linux/drivers/char/ppdev.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * linux/drivers/char/ppdev.c
 *
 * This is the code behind /dev/parport* -- it allows a user-space
 * application to use the parport subsystem.
 *
 * Copyright (C) 1998-2000, 2002 Tim Waugh <[email protected]>
 *
 * A /dev/parportx device node represents an arbitrary device
 * on port 'x'.  The following operations are possible:
 *
 * open		do nothing, set up default IEEE 1284 protocol to be COMPAT
 * close	release port and unregister device (if necessary)
 * ioctl
 *   EXCL	register device exclusively (may fail)
 *   CLAIM	(register device first time) parport_claim_or_block
 *   RELEASE	parport_release
 *   SETMODE	set the IEEE 1284 protocol to use for read/write
 *   SETPHASE	set the IEEE 1284 phase of a particular mode.  Not to be
 *              confused with ioctl(fd, SETPHASER, &stun). ;-)
 *   DATADIR	data_forward / data_reverse
 *   WDATA	write_data
 *   RDATA	read_data
 *   WCONTROL	write_control
 *   RCONTROL	read_control
 *   FCONTROL	frob_control
 *   RSTATUS	read_status
 *   NEGOT	parport_negotiate
 *   YIELD	parport_yield_blocking
 *   WCTLONIRQ	on interrupt, set control lines
 *   CLRIRQ	clear (and return) interrupt count
 *   SETTIME	sets device timeout (struct timeval)
 *   GETTIME	gets device timeout (struct timeval)
 *   GETMODES	gets hardware supported modes (unsigned int)
 *   GETMODE	gets the current IEEE1284 mode
 *   GETPHASE   gets the current IEEE1284 phase
 *   GETFLAGS   gets current (user-visible) flags
 *   SETFLAGS   sets current (user-visible) flags
 * read/write	read or write in current IEEE 1284 protocol
 * select	wait for interrupt (in readfds)
 *
 * Changes:
 * Added SETTIME/GETTIME ioctl, Fred Barnes, 1999.
 *
 * Arnaldo Carvalho de Melo <[email protected]> 2000/08/25
 * - On error, copy_from_user and copy_to_user do not return -EFAULT,
 *   They return the positive number of bytes *not* copied due to address
 *   space errors.
 *
 * Added GETMODES/GETMODE/GETPHASE ioctls, Fred Barnes <[email protected]>, 03/01/2001.
 * Added GETFLAGS/SETFLAGS ioctls, Fred Barnes, 04/2001
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched/signal.h>
#include <linux/device.h>
#include <linux/ioctl.h>
#include <linux/parport.h>
#include <linux/ctype.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/major.h>
#include <linux/ppdev.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>
#include <linux/compat.h>

#define PP_VERSION …
#define CHRDEV …

struct pp_struct { … };

/* should we use PARDEVICE_MAX here? */
static struct device *devices[PARPORT_MAX];

static DEFINE_IDA(ida_index);

/* pp_struct.flags bitfields */
#define PP_CLAIMED …
#define PP_EXCL …

/* Other constants */
#define PP_INTERRUPT_TIMEOUT …
#define PP_BUFFER_SIZE …
#define PARDEVICE_MAX …

static DEFINE_MUTEX(pp_do_mutex);

/* define fixed sized ioctl cmd for y2038 migration */
#define PPGETTIME32 …
#define PPSETTIME32 …
#define PPGETTIME64 …
#define PPSETTIME64 …

static inline void pp_enable_irq(struct pp_struct *pp)
{ … }

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

static ssize_t pp_write(struct file *file, const char __user *buf,
			size_t count, loff_t *ppos)
{ … }

static void pp_irq(void *private)
{ … }

static int register_device(int minor, struct pp_struct *pp)
{ … }

static enum ieee1284_phase init_phase(int mode)
{ … }

static int pp_set_timeout(struct pardevice *pdev, long tv_sec, int tv_usec)
{ … }

static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{ … }

static long pp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{ … }

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

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

/* No kernel lock held - fine */
static __poll_t pp_poll(struct file *file, poll_table *wait)
{ … }

static const struct class ppdev_class = …;

static const struct file_operations pp_fops = …;

static void pp_attach(struct parport *port)
{ … }

static void pp_detach(struct parport *port)
{ … }

static int pp_probe(struct pardevice *par_dev)
{ … }

static struct parport_driver pp_driver = …;

static int __init ppdev_init(void)
{ … }

static void __exit ppdev_cleanup(void)
{ … }

module_init(…) …;
module_exit(ppdev_cleanup);

MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;
MODULE_ALIAS_CHARDEV_MAJOR(…);