/*
   * 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 <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,
  };
  
  /*-------------------------------------------------------------------------*/
  
  /* 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 =		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,
  };
  
  static const struct usb_descriptor_header *otg_desc[] = {
  	(struct usb_descriptor_header *) &otg_descriptor,
  	NULL,
  };
  #else
  #define otg_desc	NULL
  #endif
  
  /* 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 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
  ", __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
  ",
  			autoresume_step_ms);
  
  		autoresume_step_ms += autoresume_interval_ms;
  	} else
  		DBG(cdev, "%s
  ", __func__);
  }
  
  static void zero_resume(struct usb_composite_dev *cdev)
  {
  	DBG(cdev, "%s
  ", __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");
  
  static int __init 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;
  
  	setup_timer(&autoresume_timer, zero_autoresume, (unsigned long) cdev);
  
  	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;
  
  	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)) {
  		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_conf_flb;
  
  	usb_ep_autoconfig_reset(cdev->gadget);
  	status = usb_add_function(&loopback_driver, func_lb);
  	if (status)
  		goto err_conf_flb;
  
  	usb_ep_autoconfig_reset(cdev->gadget);
  	usb_composite_overwrite_options(cdev, &coverwrite);
  
  	INFO(cdev, "%s, version: " DRIVER_VERSION "
  ", longname);
  
  	return 0;
  
  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);
  	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);
  }
  late_initcall(init);
  
  static void __exit cleanup(void)
  {
  	usb_composite_unregister(&zero_driver);
  }
  module_exit(cleanup);