usb: pxa27x_udc: fix compiler warnings

[people/ms/u-boot.git] / drivers / usb / gadget / pxa27x_udc.c

/*
 * PXA27x USB device driver for u-boot.
 *
 * Copyright (C) 2007 Rodolfo Giometti <giometti@linux.it>
 * Copyright (C) 2007 Eurotech S.p.A.  <info@eurotech.it>
 * Copyright (C) 2008 Vivek Kutal      <vivek.kutal@azingo.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 *
 */


#include <common.h>
#include <config.h>
#include <asm/byteorder.h>
#include <usbdevice.h>
#include <asm/arch/hardware.h>
#include <asm/io.h>
#include <usb/pxa27x_udc.h>

#include "ep0.h"

/* number of endpoints on this UDC */
#define UDC_MAX_ENDPOINTS       24

static struct urb *ep0_urb;
static struct usb_device_instance *udc_device;
static int ep0state = EP0_IDLE;

#ifdef USBDDBG
static void udc_dump_buffer(char *name, u8 *buf, int len)
{
        usbdbg("%s - buf %p, len %d", name, buf, len);
        print_buffer(0, buf, 1, len, 0);
}
#else
#define udc_dump_buffer(name, buf, len)         /* void */
#endif

static inline void udc_ack_int_UDCCR(int mask)
{
        writel(readl(USIR1) | mask, USIR1);
}

/*
 * If the endpoint has an active tx_urb, then the next packet of data from the
 * URB is written to the tx FIFO.
 * The total amount of data in the urb is given by urb->actual_length.
 * The maximum amount of data that can be sent in any one packet is given by
 * endpoint->tx_packetSize.
 * The number of data bytes from this URB that have already been transmitted
 * is given by endpoint->sent.
 * endpoint->last is updated by this routine with the number of data bytes
 * transmitted in this packet.
 */
static int udc_write_urb(struct usb_endpoint_instance *endpoint)
{
        struct urb *urb = endpoint->tx_urb;
        int ep_num = endpoint->endpoint_address & USB_ENDPOINT_NUMBER_MASK;
        u32 *data32 = (u32 *) urb->buffer;
        u8  *data8 = (u8 *) urb->buffer;
        unsigned int i, n, w, b, is_short;
        int timeout = 2000;     /* 2ms */

        if (!urb || !urb->actual_length)
                return -1;

        n = MIN(urb->actual_length - endpoint->sent, endpoint->tx_packetSize);
        if (n <= 0)
                return -1;

        usbdbg("write urb on ep %d", ep_num);
#if defined(USBDDBG) && defined(USBDPARANOIA)
        usbdbg("urb: buf %p, buf_len %d, actual_len %d",
                urb->buffer, urb->buffer_length, urb->actual_length);
        usbdbg("endpoint: sent %d, tx_packetSize %d, last %d",
                endpoint->sent, endpoint->tx_packetSize, endpoint->last);
#endif

        is_short = n != endpoint->tx_packetSize;
        w = n / 4;
        b = n % 4;
        usbdbg("n %d%s w %d b %d", n, is_short ? "-s" : "", w, b);
        udc_dump_buffer("urb write", data8 + endpoint->sent, n);

        /* Prepare for data send */
        if (ep_num)
                writel(UDCCSR_PC ,UDCCSN(ep_num));

        for (i = 0; i < w; i++)
                  writel(data32[endpoint->sent / 4 + i], UDCDN(ep_num));

        for (i = 0; i < b; i++)
                  writeb(data8[endpoint->sent + w * 4 + i], UDCDN(ep_num));

        /* Set "Packet Complete" if less data then tx_packetSize */
        if (is_short)
                writel(ep_num ? UDCCSR_SP : UDCCSR0_IPR, UDCCSN(ep_num));

        /* Wait for data sent */
        if (ep_num) {
                while (!(readl(UDCCSN(ep_num)) & UDCCSR_PC)) {
                        if (timeout-- == 0)
                                return -1;
                        else
                                udelay(1);
                }
        }

        endpoint->last = n;

        if (ep_num) {
                usbd_tx_complete(endpoint);
        } else {
                endpoint->sent += n;
                endpoint->last -= n;
        }

        if (endpoint->sent >= urb->actual_length) {
                urb->actual_length = 0;
                endpoint->sent = 0;
                endpoint->last = 0;
        }

        if ((endpoint->sent >= urb->actual_length) && (!ep_num)) {
                usbdbg("ep0 IN stage done");
                if (is_short)
                        ep0state = EP0_IDLE;
                else
                        ep0state = EP0_XFER_COMPLETE;
        }

        return 0;
}

static int udc_read_urb(struct usb_endpoint_instance *endpoint)
{
        struct urb *urb = endpoint->rcv_urb;
        int ep_num = endpoint->endpoint_address & USB_ENDPOINT_NUMBER_MASK;
        u32 *data32 = (u32 *) urb->buffer;
        unsigned int i, n;

        usbdbg("read urb on ep %d", ep_num);
#if defined(USBDDBG) && defined(USBDPARANOIA)
        usbdbg("urb: buf %p, buf_len %d, actual_len %d",
                urb->buffer, urb->buffer_length, urb->actual_length);
        usbdbg("endpoint: rcv_packetSize %d",
                endpoint->rcv_packetSize);
#endif

        if (readl(UDCCSN(ep_num)) & UDCCSR_BNE)
                n = readl(UDCBCN(ep_num)) & 0x3ff;
        else /* zlp */
                n = 0;

        usbdbg("n %d%s", n, n != endpoint->rcv_packetSize ? "-s" : "");
        for (i = 0; i < n; i += 4)
                data32[urb->actual_length / 4 + i / 4] = readl(UDCDN(ep_num));

        udc_dump_buffer("urb read", (u8 *) data32, urb->actual_length + n);
        usbd_rcv_complete(endpoint, n, 0);

        return 0;
}

static int udc_read_urb_ep0(void)
{
        u32 *data32 = (u32 *) ep0_urb->buffer;
        u8 *data8 = (u8 *) ep0_urb->buffer;
        unsigned int i, n, w, b;

        usbdbg("read urb on ep 0");
#if defined(USBDDBG) && defined(USBDPARANOIA)
        usbdbg("urb: buf %p, buf_len %d, actual_len %d",
                ep0_urb->buffer, ep0_urb->buffer_length, ep0_urb->actual_length);
#endif

        n = readl(UDCBCR0);
        w = n / 4;
        b = n % 4;

        for (i = 0; i < w; i++) {
                data32[ep0_urb->actual_length / 4 + i] = readl(UDCDN(0));
                /* ep0_urb->actual_length += 4; */
        }

        for (i = 0; i < b; i++) {
                data8[ep0_urb->actual_length + w * 4 + i] = readb(UDCDN(0));
                /* ep0_urb->actual_length++; */
        }

        ep0_urb->actual_length += n;

        udc_dump_buffer("urb read", (u8 *) data32, ep0_urb->actual_length);

        writel(UDCCSR0_OPC | UDCCSR0_IPR, UDCCSR0);
        if (ep0_urb->actual_length == ep0_urb->device_request.wLength)
                return 1;

        return 0;
}

static void udc_handle_ep0(struct usb_endpoint_instance *endpoint)
{
        u32 udccsr0 = readl(UDCCSR0);
        u32 *data = (u32 *) &ep0_urb->device_request;
        int i;

        usbdbg("udccsr0 %x", udccsr0);

        /* Clear stall status */
        if (udccsr0 & UDCCSR0_SST) {
                usberr("clear stall status");
                writel(UDCCSR0_SST, UDCCSR0);
                ep0state = EP0_IDLE;
        }

        /* previous request unfinished?  non-error iff back-to-back ... */
        if ((udccsr0 & UDCCSR0_SA) != 0 && ep0state != EP0_IDLE)
                ep0state = EP0_IDLE;

        switch (ep0state) {

        case EP0_IDLE:
                udccsr0 = readl(UDCCSR0);
                /* Start control request? */
                if ((udccsr0 & (UDCCSR0_OPC | UDCCSR0_SA | UDCCSR0_RNE))
                        == (UDCCSR0_OPC | UDCCSR0_SA | UDCCSR0_RNE)) {

                        /* Read SETUP packet.
                         * SETUP packet size is 8 bytes (aka 2 words)
                         */
                        usbdbg("try reading SETUP packet");
                        for (i = 0; i < 2; i++) {
                                if ((readl(UDCCSR0) & UDCCSR0_RNE) == 0) {
                                        usberr("setup packet too short:%d", i);
                                        goto stall;
                                }
                                data[i] = readl(UDCDR0);
                        }

                        writel(readl(UDCCSR0) | UDCCSR0_OPC | UDCCSR0_SA, UDCCSR0);
                        if ((readl(UDCCSR0) & UDCCSR0_RNE) != 0) {
                                usberr("setup packet too long");
                                goto stall;
                        }

                        udc_dump_buffer("ep0 setup read", (u8 *) data, 8);

                        if (ep0_urb->device_request.wLength == 0) {
                                usbdbg("Zero Data control Packet\n");
                                if (ep0_recv_setup(ep0_urb)) {
                                        usberr("Invalid Setup Packet\n");
                                        udc_dump_buffer("ep0 setup read",
                                                                (u8 *)data, 8);
                                        goto stall;
                                }
                                writel(UDCCSR0_IPR, UDCCSR0);
                                ep0state = EP0_IDLE;
                        } else {
                                /* Check direction */
                                if ((ep0_urb->device_request.bmRequestType &
                                                USB_REQ_DIRECTION_MASK)
                                                == USB_REQ_HOST2DEVICE) {
                                        ep0state = EP0_OUT_DATA;
                                        ep0_urb->buffer =
                                                (u8 *)ep0_urb->buffer_data;
                                        ep0_urb->buffer_length =
                                                sizeof(ep0_urb->buffer_data);
                                        ep0_urb->actual_length = 0;
                                        writel(UDCCSR0_IPR, UDCCSR0);
                                } else {
                                        /* The ep0_recv_setup function has
                                         * already placed our response packet
                                         * data in ep0_urb->buffer and the
                                         * packet length in
                                         * ep0_urb->actual_length.
                                         */
                                        if (ep0_recv_setup(ep0_urb)) {
stall:
                                                usberr("Invalid setup packet");
                                                udc_dump_buffer("ep0 setup read"
                                                        , (u8 *) data, 8);
                                                ep0state = EP0_IDLE;

                                                writel(UDCCSR0_SA |
                                                UDCCSR0_OPC | UDCCSR0_FST |
                                                UDCCS0_FTF, UDCCSR0);

                                                return;
                                        }

                                        endpoint->tx_urb = ep0_urb;
                                        endpoint->sent = 0;
                                        usbdbg("EP0_IN_DATA");
                                        ep0state = EP0_IN_DATA;
                                        if (udc_write_urb(endpoint) < 0)
                                                goto stall;

                                }
                        }
                        return;
                } else if ((udccsr0 & (UDCCSR0_OPC | UDCCSR0_SA))
                        == (UDCCSR0_OPC|UDCCSR0_SA)) {
                        usberr("Setup Active but no data. Stalling ....\n");
                        goto stall;
                } else {
                        usbdbg("random early IRQs");
                        /* Some random early IRQs:
                         * - we acked FST
                         * - IPR cleared
                         * - OPC got set, without SA (likely status stage)
                         */
                        writel(udccsr0 & (UDCCSR0_SA | UDCCSR0_OPC), UDCCSR0);
                }
                break;

        case EP0_OUT_DATA:

                if ((udccsr0 & UDCCSR0_OPC) && !(udccsr0 & UDCCSR0_SA)) {
                        if (udc_read_urb_ep0()) {
read_complete:
                                ep0state = EP0_IDLE;
                                if (ep0_recv_setup(ep0_urb)) {
                                        /* Not a setup packet, stall next
                                         * EP0 transaction
                                         */
                                        udc_dump_buffer("ep0 setup read",
                                                        (u8 *) data, 8);
                                        usberr("can't parse setup packet\n");
                                        goto stall;
                                }
                        }
                } else if (!(udccsr0 & UDCCSR0_OPC) &&
                                !(udccsr0 & UDCCSR0_IPR)) {
                        if (ep0_urb->device_request.wLength ==
                                ep0_urb->actual_length)
                                goto read_complete;

                        usberr("Premature Status\n");
                        ep0state = EP0_IDLE;
                }
                break;

        case EP0_IN_DATA:
                /* GET_DESCRIPTOR etc */
                if (udccsr0 & UDCCSR0_OPC) {
                        writel(UDCCSR0_OPC | UDCCSR0_FTF, UDCCSR0);
                        usberr("ep0in premature status");
                        ep0state = EP0_IDLE;
                } else {
                        /* irq was IPR clearing */
                        if (udc_write_urb(endpoint) < 0) {
                                usberr("ep0_write_error\n");
                                goto stall;
                        }
                }
                break;

        case EP0_XFER_COMPLETE:
                writel(UDCCSR0_IPR, UDCCSR0);
                ep0state = EP0_IDLE;
                break;

        default:
                usbdbg("Default\n");
        }
        writel(USIR0_IR0, USIR0);
}

static void udc_handle_ep(struct usb_endpoint_instance *endpoint)
{
        int ep_addr = endpoint->endpoint_address;
        int ep_num = ep_addr & USB_ENDPOINT_NUMBER_MASK;
        int ep_isout = (ep_addr & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT;

        u32 flags = readl(UDCCSN(ep_num)) & (UDCCSR_SST | UDCCSR_TRN);
        if (flags)
                writel(flags, UDCCSN(ep_num));

        if (ep_isout)
                udc_read_urb(endpoint);
        else
                udc_write_urb(endpoint);

        writel(UDCCSR_PC, UDCCSN(ep_num));
}

static void udc_state_changed(void)
{

        writel(readl(UDCCR) | UDCCR_SMAC, UDCCR);

        usbdbg("New UDC settings are: conf %d - inter %d - alter %d",
               (readl(UDCCR) & UDCCR_ACN) >> UDCCR_ACN_S,
               (readl(UDCCR) & UDCCR_AIN) >> UDCCR_AIN_S,
               (readl(UDCCR) & UDCCR_AAISN) >> UDCCR_AAISN_S);

        usbd_device_event_irq(udc_device, DEVICE_CONFIGURED, 0);
        writel(UDCISR1_IRCC, UDCISR1);
}

void udc_irq(void)
{
        int handled;
        struct usb_endpoint_instance *endpoint;
        int ep_num, i;
        u32 udcisr0;

        do {
                handled = 0;
                /* Suspend Interrupt Request */
                if (readl(USIR1) & UDCCR_SUSIR) {
                        usbdbg("Suspend\n");
                        udc_ack_int_UDCCR(UDCCR_SUSIR);
                        handled = 1;
                        ep0state = EP0_IDLE;
                }

                /* Resume Interrupt Request */
                if (readl(USIR1) & UDCCR_RESIR) {
                        udc_ack_int_UDCCR(UDCCR_RESIR);
                        handled = 1;
                        usbdbg("USB resume\n");
                }

                if (readl(USIR1) & (1<<31)) {
                        handled = 1;
                        udc_state_changed();
                }

                /* Reset Interrupt Request */
                if (readl(USIR1) & UDCCR_RSTIR) {
                        udc_ack_int_UDCCR(UDCCR_RSTIR);
                        handled = 1;
                        usbdbg("Reset\n");
                        usbd_device_event_irq(udc_device, DEVICE_RESET, 0);
                } else {
                        if (readl(USIR0))
                                usbdbg("UISR0: %x \n", readl(USIR0));

                        if (readl(USIR0) & 0x2)
                                writel(0x2, USIR0);

                        /* Control traffic */
                        if (readl(USIR0)  & USIR0_IR0) {
                                handled = 1;
                                writel(USIR0_IR0, USIR0);
                                udc_handle_ep0(udc_device->bus->endpoint_array);
                        }

                        endpoint = udc_device->bus->endpoint_array;
                        for (i = 0; i < udc_device->bus->max_endpoints; i++) {
                                ep_num = (endpoint[i].endpoint_address) &
                                                USB_ENDPOINT_NUMBER_MASK;
                                if (!ep_num)
                                        continue;
                                udcisr0 = readl(UDCISR0);
                                if (udcisr0 &
                                        UDCISR_INT(ep_num, UDC_INT_PACKETCMP)) {
                                        writel(UDCISR_INT(ep_num, UDC_INT_PACKETCMP),
                                               UDCISR0);
                                        udc_handle_ep(&endpoint[i]);
                                }
                        }
                }

        } while (handled);
}

/* The UDCCR reg contains mask and interrupt status bits,
 * so using '|=' isn't safe as it may ack an interrupt.
 */
#define UDCCR_OEN               (1 << 31)   /* On-the-Go Enable */
#define UDCCR_MASK_BITS         (UDCCR_OEN | UDCCR_UDE)

static inline void udc_set_mask_UDCCR(int mask)
{
    writel((readl(UDCCR) & UDCCR_MASK_BITS) | (mask & UDCCR_MASK_BITS), UDCCR);
}

static inline void udc_clear_mask_UDCCR(int mask)
{
    writel((readl(UDCCR) & UDCCR_MASK_BITS) & ~(mask & UDCCR_MASK_BITS), UDCCR);
}

static void pio_irq_enable(int ep_num)
{
        if (ep_num < 16)
                writel(readl(UDCICR0) | 3 << (ep_num * 2), UDCICR0);
        else {
                ep_num -= 16;
                writel(readl(UDCICR1) | 3 << (ep_num * 2), UDCICR1);
        }
}

/*
 * udc_set_nak
 *
 * Allow upper layers to signal lower layers should not accept more RX data
 */
void udc_set_nak(int ep_num)
{
        /* TODO */
}

/*
 * udc_unset_nak
 *
 * Suspend sending of NAK tokens for DATA OUT tokens on a given endpoint.
 * Switch off NAKing on this endpoint to accept more data output from host.
 */
void udc_unset_nak(int ep_num)
{
        /* TODO */
}

int udc_endpoint_write(struct usb_endpoint_instance *endpoint)
{
        return udc_write_urb(endpoint);
}

/* Associate a physical endpoint with endpoint instance */
void udc_setup_ep(struct usb_device_instance *device, unsigned int id,
                                struct usb_endpoint_instance *endpoint)
{
        int ep_num, ep_addr, ep_isout, ep_type, ep_size;
        int config, interface, alternate;
        u32 tmp;

        usbdbg("setting up endpoint id %d", id);

        if (!endpoint) {
                usberr("endpoint void!");
                return;
        }

        ep_num = endpoint->endpoint_address & USB_ENDPOINT_NUMBER_MASK;
        if (ep_num >= UDC_MAX_ENDPOINTS) {
                usberr("unable to setup ep %d!", ep_num);
                return;
        }

        pio_irq_enable(ep_num);
        if (ep_num == 0) {
                /* Done for ep0 */
                return;
        }

        config = 1;
        interface = 0;
        alternate = 0;

        usbdbg("config %d - interface %d - alternate %d",
                config, interface, alternate);

        ep_addr = endpoint->endpoint_address;
        ep_num = ep_addr & USB_ENDPOINT_NUMBER_MASK;
        ep_isout = (ep_addr & USB_ENDPOINT_DIR_MASK) == USB_DIR_OUT;
        ep_type = ep_isout ? endpoint->rcv_attributes : endpoint->tx_attributes;
        ep_size = ep_isout ? endpoint->rcv_packetSize : endpoint->tx_packetSize;

        usbdbg("addr %x, num %d, dir %s, type %s, packet size %d",
                ep_addr, ep_num,
                ep_isout ? "out" : "in",
                ep_type == USB_ENDPOINT_XFER_ISOC ? "isoc" :
                ep_type == USB_ENDPOINT_XFER_BULK ? "bulk" :
                ep_type == USB_ENDPOINT_XFER_INT ? "int" : "???",
                ep_size
                );

        /* Configure UDCCRx */
        tmp = 0;
        tmp |= (config << UDCCONR_CN_S) & UDCCONR_CN;
        tmp |= (interface << UDCCONR_IN_S) & UDCCONR_IN;
        tmp |= (alternate << UDCCONR_AISN_S) & UDCCONR_AISN;
        tmp |= (ep_num << UDCCONR_EN_S) & UDCCONR_EN;
        tmp |= (ep_type << UDCCONR_ET_S) & UDCCONR_ET;
        tmp |= ep_isout ? 0 : UDCCONR_ED;
        tmp |= (ep_size << UDCCONR_MPS_S) & UDCCONR_MPS;
        tmp |= UDCCONR_EE;

        writel(tmp, UDCCN(ep_num));

        usbdbg("UDCCR%c = %x", 'A' + ep_num-1, readl(UDCCN(ep_num)));
        usbdbg("UDCCSR%c = %x", 'A' + ep_num-1, readl(UDCCSN(ep_num)));
}

/* Connect the USB device to the bus */
void udc_connect(void)
{
        usbdbg("UDC connect");

#ifdef CONFIG_USB_DEV_PULLUP_GPIO
        /* Turn on the USB connection by enabling the pullup resistor */
        writel(readl(GPDR(CONFIG_USB_DEV_PULLUP_GPIO))
                     | GPIO_bit(CONFIG_USB_DEV_PULLUP_GPIO),
               GPDR(CONFIG_USB_DEV_PULLUP_GPIO));
        writel(GPIO_bit(CONFIG_USB_DEV_PULLUP_GPIO), GPSR(CONFIG_USB_DEV_PULLUP_GPIO));
#else
        /* Host port 2 transceiver D+ pull up enable */
        writel(readl(UP2OCR) | UP2OCR_DPPUE, UP2OCR);
#endif
}

/* Disconnect the USB device to the bus */
void udc_disconnect(void)
{
        usbdbg("UDC disconnect");

#ifdef CONFIG_USB_DEV_PULLUP_GPIO
        /* Turn off the USB connection by disabling the pullup resistor */
        writel(GPIO_bit(CONFIG_USB_DEV_PULLUP_GPIO), GPCR(CONFIG_USB_DEV_PULLUP_GPIO));
#else
        /* Host port 2 transceiver D+ pull up disable */
        writel(readl(UP2OCR) & ~UP2OCR_DPPUE, UP2OCR);
#endif
}

/* Switch on the UDC */
void udc_enable(struct usb_device_instance *device)
{

        ep0state = EP0_IDLE;

        /* enable endpoint 0, A, B's Packet Complete Interrupt. */
        writel(0xffffffff, UDCICR0);
        writel(0xa8000000, UDCICR1);

        /* clear the interrupt status/control registers */
        writel(0xffffffff, UDCISR0);
        writel(0xffffffff, UDCISR1);

        /* set UDC-enable */
        udc_set_mask_UDCCR(UDCCR_UDE);

        udc_device = device;
        if (!ep0_urb)
                ep0_urb = usbd_alloc_urb(udc_device,
                                udc_device->bus->endpoint_array);
        else
                usbinfo("ep0_urb %p already allocated", ep0_urb);

        usbdbg("UDC Enabled\n");
}

/* Need to check this again */
void udc_disable(void)
{
        usbdbg("disable UDC");

        udc_clear_mask_UDCCR(UDCCR_UDE);

        /* Disable clock for USB device */
        writel(readl(CKEN) & ~CKEN11_USB, CKEN);

        /* Free ep0 URB */
        if (ep0_urb) {
                usbd_dealloc_urb(ep0_urb);
                ep0_urb = NULL;
        }

        /* Reset device pointer */
        udc_device = NULL;
}

/* Allow udc code to do any additional startup */
void udc_startup_events(struct usb_device_instance *device)
{
        /* The DEVICE_INIT event puts the USB device in the state STATE_INIT */
        usbd_device_event_irq(device, DEVICE_INIT, 0);

        /* The DEVICE_CREATE event puts the USB device in the state
         * STATE_ATTACHED */
        usbd_device_event_irq(device, DEVICE_CREATE, 0);

        /* Some USB controller driver implementations signal
         * DEVICE_HUB_CONFIGURED and DEVICE_RESET events here.
         * DEVICE_HUB_CONFIGURED causes a transition to the state
         * STATE_POWERED, and DEVICE_RESET causes a transition to
         * the state STATE_DEFAULT.
         */
        udc_enable(device);
}

/* Initialize h/w stuff */
int udc_init(void)
{
        udc_device = NULL;
        usbdbg("PXA27x usbd start");

        /* Enable clock for USB device */
        writel(readl(CKEN) | CKEN11_USB, CKEN);

        /* Disable the UDC */
        udc_clear_mask_UDCCR(UDCCR_UDE);

        /* Disable IRQs: we don't use them */
        writel(0, UDCICR0);
        writel(0, UDCICR1);

        return 0;
}