Root/drivers/misc/enclosure.c

1/*
2 * Enclosure Services
3 *
4 * Copyright (C) 2008 James Bottomley <James.Bottomley@HansenPartnership.com>
5 *
6**-----------------------------------------------------------------------------
7**
8** This program is free software; you can redistribute it and/or
9** modify it under the terms of the GNU General Public License
10** version 2 as published by the Free Software Foundation.
11**
12** This program is distributed in the hope that it will be useful,
13** but WITHOUT ANY WARRANTY; without even the implied warranty of
14** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15** GNU General Public License for more details.
16**
17** You should have received a copy of the GNU General Public License
18** along with this program; if not, write to the Free Software
19** Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20**
21**-----------------------------------------------------------------------------
22*/
23#include <linux/device.h>
24#include <linux/enclosure.h>
25#include <linux/err.h>
26#include <linux/list.h>
27#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/mutex.h>
30#include <linux/slab.h>
31
32static LIST_HEAD(container_list);
33static DEFINE_MUTEX(container_list_lock);
34static struct class enclosure_class;
35
36/**
37 * enclosure_find - find an enclosure given a parent device
38 * @dev: the parent to match against
39 * @start: Optional enclosure device to start from (NULL if none)
40 *
41 * Looks through the list of registered enclosures to find all those
42 * with @dev as a parent. Returns NULL if no enclosure is
43 * found. @start can be used as a starting point to obtain multiple
44 * enclosures per parent (should begin with NULL and then be set to
45 * each returned enclosure device). Obtains a reference to the
46 * enclosure class device which must be released with device_put().
47 * If @start is not NULL, a reference must be taken on it which is
48 * released before returning (this allows a loop through all
49 * enclosures to exit with only the reference on the enclosure of
50 * interest held). Note that the @dev may correspond to the actual
51 * device housing the enclosure, in which case no iteration via @start
52 * is required.
53 */
54struct enclosure_device *enclosure_find(struct device *dev,
55                    struct enclosure_device *start)
56{
57    struct enclosure_device *edev;
58
59    mutex_lock(&container_list_lock);
60    edev = list_prepare_entry(start, &container_list, node);
61    if (start)
62        put_device(&start->edev);
63
64    list_for_each_entry_continue(edev, &container_list, node) {
65        struct device *parent = edev->edev.parent;
66        /* parent might not be immediate, so iterate up to
67         * the root of the tree if necessary */
68        while (parent) {
69            if (parent == dev) {
70                get_device(&edev->edev);
71                mutex_unlock(&container_list_lock);
72                return edev;
73            }
74            parent = parent->parent;
75        }
76    }
77    mutex_unlock(&container_list_lock);
78
79    return NULL;
80}
81EXPORT_SYMBOL_GPL(enclosure_find);
82
83/**
84 * enclosure_for_each_device - calls a function for each enclosure
85 * @fn: the function to call
86 * @data: the data to pass to each call
87 *
88 * Loops over all the enclosures calling the function.
89 *
90 * Note, this function uses a mutex which will be held across calls to
91 * @fn, so it must have non atomic context, and @fn may (although it
92 * should not) sleep or otherwise cause the mutex to be held for
93 * indefinite periods
94 */
95int enclosure_for_each_device(int (*fn)(struct enclosure_device *, void *),
96                  void *data)
97{
98    int error = 0;
99    struct enclosure_device *edev;
100
101    mutex_lock(&container_list_lock);
102    list_for_each_entry(edev, &container_list, node) {
103        error = fn(edev, data);
104        if (error)
105            break;
106    }
107    mutex_unlock(&container_list_lock);
108
109    return error;
110}
111EXPORT_SYMBOL_GPL(enclosure_for_each_device);
112
113/**
114 * enclosure_register - register device as an enclosure
115 *
116 * @dev: device containing the enclosure
117 * @components: number of components in the enclosure
118 *
119 * This sets up the device for being an enclosure. Note that @dev does
120 * not have to be a dedicated enclosure device. It may be some other type
121 * of device that additionally responds to enclosure services
122 */
123struct enclosure_device *
124enclosure_register(struct device *dev, const char *name, int components,
125           struct enclosure_component_callbacks *cb)
126{
127    struct enclosure_device *edev =
128        kzalloc(sizeof(struct enclosure_device) +
129            sizeof(struct enclosure_component)*components,
130            GFP_KERNEL);
131    int err, i;
132
133    BUG_ON(!cb);
134
135    if (!edev)
136        return ERR_PTR(-ENOMEM);
137
138    edev->components = components;
139
140    edev->edev.class = &enclosure_class;
141    edev->edev.parent = get_device(dev);
142    edev->cb = cb;
143    dev_set_name(&edev->edev, "%s", name);
144    err = device_register(&edev->edev);
145    if (err)
146        goto err;
147
148    for (i = 0; i < components; i++)
149        edev->component[i].number = -1;
150
151    mutex_lock(&container_list_lock);
152    list_add_tail(&edev->node, &container_list);
153    mutex_unlock(&container_list_lock);
154
155    return edev;
156
157 err:
158    put_device(edev->edev.parent);
159    kfree(edev);
160    return ERR_PTR(err);
161}
162EXPORT_SYMBOL_GPL(enclosure_register);
163
164static struct enclosure_component_callbacks enclosure_null_callbacks;
165
166/**
167 * enclosure_unregister - remove an enclosure
168 *
169 * @edev: the registered enclosure to remove;
170 */
171void enclosure_unregister(struct enclosure_device *edev)
172{
173    int i;
174
175    mutex_lock(&container_list_lock);
176    list_del(&edev->node);
177    mutex_unlock(&container_list_lock);
178
179    for (i = 0; i < edev->components; i++)
180        if (edev->component[i].number != -1)
181            device_unregister(&edev->component[i].cdev);
182
183    /* prevent any callbacks into service user */
184    edev->cb = &enclosure_null_callbacks;
185    device_unregister(&edev->edev);
186}
187EXPORT_SYMBOL_GPL(enclosure_unregister);
188
189#define ENCLOSURE_NAME_SIZE 64
190
191static void enclosure_link_name(struct enclosure_component *cdev, char *name)
192{
193    strcpy(name, "enclosure_device:");
194    strcat(name, dev_name(&cdev->cdev));
195}
196
197static void enclosure_remove_links(struct enclosure_component *cdev)
198{
199    char name[ENCLOSURE_NAME_SIZE];
200
201    enclosure_link_name(cdev, name);
202    sysfs_remove_link(&cdev->dev->kobj, name);
203    sysfs_remove_link(&cdev->cdev.kobj, "device");
204}
205
206static int enclosure_add_links(struct enclosure_component *cdev)
207{
208    int error;
209    char name[ENCLOSURE_NAME_SIZE];
210
211    error = sysfs_create_link(&cdev->cdev.kobj, &cdev->dev->kobj, "device");
212    if (error)
213        return error;
214
215    enclosure_link_name(cdev, name);
216    error = sysfs_create_link(&cdev->dev->kobj, &cdev->cdev.kobj, name);
217    if (error)
218        sysfs_remove_link(&cdev->cdev.kobj, "device");
219
220    return error;
221}
222
223static void enclosure_release(struct device *cdev)
224{
225    struct enclosure_device *edev = to_enclosure_device(cdev);
226
227    put_device(cdev->parent);
228    kfree(edev);
229}
230
231static void enclosure_component_release(struct device *dev)
232{
233    struct enclosure_component *cdev = to_enclosure_component(dev);
234
235    if (cdev->dev) {
236        enclosure_remove_links(cdev);
237        put_device(cdev->dev);
238    }
239    put_device(dev->parent);
240}
241
242static const struct attribute_group *enclosure_groups[];
243
244/**
245 * enclosure_component_register - add a particular component to an enclosure
246 * @edev: the enclosure to add the component
247 * @num: the device number
248 * @type: the type of component being added
249 * @name: an optional name to appear in sysfs (leave NULL if none)
250 *
251 * Registers the component. The name is optional for enclosures that
252 * give their components a unique name. If not, leave the field NULL
253 * and a name will be assigned.
254 *
255 * Returns a pointer to the enclosure component or an error.
256 */
257struct enclosure_component *
258enclosure_component_register(struct enclosure_device *edev,
259                 unsigned int number,
260                 enum enclosure_component_type type,
261                 const char *name)
262{
263    struct enclosure_component *ecomp;
264    struct device *cdev;
265    int err;
266
267    if (number >= edev->components)
268        return ERR_PTR(-EINVAL);
269
270    ecomp = &edev->component[number];
271
272    if (ecomp->number != -1)
273        return ERR_PTR(-EINVAL);
274
275    ecomp->type = type;
276    ecomp->number = number;
277    cdev = &ecomp->cdev;
278    cdev->parent = get_device(&edev->edev);
279    if (name && name[0])
280        dev_set_name(cdev, "%s", name);
281    else
282        dev_set_name(cdev, "%u", number);
283
284    cdev->release = enclosure_component_release;
285    cdev->groups = enclosure_groups;
286
287    err = device_register(cdev);
288    if (err) {
289        ecomp->number = -1;
290        put_device(cdev);
291        return ERR_PTR(err);
292    }
293
294    return ecomp;
295}
296EXPORT_SYMBOL_GPL(enclosure_component_register);
297
298/**
299 * enclosure_add_device - add a device as being part of an enclosure
300 * @edev: the enclosure device being added to.
301 * @num: the number of the component
302 * @dev: the device being added
303 *
304 * Declares a real device to reside in slot (or identifier) @num of an
305 * enclosure. This will cause the relevant sysfs links to appear.
306 * This function may also be used to change a device associated with
307 * an enclosure without having to call enclosure_remove_device() in
308 * between.
309 *
310 * Returns zero on success or an error.
311 */
312int enclosure_add_device(struct enclosure_device *edev, int component,
313             struct device *dev)
314{
315    struct enclosure_component *cdev;
316
317    if (!edev || component >= edev->components)
318        return -EINVAL;
319
320    cdev = &edev->component[component];
321
322    if (cdev->dev == dev)
323        return -EEXIST;
324
325    if (cdev->dev)
326        enclosure_remove_links(cdev);
327
328    put_device(cdev->dev);
329    cdev->dev = get_device(dev);
330    return enclosure_add_links(cdev);
331}
332EXPORT_SYMBOL_GPL(enclosure_add_device);
333
334/**
335 * enclosure_remove_device - remove a device from an enclosure
336 * @edev: the enclosure device
337 * @num: the number of the component to remove
338 *
339 * Returns zero on success or an error.
340 *
341 */
342int enclosure_remove_device(struct enclosure_device *edev, struct device *dev)
343{
344    struct enclosure_component *cdev;
345    int i;
346
347    if (!edev || !dev)
348        return -EINVAL;
349
350    for (i = 0; i < edev->components; i++) {
351        cdev = &edev->component[i];
352        if (cdev->dev == dev) {
353            enclosure_remove_links(cdev);
354            device_del(&cdev->cdev);
355            put_device(dev);
356            cdev->dev = NULL;
357            return device_add(&cdev->cdev);
358        }
359    }
360    return -ENODEV;
361}
362EXPORT_SYMBOL_GPL(enclosure_remove_device);
363
364/*
365 * sysfs pieces below
366 */
367
368static ssize_t enclosure_show_components(struct device *cdev,
369                     struct device_attribute *attr,
370                     char *buf)
371{
372    struct enclosure_device *edev = to_enclosure_device(cdev);
373
374    return snprintf(buf, 40, "%d\n", edev->components);
375}
376
377static struct device_attribute enclosure_attrs[] = {
378    __ATTR(components, S_IRUGO, enclosure_show_components, NULL),
379    __ATTR_NULL
380};
381
382static struct class enclosure_class = {
383    .name = "enclosure",
384    .owner = THIS_MODULE,
385    .dev_release = enclosure_release,
386    .dev_attrs = enclosure_attrs,
387};
388
389static const char *const enclosure_status [] = {
390    [ENCLOSURE_STATUS_UNSUPPORTED] = "unsupported",
391    [ENCLOSURE_STATUS_OK] = "OK",
392    [ENCLOSURE_STATUS_CRITICAL] = "critical",
393    [ENCLOSURE_STATUS_NON_CRITICAL] = "non-critical",
394    [ENCLOSURE_STATUS_UNRECOVERABLE] = "unrecoverable",
395    [ENCLOSURE_STATUS_NOT_INSTALLED] = "not installed",
396    [ENCLOSURE_STATUS_UNKNOWN] = "unknown",
397    [ENCLOSURE_STATUS_UNAVAILABLE] = "unavailable",
398    [ENCLOSURE_STATUS_MAX] = NULL,
399};
400
401static const char *const enclosure_type [] = {
402    [ENCLOSURE_COMPONENT_DEVICE] = "device",
403    [ENCLOSURE_COMPONENT_ARRAY_DEVICE] = "array device",
404};
405
406static ssize_t get_component_fault(struct device *cdev,
407                   struct device_attribute *attr, char *buf)
408{
409    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
410    struct enclosure_component *ecomp = to_enclosure_component(cdev);
411
412    if (edev->cb->get_fault)
413        edev->cb->get_fault(edev, ecomp);
414    return snprintf(buf, 40, "%d\n", ecomp->fault);
415}
416
417static ssize_t set_component_fault(struct device *cdev,
418                   struct device_attribute *attr,
419                   const char *buf, size_t count)
420{
421    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
422    struct enclosure_component *ecomp = to_enclosure_component(cdev);
423    int val = simple_strtoul(buf, NULL, 0);
424
425    if (edev->cb->set_fault)
426        edev->cb->set_fault(edev, ecomp, val);
427    return count;
428}
429
430static ssize_t get_component_status(struct device *cdev,
431                    struct device_attribute *attr,char *buf)
432{
433    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
434    struct enclosure_component *ecomp = to_enclosure_component(cdev);
435
436    if (edev->cb->get_status)
437        edev->cb->get_status(edev, ecomp);
438    return snprintf(buf, 40, "%s\n", enclosure_status[ecomp->status]);
439}
440
441static ssize_t set_component_status(struct device *cdev,
442                    struct device_attribute *attr,
443                    const char *buf, size_t count)
444{
445    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
446    struct enclosure_component *ecomp = to_enclosure_component(cdev);
447    int i;
448
449    for (i = 0; enclosure_status[i]; i++) {
450        if (strncmp(buf, enclosure_status[i],
451                strlen(enclosure_status[i])) == 0 &&
452            (buf[strlen(enclosure_status[i])] == '\n' ||
453             buf[strlen(enclosure_status[i])] == '\0'))
454            break;
455    }
456
457    if (enclosure_status[i] && edev->cb->set_status) {
458        edev->cb->set_status(edev, ecomp, i);
459        return count;
460    } else
461        return -EINVAL;
462}
463
464static ssize_t get_component_active(struct device *cdev,
465                    struct device_attribute *attr, char *buf)
466{
467    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
468    struct enclosure_component *ecomp = to_enclosure_component(cdev);
469
470    if (edev->cb->get_active)
471        edev->cb->get_active(edev, ecomp);
472    return snprintf(buf, 40, "%d\n", ecomp->active);
473}
474
475static ssize_t set_component_active(struct device *cdev,
476                    struct device_attribute *attr,
477                    const char *buf, size_t count)
478{
479    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
480    struct enclosure_component *ecomp = to_enclosure_component(cdev);
481    int val = simple_strtoul(buf, NULL, 0);
482
483    if (edev->cb->set_active)
484        edev->cb->set_active(edev, ecomp, val);
485    return count;
486}
487
488static ssize_t get_component_locate(struct device *cdev,
489                    struct device_attribute *attr, char *buf)
490{
491    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
492    struct enclosure_component *ecomp = to_enclosure_component(cdev);
493
494    if (edev->cb->get_locate)
495        edev->cb->get_locate(edev, ecomp);
496    return snprintf(buf, 40, "%d\n", ecomp->locate);
497}
498
499static ssize_t set_component_locate(struct device *cdev,
500                    struct device_attribute *attr,
501                    const char *buf, size_t count)
502{
503    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
504    struct enclosure_component *ecomp = to_enclosure_component(cdev);
505    int val = simple_strtoul(buf, NULL, 0);
506
507    if (edev->cb->set_locate)
508        edev->cb->set_locate(edev, ecomp, val);
509    return count;
510}
511
512static ssize_t get_component_type(struct device *cdev,
513                  struct device_attribute *attr, char *buf)
514{
515    struct enclosure_component *ecomp = to_enclosure_component(cdev);
516
517    return snprintf(buf, 40, "%s\n", enclosure_type[ecomp->type]);
518}
519
520
521static DEVICE_ATTR(fault, S_IRUGO | S_IWUSR, get_component_fault,
522            set_component_fault);
523static DEVICE_ATTR(status, S_IRUGO | S_IWUSR, get_component_status,
524           set_component_status);
525static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, get_component_active,
526           set_component_active);
527static DEVICE_ATTR(locate, S_IRUGO | S_IWUSR, get_component_locate,
528           set_component_locate);
529static DEVICE_ATTR(type, S_IRUGO, get_component_type, NULL);
530
531static struct attribute *enclosure_component_attrs[] = {
532    &dev_attr_fault.attr,
533    &dev_attr_status.attr,
534    &dev_attr_active.attr,
535    &dev_attr_locate.attr,
536    &dev_attr_type.attr,
537    NULL
538};
539
540static struct attribute_group enclosure_group = {
541    .attrs = enclosure_component_attrs,
542};
543
544static const struct attribute_group *enclosure_groups[] = {
545    &enclosure_group,
546    NULL
547};
548
549static int __init enclosure_init(void)
550{
551    int err;
552
553    err = class_register(&enclosure_class);
554    if (err)
555        return err;
556
557    return 0;
558}
559
560static void __exit enclosure_exit(void)
561{
562    class_unregister(&enclosure_class);
563}
564
565module_init(enclosure_init);
566module_exit(enclosure_exit);
567
568MODULE_AUTHOR("James Bottomley");
569MODULE_DESCRIPTION("Enclosure Services");
570MODULE_LICENSE("GPL v2");
571

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