vme_user.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * VMEbus User access driver
  4 *
  5 * Author: Martyn Welch <martyn.welch@ge.com>
  6 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
  7 *
  8 * Based on work by:
  9 *   Tom Armistead and Ajit Prem
 10 *     Copyright 2004 Motorola Inc.
 11 */
 12
 13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 14
 15#include <linux/refcount.h>
 16#include <linux/cdev.h>
 17#include <linux/delay.h>
 18#include <linux/device.h>
 19#include <linux/dma-mapping.h>
 20#include <linux/errno.h>
 21#include <linux/init.h>
 22#include <linux/ioctl.h>
 23#include <linux/kernel.h>
 24#include <linux/mm.h>
 25#include <linux/module.h>
 26#include <linux/pagemap.h>
 27#include <linux/pci.h>
 28#include <linux/mutex.h>
 29#include <linux/slab.h>
 30#include <linux/spinlock.h>
 31#include <linux/syscalls.h>
 32#include <linux/types.h>
 33
 34#include <linux/io.h>
 35#include <linux/uaccess.h>
 36
 37#include "vme.h"
 38#include "vme_user.h"
 39
 40#define DRIVER_NAME "vme_user"
 41
 42static int bus[VME_USER_BUS_MAX];
 43static unsigned int bus_num;
 44
 45/* Currently Documentation/admin-guide/devices.rst defines the
 46 * following for VME:
 47 *
 48 * 221 char	VME bus
 49 *		  0 = /dev/bus/vme/m0		First master image
 50 *		  1 = /dev/bus/vme/m1		Second master image
 51 *		  2 = /dev/bus/vme/m2		Third master image
 52 *		  3 = /dev/bus/vme/m3		Fourth master image
 53 *		  4 = /dev/bus/vme/s0		First slave image
 54 *		  5 = /dev/bus/vme/s1		Second slave image
 55 *		  6 = /dev/bus/vme/s2		Third slave image
 56 *		  7 = /dev/bus/vme/s3		Fourth slave image
 57 *		  8 = /dev/bus/vme/ctl		Control
 58 *
 59 *		It is expected that all VME bus drivers will use the
 60 *		same interface.  For interface documentation see
 61 *		http://www.vmelinux.org/.
 62 *
 63 * However the VME driver at http://www.vmelinux.org/ is rather old and doesn't
 64 * even support the tsi148 chipset (which has 8 master and 8 slave windows).
 65 * We'll run with this for now as far as possible, however it probably makes
 66 * sense to get rid of the old mappings and just do everything dynamically.
 67 *
 68 * So for now, we'll restrict the driver to providing 4 masters and 4 slaves as
 69 * defined above and try to support at least some of the interface from
 70 * http://www.vmelinux.org/ as an alternative the driver can be written
 71 * providing a saner interface later.
 72 *
 73 * The vmelinux.org driver never supported slave images, the devices reserved
 74 * for slaves were repurposed to support all 8 master images on the UniverseII!
 75 * We shall support 4 masters and 4 slaves with this driver.
 76 */
 77#define VME_MAJOR	221	/* VME Major Device Number */
 78#define VME_DEVS	9	/* Number of dev entries */
 79
 80#define MASTER_MINOR	0
 81#define MASTER_MAX	3
 82#define SLAVE_MINOR	4
 83#define SLAVE_MAX	7
 84#define CONTROL_MINOR	8
 85
 86#define PCI_BUF_SIZE  0x20000	/* Size of one slave image buffer */
 87
 88/*
 89 * Structure to handle image related parameters.
 90 */
 91struct image_desc {
 92	void *kern_buf;	/* Buffer address in kernel space */
 93	dma_addr_t pci_buf;	/* Buffer address in PCI address space */
 94	unsigned long long size_buf;	/* Buffer size */
 95	struct mutex mutex;	/* Mutex for locking image */
 96	struct device *device;	/* Sysfs device */
 97	struct vme_resource *resource;	/* VME resource */
 98	int mmap_count;		/* Number of current mmap's */
 99};
100
101static struct image_desc image[VME_DEVS];
102
103static struct cdev *vme_user_cdev;		/* Character device */
104static struct vme_dev *vme_user_bridge;		/* Pointer to user device */
105
106static const struct class vme_user_sysfs_class = {
107	.name = DRIVER_NAME,
108};
109
110static const int type[VME_DEVS] = {	MASTER_MINOR,	MASTER_MINOR,
111					MASTER_MINOR,	MASTER_MINOR,
112					SLAVE_MINOR,	SLAVE_MINOR,
113					SLAVE_MINOR,	SLAVE_MINOR,
114					CONTROL_MINOR
115				};
116
117struct vme_user_vma_priv {
118	unsigned int minor;
119	refcount_t refcnt;
120};
121
122static ssize_t resource_to_user(int minor, char __user *buf, size_t count,
123				loff_t *ppos)
124{
125	ssize_t copied = 0;
126
127	if (count > image[minor].size_buf)
128		count = image[minor].size_buf;
129
130	copied = vme_master_read(image[minor].resource, image[minor].kern_buf,
131				 count, *ppos);
132	if (copied < 0)
133		return (int)copied;
134
135	if (copy_to_user(buf, image[minor].kern_buf, (unsigned long)copied))
136		return -EFAULT;
137
138	return copied;
139}
140
141static ssize_t resource_from_user(unsigned int minor, const char __user *buf,
142				  size_t count, loff_t *ppos)
143{
144	if (count > image[minor].size_buf)
145		count = image[minor].size_buf;
146
147	if (copy_from_user(image[minor].kern_buf, buf, (unsigned long)count))
148		return -EFAULT;
149
150	return vme_master_write(image[minor].resource, image[minor].kern_buf,
151				count, *ppos);
152}
153
154static ssize_t buffer_to_user(unsigned int minor, char __user *buf,
155			      size_t count, loff_t *ppos)
156{
157	void *image_ptr;
158
159	image_ptr = image[minor].kern_buf + *ppos;
160	if (copy_to_user(buf, image_ptr, (unsigned long)count))
161		return -EFAULT;
162
163	return count;
164}
165
166static ssize_t buffer_from_user(unsigned int minor, const char __user *buf,
167				size_t count, loff_t *ppos)
168{
169	void *image_ptr;
170
171	image_ptr = image[minor].kern_buf + *ppos;
172	if (copy_from_user(image_ptr, buf, (unsigned long)count))
173		return -EFAULT;
174
175	return count;
176}
177
178static ssize_t vme_user_read(struct file *file, char __user *buf, size_t count,
179			     loff_t *ppos)
180{
181	unsigned int minor = iminor(file_inode(file));
182	ssize_t retval;
183	size_t image_size;
184
185	if (minor == CONTROL_MINOR)
186		return 0;
187
188	mutex_lock(&image[minor].mutex);
189
190	/* XXX Do we *really* want this helper - we can use vme_*_get ? */
191	image_size = vme_get_size(image[minor].resource);
192
193	/* Ensure we are starting at a valid location */
194	if ((*ppos < 0) || (*ppos > (image_size - 1))) {
195		mutex_unlock(&image[minor].mutex);
196		return 0;
197	}
198
199	/* Ensure not reading past end of the image */
200	if (*ppos + count > image_size)
201		count = image_size - *ppos;
202
203	switch (type[minor]) {
204	case MASTER_MINOR:
205		retval = resource_to_user(minor, buf, count, ppos);
206		break;
207	case SLAVE_MINOR:
208		retval = buffer_to_user(minor, buf, count, ppos);
209		break;
210	default:
211		retval = -EINVAL;
212	}
213
214	mutex_unlock(&image[minor].mutex);
215	if (retval > 0)
216		*ppos += retval;
217
218	return retval;
219}
220
221static ssize_t vme_user_write(struct file *file, const char __user *buf,
222			      size_t count, loff_t *ppos)
223{
224	unsigned int minor = iminor(file_inode(file));
225	ssize_t retval;
226	size_t image_size;
227
228	if (minor == CONTROL_MINOR)
229		return 0;
230
231	mutex_lock(&image[minor].mutex);
232
233	image_size = vme_get_size(image[minor].resource);
234
235	/* Ensure we are starting at a valid location */
236	if ((*ppos < 0) || (*ppos > (image_size - 1))) {
237		mutex_unlock(&image[minor].mutex);
238		return 0;
239	}
240
241	/* Ensure not reading past end of the image */
242	if (*ppos + count > image_size)
243		count = image_size - *ppos;
244
245	switch (type[minor]) {
246	case MASTER_MINOR:
247		retval = resource_from_user(minor, buf, count, ppos);
248		break;
249	case SLAVE_MINOR:
250		retval = buffer_from_user(minor, buf, count, ppos);
251		break;
252	default:
253		retval = -EINVAL;
254	}
255
256	mutex_unlock(&image[minor].mutex);
257
258	if (retval > 0)
259		*ppos += retval;
260
261	return retval;
262}
263
264static loff_t vme_user_llseek(struct file *file, loff_t off, int whence)
265{
266	unsigned int minor = iminor(file_inode(file));
267	size_t image_size;
268	loff_t res;
269
270	switch (type[minor]) {
271	case MASTER_MINOR:
272	case SLAVE_MINOR:
273		mutex_lock(&image[minor].mutex);
274		image_size = vme_get_size(image[minor].resource);
275		res = fixed_size_llseek(file, off, whence, image_size);
276		mutex_unlock(&image[minor].mutex);
277		return res;
278	}
279
280	return -EINVAL;
281}
282
283/*
284 * The ioctls provided by the old VME access method (the one at vmelinux.org)
285 * are most certainly wrong as the effectively push the registers layout
286 * through to user space. Given that the VME core can handle multiple bridges,
287 * with different register layouts this is most certainly not the way to go.
288 *
289 * We aren't using the structures defined in the Motorola driver either - these
290 * are also quite low level, however we should use the definitions that have
291 * already been defined.
292 */
293static int vme_user_ioctl(struct inode *inode, struct file *file,
294			  unsigned int cmd, unsigned long arg)
295{
296	struct vme_master master;
297	struct vme_slave slave;
298	struct vme_irq_id irq_req;
299	unsigned long copied;
300	unsigned int minor = iminor(inode);
301	int retval;
302	dma_addr_t pci_addr;
303	void __user *argp = (void __user *)arg;
304
305	switch (type[minor]) {
306	case CONTROL_MINOR:
307		switch (cmd) {
308		case VME_IRQ_GEN:
309			copied = copy_from_user(&irq_req, argp,
310						sizeof(irq_req));
311			if (copied) {
312				pr_warn("Partial copy from userspace\n");
313				return -EFAULT;
314			}
315
316			return vme_irq_generate(vme_user_bridge,
317						  irq_req.level,
318						  irq_req.statid);
319		}
320		break;
321	case MASTER_MINOR:
322		switch (cmd) {
323		case VME_GET_MASTER:
324			memset(&master, 0, sizeof(master));
325
326			/* XXX	We do not want to push aspace, cycle and width
327			 *	to userspace as they are
328			 */
329			retval = vme_master_get(image[minor].resource,
330						&master.enable,
331						&master.vme_addr,
332						&master.size, &master.aspace,
333						&master.cycle, &master.dwidth);
334
335			copied = copy_to_user(argp, &master,
336					      sizeof(master));
337			if (copied) {
338				pr_warn("Partial copy to userspace\n");
339				return -EFAULT;
340			}
341
342			return retval;
343
344		case VME_SET_MASTER:
345
346			if (image[minor].mmap_count != 0) {
347				pr_warn("Can't adjust mapped window\n");
348				return -EPERM;
349			}
350
351			copied = copy_from_user(&master, argp, sizeof(master));
352			if (copied) {
353				pr_warn("Partial copy from userspace\n");
354				return -EFAULT;
355			}
356
357			/* XXX	We do not want to push aspace, cycle and width
358			 *	to userspace as they are
359			 */
360			return vme_master_set(image[minor].resource,
361				master.enable, master.vme_addr, master.size,
362				master.aspace, master.cycle, master.dwidth);
363
364			break;
365		}
366		break;
367	case SLAVE_MINOR:
368		switch (cmd) {
369		case VME_GET_SLAVE:
370			memset(&slave, 0, sizeof(slave));
371
372			/* XXX	We do not want to push aspace, cycle and width
373			 *	to userspace as they are
374			 */
375			retval = vme_slave_get(image[minor].resource,
376					       &slave.enable, &slave.vme_addr,
377					       &slave.size, &pci_addr,
378					       &slave.aspace, &slave.cycle);
379
380			copied = copy_to_user(argp, &slave,
381					      sizeof(slave));
382			if (copied) {
383				pr_warn("Partial copy to userspace\n");
384				return -EFAULT;
385			}
386
387			return retval;
388
389		case VME_SET_SLAVE:
390
391			copied = copy_from_user(&slave, argp, sizeof(slave));
392			if (copied) {
393				pr_warn("Partial copy from userspace\n");
394				return -EFAULT;
395			}
396
397			/* XXX	We do not want to push aspace, cycle and width
398			 *	to userspace as they are
399			 */
400			return vme_slave_set(image[minor].resource,
401				slave.enable, slave.vme_addr, slave.size,
402				image[minor].pci_buf, slave.aspace,
403				slave.cycle);
404
405			break;
406		}
407		break;
408	}
409
410	return -EINVAL;
411}
412
413static long
414vme_user_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
415{
416	int ret;
417	struct inode *inode = file_inode(file);
418	unsigned int minor = iminor(inode);
419
420	mutex_lock(&image[minor].mutex);
421	ret = vme_user_ioctl(inode, file, cmd, arg);
422	mutex_unlock(&image[minor].mutex);
423
424	return ret;
425}
426
427static void vme_user_vm_open(struct vm_area_struct *vma)
428{
429	struct vme_user_vma_priv *vma_priv = vma->vm_private_data;
430
431	refcount_inc(&vma_priv->refcnt);
432}
433
434static void vme_user_vm_close(struct vm_area_struct *vma)
435{
436	struct vme_user_vma_priv *vma_priv = vma->vm_private_data;
437	unsigned int minor = vma_priv->minor;
438
439	if (!refcount_dec_and_test(&vma_priv->refcnt))
440		return;
441
442	mutex_lock(&image[minor].mutex);
443	image[minor].mmap_count--;
444	mutex_unlock(&image[minor].mutex);
445
446	kfree(vma_priv);
447}
448
449static const struct vm_operations_struct vme_user_vm_ops = {
450	.open = vme_user_vm_open,
451	.close = vme_user_vm_close,
452};
453
454static int vme_user_master_mmap(unsigned int minor, struct vm_area_struct *vma)
455{
456	int err;
457	struct vme_user_vma_priv *vma_priv;
458
459	mutex_lock(&image[minor].mutex);
460
461	err = vme_master_mmap(image[minor].resource, vma);
462	if (err) {
463		mutex_unlock(&image[minor].mutex);
464		return err;
465	}
466
467	vma_priv = kmalloc(sizeof(*vma_priv), GFP_KERNEL);
468	if (!vma_priv) {
469		mutex_unlock(&image[minor].mutex);
470		return -ENOMEM;
471	}
472
473	vma_priv->minor = minor;
474	refcount_set(&vma_priv->refcnt, 1);
475	vma->vm_ops = &vme_user_vm_ops;
476	vma->vm_private_data = vma_priv;
477
478	image[minor].mmap_count++;
479
480	mutex_unlock(&image[minor].mutex);
481
482	return 0;
483}
484
485static int vme_user_mmap(struct file *file, struct vm_area_struct *vma)
486{
487	unsigned int minor = iminor(file_inode(file));
488
489	if (type[minor] == MASTER_MINOR)
490		return vme_user_master_mmap(minor, vma);
491
492	return -ENODEV;
493}
494
495static const struct file_operations vme_user_fops = {
496	.read = vme_user_read,
497	.write = vme_user_write,
498	.llseek = vme_user_llseek,
499	.unlocked_ioctl = vme_user_unlocked_ioctl,
500	.compat_ioctl = compat_ptr_ioctl,
501	.mmap = vme_user_mmap,
502};
503
504static int vme_user_match(struct vme_dev *vdev)
505{
506	int i;
507
508	int cur_bus = vme_bus_num(vdev);
509	int cur_slot = vme_slot_num(vdev);
510
511	for (i = 0; i < bus_num; i++)
512		if ((cur_bus == bus[i]) && (cur_slot == vdev->num))
513			return 1;
514
515	return 0;
516}
517
518/*
519 * In this simple access driver, the old behaviour is being preserved as much
520 * as practical. We will therefore reserve the buffers and request the images
521 * here so that we don't have to do it later.
522 */
523static int vme_user_probe(struct vme_dev *vdev)
524{
525	int i, err;
526	char *name;
527
528	/* Save pointer to the bridge device */
529	if (vme_user_bridge) {
530		dev_err(&vdev->dev, "Driver can only be loaded for 1 device\n");
531		err = -EINVAL;
532		goto err_dev;
533	}
534	vme_user_bridge = vdev;
535
536	/* Initialise descriptors */
537	for (i = 0; i < VME_DEVS; i++) {
538		image[i].kern_buf = NULL;
539		image[i].pci_buf = 0;
540		mutex_init(&image[i].mutex);
541		image[i].device = NULL;
542		image[i].resource = NULL;
543	}
544
545	/* Assign major and minor numbers for the driver */
546	err = register_chrdev_region(MKDEV(VME_MAJOR, 0), VME_DEVS, DRIVER_NAME);
547	if (err) {
548		dev_warn(&vdev->dev, "Error getting Major Number %d for driver.\n",
549			 VME_MAJOR);
550		goto err_region;
551	}
552
553	/* Register the driver as a char device */
554	vme_user_cdev = cdev_alloc();
555	if (!vme_user_cdev) {
556		err = -ENOMEM;
557		goto err_char;
558	}
559	vme_user_cdev->ops = &vme_user_fops;
560	vme_user_cdev->owner = THIS_MODULE;
561	err = cdev_add(vme_user_cdev, MKDEV(VME_MAJOR, 0), VME_DEVS);
562	if (err)
563		goto err_class;
564
565	/* Request slave resources and allocate buffers (128kB wide) */
566	for (i = SLAVE_MINOR; i < (SLAVE_MAX + 1); i++) {
567		/* XXX Need to properly request attributes */
568		/* For ca91cx42 bridge there are only two slave windows
569		 * supporting A16 addressing, so we request A24 supported
570		 * by all windows.
571		 */
572		image[i].resource = vme_slave_request(vme_user_bridge,
573						      VME_A24, VME_SCT);
574		if (!image[i].resource) {
575			dev_warn(&vdev->dev,
576				 "Unable to allocate slave resource\n");
577			err = -ENOMEM;
578			goto err_slave;
579		}
580		image[i].size_buf = PCI_BUF_SIZE;
581		image[i].kern_buf = vme_alloc_consistent(image[i].resource,
582							 image[i].size_buf,
583							 &image[i].pci_buf);
584		if (!image[i].kern_buf) {
585			dev_warn(&vdev->dev,
586				 "Unable to allocate memory for buffer\n");
587			image[i].pci_buf = 0;
588			vme_slave_free(image[i].resource);
589			err = -ENOMEM;
590			goto err_slave;
591		}
592	}
593
594	/*
595	 * Request master resources allocate page sized buffers for small
596	 * reads and writes
597	 */
598	for (i = MASTER_MINOR; i < (MASTER_MAX + 1); i++) {
599		/* XXX Need to properly request attributes */
600		image[i].resource = vme_master_request(vme_user_bridge,
601						       VME_A32, VME_SCT,
602						       VME_D32);
603		if (!image[i].resource) {
604			dev_warn(&vdev->dev,
605				 "Unable to allocate master resource\n");
606			err = -ENOMEM;
607			goto err_master;
608		}
609		image[i].size_buf = PCI_BUF_SIZE;
610		image[i].kern_buf = kmalloc(image[i].size_buf, GFP_KERNEL);
611		if (!image[i].kern_buf) {
612			err = -ENOMEM;
613			vme_master_free(image[i].resource);
614			goto err_master;
615		}
616	}
617
618	/* Create sysfs entries - on udev systems this creates the dev files */
619	err = class_register(&vme_user_sysfs_class);
620	if (err) {
621		dev_err(&vdev->dev, "Error creating vme_user class.\n");
622		goto err_master;
623	}
624
625	/* Add sysfs Entries */
626	for (i = 0; i < VME_DEVS; i++) {
627		int num;
628
629		switch (type[i]) {
630		case MASTER_MINOR:
631			name = "bus/vme/m%d";
632			break;
633		case CONTROL_MINOR:
634			name = "bus/vme/ctl";
635			break;
636		case SLAVE_MINOR:
637			name = "bus/vme/s%d";
638			break;
639		default:
640			err = -EINVAL;
641			goto err_sysfs;
642		}
643
644		num = (type[i] == SLAVE_MINOR) ? i - (MASTER_MAX + 1) : i;
645		image[i].device = device_create(&vme_user_sysfs_class, NULL,
646						MKDEV(VME_MAJOR, i), NULL,
647						name, num);
648		if (IS_ERR(image[i].device)) {
649			dev_info(&vdev->dev, "Error creating sysfs device\n");
650			err = PTR_ERR(image[i].device);
651			goto err_sysfs;
652		}
653	}
654
655	return 0;
656
657err_sysfs:
658	while (i > 0) {
659		i--;
660		device_destroy(&vme_user_sysfs_class, MKDEV(VME_MAJOR, i));
661	}
662	class_unregister(&vme_user_sysfs_class);
663
664	/* Ensure counter set correctly to unalloc all master windows */
665	i = MASTER_MAX + 1;
666err_master:
667	while (i > MASTER_MINOR) {
668		i--;
669		kfree(image[i].kern_buf);
670		vme_master_free(image[i].resource);
671	}
672
673	/*
674	 * Ensure counter set correctly to unalloc all slave windows and buffers
675	 */
676	i = SLAVE_MAX + 1;
677err_slave:
678	while (i > SLAVE_MINOR) {
679		i--;
680		vme_free_consistent(image[i].resource, image[i].size_buf,
681				    image[i].kern_buf, image[i].pci_buf);
682		vme_slave_free(image[i].resource);
683	}
684err_class:
685	cdev_del(vme_user_cdev);
686err_char:
687	unregister_chrdev_region(MKDEV(VME_MAJOR, 0), VME_DEVS);
688err_region:
689err_dev:
690	return err;
691}
692
693static void vme_user_remove(struct vme_dev *dev)
694{
695	int i;
696
697	/* Remove sysfs Entries */
698	for (i = 0; i < VME_DEVS; i++) {
699		mutex_destroy(&image[i].mutex);
700		device_destroy(&vme_user_sysfs_class, MKDEV(VME_MAJOR, i));
701	}
702	class_unregister(&vme_user_sysfs_class);
703
704	for (i = MASTER_MINOR; i < (MASTER_MAX + 1); i++) {
705		kfree(image[i].kern_buf);
706		vme_master_free(image[i].resource);
707	}
708
709	for (i = SLAVE_MINOR; i < (SLAVE_MAX + 1); i++) {
710		vme_slave_set(image[i].resource, 0, 0, 0, 0, VME_A32, 0);
711		vme_free_consistent(image[i].resource, image[i].size_buf,
712				    image[i].kern_buf, image[i].pci_buf);
713		vme_slave_free(image[i].resource);
714	}
715
716	/* Unregister device driver */
717	cdev_del(vme_user_cdev);
718
719	/* Unregister the major and minor device numbers */
720	unregister_chrdev_region(MKDEV(VME_MAJOR, 0), VME_DEVS);
721}
722
723static struct vme_driver vme_user_driver = {
724	.name = DRIVER_NAME,
725	.match = vme_user_match,
726	.probe = vme_user_probe,
727	.remove = vme_user_remove,
728};
729
730static int __init vme_user_init(void)
731{
732	int retval = 0;
733
734	pr_info("VME User Space Access Driver\n");
735
736	if (bus_num == 0) {
737		pr_err("No cards, skipping registration\n");
738		retval = -ENODEV;
739		goto err_nocard;
740	}
741
742	/* Let's start by supporting one bus, we can support more than one
743	 * in future revisions if that ever becomes necessary.
744	 */
745	if (bus_num > VME_USER_BUS_MAX) {
746		pr_err("Driver only able to handle %d buses\n",
747		       VME_USER_BUS_MAX);
748		bus_num = VME_USER_BUS_MAX;
749	}
750
751	/*
752	 * Here we just register the maximum number of devices we can and
753	 * leave vme_user_match() to allow only 1 to go through to probe().
754	 * This way, if we later want to allow multiple user access devices,
755	 * we just change the code in vme_user_match().
756	 */
757	retval = vme_register_driver(&vme_user_driver, VME_MAX_SLOTS);
758	if (retval)
759		goto err_reg;
760
761	return retval;
762
763err_reg:
764err_nocard:
765	return retval;
766}
767
768static void __exit vme_user_exit(void)
769{
770	vme_unregister_driver(&vme_user_driver);
771}
772
773MODULE_PARM_DESC(bus, "Enumeration of VMEbus to which the driver is connected");
774module_param_array(bus, int, &bus_num, 0000);
775
776MODULE_DESCRIPTION("VME User Space Access Driver");
777MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
778MODULE_LICENSE("GPL");
779
780module_init(vme_user_init);
781module_exit(vme_user_exit);