zero.c

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/*
 * zero.c -- Gadget Zero, for USB development
 *
 * Copyright (C) 2003-2008 David Brownell
 * Copyright (C) 2008 by Nokia Corporation
 *
 * 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.
 */


/*
 * 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.
 * Some hardware details are visible, 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.
 *
 * 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.
 */

/*
 * driver assumes self-powered hardware, and
 * has no way for users to trigger remote wakeup.
 */

/* #define VERBOSE_DEBUG */

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

#include "g_zero.h"
#include "gadget_chips.h"


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

/*
 * Kbuild is not very cooperative with respect to linking separately
 * compiled library objects into one module.  So for now we won't use
 * separate compilation ... ensuring init/exit sections work to shrink
 * the runtime footprint, and giving us at least some parts of what
 * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
 */
#include "f_sourcesink.c"
#include "f_loopback.c"

/*-------------------------------------------------------------------------*/
USB_GADGET_COMPOSITE_OPTIONS();

#define DRIVER_VERSION      "Cinco de Mayo 2008"

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

unsigned buflen = 4096;     /* only used for bulk endpoints */
module_param(buflen, 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 original superh) that only support one config.
 */
static bool 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" */
#define DEFAULT_AUTORESUME  0
#else
#define DRIVER_VENDOR_NUM   0x1a0a      /* OTG test device IDs */
#define DRIVER_PRODUCT_NUM  0xbadd
#define DEFAULT_AUTORESUME  5
#endif

/* If the optional "autoresume" mode is enabled, it provides good
 * functional coverage for the "USBCV" test harness from USB-IF.
 * It's always set if OTG mode is enabled.
 */
unsigned autoresume = DEFAULT_AUTORESUME;
module_param(autoresume, uint, S_IRUGO);
MODULE_PARM_DESC(autoresume, "zero, or seconds before remote wakeup");

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

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

    .bcdUSB =       cpu_to_le16(0x0200),
    .bDeviceClass =     USB_CLASS_VENDOR_SPEC,

    .idVendor =     cpu_to_le16(DRIVER_VENDOR_NUM),
    .idProduct =        cpu_to_le16(DRIVER_PRODUCT_NUM),
    .bNumConfigurations =   2,
};

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

    /* REVISIT SRP-only hardware is possible, although
     * it would not be called "OTG" ...
     */
    .bmAttributes =     USB_OTG_SRP | USB_OTG_HNP,
};

const struct usb_descriptor_header *otg_desc[] = {
    (struct usb_descriptor_header *) &otg_descriptor,
    NULL,
};
#endif

/* string IDs are assigned dynamically */
/* default serial number takes at least two packets */
static char serial[] = "0123456789.0123456789.0123456789";

static struct usb_string strings_dev[] = {
    [USB_GADGET_MANUFACTURER_IDX].s = "",
    [USB_GADGET_PRODUCT_IDX].s = longname,
    [USB_GADGET_SERIAL_IDX].s = serial,
    {  }            /* end of list */
};

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

static struct usb_gadget_strings *dev_strings[] = {
    &stringtab_dev,
    NULL,
};

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

struct usb_request *alloc_ep_req(struct usb_ep *ep, int len)
{
    struct usb_request  *req;

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

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

static void disable_ep(struct usb_composite_dev *cdev, struct usb_ep *ep)
{
    int         value;

    if (ep->driver_data) {
        value = usb_ep_disable(ep);
        if (value < 0)
            DBG(cdev, "disable %s --> %d\n",
                    ep->name, value);
        ep->driver_data = NULL;
    }
}

void disable_endpoints(struct usb_composite_dev *cdev,
        struct usb_ep *in, struct usb_ep *out,
        struct usb_ep *iso_in, struct usb_ep *iso_out)
{
    disable_ep(cdev, in);
    disable_ep(cdev, out);
    if (iso_in)
        disable_ep(cdev, iso_in);
    if (iso_out)
        disable_ep(cdev, iso_out);
}

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

static struct timer_list    autoresume_timer;

static void zero_autoresume(unsigned long _c)
{
    struct usb_composite_dev    *cdev = (void *)_c;
    struct usb_gadget       *g = cdev->gadget;

    /* unconfigured devices can't issue wakeups */
    if (!cdev->config)
        return;

    /* Normally the host would be woken up for something
     * more significant than just a timer firing; likely
     * because of some direct user request.
     */
    if (g->speed != USB_SPEED_UNKNOWN) {
        int status = usb_gadget_wakeup(g);
        INFO(cdev, "%s --> %d\n", __func__, status);
    }
}

static void zero_suspend(struct usb_composite_dev *cdev)
{
    if (cdev->gadget->speed == USB_SPEED_UNKNOWN)
        return;

    if (autoresume) {
        mod_timer(&autoresume_timer, jiffies + (HZ * autoresume));
        DBG(cdev, "suspend, wakeup in %d seconds\n", autoresume);
    } else
        DBG(cdev, "%s\n", __func__);
}

static void zero_resume(struct usb_composite_dev *cdev)
{
    DBG(cdev, "%s\n", __func__);
    del_timer(&autoresume_timer);
}

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

static int __init zero_bind(struct usb_composite_dev *cdev)
{
    int         status;

    /* Allocate string descriptor numbers ... note that string
     * contents can be overridden by the composite_dev glue.
     */
    status = usb_string_ids_tab(cdev, strings_dev);
    if (status < 0)
        return status;

    device_desc.iManufacturer = strings_dev[USB_GADGET_MANUFACTURER_IDX].id;
    device_desc.iProduct = strings_dev[USB_GADGET_PRODUCT_IDX].id;
    device_desc.iSerialNumber = strings_dev[USB_GADGET_SERIAL_IDX].id;

    setup_timer(&autoresume_timer, zero_autoresume, (unsigned long) cdev);

    /* Register primary, then secondary configuration.  Note that
     * SH3 only allows one config...
     */
    if (loopdefault) {
        loopback_add(cdev, autoresume != 0);
        sourcesink_add(cdev, autoresume != 0);
    } else {
        sourcesink_add(cdev, autoresume != 0);
        loopback_add(cdev, autoresume != 0);
    }

    usb_composite_overwrite_options(cdev, &coverwrite);

    INFO(cdev, "%s, version: " DRIVER_VERSION "\n", longname);

    return 0;
}

static int zero_unbind(struct usb_composite_dev *cdev)
{
    del_timer_sync(&autoresume_timer);
    return 0;
}

static __refdata struct usb_composite_driver zero_driver = {
    .name       = "zero",
    .dev        = &device_desc,
    .strings    = dev_strings,
    .max_speed  = USB_SPEED_SUPER,
    .bind       = zero_bind,
    .unbind     = zero_unbind,
    .suspend    = zero_suspend,
    .resume     = zero_resume,
};

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

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

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