1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
|
/*
* VMEbus User access driver
*
* Author: Martyn Welch <martyn.welch@ge.com>
* Copyright 2008 GE 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/atomic.h>
#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/mutex.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/syscalls.h>
#include <linux/types.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/vme.h>
#include "vme_user.h"
static const char driver_name[] = "vme_user";
static int bus[VME_USER_BUS_MAX];
static unsigned int bus_num;
/* 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 for 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 the driver can be written
* providing a saner interface later.
*
* The vmelinux.org driver never supported slave images, the devices reserved
* for slaves were repurposed to support all 8 master images on the UniverseII!
* We shall support 4 masters and 4 slaves with this driver.
*/
#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.
*/
struct image_desc {
void *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 mutex mutex; /* Mutex for locking image */
struct device *device; /* Sysfs device */
struct vme_resource *resource; /* VME resource */
int mmap_count; /* Number of current mmap's */
};
static struct image_desc image[VME_DEVS];
static struct cdev *vme_user_cdev; /* Character device */
static struct class *vme_user_sysfs_class; /* Sysfs class */
static struct vme_dev *vme_user_bridge; /* Pointer to user device */
static const int type[VME_DEVS] = { MASTER_MINOR, MASTER_MINOR,
MASTER_MINOR, MASTER_MINOR,
SLAVE_MINOR, SLAVE_MINOR,
SLAVE_MINOR, SLAVE_MINOR,
CONTROL_MINOR
};
struct vme_user_vma_priv {
unsigned int minor;
atomic_t refcnt;
};
static ssize_t resource_to_user(int minor, char __user *buf, size_t count,
loff_t *ppos)
{
ssize_t copied = 0;
if (count > image[minor].size_buf)
count = image[minor].size_buf;
copied = vme_master_read(image[minor].resource, image[minor].kern_buf,
count, *ppos);
if (copied < 0)
return (int)copied;
if (__copy_to_user(buf, image[minor].kern_buf, (unsigned long)copied))
return -EFAULT;
return copied;
}
static ssize_t resource_from_user(unsigned int minor, const char __user *buf,
size_t count, loff_t *ppos)
{
if (count > image[minor].size_buf)
count = image[minor].size_buf;
if (__copy_from_user(image[minor].kern_buf, buf, (unsigned long)count))
return -EFAULT;
return vme_master_write(image[minor].resource, image[minor].kern_buf,
count, *ppos);
}
static ssize_t buffer_to_user(unsigned int minor, char __user *buf,
size_t count, loff_t *ppos)
{
void *image_ptr;
image_ptr = image[minor].kern_buf + *ppos;
if (__copy_to_user(buf, image_ptr, (unsigned long)count))
return -EFAULT;
return count;
}
static ssize_t buffer_from_user(unsigned int minor, const char __user *buf,
size_t count, loff_t *ppos)
{
void *image_ptr;
image_ptr = image[minor].kern_buf + *ppos;
if (__copy_from_user(image_ptr, buf, (unsigned long)count))
return -EFAULT;
return count;
}
static ssize_t vme_user_read(struct file *file, char __user *buf, size_t count,
loff_t *ppos)
{
unsigned int minor = MINOR(file_inode(file)->i_rdev);
ssize_t retval;
size_t image_size;
if (minor == CONTROL_MINOR)
return 0;
mutex_lock(&image[minor].mutex);
/* 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))) {
mutex_unlock(&image[minor].mutex);
return 0;
}
/* Ensure not reading past end of the image */
if (*ppos + count > image_size)
count = image_size - *ppos;
switch (type[minor]) {
case MASTER_MINOR:
retval = resource_to_user(minor, buf, count, ppos);
break;
case SLAVE_MINOR:
retval = buffer_to_user(minor, buf, count, ppos);
break;
default:
retval = -EINVAL;
}
mutex_unlock(&image[minor].mutex);
if (retval > 0)
*ppos += retval;
return retval;
}
static ssize_t vme_user_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
unsigned int minor = MINOR(file_inode(file)->i_rdev);
ssize_t retval;
size_t image_size;
if (minor == CONTROL_MINOR)
return 0;
mutex_lock(&image[minor].mutex);
image_size = vme_get_size(image[minor].resource);
/* Ensure we are starting at a valid location */
if ((*ppos < 0) || (*ppos > (image_size - 1))) {
mutex_unlock(&image[minor].mutex);
return 0;
}
/* Ensure not reading past end of the image */
if (*ppos + count > image_size)
count = image_size - *ppos;
switch (type[minor]) {
case MASTER_MINOR:
retval = resource_from_user(minor, buf, count, ppos);
break;
case SLAVE_MINOR:
retval = buffer_from_user(minor, buf, count, ppos);
break;
default:
retval = -EINVAL;
}
mutex_unlock(&image[minor].mutex);
if (retval > 0)
*ppos += retval;
return retval;
}
static loff_t vme_user_llseek(struct file *file, loff_t off, int whence)
{
unsigned int minor = MINOR(file_inode(file)->i_rdev);
size_t image_size;
loff_t res;
switch (type[minor]) {
case MASTER_MINOR:
case SLAVE_MINOR:
mutex_lock(&image[minor].mutex);
image_size = vme_get_size(image[minor].resource);
res = fixed_size_llseek(file, off, whence, image_size);
mutex_unlock(&image[minor].mutex);
return res;
}
return -EINVAL;
}
/*
* The ioctls provided by the old VME access method (the one at vmelinux.org)
* are most certainly wrong as the effectively push the registers layout
* through to user space. Given that the VME core can handle multiple bridges,
* with different register layouts this is most certainly not the way to go.
*
* We aren't using the structures defined in the Motorola driver either - these
* are also quite low level, however we should use the definitions that have
* already been defined.
*/
static int vme_user_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct vme_master master;
struct vme_slave slave;
struct vme_irq_id irq_req;
unsigned long copied;
unsigned int minor = MINOR(inode->i_rdev);
int retval;
dma_addr_t pci_addr;
void __user *argp = (void __user *)arg;
switch (type[minor]) {
case CONTROL_MINOR:
switch (cmd) {
case VME_IRQ_GEN:
copied = copy_from_user(&irq_req, argp,
sizeof(struct vme_irq_id));
if (copied != 0) {
pr_warn("Partial copy from userspace\n");
return -EFAULT;
}
return vme_irq_generate(vme_user_bridge,
irq_req.level,
irq_req.statid);
}
break;
case MASTER_MINOR:
switch (cmd) {
case VME_GET_MASTER:
memset(&master, 0, sizeof(struct vme_master));
/* XXX We do not want to push aspace, cycle and width
* to userspace as they are
*/
retval = vme_master_get(image[minor].resource,
&master.enable,
&master.vme_addr,
&master.size, &master.aspace,
&master.cycle, &master.dwidth);
copied = copy_to_user(argp, &master,
sizeof(struct vme_master));
if (copied != 0) {
pr_warn("Partial copy to userspace\n");
return -EFAULT;
}
return retval;
case VME_SET_MASTER:
if (image[minor].mmap_count != 0) {
pr_warn("Can't adjust mapped window\n");
return -EPERM;
}
copied = copy_from_user(&master, argp, sizeof(master));
if (copied != 0) {
pr_warn("Partial copy from userspace\n");
return -EFAULT;
}
/* XXX We do not want to push aspace, cycle and width
* to userspace as they are
*/
return vme_master_set(image[minor].resource,
master.enable, master.vme_addr, master.size,
master.aspace, master.cycle, master.dwidth);
break;
}
break;
case SLAVE_MINOR:
switch (cmd) {
case VME_GET_SLAVE:
memset(&slave, 0, sizeof(struct vme_slave));
/* XXX We do not want to push aspace, cycle and width
* to userspace as they are
*/
retval = vme_slave_get(image[minor].resource,
&slave.enable, &slave.vme_addr,
&slave.size, &pci_addr,
&slave.aspace, &slave.cycle);
copied = copy_to_user(argp, &slave,
sizeof(struct vme_slave));
if (copied != 0) {
pr_warn("Partial copy to userspace\n");
return -EFAULT;
}
return retval;
case VME_SET_SLAVE:
copied = copy_from_user(&slave, argp, sizeof(slave));
if (copied != 0) {
pr_warn("Partial copy from userspace\n");
return -EFAULT;
}
/* XXX We do not want to push aspace, cycle and width
* to userspace as they are
*/
return vme_slave_set(image[minor].resource,
slave.enable, slave.vme_addr, slave.size,
image[minor].pci_buf, slave.aspace,
slave.cycle);
break;
}
break;
}
return -EINVAL;
}
static long
vme_user_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int ret;
struct inode *inode = file_inode(file);
unsigned int minor = MINOR(inode->i_rdev);
mutex_lock(&image[minor].mutex);
ret = vme_user_ioctl(inode, file, cmd, arg);
mutex_unlock(&image[minor].mutex);
return ret;
}
static void vme_user_vm_open(struct vm_area_struct *vma)
{
struct vme_user_vma_priv *vma_priv = vma->vm_private_data;
atomic_inc(&vma_priv->refcnt);
}
static void vme_user_vm_close(struct vm_area_struct *vma)
{
struct vme_user_vma_priv *vma_priv = vma->vm_private_data;
unsigned int minor = vma_priv->minor;
if (!atomic_dec_and_test(&vma_priv->refcnt))
return;
mutex_lock(&image[minor].mutex);
image[minor].mmap_count--;
mutex_unlock(&image[minor].mutex);
kfree(vma_priv);
}
static const struct vm_operations_struct vme_user_vm_ops = {
.open = vme_user_vm_open,
.close = vme_user_vm_close,
};
static int vme_user_master_mmap(unsigned int minor, struct vm_area_struct *vma)
{
int err;
struct vme_user_vma_priv *vma_priv;
mutex_lock(&image[minor].mutex);
err = vme_master_mmap(image[minor].resource, vma);
if (err) {
mutex_unlock(&image[minor].mutex);
return err;
}
vma_priv = kmalloc(sizeof(*vma_priv), GFP_KERNEL);
if (!vma_priv) {
mutex_unlock(&image[minor].mutex);
return -ENOMEM;
}
vma_priv->minor = minor;
atomic_set(&vma_priv->refcnt, 1);
vma->vm_ops = &vme_user_vm_ops;
vma->vm_private_data = vma_priv;
image[minor].mmap_count++;
mutex_unlock(&image[minor].mutex);
return 0;
}
static int vme_user_mmap(struct file *file, struct vm_area_struct *vma)
{
unsigned int minor = MINOR(file_inode(file)->i_rdev);
if (type[minor] == MASTER_MINOR)
return vme_user_master_mmap(minor, vma);
return -ENODEV;
}
static const struct file_operations vme_user_fops = {
.read = vme_user_read,
.write = vme_user_write,
.llseek = vme_user_llseek,
.unlocked_ioctl = vme_user_unlocked_ioctl,
.compat_ioctl = vme_user_unlocked_ioctl,
.mmap = vme_user_mmap,
};
static int vme_user_match(struct vme_dev *vdev)
{
int i;
int cur_bus = vme_bus_num(vdev);
int cur_slot = vme_slot_num(vdev);
for (i = 0; i < bus_num; i++)
if ((cur_bus == bus[i]) && (cur_slot == vdev->num))
return 1;
return 0;
}
/*
* 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 vme_user_probe(struct vme_dev *vdev)
{
int i, err;
char *name;
/* Save pointer to the bridge device */
if (vme_user_bridge) {
dev_err(&vdev->dev, "Driver can only be loaded for 1 device\n");
err = -EINVAL;
goto err_dev;
}
vme_user_bridge = vdev;
/* Initialise descriptors */
for (i = 0; i < VME_DEVS; i++) {
image[i].kern_buf = NULL;
image[i].pci_buf = 0;
mutex_init(&image[i].mutex);
image[i].device = NULL;
image[i].resource = NULL;
}
/* Assign major and minor numbers for the driver */
err = register_chrdev_region(MKDEV(VME_MAJOR, 0), VME_DEVS,
driver_name);
if (err) {
dev_warn(&vdev->dev, "Error getting Major Number %d for driver.\n",
VME_MAJOR);
goto err_region;
}
/* Register the driver as a char device */
vme_user_cdev = cdev_alloc();
if (!vme_user_cdev) {
err = -ENOMEM;
goto err_char;
}
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) {
dev_warn(&vdev->dev, "cdev_all failed\n");
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 */
/* For ca91cx42 bridge there are only two slave windows
* supporting A16 addressing, so we request A24 supported
* by all windows.
*/
image[i].resource = vme_slave_request(vme_user_bridge,
VME_A24, VME_SCT);
if (!image[i].resource) {
dev_warn(&vdev->dev,
"Unable to allocate slave resource\n");
err = -ENOMEM;
goto err_slave;
}
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) {
dev_warn(&vdev->dev,
"Unable to allocate memory for buffer\n");
image[i].pci_buf = 0;
vme_slave_free(image[i].resource);
err = -ENOMEM;
goto err_slave;
}
}
/*
* 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) {
dev_warn(&vdev->dev,
"Unable to allocate master resource\n");
err = -ENOMEM;
goto err_master;
}
image[i].size_buf = PCI_BUF_SIZE;
image[i].kern_buf = kmalloc(image[i].size_buf, GFP_KERNEL);
if (!image[i].kern_buf) {
err = -ENOMEM;
vme_master_free(image[i].resource);
goto err_master;
}
}
/* 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)) {
dev_err(&vdev->dev, "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++) {
int num;
switch (type[i]) {
case MASTER_MINOR:
name = "bus/vme/m%d";
break;
case CONTROL_MINOR:
name = "bus/vme/ctl";
break;
case SLAVE_MINOR:
name = "bus/vme/s%d";
break;
default:
err = -EINVAL;
goto err_sysfs;
}
num = (type[i] == SLAVE_MINOR) ? i - (MASTER_MAX + 1) : i;
image[i].device = device_create(vme_user_sysfs_class, NULL,
MKDEV(VME_MAJOR, i), NULL, name, num);
if (IS_ERR(image[i].device)) {
dev_info(&vdev->dev, "Error creating sysfs device\n");
err = PTR_ERR(image[i].device);
goto err_sysfs;
}
}
return 0;
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 master windows */
i = MASTER_MAX + 1;
err_master:
while (i > MASTER_MINOR) {
i--;
kfree(image[i].kern_buf);
vme_master_free(image[i].resource);
}
/*
* Ensure counter set correcty to unalloc all slave windows and buffers
*/
i = SLAVE_MAX + 1;
err_slave:
while (i > SLAVE_MINOR) {
i--;
vme_free_consistent(image[i].resource, image[i].size_buf,
image[i].kern_buf, image[i].pci_buf);
vme_slave_free(image[i].resource);
}
err_class:
cdev_del(vme_user_cdev);
err_char:
unregister_chrdev_region(MKDEV(VME_MAJOR, 0), VME_DEVS);
err_region:
err_dev:
return err;
}
static int vme_user_remove(struct vme_dev *dev)
{
int i;
/* Remove sysfs Entries */
for (i = 0; i < VME_DEVS; i++) {
mutex_destroy(&image[i].mutex);
device_destroy(vme_user_sysfs_class, MKDEV(VME_MAJOR, i));
}
class_destroy(vme_user_sysfs_class);
for (i = MASTER_MINOR; i < (MASTER_MAX + 1); i++) {
kfree(image[i].kern_buf);
vme_master_free(image[i].resource);
}
for (i = SLAVE_MINOR; i < (SLAVE_MAX + 1); i++) {
vme_slave_set(image[i].resource, 0, 0, 0, 0, VME_A32, 0);
vme_free_consistent(image[i].resource, image[i].size_buf,
image[i].kern_buf, image[i].pci_buf);
vme_slave_free(image[i].resource);
}
/* Unregister device driver */
cdev_del(vme_user_cdev);
/* Unregiser the major and minor device numbers */
unregister_chrdev_region(MKDEV(VME_MAJOR, 0), VME_DEVS);
return 0;
}
static struct vme_driver vme_user_driver = {
.name = driver_name,
.match = vme_user_match,
.probe = vme_user_probe,
.remove = vme_user_remove,
};
static int __init vme_user_init(void)
{
int retval = 0;
pr_info("VME User Space Access Driver\n");
if (bus_num == 0) {
pr_err("No cards, skipping registration\n");
retval = -ENODEV;
goto err_nocard;
}
/* Let's start by supporting one bus, we can support more than one
* in future revisions if that ever becomes necessary.
*/
if (bus_num > VME_USER_BUS_MAX) {
pr_err("Driver only able to handle %d buses\n",
VME_USER_BUS_MAX);
bus_num = VME_USER_BUS_MAX;
}
/*
* Here we just register the maximum number of devices we can and
* leave vme_user_match() to allow only 1 to go through to probe().
* This way, if we later want to allow multiple user access devices,
* we just change the code in vme_user_match().
*/
retval = vme_register_driver(&vme_user_driver, VME_MAX_SLOTS);
if (retval != 0)
goto err_reg;
return retval;
err_reg:
err_nocard:
return retval;
}
static void __exit vme_user_exit(void)
{
vme_unregister_driver(&vme_user_driver);
}
MODULE_PARM_DESC(bus, "Enumeration of VMEbus to which the driver is connected");
module_param_array(bus, int, &bus_num, 0);
MODULE_DESCRIPTION("VME User Space Access Driver");
MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com");
MODULE_LICENSE("GPL");
module_init(vme_user_init);
module_exit(vme_user_exit);
|