/* Hey EMACS -*- linux-c -*-
 *
 * tiglusb -- Texas Instruments' USB GraphLink (aka SilverLink) driver.
 * Target: Texas Instruments graphing calculators (http://lpg.ticalc.org).
 *      
 * Copyright (C) 2001-2002: 
 *   Romain Lievin <roms@lpg.ticalc.org>
 *   Julien BLACHE <jb@technologeek.org>
 * under the terms of the GNU General Public License.
 *
 * Based on dabusb.c, printer.c & scanner.c
 *
 * Please see the file: linux/Documentation/usb/SilverLink.txt 
 * and the website at:  http://lpg.ticalc.org/prj_usb/
 * for more info.
 *
 */

#include <linux/module.h>
#include <linux/socket.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <linux/delay.h>
#include <linux/usb.h>
#include <linux/smp_lock.h>
#include <linux/devfs_fs_kernel.h>

#include <linux/ticable.h>
#include "tiglusb.h"

/*
 * Version Information
 */
#define DRIVER_VERSION "1.03"
#define DRIVER_AUTHOR  "Romain Lievin <roms@lpg.ticalc.org> & Julien Blache <jb@jblache.org>"
#define DRIVER_DESC    "TI-GRAPH LINK USB (aka SilverLink) driver"
#define DRIVER_LICENSE "GPL"


/* ----- global variables --------------------------------------------- */

static tiglusb_t tiglusb[MAXTIGL];
static int timeout = TIMAXTIME;	/* timeout in tenth of seconds     */

static devfs_handle_t devfs_handle;

/*---------- misc functions ------------------------------------------- */

/* Unregister device */
static void usblp_cleanup (tiglusb_t * s)
{
	devfs_unregister (s->devfs);
	//memset(tiglusb[s->minor], 0, sizeof(tiglusb_t));
	info ("tiglusb%d removed", s->minor);
}

/* Re-initialize device */
static int clear_device (struct usb_device *dev)
{
	if (usb_set_configuration (dev, dev->config[0].bConfigurationValue) < 0) {
		printk ("tiglusb: clear_device failed\n");
		return -1;
	}

	return 0;
}

/* Clear input & output pipes (endpoints) */
static int clear_pipes (struct usb_device *dev)
{
	unsigned int pipe;

	pipe = usb_sndbulkpipe (dev, 1);
	if (usb_clear_halt (dev, usb_pipeendpoint (pipe))) {
		printk ("tiglusb: clear_pipe (r), request failed\n");
		return -1;
	}

	pipe = usb_sndbulkpipe (dev, 2);
	if (usb_clear_halt (dev, usb_pipeendpoint (pipe))) {
		printk ("tiglusb: clear_pipe (w), request failed\n");
		return -1;
	}

	return 0;
}

/* ----- kernel module functions--------------------------------------- */

static int tiglusb_open (struct inode *inode, struct file *file)
{
	int devnum = minor (inode->i_rdev);
	ptiglusb_t s;

	if (devnum < TIUSB_MINOR || devnum >= (TIUSB_MINOR + MAXTIGL))
		return -EIO;

	s = &tiglusb[devnum - TIUSB_MINOR];

	down (&s->mutex);

	while (!s->dev || s->opened) {
		up (&s->mutex);

		if (file->f_flags & O_NONBLOCK) {
			return -EBUSY;
		}
		schedule_timeout (HZ / 2);

		if (signal_pending (current)) {
			return -EAGAIN;
		}
		down (&s->mutex);
	}

	s->opened = 1;
	up (&s->mutex);

	file->f_pos = 0;
	file->private_data = s;

	return 0;
}

static int tiglusb_release (struct inode *inode, struct file *file)
{
	ptiglusb_t s = (ptiglusb_t) file->private_data;

	lock_kernel ();
	down (&s->mutex);
	s->state = _stopped;
	up (&s->mutex);

	if (!s->remove_pending)
		clear_device (s->dev);
	else
		wake_up (&s->remove_ok);

	s->opened = 0;
	unlock_kernel ();

	return 0;
}

static ssize_t tiglusb_read (struct file *file, char *buf, size_t count, loff_t * ppos)
{
	ptiglusb_t s = (ptiglusb_t) file->private_data;
	ssize_t ret = 0;
	int bytes_to_read = 0;
	int bytes_read = 0;
	int result = 0;
	char buffer[BULK_RCV_MAX];
	unsigned int pipe;

	if (*ppos)
		return -ESPIPE;

	if (s->remove_pending)
		return -EIO;

	if (!s->dev)
		return -EIO;

	bytes_to_read = (count >= BULK_RCV_MAX) ? BULK_RCV_MAX : count;

	pipe = usb_rcvbulkpipe (s->dev, 1);
	result = usb_bulk_msg (s->dev, pipe, buffer, bytes_to_read,
			       &bytes_read, HZ / (timeout / 10));
	if (result == -ETIMEDOUT) {	/* NAK */
		ret = result;
		if (!bytes_read) {
			printk ("quirk !\n");
		}
		warn ("tiglusb_read, NAK received.");
		goto out;
	} else if (result == -EPIPE) {	/* STALL -- shouldn't happen */
		warn ("CLEAR_FEATURE request to remove STALL condition.\n");
		if (usb_clear_halt (s->dev, usb_pipeendpoint (pipe)))
			warn ("send_packet, request failed\n");
		//clear_device(s->dev);
		ret = result;
		goto out;
	} else if (result < 0) {	/* We should not get any I/O errors */
		warn ("funky result: %d. Please notify maintainer.", result);
		ret = -EIO;
		goto out;
	}

	if (copy_to_user (buf, buffer, bytes_read)) {
		ret = -EFAULT;
		goto out;
	}

      out:
	return ret ? ret : bytes_read;
}

static ssize_t tiglusb_write (struct file *file, const char *buf, size_t count, loff_t * ppos)
{
	ptiglusb_t s = (ptiglusb_t) file->private_data;
	ssize_t ret = 0;
	int bytes_to_write = 0;
	int bytes_written = 0;
	int result = 0;
	char buffer[BULK_SND_MAX];
	unsigned int pipe;

	if (*ppos)
		return -ESPIPE;

	if (s->remove_pending)
		return -EIO;

	if (!s->dev)
		return -EIO;

	bytes_to_write = (count >= BULK_SND_MAX) ? BULK_SND_MAX : count;
	if (copy_from_user (buffer, buf, bytes_to_write)) {
		ret = -EFAULT;
		goto out;
	}

	pipe = usb_sndbulkpipe (s->dev, 2);
	result = usb_bulk_msg (s->dev, pipe, buffer, bytes_to_write,
			       &bytes_written, HZ / (timeout / 10));

	if (result == -ETIMEDOUT) {	/* NAK */
		warn ("tiglusb_write, NAK received.");
		ret = result;
		goto out;
	} else if (result == -EPIPE) {	/* STALL -- shouldn't happen */
		warn ("CLEAR_FEATURE request to remove STALL condition.");
		if (usb_clear_halt (s->dev, usb_pipeendpoint (pipe)))
			warn ("send_packet, request failed\n");
		//clear_device(s->dev);
		ret = result;
		goto out;
	} else if (result < 0) {	/* We should not get any I/O errors */
		warn ("funky result: %d. Please notify maintainer.", result);
		ret = -EIO;
		goto out;
	}

	if (bytes_written != bytes_to_write) {
		ret = -EIO;
		goto out;
	}

      out:
	return ret ? ret : bytes_written;
}

static int tiglusb_ioctl (struct inode *inode, struct file *file,
			  unsigned int cmd, unsigned long arg)
{
	ptiglusb_t s = (ptiglusb_t) file->private_data;
	int ret = 0;

	if (s->remove_pending)
		return -EIO;

	down (&s->mutex);

	if (!s->dev) {
		up (&s->mutex);
		return -EIO;
	}

	switch (cmd) {
	case IOCTL_TIUSB_TIMEOUT:
		timeout = arg;	// timeout value in tenth of seconds
		break;
	case IOCTL_TIUSB_RESET_DEVICE:
		printk (KERN_DEBUG "IOCTL_TIGLUSB_RESET_DEVICE\n");
		if (clear_device (s->dev))
			ret = -EIO;
		break;
	case IOCTL_TIUSB_RESET_PIPES:
		printk (KERN_DEBUG "IOCTL_TIGLUSB_RESET_PIPES\n");
		if (clear_pipes (s->dev))
			ret = -EIO;
		break;
	default:
		ret = -ENOTTY;
		break;
	}

	up (&s->mutex);

	return ret;
}

/* ----- kernel module registering ------------------------------------ */

static struct file_operations tiglusb_fops = {
	owner:		THIS_MODULE,
	llseek:		no_llseek,
	read:		tiglusb_read,
	write:		tiglusb_write,
	ioctl:		tiglusb_ioctl,
	open:		tiglusb_open,
	release:	tiglusb_release,
};

static int tiglusb_find_struct (void)
{
	int u;

	for (u = 0; u < MAXTIGL; u++) {
		ptiglusb_t s = &tiglusb[u];
		if (!s->dev)
			return u;
	}

	return -1;
}

/* --- initialisation code ------------------------------------- */

static void *tiglusb_probe (struct usb_device *dev, unsigned int ifnum,
			    const struct usb_device_id *id)
{
	int minor;
	ptiglusb_t s;
	char name[8];

	printk ("tiglusb: probing vendor id 0x%x, device id 0x%x ifnum:%d\n",
		dev->descriptor.idVendor, dev->descriptor.idProduct, ifnum);

	/* 
	 * We don't handle multiple configurations. As of version 0x0103 of 
	 * the TIGL hardware, there's only 1 configuration. 
	 */

	if (dev->descriptor.bNumConfigurations != 1)
		return NULL;

	if ((dev->descriptor.idProduct != 0xe001) && (dev->descriptor.idVendor != 0x451))
		return NULL;

	if (usb_set_configuration (dev, dev->config[0].bConfigurationValue) < 0) {
		printk ("tiglusb_probe: set_configuration failed\n");
		return NULL;
	}

	minor = tiglusb_find_struct ();
	if (minor == -1)
		return NULL;

	s = &tiglusb[minor];

	down (&s->mutex);
	s->remove_pending = 0;
	s->dev = dev;
	up (&s->mutex);
	dbg ("bound to interface: %d", ifnum);

	sprintf (name, "%d", s->minor);
	printk ("tiglusb: registering to devfs : major = %d, minor = %d, node = %s\n", TIUSB_MAJOR,
		(TIUSB_MINOR + s->minor), name);
	s->devfs =
	    devfs_register (devfs_handle, name, DEVFS_FL_DEFAULT, TIUSB_MAJOR,
			    TIUSB_MINOR + s->minor, S_IFCHR | S_IRUGO | S_IWUGO, &tiglusb_fops,
			    NULL);

	/* Display firmware version */
	printk ("tiglusb: link cable version %i.%02x\n",
		dev->descriptor.bcdDevice >> 8, dev->descriptor.bcdDevice & 0xff);

	return s;
}

static void tiglusb_disconnect (struct usb_device *dev, void *drv_context)
{
	ptiglusb_t s = (ptiglusb_t) drv_context;

	if (!s || !s->dev)
		printk ("bogus disconnect");

	s->remove_pending = 1;
	wake_up (&s->wait);
	if (s->state == _started)
		sleep_on (&s->remove_ok);
	down (&s->mutex);
	s->dev = NULL;
	s->opened = 0;

	/* cleanup now or later, on close */
	if (!s->opened)
		usblp_cleanup (s);
	else
		up (&s->mutex);

	/* unregister device */
	devfs_unregister (s->devfs);
	s->devfs = NULL;
	printk ("tiglusb: device disconnected\n");
}

static struct usb_device_id tiglusb_ids[] = {
	{USB_DEVICE (0x0451, 0xe001)},
	{}
};

MODULE_DEVICE_TABLE (usb, tiglusb_ids);

static struct usb_driver tiglusb_driver = {
	owner:		THIS_MODULE,
	name:		"tiglusb",
	probe:		tiglusb_probe,
	disconnect:	tiglusb_disconnect,
	id_table:	tiglusb_ids,
};

/* --- 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 tiglusb_setup (char *str)
{
	int ints[2];

	str = get_options (str, ARRAY_SIZE (ints), ints);

	if (ints[0] > 0) {
		timeout = ints[1];
	}

	return 1;
}
#endif

static int __init tiglusb_init (void)
{
	unsigned u;
	int result;

	/* initialize struct */
	for (u = 0; u < MAXTIGL; u++) {
		ptiglusb_t s = &tiglusb[u];
		memset (s, 0, sizeof (tiglusb_t));
		init_MUTEX (&s->mutex);
		s->dev = NULL;
		s->minor = u;
		s->opened = 0;
		init_waitqueue_head (&s->wait);
		init_waitqueue_head (&s->remove_ok);
	}

	/* register device */
	if (devfs_register_chrdev (TIUSB_MAJOR, "tiglusb", &tiglusb_fops)) {
		printk ("tiglusb: unable to get major %d\n", TIUSB_MAJOR);
		return -EIO;
	}

	/* Use devfs, tree: /dev/ticables/usb/[0..3] */
	devfs_handle = devfs_mk_dir (NULL, "ticables/usb", NULL);

	/* register USB module */
	result = usb_register (&tiglusb_driver);
	if (result < 0) {
		devfs_unregister_chrdev (TIUSB_MAJOR, "tiglusb");
		return -1;
	}

	info (DRIVER_DESC ", " DRIVER_VERSION);

	return 0;
}

static void __exit tiglusb_cleanup (void)
{
	usb_deregister (&tiglusb_driver);
	devfs_unregister (devfs_handle);
	devfs_unregister_chrdev (TIUSB_MAJOR, "tiglusb");
}

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

__setup ("tiusb=", tiglusb_setup);
module_init (tiglusb_init);
module_exit (tiglusb_cleanup);

MODULE_AUTHOR (DRIVER_AUTHOR);
MODULE_DESCRIPTION (DRIVER_DESC);
MODULE_LICENSE (DRIVER_LICENSE);

MODULE_PARM (timeout, "i");
MODULE_PARM_DESC (timeout, "Timeout (default=1.5 seconds)");

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