summaryrefslogtreecommitdiffstats
path: root/drivers/char/tpm/st33zp24/st33zp24.c
blob: a5b554cd477861ffa46d09aec45469ee35438e3a (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * STMicroelectronics TPM Linux driver for TPM ST33ZP24
 * Copyright (C) 2009 - 2016 STMicroelectronics
 */

#include <linux/acpi.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/wait.h>
#include <linux/freezer.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/gpio/consumer.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/slab.h>

#include "../tpm.h"
#include "st33zp24.h"

#define TPM_ACCESS			0x0
#define TPM_STS				0x18
#define TPM_DATA_FIFO			0x24
#define TPM_INTF_CAPABILITY		0x14
#define TPM_INT_STATUS			0x10
#define TPM_INT_ENABLE			0x08

#define LOCALITY0			0

enum st33zp24_access {
	TPM_ACCESS_VALID = 0x80,
	TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
	TPM_ACCESS_REQUEST_PENDING = 0x04,
	TPM_ACCESS_REQUEST_USE = 0x02,
};

enum st33zp24_status {
	TPM_STS_VALID = 0x80,
	TPM_STS_COMMAND_READY = 0x40,
	TPM_STS_GO = 0x20,
	TPM_STS_DATA_AVAIL = 0x10,
	TPM_STS_DATA_EXPECT = 0x08,
};

enum st33zp24_int_flags {
	TPM_GLOBAL_INT_ENABLE = 0x80,
	TPM_INTF_CMD_READY_INT = 0x080,
	TPM_INTF_FIFO_AVALAIBLE_INT = 0x040,
	TPM_INTF_WAKE_UP_READY_INT = 0x020,
	TPM_INTF_LOCALITY_CHANGE_INT = 0x004,
	TPM_INTF_STS_VALID_INT = 0x002,
	TPM_INTF_DATA_AVAIL_INT = 0x001,
};

enum tis_defaults {
	TIS_SHORT_TIMEOUT = 750,
	TIS_LONG_TIMEOUT = 2000,
};

/*
 * clear the pending interrupt.
 */
static u8 clear_interruption(struct st33zp24_dev *tpm_dev)
{
	u8 interrupt;

	tpm_dev->ops->recv(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
	tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
	return interrupt;
}

/*
 * cancel the current command execution or set STS to COMMAND READY.
 */
static void st33zp24_cancel(struct tpm_chip *chip)
{
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
	u8 data;

	data = TPM_STS_COMMAND_READY;
	tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
}

/*
 * return the TPM_STS register
 */
static u8 st33zp24_status(struct tpm_chip *chip)
{
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
	u8 data;

	tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS, &data, 1);
	return data;
}

/*
 * if the locality is active
 */
static bool check_locality(struct tpm_chip *chip)
{
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
	u8 data;
	u8 status;

	status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
	if (status && (data &
		(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
		(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
		return true;

	return false;
}

static int request_locality(struct tpm_chip *chip)
{
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
	unsigned long stop;
	long ret;
	u8 data;

	if (check_locality(chip))
		return tpm_dev->locality;

	data = TPM_ACCESS_REQUEST_USE;
	ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
	if (ret < 0)
		return ret;

	stop = jiffies + chip->timeout_a;

	/* Request locality is usually effective after the request */
	do {
		if (check_locality(chip))
			return tpm_dev->locality;
		msleep(TPM_TIMEOUT);
	} while (time_before(jiffies, stop));

	/* could not get locality */
	return -EACCES;
}

static void release_locality(struct tpm_chip *chip)
{
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
	u8 data;

	data = TPM_ACCESS_ACTIVE_LOCALITY;

	tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
}

/*
 * get_burstcount return the burstcount value
 */
static int get_burstcount(struct tpm_chip *chip)
{
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
	unsigned long stop;
	int burstcnt, status;
	u8 temp;

	stop = jiffies + chip->timeout_d;
	do {
		status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS + 1,
					    &temp, 1);
		if (status < 0)
			return -EBUSY;

		burstcnt = temp;
		status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS + 2,
					    &temp, 1);
		if (status < 0)
			return -EBUSY;

		burstcnt |= temp << 8;
		if (burstcnt)
			return burstcnt;
		msleep(TPM_TIMEOUT);
	} while (time_before(jiffies, stop));
	return -EBUSY;
}

static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
				bool check_cancel, bool *canceled)
{
	u8 status = chip->ops->status(chip);

	*canceled = false;
	if ((status & mask) == mask)
		return true;
	if (check_cancel && chip->ops->req_canceled(chip, status)) {
		*canceled = true;
		return true;
	}
	return false;
}

/*
 * wait for a TPM_STS value
 */
static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
			wait_queue_head_t *queue, bool check_cancel)
{
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
	unsigned long stop;
	int ret = 0;
	bool canceled = false;
	bool condition;
	u32 cur_intrs;
	u8 status;

	/* check current status */
	status = st33zp24_status(chip);
	if ((status & mask) == mask)
		return 0;

	stop = jiffies + timeout;

	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
		cur_intrs = tpm_dev->intrs;
		clear_interruption(tpm_dev);
		enable_irq(tpm_dev->irq);

		do {
			if (ret == -ERESTARTSYS && freezing(current))
				clear_thread_flag(TIF_SIGPENDING);

			timeout = stop - jiffies;
			if ((long) timeout <= 0)
				return -1;

			ret = wait_event_interruptible_timeout(*queue,
						cur_intrs != tpm_dev->intrs,
						timeout);
			clear_interruption(tpm_dev);
			condition = wait_for_tpm_stat_cond(chip, mask,
						check_cancel, &canceled);
			if (ret >= 0 && condition) {
				if (canceled)
					return -ECANCELED;
				return 0;
			}
		} while (ret == -ERESTARTSYS && freezing(current));

		disable_irq_nosync(tpm_dev->irq);

	} else {
		do {
			msleep(TPM_TIMEOUT);
			status = chip->ops->status(chip);
			if ((status & mask) == mask)
				return 0;
		} while (time_before(jiffies, stop));
	}

	return -ETIME;
}

static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
{
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
	int size = 0, burstcnt, len, ret;

	while (size < count &&
	       wait_for_stat(chip,
			     TPM_STS_DATA_AVAIL | TPM_STS_VALID,
			     chip->timeout_c,
			     &tpm_dev->read_queue, true) == 0) {
		burstcnt = get_burstcount(chip);
		if (burstcnt < 0)
			return burstcnt;
		len = min_t(int, burstcnt, count - size);
		ret = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_DATA_FIFO,
					 buf + size, len);
		if (ret < 0)
			return ret;

		size += len;
	}
	return size;
}

static irqreturn_t tpm_ioserirq_handler(int irq, void *dev_id)
{
	struct tpm_chip *chip = dev_id;
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);

	tpm_dev->intrs++;
	wake_up_interruptible(&tpm_dev->read_queue);
	disable_irq_nosync(tpm_dev->irq);

	return IRQ_HANDLED;
}

/*
 * send TPM commands through the I2C bus.
 */
static int st33zp24_send(struct tpm_chip *chip, unsigned char *buf,
			 size_t len)
{
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
	u32 status, i, size, ordinal;
	int burstcnt = 0;
	int ret;
	u8 data;

	if (len < TPM_HEADER_SIZE)
		return -EBUSY;

	ret = request_locality(chip);
	if (ret < 0)
		return ret;

	status = st33zp24_status(chip);
	if ((status & TPM_STS_COMMAND_READY) == 0) {
		st33zp24_cancel(chip);
		if (wait_for_stat
		    (chip, TPM_STS_COMMAND_READY, chip->timeout_b,
		     &tpm_dev->read_queue, false) < 0) {
			ret = -ETIME;
			goto out_err;
		}
	}

	for (i = 0; i < len - 1;) {
		burstcnt = get_burstcount(chip);
		if (burstcnt < 0)
			return burstcnt;
		size = min_t(int, len - i - 1, burstcnt);
		ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
					 buf + i, size);
		if (ret < 0)
			goto out_err;

		i += size;
	}

	status = st33zp24_status(chip);
	if ((status & TPM_STS_DATA_EXPECT) == 0) {
		ret = -EIO;
		goto out_err;
	}

	ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
				 buf + len - 1, 1);
	if (ret < 0)
		goto out_err;

	status = st33zp24_status(chip);
	if ((status & TPM_STS_DATA_EXPECT) != 0) {
		ret = -EIO;
		goto out_err;
	}

	data = TPM_STS_GO;
	ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
	if (ret < 0)
		goto out_err;

	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
		ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));

		ret = wait_for_stat(chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
				tpm_calc_ordinal_duration(chip, ordinal),
				&tpm_dev->read_queue, false);
		if (ret < 0)
			goto out_err;
	}

	return 0;
out_err:
	st33zp24_cancel(chip);
	release_locality(chip);
	return ret;
}

static int st33zp24_recv(struct tpm_chip *chip, unsigned char *buf,
			    size_t count)
{
	int size = 0;
	u32 expected;

	if (!chip)
		return -EBUSY;

	if (count < TPM_HEADER_SIZE) {
		size = -EIO;
		goto out;
	}

	size = recv_data(chip, buf, TPM_HEADER_SIZE);
	if (size < TPM_HEADER_SIZE) {
		dev_err(&chip->dev, "Unable to read header\n");
		goto out;
	}

	expected = be32_to_cpu(*(__be32 *)(buf + 2));
	if (expected > count || expected < TPM_HEADER_SIZE) {
		size = -EIO;
		goto out;
	}

	size += recv_data(chip, &buf[TPM_HEADER_SIZE],
			expected - TPM_HEADER_SIZE);
	if (size < expected) {
		dev_err(&chip->dev, "Unable to read remainder of result\n");
		size = -ETIME;
	}

out:
	st33zp24_cancel(chip);
	release_locality(chip);
	return size;
}

static bool st33zp24_req_canceled(struct tpm_chip *chip, u8 status)
{
	return (status == TPM_STS_COMMAND_READY);
}

static const struct tpm_class_ops st33zp24_tpm = {
	.flags = TPM_OPS_AUTO_STARTUP,
	.send = st33zp24_send,
	.recv = st33zp24_recv,
	.cancel = st33zp24_cancel,
	.status = st33zp24_status,
	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
	.req_canceled = st33zp24_req_canceled,
};

static const struct acpi_gpio_params lpcpd_gpios = { 1, 0, false };

static const struct acpi_gpio_mapping acpi_st33zp24_gpios[] = {
	{ "lpcpd-gpios", &lpcpd_gpios, 1 },
	{ },
};

/*
 * initialize the TPM device
 */
int st33zp24_probe(void *phy_id, const struct st33zp24_phy_ops *ops,
		   struct device *dev, int irq)
{
	int ret;
	u8 intmask = 0;
	struct tpm_chip *chip;
	struct st33zp24_dev *tpm_dev;

	chip = tpmm_chip_alloc(dev, &st33zp24_tpm);
	if (IS_ERR(chip))
		return PTR_ERR(chip);

	tpm_dev = devm_kzalloc(dev, sizeof(struct st33zp24_dev),
			       GFP_KERNEL);
	if (!tpm_dev)
		return -ENOMEM;

	tpm_dev->phy_id = phy_id;
	tpm_dev->ops = ops;
	dev_set_drvdata(&chip->dev, tpm_dev);

	chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
	chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
	chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
	chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);

	tpm_dev->locality = LOCALITY0;

	if (ACPI_COMPANION(dev)) {
		ret = devm_acpi_dev_add_driver_gpios(dev, acpi_st33zp24_gpios);
		if (ret)
			return ret;
	}

	/*
	 * Get LPCPD GPIO. If lpcpd pin is not specified. This is not an
	 * issue as power management can be also managed by TPM specific
	 * commands.
	 */
	tpm_dev->io_lpcpd = devm_gpiod_get_optional(dev, "lpcpd",
						    GPIOD_OUT_HIGH);
	ret = PTR_ERR_OR_ZERO(tpm_dev->io_lpcpd);
	if (ret) {
		dev_err(dev, "failed to request lpcpd gpio: %d\n", ret);
		return ret;
	}

	if (irq) {
		/* INTERRUPT Setup */
		init_waitqueue_head(&tpm_dev->read_queue);
		tpm_dev->intrs = 0;

		if (request_locality(chip) != LOCALITY0) {
			ret = -ENODEV;
			goto _tpm_clean_answer;
		}

		clear_interruption(tpm_dev);
		ret = devm_request_irq(dev, irq, tpm_ioserirq_handler,
				IRQF_TRIGGER_HIGH, "TPM SERIRQ management",
				chip);
		if (ret < 0) {
			dev_err(&chip->dev, "TPM SERIRQ signals %d not available\n",
				irq);
			goto _tpm_clean_answer;
		}

		intmask |= TPM_INTF_CMD_READY_INT
			|  TPM_INTF_STS_VALID_INT
			|  TPM_INTF_DATA_AVAIL_INT;

		ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_ENABLE,
					 &intmask, 1);
		if (ret < 0)
			goto _tpm_clean_answer;

		intmask = TPM_GLOBAL_INT_ENABLE;
		ret = tpm_dev->ops->send(tpm_dev->phy_id, (TPM_INT_ENABLE + 3),
					 &intmask, 1);
		if (ret < 0)
			goto _tpm_clean_answer;

		tpm_dev->irq = irq;
		chip->flags |= TPM_CHIP_FLAG_IRQ;

		disable_irq_nosync(tpm_dev->irq);
	}

	return tpm_chip_register(chip);
_tpm_clean_answer:
	dev_info(&chip->dev, "TPM initialization fail\n");
	return ret;
}
EXPORT_SYMBOL(st33zp24_probe);

void st33zp24_remove(struct tpm_chip *chip)
{
	tpm_chip_unregister(chip);
}
EXPORT_SYMBOL(st33zp24_remove);

#ifdef CONFIG_PM_SLEEP
int st33zp24_pm_suspend(struct device *dev)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);

	int ret = 0;

	if (tpm_dev->io_lpcpd)
		gpiod_set_value_cansleep(tpm_dev->io_lpcpd, 0);
	else
		ret = tpm_pm_suspend(dev);

	return ret;
}
EXPORT_SYMBOL(st33zp24_pm_suspend);

int st33zp24_pm_resume(struct device *dev)
{
	struct tpm_chip *chip = dev_get_drvdata(dev);
	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
	int ret = 0;

	if (tpm_dev->io_lpcpd) {
		gpiod_set_value_cansleep(tpm_dev->io_lpcpd, 1);
		ret = wait_for_stat(chip,
				TPM_STS_VALID, chip->timeout_b,
				&tpm_dev->read_queue, false);
	} else {
		ret = tpm_pm_resume(dev);
		if (!ret)
			tpm1_do_selftest(chip);
	}
	return ret;
}
EXPORT_SYMBOL(st33zp24_pm_resume);
#endif

MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
MODULE_DESCRIPTION("ST33ZP24 TPM 1.2 driver");
MODULE_VERSION("1.3.0");
MODULE_LICENSE("GPL");