serial.c

/*
 * serial.c -- USB gadget serial driver
 *
 * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
 * Copyright (C) 2008 by David Brownell
 * Copyright (C) 2008 by Nokia Corporation
 *
 * This software is distributed under the terms of the GNU General
 * Public License ("GPL") as published by the Free Software Foundation,
 * either version 2 of that License or (at your option) any later version.
 */

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

#include "u_serial.h"
#include "gadget_chips.h"


/* Defines */

#define GS_VERSION_STR			"v2.4"
#define GS_VERSION_NUM			0x2400

#define GS_LONG_NAME			"Gadget Serial"
#define GS_VERSION_NAME			GS_LONG_NAME " " GS_VERSION_STR

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

/* 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.
*/
#define GS_VENDOR_ID			0x0525	/* NetChip */
#define GS_PRODUCT_ID			0xa4a6	/* Linux-USB Serial Gadget */
#define GS_CDC_PRODUCT_ID		0xa4a7	/* ... as CDC-ACM */

/* string IDs are assigned dynamically */

#define STRING_MANUFACTURER_IDX		0
#define STRING_PRODUCT_IDX		1
#define STRING_DESCRIPTION_IDX		2

static char manufacturer[50];

static struct usb_string strings_dev[] = {
	[STRING_MANUFACTURER_IDX].s = manufacturer,
	[STRING_PRODUCT_IDX].s = GS_VERSION_NAME,
	[STRING_DESCRIPTION_IDX].s = NULL /* updated; f(use_acm) */,
	{  } /* 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 usb_device_descriptor device_desc = {
	.bLength =		USB_DT_DEVICE_SIZE,
	.bDescriptorType =	USB_DT_DEVICE,
	.bcdUSB =		__constant_cpu_to_le16(0x0200),
	/* .bDeviceClass = f(use_acm) */
	.bDeviceSubClass =	0,
	.bDeviceProtocol =	0,
	/* .bMaxPacketSize0 = f(hardware) */
	.idVendor =		__constant_cpu_to_le16(GS_VENDOR_ID),
	/* .idProduct =	f(use_acm) */
	/* .bcdDevice = f(hardware) */
	/* .iManufacturer = DYNAMIC */
	/* .iProduct = DYNAMIC */
	.bNumConfigurations =	1,
};

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,
};

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

/* Module */
MODULE_DESCRIPTION(GS_VERSION_NAME);
MODULE_AUTHOR("Al Borchers");
MODULE_AUTHOR("David Brownell");
MODULE_LICENSE("GPL");

static int use_acm = true;
module_param(use_acm, bool, 0);
MODULE_PARM_DESC(use_acm, "Use CDC ACM, default=yes");

static unsigned n_ports = 1;
module_param(n_ports, uint, 0);
MODULE_PARM_DESC(n_ports, "number of ports to create, default=1");

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

static int __init serial_bind_config(struct usb_configuration *c)
{
	unsigned i;
	int status = 0;

	for (i = 0; i < n_ports && status == 0; i++) {
		if (use_acm)
			status = acm_bind_config(c, i);
		else
			status = gser_bind_config(c, i);
	}
	return status;
}

static struct usb_configuration serial_config_driver = {
	/* .label = f(use_acm) */
	.bind		= serial_bind_config,
	/* .bConfigurationValue = f(use_acm) */
	/* .iConfiguration = DYNAMIC */
	.bmAttributes	= USB_CONFIG_ATT_SELFPOWER,
	.bMaxPower	= 1,	/* 2 mA, minimal */
};

static int __init gs_bind(struct usb_composite_dev *cdev)
{
	int			gcnum;
	struct usb_gadget	*gadget = cdev->gadget;
	int			status;

	status = gserial_setup(cdev->gadget, n_ports);
	if (status < 0)
		return status;

	/* Allocate string descriptor numbers ... note that string
	 * contents can be overridden by the composite_dev glue.
	 */

	/* device description: manufacturer, product */
	snprintf(manufacturer, sizeof manufacturer, "%s %s with %s",
		init_utsname()->sysname, init_utsname()->release,
		gadget->name);
	status = usb_string_id(cdev);
	if (status < 0)
		goto fail;
	strings_dev[STRING_MANUFACTURER_IDX].id = status;

	device_desc.iManufacturer = status;

	status = usb_string_id(cdev);
	if (status < 0)
		goto fail;
	strings_dev[STRING_PRODUCT_IDX].id = status;

	device_desc.iProduct = status;

	/* config description */
	status = usb_string_id(cdev);
	if (status < 0)
		goto fail;
	strings_dev[STRING_DESCRIPTION_IDX].id = status;

	serial_config_driver.iConfiguration = status;

	/* set up other descriptors */
	gcnum = usb_gadget_controller_number(gadget);
	if (gcnum >= 0)
		device_desc.bcdDevice = cpu_to_le16(GS_VERSION_NUM | gcnum);
	else {
		/* this 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.
		 */
		pr_warning("gs_bind: controller '%s' not recognized\n",
			gadget->name);
		device_desc.bcdDevice =
			__constant_cpu_to_le16(GS_VERSION_NUM | 0x0099);
	}

	if (gadget_is_otg(cdev->gadget)) {
		serial_config_driver.descriptors = otg_desc;
		serial_config_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
	}

	/* register our configuration */
	status = usb_add_config(cdev, &serial_config_driver);
	if (status < 0)
		goto fail;

	INFO(cdev, "%s\n", GS_VERSION_NAME);

	return 0;

fail:
	gserial_cleanup();
	return status;
}

static struct usb_composite_driver gserial_driver = {
	.name		= "g_serial",
	.dev		= &device_desc,
	.strings	= dev_strings,
	.bind		= gs_bind,
};

static int __init init(void)
{
	/* We *could* export two configs; that'd be much cleaner...
	 * but neither of these product IDs was defined that way.
	 */
	if (use_acm) {
		serial_config_driver.label = "CDC ACM config";
		serial_config_driver.bConfigurationValue = 2;
		device_desc.bDeviceClass = USB_CLASS_COMM;
		device_desc.idProduct =
				__constant_cpu_to_le16(GS_CDC_PRODUCT_ID);
	} else {
		serial_config_driver.label = "Generic Serial config";
		serial_config_driver.bConfigurationValue = 1;
		device_desc.bDeviceClass = USB_CLASS_VENDOR_SPEC;
		device_desc.idProduct =
				__constant_cpu_to_le16(GS_PRODUCT_ID);
	}
	strings_dev[STRING_DESCRIPTION_IDX].s = serial_config_driver.label;

	return usb_composite_register(&gserial_driver);
}
module_init(init);

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