drivers/usb/gadget/legacy/printer.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * printer.c -- Printer gadget driver
 *
 * Copyright (C) 2003-2005 David Brownell
 * Copyright (C) 2006 Craig W. Nadler
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <asm/byteorder.h>

#include <linux/usb/ch9.h>
#include <linux/usb/composite.h>
#include <linux/usb/gadget.h>
#include <linux/usb/g_printer.h>

USB_GADGET_COMPOSITE_OPTIONS();

#define DRIVER_DESC		"Printer Gadget"
#define DRIVER_VERSION		"2015 FEB 17"

static const char shortname [] = "printer";

#include "u_printer.h"

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

/* DO NOT REUSE THESE IDs with a protocol-incompatible driver!!  Ever!!
 * Instead:  allocate your own, using normal USB-IF procedures.
 */

/* Thanks to NetChip Technologies for donating this product ID.
 */
#define PRINTER_VENDOR_NUM	0x0525		/* NetChip */
#define PRINTER_PRODUCT_NUM	0xa4a8		/* Linux-USB Printer Gadget */

/* Some systems will want different product identifiers published in the
 * device descriptor, either numbers or strings or both.  These string
 * parameters are in UTF-8 (superset of ASCII's 7 bit characters).
 */

module_param_named(iSerialNum, coverwrite.serial_number, charp, S_IRUGO);
MODULE_PARM_DESC(iSerialNum, "1");

static char *iPNPstring;
module_param(iPNPstring, charp, S_IRUGO);
MODULE_PARM_DESC(iPNPstring, "MFG:linux;MDL:g_printer;CLS:PRINTER;SN:1;");

/* Number of requests to allocate per endpoint, not used for ep0. */
static unsigned qlen = 10;
module_param(qlen, uint, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(qlen, "The number of 8k buffers to use per endpoint");

#define QLEN	qlen

static struct usb_function_instance *fi_printer;
static struct usb_function *f_printer;

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

/*
 * DESCRIPTORS ... most are static, but strings and (full) configuration
 * descriptors are built on demand.
 */

static struct usb_device_descriptor device_desc = {
	.bLength =		sizeof device_desc,
	.bDescriptorType =	USB_DT_DEVICE,
	/* .bcdUSB = DYNAMIC */
	.bDeviceClass =		USB_CLASS_PER_INTERFACE,
	.bDeviceSubClass =	0,
	.bDeviceProtocol =	0,
	.idVendor =		cpu_to_le16(PRINTER_VENDOR_NUM),
	.idProduct =		cpu_to_le16(PRINTER_PRODUCT_NUM),
	.bNumConfigurations =	1
};

static const struct usb_descriptor_header *otg_desc[2];

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

/* descriptors that are built on-demand */

static char				product_desc [40] = DRIVER_DESC;
static char				serial_num [40] = "1";
static char				*pnp_string =
	"MFG:linux;MDL:g_printer;CLS:PRINTER;SN:1;";

/* static strings, in UTF-8 */
static struct usb_string		strings [] = {
	[USB_GADGET_MANUFACTURER_IDX].s = "",
	[USB_GADGET_PRODUCT_IDX].s = product_desc,
	[USB_GADGET_SERIAL_IDX].s =	serial_num,
	{  }		/* end of list */
};

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

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

static struct usb_configuration printer_cfg_driver = {
	.label			= "printer",
	.bConfigurationValue	= 1,
	.bmAttributes		= USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
};

static int printer_do_config(struct usb_configuration *c)
{
	struct usb_gadget	*gadget = c->cdev->gadget;
	int			status = 0;

	usb_ep_autoconfig_reset(gadget);

	usb_gadget_set_selfpowered(gadget);

	if (gadget_is_otg(gadget)) {
		printer_cfg_driver.descriptors = otg_desc;
		printer_cfg_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP;
	}

	f_printer = usb_get_function(fi_printer);
	if (IS_ERR(f_printer))
		return PTR_ERR(f_printer);

	status = usb_add_function(c, f_printer);
	if (status < 0)
		usb_put_function(f_printer);

	return status;
}

static int printer_bind(struct usb_composite_dev *cdev)
{
	struct f_printer_opts *opts;
	int ret;

	fi_printer = usb_get_function_instance("printer");
	if (IS_ERR(fi_printer))
		return PTR_ERR(fi_printer);

	opts = container_of(fi_printer, struct f_printer_opts, func_inst);
	opts->minor = 0;
	opts->q_len = QLEN;
	if (iPNPstring) {
		opts->pnp_string = kstrdup(iPNPstring, GFP_KERNEL);
		if (!opts->pnp_string) {
			ret = -ENOMEM;
			goto fail_put_func_inst;
		}
		opts->pnp_string_allocated = true;
		/*
		 * we don't free this memory in case of error
		 * as printer cleanup func will do this for us
		 */
	} else {
		opts->pnp_string = pnp_string;
	}

	ret = usb_string_ids_tab(cdev, strings);
	if (ret < 0)
		goto fail_put_func_inst;

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

	if (gadget_is_otg(cdev->gadget) && !otg_desc[0]) {
		struct usb_descriptor_header *usb_desc;

		usb_desc = usb_otg_descriptor_alloc(cdev->gadget);
		if (!usb_desc) {
			ret = -ENOMEM;
			goto fail_put_func_inst;
		}
		usb_otg_descriptor_init(cdev->gadget, usb_desc);
		otg_desc[0] = usb_desc;
		otg_desc[1] = NULL;
	}

	ret = usb_add_config(cdev, &printer_cfg_driver, printer_do_config);
	if (ret)
		goto fail_free_otg_desc;

	usb_composite_overwrite_options(cdev, &coverwrite);
	return ret;

fail_free_otg_desc:
	kfree(otg_desc[0]);
	otg_desc[0] = NULL;
fail_put_func_inst:
	usb_put_function_instance(fi_printer);
	return ret;
}

static int printer_unbind(struct usb_composite_dev *cdev)
{
	usb_put_function(f_printer);
	usb_put_function_instance(fi_printer);

	kfree(otg_desc[0]);
	otg_desc[0] = NULL;

	return 0;
}

static struct usb_composite_driver printer_driver = {
	.name           = shortname,
	.dev            = &device_desc,
	.strings        = dev_strings,
	.max_speed      = USB_SPEED_SUPER,
	.bind		= printer_bind,
	.unbind		= printer_unbind,
};

module_usb_composite_driver(printer_driver);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR("Craig Nadler");
MODULE_LICENSE("GPL");