1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * STMicroelectronics TPM Linux driver for TPM ST33ZP24
4  * Copyright (C) 2009 - 2016 STMicroelectronics
5  */
6 
7 #include <linux/module.h>
8 #include <linux/fs.h>
9 #include <linux/kernel.h>
10 #include <linux/delay.h>
11 #include <linux/wait.h>
12 #include <linux/freezer.h>
13 #include <linux/string.h>
14 #include <linux/interrupt.h>
15 #include <linux/gpio.h>
16 #include <linux/sched.h>
17 #include <linux/uaccess.h>
18 #include <linux/io.h>
19 #include <linux/slab.h>
20 
21 #include "../tpm.h"
22 #include "st33zp24.h"
23 
24 #define TPM_ACCESS			0x0
25 #define TPM_STS				0x18
26 #define TPM_DATA_FIFO			0x24
27 #define TPM_INTF_CAPABILITY		0x14
28 #define TPM_INT_STATUS			0x10
29 #define TPM_INT_ENABLE			0x08
30 
31 #define LOCALITY0			0
32 
33 enum st33zp24_access {
34 	TPM_ACCESS_VALID = 0x80,
35 	TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
36 	TPM_ACCESS_REQUEST_PENDING = 0x04,
37 	TPM_ACCESS_REQUEST_USE = 0x02,
38 };
39 
40 enum st33zp24_status {
41 	TPM_STS_VALID = 0x80,
42 	TPM_STS_COMMAND_READY = 0x40,
43 	TPM_STS_GO = 0x20,
44 	TPM_STS_DATA_AVAIL = 0x10,
45 	TPM_STS_DATA_EXPECT = 0x08,
46 };
47 
48 enum st33zp24_int_flags {
49 	TPM_GLOBAL_INT_ENABLE = 0x80,
50 	TPM_INTF_CMD_READY_INT = 0x080,
51 	TPM_INTF_FIFO_AVALAIBLE_INT = 0x040,
52 	TPM_INTF_WAKE_UP_READY_INT = 0x020,
53 	TPM_INTF_LOCALITY_CHANGE_INT = 0x004,
54 	TPM_INTF_STS_VALID_INT = 0x002,
55 	TPM_INTF_DATA_AVAIL_INT = 0x001,
56 };
57 
58 enum tis_defaults {
59 	TIS_SHORT_TIMEOUT = 750,
60 	TIS_LONG_TIMEOUT = 2000,
61 };
62 
63 /*
64  * clear_interruption clear the pending interrupt.
65  * @param: tpm_dev, the tpm device device.
66  * @return: the interrupt status value.
67  */
68 static u8 clear_interruption(struct st33zp24_dev *tpm_dev)
69 {
70 	u8 interrupt;
71 
72 	tpm_dev->ops->recv(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
73 	tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_STATUS, &interrupt, 1);
74 	return interrupt;
75 } /* clear_interruption() */
76 
77 /*
78  * st33zp24_cancel, cancel the current command execution or
79  * set STS to COMMAND READY.
80  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
81  */
82 static void st33zp24_cancel(struct tpm_chip *chip)
83 {
84 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
85 	u8 data;
86 
87 	data = TPM_STS_COMMAND_READY;
88 	tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
89 } /* st33zp24_cancel() */
90 
91 /*
92  * st33zp24_status return the TPM_STS register
93  * @param: chip, the tpm chip description
94  * @return: the TPM_STS register value.
95  */
96 static u8 st33zp24_status(struct tpm_chip *chip)
97 {
98 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
99 	u8 data;
100 
101 	tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS, &data, 1);
102 	return data;
103 } /* st33zp24_status() */
104 
105 /*
106  * check_locality if the locality is active
107  * @param: chip, the tpm chip description
108  * @return: true if LOCALITY0 is active, otherwise false
109  */
110 static bool check_locality(struct tpm_chip *chip)
111 {
112 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
113 	u8 data;
114 	u8 status;
115 
116 	status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
117 	if (status && (data &
118 		(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
119 		(TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
120 		return true;
121 
122 	return false;
123 } /* check_locality() */
124 
125 /*
126  * request_locality request the TPM locality
127  * @param: chip, the chip description
128  * @return: the active locality or negative value.
129  */
130 static int request_locality(struct tpm_chip *chip)
131 {
132 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
133 	unsigned long stop;
134 	long ret;
135 	u8 data;
136 
137 	if (check_locality(chip))
138 		return tpm_dev->locality;
139 
140 	data = TPM_ACCESS_REQUEST_USE;
141 	ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
142 	if (ret < 0)
143 		return ret;
144 
145 	stop = jiffies + chip->timeout_a;
146 
147 	/* Request locality is usually effective after the request */
148 	do {
149 		if (check_locality(chip))
150 			return tpm_dev->locality;
151 		msleep(TPM_TIMEOUT);
152 	} while (time_before(jiffies, stop));
153 
154 	/* could not get locality */
155 	return -EACCES;
156 } /* request_locality() */
157 
158 /*
159  * release_locality release the active locality
160  * @param: chip, the tpm chip description.
161  */
162 static void release_locality(struct tpm_chip *chip)
163 {
164 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
165 	u8 data;
166 
167 	data = TPM_ACCESS_ACTIVE_LOCALITY;
168 
169 	tpm_dev->ops->send(tpm_dev->phy_id, TPM_ACCESS, &data, 1);
170 }
171 
172 /*
173  * get_burstcount return the burstcount value
174  * @param: chip, the chip description
175  * return: the burstcount or negative value.
176  */
177 static int get_burstcount(struct tpm_chip *chip)
178 {
179 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
180 	unsigned long stop;
181 	int burstcnt, status;
182 	u8 temp;
183 
184 	stop = jiffies + chip->timeout_d;
185 	do {
186 		status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS + 1,
187 					    &temp, 1);
188 		if (status < 0)
189 			return -EBUSY;
190 
191 		burstcnt = temp;
192 		status = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_STS + 2,
193 					    &temp, 1);
194 		if (status < 0)
195 			return -EBUSY;
196 
197 		burstcnt |= temp << 8;
198 		if (burstcnt)
199 			return burstcnt;
200 		msleep(TPM_TIMEOUT);
201 	} while (time_before(jiffies, stop));
202 	return -EBUSY;
203 } /* get_burstcount() */
204 
205 
206 /*
207  * wait_for_tpm_stat_cond
208  * @param: chip, chip description
209  * @param: mask, expected mask value
210  * @param: check_cancel, does the command expected to be canceled ?
211  * @param: canceled, did we received a cancel request ?
212  * @return: true if status == mask or if the command is canceled.
213  * false in other cases.
214  */
215 static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
216 				bool check_cancel, bool *canceled)
217 {
218 	u8 status = chip->ops->status(chip);
219 
220 	*canceled = false;
221 	if ((status & mask) == mask)
222 		return true;
223 	if (check_cancel && chip->ops->req_canceled(chip, status)) {
224 		*canceled = true;
225 		return true;
226 	}
227 	return false;
228 }
229 
230 /*
231  * wait_for_stat wait for a TPM_STS value
232  * @param: chip, the tpm chip description
233  * @param: mask, the value mask to wait
234  * @param: timeout, the timeout
235  * @param: queue, the wait queue.
236  * @param: check_cancel, does the command can be cancelled ?
237  * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
238  */
239 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
240 			wait_queue_head_t *queue, bool check_cancel)
241 {
242 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
243 	unsigned long stop;
244 	int ret = 0;
245 	bool canceled = false;
246 	bool condition;
247 	u32 cur_intrs;
248 	u8 status;
249 
250 	/* check current status */
251 	status = st33zp24_status(chip);
252 	if ((status & mask) == mask)
253 		return 0;
254 
255 	stop = jiffies + timeout;
256 
257 	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
258 		cur_intrs = tpm_dev->intrs;
259 		clear_interruption(tpm_dev);
260 		enable_irq(tpm_dev->irq);
261 
262 		do {
263 			if (ret == -ERESTARTSYS && freezing(current))
264 				clear_thread_flag(TIF_SIGPENDING);
265 
266 			timeout = stop - jiffies;
267 			if ((long) timeout <= 0)
268 				return -1;
269 
270 			ret = wait_event_interruptible_timeout(*queue,
271 						cur_intrs != tpm_dev->intrs,
272 						timeout);
273 			clear_interruption(tpm_dev);
274 			condition = wait_for_tpm_stat_cond(chip, mask,
275 						check_cancel, &canceled);
276 			if (ret >= 0 && condition) {
277 				if (canceled)
278 					return -ECANCELED;
279 				return 0;
280 			}
281 		} while (ret == -ERESTARTSYS && freezing(current));
282 
283 		disable_irq_nosync(tpm_dev->irq);
284 
285 	} else {
286 		do {
287 			msleep(TPM_TIMEOUT);
288 			status = chip->ops->status(chip);
289 			if ((status & mask) == mask)
290 				return 0;
291 		} while (time_before(jiffies, stop));
292 	}
293 
294 	return -ETIME;
295 } /* wait_for_stat() */
296 
297 /*
298  * recv_data receive data
299  * @param: chip, the tpm chip description
300  * @param: buf, the buffer where the data are received
301  * @param: count, the number of data to receive
302  * @return: the number of bytes read from TPM FIFO.
303  */
304 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
305 {
306 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
307 	int size = 0, burstcnt, len, ret;
308 
309 	while (size < count &&
310 	       wait_for_stat(chip,
311 			     TPM_STS_DATA_AVAIL | TPM_STS_VALID,
312 			     chip->timeout_c,
313 			     &tpm_dev->read_queue, true) == 0) {
314 		burstcnt = get_burstcount(chip);
315 		if (burstcnt < 0)
316 			return burstcnt;
317 		len = min_t(int, burstcnt, count - size);
318 		ret = tpm_dev->ops->recv(tpm_dev->phy_id, TPM_DATA_FIFO,
319 					 buf + size, len);
320 		if (ret < 0)
321 			return ret;
322 
323 		size += len;
324 	}
325 	return size;
326 }
327 
328 /*
329  * tpm_ioserirq_handler the serirq irq handler
330  * @param: irq, the tpm chip description
331  * @param: dev_id, the description of the chip
332  * @return: the status of the handler.
333  */
334 static irqreturn_t tpm_ioserirq_handler(int irq, void *dev_id)
335 {
336 	struct tpm_chip *chip = dev_id;
337 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
338 
339 	tpm_dev->intrs++;
340 	wake_up_interruptible(&tpm_dev->read_queue);
341 	disable_irq_nosync(tpm_dev->irq);
342 
343 	return IRQ_HANDLED;
344 } /* tpm_ioserirq_handler() */
345 
346 /*
347  * st33zp24_send send TPM commands through the I2C bus.
348  *
349  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h
350  * @param: buf,	the buffer to send.
351  * @param: count, the number of bytes to send.
352  * @return: In case of success the number of bytes sent.
353  *			In other case, a < 0 value describing the issue.
354  */
355 static int st33zp24_send(struct tpm_chip *chip, unsigned char *buf,
356 			 size_t len)
357 {
358 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
359 	u32 status, i, size, ordinal;
360 	int burstcnt = 0;
361 	int ret;
362 	u8 data;
363 
364 	if (len < TPM_HEADER_SIZE)
365 		return -EBUSY;
366 
367 	ret = request_locality(chip);
368 	if (ret < 0)
369 		return ret;
370 
371 	status = st33zp24_status(chip);
372 	if ((status & TPM_STS_COMMAND_READY) == 0) {
373 		st33zp24_cancel(chip);
374 		if (wait_for_stat
375 		    (chip, TPM_STS_COMMAND_READY, chip->timeout_b,
376 		     &tpm_dev->read_queue, false) < 0) {
377 			ret = -ETIME;
378 			goto out_err;
379 		}
380 	}
381 
382 	for (i = 0; i < len - 1;) {
383 		burstcnt = get_burstcount(chip);
384 		if (burstcnt < 0)
385 			return burstcnt;
386 		size = min_t(int, len - i - 1, burstcnt);
387 		ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
388 					 buf + i, size);
389 		if (ret < 0)
390 			goto out_err;
391 
392 		i += size;
393 	}
394 
395 	status = st33zp24_status(chip);
396 	if ((status & TPM_STS_DATA_EXPECT) == 0) {
397 		ret = -EIO;
398 		goto out_err;
399 	}
400 
401 	ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_DATA_FIFO,
402 				 buf + len - 1, 1);
403 	if (ret < 0)
404 		goto out_err;
405 
406 	status = st33zp24_status(chip);
407 	if ((status & TPM_STS_DATA_EXPECT) != 0) {
408 		ret = -EIO;
409 		goto out_err;
410 	}
411 
412 	data = TPM_STS_GO;
413 	ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_STS, &data, 1);
414 	if (ret < 0)
415 		goto out_err;
416 
417 	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
418 		ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
419 
420 		ret = wait_for_stat(chip, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
421 				tpm_calc_ordinal_duration(chip, ordinal),
422 				&tpm_dev->read_queue, false);
423 		if (ret < 0)
424 			goto out_err;
425 	}
426 
427 	return 0;
428 out_err:
429 	st33zp24_cancel(chip);
430 	release_locality(chip);
431 	return ret;
432 }
433 
434 /*
435  * st33zp24_recv received TPM response through TPM phy.
436  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
437  * @param: buf,	the buffer to store datas.
438  * @param: count, the number of bytes to send.
439  * @return: In case of success the number of bytes received.
440  *	    In other case, a < 0 value describing the issue.
441  */
442 static int st33zp24_recv(struct tpm_chip *chip, unsigned char *buf,
443 			    size_t count)
444 {
445 	int size = 0;
446 	u32 expected;
447 
448 	if (!chip)
449 		return -EBUSY;
450 
451 	if (count < TPM_HEADER_SIZE) {
452 		size = -EIO;
453 		goto out;
454 	}
455 
456 	size = recv_data(chip, buf, TPM_HEADER_SIZE);
457 	if (size < TPM_HEADER_SIZE) {
458 		dev_err(&chip->dev, "Unable to read header\n");
459 		goto out;
460 	}
461 
462 	expected = be32_to_cpu(*(__be32 *)(buf + 2));
463 	if (expected > count || expected < TPM_HEADER_SIZE) {
464 		size = -EIO;
465 		goto out;
466 	}
467 
468 	size += recv_data(chip, &buf[TPM_HEADER_SIZE],
469 			expected - TPM_HEADER_SIZE);
470 	if (size < expected) {
471 		dev_err(&chip->dev, "Unable to read remainder of result\n");
472 		size = -ETIME;
473 	}
474 
475 out:
476 	st33zp24_cancel(chip);
477 	release_locality(chip);
478 	return size;
479 }
480 
481 /*
482  * st33zp24_req_canceled
483  * @param: chip, the tpm_chip description as specified in driver/char/tpm/tpm.h.
484  * @param: status, the TPM status.
485  * @return: Does TPM ready to compute a new command ? true.
486  */
487 static bool st33zp24_req_canceled(struct tpm_chip *chip, u8 status)
488 {
489 	return (status == TPM_STS_COMMAND_READY);
490 }
491 
492 static const struct tpm_class_ops st33zp24_tpm = {
493 	.flags = TPM_OPS_AUTO_STARTUP,
494 	.send = st33zp24_send,
495 	.recv = st33zp24_recv,
496 	.cancel = st33zp24_cancel,
497 	.status = st33zp24_status,
498 	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
499 	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
500 	.req_canceled = st33zp24_req_canceled,
501 };
502 
503 /*
504  * st33zp24_probe initialize the TPM device
505  * @param: client, the i2c_client description (TPM I2C description).
506  * @param: id, the i2c_device_id struct.
507  * @return: 0 in case of success.
508  *	 -1 in other case.
509  */
510 int st33zp24_probe(void *phy_id, const struct st33zp24_phy_ops *ops,
511 		   struct device *dev, int irq, int io_lpcpd)
512 {
513 	int ret;
514 	u8 intmask = 0;
515 	struct tpm_chip *chip;
516 	struct st33zp24_dev *tpm_dev;
517 
518 	chip = tpmm_chip_alloc(dev, &st33zp24_tpm);
519 	if (IS_ERR(chip))
520 		return PTR_ERR(chip);
521 
522 	tpm_dev = devm_kzalloc(dev, sizeof(struct st33zp24_dev),
523 			       GFP_KERNEL);
524 	if (!tpm_dev)
525 		return -ENOMEM;
526 
527 	tpm_dev->phy_id = phy_id;
528 	tpm_dev->ops = ops;
529 	dev_set_drvdata(&chip->dev, tpm_dev);
530 
531 	chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
532 	chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
533 	chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
534 	chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
535 
536 	tpm_dev->locality = LOCALITY0;
537 
538 	if (irq) {
539 		/* INTERRUPT Setup */
540 		init_waitqueue_head(&tpm_dev->read_queue);
541 		tpm_dev->intrs = 0;
542 
543 		if (request_locality(chip) != LOCALITY0) {
544 			ret = -ENODEV;
545 			goto _tpm_clean_answer;
546 		}
547 
548 		clear_interruption(tpm_dev);
549 		ret = devm_request_irq(dev, irq, tpm_ioserirq_handler,
550 				IRQF_TRIGGER_HIGH, "TPM SERIRQ management",
551 				chip);
552 		if (ret < 0) {
553 			dev_err(&chip->dev, "TPM SERIRQ signals %d not available\n",
554 				irq);
555 			goto _tpm_clean_answer;
556 		}
557 
558 		intmask |= TPM_INTF_CMD_READY_INT
559 			|  TPM_INTF_STS_VALID_INT
560 			|  TPM_INTF_DATA_AVAIL_INT;
561 
562 		ret = tpm_dev->ops->send(tpm_dev->phy_id, TPM_INT_ENABLE,
563 					 &intmask, 1);
564 		if (ret < 0)
565 			goto _tpm_clean_answer;
566 
567 		intmask = TPM_GLOBAL_INT_ENABLE;
568 		ret = tpm_dev->ops->send(tpm_dev->phy_id, (TPM_INT_ENABLE + 3),
569 					 &intmask, 1);
570 		if (ret < 0)
571 			goto _tpm_clean_answer;
572 
573 		tpm_dev->irq = irq;
574 		chip->flags |= TPM_CHIP_FLAG_IRQ;
575 
576 		disable_irq_nosync(tpm_dev->irq);
577 	}
578 
579 	return tpm_chip_register(chip);
580 _tpm_clean_answer:
581 	dev_info(&chip->dev, "TPM initialization fail\n");
582 	return ret;
583 }
584 EXPORT_SYMBOL(st33zp24_probe);
585 
586 /*
587  * st33zp24_remove remove the TPM device
588  * @param: tpm_data, the tpm phy.
589  * @return: 0 in case of success.
590  */
591 int st33zp24_remove(struct tpm_chip *chip)
592 {
593 	tpm_chip_unregister(chip);
594 	return 0;
595 }
596 EXPORT_SYMBOL(st33zp24_remove);
597 
598 #ifdef CONFIG_PM_SLEEP
599 /*
600  * st33zp24_pm_suspend suspend the TPM device
601  * @param: tpm_data, the tpm phy.
602  * @param: mesg, the power management message.
603  * @return: 0 in case of success.
604  */
605 int st33zp24_pm_suspend(struct device *dev)
606 {
607 	struct tpm_chip *chip = dev_get_drvdata(dev);
608 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
609 
610 	int ret = 0;
611 
612 	if (gpio_is_valid(tpm_dev->io_lpcpd))
613 		gpio_set_value(tpm_dev->io_lpcpd, 0);
614 	else
615 		ret = tpm_pm_suspend(dev);
616 
617 	return ret;
618 } /* st33zp24_pm_suspend() */
619 EXPORT_SYMBOL(st33zp24_pm_suspend);
620 
621 /*
622  * st33zp24_pm_resume resume the TPM device
623  * @param: tpm_data, the tpm phy.
624  * @return: 0 in case of success.
625  */
626 int st33zp24_pm_resume(struct device *dev)
627 {
628 	struct tpm_chip *chip = dev_get_drvdata(dev);
629 	struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
630 	int ret = 0;
631 
632 	if (gpio_is_valid(tpm_dev->io_lpcpd)) {
633 		gpio_set_value(tpm_dev->io_lpcpd, 1);
634 		ret = wait_for_stat(chip,
635 				TPM_STS_VALID, chip->timeout_b,
636 				&tpm_dev->read_queue, false);
637 	} else {
638 		ret = tpm_pm_resume(dev);
639 		if (!ret)
640 			tpm1_do_selftest(chip);
641 	}
642 	return ret;
643 } /* st33zp24_pm_resume() */
644 EXPORT_SYMBOL(st33zp24_pm_resume);
645 #endif
646 
647 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
648 MODULE_DESCRIPTION("ST33ZP24 TPM 1.2 driver");
649 MODULE_VERSION("1.3.0");
650 MODULE_LICENSE("GPL");
651