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-rw-r--r--drivers/char/tipar.c564
1 files changed, 564 insertions, 0 deletions
diff --git a/drivers/char/tipar.c b/drivers/char/tipar.c
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+/* Hey EMACS -*- linux-c -*-
+ *
+ * tipar - low level driver for handling a parallel link cable designed
+ * for Texas Instruments graphing calculators (http://lpg.ticalc.org).
+ * A part of the TiLP project.
+ *
+ * Copyright (C) 2000-2002, Romain Lievin <roms@lpg.ticalc.org>
+ * under the terms of the GNU General Public License.
+ *
+ * Various fixes & clean-up from the Linux Kernel Mailing List
+ * (Alan Cox, Richard B. Johnson, Christoph Hellwig).
+ */
+
+/* This driver should, in theory, work with any parallel port that has an
+ * appropriate low-level driver; all I/O is done through the parport
+ * abstraction layer.
+ *
+ * If this driver is built into the kernel, you can configure it using the
+ * kernel command-line. For example:
+ *
+ * tipar=timeout,delay (set timeout and delay)
+ *
+ * If the driver is loaded as a module, similar functionality is available
+ * using module parameters. The equivalent of the above commands would be:
+ *
+ * # insmod tipar timeout=15 delay=10
+ */
+
+/* COMPATIBILITY WITH OLD KERNELS
+ *
+ * Usually, parallel cables were bound to ports at
+ * particular I/O addresses, as follows:
+ *
+ * tipar0 0x378
+ * tipar1 0x278
+ * tipar2 0x3bc
+ *
+ *
+ * This driver, by default, binds tipar devices according to parport and
+ * the minor number.
+ *
+ */
+#undef DEBUG /* change to #define to get debugging
+ * output - for pr_debug() */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/fcntl.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <asm/uaccess.h>
+#include <linux/ioport.h>
+#include <asm/io.h>
+#include <linux/bitops.h>
+#include <linux/devfs_fs_kernel.h> /* DevFs support */
+#include <linux/parport.h> /* Our code depend on parport */
+#include <linux/device.h>
+
+/*
+ * TI definitions
+ */
+#include <linux/ticable.h>
+
+/*
+ * Version Information
+ */
+#define DRIVER_VERSION "1.19"
+#define DRIVER_AUTHOR "Romain Lievin <roms@lpg.ticalc.org>"
+#define DRIVER_DESC "Device driver for TI/PC parallel link cables"
+#define DRIVER_LICENSE "GPL"
+
+#define VERSION(ver,rel,seq) (((ver)<<16) | ((rel)<<8) | (seq))
+
+/* ----- global variables --------------------------------------------- */
+
+struct tipar_struct {
+ struct pardevice *dev; /* Parport device entry */
+};
+
+#define PP_NO 3
+static struct tipar_struct table[PP_NO];
+
+static int delay = IO_DELAY; /* inter-bit delay in microseconds */
+static int timeout = TIMAXTIME; /* timeout in tenth of seconds */
+
+static unsigned int tp_count; /* tipar count */
+static unsigned long opened; /* opened devices */
+
+static struct class_simple *tipar_class;
+
+/* --- macros for parport access -------------------------------------- */
+
+#define r_dtr(x) (parport_read_data(table[(x)].dev->port))
+#define r_str(x) (parport_read_status(table[(x)].dev->port))
+#define w_ctr(x,y) (parport_write_control(table[(x)].dev->port, (y)))
+#define w_dtr(x,y) (parport_write_data(table[(x)].dev->port, (y)))
+
+/* --- setting states on the D-bus with the right timing: ------------- */
+
+static inline void
+outbyte(int value, int minor)
+{
+ w_dtr(minor, value);
+}
+
+static inline int
+inbyte(int minor)
+{
+ return (r_str(minor));
+}
+
+static inline void
+init_ti_parallel(int minor)
+{
+ outbyte(3, minor);
+}
+
+/* ----- global defines ----------------------------------------------- */
+
+#define START(x) { x = jiffies + (HZ * timeout) / 10; }
+#define WAIT(x) { \
+ if (time_before((x), jiffies)) return -1; \
+ if (need_resched()) schedule(); }
+
+/* ----- D-bus bit-banging functions ---------------------------------- */
+
+/* D-bus protocol (45kbit/s max):
+ 1 0 0
+ _______ ______|______ __________|________ __________
+Red : ________ | ____ | ____
+ _ ____________|________ ______|__________ _____
+White: ________ | ______ | _______
+*/
+
+/* Try to transmit a byte on the specified port (-1 if error). */
+static int
+put_ti_parallel(int minor, unsigned char data)
+{
+ unsigned int bit;
+ unsigned long max;
+
+ for (bit = 0; bit < 8; bit++) {
+ if (data & 1) {
+ outbyte(2, minor);
+ START(max);
+ do {
+ WAIT(max);
+ } while (inbyte(minor) & 0x10);
+
+ outbyte(3, minor);
+ START(max);
+ do {
+ WAIT(max);
+ } while (!(inbyte(minor) & 0x10));
+ } else {
+ outbyte(1, minor);
+ START(max);
+ do {
+ WAIT(max);
+ } while (inbyte(minor) & 0x20);
+
+ outbyte(3, minor);
+ START(max);
+ do {
+ WAIT(max);
+ } while (!(inbyte(minor) & 0x20));
+ }
+
+ data >>= 1;
+ udelay(delay);
+
+ if (need_resched())
+ schedule();
+ }
+
+ return 0;
+}
+
+/* Receive a byte on the specified port or -1 if error. */
+static int
+get_ti_parallel(int minor)
+{
+ unsigned int bit;
+ unsigned char v, data = 0;
+ unsigned long max;
+
+ for (bit = 0; bit < 8; bit++) {
+ START(max);
+ do {
+ WAIT(max);
+ } while ((v = inbyte(minor) & 0x30) == 0x30);
+
+ if (v == 0x10) {
+ data = (data >> 1) | 0x80;
+ outbyte(1, minor);
+ START(max);
+ do {
+ WAIT(max);
+ } while (!(inbyte(minor) & 0x20));
+ outbyte(3, minor);
+ } else {
+ data = data >> 1;
+ outbyte(2, minor);
+ START(max);
+ do {
+ WAIT(max);
+ } while (!(inbyte(minor) & 0x10));
+ outbyte(3, minor);
+ }
+
+ udelay(delay);
+ if (need_resched())
+ schedule();
+ }
+
+ return (int) data;
+}
+
+/* Try to detect a parallel link cable on the specified port */
+static int
+probe_ti_parallel(int minor)
+{
+ int i;
+ int seq[] = { 0x00, 0x20, 0x10, 0x30 };
+
+ for (i = 3; i >= 0; i--) {
+ outbyte(3, minor);
+ outbyte(i, minor);
+ udelay(delay);
+ pr_debug("tipar: Probing -> %i: 0x%02x 0x%02x\n", i,
+ data & 0x30, seq[i]);
+ if ((inbyte(minor) & 0x30) != seq[i]) {
+ outbyte(3, minor);
+ return -1;
+ }
+ }
+
+ outbyte(3, minor);
+ return 0;
+}
+
+/* ----- kernel module functions--------------------------------------- */
+
+static int
+tipar_open(struct inode *inode, struct file *file)
+{
+ unsigned int minor = iminor(inode) - TIPAR_MINOR;
+
+ if (minor > tp_count - 1)
+ return -ENXIO;
+
+ if (test_and_set_bit(minor, &opened))
+ return -EBUSY;
+
+ parport_claim_or_block(table[minor].dev);
+ init_ti_parallel(minor);
+ parport_release(table[minor].dev);
+
+ return nonseekable_open(inode, file);
+}
+
+static int
+tipar_close(struct inode *inode, struct file *file)
+{
+ unsigned int minor = iminor(inode) - TIPAR_MINOR;
+
+ if (minor > tp_count - 1)
+ return -ENXIO;
+
+ clear_bit(minor, &opened);
+
+ return 0;
+}
+
+static ssize_t
+tipar_write (struct file *file, const char __user *buf, size_t count,
+ loff_t * ppos)
+{
+ unsigned int minor = iminor(file->f_dentry->d_inode) - TIPAR_MINOR;
+ ssize_t n;
+
+ parport_claim_or_block(table[minor].dev);
+
+ for (n = 0; n < count; n++) {
+ unsigned char b;
+
+ if (get_user(b, buf + n)) {
+ n = -EFAULT;
+ goto out;
+ }
+
+ if (put_ti_parallel(minor, b) == -1) {
+ init_ti_parallel(minor);
+ n = -ETIMEDOUT;
+ goto out;
+ }
+ }
+ out:
+ parport_release(table[minor].dev);
+ return n;
+}
+
+static ssize_t
+tipar_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
+{
+ int b = 0;
+ unsigned int minor = iminor(file->f_dentry->d_inode) - TIPAR_MINOR;
+ ssize_t retval = 0;
+ ssize_t n = 0;
+
+ if (count == 0)
+ return 0;
+
+ parport_claim_or_block(table[minor].dev);
+
+ while (n < count) {
+ b = get_ti_parallel(minor);
+ if (b == -1) {
+ init_ti_parallel(minor);
+ retval = -ETIMEDOUT;
+ goto out;
+ } else {
+ if (put_user(b, buf + n)) {
+ retval = -EFAULT;
+ break;
+ } else
+ retval = ++n;
+ }
+
+ /* Non-blocking mode : try again ! */
+ if (file->f_flags & O_NONBLOCK) {
+ retval = -EAGAIN;
+ goto out;
+ }
+
+ /* Signal pending, try again ! */
+ if (signal_pending(current)) {
+ retval = -ERESTARTSYS;
+ goto out;
+ }
+
+ if (need_resched())
+ schedule();
+ }
+
+ out:
+ parport_release(table[minor].dev);
+ return retval;
+}
+
+static int
+tipar_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ int retval = 0;
+
+ switch (cmd) {
+ case IOCTL_TIPAR_DELAY:
+ delay = (int)arg; //get_user(delay, &arg);
+ break;
+ case IOCTL_TIPAR_TIMEOUT:
+ if (arg != 0)
+ timeout = (int)arg;
+ else
+ retval = -EINVAL;
+ break;
+ default:
+ retval = -ENOTTY;
+ break;
+ }
+
+ return retval;
+}
+
+/* ----- kernel module registering ------------------------------------ */
+
+static struct file_operations tipar_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .read = tipar_read,
+ .write = tipar_write,
+ .ioctl = tipar_ioctl,
+ .open = tipar_open,
+ .release = tipar_close,
+};
+
+/* --- initialisation code ------------------------------------- */
+
+#ifndef MODULE
+/* You must set these - there is no sane way to probe for this cable.
+ * You can use 'tipar=timeout,delay' to set these now. */
+static int __init
+tipar_setup(char *str)
+{
+ int ints[2];
+
+ str = get_options(str, ARRAY_SIZE(ints), ints);
+
+ if (ints[0] > 0) {
+ if (ints[1] != 0)
+ timeout = ints[1];
+ else
+ printk(KERN_WARNING "tipar: bad timeout value (0), "
+ "using default value instead");
+ if (ints[0] > 1) {
+ delay = ints[2];
+ }
+ }
+
+ return 1;
+}
+#endif
+
+/*
+ * Register our module into parport.
+ * Pass also 2 callbacks functions to parport: a pre-emptive function and an
+ * interrupt handler function (unused).
+ * Display a message such "tipar0: using parport0 (polling)".
+ */
+static int
+tipar_register(int nr, struct parport *port)
+{
+ int err = 0;
+
+ /* Register our module into parport */
+ table[nr].dev = parport_register_device(port, "tipar",
+ NULL, NULL, NULL, 0,
+ (void *) &table[nr]);
+
+ if (table[nr].dev == NULL) {
+ err = 1;
+ goto out;
+ }
+
+ class_simple_device_add(tipar_class, MKDEV(TIPAR_MAJOR,
+ TIPAR_MINOR + nr), NULL, "par%d", nr);
+ /* Use devfs, tree: /dev/ticables/par/[0..2] */
+ err = devfs_mk_cdev(MKDEV(TIPAR_MAJOR, TIPAR_MINOR + nr),
+ S_IFCHR | S_IRUGO | S_IWUGO,
+ "ticables/par/%d", nr);
+ if (err)
+ goto out_class;
+
+ /* Display informations */
+ pr_info("tipar%d: using %s (%s)\n", nr, port->name, (port->irq ==
+ PARPORT_IRQ_NONE) ? "polling" : "interrupt-driven");
+
+ if (probe_ti_parallel(nr) != -1)
+ pr_info("tipar%d: link cable found\n", nr);
+ else
+ pr_info("tipar%d: link cable not found\n", nr);
+
+ err = 0;
+ goto out;
+
+out_class:
+ class_simple_device_remove(MKDEV(TIPAR_MAJOR, TIPAR_MINOR + nr));
+ class_simple_destroy(tipar_class);
+out:
+ return err;
+}
+
+static void
+tipar_attach(struct parport *port)
+{
+ if (tp_count == PP_NO) {
+ pr_info("tipar: ignoring parallel port (max. %d)\n", PP_NO);
+ return;
+ }
+
+ if (!tipar_register(tp_count, port))
+ tp_count++;
+}
+
+static void
+tipar_detach(struct parport *port)
+{
+ /* Nothing to do */
+}
+
+static struct parport_driver tipar_driver = {
+ .name = "tipar",
+ .attach = tipar_attach,
+ .detach = tipar_detach,
+};
+
+static int __init
+tipar_init_module(void)
+{
+ int err = 0;
+
+ pr_info("tipar: parallel link cable driver, version %s\n",
+ DRIVER_VERSION);
+
+ if (register_chrdev(TIPAR_MAJOR, "tipar", &tipar_fops)) {
+ printk(KERN_ERR "tipar: unable to get major %d\n", TIPAR_MAJOR);
+ err = -EIO;
+ goto out;
+ }
+
+ /* Use devfs with tree: /dev/ticables/par/[0..2] */
+ devfs_mk_dir("ticables/par");
+
+ tipar_class = class_simple_create(THIS_MODULE, "ticables");
+ if (IS_ERR(tipar_class)) {
+ err = PTR_ERR(tipar_class);
+ goto out_chrdev;
+ }
+ if (parport_register_driver(&tipar_driver)) {
+ printk(KERN_ERR "tipar: unable to register with parport\n");
+ err = -EIO;
+ goto out;
+ }
+
+ err = 0;
+ goto out;
+
+out_chrdev:
+ unregister_chrdev(TIPAR_MAJOR, "tipar");
+out:
+ return err;
+}
+
+static void __exit
+tipar_cleanup_module(void)
+{
+ unsigned int i;
+
+ /* Unregistering module */
+ parport_unregister_driver(&tipar_driver);
+
+ unregister_chrdev(TIPAR_MAJOR, "tipar");
+
+ for (i = 0; i < PP_NO; i++) {
+ if (table[i].dev == NULL)
+ continue;
+ parport_unregister_device(table[i].dev);
+ class_simple_device_remove(MKDEV(TIPAR_MAJOR, i));
+ devfs_remove("ticables/par/%d", i);
+ }
+ class_simple_destroy(tipar_class);
+ devfs_remove("ticables/par");
+
+ pr_info("tipar: module unloaded\n");
+}
+
+/* --------------------------------------------------------------------- */
+
+__setup("tipar=", tipar_setup);
+module_init(tipar_init_module);
+module_exit(tipar_cleanup_module);
+
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE(DRIVER_LICENSE);
+
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Timeout (default=1.5 seconds)");
+module_param(delay, int, 0);
+MODULE_PARM_DESC(delay, "Inter-bit delay (default=10 microseconds)");
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.