/*
 * 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/utsname.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 "composite.c"
#include "usbstring.c"
#include "config.c"
#include "epautoconf.c"

#include "f_sourcesink.c"
#include "f_loopback.c"

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

#define DRIVER_VERSION          "Cinco de Mayo 2008"

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

unsigned buflen = 4096;
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 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" */
#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 */

#define STRING_MANUFACTURER_IDX         0
#define STRING_PRODUCT_IDX              1
#define STRING_SERIAL_IDX               2

static char manufacturer[50];

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

static struct usb_string strings_dev[] = {
        [STRING_MANUFACTURER_IDX].s = manufacturer,
        [STRING_PRODUCT_IDX].s = longname,
        [STRING_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)
{
        struct usb_request      *req;

        req = usb_ep_alloc_request(ep, GFP_ATOMIC);
        if (req) {
                req->length = buflen;
                req->buf = kmalloc(buflen, 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)
{
        disable_ep(cdev, in);
        disable_ep(cdev, 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                     gcnum;
        struct usb_gadget       *gadget = cdev->gadget;
        int                     id;

        /* Allocate string descriptor numbers ... note that string
         * contents can be overridden by the composite_dev glue.
         */
        id = usb_string_id(cdev);
        if (id < 0)
                return id;
        strings_dev[STRING_MANUFACTURER_IDX].id = id;
        device_desc.iManufacturer = id;

        id = usb_string_id(cdev);
        if (id < 0)
                return id;
        strings_dev[STRING_PRODUCT_IDX].id = id;
        device_desc.iProduct = id;

        id = usb_string_id(cdev);
        if (id < 0)
                return id;
        strings_dev[STRING_SERIAL_IDX].id = id;
        device_desc.iSerialNumber = 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);
        }

        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 just warn about unrcognized controllers -- don't panic.
                 *
                 * things like configuration and altsetting numbering
                 * can need hardware-specific attention though.
                 */
                pr_warning("%s: controller '%s' not recognized\n",
                        longname, gadget->name);
                device_desc.bcdDevice = cpu_to_le16(0x9999);
        }


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

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

        return 0;
}

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

static struct usb_composite_driver zero_driver = {
        .name           = "zero",
        .dev            = &device_desc,
        .strings        = dev_strings,
        .max_speed      = USB_SPEED_SUPER,
        .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, zero_bind);
}
module_init(init);

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