// SPDX-License-Identifier: GPL-2.0+
/*
 * zero.c -- Gadget Zero, for USB development
 *
 * Copyright (C) 2003-2008 David Brownell
 * Copyright (C) 2008 by Nokia Corporation
 */

/*
 * 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 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 infrastructure 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 <linux/module.h>
#include <linux/err.h>
#include <linux/usb/composite.h>

#include "g_zero.h"
/*-------------------------------------------------------------------------*/
USB_GADGET_COMPOSITE_OPTIONS();

#define DRIVER_VERSION          "Cinco de Mayo 2008"

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

/*
 * 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);

static struct usb_zero_options gzero_options = {
        .isoc_interval = GZERO_ISOC_INTERVAL,
        .isoc_maxpacket = GZERO_ISOC_MAXPACKET,
        .bulk_buflen = GZERO_BULK_BUFLEN,
        .qlen = GZERO_QLEN,
        .ss_bulk_qlen = GZERO_SS_BULK_QLEN,
        .ss_iso_qlen = GZERO_SS_ISO_QLEN,
};

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

/* 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.
 */
static unsigned autoresume = DEFAULT_AUTORESUME;
module_param(autoresume, uint, S_IRUGO);
MODULE_PARM_DESC(autoresume, "zero, or seconds before remote wakeup");

/* Maximum Autoresume time */
static unsigned max_autoresume;
module_param(max_autoresume, uint, S_IRUGO);
MODULE_PARM_DESC(max_autoresume, "maximum seconds before remote wakeup");

/* Interval between two remote wakeups */
static unsigned autoresume_interval_ms;
module_param(autoresume_interval_ms, uint, S_IRUGO);
MODULE_PARM_DESC(autoresume_interval_ms,
                "milliseconds to increase successive wakeup delays");

static unsigned autoresume_step_ms;
/*-------------------------------------------------------------------------*/

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

        /* .bcdUSB = DYNAMIC */
        .bDeviceClass =         USB_CLASS_VENDOR_SPEC,

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

static const struct usb_descriptor_header *otg_desc[2];

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

#define USB_GZERO_SS_DESC       (USB_GADGET_FIRST_AVAIL_IDX + 0)
#define USB_GZERO_LB_DESC       (USB_GADGET_FIRST_AVAIL_IDX + 1)

static struct usb_string strings_dev[] = {
        [USB_GADGET_MANUFACTURER_IDX].s = "",
        [USB_GADGET_PRODUCT_IDX].s = longname,
        [USB_GADGET_SERIAL_IDX].s = serial,
        [USB_GZERO_SS_DESC].s   = "source and sink data",
        [USB_GZERO_LB_DESC].s   = "loop input to output",
        {  }                    /* 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,
};

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

static struct timer_list        autoresume_timer;
static struct usb_composite_dev *autoresume_cdev;

static void zero_autoresume(struct timer_list *unused)
{
        struct usb_composite_dev        *cdev = autoresume_cdev;
        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) {
                if (max_autoresume &&
                        (autoresume_step_ms > max_autoresume * 1000))
                                autoresume_step_ms = autoresume * 1000;

                mod_timer(&autoresume_timer, jiffies +
                        msecs_to_jiffies(autoresume_step_ms));
                DBG(cdev, "suspend, wakeup in %d milliseconds\n",
                        autoresume_step_ms);

                autoresume_step_ms += autoresume_interval_ms;
        } 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 struct usb_configuration loopback_driver = {
        .label          = "loopback",
        .bConfigurationValue = 2,
        .bmAttributes   = USB_CONFIG_ATT_SELFPOWER,
        /* .iConfiguration = DYNAMIC */
};

static struct usb_function *func_ss;
static struct usb_function_instance *func_inst_ss;

static int ss_config_setup(struct usb_configuration *c,
                const struct usb_ctrlrequest *ctrl)
{
        switch (ctrl->bRequest) {
        case 0x5b:
        case 0x5c:
                return func_ss->setup(func_ss, ctrl);
        default:
                return -EOPNOTSUPP;
        }
}

static struct usb_configuration sourcesink_driver = {
        .label                  = "source/sink",
        .setup                  = ss_config_setup,
        .bConfigurationValue    = 3,
        .bmAttributes           = USB_CONFIG_ATT_SELFPOWER,
        /* .iConfiguration      = DYNAMIC */
};

module_param_named(buflen, gzero_options.bulk_buflen, uint, 0);
module_param_named(pattern, gzero_options.pattern, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(pattern, "0 = all zeroes, 1 = mod63, 2 = none");

module_param_named(isoc_interval, gzero_options.isoc_interval, uint,
                S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(isoc_interval, "1 - 16");

module_param_named(isoc_maxpacket, gzero_options.isoc_maxpacket, uint,
                S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(isoc_maxpacket, "0 - 1023 (fs), 0 - 1024 (hs/ss)");

module_param_named(isoc_mult, gzero_options.isoc_mult, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(isoc_mult, "0 - 2 (hs/ss only)");

module_param_named(isoc_maxburst, gzero_options.isoc_maxburst, uint,
                S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(isoc_maxburst, "0 - 15 (ss only)");

static struct usb_function *func_lb;
static struct usb_function_instance *func_inst_lb;

module_param_named(qlen, gzero_options.qlen, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(qlen, "depth of loopback queue");

module_param_named(ss_bulk_qlen, gzero_options.ss_bulk_qlen, uint,
                S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(bulk_qlen, "depth of sourcesink queue for bulk transfer");

module_param_named(ss_iso_qlen, gzero_options.ss_iso_qlen, uint,
                S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(iso_qlen, "depth of sourcesink queue for iso transfer");

static int zero_bind(struct usb_composite_dev *cdev)
{
        struct f_ss_opts        *ss_opts;
        struct f_lb_opts        *lb_opts;
        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;

        autoresume_cdev = cdev;
        timer_setup(&autoresume_timer, zero_autoresume, 0);

        func_inst_ss = usb_get_function_instance("SourceSink");
        if (IS_ERR(func_inst_ss))
                return PTR_ERR(func_inst_ss);

        ss_opts =  container_of(func_inst_ss, struct f_ss_opts, func_inst);
        ss_opts->pattern = gzero_options.pattern;
        ss_opts->isoc_interval = gzero_options.isoc_interval;
        ss_opts->isoc_maxpacket = gzero_options.isoc_maxpacket;
        ss_opts->isoc_mult = gzero_options.isoc_mult;
        ss_opts->isoc_maxburst = gzero_options.isoc_maxburst;
        ss_opts->bulk_buflen = gzero_options.bulk_buflen;
        ss_opts->bulk_qlen = gzero_options.ss_bulk_qlen;
        ss_opts->iso_qlen = gzero_options.ss_iso_qlen;

        func_ss = usb_get_function(func_inst_ss);
        if (IS_ERR(func_ss)) {
                status = PTR_ERR(func_ss);
                goto err_put_func_inst_ss;
        }

        func_inst_lb = usb_get_function_instance("Loopback");
        if (IS_ERR(func_inst_lb)) {
                status = PTR_ERR(func_inst_lb);
                goto err_put_func_ss;
        }

        lb_opts = container_of(func_inst_lb, struct f_lb_opts, func_inst);
        lb_opts->bulk_buflen = gzero_options.bulk_buflen;
        lb_opts->qlen = gzero_options.qlen;

        func_lb = usb_get_function(func_inst_lb);
        if (IS_ERR(func_lb)) {
                status = PTR_ERR(func_lb);
                goto err_put_func_inst_lb;
        }

        sourcesink_driver.iConfiguration = strings_dev[USB_GZERO_SS_DESC].id;
        loopback_driver.iConfiguration = strings_dev[USB_GZERO_LB_DESC].id;

        /* support autoresume for remote wakeup testing */
        sourcesink_driver.bmAttributes &= ~USB_CONFIG_ATT_WAKEUP;
        loopback_driver.bmAttributes &= ~USB_CONFIG_ATT_WAKEUP;
        sourcesink_driver.descriptors = NULL;
        loopback_driver.descriptors = NULL;
        if (autoresume) {
                sourcesink_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
                loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
                autoresume_step_ms = autoresume * 1000;
        }

        /* support OTG systems */
        if (gadget_is_otg(cdev->gadget)) {
                if (!otg_desc[0]) {
                        struct usb_descriptor_header *usb_desc;

                        usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
                        if (!usb_desc) {
                                status = -ENOMEM;
                                goto err_conf_flb;
                        }
                        usb_otg_descriptor_init(cdev->gadget, usb_desc);
                        otg_desc[0] = usb_desc;
                        otg_desc[1] = NULL;
                }
                sourcesink_driver.descriptors = otg_desc;
                sourcesink_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
                loopback_driver.descriptors = otg_desc;
                loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
        }

        /* Register primary, then secondary configuration.  Note that
         * SH3 only allows one config...
         */
        if (loopdefault) {
                usb_add_config_only(cdev, &loopback_driver);
                usb_add_config_only(cdev, &sourcesink_driver);
        } else {
                usb_add_config_only(cdev, &sourcesink_driver);
                usb_add_config_only(cdev, &loopback_driver);
        }
        status = usb_add_function(&sourcesink_driver, func_ss);
        if (status)
                goto err_free_otg_desc;

        usb_ep_autoconfig_reset(cdev->gadget);
        status = usb_add_function(&loopback_driver, func_lb);
        if (status)
                goto err_free_otg_desc;

        usb_ep_autoconfig_reset(cdev->gadget);
        usb_composite_overwrite_options(cdev, &coverwrite);

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

        return 0;

err_free_otg_desc:
        kfree(otg_desc[0]);
        otg_desc[0] = NULL;
err_conf_flb:
        usb_put_function(func_lb);
        func_lb = NULL;
err_put_func_inst_lb:
        usb_put_function_instance(func_inst_lb);
        func_inst_lb = NULL;
err_put_func_ss:
        usb_put_function(func_ss);
        func_ss = NULL;
err_put_func_inst_ss:
        usb_put_function_instance(func_inst_ss);
        func_inst_ss = NULL;
        return status;
}

static int zero_unbind(struct usb_composite_dev *cdev)
{
        del_timer_sync(&autoresume_timer);
        if (!IS_ERR_OR_NULL(func_ss))
                usb_put_function(func_ss);
        usb_put_function_instance(func_inst_ss);
        if (!IS_ERR_OR_NULL(func_lb))
                usb_put_function(func_lb);
        usb_put_function_instance(func_inst_lb);
        kfree(otg_desc[0]);
        otg_desc[0] = NULL;

        return 0;
}

static 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_usb_composite_driver(zero_driver);

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