adutux.c

linux 内核源代码

/*
 * adutux - driver for ADU devices from Ontrak Control Systems
 * This is an experimental driver. Use at your own risk.
 * This driver is not supported by Ontrak Control Systems.
 *
 * Copyright (c) 2003 John Homppi (SCO, leave this notice here)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * derived from the Lego USB Tower driver 0.56:
 * Copyright (c) 2003 David Glance <[e-mail]>
 *               2001 Juergen Stuber <[e-mail]>
 * that was derived from USB Skeleton driver - 0.5
 * Copyright (c) 2001 Greg Kroah-Hartman ([e-mail])
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/mutex.h>
#include <asm/uaccess.h>

#ifdef CONFIG_USB_DEBUG
static int debug = 5;
#else
static int debug = 1;
#endif

/* Use our own dbg macro */
#undef dbg
#define dbg(lvl, format, arg...) 					\
do { 									\
	if (debug >= lvl)						\
		printk(KERN_DEBUG __FILE__ " : " format " \n", ## arg);	\
} while (0)


/* Version Information */
#define DRIVER_VERSION "v0.0.13"
#define DRIVER_AUTHOR "John Homppi"
#define DRIVER_DESC "adutux (see www.ontrak.net)"

/* Module parameters */
module_param(debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");

/* Define these values to match your device */
#define ADU_VENDOR_ID 0x0a07
#define ADU_PRODUCT_ID 0x0064

/* table of devices that work with this driver */
static struct usb_device_id device_table [] = {
	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID) },		/* ADU100 */
	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+20) }, 	/* ADU120 */
	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+30) }, 	/* ADU130 */
	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+100) },	/* ADU200 */
	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+108) },	/* ADU208 */
	{ USB_DEVICE(ADU_VENDOR_ID, ADU_PRODUCT_ID+118) },	/* ADU218 */
	{ }/* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, device_table);

#ifdef CONFIG_USB_DYNAMIC_MINORS
#define ADU_MINOR_BASE	0
#else
#define ADU_MINOR_BASE	67
#endif

/* we can have up to this number of device plugged in at once */
#define MAX_DEVICES	16

#define COMMAND_TIMEOUT	(2*HZ)	/* 60 second timeout for a command */

/*
 * The locking scheme is a vanilla 3-lock:
 *   adu_device.buflock: A spinlock, covers what IRQs touch.
 *   adutux_mutex:       A Static lock to cover open_count. It would also cover
 *                       any globals, but we don't have them in 2.6.
 *   adu_device.mtx:     A mutex to hold across sleepers like copy_from_user.
 *                       It covers all of adu_device, except the open_count
 *                       and what .buflock covers.
 */

/* Structure to hold all of our device specific stuff */
struct adu_device {
	struct mutex		mtx;
	struct usb_device*	udev; /* save off the usb device pointer */
	struct usb_interface*	interface;
	unsigned int		minor; /* the starting minor number for this device */
	char			serial_number[8];

	int			open_count; /* number of times this port has been opened */

	char*			read_buffer_primary;
	int			read_buffer_length;
	char*			read_buffer_secondary;
	int			secondary_head;
	int			secondary_tail;
	spinlock_t		buflock;

	wait_queue_head_t	read_wait;
	wait_queue_head_t	write_wait;

	char*			interrupt_in_buffer;
	struct usb_endpoint_descriptor* interrupt_in_endpoint;
	struct urb*		interrupt_in_urb;
	int			read_urb_finished;

	char*			interrupt_out_buffer;
	struct usb_endpoint_descriptor* interrupt_out_endpoint;
	struct urb*		interrupt_out_urb;
	int			out_urb_finished;
};

static DEFINE_MUTEX(adutux_mutex);

static struct usb_driver adu_driver;

static void adu_debug_data(int level, const char *function, int size,
			   const unsigned char *data)
{
	int i;

	if (debug < level)
		return;

	printk(KERN_DEBUG __FILE__": %s - length = %d, data = ",
	       function, size);
	for (i = 0; i < size; ++i)
		printk("%.2x ", data[i]);
	printk("\n");
}

/**
 * adu_abort_transfers
 *      aborts transfers and frees associated data structures
 */
static void adu_abort_transfers(struct adu_device *dev)
{
	unsigned long flags;

	dbg(2," %s : enter", __FUNCTION__);

	if (dev->udev == NULL) {
		dbg(1," %s : udev is null", __FUNCTION__);
		goto exit;
	}

	/* shutdown transfer */

	/* XXX Anchor these instead */
	spin_lock_irqsave(&dev->buflock, flags);
	if (!dev->read_urb_finished) {
		spin_unlock_irqrestore(&dev->buflock, flags);
		usb_kill_urb(dev->interrupt_in_urb);
	} else
		spin_unlock_irqrestore(&dev->buflock, flags);

	spin_lock_irqsave(&dev->buflock, flags);
	if (!dev->out_urb_finished) {
		spin_unlock_irqrestore(&dev->buflock, flags);
		usb_kill_urb(dev->interrupt_out_urb);
	} else
		spin_unlock_irqrestore(&dev->buflock, flags);

exit:
	dbg(2," %s : leave", __FUNCTION__);
}

static void adu_delete(struct adu_device *dev)
{
	dbg(2, "%s enter", __FUNCTION__);

	/* free data structures */
	usb_free_urb(dev->interrupt_in_urb);
	usb_free_urb(dev->interrupt_out_urb);
	kfree(dev->read_buffer_primary);
	kfree(dev->read_buffer_secondary);
	kfree(dev->interrupt_in_buffer);
	kfree(dev->interrupt_out_buffer);
	kfree(dev);

	dbg(2, "%s : leave", __FUNCTION__);
}

static void adu_interrupt_in_callback(struct urb *urb)
{
	struct adu_device *dev = urb->context;
	int status = urb->status;

	dbg(4," %s : enter, status %d", __FUNCTION__, status);
	adu_debug_data(5, __FUNCTION__, urb->actual_length,
		       urb->transfer_buffer);

	spin_lock(&dev->buflock);

	if (status != 0) {
		if ((status != -ENOENT) && (status != -ECONNRESET) &&
			(status != -ESHUTDOWN)) {
			dbg(1," %s : nonzero status received: %d",
			    __FUNCTION__, status);
		}
		goto exit;
	}

	if (urb->actual_length > 0 && dev->interrupt_in_buffer[0] != 0x00) {
		if (dev->read_buffer_length <
		    (4 * le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize)) -
		     (urb->actual_length)) {
			memcpy (dev->read_buffer_primary +
				dev->read_buffer_length,
				dev->interrupt_in_buffer, urb->actual_length);

			dev->read_buffer_length += urb->actual_length;
			dbg(2," %s reading  %d ", __FUNCTION__,
			    urb->actual_length);
		} else {
			dbg(1," %s : read_buffer overflow", __FUNCTION__);
		}
	}

exit:
	dev->read_urb_finished = 1;
	spin_unlock(&dev->buflock);
	/* always wake up so we recover from errors */
	wake_up_interruptible(&dev->read_wait);
	adu_debug_data(5, __FUNCTION__, urb->actual_length,
		       urb->transfer_buffer);
	dbg(4," %s : leave, status %d", __FUNCTION__, status);
}

static void adu_interrupt_out_callback(struct urb *urb)
{
	struct adu_device *dev = urb->context;
	int status = urb->status;

	dbg(4," %s : enter, status %d", __FUNCTION__, status);
	adu_debug_data(5,__FUNCTION__, urb->actual_length, urb->transfer_buffer);

	if (status != 0) {
		if ((status != -ENOENT) &&
		    (status != -ECONNRESET)) {
			dbg(1, " %s :nonzero status received: %d",
			    __FUNCTION__, status);
		}
		goto exit;
	}

	spin_lock(&dev->buflock);
	dev->out_urb_finished = 1;
	wake_up(&dev->write_wait);
	spin_unlock(&dev->buflock);
exit:

	adu_debug_data(5, __FUNCTION__, urb->actual_length,
		       urb->transfer_buffer);
	dbg(4," %s : leave, status %d", __FUNCTION__, status);
}

static int adu_open(struct inode *inode, struct file *file)
{
	struct adu_device *dev = NULL;
	struct usb_interface *interface;
	int subminor;
	int retval;

	dbg(2,"%s : enter", __FUNCTION__);

	subminor = iminor(inode);

	if ((retval = mutex_lock_interruptible(&adutux_mutex))) {
		dbg(2, "%s : mutex lock failed", __FUNCTION__);
		goto exit_no_lock;
	}

	interface = usb_find_interface(&adu_driver, subminor);
	if (!interface) {
		err("%s - error, can't find device for minor %d",
		    __FUNCTION__, subminor);
		retval = -ENODEV;
		goto exit_no_device;
	}

	dev = usb_get_intfdata(interface);
	if (!dev || !dev->udev) {
		retval = -ENODEV;
		goto exit_no_device;
	}

	/* check that nobody else is using the device */
	if (dev->open_count) {
		retval = -EBUSY;
		goto exit_no_device;
	}

	++dev->open_count;
	dbg(2,"%s : open count %d", __FUNCTION__, dev->open_count);

	/* save device in the file's private structure */
	file->private_data = dev;

	/* initialize in direction */
	dev->read_buffer_length = 0;

	/* fixup first read by having urb waiting for it */
	usb_fill_int_urb(dev->interrupt_in_urb,dev->udev,
			 usb_rcvintpipe(dev->udev,
					dev->interrupt_in_endpoint->bEndpointAddress),
			 dev->interrupt_in_buffer,
			 le16_to_cpu(dev->interrupt_in_endpoint->wMaxPacketSize),
			 adu_interrupt_in_callback, dev,
			 dev->interrupt_in_endpoint->bInterval);
	dev->read_urb_finished = 0;
	if (usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL))
		dev->read_urb_finished = 1;
	/* we ignore failure */
	/* end of fixup for first read */

	/* initialize out direction */
	dev->out_urb_finished = 1;

	retval = 0;

exit_no_device:
	mutex_unlock(&adutux_mutex);
exit_no_lock:
	dbg(2,"%s : leave, return value %d ", __FUNCTION__, retval);
	return retval;
}

static void adu_release_internal(struct adu_device *dev)
{
	dbg(2," %s : enter", __FUNCTION__);

	/* decrement our usage count for the device */
	--dev->open_count;
	dbg(2," %s : open count %d", __FUNCTION__, dev->open_count);
	if (dev->open_count <= 0) {
		adu_abort_transfers(dev);
		dev->open_count = 0;
	}

	dbg(2," %s : leave", __FUNCTION__);
}

static int adu_release(struct inode *inode, struct file *file)
{
	struct adu_device *dev;
	int retval = 0;

	dbg(2," %s : enter", __FUNCTION__);

	if (file == NULL) {
 		dbg(1," %s : file is NULL", __FUNCTION__);
		retval = -ENODEV;
		goto exit;
	}

	dev = file->private_data;
	if (dev == NULL) {
 		dbg(1," %s : object is NULL", __FUNCTION__);
		retval = -ENODEV;
		goto exit;
	}

	mutex_lock(&adutux_mutex); /* not interruptible */

	if (dev->open_count <= 0) {
		dbg(1," %s : device not opened", __FUNCTION__);
		retval = -ENODEV;
		goto exit;
	}

	adu_release_internal(dev);
	if (dev->udev == NULL) {
		/* the device was unplugged before the file was released */
		if (!dev->open_count)	/* ... and we're the last user */
			adu_delete(dev);
	}

exit:
	mutex_unlock(&adutux_mutex);
	dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
	return retval;
}

static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
			loff_t *ppos)
{
	struct adu_device *dev;
	size_t bytes_read = 0;
	size_t bytes_to_read = count;
	int i;
	int retval = 0;
	int timeout = 0;
	int should_submit = 0;
	unsigned long flags;
	DECLARE_WAITQUEUE(wait, current);

	dbg(2," %s : enter, count = %Zd, file=%p", __FUNCTION__, count, file);

	dev = file->private_data;
	dbg(2," %s : dev=%p", __FUNCTION__, dev);

	if (mutex_lock_interruptible(&dev->mtx))
		return -ERESTARTSYS;

	/* verify that the device wasn't unplugged */
	if (dev->udev == NULL) {
		retval = -ENODEV;
		err("No device or device unplugged %d", retval);
		goto exit;
	}

	/* verify that some data was requested */
	if (count == 0) {
		dbg(1," %s : read request of 0 bytes", __FUNCTION__);
		goto exit;
	}

	timeout = COMMAND_TIMEOUT;
	dbg(2," %s : about to start looping", __FUNCTION__);
	while (bytes_to_read) {
		int data_in_secondary = dev->secondary_tail - dev->secondary_head;
		dbg(2," %s : while, data_in_secondary=%d, status=%d",
		    __FUNCTION__, data_in_secondary,
		    dev->interrupt_in_urb->status);

		if (data_in_secondary) {
			/* drain secondary buffer */
			int amount = bytes_to_read < data_in_secondary ? bytes_to_read : data_in_secondary;
			i = copy_to_user(buffer, dev->read_buffer_secondary+dev->secondary_head, amount);
			if (i < 0) {
				retval = -EFAULT;
				goto exit;
			}
			dev->secondary_head += (amount - i);
			bytes_read += (amount - i);
			bytes_to_read -= (amount - i);
			if (i) {
				retval = bytes_read ? bytes_read : -EFAULT;
				goto exit;
			}
		} else {
			/* we check the primary buffer */
			spin_lock_irqsave (&dev->buflock, flags);
			if (dev->read_buffer_length) {
				/* we secure access to the primary */
				char *tmp;
				dbg(2," %s : swap, read_buffer_length = %d",
				    __FUNCTION__, dev->read_buffer_length);
				tmp = dev->read_buffer_secondary;
				dev->read_buffer_secondary = dev->read_buffer_primary;