Staging: vme: add VME userspace driver

Adds a VME userspace access driver

Signed-off-by: Martyn Welch <martyn.welch@gefanuc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 771 insertions, 0 deletions

diff --git a/drivers/staging/vme/devices/vme_user.c b/drivers/staging/vme/devices/vme_user.c
new file mode 100644
index 00000000000..10294ab1c40
--- /dev/null
+++ b/drivers/staging/vme/devices/vme_user.c
@@ -0,0 +1,771 @@
+/*
+ * VMEbus User access driver
+ *
+ * Author: Martyn Welch <martyn.welch@gefanuc.com>
+ * Copyright 2008 GE Fanuc Intelligent Platforms Embedded Systems, Inc.
+ *
+ * Based on work by:
+ *   Tom Armistead and Ajit Prem
+ *     Copyright 2004 Motorola Inc.
+ *
+ *
+ * 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.
+ */
+
+#include <linux/cdev.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/ioctl.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/pci.h>
+#include <linux/semaphore.h>
+#include <linux/spinlock.h>
+#include <linux/syscalls.h>
+#include <linux/types.h>
+#include <linux/version.h>
+
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+#include "../vme.h"
+#include "vme_user.h"
+
+/* Currently Documentation/devices.txt defines the following for VME:
+ *
+ * 221 char	VME bus
+ * 		  0 = /dev/bus/vme/m0		First master image
+ * 		  1 = /dev/bus/vme/m1		Second master image
+ * 		  2 = /dev/bus/vme/m2		Third master image
+ * 		  3 = /dev/bus/vme/m3		Fourth master image
+ * 		  4 = /dev/bus/vme/s0		First slave image
+ * 		  5 = /dev/bus/vme/s1		Second slave image
+ * 		  6 = /dev/bus/vme/s2		Third slave image
+ * 		  7 = /dev/bus/vme/s3		Fourth slave image
+ * 		  8 = /dev/bus/vme/ctl		Control
+ *
+ * 		It is expected that all VME bus drivers will use the
+ * 		same interface.  For interface documentation see
+ * 		http://www.vmelinux.org/.
+ *
+ * However the VME driver at http://www.vmelinux.org/ is rather old and doesn't
+ * even support the tsi148 chipset (which has 8 master and 8 slave windows).
+ * We'll run with this or now as far as possible, however it probably makes
+ * sense to get rid of the old mappings and just do everything dynamically.
+ *
+ * So for now, we'll restrict the driver to providing 4 masters and 4 slaves as
+ * defined above and try to support at least some of the interface from
+ * http://www.vmelinux.org/ as an alternative drive can be written providing a
+ * saner interface later.
+ */
+#define VME_MAJOR	221	/* VME Major Device Number */
+#define VME_DEVS	9	/* Number of dev entries */
+
+#define MASTER_MINOR	0
+#define MASTER_MAX	3
+#define SLAVE_MINOR	4
+#define SLAVE_MAX	7
+#define CONTROL_MINOR	8
+
+#define PCI_BUF_SIZE  0x20000	/* Size of one slave image buffer */
+
+/*
+ * Structure to handle image related parameters.
+ */
+typedef struct {
+	void __iomem *kern_buf;	/* Buffer address in kernel space */
+	dma_addr_t pci_buf;	/* Buffer address in PCI address space */
+	unsigned long long size_buf;	/* Buffer size */
+	struct semaphore sem;	/* Semaphore for locking image */
+	struct device *device;	/* Sysfs device */
+	struct vme_resource *resource;	/* VME resource */
+	int users;		/* Number of current users */
+} image_desc_t;
+static image_desc_t image[VME_DEVS];
+
+typedef struct {
+	unsigned long reads;
+	unsigned long writes;
+	unsigned long ioctls;
+	unsigned long irqs;
+	unsigned long berrs;
+	unsigned long dmaErrors;
+	unsigned long timeouts;
+	unsigned long external;
+} driver_stats_t;
+static driver_stats_t statistics;
+
+struct cdev *vme_user_cdev;		/* Character device */
+struct class *vme_user_sysfs_class;	/* Sysfs class */
+struct device *vme_user_bridge;		/* Pointer to the bridge device */
+
+static char driver_name[] = "vme_user";
+
+static const int type[VME_DEVS] = {	MASTER_MINOR,	MASTER_MINOR,
+					MASTER_MINOR,	MASTER_MINOR,
+					SLAVE_MINOR,	SLAVE_MINOR,
+					SLAVE_MINOR,	SLAVE_MINOR,
+					CONTROL_MINOR
+				};
+
+
+static int vme_user_open(struct inode *, struct file *);
+static int vme_user_release(struct inode *, struct file *);
+static ssize_t vme_user_read(struct file *, char *, size_t, loff_t *);
+static ssize_t vme_user_write(struct file *, const char *, size_t, loff_t *);
+static loff_t vme_user_llseek(struct file *, loff_t, int);
+static int vme_user_ioctl(struct inode *, struct file *, unsigned int,
+	unsigned long);
+
+static int __init vme_user_probe(struct device *dev);
+
+static struct file_operations vme_user_fops = {
+        .open = vme_user_open,
+        .release = vme_user_release,
+        .read = vme_user_read,
+        .write = vme_user_write,
+        .llseek = vme_user_llseek,
+        .ioctl = vme_user_ioctl,
+};
+
+
+/*
+ * Reset all the statistic counters
+ */
+static void reset_counters(void)
+{
+        statistics.reads = 0;
+        statistics.writes = 0;
+        statistics.ioctls = 0;
+        statistics.irqs = 0;
+        statistics.berrs = 0;
+        statistics.dmaErrors = 0;
+        statistics.timeouts = 0;
+}
+
+void lmcall(int monitor)
+{
+	printk("Caught Location Monitor %d access\n", monitor);
+}
+
+static void tests(void)
+{
+	struct vme_resource *dma_res;
+	struct vme_dma_list *dma_list;
+	struct vme_dma_attr *pattern_attr, *vme_attr;
+
+	int retval;
+	unsigned int data;
+
+	printk("Running VME DMA test\n");
+	dma_res = vme_request_dma(vme_user_bridge);
+	dma_list = vme_new_dma_list(dma_res);
+	pattern_attr = vme_dma_pattern_attribute(0x0,
+		VME_DMA_PATTERN_WORD |
+			VME_DMA_PATTERN_INCREMENT);
+	vme_attr = vme_dma_vme_attribute(0x10000, VME_A32,
+		VME_SCT, VME_D32);
+	retval = vme_dma_list_add(dma_list, pattern_attr,
+		vme_attr, 0x10000);
+#if 0
+	vme_dma_free_attribute(vme_attr);
+	vme_attr = vme_dma_vme_attribute(0x20000, VME_A32,
+		VME_SCT, VME_D32);
+	retval = vme_dma_list_add(dma_list, pattern_attr,
+		vme_attr, 0x10000);
+#endif
+	retval = vme_dma_list_exec(dma_list);
+	vme_dma_free_attribute(pattern_attr);
+	vme_dma_free_attribute(vme_attr);
+	vme_dma_list_free(dma_list);
+#if 0
+	printk("Generating a VME interrupt\n");
+	vme_generate_irq(dma_res, 0x3, 0xaa);
+	printk("Interrupt returned\n");
+#endif
+	vme_dma_free(dma_res);
+
+	/* Attempt RMW */
+	data = vme_master_rmw(image[0].resource, 0x80000000, 0x00000000,
+		0x80000000, 0);
+	printk("RMW returned 0x%8.8x\n", data);
+
+
+	/* Location Monitor */
+	printk("vme_lm_set:%d\n", vme_lm_set(vme_user_bridge, 0x60000, VME_A32, VME_SCT | VME_USER | VME_DATA));
+	printk("vme_lm_attach:%d\n", vme_lm_attach(vme_user_bridge, 0, lmcall));
+
+	printk("Board in VME slot:%d\n", vme_slot_get(vme_user_bridge));
+}
+
+static int vme_user_open(struct inode *inode, struct file *file)
+{
+	int err;
+	unsigned int minor = MINOR(inode->i_rdev);
+
+	down(&image[minor].sem);
+	/* Only allow device to be opened if a resource is allocated */
+	if (image[minor].resource == NULL) {
+		printk(KERN_ERR "No resources allocated for device\n");
+		err = -EINVAL;
+		goto err_res;
+	}
+
+	/* Increment user count */
+	image[minor].users++;
+
+	up(&image[minor].sem);
+
+	return 0;
+
+err_res:
+	up(&image[minor].sem);
+
+	return err;
+}
+
+static int vme_user_release(struct inode *inode, struct file *file)
+{
+	unsigned int minor = MINOR(inode->i_rdev);
+
+	down(&image[minor].sem);
+
+	/* Decrement user count */
+	image[minor].users--;
+
+	up(&image[minor].sem);
+
+	return 0;
+}
+
+/*
+ * We are going ot alloc a page during init per window for small transfers.
+ * Small transfers will go VME -> buffer -> user space. Larger (more than a
+ * page) transfers will lock the user space buffer into memory and then
+ * transfer the data directly into the user space buffers.
+ */
+static ssize_t resource_to_user(int minor, char __user *buf, size_t count,
+	loff_t *ppos)
+{
+	ssize_t retval;
+	ssize_t copied = 0;
+
+	if (count <= image[minor].size_buf) {
+		/* We copy to kernel buffer */
+		copied = vme_master_read(image[minor].resource,
+			image[minor].kern_buf, count, *ppos);
+		if (copied < 0) {
+			return (int)copied;
+		}
+
+		retval = __copy_to_user(buf, image[minor].kern_buf,
+			(unsigned long)copied);
+		if (retval != 0) {
+			copied = (copied - retval);
+			printk("User copy failed\n");
+			return -EINVAL;
+		}
+
+	} else {
+		/* XXX Need to write this */
+		printk("Currently don't support large transfers\n");
+		/* Map in pages from userspace */
+
+		/* Call vme_master_read to do the transfer */
+		return -EINVAL;
+	}
+
+	return copied;
+}
+
+/*
+ * We are going ot alloc a page during init per window for small transfers.
+ * Small transfers will go user space -> buffer -> VME. Larger (more than a
+ * page) transfers will lock the user space buffer into memory and then
+ * transfer the data directly from the user space buffers out to VME.
+ */
+static ssize_t resource_from_user(unsigned int minor, const char *buf,
+	size_t count, loff_t *ppos)
+{
+	ssize_t retval;
+	ssize_t copied = 0;
+
+	if (count <= image[minor].size_buf) {
+		retval = __copy_from_user(image[minor].kern_buf, buf,
+			(unsigned long)count);
+		if (retval != 0)
+			copied = (copied - retval);
+		else
+			copied = count;
+
+		copied = vme_master_write(image[minor].resource,
+			image[minor].kern_buf, copied, *ppos);
+	} else {
+		/* XXX Need to write this */
+		printk("Currently don't support large transfers\n");
+		/* Map in pages from userspace */
+
+		/* Call vme_master_write to do the transfer */
+		return -EINVAL;
+	}
+
+	return copied;
+}
+
+static ssize_t buffer_to_user(unsigned int minor, char __user *buf,
+	size_t count, loff_t *ppos)
+{
+	void __iomem *image_ptr;
+	ssize_t retval;
+
+	image_ptr = image[minor].kern_buf + *ppos;
+
+	retval = __copy_to_user(buf, image_ptr, (unsigned long)count);
+	if (retval != 0) {
+		retval = (count - retval);
+		printk(KERN_WARNING "Partial copy to userspace\n");
+	} else
+		retval = count;
+
+	/* Return number of bytes successfully read */
+	return retval;
+}
+
+static ssize_t buffer_from_user(unsigned int minor, const char *buf,
+	size_t count, loff_t *ppos)
+{
+	void __iomem *image_ptr;
+	size_t retval;
+
+	image_ptr = image[minor].kern_buf + *ppos;
+
+	retval = __copy_from_user(image_ptr, buf, (unsigned long)count);
+	if (retval != 0) {
+		retval = (count - retval);
+		printk(KERN_WARNING "Partial copy to userspace\n");
+	} else
+		retval = count;
+
+	/* Return number of bytes successfully read */
+	return retval;
+}
+
+static ssize_t vme_user_read(struct file *file, char *buf, size_t count,
+			loff_t * ppos)
+{
+	unsigned int minor = MINOR(file->f_dentry->d_inode->i_rdev);
+	ssize_t retval;
+	size_t image_size;
+	size_t okcount;
+
+	down(&image[minor].sem);
+
+	/* XXX Do we *really* want this helper - we can use vme_*_get ? */
+	image_size = vme_get_size(image[minor].resource);
+
+	/* Ensure we are starting at a valid location */
+	if ((*ppos < 0) || (*ppos > (image_size - 1))) {
+		up(&image[minor].sem);
+		return 0;
+	}
+
+	/* Ensure not reading past end of the image */
+	if (*ppos + count > image_size)
+		okcount = image_size - *ppos;
+	else
+		okcount = count;
+
+	switch (type[minor]){
+	case MASTER_MINOR:
+		retval = resource_to_user(minor, buf, okcount, ppos);
+		break;
+	case SLAVE_MINOR:
+		retval = buffer_to_user(minor, buf, okcount, ppos);
+		break;
+	default:
+		retval = -EINVAL;
+	}
+
+	up(&image[minor].sem);
+
+	if (retval > 0)
+		*ppos += retval;
+
+	return retval;
+}
+
+static ssize_t vme_user_write(struct file *file, const char *buf, size_t count,
+			 loff_t *ppos)
+{
+	unsigned int minor = MINOR(file->f_dentry->d_inode->i_rdev);
+	ssize_t retval;
+	size_t image_size;
+	size_t okcount;
+
+	down(&image[minor].sem);
+
+	image_size = vme_get_size(image[minor].resource);
+
+	/* Ensure we are starting at a valid location */
+	if ((*ppos < 0) || (*ppos > (image_size - 1))) {
+		up(&image[minor].sem);
+		return 0;
+	}
+
+	/* Ensure not reading past end of the image */
+	if (*ppos + count > image_size)
+		okcount = image_size - *ppos;
+	else
+		okcount = count;
+
+	switch (type[minor]){
+	case MASTER_MINOR:
+		retval = resource_from_user(minor, buf, okcount, ppos);
+		break;
+	case SLAVE_MINOR:
+		retval = buffer_from_user(minor, buf, okcount, ppos);
+		break;
+	default:
+		retval = -EINVAL;
+	}
+
+	up(&image[minor].sem);
+
+	if (retval > 0)
+		*ppos += retval;
+
+	return retval;
+}
+
+static loff_t vme_user_llseek(struct file *file, loff_t off, int whence)
+{
+	printk(KERN_ERR "Llseek currently incomplete\n");
+	return -EINVAL;
+}
+
+static int vme_user_ioctl(struct inode *inode, struct file *file,
+	unsigned int cmd, unsigned long arg)
+{
+	unsigned int minor = MINOR(inode->i_rdev);
+#if 0
+	int ret_val;
+#endif
+	unsigned long copyRet;
+	vme_slave_t slave;
+
+	statistics.ioctls++;
+	switch (type[minor]) {
+	case CONTROL_MINOR:
+		break;
+	case MASTER_MINOR:
+		break;
+	case SLAVE_MINOR:
+		switch (cmd) {
+		case VME_SET_SLAVE:
+
+			copyRet = copy_from_user(&slave, (char *)arg,
+				sizeof(slave));
+			if (copyRet != 0) {
+				printk(KERN_WARNING "Partial copy from "
+					"userspace\n");
+				return -EFAULT;
+			}
+
+			return vme_slave_set(image[minor].resource,
+				slave.enable, slave.vme_addr, slave.size,
+				image[minor].pci_buf, slave.aspace,
+				slave.cycle);
+
+			break;
+#if 0
+		case VME_GET_SLAVE:
+			vme_slave_t slave;
+
+			ret_val = vme_slave_get(minor, &iRegs);
+
+			copyRet = copy_to_user((char *)arg, &slave,
+				sizeof(slave));
+			if (copyRet != 0) {
+				printk(KERN_WARNING "Partial copy to "
+					"userspace\n");
+				return -EFAULT;
+			}
+
+			return ret_val;
+			break;
+#endif
+		}
+		break;
+	}
+
+	return -EINVAL;
+}
+
+
+/*
+ * Unallocate a previously allocated buffer
+ */
+static void buf_unalloc (int num)
+{
+	if (image[num].kern_buf) {
+#ifdef VME_DEBUG
+		printk(KERN_DEBUG "UniverseII:Releasing buffer at %p\n",
+			image[num].pci_buf);
+#endif
+
+		vme_free_consistent(image[num].resource, image[num].size_buf,
+			image[num].kern_buf, image[num].pci_buf);
+
+		image[num].kern_buf = NULL;
+		image[num].pci_buf = 0;
+		image[num].size_buf = 0;
+
+#ifdef VME_DEBUG
+	} else {
+		printk(KERN_DEBUG "UniverseII: Buffer not allocated\n");
+#endif
+	}
+}
+
+static struct vme_driver vme_user_driver = {
+        .name = driver_name,
+        .probe = vme_user_probe,
+};
+
+
+/*
+ * In this simple access driver, the old behaviour is being preserved as much
+ * as practical. We will therefore reserve the buffers and request the images
+ * here so that we don't have to do it later.
+ */
+static int __init vme_bridge_init(void)
+{
+	int retval;
+	printk(KERN_INFO "VME User Space Access Driver\n");
+	printk("vme_user_driver:%p\n", &vme_user_driver);
+	retval = vme_register_driver(&vme_user_driver);
+	printk("vme_register_driver returned %d\n", retval);
+	return retval;
+}
+
+/*
+ * This structure gets passed a device, this should be the device created at
+ * registration.
+ */
+static int __init vme_user_probe(struct device *dev)
+{
+	int i, err;
+	char name[8];
+
+	printk("Running vme_user_probe()\n");
+
+	/* Pointer to the bridge device */
+	vme_user_bridge = dev;
+
+	/* Initialise descriptors */
+	for (i = 0; i < VME_DEVS; i++) {
+		image[i].kern_buf = NULL;
+		image[i].pci_buf = 0;
+		init_MUTEX(&(image[i].sem));
+		image[i].device = NULL;
+		image[i].resource = NULL;
+		image[i].users = 0;
+	}
+
+	/* Initialise statistics counters */
+	reset_counters();
+
+	/* Assign major and minor numbers for the driver */
+	err = register_chrdev_region(MKDEV(VME_MAJOR, 0), VME_DEVS,
+		driver_name);
+	if (err) {
+		printk(KERN_WARNING "%s: Error getting Major Number %d for "
+		"driver.\n", driver_name, VME_MAJOR);
+		goto err_region;
+	}
+
+	/* Register the driver as a char device */
+	vme_user_cdev = cdev_alloc();
+	vme_user_cdev->ops = &vme_user_fops;
+	vme_user_cdev->owner = THIS_MODULE;
+	err = cdev_add(vme_user_cdev, MKDEV(VME_MAJOR, 0), VME_DEVS);
+	if (err) {
+		printk(KERN_WARNING "%s: cdev_all failed\n", driver_name);
+		goto err_char;
+	}
+
+	/* Request slave resources and allocate buffers (128kB wide) */
+	for (i = SLAVE_MINOR; i < (SLAVE_MAX + 1); i++) {
+		/* XXX Need to properly request attributes */
+		image[i].resource = vme_slave_request(vme_user_bridge,
+			VME_A16, VME_SCT);
+		if (image[i].resource == NULL) {
+			printk(KERN_WARNING "Unable to allocate slave "
+				"resource\n");
+			goto err_buf;
+		}
+		image[i].size_buf = PCI_BUF_SIZE;
+		image[i].kern_buf = vme_alloc_consistent(image[i].resource,
+			image[i].size_buf, &(image[i].pci_buf));
+		if (image[i].kern_buf == NULL) {
+			printk(KERN_WARNING "Unable to allocate memory for "
+				"buffer\n");
+			image[i].pci_buf = 0;
+			vme_slave_free(image[i].resource);
+			err = -ENOMEM;
+			goto err_buf;
+		}
+	}
+
+	/*
+	 * Request master resources allocate page sized buffers for small
+	 * reads and writes
+	 */
+	for (i = MASTER_MINOR; i < (MASTER_MAX + 1); i++) {
+		/* XXX Need to properly request attributes */
+		image[i].resource = vme_master_request(vme_user_bridge,
+			VME_A32, VME_SCT, VME_D32);
+		if (image[i].resource == NULL) {
+			printk(KERN_WARNING "Unable to allocate master "
+				"resource\n");
+			goto err_buf;
+		}
+		image[i].size_buf = PAGE_SIZE;
+		image[i].kern_buf = vme_alloc_consistent(image[i].resource,
+			image[i].size_buf, &(image[i].pci_buf));
+		if (image[i].kern_buf == NULL) {
+			printk(KERN_WARNING "Unable to allocate memory for "
+				"buffer\n");
+			image[i].pci_buf = 0;
+			vme_master_free(image[i].resource);
+			err = -ENOMEM;
+			goto err_buf;
+		}
+	}
+
+	/* Setup some debug windows */
+	for (i = SLAVE_MINOR; i < (SLAVE_MAX + 1); i++) {
+		err = vme_slave_set(image[i].resource, 1, 0x4000*(i-4),
+			0x4000, image[i].pci_buf, VME_A16,
+			VME_SCT | VME_SUPER | VME_USER | VME_PROG | VME_DATA);
+		if (err != 0) {
+			printk(KERN_WARNING "Failed to configure window\n");
+			goto err_buf;
+		}
+	}
+	for (i = MASTER_MINOR; i < (MASTER_MAX + 1); i++) {
+		err = vme_master_set(image[i].resource, 1,
+			(0x10000 + (0x10000*i)), 0x10000,
+			VME_A32, VME_SCT | VME_USER | VME_DATA, VME_D32);
+		if (err != 0) {
+			printk(KERN_WARNING "Failed to configure window\n");
+			goto err_buf;
+		}
+	}
+
+	/* Create sysfs entries - on udev systems this creates the dev files */
+	vme_user_sysfs_class = class_create(THIS_MODULE, driver_name);
+	if (IS_ERR(vme_user_sysfs_class)) {
+		printk(KERN_ERR "Error creating vme_user class.\n");
+		err = PTR_ERR(vme_user_sysfs_class);
+		goto err_class;
+	}
+
+	/* Add sysfs Entries */
+	for (i=0; i<VME_DEVS; i++) {
+		switch (type[i]) {
+		case MASTER_MINOR:
+			sprintf(name,"bus/vme/m%%d");
+			break;
+		case CONTROL_MINOR:
+			sprintf(name,"bus/vme/ctl");
+			break;
+		case SLAVE_MINOR:
+			sprintf(name,"bus/vme/s%%d");
+			break;
+		default:
+			err = -EINVAL;
+			goto err_sysfs;
+			break;
+		}
+
+		image[i].device =
+			device_create(vme_user_sysfs_class, NULL,
+				MKDEV(VME_MAJOR, i), NULL, name,
+				(type[i] == SLAVE_MINOR)? i - (MASTER_MAX + 1) : i);
+		if (IS_ERR(image[i].device)) {
+			printk("%s: Error creating sysfs device\n",
+				driver_name);
+			err = PTR_ERR(image[i].device);
+			goto err_sysfs;
+		}
+	}
+
+	/* XXX Run tests */
+	/*
+	tests();
+	*/
+
+	return 0;
+
+	/* Ensure counter set correcty to destroy all sysfs devices */
+	i = VME_DEVS;
+err_sysfs:
+	while (i > 0){
+		i--;
+		device_destroy(vme_user_sysfs_class, MKDEV(VME_MAJOR, i));
+	}
+	class_destroy(vme_user_sysfs_class);
+
+	/* Ensure counter set correcty to unalloc all slave buffers */
+	i = SLAVE_MAX + 1;
+err_buf:
+	while (i > SLAVE_MINOR){
+		i--;
+		vme_slave_set(image[i].resource, 0, 0, 0, 0, VME_A32, 0);
+		vme_slave_free(image[i].resource);
+		buf_unalloc(i);
+	}
+err_class:
+	cdev_del(vme_user_cdev);
+err_char:
+	unregister_chrdev_region(MKDEV(VME_MAJOR, 0), VME_DEVS);
+err_region:
+	return err;
+}
+
+static void __exit vme_bridge_exit(void)
+{
+	int i;
+
+	/* Remove sysfs Entries */
+	for(i=0; i<VME_DEVS; i++) {
+		device_destroy(vme_user_sysfs_class, MKDEV(VME_MAJOR, i));
+	}
+	class_destroy(vme_user_sysfs_class);
+
+	for (i = SLAVE_MINOR; i < (SLAVE_MAX + 1); i++) {
+		buf_unalloc(i);
+	}
+
+	/* Unregister device driver */
+	cdev_del(vme_user_cdev);
+
+	/* Unregiser the major and minor device numbers */
+	unregister_chrdev_region(MKDEV(VME_MAJOR, 0), VME_DEVS);
+}
+
+MODULE_DESCRIPTION("VME User Space Access Driver");
+MODULE_AUTHOR("Martyn Welch <martyn.welch@gefanuc.com");
+MODULE_LICENSE("GPL");
+
+module_init(vme_bridge_init);
+module_exit(vme_bridge_exit);