summaryrefslogtreecommitdiff
path: root/drivers/firmware/dmi-sysfs.c
blob: d5de6ee8466d51532d041ae5ff9b07dfd2d03ca5 (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
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
/*
 * dmi-sysfs.c
 *
 * This module exports the DMI tables read-only to userspace through the
 * sysfs file system.
 *
 * Data is currently found below
 *    /sys/firmware/dmi/...
 *
 * DMI attributes are presented in attribute files with names
 * formatted using %d-%d, so that the first integer indicates the
 * structure type (0-255), and the second field is the instance of that
 * entry.
 *
 * Copyright 2011 Google, Inc.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kobject.h>
#include <linux/dmi.h>
#include <linux/capability.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/io.h>
#include <asm/dmi.h>

#define MAX_ENTRY_TYPE 255 /* Most of these aren't used, but we consider
			      the top entry type is only 8 bits */

struct dmi_sysfs_entry {
	struct dmi_header dh;
	struct kobject kobj;
	int instance;
	int position;
	struct list_head list;
	struct kobject *child;
};

/*
 * Global list of dmi_sysfs_entry.  Even though this should only be
 * manipulated at setup and teardown, the lazy nature of the kobject
 * system means we get lazy removes.
 */
static LIST_HEAD(entry_list);
static DEFINE_SPINLOCK(entry_list_lock);

/* dmi_sysfs_attribute - Top level attribute. used by all entries. */
struct dmi_sysfs_attribute {
	struct attribute attr;
	ssize_t (*show)(struct dmi_sysfs_entry *entry, char *buf);
};

#define DMI_SYSFS_ATTR(_entry, _name) \
struct dmi_sysfs_attribute dmi_sysfs_attr_##_entry##_##_name = { \
	.attr = {.name = __stringify(_name), .mode = 0400}, \
	.show = dmi_sysfs_##_entry##_##_name, \
}

/*
 * dmi_sysfs_mapped_attribute - Attribute where we require the entry be
 * mapped in.  Use in conjunction with dmi_sysfs_specialize_attr_ops.
 */
struct dmi_sysfs_mapped_attribute {
	struct attribute attr;
	ssize_t (*show)(struct dmi_sysfs_entry *entry,
			const struct dmi_header *dh,
			char *buf);
};

#define DMI_SYSFS_MAPPED_ATTR(_entry, _name) \
struct dmi_sysfs_mapped_attribute dmi_sysfs_attr_##_entry##_##_name = { \
	.attr = {.name = __stringify(_name), .mode = 0400}, \
	.show = dmi_sysfs_##_entry##_##_name, \
}

/*************************************************
 * Generic DMI entry support.
 *************************************************/
static void dmi_entry_free(struct kobject *kobj)
{
	kfree(kobj);
}

static struct dmi_sysfs_entry *to_entry(struct kobject *kobj)
{
	return container_of(kobj, struct dmi_sysfs_entry, kobj);
}

static struct dmi_sysfs_attribute *to_attr(struct attribute *attr)
{
	return container_of(attr, struct dmi_sysfs_attribute, attr);
}

static ssize_t dmi_sysfs_attr_show(struct kobject *kobj,
				   struct attribute *_attr, char *buf)
{
	struct dmi_sysfs_entry *entry = to_entry(kobj);
	struct dmi_sysfs_attribute *attr = to_attr(_attr);

	/* DMI stuff is only ever admin visible */
	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	return attr->show(entry, buf);
}

static const struct sysfs_ops dmi_sysfs_attr_ops = {
	.show = dmi_sysfs_attr_show,
};

typedef ssize_t (*dmi_callback)(struct dmi_sysfs_entry *,
				const struct dmi_header *dh, void *);

struct find_dmi_data {
	struct dmi_sysfs_entry	*entry;
	dmi_callback		callback;
	void			*private;
	int			instance_countdown;
	ssize_t			ret;
};

static void find_dmi_entry_helper(const struct dmi_header *dh,
				  void *_data)
{
	struct find_dmi_data *data = _data;
	struct dmi_sysfs_entry *entry = data->entry;

	/* Is this the entry we want? */
	if (dh->type != entry->dh.type)
		return;

	if (data->instance_countdown != 0) {
		/* try the next instance? */
		data->instance_countdown--;
		return;
	}

	/*
	 * Don't ever revisit the instance.  Short circuit later
	 * instances by letting the instance_countdown run negative
	 */
	data->instance_countdown--;

	/* Found the entry */
	data->ret = data->callback(entry, dh, data->private);
}

/* State for passing the read parameters through dmi_find_entry() */
struct dmi_read_state {
	char *buf;
	loff_t pos;
	size_t count;
};

static ssize_t find_dmi_entry(struct dmi_sysfs_entry *entry,
			      dmi_callback callback, void *private)
{
	struct find_dmi_data data = {
		.entry = entry,
		.callback = callback,
		.private = private,
		.instance_countdown = entry->instance,
		.ret = -EIO,  /* To signal the entry disappeared */
	};
	int ret;

	ret = dmi_walk(find_dmi_entry_helper, &data);
	/* This shouldn't happen, but just in case. */
	if (ret)
		return -EINVAL;
	return data.ret;
}

/*
 * Calculate and return the byte length of the dmi entry identified by
 * dh.  This includes both the formatted portion as well as the
 * unformatted string space, including the two trailing nul characters.
 */
static size_t dmi_entry_length(const struct dmi_header *dh)
{
	const char *p = (const char *)dh;

	p += dh->length;

	while (p[0] || p[1])
		p++;

	return 2 + p - (const char *)dh;
}

/*************************************************
 * Support bits for specialized DMI entry support
 *************************************************/
struct dmi_entry_attr_show_data {
	struct attribute *attr;
	char *buf;
};

static ssize_t dmi_entry_attr_show_helper(struct dmi_sysfs_entry *entry,
					  const struct dmi_header *dh,
					  void *_data)
{
	struct dmi_entry_attr_show_data *data = _data;
	struct dmi_sysfs_mapped_attribute *attr;

	attr = container_of(data->attr,
			    struct dmi_sysfs_mapped_attribute, attr);
	return attr->show(entry, dh, data->buf);
}

static ssize_t dmi_entry_attr_show(struct kobject *kobj,
				   struct attribute *attr,
				   char *buf)
{
	struct dmi_entry_attr_show_data data = {
		.attr = attr,
		.buf  = buf,
	};
	/* Find the entry according to our parent and call the
	 * normalized show method hanging off of the attribute */
	return find_dmi_entry(to_entry(kobj->parent),
			      dmi_entry_attr_show_helper, &data);
}

static const struct sysfs_ops dmi_sysfs_specialize_attr_ops = {
	.show = dmi_entry_attr_show,
};

/*************************************************
 * Specialized DMI entry support.
 *************************************************/

/*** Type 15 - System Event Table ***/

#define DMI_SEL_ACCESS_METHOD_IO8	0x00
#define DMI_SEL_ACCESS_METHOD_IO2x8	0x01
#define DMI_SEL_ACCESS_METHOD_IO16	0x02
#define DMI_SEL_ACCESS_METHOD_PHYS32	0x03
#define DMI_SEL_ACCESS_METHOD_GPNV	0x04

struct dmi_system_event_log {
	struct dmi_header header;
	u16	area_length;
	u16	header_start_offset;
	u16	data_start_offset;
	u8	access_method;
	u8	status;
	u32	change_token;
	union {
		struct {
			u16 index_addr;
			u16 data_addr;
		} io;
		u32	phys_addr32;
		u16	gpnv_handle;
		u32	access_method_address;
	};
	u8	header_format;
	u8	type_descriptors_supported_count;
	u8	per_log_type_descriptor_length;
	u8	supported_log_type_descriptos[0];
} __packed;

#define DMI_SYSFS_SEL_FIELD(_field) \
static ssize_t dmi_sysfs_sel_##_field(struct dmi_sysfs_entry *entry, \
				      const struct dmi_header *dh, \
				      char *buf) \
{ \
	struct dmi_system_event_log sel; \
	if (sizeof(sel) > dmi_entry_length(dh)) \
		return -EIO; \
	memcpy(&sel, dh, sizeof(sel)); \
	return sprintf(buf, "%u\n", sel._field); \
} \
static DMI_SYSFS_MAPPED_ATTR(sel, _field)

DMI_SYSFS_SEL_FIELD(area_length);
DMI_SYSFS_SEL_FIELD(header_start_offset);
DMI_SYSFS_SEL_FIELD(data_start_offset);
DMI_SYSFS_SEL_FIELD(access_method);
DMI_SYSFS_SEL_FIELD(status);
DMI_SYSFS_SEL_FIELD(change_token);
DMI_SYSFS_SEL_FIELD(access_method_address);
DMI_SYSFS_SEL_FIELD(header_format);
DMI_SYSFS_SEL_FIELD(type_descriptors_supported_count);
DMI_SYSFS_SEL_FIELD(per_log_type_descriptor_length);

static struct attribute *dmi_sysfs_sel_attrs[] = {
	&dmi_sysfs_attr_sel_area_length.attr,
	&dmi_sysfs_attr_sel_header_start_offset.attr,
	&dmi_sysfs_attr_sel_data_start_offset.attr,
	&dmi_sysfs_attr_sel_access_method.attr,
	&dmi_sysfs_attr_sel_status.attr,
	&dmi_sysfs_attr_sel_change_token.attr,
	&dmi_sysfs_attr_sel_access_method_address.attr,
	&dmi_sysfs_attr_sel_header_format.attr,
	&dmi_sysfs_attr_sel_type_descriptors_supported_count.attr,
	&dmi_sysfs_attr_sel_per_log_type_descriptor_length.attr,
	NULL,
};


static struct kobj_type dmi_system_event_log_ktype = {
	.release = dmi_entry_free,
	.sysfs_ops = &dmi_sysfs_specialize_attr_ops,
	.default_attrs = dmi_sysfs_sel_attrs,
};

typedef u8 (*sel_io_reader)(const struct dmi_system_event_log *sel,
			    loff_t offset);

static DEFINE_MUTEX(io_port_lock);

static u8 read_sel_8bit_indexed_io(const struct dmi_system_event_log *sel,
				   loff_t offset)
{
	u8 ret;

	mutex_lock(&io_port_lock);
	outb((u8)offset, sel->io.index_addr);
	ret = inb(sel->io.data_addr);
	mutex_unlock(&io_port_lock);
	return ret;
}

static u8 read_sel_2x8bit_indexed_io(const struct dmi_system_event_log *sel,
				     loff_t offset)
{
	u8 ret;

	mutex_lock(&io_port_lock);
	outb((u8)offset, sel->io.index_addr);
	outb((u8)(offset >> 8), sel->io.index_addr + 1);
	ret = inb(sel->io.data_addr);
	mutex_unlock(&io_port_lock);
	return ret;
}

static u8 read_sel_16bit_indexed_io(const struct dmi_system_event_log *sel,
				    loff_t offset)
{
	u8 ret;

	mutex_lock(&io_port_lock);
	outw((u16)offset, sel->io.index_addr);
	ret = inb(sel->io.data_addr);
	mutex_unlock(&io_port_lock);
	return ret;
}

static sel_io_reader sel_io_readers[] = {
	[DMI_SEL_ACCESS_METHOD_IO8]	= read_sel_8bit_indexed_io,
	[DMI_SEL_ACCESS_METHOD_IO2x8]	= read_sel_2x8bit_indexed_io,
	[DMI_SEL_ACCESS_METHOD_IO16]	= read_sel_16bit_indexed_io,
};

static ssize_t dmi_sel_raw_read_io(struct dmi_sysfs_entry *entry,
				   const struct dmi_system_event_log *sel,
				   char *buf, loff_t pos, size_t count)
{
	ssize_t wrote = 0;

	sel_io_reader io_reader = sel_io_readers[sel->access_method];

	while (count && pos < sel->area_length) {
		count--;
		*(buf++) = io_reader(sel, pos++);
		wrote++;
	}

	return wrote;
}

static ssize_t dmi_sel_raw_read_phys32(struct dmi_sysfs_entry *entry,
				       const struct dmi_system_event_log *sel,
				       char *buf, loff_t pos, size_t count)
{
	u8 __iomem *mapped;
	ssize_t wrote = 0;

	mapped = dmi_remap(sel->access_method_address, sel->area_length);
	if (!mapped)
		return -EIO;

	while (count && pos < sel->area_length) {
		count--;
		*(buf++) = readb(mapped + pos++);
		wrote++;
	}

	dmi_unmap(mapped);
	return wrote;
}

static ssize_t dmi_sel_raw_read_helper(struct dmi_sysfs_entry *entry,
				       const struct dmi_header *dh,
				       void *_state)
{
	struct dmi_read_state *state = _state;
	struct dmi_system_event_log sel;

	if (sizeof(sel) > dmi_entry_length(dh))
		return -EIO;

	memcpy(&sel, dh, sizeof(sel));

	switch (sel.access_method) {
	case DMI_SEL_ACCESS_METHOD_IO8:
	case DMI_SEL_ACCESS_METHOD_IO2x8:
	case DMI_SEL_ACCESS_METHOD_IO16:
		return dmi_sel_raw_read_io(entry, &sel, state->buf,
					   state->pos, state->count);
	case DMI_SEL_ACCESS_METHOD_PHYS32:
		return dmi_sel_raw_read_phys32(entry, &sel, state->buf,
					       state->pos, state->count);
	case DMI_SEL_ACCESS_METHOD_GPNV:
		pr_info("dmi-sysfs: GPNV support missing.\n");
		return -EIO;
	default:
		pr_info("dmi-sysfs: Unknown access method %02x\n",
			sel.access_method);
		return -EIO;
	}
}

static ssize_t dmi_sel_raw_read(struct file *filp, struct kobject *kobj,
				struct bin_attribute *bin_attr,
				char *buf, loff_t pos, size_t count)
{
	struct dmi_sysfs_entry *entry = to_entry(kobj->parent);
	struct dmi_read_state state = {
		.buf = buf,
		.pos = pos,
		.count = count,
	};

	return find_dmi_entry(entry, dmi_sel_raw_read_helper, &state);
}

static struct bin_attribute dmi_sel_raw_attr = {
	.attr = {.name = "raw_event_log", .mode = 0400},
	.read = dmi_sel_raw_read,
};

static int dmi_system_event_log(struct dmi_sysfs_entry *entry)
{
	int ret;

	entry->child = kzalloc(sizeof(*entry->child), GFP_KERNEL);
	if (!entry->child)
		return -ENOMEM;
	ret = kobject_init_and_add(entry->child,
				   &dmi_system_event_log_ktype,
				   &entry->kobj,
				   "system_event_log");
	if (ret)
		goto out_free;

	ret = sysfs_create_bin_file(entry->child, &dmi_sel_raw_attr);
	if (ret)
		goto out_del;

	return 0;

out_del:
	kobject_del(entry->child);
out_free:
	kfree(entry->child);
	return ret;
}

/*************************************************
 * Generic DMI entry support.
 *************************************************/

static ssize_t dmi_sysfs_entry_length(struct dmi_sysfs_entry *entry, char *buf)
{
	return sprintf(buf, "%d\n", entry->dh.length);
}

static ssize_t dmi_sysfs_entry_handle(struct dmi_sysfs_entry *entry, char *buf)
{
	return sprintf(buf, "%d\n", entry->dh.handle);
}

static ssize_t dmi_sysfs_entry_type(struct dmi_sysfs_entry *entry, char *buf)
{
	return sprintf(buf, "%d\n", entry->dh.type);
}

static ssize_t dmi_sysfs_entry_instance(struct dmi_sysfs_entry *entry,
					char *buf)
{
	return sprintf(buf, "%d\n", entry->instance);
}

static ssize_t dmi_sysfs_entry_position(struct dmi_sysfs_entry *entry,
					char *buf)
{
	return sprintf(buf, "%d\n", entry->position);
}

static DMI_SYSFS_ATTR(entry, length);
static DMI_SYSFS_ATTR(entry, handle);
static DMI_SYSFS_ATTR(entry, type);
static DMI_SYSFS_ATTR(entry, instance);
static DMI_SYSFS_ATTR(entry, position);

static struct attribute *dmi_sysfs_entry_attrs[] = {
	&dmi_sysfs_attr_entry_length.attr,
	&dmi_sysfs_attr_entry_handle.attr,
	&dmi_sysfs_attr_entry_type.attr,
	&dmi_sysfs_attr_entry_instance.attr,
	&dmi_sysfs_attr_entry_position.attr,
	NULL,
};

static ssize_t dmi_entry_raw_read_helper(struct dmi_sysfs_entry *entry,
					 const struct dmi_header *dh,
					 void *_state)
{
	struct dmi_read_state *state = _state;
	size_t entry_length;

	entry_length = dmi_entry_length(dh);

	return memory_read_from_buffer(state->buf, state->count,
				       &state->pos, dh, entry_length);
}

static ssize_t dmi_entry_raw_read(struct file *filp,
				  struct kobject *kobj,
				  struct bin_attribute *bin_attr,
				  char *buf, loff_t pos, size_t count)
{
	struct dmi_sysfs_entry *entry = to_entry(kobj);
	struct dmi_read_state state = {
		.buf = buf,
		.pos = pos,
		.count = count,
	};

	return find_dmi_entry(entry, dmi_entry_raw_read_helper, &state);
}

static const struct bin_attribute dmi_entry_raw_attr = {
	.attr = {.name = "raw", .mode = 0400},
	.read = dmi_entry_raw_read,
};

static void dmi_sysfs_entry_release(struct kobject *kobj)
{
	struct dmi_sysfs_entry *entry = to_entry(kobj);

	spin_lock(&entry_list_lock);
	list_del(&entry->list);
	spin_unlock(&entry_list_lock);
	kfree(entry);
}

static struct kobj_type dmi_sysfs_entry_ktype = {
	.release = dmi_sysfs_entry_release,
	.sysfs_ops = &dmi_sysfs_attr_ops,
	.default_attrs = dmi_sysfs_entry_attrs,
};

static struct kset *dmi_kset;

/* Global count of all instances seen.  Only for setup */
static int __initdata instance_counts[MAX_ENTRY_TYPE + 1];

/* Global positional count of all entries seen.  Only for setup */
static int __initdata position_count;

static void __init dmi_sysfs_register_handle(const struct dmi_header *dh,
					     void *_ret)
{
	struct dmi_sysfs_entry *entry;
	int *ret = _ret;

	/* If a previous entry saw an error, short circuit */
	if (*ret)
		return;

	/* Allocate and register a new entry into the entries set */
	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	if (!entry) {
		*ret = -ENOMEM;
		return;
	}

	/* Set the key */
	memcpy(&entry->dh, dh, sizeof(*dh));
	entry->instance = instance_counts[dh->type]++;
	entry->position = position_count++;

	entry->kobj.kset = dmi_kset;
	*ret = kobject_init_and_add(&entry->kobj, &dmi_sysfs_entry_ktype, NULL,
				    "%d-%d", dh->type, entry->instance);

	if (*ret) {
		kfree(entry);
		return;
	}

	/* Thread on the global list for cleanup */
	spin_lock(&entry_list_lock);
	list_add_tail(&entry->list, &entry_list);
	spin_unlock(&entry_list_lock);

	/* Handle specializations by type */
	switch (dh->type) {
	case DMI_ENTRY_SYSTEM_EVENT_LOG:
		*ret = dmi_system_event_log(entry);
		break;
	default:
		/* No specialization */
		break;
	}
	if (*ret)
		goto out_err;

	/* Create the raw binary file to access the entry */
	*ret = sysfs_create_bin_file(&entry->kobj, &dmi_entry_raw_attr);
	if (*ret)
		goto out_err;

	return;
out_err:
	kobject_put(entry->child);
	kobject_put(&entry->kobj);
	return;
}

static void cleanup_entry_list(void)
{
	struct dmi_sysfs_entry *entry, *next;

	/* No locks, we are on our way out */
	list_for_each_entry_safe(entry, next, &entry_list, list) {
		kobject_put(entry->child);
		kobject_put(&entry->kobj);
	}
}

static int __init dmi_sysfs_init(void)
{
	int error;
	int val;

	if (!dmi_kobj) {
		pr_err("dmi-sysfs: dmi entry is absent.\n");
		error = -ENODATA;
		goto err;
	}

	dmi_kset = kset_create_and_add("entries", NULL, dmi_kobj);
	if (!dmi_kset) {
		error = -ENOMEM;
		goto err;
	}

	val = 0;
	error = dmi_walk(dmi_sysfs_register_handle, &val);
	if (error)
		goto err;
	if (val) {
		error = val;
		goto err;
	}

	pr_debug("dmi-sysfs: loaded.\n");

	return 0;
err:
	cleanup_entry_list();
	kset_unregister(dmi_kset);
	return error;
}

/* clean up everything. */
static void __exit dmi_sysfs_exit(void)
{
	pr_debug("dmi-sysfs: unloading.\n");
	cleanup_entry_list();
	kset_unregister(dmi_kset);
}

module_init(dmi_sysfs_init);
module_exit(dmi_sysfs_exit);

MODULE_AUTHOR("Mike Waychison <mikew@google.com>");
MODULE_DESCRIPTION("DMI sysfs support");
MODULE_LICENSE("GPL");