnum,
+				    struct dwc2_qtd *qtd)
+{
+	dev_dbg(hsotg->dev,
+		"--Host Channel %d Interrupt: Data Toggle Error--\n", chnum);
+
+	if (chan->ep_is_in)
+		qtd->error_count = 0;
+	else
+		dev_err(hsotg->dev,
+			"Data Toggle Error on OUT transfer, channel %d\n",
+			chnum);
+
+	dwc2_hc_handle_tt_clear(hsotg, chan, qtd);
+	disable_hc_int(hsotg, chnum, HCINTMSK_DATATGLERR);
+}
+
+/*
+ * For debug only. It checks that a valid halt status is set and that
+ * HCCHARn.chdis is clear. If there's a problem, corrective action is
+ * taken and a warning is issued.
+ *
+ * Return: true if halt status is ok, false otherwise
+ */
+static bool dwc2_halt_status_ok(struct dwc2_hsotg *hsotg,
+				struct dwc2_host_chan *chan, int chnum,
+				struct dwc2_qtd *qtd)
+{
+#ifdef DEBUG
+	u32 hcchar;
+	u32 hctsiz;
+	u32 hcintmsk;
+	u32 hcsplt;
+
+	if (chan->halt_status == DWC2_HC_XFER_NO_HALT_STATUS) {
+		/*
+		 * This code is here only as a check. This condition should
+		 * never happen. Ignore the halt if it does occur.
+		 */
+		hcchar = readl(hsotg->regs + HCCHAR(chnum));
+		hctsiz = readl(hsotg->regs + HCTSIZ(chnum));
+		hcintmsk = readl(hsotg->regs + HCINTMSK(chnum));
+		hcsplt = readl(hsotg->regs + HCSPLT(chnum));
+		dev_dbg(hsotg->dev,
+			"%s: chan->halt_status DWC2_HC_XFER_NO_HALT_STATUS,\n",
+			 __func__);
+		dev_dbg(hsotg->dev,
+			"channel %d, hcchar 0x%08x, hctsiz 0x%08x,\n",
+			chnum, hcchar, hctsiz);
+		dev_dbg(hsotg->dev,
+			"hcint 0x%08x, hcintmsk 0x%08x, hcsplt 0x%08x,\n",
+			chan->hcint, hcintmsk, hcsplt);
+		if (qtd)
+			dev_dbg(hsotg->dev, "qtd->complete_split %d\n",
+				qtd->complete_split);
+		dev_warn(hsotg->dev,
+			 "%s: no halt status, channel %d, ignoring interrupt\n",
+			 __func__, chnum);
+		return false;
+	}
+
+	/*
+	 * This code is here only as a check. hcchar.chdis should never be set
+	 * when the halt interrupt occurs. Halt the channel again if it does
+	 * occur.
+	 */
+	hcchar = readl(hsotg->regs + HCCHAR(chnum));
+	if (hcchar & HCCHAR_CHDIS) {
+		dev_warn(hsotg->dev,
+			 "%s: hcchar.chdis set unexpectedly, hcchar 0x%08x, trying to halt again\n",
+			 __func__, hcchar);
+		chan->halt_pending = 0;
+		dwc2_halt_channel(hsotg, chan, qtd, chan->halt_status);
+		return false;
+	}
+#endif
+
+	return true;
+}
+
+/*
+ * Handles a host Channel Halted interrupt in DMA mode. This handler
+ * determines the reason the channel halted and proceeds accordingly.
+ */
+static void dwc2_hc_chhltd_intr_dma(struct dwc2_hsotg *hsotg,
+				    struct dwc2_host_chan *chan, int chnum,
+				    struct dwc2_qtd *qtd)
+{
+	u32 hcintmsk;
+	int out_nak_enh = 0;
+
+	if (dbg_hc(chan))
+		dev_vdbg(hsotg->dev,
+			 "--Host Channel %d Interrupt: DMA Channel Halted--\n",
+			 chnum);
+
+	/*
+	 * For core with OUT NAK enhancement, the flow for high-speed
+	 * CONTROL/BULK OUT is handled a little differently
+	 */
+	if (hsotg->hw_params.snpsid >= DWC2_CORE_REV_2_71a) {
+		if (chan->speed == USB_SPEED_HIGH && !chan->ep_is_in &&
+		    (chan->ep_type == USB_ENDPOINT_XFER_CONTROL ||
+		     chan->ep_type == USB_ENDPOINT_XFER_BULK)) {
+			out_nak_enh = 1;
+		}
+	}
+
+	if (chan->halt_status == DWC2_HC_XFER_URB_DEQUEUE ||
+	    (chan->halt_status == DWC2_HC_XFER_AHB_ERR &&
+	     hsotg->core_params->dma_desc_enable <= 0)) {
+		if (hsotg->core_params->dma_desc_enable > 0)
+			dwc2_hcd_complete_xfer_ddma(hsotg, chan, chnum,
+						    chan->halt_status);
+		else
+			/*
+			 * 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.
+			 */
+			dwc2_release_channel(hsotg, chan, qtd,
+					     chan->halt_status);
+		return;
+	}
+
+	hcintmsk = readl(hsotg->regs + HCINTMSK(chnum));
+
+	if (chan->hcint & HCINTMSK_XFERCOMPL) {
+		/*
+		 * Todo: 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 (chan->ep_type == USB_ENDPOINT_XFER_ISOC && !chan->ep_is_in)
+			dwc2_hc_ack_intr(hsotg, chan, chnum, qtd);
+		dwc2_hc_xfercomp_intr(hsotg, chan, chnum, qtd);
+	} else if (chan->hcint & HCINTMSK_STALL) {
+		dwc2_hc_stall_intr(hsotg, chan, chnum, qtd);
+	} else if ((chan->hcint & HCINTMSK_XACTERR) &&
+		   hsotg->core_params->dma_desc_enable <= 0) {
+		if (out_nak_enh) {
+			if (chan->hcint &
+			    (HCINTMSK_NYET | HCINTMSK_NAK | HCINTMSK_ACK)) {
+				dev_vdbg(hsotg->dev,
+					 "XactErr with NYET/NAK/ACK\n");
+				qtd->error_count = 0;
+			} else {
+				dev_vdbg(hsotg->dev,
+					 "XactErr without NYET/NAK/ACK\n");
+			}
+		}
+
+		/*
+		 * 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.
+		 */
+		dwc2_hc_xacterr_intr(hsotg, chan, chnum, qtd);
+	} else if ((chan->hcint & HCINTMSK_XCS_XACT) &&
+		   hsotg->core_params->dma_desc_enable > 0) {
+		dwc2_hc_xacterr_intr(hsotg, chan, chnum, qtd);
+	} else if ((chan->hcint & HCINTMSK_AHBERR) &&
+		   hsotg->core_params->dma_desc_enable > 0) {
+		dwc2_hc_ahberr_intr(hsotg, chan, chnum, qtd);
+	} else if (chan->hcint & HCINTMSK_BBLERR) {
+		dwc2_hc_babble_intr(hsotg, chan, chnum, qtd);
+	} else if (chan->hcint & HCINTMSK_FRMOVRUN) {
+		dwc2_hc_frmovrun_intr(hsotg, chan, chnum, qtd);
+	} else if (!out_nak_enh) {
+		if (chan->hcint & HCINTMSK_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.
+			 */
+			dwc2_hc_nyet_intr(hsotg, chan, chnum, qtd);
+		} else if ((chan->hcint & HCINTMSK_NAK) &&
+			   !(hcintmsk & HCINTMSK_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.
+			 */
+			dwc2_hc_nak_intr(hsotg, chan, chnum, qtd);
+		} else if ((chan->hcint & HCINTMSK_ACK) &&
+			   !(hcintmsk & HCINTMSK_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.
+			 */
+			dwc2_hc_ack_intr(hsotg, chan, chnum, qtd);
+		} else {
+			if (chan->ep_type == USB_ENDPOINT_XFER_INT ||
+			    chan->ep_type == USB_ENDPOINT_XFER_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.
+				 */
+				dev_dbg(hsotg->dev,
+					"%s: Halt channel %d (assume incomplete periodic transfer)\n",
+					__func__, chnum);
+				dwc2_halt_channel(hsotg, chan, qtd,
+					DWC2_HC_XFER_PERIODIC_INCOMPLETE);
+			} else {
+				dev_err(hsotg->dev,
+					"%s: Channel %d - ChHltd set, but reason is unknown\n",
+					__func__, chnum);
+				dev_err(hsotg->dev,
+					"hcint 0x%08x, intsts 0x%08x\n",
+					chan->hcint,
+					readl(hsotg->regs + GINTSTS));
+				goto error;
+			}
+		}
+	} else {
+		dev_info(hsotg->dev,
+			 "NYET/NAK/ACK/other in non-error case, 0x%08x\n",
+			 chan->hcint);
+error:
+		/* Failthrough: use 3-strikes rule */
+		qtd->error_count++;
+		dwc2_update_urb_state_abn(hsotg, chan, chnum, qtd->urb,
+					  qtd, DWC2_HC_XFER_XACT_ERR);
+		dwc2_hcd_save_data_toggle(hsotg, chan, chnum, qtd);
+		dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_XACT_ERR);
+	}
+}
+
+/*
+ * 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 void dwc2_hc_chhltd_intr(struct dwc2_hsotg *hsotg,
+				struct dwc2_host_chan *chan, int chnum,
+				struct dwc2_qtd *qtd)
+{
+	if (dbg_hc(chan))
+		dev_vdbg(hsotg->dev, "--Host Channel %d Interrupt: Channel Halted--\n",
+			 chnum);
+
+	if (hsotg->core_params->dma_enable > 0) {
+		dwc2_hc_chhltd_intr_dma(hsotg, chan, chnum, qtd);
+	} else {
+		if (!dwc2_halt_status_ok(hsotg, chan, chnum, qtd))
+			return;
+		dwc2_release_channel(hsotg, chan, qtd, chan->halt_status);
+	}
+}
+
+/* Handles interrupt for a specific Host Channel */
+static void dwc2_hc_n_intr(struct dwc2_hsotg *hsotg, int chnum)
+{
+	struct dwc2_qtd *qtd;
+	struct dwc2_host_chan *chan;
+	u32 hcint, hcintmsk;
+
+	chan = hsotg->hc_ptr_array[chnum];
+
+	hcint = readl(hsotg->regs + HCINT(chnum));
+	hcintmsk = readl(hsotg->regs + HCINTMSK(chnum));
+	if (!chan) {
+		dev_err(hsotg->dev, "## hc_ptr_array for channel is NULL ##\n");
+		writel(hcint, hsotg->regs + HCINT(chnum));
+		return;
+	}
+
+	if (dbg_hc(chan)) {
+		dev_vdbg(hsotg->dev, "--Host Channel Interrupt--, Channel %d\n",
+			 chnum);
+		dev_vdbg(hsotg->dev,
+			 "  hcint 0x%08x, hcintmsk 0x%08x, hcint&hcintmsk 0x%08x\n",
+			 hcint, hcintmsk, hcint & hcintmsk);
+	}
+
+	writel(hcint, hsotg->regs + HCINT(chnum));
+	chan->hcint = hcint;
+	hcint &= hcintmsk;
+
+	/*
+	 * If the channel was halted due to a dequeue, the qtd list might
+	 * be empty or at least the first entry will not be the active qtd.
+	 * In this case, take a shortcut and just release the channel.
+	 */
+	if (chan->halt_status == DWC2_HC_XFER_URB_DEQUEUE) {
+		/*
+		 * If the channel was halted, this should be the only
+		 * interrupt unmasked
+		 */
+		WARN_ON(hcint != HCINTMSK_CHHLTD);
+		if (hsotg->core_params->dma_desc_enable > 0)
+			dwc2_hcd_complete_xfer_ddma(hsotg, chan, chnum,
+						    chan->halt_status);
+		else
+			dwc2_release_channel(hsotg, chan, NULL,
+					     chan->halt_status);
+		return;
+	}
+
+	if (list_empty(&chan->qh->qtd_list)) {
+		/*
+		 * TODO: Will this ever happen with the
+		 * DWC2_HC_XFER_URB_DEQUEUE handling above?
+		 */
+		dev_dbg(hsotg->dev, "## no QTD queued for channel %d ##\n",
+			chnum);
+		dev_dbg(hsotg->dev,
+			"  hcint 0x%08x, hcintmsk 0x%08x, hcint&hcintmsk 0x%08x\n",
+			chan->hcint, hcintmsk, hcint);
+		chan->halt_status = DWC2_HC_XFER_NO_HALT_STATUS;
+		disable_hc_int(hsotg, chnum, HCINTMSK_CHHLTD);
+		chan->hcint = 0;
+		return;
+	}
+
+	qtd = list_first_entry(&chan->qh->qtd_list, struct dwc2_qtd,
+			       qtd_list_entry);
+
+	if (hsotg->core_params->dma_enable <= 0) {
+		if ((hcint & HCINTMSK_CHHLTD) && hcint != HCINTMSK_CHHLTD)
+			hcint &= ~HCINTMSK_CHHLTD;
+	}
+
+	if (hcint & HCINTMSK_XFERCOMPL) {
+		dwc2_hc_xfercomp_intr(hsotg, chan, chnum, 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 &= ~HCINTMSK_NYET;
+	}
+	if (hcint & HCINTMSK_CHHLTD)
+		dwc2_hc_chhltd_intr(hsotg, chan, chnum, qtd);
+	if (hcint & HCINTMSK_AHBERR)
+		dwc2_hc_ahberr_intr(hsotg, chan, chnum, qtd);
+	if (hcint & HCINTMSK_STALL)
+		dwc2_hc_stall_intr(hsotg, chan, chnum, qtd);
+	if (hcint & HCINTMSK_NAK)
+		dwc2_hc_nak_intr(hsotg, chan, chnum, qtd);
+	if (hcint & HCINTMSK_ACK)
+		dwc2_hc_ack_intr(hsotg, chan, chnum, qtd);
+	if (hcint & HCINTMSK_NYET)
+		dwc2_hc_nyet_intr(hsotg, chan, chnum, qtd);
+	if (hcint & HCINTMSK_XACTERR)
+		dwc2_hc_xacterr_intr(hsotg, chan, chnum, qtd);
+	if (hcint & HCINTMSK_BBLERR)
+		dwc2_hc_babble_intr(hsotg, chan, chnum, qtd);
+	if (hcint & HCINTMSK_FRMOVRUN)
+		dwc2_hc_frmovrun_intr(hsotg, chan, chnum, qtd);
+	if (hcint & HCINTMSK_DATATGLERR)
+		dwc2_hc_datatglerr_intr(hsotg, chan, chnum, qtd);
+
+	chan->hcint = 0;
+}
+
+/*
+ * 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 void dwc2_hc_intr(struct dwc2_hsotg *hsotg)
+{
+	u32 haint;
+	int i;
+
+	haint = readl(hsotg->regs + HAINT);
+	if (dbg_perio()) {
+		dev_vdbg(hsotg->dev, "%s()\n", __func__);
+
+		dev_vdbg(hsotg->dev, "HAINT=%08x\n", haint);
+	}
+
+	for (i = 0; i < hsotg->core_params->host_channels; i++) {
+		if (haint & (1 << i))
+			dwc2_hc_n_intr(hsotg, i);
+	}
+}
+
+/* This function handles interrupts for the HCD */
+irqreturn_t dwc2_handle_hcd_intr(struct dwc2_hsotg *hsotg)
+{
+	u32 gintsts, dbg_gintsts;
+	irqreturn_t retval = IRQ_NONE;
+
+	if (!dwc2_is_controller_alive(hsotg)) {
+		dev_warn(hsotg->dev, "Controller is dead\n");
+		return retval;
+	}
+
+	spin_lock(&hsotg->lock);
+
+	/* Check if HOST Mode */
+	if (dwc2_is_host_mode(hsotg)) {
+		gintsts = dwc2_read_core_intr(hsotg);
+		if (!gintsts) {
+			spin_unlock(&hsotg->lock);
+			return retval;
+		}
+
+		retval = IRQ_HANDLED;
+
+		dbg_gintsts = gintsts;
+#ifndef DEBUG_SOF
+		dbg_gintsts &= ~GINTSTS_SOF;
+#endif
+		if (!dbg_perio())
+			dbg_gintsts &= ~(GINTSTS_HCHINT | GINTSTS_RXFLVL |
+					 GINTSTS_PTXFEMP);
+
+		/* Only print if there are any non-suppressed interrupts left */
+		if (dbg_gintsts)
+			dev_vdbg(hsotg->dev,
+				 "DWC OTG HCD Interrupt Detected gintsts&gintmsk=0x%08x\n",
+				 gintsts);
+
+		if (gintsts & GINTSTS_SOF)
+			dwc2_sof_intr(hsotg);
+		if (gintsts & GINTSTS_RXFLVL)
+			dwc2_rx_fifo_level_intr(hsotg);
+		if (gintsts & GINTSTS_NPTXFEMP)
+			dwc2_np_tx_fifo_empty_intr(hsotg);
+		if (gintsts & GINTSTS_PRTINT)
+			dwc2_port_intr(hsotg);
+		if (gintsts & GINTSTS_HCHINT)
+			dwc2_hc_intr(hsotg);
+		if (gintsts & GINTSTS_PTXFEMP)
+			dwc2_perio_tx_fifo_empty_intr(hsotg);
+
+		if (dbg_gintsts) {
+			dev_vdbg(hsotg->dev,
+				 "DWC OTG HCD Finished Servicing Interrupts\n");
+			dev_vdbg(hsotg->dev,
+				 "DWC OTG HCD gintsts=0x%08x gintmsk=0x%08x\n",
+				 readl(hsotg->regs + GINTSTS),
+				 readl(hsotg->regs + GINTMSK));
+		}
+	}
+
+	spin_unlock(&hsotg->lock);
+
+	return retval;
+}