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

Signed-off-by: Fushen Chen <fc...@apm.com>
Signed-off-by: Mark Miesfeld <mmiesf...@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 <mmiesf...@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

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