linux/drivers/usb/misc/chaoskey.c

// SPDX-License-Identifier: GPL-2.0
/*
 * chaoskey - driver for ChaosKey device from Altus Metrum.
 *
 * This device provides true random numbers using a noise source based
 * on a reverse-biased p-n junction in avalanche breakdown. More
 * details can be found at http://chaoskey.org
 *
 * The driver connects to the kernel hardware RNG interface to provide
 * entropy for /dev/random and other kernel activities. It also offers
 * a separate /dev/ entry to allow for direct access to the random
 * bit stream.
 *
 * Copyright © 2015 Keith Packard <[email protected]>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/wait.h>
#include <linux/hw_random.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>

static struct usb_driver chaoskey_driver;
static struct usb_class_driver chaoskey_class;
static int chaoskey_rng_read(struct hwrng *rng, void *data,
			     size_t max, bool wait);

#define usb_dbg(usb_if, format, arg...) …

#define usb_err(usb_if, format, arg...) …

/* Version Information */
#define DRIVER_AUTHOR …
#define DRIVER_DESC …
#define DRIVER_SHORT …

MODULE_AUTHOR(…);
MODULE_DESCRIPTION(…);
MODULE_LICENSE(…) …;

#define CHAOSKEY_VENDOR_ID …
#define CHAOSKEY_PRODUCT_ID …

#define ALEA_VENDOR_ID …
#define ALEA_PRODUCT_ID …

#define CHAOSKEY_BUF_LEN …

#define NAK_TIMEOUT …
#define ALEA_FIRST_TIMEOUT …

#ifdef CONFIG_USB_DYNAMIC_MINORS
#define USB_CHAOSKEY_MINOR_BASE …
#else

/* IOWARRIOR_MINOR_BASE + 16, not official yet */
#define USB_CHAOSKEY_MINOR_BASE …
#endif

static const struct usb_device_id chaoskey_table[] = …;
MODULE_DEVICE_TABLE(usb, chaoskey_table);

static void chaos_read_callback(struct urb *urb);

/* Driver-local specific stuff */
struct chaoskey { … };

static void chaoskey_free(struct chaoskey *dev)
{ … }

static int chaoskey_probe(struct usb_interface *interface,
			  const struct usb_device_id *id)
{ … }

static void chaoskey_disconnect(struct usb_interface *interface)
{ … }

static int chaoskey_open(struct inode *inode, struct file *file)
{ … }

static int chaoskey_release(struct inode *inode, struct file *file)
{ … }

static void chaos_read_callback(struct urb *urb)
{ … }

/* Fill the buffer. Called with dev->lock held
 */
static int _chaoskey_fill(struct chaoskey *dev)
{ … }

static ssize_t chaoskey_read(struct file *file,
			     char __user *buffer,
			     size_t count,
			     loff_t *ppos)
{ … }

static int chaoskey_rng_read(struct hwrng *rng, void *data,
			     size_t max, bool wait)
{ … }

#ifdef CONFIG_PM
static int chaoskey_suspend(struct usb_interface *interface,
			    pm_message_t message)
{ … }

static int chaoskey_resume(struct usb_interface *interface)
{ … }
#else
#define chaoskey_suspend …
#define chaoskey_resume …
#endif

/* file operation pointers */
static const struct file_operations chaoskey_fops = …;

/* class driver information */
static struct usb_class_driver chaoskey_class = …;

/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver chaoskey_driver = …;

module_usb_driver(…) …;