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zero.c

/*
 * zero.c -- Gadget Zero, for USB development
 *
 * Copyright (C) 2003-2007 David Brownell
 * All rights reserved.
 *
 * 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
 */


/*
 * Gadget Zero only needs two bulk endpoints, and is an example of how you
 * can write a hardware-agnostic gadget driver running inside a USB device.
 *
 * Hardware details are visible (see CONFIG_USB_ZERO_* below) but don't
 * affect most of the driver.
 *
 * Use it with the Linux host/master side "usbtest" driver to get a basic
 * functional test of your device-side usb stack, or with "usb-skeleton".
 *
 * It supports two similar configurations.  One sinks whatever the usb host
 * writes, and in return sources zeroes.  The other loops whatever the host
 * writes back, so the host can read it.  Module options include:
 *
 *   buflen=N           default N=4096, buffer size used
 *   qlen=N       default N=32, how many buffers in the loopback queue
 *   loopdefault  default false, list loopback config first
 *
 * Many drivers will only have one configuration, letting them be much
 * simpler if they also don't support high speed operation (like this
 * driver does).
 *
 * Why is *this* driver using two configurations, rather than setting up
 * two interfaces with different functions?  To help verify that multiple
 * configuration infrastucture is working correctly; also, so that it can
 * work with low capability USB controllers without four bulk endpoints.
 */

/* #define VERBOSE_DEBUG */

#include <linux/kernel.h>
#include <linux/utsname.h>
#include <linux/device.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

#include "gadget_chips.h"


/*-------------------------------------------------------------------------*/

#define DRIVER_VERSION        "Lughnasadh, 2007"

static const char shortname [] = "zero";
static const char longname [] = "Gadget Zero";

static const char source_sink [] = "source and sink data";
static const char loopback [] = "loop input to output";

/*-------------------------------------------------------------------------*/

/*
 * driver assumes self-powered hardware, and
 * has no way for users to trigger remote wakeup.
 *
 * this version autoconfigures as much as possible,
 * which is reasonable for most "bulk-only" drivers.
 */
static const char *EP_IN_NAME;            /* source */
static const char *EP_OUT_NAME;           /* sink */

/*-------------------------------------------------------------------------*/

/* big enough to hold our biggest descriptor */
#define USB_BUFSIZ      256

struct zero_dev {
      spinlock_t        lock;
      struct usb_gadget *gadget;
      struct usb_request      *req;       /* for control responses */

      /* when configured, we have one of two configs:
       * - source data (in to host) and sink it (out from host)
       * - or loop it back (out from host back in to host)
       */
      u8                config;
      struct usb_ep           *in_ep, *out_ep;

      /* autoresume timer */
      struct timer_list resume;
};

#define DBG(d, fmt, args...) \
      dev_dbg(&(d)->gadget->dev , fmt , ## args)
#define VDBG(d, fmt, args...) \
      dev_vdbg(&(d)->gadget->dev , fmt , ## args)
#define ERROR(d, fmt, args...) \
      dev_err(&(d)->gadget->dev , fmt , ## args)
#define WARN(d, fmt, args...) \
      dev_warn(&(d)->gadget->dev , fmt , ## args)
#define INFO(d, fmt, args...) \
      dev_info(&(d)->gadget->dev , fmt , ## args)

/*-------------------------------------------------------------------------*/

static unsigned buflen = 4096;
static unsigned qlen = 32;
static unsigned pattern = 0;

module_param (buflen, uint, S_IRUGO);
module_param (qlen, uint, S_IRUGO);
module_param (pattern, uint, S_IRUGO|S_IWUSR);

/*
 * if it's nonzero, autoresume says how many seconds to wait
 * before trying to wake up the host after suspend.
 */
static unsigned autoresume = 0;
module_param (autoresume, uint, 0);

/*
 * Normally the "loopback" configuration is second (index 1) so
 * it's not the default.  Here's where to change that order, to
 * work better with hosts where config changes are problematic.
 * Or controllers (like superh) that only support one config.
 */
static int loopdefault = 0;

module_param (loopdefault, bool, S_IRUGO|S_IWUSR);

/*-------------------------------------------------------------------------*/

/* Thanks to NetChip Technologies for donating this product ID.
 *
 * DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
 * Instead:  allocate your own, using normal USB-IF procedures.
 */
#ifndef     CONFIG_USB_ZERO_HNPTEST
#define DRIVER_VENDOR_NUM     0x0525            /* NetChip */
#define DRIVER_PRODUCT_NUM    0xa4a0            /* Linux-USB "Gadget Zero" */
#else
#define DRIVER_VENDOR_NUM     0x1a0a            /* OTG test device IDs */
#define DRIVER_PRODUCT_NUM    0xbadd
#endif

/*-------------------------------------------------------------------------*/

/*
 * DESCRIPTORS ... most are static, but strings and (full)
 * configuration descriptors are built on demand.
 */

#define STRING_MANUFACTURER         25
#define STRING_PRODUCT              42
#define STRING_SERIAL               101
#define STRING_SOURCE_SINK          250
#define STRING_LOOPBACK             251

/*
 * This device advertises two configurations; these numbers work
 * on a pxa250 as well as more flexible hardware.
 */
#define     CONFIG_SOURCE_SINK      3
#define     CONFIG_LOOPBACK         2

static struct usb_device_descriptor
device_desc = {
      .bLength =        sizeof device_desc,
      .bDescriptorType =      USB_DT_DEVICE,

      .bcdUSB =         __constant_cpu_to_le16 (0x0200),
      .bDeviceClass =         USB_CLASS_VENDOR_SPEC,

      .idVendor =       __constant_cpu_to_le16 (DRIVER_VENDOR_NUM),
      .idProduct =            __constant_cpu_to_le16 (DRIVER_PRODUCT_NUM),
      .iManufacturer =  STRING_MANUFACTURER,
      .iProduct =       STRING_PRODUCT,
      .iSerialNumber =  STRING_SERIAL,
      .bNumConfigurations =   2,
};

static struct usb_config_descriptor
source_sink_config = {
      .bLength =        sizeof source_sink_config,
      .bDescriptorType =      USB_DT_CONFIG,

      /* compute wTotalLength on the fly */
      .bNumInterfaces = 1,
      .bConfigurationValue =  CONFIG_SOURCE_SINK,
      .iConfiguration = STRING_SOURCE_SINK,
      .bmAttributes =         USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
      .bMaxPower =            1,    /* self-powered */
};

static struct usb_config_descriptor
loopback_config = {
      .bLength =        sizeof loopback_config,
      .bDescriptorType =      USB_DT_CONFIG,

      /* compute wTotalLength on the fly */
      .bNumInterfaces = 1,
      .bConfigurationValue =  CONFIG_LOOPBACK,
      .iConfiguration = STRING_LOOPBACK,
      .bmAttributes =         USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
      .bMaxPower =            1,    /* self-powered */
};

static struct usb_otg_descriptor
otg_descriptor = {
      .bLength =        sizeof otg_descriptor,
      .bDescriptorType =      USB_DT_OTG,

      .bmAttributes =         USB_OTG_SRP,
};

/* one interface in each configuration */

static const struct usb_interface_descriptor
source_sink_intf = {
      .bLength =        sizeof source_sink_intf,
      .bDescriptorType =      USB_DT_INTERFACE,

      .bNumEndpoints =  2,
      .bInterfaceClass =      USB_CLASS_VENDOR_SPEC,
      .iInterface =           STRING_SOURCE_SINK,
};

static const struct usb_interface_descriptor
loopback_intf = {
      .bLength =        sizeof loopback_intf,
      .bDescriptorType =      USB_DT_INTERFACE,

      .bNumEndpoints =  2,
      .bInterfaceClass =      USB_CLASS_VENDOR_SPEC,
      .iInterface =           STRING_LOOPBACK,
};

/* two full speed bulk endpoints; their use is config-dependent */

static struct usb_endpoint_descriptor
fs_source_desc = {
      .bLength =        USB_DT_ENDPOINT_SIZE,
      .bDescriptorType =      USB_DT_ENDPOINT,

      .bEndpointAddress =     USB_DIR_IN,
      .bmAttributes =         USB_ENDPOINT_XFER_BULK,
};

static struct usb_endpoint_descriptor
fs_sink_desc = {
      .bLength =        USB_DT_ENDPOINT_SIZE,
      .bDescriptorType =      USB_DT_ENDPOINT,

      .bEndpointAddress =     USB_DIR_OUT,
      .bmAttributes =         USB_ENDPOINT_XFER_BULK,
};

static const struct usb_descriptor_header *fs_source_sink_function [] = {
      (struct usb_descriptor_header *) &otg_descriptor,
      (struct usb_descriptor_header *) &source_sink_intf,
      (struct usb_descriptor_header *) &fs_sink_desc,
      (struct usb_descriptor_header *) &fs_source_desc,
      NULL,
};

static const struct usb_descriptor_header *fs_loopback_function [] = {
      (struct usb_descriptor_header *) &otg_descriptor,
      (struct usb_descriptor_header *) &loopback_intf,
      (struct usb_descriptor_header *) &fs_sink_desc,
      (struct usb_descriptor_header *) &fs_source_desc,
      NULL,
};

/*
 * usb 2.0 devices need to expose both high speed and full speed
 * descriptors, unless they only run at full speed.
 *
 * that means alternate endpoint descriptors (bigger packets)
 * and a "device qualifier" ... plus more construction options
 * for the config descriptor.
 */

static struct usb_endpoint_descriptor
hs_source_desc = {
      .bLength =        USB_DT_ENDPOINT_SIZE,
      .bDescriptorType =      USB_DT_ENDPOINT,

      .bmAttributes =         USB_ENDPOINT_XFER_BULK,
      .wMaxPacketSize = __constant_cpu_to_le16 (512),
};

static struct usb_endpoint_descriptor
hs_sink_desc = {
      .bLength =        USB_DT_ENDPOINT_SIZE,
      .bDescriptorType =      USB_DT_ENDPOINT,

      .bmAttributes =         USB_ENDPOINT_XFER_BULK,
      .wMaxPacketSize = __constant_cpu_to_le16 (512),
};

static struct usb_qualifier_descriptor
dev_qualifier = {
      .bLength =        sizeof dev_qualifier,
      .bDescriptorType =      USB_DT_DEVICE_QUALIFIER,

      .bcdUSB =         __constant_cpu_to_le16 (0x0200),
      .bDeviceClass =         USB_CLASS_VENDOR_SPEC,

      .bNumConfigurations =   2,
};

static const struct usb_descriptor_header *hs_source_sink_function [] = {
      (struct usb_descriptor_header *) &otg_descriptor,
      (struct usb_descriptor_header *) &source_sink_intf,
      (struct usb_descriptor_header *) &hs_source_desc,
      (struct usb_descriptor_header *) &hs_sink_desc,
      NULL,
};

static const struct usb_descriptor_header *hs_loopback_function [] = {
      (struct usb_descriptor_header *) &otg_descriptor,
      (struct usb_descriptor_header *) &loopback_intf,
      (struct usb_descriptor_header *) &hs_source_desc,
      (struct usb_descriptor_header *) &hs_sink_desc,
      NULL,
};

/* maxpacket and other transfer characteristics vary by speed. */
static inline struct usb_endpoint_descriptor *
ep_desc(struct usb_gadget *g, struct usb_endpoint_descriptor *hs,
            struct usb_endpoint_descriptor *fs)
{
      if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
            return hs;
      return fs;
}

static char manufacturer[50];

/* default serial number takes at least two packets */
static char serial[] = "0123456789.0123456789.0123456789";


/* static strings, in UTF-8 */
static struct usb_string            strings [] = {
      { STRING_MANUFACTURER, manufacturer, },
      { STRING_PRODUCT, longname, },
      { STRING_SERIAL, serial, },
      { STRING_LOOPBACK, loopback, },
      { STRING_SOURCE_SINK, source_sink, },
      {  }              /* end of list */
};

static struct usb_gadget_strings    stringtab = {
      .language   = 0x0409,   /* en-us */
      .strings    = strings,
};

/*
 * config descriptors are also handcrafted.  these must agree with code
 * that sets configurations, and with code managing interfaces and their
 * altsettings.  other complexity may come from:
 *
 *  - high speed support, including "other speed config" rules
 *  - multiple configurations
 *  - interfaces with alternate settings
 *  - embedded class or vendor-specific descriptors
 *
 * this handles high speed, and has a second config that could as easily
 * have been an alternate interface setting (on most hardware).
 *
 * NOTE:  to demonstrate (and test) more USB capabilities, this driver
 * should include an altsetting to test interrupt transfers, including
 * high bandwidth modes at high speed.  (Maybe work like Intel's test
 * device?)
 */
static int
config_buf (struct usb_gadget *gadget,
            u8 *buf, u8 type, unsigned index)
{
      int                     is_source_sink;
      int                     len;
      const struct usb_descriptor_header **function;
      int                     hs = 0;

      /* two configurations will always be index 0 and index 1 */
      if (index > 1)
            return -EINVAL;
      is_source_sink = loopdefault ? (index == 1) : (index == 0);

      if (gadget_is_dualspeed(gadget)) {
            hs = (gadget->speed == USB_SPEED_HIGH);
            if (type == USB_DT_OTHER_SPEED_CONFIG)
                  hs = !hs;
      }
      if (hs)
            function = is_source_sink
                  ? hs_source_sink_function
                  : hs_loopback_function;
      else
            function = is_source_sink
                  ? fs_source_sink_function
                  : fs_loopback_function;

      /* for now, don't advertise srp-only devices */
      if (!gadget_is_otg(gadget))
            function++;

      len = usb_gadget_config_buf (is_source_sink
                              ? &source_sink_config
                              : &loopback_config,
                  buf, USB_BUFSIZ, function);
      if (len < 0)
            return len;
      ((struct usb_config_descriptor *) buf)->bDescriptorType = type;
      return len;
}

/*-------------------------------------------------------------------------*/

static struct usb_request *
alloc_ep_req (struct usb_ep *ep, unsigned length)
{
      struct usb_request      *req;

      req = usb_ep_alloc_request (ep, GFP_ATOMIC);
      if (req) {
            req->length = length;
            req->buf = kmalloc(length, GFP_ATOMIC);
            if (!req->buf) {
                  usb_ep_free_request (ep, req);
                  req = NULL;
            }
      }
      return req;
}

static void free_ep_req (struct usb_ep *ep, struct usb_request *req)
{
      kfree(req->buf);
      usb_ep_free_request (ep, req);
}

/*-------------------------------------------------------------------------*/

/*
 * SOURCE/SINK FUNCTION ... a primary testing vehicle for USB peripherals,
 * this just sinks bulk packets OUT to the peripheral and sources them IN
 * to the host, optionally with specific data patterns.
 *
 * In terms of control messaging, this supports all the standard requests
 * plus two that support control-OUT tests.
 *
 * Note that because this doesn't queue more than one request at a time,
 * some other function must be used to test queueing logic.  The network
 * link (g_ether) is probably the best option for that.
 */

/* optionally require specific source/sink data patterns  */

static int
check_read_data (
      struct zero_dev         *dev,
      struct usb_ep           *ep,
      struct usb_request      *req
)
{
      unsigned    i;
      u8          *buf = req->buf;

      for (i = 0; i < req->actual; i++, buf++) {
            switch (pattern) {
            /* all-zeroes has no synchronization issues */
            case 0:
                  if (*buf == 0)
                        continue;
                  break;
            /* mod63 stays in sync with short-terminated transfers,
             * or otherwise when host and gadget agree on how large
             * each usb transfer request should be.  resync is done
             * with set_interface or set_config.
             */
            case 1:
                  if (*buf == (u8)(i % 63))
                        continue;
                  break;
            }
            ERROR (dev, "bad OUT byte, buf [%d] = %d\n", i, *buf);
            usb_ep_set_halt (ep);
            return -EINVAL;
      }
      return 0;
}

static void reinit_write_data(struct usb_ep *ep, struct usb_request *req)
{
      unsigned    i;
      u8          *buf = req->buf;

      switch (pattern) {
      case 0:
            memset (req->buf, 0, req->length);
            break;
      case 1:
            for  (i = 0; i < req->length; i++)
                  *buf++ = (u8) (i % 63);
            break;
      }
}

/* if there is only one request in the queue, there'll always be an
 * irq delay between end of one request and start of the next.
 * that prevents using hardware dma queues.
 */
static void source_sink_complete (struct usb_ep *ep, struct usb_request *req)
{
      struct zero_dev   *dev = ep->driver_data;
      int         status = req->status;

      switch (status) {

      case 0:                       /* normal completion? */
            if (ep == dev->out_ep) {
                  check_read_data (dev, ep, req);
                  memset (req->buf, 0x55, req->length);
            } else
                  reinit_write_data(ep, req);
            break;

      /* this endpoint is normally active while we're configured */
      case -ECONNABORTED:           /* hardware forced ep reset */
      case -ECONNRESET:       /* request dequeued */
      case -ESHUTDOWN:        /* disconnect from host */
            VDBG (dev, "%s gone (%d), %d/%d\n", ep->name, status,
                        req->actual, req->length);
            if (ep == dev->out_ep)
                  check_read_data (dev, ep, req);
            free_ep_req (ep, req);
            return;

      case -EOVERFLOW:        /* buffer overrun on read means that
                               * we didn't provide a big enough
                               * buffer.
                               */
      default:
#if 1
            DBG (dev, "%s complete --> %d, %d/%d\n", ep->name,
                        status, req->actual, req->length);
#endif
      case -EREMOTEIO:        /* short read */
            break;
      }

      status = usb_ep_queue (ep, req, GFP_ATOMIC);
      if (status) {
            ERROR (dev, "kill %s:  resubmit %d bytes --> %d\n",
                        ep->name, req->length, status);
            usb_ep_set_halt (ep);
            /* FIXME recover later ... somehow */
      }
}

static struct usb_request *source_sink_start_ep(struct usb_ep *ep)
{
      struct usb_request      *req;
      int               status;

      req = alloc_ep_req (ep, buflen);
      if (!req)
            return NULL;

      memset (req->buf, 0, req->length);
      req->complete = source_sink_complete;

      if (strcmp (ep->name, EP_IN_NAME) == 0)
            reinit_write_data(ep, req);
      else
            memset (req->buf, 0x55, req->length);

      status = usb_ep_queue(ep, req, GFP_ATOMIC);
      if (status) {
            struct zero_dev   *dev = ep->driver_data;

            ERROR (dev, "start %s --> %d\n", ep->name, status);
            free_ep_req (ep, req);
            req = NULL;
      }

      return req;
}

static int set_source_sink_config(struct zero_dev *dev)
{
      int               result = 0;
      struct usb_ep           *ep;
      struct usb_gadget *gadget = dev->gadget;

      gadget_for_each_ep (ep, gadget) {
            const struct usb_endpoint_descriptor      *d;

            /* one endpoint writes (sources) zeroes in (to the host) */
            if (strcmp (ep->name, EP_IN_NAME) == 0) {
                  d = ep_desc (gadget, &hs_source_desc, &fs_source_desc);
                  result = usb_ep_enable (ep, d);
                  if (result == 0) {
                        ep->driver_data = dev;
                        if (source_sink_start_ep(ep) != NULL) {
                              dev->in_ep = ep;
                              continue;
                        }
                        usb_ep_disable (ep);
                        result = -EIO;
                  }

            /* one endpoint reads (sinks) anything out (from the host) */
            } else if (strcmp (ep->name, EP_OUT_NAME) == 0) {
                  d = ep_desc (gadget, &hs_sink_desc, &fs_sink_desc);
                  result = usb_ep_enable (ep, d);
                  if (result == 0) {
                        ep->driver_data = dev;
                        if (source_sink_start_ep(ep) != NULL) {
                              dev->out_ep = ep;
                              continue;
                        }
                        usb_ep_disable (ep);
                        result = -EIO;
                  }

            /* ignore any other endpoints */
            } else
                  continue;

            /* stop on error */
            ERROR (dev, "can't start %s, result %d\n", ep->name, result);
            break;
      }
      if (result == 0)
            DBG (dev, "buflen %d\n", buflen);

      /* caller is responsible for cleanup on error */
      return result;
}

/*-------------------------------------------------------------------------*/

static void loopback_complete (struct usb_ep *ep, struct usb_request *req)
{
      struct zero_dev   *dev = ep->driver_data;
      int         status = req->status;

      switch (status) {

      case 0:                       /* normal completion? */
            if (ep == dev->out_ep) {
                  /* loop this OUT packet back IN to the host */
                  req->zero = (req->actual < req->length);
                  req->length = req->actual;
                  status = usb_ep_queue (dev->in_ep, req, GFP_ATOMIC);
                  if (status == 0)
                        return;

                  /* "should never get here" */
                  ERROR (dev, "can't loop %s to %s: %d\n",
                        ep->name, dev->in_ep->name,
                        status);
            }

            /* queue the buffer for some later OUT packet */
            req->length = buflen;
            status = usb_ep_queue (dev->out_ep, req, GFP_ATOMIC);
            if (status == 0)
                  return;

            /* "should never get here" */
            /* FALLTHROUGH */

      default:
            ERROR (dev, "%s loop complete --> %d, %d/%d\n", ep->name,
                        status, req->actual, req->length);
            /* FALLTHROUGH */

      /* NOTE:  since this driver doesn't maintain an explicit record
       * of requests it submitted (just maintains qlen count), we
       * rely on the hardware driver to clean up on disconnect or
       * endpoint disable.
       */
      case -ECONNABORTED:           /* hardware forced ep reset */
      case -ECONNRESET:       /* request dequeued */
      case -ESHUTDOWN:        /* disconnect from host */
            free_ep_req (ep, req);
            return;
      }
}

static int set_loopback_config(struct zero_dev *dev)
{
      int               result = 0;
      struct usb_ep           *ep;
      struct usb_gadget *gadget = dev->gadget;

      gadget_for_each_ep (ep, gadget) {
            const struct usb_endpoint_descriptor      *d;

            /* one endpoint writes data back IN to the host */
            if (strcmp (ep->name, EP_IN_NAME) == 0) {
                  d = ep_desc (gadget, &hs_source_desc, &fs_source_desc);
                  result = usb_ep_enable (ep, d);
                  if (result == 0) {
                        ep->driver_data = dev;
                        dev->in_ep = ep;
                        continue;
                  }

            /* one endpoint just reads OUT packets */
            } else if (strcmp (ep->name, EP_OUT_NAME) == 0) {
                  d = ep_desc (gadget, &hs_sink_desc, &fs_sink_desc);
                  result = usb_ep_enable (ep, d);
                  if (result == 0) {
                        ep->driver_data = dev;
                        dev->out_ep = ep;
                        continue;
                  }

            /* ignore any other endpoints */
            } else
                  continue;

            /* stop on error */
            ERROR (dev, "can't enable %s, result %d\n", ep->name, result);
            break;
      }

      /* allocate a bunch of read buffers and queue them all at once.
       * we buffer at most 'qlen' transfers; fewer if any need more
       * than 'buflen' bytes each.
       */
      if (result == 0) {
            struct usb_request      *req;
            unsigned          i;

            ep = dev->out_ep;
            for (i = 0; i < qlen && result == 0; i++) {
                  req = alloc_ep_req (ep, buflen);
                  if (req) {
                        req->complete = loopback_complete;
                        result = usb_ep_queue (ep, req, GFP_ATOMIC);
                        if (result)
                              DBG (dev, "%s queue req --> %d\n",
                                          ep->name, result);
                  } else
                        result = -ENOMEM;
            }
      }
      if (result == 0)
            DBG (dev, "qlen %d, buflen %d\n", qlen, buflen);

      /* caller is responsible for cleanup on error */
      return result;
}

/*-------------------------------------------------------------------------*/

static void zero_reset_config (struct zero_dev *dev)
{
      if (dev->config == 0)
            return;

      DBG (dev, "reset config\n");

      /* just disable endpoints, forcing completion of pending i/o.
       * all our completion handlers free their requests in this case.
       */
      if (dev->in_ep) {
            usb_ep_disable (dev->in_ep);
            dev->in_ep = NULL;
      }
      if (dev->out_ep) {
            usb_ep_disable (dev->out_ep);
            dev->out_ep = NULL;
      }
      dev->config = 0;
      del_timer (&dev->resume);
}

/* change our operational config.  this code must agree with the code
 * that returns config descriptors, and altsetting code.
 *
 * it's also responsible for power management interactions. some
 * configurations might not work with our current power sources.
 *
 * note that some device controller hardware will constrain what this
 * code can do, perhaps by disallowing more than one configuration or
 * by limiting configuration choices (like the pxa2xx).
 */
static int zero_set_config(struct zero_dev *dev, unsigned number)
{
      int               result = 0;
      struct usb_gadget *gadget = dev->gadget;

      if (number == dev->config)
            return 0;

      if (gadget_is_sa1100 (gadget) && dev->config) {
            /* tx fifo is full, but we can't clear it...*/
            ERROR(dev, "can't change configurations\n");
            return -ESPIPE;
      }
      zero_reset_config (dev);

      switch (number) {
      case CONFIG_SOURCE_SINK:
            result = set_source_sink_config(dev);
            break;
      case CONFIG_LOOPBACK:
            result = set_loopback_config(dev);
            break;
      default:
            result = -EINVAL;
            /* FALL THROUGH */
      case 0:
            return result;
      }

      if (!result && (!dev->in_ep || !dev->out_ep))
            result = -ENODEV;
      if (result)
            zero_reset_config (dev);
      else {
            char *speed;

            switch (gadget->speed) {
            case USB_SPEED_LOW:     speed = "low"; break;
            case USB_SPEED_FULL:    speed = "full"; break;
            case USB_SPEED_HIGH:    speed = "high"; break;
            default:          speed = "?"; break;
            }

            dev->config = number;
            INFO (dev, "%s speed config #%d: %s\n", speed, number,
                        (number == CONFIG_SOURCE_SINK)
                              ? source_sink : loopback);
      }
      return result;
}

/*-------------------------------------------------------------------------*/

static void zero_setup_complete (struct usb_ep *ep, struct usb_request *req)
{
      if (req->status || req->actual != req->length)
            DBG ((struct zero_dev *) ep->driver_data,
                        "setup complete --> %d, %d/%d\n",
                        req->status, req->actual, req->length);
}

/*
 * The setup() callback implements all the ep0 functionality that's
 * not handled lower down, in hardware or the hardware driver (like
 * device and endpoint feature flags, and their status).  It's all
 * housekeeping for the gadget function we're implementing.  Most of
 * the work is in config-specific setup.
 */
static int
zero_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
{
      struct zero_dev         *dev = get_gadget_data (gadget);
      struct usb_request      *req = dev->req;
      int               value = -EOPNOTSUPP;
      u16               w_index = le16_to_cpu(ctrl->wIndex);
      u16               w_value = le16_to_cpu(ctrl->wValue);
      u16               w_length = le16_to_cpu(ctrl->wLength);

      /* usually this stores reply data in the pre-allocated ep0 buffer,
       * but config change events will reconfigure hardware.
       */
      req->zero = 0;
      switch (ctrl->bRequest) {

      case USB_REQ_GET_DESCRIPTOR:
            if (ctrl->bRequestType != USB_DIR_IN)
                  goto unknown;
            switch (w_value >> 8) {

            case USB_DT_DEVICE:
                  value = min (w_length, (u16) sizeof device_desc);
                  memcpy (req->buf, &device_desc, value);
                  break;
            case USB_DT_DEVICE_QUALIFIER:
                  if (!gadget_is_dualspeed(gadget))
                        break;
                  value = min (w_length, (u16) sizeof dev_qualifier);
                  memcpy (req->buf, &dev_qualifier, value);
                  break;

            case USB_DT_OTHER_SPEED_CONFIG:
                  if (!gadget_is_dualspeed(gadget))
                        break;
                  // FALLTHROUGH
            case USB_DT_CONFIG:
                  value = config_buf (gadget, req->buf,
                              w_value >> 8,
                              w_value & 0xff);
                  if (value >= 0)
                        value = min (w_length, (u16) value);
                  break;

            case USB_DT_STRING:
                  /* wIndex == language code.
                   * this driver only handles one language, you can
                   * add string tables for other languages, using
                   * any UTF-8 characters
                   */
                  value = usb_gadget_get_string (&stringtab,
                              w_value & 0xff, req->buf);
                  if (value >= 0)
                        value = min (w_length, (u16) value);
                  break;
            }
            break;

      /* currently two configs, two speeds */
      case USB_REQ_SET_CONFIGURATION:
            if (ctrl->bRequestType != 0)
                  goto unknown;
            if (gadget->a_hnp_support)
                  DBG (dev, "HNP available\n");
            else if (gadget->a_alt_hnp_support)
                  DBG (dev, "HNP needs a different root port\n");
            else
                  VDBG (dev, "HNP inactive\n");
            spin_lock (&dev->lock);
            value = zero_set_config(dev, w_value);
            spin_unlock (&dev->lock);
            break;
      case USB_REQ_GET_CONFIGURATION:
            if (ctrl->bRequestType != USB_DIR_IN)
                  goto unknown;
            *(u8 *)req->buf = dev->config;
            value = min (w_length, (u16) 1);
            break;

      /* until we add altsetting support, or other interfaces,
       * only 0/0 are possible.  pxa2xx only supports 0/0 (poorly)
       * and already killed pending endpoint I/O.
       */
      case USB_REQ_SET_INTERFACE:
            if (ctrl->bRequestType != USB_RECIP_INTERFACE)
                  goto unknown;
            spin_lock (&dev->lock);
            if (dev->config && w_index == 0 && w_value == 0) {
                  u8          config = dev->config;

                  /* resets interface configuration, forgets about
                   * previous transaction state (queued bufs, etc)
                   * and re-inits endpoint state (toggle etc)
                   * no response queued, just zero status == success.
                   * if we had more than one interface we couldn't
                   * use this "reset the config" shortcut.
                   */
                  zero_reset_config (dev);
                  zero_set_config(dev, config);
                  value = 0;
            }
            spin_unlock (&dev->lock);
            break;
      case USB_REQ_GET_INTERFACE:
            if (ctrl->bRequestType != (USB_DIR_IN|USB_RECIP_INTERFACE))
                  goto unknown;
            if (!dev->config)
                  break;
            if (w_index != 0) {
                  value = -EDOM;
                  break;
            }
            *(u8 *)req->buf = 0;
            value = min (w_length, (u16) 1);
            break;

      /*
       * These are the same vendor-specific requests supported by
       * Intel's USB 2.0 compliance test devices.  We exceed that
       * device spec by allowing multiple-packet requests.
       */
      case 0x5b:  /* control WRITE test -- fill the buffer */
            if (ctrl->bRequestType != (USB_DIR_OUT|USB_TYPE_VENDOR))
                  goto unknown;
            if (w_value || w_index)
                  break;
            /* just read that many bytes into the buffer */
            if (w_length > USB_BUFSIZ)
                  break;
            value = w_length;
            break;
      case 0x5c:  /* control READ test -- return the buffer */
            if (ctrl->bRequestType != (USB_DIR_IN|USB_TYPE_VENDOR))
                  goto unknown;
            if (w_value || w_index)
                  break;
            /* expect those bytes are still in the buffer; send back */
            if (w_length > USB_BUFSIZ
                        || w_length != req->length)
                  break;
            value = w_length;
            break;

      default:
unknown:
            VDBG (dev,
                  "unknown control req%02x.%02x v%04x i%04x l%d\n",
                  ctrl->bRequestType, ctrl->bRequest,
                  w_value, w_index, w_length);
      }

      /* respond with data transfer before status phase? */
      if (value >= 0) {
            req->length = value;
            req->zero = value < w_length;
            value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
            if (value < 0) {
                  DBG (dev, "ep_queue --> %d\n", value);
                  req->status = 0;
                  zero_setup_complete (gadget->ep0, req);
            }
      }

      /* device either stalls (value < 0) or reports success */
      return value;
}

static void
zero_disconnect (struct usb_gadget *gadget)
{
      struct zero_dev         *dev = get_gadget_data (gadget);
      unsigned long           flags;

      spin_lock_irqsave (&dev->lock, flags);
      zero_reset_config (dev);

      /* a more significant application might have some non-usb
       * activities to quiesce here, saving resources like power
       * or pushing the notification up a network stack.
       */
      spin_unlock_irqrestore (&dev->lock, flags);

      /* next we may get setup() calls to enumerate new connections;
       * or an unbind() during shutdown (including removing module).
       */
}

static void
zero_autoresume (unsigned long _dev)
{
      struct zero_dev   *dev = (struct zero_dev *) _dev;
      int         status;

      /* normally the host would be woken up for something
       * more significant than just a timer firing...
       */
      if (dev->gadget->speed != USB_SPEED_UNKNOWN) {
            status = usb_gadget_wakeup (dev->gadget);
            DBG (dev, "wakeup --> %d\n", status);
      }
}

/*-------------------------------------------------------------------------*/

static void /* __init_or_exit */
zero_unbind (struct usb_gadget *gadget)
{
      struct zero_dev         *dev = get_gadget_data (gadget);

      DBG (dev, "unbind\n");

      /* we've already been disconnected ... no i/o is active */
      if (dev->req) {
            dev->req->length = USB_BUFSIZ;
            free_ep_req (gadget->ep0, dev->req);
      }
      del_timer_sync (&dev->resume);
      kfree (dev);
      set_gadget_data (gadget, NULL);
}

static int __init
zero_bind (struct usb_gadget *gadget)
{
      struct zero_dev         *dev;
      struct usb_ep           *ep;
      int               gcnum;

      /* FIXME this can't yet work right with SH ... it has only
       * one configuration, numbered one.
       */
      if (gadget_is_sh(gadget))
            return -ENODEV;

      /* Bulk-only drivers like this one SHOULD be able to
       * autoconfigure on any sane usb controller driver,
       * but there may also be important quirks to address.
       */
      usb_ep_autoconfig_reset (gadget);
      ep = usb_ep_autoconfig (gadget, &fs_source_desc);
      if (!ep) {
autoconf_fail:
            printk (KERN_ERR "%s: can't autoconfigure on %s\n",
                  shortname, gadget->name);
            return -ENODEV;
      }
      EP_IN_NAME = ep->name;
      ep->driver_data = ep;   /* claim */

      ep = usb_ep_autoconfig (gadget, &fs_sink_desc);
      if (!ep)
            goto autoconf_fail;
      EP_OUT_NAME = ep->name;
      ep->driver_data = ep;   /* claim */

      gcnum = usb_gadget_controller_number (gadget);
      if (gcnum >= 0)
            device_desc.bcdDevice = cpu_to_le16 (0x0200 + gcnum);
      else {
            /* gadget zero is so simple (for now, no altsettings) that
             * it SHOULD NOT have problems with bulk-capable hardware.
             * so warn about unrcognized controllers, don't panic.
             *
             * things like configuration and altsetting numbering
             * can need hardware-specific attention though.
             */
            printk (KERN_WARNING "%s: controller '%s' not recognized\n",
                  shortname, gadget->name);
            device_desc.bcdDevice = __constant_cpu_to_le16 (0x9999);
      }


      /* ok, we made sense of the hardware ... */
      dev = kzalloc(sizeof(*dev), GFP_KERNEL);
      if (!dev)
            return -ENOMEM;
      spin_lock_init (&dev->lock);
      dev->gadget = gadget;
      set_gadget_data (gadget, dev);

      /* preallocate control response and buffer */
      dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
      if (!dev->req)
            goto enomem;
      dev->req->buf = kmalloc(USB_BUFSIZ, GFP_KERNEL);
      if (!dev->req->buf)
            goto enomem;

      dev->req->complete = zero_setup_complete;

      device_desc.bMaxPacketSize0 = gadget->ep0->maxpacket;

      if (gadget_is_dualspeed(gadget)) {
            /* assume ep0 uses the same value for both speeds ... */
            dev_qualifier.bMaxPacketSize0 = device_desc.bMaxPacketSize0;

            /* and that all endpoints are dual-speed */
            hs_source_desc.bEndpointAddress =
                        fs_source_desc.bEndpointAddress;
            hs_sink_desc.bEndpointAddress =
                        fs_sink_desc.bEndpointAddress;
      }

      if (gadget_is_otg(gadget)) {
            otg_descriptor.bmAttributes |= USB_OTG_HNP,
            source_sink_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
            loopback_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
      }

      usb_gadget_set_selfpowered (gadget);

      init_timer (&dev->resume);
      dev->resume.function = zero_autoresume;
      dev->resume.data = (unsigned long) dev;
      if (autoresume) {
            source_sink_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
            loopback_config.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
      }

      gadget->ep0->driver_data = dev;

      INFO (dev, "%s, version: " DRIVER_VERSION "\n", longname);
      INFO (dev, "using %s, OUT %s IN %s\n", gadget->name,
            EP_OUT_NAME, EP_IN_NAME);

      snprintf (manufacturer, sizeof manufacturer, "%s %s with %s",
            init_utsname()->sysname, init_utsname()->release,
            gadget->name);

      return 0;

enomem:
      zero_unbind (gadget);
      return -ENOMEM;
}

/*-------------------------------------------------------------------------*/

static void
zero_suspend (struct usb_gadget *gadget)
{
      struct zero_dev         *dev = get_gadget_data (gadget);

      if (gadget->speed == USB_SPEED_UNKNOWN)
            return;

      if (autoresume) {
            mod_timer (&dev->resume, jiffies + (HZ * autoresume));
            DBG (dev, "suspend, wakeup in %d seconds\n", autoresume);
      } else
            DBG (dev, "suspend\n");
}

static void
zero_resume (struct usb_gadget *gadget)
{
      struct zero_dev         *dev = get_gadget_data (gadget);

      DBG (dev, "resume\n");
      del_timer (&dev->resume);
}


/*-------------------------------------------------------------------------*/

static struct usb_gadget_driver zero_driver = {
#ifdef CONFIG_USB_GADGET_DUALSPEED
      .speed            = USB_SPEED_HIGH,
#else
      .speed            = USB_SPEED_FULL,
#endif
      .function   = (char *) longname,
      .bind       = zero_bind,
      .unbind           = __exit_p(zero_unbind),

      .setup            = zero_setup,
      .disconnect = zero_disconnect,

      .suspend    = zero_suspend,
      .resume           = zero_resume,

      .driver           = {
            .name       = (char *) shortname,
            .owner            = THIS_MODULE,
      },
};

MODULE_AUTHOR("David Brownell");
MODULE_LICENSE("GPL");


static int __init init (void)
{
      return usb_gadget_register_driver (&zero_driver);
}
module_init (init);

static void __exit cleanup (void)
{
      usb_gadget_unregister_driver (&zero_driver);
}
module_exit (cleanup);


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