net: designware: Respect "bus mode" register contents on SW reset

[people/ms/u-boot.git] / common / usb.c

/*
 * Most of this source has been derived from the Linux USB
 * project:
 * (C) Copyright Linus Torvalds 1999
 * (C) Copyright Johannes Erdfelt 1999-2001
 * (C) Copyright Andreas Gal 1999
 * (C) Copyright Gregory P. Smith 1999
 * (C) Copyright Deti Fliegl 1999 (new USB architecture)
 * (C) Copyright Randy Dunlap 2000
 * (C) Copyright David Brownell 2000 (kernel hotplug, usb_device_id)
 * (C) Copyright Yggdrasil Computing, Inc. 2000
 *     (usb_device_id matching changes by Adam J. Richter)
 *
 * Adapted for U-Boot:
 * (C) Copyright 2001 Denis Peter, MPL AG Switzerland
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

/*
 * How it works:
 *
 * Since this is a bootloader, the devices will not be automatic
 * (re)configured on hotplug, but after a restart of the USB the
 * device should work.
 *
 * For each transfer (except "Interrupt") we wait for completion.
 */
#include <common.h>
#include <command.h>
#include <asm/processor.h>
#include <linux/compiler.h>
#include <linux/ctype.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
#include <compiler.h>

#include <usb.h>
#ifdef CONFIG_4xx
#include <asm/4xx_pci.h>
#endif

#define USB_BUFSIZ      512

static struct usb_device usb_dev[USB_MAX_DEVICE];
static int dev_index;
static int asynch_allowed;

char usb_started; /* flag for the started/stopped USB status */

#ifndef CONFIG_USB_MAX_CONTROLLER_COUNT
#define CONFIG_USB_MAX_CONTROLLER_COUNT 1
#endif

/***************************************************************************
 * Init USB Device
 */
int usb_init(void)
{
        void *ctrl;
        struct usb_device *dev;
        int i, start_index = 0;

        dev_index = 0;
        asynch_allowed = 1;
        usb_hub_reset();

        /* first make all devices unknown */
        for (i = 0; i < USB_MAX_DEVICE; i++) {
                memset(&usb_dev[i], 0, sizeof(struct usb_device));
                usb_dev[i].devnum = -1;
        }

        /* init low_level USB */
        for (i = 0; i < CONFIG_USB_MAX_CONTROLLER_COUNT; i++) {
                /* init low_level USB */
                printf("USB%d:   ", i);
                if (usb_lowlevel_init(i, USB_INIT_HOST, &ctrl)) {
                        puts("lowlevel init failed\n");
                        continue;
                }
                /*
                 * lowlevel init is OK, now scan the bus for devices
                 * i.e. search HUBs and configure them
                 */
                start_index = dev_index;
                printf("scanning bus %d for devices... ", i);
                dev = usb_alloc_new_device(ctrl);
                /*
                 * device 0 is always present
                 * (root hub, so let it analyze)
                 */
                if (dev)
                        usb_new_device(dev);

                if (start_index == dev_index)
                        puts("No USB Device found\n");
                else
                        printf("%d USB Device(s) found\n",
                                dev_index - start_index);

                usb_started = 1;
        }

        debug("scan end\n");
        /* if we were not able to find at least one working bus, bail out */
        if (!usb_started) {
                puts("USB error: all controllers failed lowlevel init\n");
                return -1;
        }

        return 0;
}

/******************************************************************************
 * Stop USB this stops the LowLevel Part and deregisters USB devices.
 */
int usb_stop(void)
{
        int i;

        if (usb_started) {
                asynch_allowed = 1;
                usb_started = 0;
                usb_hub_reset();

                for (i = 0; i < CONFIG_USB_MAX_CONTROLLER_COUNT; i++) {
                        if (usb_lowlevel_stop(i))
                                printf("failed to stop USB controller %d\n", i);
                }
        }

        return 0;
}

/*
 * disables the asynch behaviour of the control message. This is used for data
 * transfers that uses the exclusiv access to the control and bulk messages.
 * Returns the old value so it can be restored later.
 */
int usb_disable_asynch(int disable)
{
        int old_value = asynch_allowed;

        asynch_allowed = !disable;
        return old_value;
}


/*-------------------------------------------------------------------
 * Message wrappers.
 *
 */

/*
 * submits an Interrupt Message
 */
int usb_submit_int_msg(struct usb_device *dev, unsigned long pipe,
                        void *buffer, int transfer_len, int interval)
{
        return submit_int_msg(dev, pipe, buffer, transfer_len, interval);
}

/*
 * submits a control message and waits for comletion (at least timeout * 1ms)
 * If timeout is 0, we don't wait for completion (used as example to set and
 * clear keyboards LEDs). For data transfers, (storage transfers) we don't
 * allow control messages with 0 timeout, by previousely resetting the flag
 * asynch_allowed (usb_disable_asynch(1)).
 * returns the transfered length if OK or -1 if error. The transfered length
 * and the current status are stored in the dev->act_len and dev->status.
 */
int usb_control_msg(struct usb_device *dev, unsigned int pipe,
                        unsigned char request, unsigned char requesttype,
                        unsigned short value, unsigned short index,
                        void *data, unsigned short size, int timeout)
{
        ALLOC_CACHE_ALIGN_BUFFER(struct devrequest, setup_packet, 1);

        if ((timeout == 0) && (!asynch_allowed)) {
                /* request for a asynch control pipe is not allowed */
                return -1;
        }

        /* set setup command */
        setup_packet->requesttype = requesttype;
        setup_packet->request = request;
        setup_packet->value = cpu_to_le16(value);
        setup_packet->index = cpu_to_le16(index);
        setup_packet->length = cpu_to_le16(size);
        debug("usb_control_msg: request: 0x%X, requesttype: 0x%X, " \
              "value 0x%X index 0x%X length 0x%X\n",
              request, requesttype, value, index, size);
        dev->status = USB_ST_NOT_PROC; /*not yet processed */

        if (submit_control_msg(dev, pipe, data, size, setup_packet) < 0)
                return -1;
        if (timeout == 0)
                return (int)size;

        /*
         * Wait for status to update until timeout expires, USB driver
         * interrupt handler may set the status when the USB operation has
         * been completed.
         */
        while (timeout--) {
                if (!((volatile unsigned long)dev->status & USB_ST_NOT_PROC))
                        break;
                mdelay(1);
        }
        if (dev->status)
                return -1;

        return dev->act_len;

}

/*-------------------------------------------------------------------
 * submits bulk message, and waits for completion. returns 0 if Ok or
 * -1 if Error.
 * synchronous behavior
 */
int usb_bulk_msg(struct usb_device *dev, unsigned int pipe,
                        void *data, int len, int *actual_length, int timeout)
{
        if (len < 0)
                return -1;
        dev->status = USB_ST_NOT_PROC; /*not yet processed */
        if (submit_bulk_msg(dev, pipe, data, len) < 0)
                return -1;
        while (timeout--) {
                if (!((volatile unsigned long)dev->status & USB_ST_NOT_PROC))
                        break;
                mdelay(1);
        }
        *actual_length = dev->act_len;
        if (dev->status == 0)
                return 0;
        else
                return -1;
}


/*-------------------------------------------------------------------
 * Max Packet stuff
 */

/*
 * returns the max packet size, depending on the pipe direction and
 * the configurations values
 */
int usb_maxpacket(struct usb_device *dev, unsigned long pipe)
{
        /* direction is out -> use emaxpacket out */
        if ((pipe & USB_DIR_IN) == 0)
                return dev->epmaxpacketout[((pipe>>15) & 0xf)];
        else
                return dev->epmaxpacketin[((pipe>>15) & 0xf)];
}

/*
 * The routine usb_set_maxpacket_ep() is extracted from the loop of routine
 * usb_set_maxpacket(), because the optimizer of GCC 4.x chokes on this routine
 * when it is inlined in 1 single routine. What happens is that the register r3
 * is used as loop-count 'i', but gets overwritten later on.
 * This is clearly a compiler bug, but it is easier to workaround it here than
 * to update the compiler (Occurs with at least several GCC 4.{1,2},x
 * CodeSourcery compilers like e.g. 2007q3, 2008q1, 2008q3 lite editions on ARM)
 *
 * NOTE: Similar behaviour was observed with GCC4.6 on ARMv5.
 */
static void noinline
usb_set_maxpacket_ep(struct usb_device *dev, int if_idx, int ep_idx)
{
        int b;
        struct usb_endpoint_descriptor *ep;
        u16 ep_wMaxPacketSize;

        ep = &dev->config.if_desc[if_idx].ep_desc[ep_idx];

        b = ep->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
        ep_wMaxPacketSize = get_unaligned(&ep->wMaxPacketSize);

        if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
                                                USB_ENDPOINT_XFER_CONTROL) {
                /* Control => bidirectional */
                dev->epmaxpacketout[b] = ep_wMaxPacketSize;
                dev->epmaxpacketin[b] = ep_wMaxPacketSize;
                debug("##Control EP epmaxpacketout/in[%d] = %d\n",
                      b, dev->epmaxpacketin[b]);
        } else {
                if ((ep->bEndpointAddress & 0x80) == 0) {
                        /* OUT Endpoint */
                        if (ep_wMaxPacketSize > dev->epmaxpacketout[b]) {
                                dev->epmaxpacketout[b] = ep_wMaxPacketSize;
                                debug("##EP epmaxpacketout[%d] = %d\n",
                                      b, dev->epmaxpacketout[b]);
                        }
                } else {
                        /* IN Endpoint */
                        if (ep_wMaxPacketSize > dev->epmaxpacketin[b]) {
                                dev->epmaxpacketin[b] = ep_wMaxPacketSize;
                                debug("##EP epmaxpacketin[%d] = %d\n",
                                      b, dev->epmaxpacketin[b]);
                        }
                } /* if out */
        } /* if control */
}

/*
 * set the max packed value of all endpoints in the given configuration
 */
static int usb_set_maxpacket(struct usb_device *dev)
{
        int i, ii;

        for (i = 0; i < dev->config.desc.bNumInterfaces; i++)
                for (ii = 0; ii < dev->config.if_desc[i].desc.bNumEndpoints; ii++)
                        usb_set_maxpacket_ep(dev, i, ii);

        return 0;
}

/*******************************************************************************
 * Parse the config, located in buffer, and fills the dev->config structure.
 * Note that all little/big endian swapping are done automatically.
 * (wTotalLength has already been swapped and sanitized when it was read.)
 */
static int usb_parse_config(struct usb_device *dev,
                        unsigned char *buffer, int cfgno)
{
        struct usb_descriptor_header *head;
        int index, ifno, epno, curr_if_num;
        u16 ep_wMaxPacketSize;
        struct usb_interface *if_desc = NULL;

        ifno = -1;
        epno = -1;
        curr_if_num = -1;

        dev->configno = cfgno;
        head = (struct usb_descriptor_header *) &buffer[0];
        if (head->bDescriptorType != USB_DT_CONFIG) {
                printf(" ERROR: NOT USB_CONFIG_DESC %x\n",
                        head->bDescriptorType);
                return -1;
        }
        if (head->bLength != USB_DT_CONFIG_SIZE) {
                printf("ERROR: Invalid USB CFG length (%d)\n", head->bLength);
                return -1;
        }
        memcpy(&dev->config, head, USB_DT_CONFIG_SIZE);
        dev->config.no_of_if = 0;

        index = dev->config.desc.bLength;
        /* Ok the first entry must be a configuration entry,
         * now process the others */
        head = (struct usb_descriptor_header *) &buffer[index];
        while (index + 1 < dev->config.desc.wTotalLength && head->bLength) {
                switch (head->bDescriptorType) {
                case USB_DT_INTERFACE:
                        if (head->bLength != USB_DT_INTERFACE_SIZE) {
                                printf("ERROR: Invalid USB IF length (%d)\n",
                                        head->bLength);
                                break;
                        }
                        if (index + USB_DT_INTERFACE_SIZE >
                            dev->config.desc.wTotalLength) {
                                puts("USB IF descriptor overflowed buffer!\n");
                                break;
                        }
                        if (((struct usb_interface_descriptor *) \
                             head)->bInterfaceNumber != curr_if_num) {
                                /* this is a new interface, copy new desc */
                                ifno = dev->config.no_of_if;
                                if (ifno >= USB_MAXINTERFACES) {
                                        puts("Too many USB interfaces!\n");
                                        /* try to go on with what we have */
                                        return 1;
                                }
                                if_desc = &dev->config.if_desc[ifno];
                                dev->config.no_of_if++;
                                memcpy(if_desc, head,
                                        USB_DT_INTERFACE_SIZE);
                                if_desc->no_of_ep = 0;
                                if_desc->num_altsetting = 1;
                                curr_if_num =
                                     if_desc->desc.bInterfaceNumber;
                        } else {
                                /* found alternate setting for the interface */
                                if (ifno >= 0) {
                                        if_desc = &dev->config.if_desc[ifno];
                                        if_desc->num_altsetting++;
                                }
                        }
                        break;
                case USB_DT_ENDPOINT:
                        if (head->bLength != USB_DT_ENDPOINT_SIZE) {
                                printf("ERROR: Invalid USB EP length (%d)\n",
                                        head->bLength);
                                break;
                        }
                        if (index + USB_DT_ENDPOINT_SIZE >
                            dev->config.desc.wTotalLength) {
                                puts("USB EP descriptor overflowed buffer!\n");
                                break;
                        }
                        if (ifno < 0) {
                                puts("Endpoint descriptor out of order!\n");
                                break;
                        }
                        epno = dev->config.if_desc[ifno].no_of_ep;
                        if_desc = &dev->config.if_desc[ifno];
                        if (epno > USB_MAXENDPOINTS) {
                                printf("Interface %d has too many endpoints!\n",
                                        if_desc->desc.bInterfaceNumber);
                                return 1;
                        }
                        /* found an endpoint */
                        if_desc->no_of_ep++;
                        memcpy(&if_desc->ep_desc[epno], head,
                                USB_DT_ENDPOINT_SIZE);
                        ep_wMaxPacketSize = get_unaligned(&dev->config.\
                                                        if_desc[ifno].\
                                                        ep_desc[epno].\
                                                        wMaxPacketSize);
                        put_unaligned(le16_to_cpu(ep_wMaxPacketSize),
                                        &dev->config.\
                                        if_desc[ifno].\
                                        ep_desc[epno].\
                                        wMaxPacketSize);
                        debug("if %d, ep %d\n", ifno, epno);
                        break;
                case USB_DT_SS_ENDPOINT_COMP:
                        if (head->bLength != USB_DT_SS_EP_COMP_SIZE) {
                                printf("ERROR: Invalid USB EPC length (%d)\n",
                                        head->bLength);
                                break;
                        }
                        if (index + USB_DT_SS_EP_COMP_SIZE >
                            dev->config.desc.wTotalLength) {
                                puts("USB EPC descriptor overflowed buffer!\n");
                                break;
                        }
                        if (ifno < 0 || epno < 0) {
                                puts("EPC descriptor out of order!\n");
                                break;
                        }
                        if_desc = &dev->config.if_desc[ifno];
                        memcpy(&if_desc->ss_ep_comp_desc[epno], head,
                                USB_DT_SS_EP_COMP_SIZE);
                        break;
                default:
                        if (head->bLength == 0)
                                return 1;

                        debug("unknown Description Type : %x\n",
                              head->bDescriptorType);

#ifdef DEBUG
                        {
                                unsigned char *ch = (unsigned char *)head;
                                int i;

                                for (i = 0; i < head->bLength; i++)
                                        debug("%02X ", *ch++);
                                debug("\n\n\n");
                        }
#endif
                        break;
                }
                index += head->bLength;
                head = (struct usb_descriptor_header *)&buffer[index];
        }
        return 1;
}

/***********************************************************************
 * Clears an endpoint
 * endp: endpoint number in bits 0-3;
 * direction flag in bit 7 (1 = IN, 0 = OUT)
 */
int usb_clear_halt(struct usb_device *dev, int pipe)
{
        int result;
        int endp = usb_pipeendpoint(pipe)|(usb_pipein(pipe)<<7);

        result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                                 USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT, 0,
                                 endp, NULL, 0, USB_CNTL_TIMEOUT * 3);

        /* don't clear if failed */
        if (result < 0)
                return result;

        /*
         * NOTE: we do not get status and verify reset was successful
         * as some devices are reported to lock up upon this check..
         */

        usb_endpoint_running(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe));

        /* toggle is reset on clear */
        usb_settoggle(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe), 0);
        return 0;
}


/**********************************************************************
 * get_descriptor type
 */
static int usb_get_descriptor(struct usb_device *dev, unsigned char type,
                        unsigned char index, void *buf, int size)
{
        int res;
        res = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
                        USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
                        (type << 8) + index, 0,
                        buf, size, USB_CNTL_TIMEOUT);
        return res;
}

/**********************************************************************
 * gets configuration cfgno and store it in the buffer
 */
int usb_get_configuration_no(struct usb_device *dev,
                             unsigned char *buffer, int cfgno)
{
        int result;
        unsigned int length;
        struct usb_config_descriptor *config;

        config = (struct usb_config_descriptor *)&buffer[0];
        result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno, buffer, 9);
        if (result < 9) {
                if (result < 0)
                        printf("unable to get descriptor, error %lX\n",
                                dev->status);
                else
                        printf("config descriptor too short " \
                                "(expected %i, got %i)\n", 9, result);
                return -1;
        }
        length = le16_to_cpu(config->wTotalLength);

        if (length > USB_BUFSIZ) {
                printf("%s: failed to get descriptor - too long: %d\n",
                        __func__, length);
                return -1;
        }

        result = usb_get_descriptor(dev, USB_DT_CONFIG, cfgno, buffer, length);
        debug("get_conf_no %d Result %d, wLength %d\n", cfgno, result, length);
        config->wTotalLength = length; /* validated, with CPU byte order */

        return result;
}

/********************************************************************
 * set address of a device to the value in dev->devnum.
 * This can only be done by addressing the device via the default address (0)
 */
static int usb_set_address(struct usb_device *dev)
{
        int res;

        debug("set address %d\n", dev->devnum);
        res = usb_control_msg(dev, usb_snddefctrl(dev),
                                USB_REQ_SET_ADDRESS, 0,
                                (dev->devnum), 0,
                                NULL, 0, USB_CNTL_TIMEOUT);
        return res;
}

/********************************************************************
 * set interface number to interface
 */
int usb_set_interface(struct usb_device *dev, int interface, int alternate)
{
        struct usb_interface *if_face = NULL;
        int ret, i;

        for (i = 0; i < dev->config.desc.bNumInterfaces; i++) {
                if (dev->config.if_desc[i].desc.bInterfaceNumber == interface) {
                        if_face = &dev->config.if_desc[i];
                        break;
                }
        }
        if (!if_face) {
                printf("selecting invalid interface %d", interface);
                return -1;
        }
        /*
         * We should return now for devices with only one alternate setting.
         * According to 9.4.10 of the Universal Serial Bus Specification
         * Revision 2.0 such devices can return with a STALL. This results in
         * some USB sticks timeouting during initialization and then being
         * unusable in U-Boot.
         */
        if (if_face->num_altsetting == 1)
                return 0;

        ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                                USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE,
                                alternate, interface, NULL, 0,
                                USB_CNTL_TIMEOUT * 5);
        if (ret < 0)
                return ret;

        return 0;
}

/********************************************************************
 * set configuration number to configuration
 */
static int usb_set_configuration(struct usb_device *dev, int configuration)
{
        int res;
        debug("set configuration %d\n", configuration);
        /* set setup command */
        res = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                                USB_REQ_SET_CONFIGURATION, 0,
                                configuration, 0,
                                NULL, 0, USB_CNTL_TIMEOUT);
        if (res == 0) {
                dev->toggle[0] = 0;
                dev->toggle[1] = 0;
                return 0;
        } else
                return -1;
}

/********************************************************************
 * set protocol to protocol
 */
int usb_set_protocol(struct usb_device *dev, int ifnum, int protocol)
{
        return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                USB_REQ_SET_PROTOCOL, USB_TYPE_CLASS | USB_RECIP_INTERFACE,
                protocol, ifnum, NULL, 0, USB_CNTL_TIMEOUT);
}

/********************************************************************
 * set idle
 */
int usb_set_idle(struct usb_device *dev, int ifnum, int duration, int report_id)
{
        return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                USB_REQ_SET_IDLE, USB_TYPE_CLASS | USB_RECIP_INTERFACE,
                (duration << 8) | report_id, ifnum, NULL, 0, USB_CNTL_TIMEOUT);
}

/********************************************************************
 * get report
 */
int usb_get_report(struct usb_device *dev, int ifnum, unsigned char type,
                   unsigned char id, void *buf, int size)
{
        return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
                        USB_REQ_GET_REPORT,
                        USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
                        (type << 8) + id, ifnum, buf, size, USB_CNTL_TIMEOUT);
}

/********************************************************************
 * get class descriptor
 */
int usb_get_class_descriptor(struct usb_device *dev, int ifnum,
                unsigned char type, unsigned char id, void *buf, int size)
{
        return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
                USB_REQ_GET_DESCRIPTOR, USB_RECIP_INTERFACE | USB_DIR_IN,
                (type << 8) + id, ifnum, buf, size, USB_CNTL_TIMEOUT);
}

/********************************************************************
 * get string index in buffer
 */
static int usb_get_string(struct usb_device *dev, unsigned short langid,
                   unsigned char index, void *buf, int size)
{
        int i;
        int result;

        for (i = 0; i < 3; ++i) {
                /* some devices are flaky */
                result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
                        USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
                        (USB_DT_STRING << 8) + index, langid, buf, size,
                        USB_CNTL_TIMEOUT);

                if (result > 0)
                        break;
        }

        return result;
}


static void usb_try_string_workarounds(unsigned char *buf, int *length)
{
        int newlength, oldlength = *length;

        for (newlength = 2; newlength + 1 < oldlength; newlength += 2)
                if (!isprint(buf[newlength]) || buf[newlength + 1])
                        break;

        if (newlength > 2) {
                buf[0] = newlength;
                *length = newlength;
        }
}


static int usb_string_sub(struct usb_device *dev, unsigned int langid,
                unsigned int index, unsigned char *buf)
{
        int rc;

        /* Try to read the string descriptor by asking for the maximum
         * possible number of bytes */
        rc = usb_get_string(dev, langid, index, buf, 255);

        /* If that failed try to read the descriptor length, then
         * ask for just that many bytes */
        if (rc < 2) {
                rc = usb_get_string(dev, langid, index, buf, 2);
                if (rc == 2)
                        rc = usb_get_string(dev, langid, index, buf, buf[0]);
        }

        if (rc >= 2) {
                if (!buf[0] && !buf[1])
                        usb_try_string_workarounds(buf, &rc);

                /* There might be extra junk at the end of the descriptor */
                if (buf[0] < rc)
                        rc = buf[0];

                rc = rc - (rc & 1); /* force a multiple of two */
        }

        if (rc < 2)
                rc = -1;

        return rc;
}


/********************************************************************
 * usb_string:
 * Get string index and translate it to ascii.
 * returns string length (> 0) or error (< 0)
 */
int usb_string(struct usb_device *dev, int index, char *buf, size_t size)
{
        ALLOC_CACHE_ALIGN_BUFFER(unsigned char, mybuf, USB_BUFSIZ);
        unsigned char *tbuf;
        int err;
        unsigned int u, idx;

        if (size <= 0 || !buf || !index)
                return -1;
        buf[0] = 0;
        tbuf = &mybuf[0];

        /* get langid for strings if it's not yet known */
        if (!dev->have_langid) {
                err = usb_string_sub(dev, 0, 0, tbuf);
                if (err < 0) {
                        debug("error getting string descriptor 0 " \
                              "(error=%lx)\n", dev->status);
                        return -1;
                } else if (tbuf[0] < 4) {
                        debug("string descriptor 0 too short\n");
                        return -1;
                } else {
                        dev->have_langid = -1;
                        dev->string_langid = tbuf[2] | (tbuf[3] << 8);
                                /* always use the first langid listed */
                        debug("USB device number %d default " \
                              "language ID 0x%x\n",
                              dev->devnum, dev->string_langid);
                }
        }

        err = usb_string_sub(dev, dev->string_langid, index, tbuf);
        if (err < 0)
                return err;

        size--;         /* leave room for trailing NULL char in output buffer */
        for (idx = 0, u = 2; u < err; u += 2) {
                if (idx >= size)
                        break;
                if (tbuf[u+1])                  /* high byte */
                        buf[idx++] = '?';  /* non-ASCII character */
                else
                        buf[idx++] = tbuf[u];
        }
        buf[idx] = 0;
        err = idx;
        return err;
}


/********************************************************************
 * USB device handling:
 * the USB device are static allocated [USB_MAX_DEVICE].
 */


/* returns a pointer to the device with the index [index].
 * if the device is not assigned (dev->devnum==-1) returns NULL
 */
struct usb_device *usb_get_dev_index(int index)
{
        if (usb_dev[index].devnum == -1)
                return NULL;
        else
                return &usb_dev[index];
}

/* returns a pointer of a new device structure or NULL, if
 * no device struct is available
 */
struct usb_device *usb_alloc_new_device(void *controller)
{
        int i;
        debug("New Device %d\n", dev_index);
        if (dev_index == USB_MAX_DEVICE) {
                printf("ERROR, too many USB Devices, max=%d\n", USB_MAX_DEVICE);
                return NULL;
        }
        /* default Address is 0, real addresses start with 1 */
        usb_dev[dev_index].devnum = dev_index + 1;
        usb_dev[dev_index].maxchild = 0;
        for (i = 0; i < USB_MAXCHILDREN; i++)
                usb_dev[dev_index].children[i] = NULL;
        usb_dev[dev_index].parent = NULL;
        usb_dev[dev_index].controller = controller;
        dev_index++;
        return &usb_dev[dev_index - 1];
}

/*
 * Free the newly created device node.
 * Called in error cases where configuring a newly attached
 * device fails for some reason.
 */
void usb_free_device(void)
{
        dev_index--;
        debug("Freeing device node: %d\n", dev_index);
        memset(&usb_dev[dev_index], 0, sizeof(struct usb_device));
        usb_dev[dev_index].devnum = -1;
}

/*
 * XHCI issues Enable Slot command and thereafter
 * allocates device contexts. Provide a weak alias
 * function for the purpose, so that XHCI overrides it
 * and EHCI/OHCI just work out of the box.
 */
__weak int usb_alloc_device(struct usb_device *udev)
{
        return 0;
}
/*
 * By the time we get here, the device has gotten a new device ID
 * and is in the default state. We need to identify the thing and
 * get the ball rolling..
 *
 * Returns 0 for success, != 0 for error.
 */
int usb_new_device(struct usb_device *dev)
{
        int addr, err;
        int tmp;
        ALLOC_CACHE_ALIGN_BUFFER(unsigned char, tmpbuf, USB_BUFSIZ);

        /*
         * Allocate usb 3.0 device context.
         * USB 3.0 (xHCI) protocol tries to allocate device slot
         * and related data structures first. This call does that.
         * Refer to sec 4.3.2 in xHCI spec rev1.0
         */
        if (usb_alloc_device(dev)) {
                printf("Cannot allocate device context to get SLOT_ID\n");
                return -1;
        }

        /* We still haven't set the Address yet */
        addr = dev->devnum;
        dev->devnum = 0;

#ifdef CONFIG_LEGACY_USB_INIT_SEQ
        /* this is the old and known way of initializing devices, it is
         * different than what Windows and Linux are doing. Windows and Linux
         * both retrieve 64 bytes while reading the device descriptor
         * Several USB stick devices report ERR: CTL_TIMEOUT, caused by an
         * invalid header while reading 8 bytes as device descriptor. */
        dev->descriptor.bMaxPacketSize0 = 8;        /* Start off at 8 bytes  */
        dev->maxpacketsize = PACKET_SIZE_8;
        dev->epmaxpacketin[0] = 8;
        dev->epmaxpacketout[0] = 8;

        err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, tmpbuf, 8);
        if (err < 8) {
                printf("\n      USB device not responding, " \
                       "giving up (status=%lX)\n", dev->status);
                return 1;
        }
        memcpy(&dev->descriptor, tmpbuf, 8);
#else
        /* This is a Windows scheme of initialization sequence, with double
         * reset of the device (Linux uses the same sequence)
         * Some equipment is said to work only with such init sequence; this
         * patch is based on the work by Alan Stern:
         * http://sourceforge.net/mailarchive/forum.php?
         * thread_id=5729457&forum_id=5398
         */
        __maybe_unused struct usb_device_descriptor *desc;
        int port = -1;
        struct usb_device *parent = dev->parent;
        unsigned short portstatus;

        /* send 64-byte GET-DEVICE-DESCRIPTOR request.  Since the descriptor is
         * only 18 bytes long, this will terminate with a short packet.  But if
         * the maxpacket size is 8 or 16 the device may be waiting to transmit
         * some more, or keeps on retransmitting the 8 byte header. */

        desc = (struct usb_device_descriptor *)tmpbuf;
        dev->descriptor.bMaxPacketSize0 = 64;       /* Start off at 64 bytes  */
        /* Default to 64 byte max packet size */
        dev->maxpacketsize = PACKET_SIZE_64;
        dev->epmaxpacketin[0] = 64;
        dev->epmaxpacketout[0] = 64;

        /*
         * XHCI needs to issue a Address device command to setup
         * proper device context structures, before it can interact
         * with the device. So a get_descriptor will fail before any
         * of that is done for XHCI unlike EHCI.
         */
#ifndef CONFIG_USB_XHCI
        err = usb_get_descriptor(dev, USB_DT_DEVICE, 0, desc, 64);
        if (err < 0) {
                debug("usb_new_device: usb_get_descriptor() failed\n");
                return 1;
        }

        dev->descriptor.bMaxPacketSize0 = desc->bMaxPacketSize0;
        /*
         * Fetch the device class, driver can use this info
         * to differentiate between HUB and DEVICE.
         */
        dev->descriptor.bDeviceClass = desc->bDeviceClass;
#endif

        if (parent) {
                int j;

                /* find the port number we're at */
                for (j = 0; j < parent->maxchild; j++) {
                        if (parent->children[j] == dev) {
                                port = j;
                                break;
                        }
                }
                if (port < 0) {
                        printf("usb_new_device:cannot locate device's port.\n");
                        return 1;
                }

                /* reset the port for the second time */
                err = hub_port_reset(dev->parent, port, &portstatus);
                if (err < 0) {
                        printf("\n     Couldn't reset port %i\n", port);
                        return 1;
                }
        }
#endif

        dev->epmaxpacketin[0] = dev->descriptor.bMaxPacketSize0;
        dev->epmaxpacketout[0] = dev->descriptor.bMaxPacketSize0;
        switch (dev->descriptor.bMaxPacketSize0) {
        case 8:
                dev->maxpacketsize  = PACKET_SIZE_8;
                break;
        case 16:
                dev->maxpacketsize = PACKET_SIZE_16;
                break;
        case 32:
                dev->maxpacketsize = PACKET_SIZE_32;
                break;
        case 64:
                dev->maxpacketsize = PACKET_SIZE_64;
                break;
        }
        dev->devnum = addr;

        err = usb_set_address(dev); /* set address */

        if (err < 0) {
                printf("\n      USB device not accepting new address " \
                        "(error=%lX)\n", dev->status);
                return 1;
        }

        mdelay(10);     /* Let the SET_ADDRESS settle */

        tmp = sizeof(dev->descriptor);

        err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
                                 tmpbuf, sizeof(dev->descriptor));
        if (err < tmp) {
                if (err < 0)
                        printf("unable to get device descriptor (error=%d)\n",
                               err);
                else
                        printf("USB device descriptor short read " \
                                "(expected %i, got %i)\n", tmp, err);
                return 1;
        }
        memcpy(&dev->descriptor, tmpbuf, sizeof(dev->descriptor));
        /* correct le values */
        le16_to_cpus(&dev->descriptor.bcdUSB);
        le16_to_cpus(&dev->descriptor.idVendor);
        le16_to_cpus(&dev->descriptor.idProduct);
        le16_to_cpus(&dev->descriptor.bcdDevice);
        /* only support for one config for now */
        err = usb_get_configuration_no(dev, tmpbuf, 0);
        if (err < 0) {
                printf("usb_new_device: Cannot read configuration, " \
                       "skipping device %04x:%04x\n",
                       dev->descriptor.idVendor, dev->descriptor.idProduct);
                return -1;
        }
        usb_parse_config(dev, tmpbuf, 0);
        usb_set_maxpacket(dev);
        /* we set the default configuration here */
        if (usb_set_configuration(dev, dev->config.desc.bConfigurationValue)) {
                printf("failed to set default configuration " \
                        "len %d, status %lX\n", dev->act_len, dev->status);
                return -1;
        }
        debug("new device strings: Mfr=%d, Product=%d, SerialNumber=%d\n",
              dev->descriptor.iManufacturer, dev->descriptor.iProduct,
              dev->descriptor.iSerialNumber);
        memset(dev->mf, 0, sizeof(dev->mf));
        memset(dev->prod, 0, sizeof(dev->prod));
        memset(dev->serial, 0, sizeof(dev->serial));
        if (dev->descriptor.iManufacturer)
                usb_string(dev, dev->descriptor.iManufacturer,
                           dev->mf, sizeof(dev->mf));
        if (dev->descriptor.iProduct)
                usb_string(dev, dev->descriptor.iProduct,
                           dev->prod, sizeof(dev->prod));
        if (dev->descriptor.iSerialNumber)
                usb_string(dev, dev->descriptor.iSerialNumber,
                           dev->serial, sizeof(dev->serial));
        debug("Manufacturer %s\n", dev->mf);
        debug("Product      %s\n", dev->prod);
        debug("SerialNumber %s\n", dev->serial);
        /* now prode if the device is a hub */
        usb_hub_probe(dev, 0);
        return 0;
}

__weak
int board_usb_init(int index, enum usb_init_type init)
{
        return 0;
}
/* EOF */