summaryrefslogtreecommitdiffstats
path: root/drivers/pci/hotplug/pci_hotplug_core.c
blob: 5ac31f683b85362c1bca32cbc01a9c77a51a4202 (plain)
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
// SPDX-License-Identifier: GPL-2.0+
/*
 * PCI HotPlug Controller Core
 *
 * Copyright (C) 2001-2002 Greg Kroah-Hartman (greg@kroah.com)
 * Copyright (C) 2001-2002 IBM Corp.
 *
 * All rights reserved.
 *
 * Send feedback to <kristen.c.accardi@intel.com>
 *
 * Authors:
 *   Greg Kroah-Hartman <greg@kroah.com>
 *   Scott Murray <scottm@somanetworks.com>
 */

#include <linux/module.h>	/* try_module_get & module_put */
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/pagemap.h>
#include <linux/init.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/uaccess.h>
#include "../pci.h"
#include "cpci_hotplug.h"

#define MY_NAME	"pci_hotplug"

#define dbg(fmt, arg...) do { if (debug) printk(KERN_DEBUG "%s: %s: " fmt, MY_NAME, __func__, ## arg); } while (0)
#define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME, ## arg)
#define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME, ## arg)
#define warn(format, arg...) printk(KERN_WARNING "%s: " format, MY_NAME, ## arg)

/* local variables */
static bool debug;

static LIST_HEAD(pci_hotplug_slot_list);
static DEFINE_MUTEX(pci_hp_mutex);

/* Weee, fun with macros... */
#define GET_STATUS(name, type)	\
static int get_##name(struct hotplug_slot *slot, type *value)		\
{									\
	const struct hotplug_slot_ops *ops = slot->ops;			\
	int retval = 0;							\
	if (!try_module_get(slot->owner))				\
		return -ENODEV;						\
	if (ops->get_##name)						\
		retval = ops->get_##name(slot, value);			\
	module_put(slot->owner);					\
	return retval;							\
}

GET_STATUS(power_status, u8)
GET_STATUS(attention_status, u8)
GET_STATUS(latch_status, u8)
GET_STATUS(adapter_status, u8)

static ssize_t power_read_file(struct pci_slot *pci_slot, char *buf)
{
	int retval;
	u8 value;

	retval = get_power_status(pci_slot->hotplug, &value);
	if (retval)
		return retval;

	return sprintf(buf, "%d\n", value);
}

static ssize_t power_write_file(struct pci_slot *pci_slot, const char *buf,
				size_t count)
{
	struct hotplug_slot *slot = pci_slot->hotplug;
	unsigned long lpower;
	u8 power;
	int retval = 0;

	lpower = simple_strtoul(buf, NULL, 10);
	power = (u8)(lpower & 0xff);
	dbg("power = %d\n", power);

	if (!try_module_get(slot->owner)) {
		retval = -ENODEV;
		goto exit;
	}
	switch (power) {
	case 0:
		if (slot->ops->disable_slot)
			retval = slot->ops->disable_slot(slot);
		break;

	case 1:
		if (slot->ops->enable_slot)
			retval = slot->ops->enable_slot(slot);
		break;

	default:
		err("Illegal value specified for power\n");
		retval = -EINVAL;
	}
	module_put(slot->owner);

exit:
	if (retval)
		return retval;
	return count;
}

static struct pci_slot_attribute hotplug_slot_attr_power = {
	.attr = {.name = "power", .mode = S_IFREG | S_IRUGO | S_IWUSR},
	.show = power_read_file,
	.store = power_write_file
};

static ssize_t attention_read_file(struct pci_slot *pci_slot, char *buf)
{
	int retval;
	u8 value;

	retval = get_attention_status(pci_slot->hotplug, &value);
	if (retval)
		return retval;

	return sprintf(buf, "%d\n", value);
}

static ssize_t attention_write_file(struct pci_slot *pci_slot, const char *buf,
				    size_t count)
{
	struct hotplug_slot *slot = pci_slot->hotplug;
	const struct hotplug_slot_ops *ops = slot->ops;
	unsigned long lattention;
	u8 attention;
	int retval = 0;

	lattention = simple_strtoul(buf, NULL, 10);
	attention = (u8)(lattention & 0xff);
	dbg(" - attention = %d\n", attention);

	if (!try_module_get(slot->owner)) {
		retval = -ENODEV;
		goto exit;
	}
	if (ops->set_attention_status)
		retval = ops->set_attention_status(slot, attention);
	module_put(slot->owner);

exit:
	if (retval)
		return retval;
	return count;
}

static struct pci_slot_attribute hotplug_slot_attr_attention = {
	.attr = {.name = "attention", .mode = S_IFREG | S_IRUGO | S_IWUSR},
	.show = attention_read_file,
	.store = attention_write_file
};

static ssize_t latch_read_file(struct pci_slot *pci_slot, char *buf)
{
	int retval;
	u8 value;

	retval = get_latch_status(pci_slot->hotplug, &value);
	if (retval)
		return retval;

	return sprintf(buf, "%d\n", value);
}

static struct pci_slot_attribute hotplug_slot_attr_latch = {
	.attr = {.name = "latch", .mode = S_IFREG | S_IRUGO},
	.show = latch_read_file,
};

static ssize_t presence_read_file(struct pci_slot *pci_slot, char *buf)
{
	int retval;
	u8 value;

	retval = get_adapter_status(pci_slot->hotplug, &value);
	if (retval)
		return retval;

	return sprintf(buf, "%d\n", value);
}

static struct pci_slot_attribute hotplug_slot_attr_presence = {
	.attr = {.name = "adapter", .mode = S_IFREG | S_IRUGO},
	.show = presence_read_file,
};

static ssize_t test_write_file(struct pci_slot *pci_slot, const char *buf,
			       size_t count)
{
	struct hotplug_slot *slot = pci_slot->hotplug;
	unsigned long ltest;
	u32 test;
	int retval = 0;

	ltest = simple_strtoul(buf, NULL, 10);
	test = (u32)(ltest & 0xffffffff);
	dbg("test = %d\n", test);

	if (!try_module_get(slot->owner)) {
		retval = -ENODEV;
		goto exit;
	}
	if (slot->ops->hardware_test)
		retval = slot->ops->hardware_test(slot, test);
	module_put(slot->owner);

exit:
	if (retval)
		return retval;
	return count;
}

static struct pci_slot_attribute hotplug_slot_attr_test = {
	.attr = {.name = "test", .mode = S_IFREG | S_IRUGO | S_IWUSR},
	.store = test_write_file
};

static bool has_power_file(struct pci_slot *pci_slot)
{
	struct hotplug_slot *slot = pci_slot->hotplug;

	if ((!slot) || (!slot->ops))
		return false;
	if ((slot->ops->enable_slot) ||
	    (slot->ops->disable_slot) ||
	    (slot->ops->get_power_status))
		return true;
	return false;
}

static bool has_attention_file(struct pci_slot *pci_slot)
{
	struct hotplug_slot *slot = pci_slot->hotplug;

	if ((!slot) || (!slot->ops))
		return false;
	if ((slot->ops->set_attention_status) ||
	    (slot->ops->get_attention_status))
		return true;
	return false;
}

static bool has_latch_file(struct pci_slot *pci_slot)
{
	struct hotplug_slot *slot = pci_slot->hotplug;

	if ((!slot) || (!slot->ops))
		return false;
	if (slot->ops->get_latch_status)
		return true;
	return false;
}

static bool has_adapter_file(struct pci_slot *pci_slot)
{
	struct hotplug_slot *slot = pci_slot->hotplug;

	if ((!slot) || (!slot->ops))
		return false;
	if (slot->ops->get_adapter_status)
		return true;
	return false;
}

static bool has_test_file(struct pci_slot *pci_slot)
{
	struct hotplug_slot *slot = pci_slot->hotplug;

	if ((!slot) || (!slot->ops))
		return false;
	if (slot->ops->hardware_test)
		return true;
	return false;
}

static int fs_add_slot(struct pci_slot *pci_slot)
{
	int retval = 0;

	/* Create symbolic link to the hotplug driver module */
	pci_hp_create_module_link(pci_slot);

	if (has_power_file(pci_slot)) {
		retval = sysfs_create_file(&pci_slot->kobj,
					   &hotplug_slot_attr_power.attr);
		if (retval)
			goto exit_power;
	}

	if (has_attention_file(pci_slot)) {
		retval = sysfs_create_file(&pci_slot->kobj,
					   &hotplug_slot_attr_attention.attr);
		if (retval)
			goto exit_attention;
	}

	if (has_latch_file(pci_slot)) {
		retval = sysfs_create_file(&pci_slot->kobj,
					   &hotplug_slot_attr_latch.attr);
		if (retval)
			goto exit_latch;
	}

	if (has_adapter_file(pci_slot)) {
		retval = sysfs_create_file(&pci_slot->kobj,
					   &hotplug_slot_attr_presence.attr);
		if (retval)
			goto exit_adapter;
	}

	if (has_test_file(pci_slot)) {
		retval = sysfs_create_file(&pci_slot->kobj,
					   &hotplug_slot_attr_test.attr);
		if (retval)
			goto exit_test;
	}

	goto exit;

exit_test:
	if (has_adapter_file(pci_slot))
		sysfs_remove_file(&pci_slot->kobj,
				  &hotplug_slot_attr_presence.attr);
exit_adapter:
	if (has_latch_file(pci_slot))
		sysfs_remove_file(&pci_slot->kobj, &hotplug_slot_attr_latch.attr);
exit_latch:
	if (has_attention_file(pci_slot))
		sysfs_remove_file(&pci_slot->kobj,
				  &hotplug_slot_attr_attention.attr);
exit_attention:
	if (has_power_file(pci_slot))
		sysfs_remove_file(&pci_slot->kobj, &hotplug_slot_attr_power.attr);
exit_power:
	pci_hp_remove_module_link(pci_slot);
exit:
	return retval;
}

static void fs_remove_slot(struct pci_slot *pci_slot)
{
	if (has_power_file(pci_slot))
		sysfs_remove_file(&pci_slot->kobj, &hotplug_slot_attr_power.attr);

	if (has_attention_file(pci_slot))
		sysfs_remove_file(&pci_slot->kobj,
				  &hotplug_slot_attr_attention.attr);

	if (has_latch_file(pci_slot))
		sysfs_remove_file(&pci_slot->kobj, &hotplug_slot_attr_latch.attr);

	if (has_adapter_file(pci_slot))
		sysfs_remove_file(&pci_slot->kobj,
				  &hotplug_slot_attr_presence.attr);

	if (has_test_file(pci_slot))
		sysfs_remove_file(&pci_slot->kobj, &hotplug_slot_attr_test.attr);

	pci_hp_remove_module_link(pci_slot);
}

static struct hotplug_slot *get_slot_from_name(const char *name)
{
	struct hotplug_slot *slot;

	list_for_each_entry(slot, &pci_hotplug_slot_list, slot_list) {
		if (strcmp(hotplug_slot_name(slot), name) == 0)
			return slot;
	}
	return NULL;
}

/**
 * __pci_hp_register - register a hotplug_slot with the PCI hotplug subsystem
 * @bus: bus this slot is on
 * @slot: pointer to the &struct hotplug_slot to register
 * @devnr: device number
 * @name: name registered with kobject core
 * @owner: caller module owner
 * @mod_name: caller module name
 *
 * Prepares a hotplug slot for in-kernel use and immediately publishes it to
 * user space in one go.  Drivers may alternatively carry out the two steps
 * separately by invoking pci_hp_initialize() and pci_hp_add().
 *
 * Returns 0 if successful, anything else for an error.
 */
int __pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus,
		      int devnr, const char *name,
		      struct module *owner, const char *mod_name)
{
	int result;

	result = __pci_hp_initialize(slot, bus, devnr, name, owner, mod_name);
	if (result)
		return result;

	result = pci_hp_add(slot);
	if (result)
		pci_hp_destroy(slot);

	return result;
}
EXPORT_SYMBOL_GPL(__pci_hp_register);

/**
 * __pci_hp_initialize - prepare hotplug slot for in-kernel use
 * @slot: pointer to the &struct hotplug_slot to initialize
 * @bus: bus this slot is on
 * @devnr: slot number
 * @name: name registered with kobject core
 * @owner: caller module owner
 * @mod_name: caller module name
 *
 * Allocate and fill in a PCI slot for use by a hotplug driver.  Once this has
 * been called, the driver may invoke hotplug_slot_name() to get the slot's
 * unique name.  The driver must be prepared to handle a ->reset_slot callback
 * from this point on.
 *
 * Returns 0 on success or a negative int on error.
 */
int __pci_hp_initialize(struct hotplug_slot *slot, struct pci_bus *bus,
			int devnr, const char *name, struct module *owner,
			const char *mod_name)
{
	struct pci_slot *pci_slot;

	if (slot == NULL)
		return -ENODEV;
	if (slot->ops == NULL)
		return -EINVAL;

	slot->owner = owner;
	slot->mod_name = mod_name;

	/*
	 * No problems if we call this interface from both ACPI_PCI_SLOT
	 * driver and call it here again. If we've already created the
	 * pci_slot, the interface will simply bump the refcount.
	 */
	pci_slot = pci_create_slot(bus, devnr, name, slot);
	if (IS_ERR(pci_slot))
		return PTR_ERR(pci_slot);

	slot->pci_slot = pci_slot;
	pci_slot->hotplug = slot;
	return 0;
}
EXPORT_SYMBOL_GPL(__pci_hp_initialize);

/**
 * pci_hp_add - publish hotplug slot to user space
 * @slot: pointer to the &struct hotplug_slot to publish
 *
 * Make a hotplug slot's sysfs interface available and inform user space of its
 * addition by sending a uevent.  The hotplug driver must be prepared to handle
 * all &struct hotplug_slot_ops callbacks from this point on.
 *
 * Returns 0 on success or a negative int on error.
 */
int pci_hp_add(struct hotplug_slot *slot)
{
	struct pci_slot *pci_slot = slot->pci_slot;
	int result;

	result = fs_add_slot(pci_slot);
	if (result)
		return result;

	kobject_uevent(&pci_slot->kobj, KOBJ_ADD);
	mutex_lock(&pci_hp_mutex);
	list_add(&slot->slot_list, &pci_hotplug_slot_list);
	mutex_unlock(&pci_hp_mutex);
	dbg("Added slot %s to the list\n", hotplug_slot_name(slot));
	return 0;
}
EXPORT_SYMBOL_GPL(pci_hp_add);

/**
 * pci_hp_deregister - deregister a hotplug_slot with the PCI hotplug subsystem
 * @slot: pointer to the &struct hotplug_slot to deregister
 *
 * The @slot must have been registered with the pci hotplug subsystem
 * previously with a call to pci_hp_register().
 *
 * Returns 0 if successful, anything else for an error.
 */
void pci_hp_deregister(struct hotplug_slot *slot)
{
	pci_hp_del(slot);
	pci_hp_destroy(slot);
}
EXPORT_SYMBOL_GPL(pci_hp_deregister);

/**
 * pci_hp_del - unpublish hotplug slot from user space
 * @slot: pointer to the &struct hotplug_slot to unpublish
 *
 * Remove a hotplug slot's sysfs interface.
 *
 * Returns 0 on success or a negative int on error.
 */
void pci_hp_del(struct hotplug_slot *slot)
{
	struct hotplug_slot *temp;

	if (WARN_ON(!slot))
		return;

	mutex_lock(&pci_hp_mutex);
	temp = get_slot_from_name(hotplug_slot_name(slot));
	if (WARN_ON(temp != slot)) {
		mutex_unlock(&pci_hp_mutex);
		return;
	}

	list_del(&slot->slot_list);
	mutex_unlock(&pci_hp_mutex);
	dbg("Removed slot %s from the list\n", hotplug_slot_name(slot));
	fs_remove_slot(slot->pci_slot);
}
EXPORT_SYMBOL_GPL(pci_hp_del);

/**
 * pci_hp_destroy - remove hotplug slot from in-kernel use
 * @slot: pointer to the &struct hotplug_slot to destroy
 *
 * Destroy a PCI slot used by a hotplug driver.  Once this has been called,
 * the driver may no longer invoke hotplug_slot_name() to get the slot's
 * unique name.  The driver no longer needs to handle a ->reset_slot callback
 * from this point on.
 *
 * Returns 0 on success or a negative int on error.
 */
void pci_hp_destroy(struct hotplug_slot *slot)
{
	struct pci_slot *pci_slot = slot->pci_slot;

	slot->pci_slot = NULL;
	pci_slot->hotplug = NULL;
	pci_destroy_slot(pci_slot);
}
EXPORT_SYMBOL_GPL(pci_hp_destroy);

static int __init pci_hotplug_init(void)
{
	int result;

	result = cpci_hotplug_init(debug);
	if (result) {
		err("cpci_hotplug_init with error %d\n", result);
		return result;
	}

	return result;
}
device_initcall(pci_hotplug_init);

/*
 * not really modular, but the easiest way to keep compat with existing
 * bootargs behaviour is to continue using module_param here.
 */
module_param(debug, bool, 0644);
MODULE_PARM_DESC(debug, "Debugging mode enabled or not");