1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2011 Infineon Technologies
4 *
5 * Authors:
6 * Peter Huewe <huewe.external@infineon.com>
7 *
8 * Description:
9 * Device driver for TCG/TCPA TPM (trusted platform module).
10 * Specifications at www.trustedcomputinggroup.org
11 *
12 * This device driver implements the TPM interface as defined in
13 * the TCG TPM Interface Spec version 1.2, revision 1.0 and the
14 * Infineon I2C Protocol Stack Specification v0.20.
15 *
16 * It is based on the Linux kernel driver tpm.c from Leendert van
17 * Dorn, Dave Safford, Reiner Sailer, and Kyleen Hall.
18 *
19 * Version: 2.1.1
20 */
21
22 #include <common.h>
23 #include <dm.h>
24 #include <fdtdec.h>
25 #include <i2c.h>
26 #include <tpm-v1.h>
27 #include <linux/errno.h>
28 #include <linux/compiler.h>
29 #include <linux/types.h>
30 #include <linux/unaligned/be_byteshift.h>
31
32 #include "tpm_tis.h"
33 #include "tpm_internal.h"
34
35 enum i2c_chip_type {
36 SLB9635,
37 SLB9645,
38 UNKNOWN,
39 };
40
41 /* expected value for DIDVID register */
42 #define TPM_TIS_I2C_DID_VID_9635 0x000b15d1L
43 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L
44
45 static const char * const chip_name[] = {
46 [SLB9635] = "slb9635tt",
47 [SLB9645] = "slb9645tt",
48 [UNKNOWN] = "unknown/fallback to slb9635",
49 };
50
51 #define TPM_ACCESS(l) (0x0000 | ((l) << 4))
52 #define TPM_STS(l) (0x0001 | ((l) << 4))
53 #define TPM_DATA_FIFO(l) (0x0005 | ((l) << 4))
54 #define TPM_DID_VID(l) (0x0006 | ((l) << 4))
55
56 /*
57 * tpm_tis_i2c_read() - read from TPM register
58 * @addr: register address to read from
59 * @buffer: provided by caller
60 * @len: number of bytes to read
61 *
62 * Read len bytes from TPM register and put them into
63 * buffer (little-endian format, i.e. first byte is put into buffer[0]).
64 *
65 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
66 * values have to be swapped.
67 *
68 * Return -EIO on error, 0 on success.
69 */
tpm_tis_i2c_read(struct udevice * dev,u8 addr,u8 * buffer,size_t len)70 static int tpm_tis_i2c_read(struct udevice *dev, u8 addr, u8 *buffer,
71 size_t len)
72 {
73 struct tpm_chip *chip = dev_get_priv(dev);
74 int rc;
75 int count;
76 uint32_t addrbuf = addr;
77
78 if ((chip->chip_type == SLB9635) || (chip->chip_type == UNKNOWN)) {
79 /* slb9635 protocol should work in both cases */
80 for (count = 0; count < MAX_COUNT; count++) {
81 rc = dm_i2c_write(dev, 0, (uchar *)&addrbuf, 1);
82 if (rc == 0)
83 break; /* Success, break to skip sleep */
84 udelay(SLEEP_DURATION_US);
85 }
86 if (rc)
87 return rc;
88
89 /* After the TPM has successfully received the register address
90 * it needs some time, thus we're sleeping here again, before
91 * retrieving the data
92 */
93 for (count = 0; count < MAX_COUNT; count++) {
94 udelay(SLEEP_DURATION_US);
95 rc = dm_i2c_read(dev, 0, buffer, len);
96 if (rc == 0)
97 break; /* success, break to skip sleep */
98 }
99 } else {
100 /*
101 * Use a combined read for newer chips.
102 * Unfortunately the smbus functions are not suitable due to
103 * the 32 byte limit of the smbus.
104 * Retries should usually not be needed, but are kept just to
105 * be safe on the safe side.
106 */
107 for (count = 0; count < MAX_COUNT; count++) {
108 rc = dm_i2c_read(dev, addr, buffer, len);
109 if (rc == 0)
110 break; /* break here to skip sleep */
111 udelay(SLEEP_DURATION_US);
112 }
113 }
114
115 /* Take care of 'guard time' */
116 udelay(SLEEP_DURATION_US);
117 if (rc)
118 return rc;
119
120 return 0;
121 }
122
tpm_tis_i2c_write_generic(struct udevice * dev,u8 addr,const u8 * buffer,size_t len,unsigned int sleep_time_us,u8 max_count)123 static int tpm_tis_i2c_write_generic(struct udevice *dev, u8 addr,
124 const u8 *buffer, size_t len,
125 unsigned int sleep_time_us, u8 max_count)
126 {
127 struct tpm_chip_priv *priv = dev_get_uclass_priv(dev);
128 struct tpm_chip *chip = dev_get_priv(dev);
129 int rc = 0;
130 int count;
131
132 if (chip->chip_type == SLB9635) {
133 /* Prepare send buffer to include the address */
134 priv->buf[0] = addr;
135 memcpy(&(priv->buf[1]), buffer, len);
136 buffer = priv->buf;
137 len++;
138 addr = 0;
139 }
140
141 for (count = 0; count < max_count; count++) {
142 rc = dm_i2c_write(dev, addr, buffer, len);
143 if (rc == 0)
144 break; /* Success, break to skip sleep */
145 udelay(sleep_time_us);
146 }
147
148 /* take care of 'guard time' */
149 udelay(sleep_time_us);
150 if (rc)
151 return rc;
152
153 return 0;
154 }
155
156 /*
157 * tpm_tis_i2c_write() - write to TPM register
158 * @addr: register address to write to
159 * @buffer: containing data to be written
160 * @len: number of bytes to write
161 *
162 * Write len bytes from provided buffer to TPM register (little
163 * endian format, i.e. buffer[0] is written as first byte).
164 *
165 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
166 * values have to be swapped.
167 *
168 * NOTE: use this function instead of the tpm_tis_i2c_write_generic function.
169 *
170 * Return -EIO on error, 0 on success
171 */
tpm_tis_i2c_write(struct udevice * dev,u8 addr,const u8 * buffer,size_t len)172 static int tpm_tis_i2c_write(struct udevice *dev, u8 addr, const u8 *buffer,
173 size_t len)
174 {
175 return tpm_tis_i2c_write_generic(dev, addr, buffer, len,
176 SLEEP_DURATION_US, MAX_COUNT);
177 }
178
179 /*
180 * This function is needed especially for the cleanup situation after
181 * sending TPM_READY
182 */
tpm_tis_i2c_write_long(struct udevice * dev,u8 addr,u8 * buffer,size_t len)183 static int tpm_tis_i2c_write_long(struct udevice *dev, u8 addr, u8 *buffer,
184 size_t len)
185 {
186 return tpm_tis_i2c_write_generic(dev, addr, buffer, len,
187 SLEEP_DURATION_LONG_US,
188 MAX_COUNT_LONG);
189 }
190
tpm_tis_i2c_check_locality(struct udevice * dev,int loc)191 static int tpm_tis_i2c_check_locality(struct udevice *dev, int loc)
192 {
193 const u8 mask = TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID;
194 struct tpm_chip *chip = dev_get_priv(dev);
195 u8 buf;
196 int rc;
197
198 rc = tpm_tis_i2c_read(dev, TPM_ACCESS(loc), &buf, 1);
199 if (rc < 0)
200 return rc;
201
202 if ((buf & mask) == mask) {
203 chip->locality = loc;
204 return loc;
205 }
206
207 return -ENOENT;
208 }
209
tpm_tis_i2c_release_locality(struct udevice * dev,int loc,int force)210 static void tpm_tis_i2c_release_locality(struct udevice *dev, int loc,
211 int force)
212 {
213 const u8 mask = TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID;
214 u8 buf;
215
216 if (tpm_tis_i2c_read(dev, TPM_ACCESS(loc), &buf, 1) < 0)
217 return;
218
219 if (force || (buf & mask) == mask) {
220 buf = TPM_ACCESS_ACTIVE_LOCALITY;
221 tpm_tis_i2c_write(dev, TPM_ACCESS(loc), &buf, 1);
222 }
223 }
224
tpm_tis_i2c_request_locality(struct udevice * dev,int loc)225 static int tpm_tis_i2c_request_locality(struct udevice *dev, int loc)
226 {
227 struct tpm_chip *chip = dev_get_priv(dev);
228 unsigned long start, stop;
229 u8 buf = TPM_ACCESS_REQUEST_USE;
230 int rc;
231
232 rc = tpm_tis_i2c_check_locality(dev, loc);
233 if (rc >= 0) {
234 debug("%s: Already have locality\n", __func__);
235 return loc; /* We already have the locality */
236 } else if (rc != -ENOENT) {
237 debug("%s: Failed to get locality: %d\n", __func__, rc);
238 return rc;
239 }
240
241 rc = tpm_tis_i2c_write(dev, TPM_ACCESS(loc), &buf, 1);
242 if (rc) {
243 debug("%s: Failed to write to TPM: %d\n", __func__, rc);
244 return rc;
245 }
246
247 /* Wait for burstcount */
248 start = get_timer(0);
249 stop = chip->timeout_a;
250 do {
251 rc = tpm_tis_i2c_check_locality(dev, loc);
252 if (rc >= 0) {
253 debug("%s: Have locality\n", __func__);
254 return loc;
255 } else if (rc != -ENOENT) {
256 debug("%s: Failed to get locality: %d\n", __func__, rc);
257 return rc;
258 }
259 mdelay(TPM_TIMEOUT_MS);
260 } while (get_timer(start) < stop);
261 debug("%s: Timeout getting locality: %d\n", __func__, rc);
262
263 return rc;
264 }
265
tpm_tis_i2c_status(struct udevice * dev)266 static u8 tpm_tis_i2c_status(struct udevice *dev)
267 {
268 struct tpm_chip *chip = dev_get_priv(dev);
269 /* NOTE: Since i2c read may fail, return 0 in this case --> time-out */
270 u8 buf;
271
272 if (tpm_tis_i2c_read(dev, TPM_STS(chip->locality), &buf, 1) < 0)
273 return 0;
274 else
275 return buf;
276 }
277
tpm_tis_i2c_ready(struct udevice * dev)278 static int tpm_tis_i2c_ready(struct udevice *dev)
279 {
280 struct tpm_chip *chip = dev_get_priv(dev);
281 int rc;
282
283 /* This causes the current command to be aborted */
284 u8 buf = TPM_STS_COMMAND_READY;
285
286 debug("%s\n", __func__);
287 rc = tpm_tis_i2c_write_long(dev, TPM_STS(chip->locality), &buf, 1);
288 if (rc)
289 debug("%s: rc=%d\n", __func__, rc);
290
291 return rc;
292 }
293
tpm_tis_i2c_get_burstcount(struct udevice * dev)294 static ssize_t tpm_tis_i2c_get_burstcount(struct udevice *dev)
295 {
296 struct tpm_chip *chip = dev_get_priv(dev);
297 unsigned long start, stop;
298 ssize_t burstcnt;
299 u8 addr, buf[3];
300
301 /* Wait for burstcount */
302 /* XXX: Which timeout value? Spec has 2 answers (c & d) */
303 start = get_timer(0);
304 stop = chip->timeout_d;
305 do {
306 /* Note: STS is little endian */
307 addr = TPM_STS(chip->locality) + 1;
308 if (tpm_tis_i2c_read(dev, addr, buf, 3) < 0)
309 burstcnt = 0;
310 else
311 burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
312
313 if (burstcnt)
314 return burstcnt;
315 mdelay(TPM_TIMEOUT_MS);
316 } while (get_timer(start) < stop);
317
318 return -EBUSY;
319 }
320
tpm_tis_i2c_wait_for_stat(struct udevice * dev,u8 mask,unsigned long timeout,int * status)321 static int tpm_tis_i2c_wait_for_stat(struct udevice *dev, u8 mask,
322 unsigned long timeout, int *status)
323 {
324 unsigned long start, stop;
325
326 /* Check current status */
327 *status = tpm_tis_i2c_status(dev);
328 if ((*status & mask) == mask)
329 return 0;
330
331 start = get_timer(0);
332 stop = timeout;
333 do {
334 mdelay(TPM_TIMEOUT_MS);
335 *status = tpm_tis_i2c_status(dev);
336 if ((*status & mask) == mask)
337 return 0;
338 } while (get_timer(start) < stop);
339
340 return -ETIMEDOUT;
341 }
342
tpm_tis_i2c_recv_data(struct udevice * dev,u8 * buf,size_t count)343 static int tpm_tis_i2c_recv_data(struct udevice *dev, u8 *buf, size_t count)
344 {
345 struct tpm_chip *chip = dev_get_priv(dev);
346 size_t size = 0;
347 ssize_t burstcnt;
348 int rc;
349
350 while (size < count) {
351 burstcnt = tpm_tis_i2c_get_burstcount(dev);
352
353 /* burstcount < 0 -> tpm is busy */
354 if (burstcnt < 0)
355 return burstcnt;
356
357 /* Limit received data to max left */
358 if (burstcnt > (count - size))
359 burstcnt = count - size;
360
361 rc = tpm_tis_i2c_read(dev, TPM_DATA_FIFO(chip->locality),
362 &(buf[size]), burstcnt);
363 if (rc == 0)
364 size += burstcnt;
365 }
366
367 return size;
368 }
369
tpm_tis_i2c_recv(struct udevice * dev,u8 * buf,size_t count)370 static int tpm_tis_i2c_recv(struct udevice *dev, u8 *buf, size_t count)
371 {
372 struct tpm_chip *chip = dev_get_priv(dev);
373 int size = 0;
374 int status;
375 unsigned int expected;
376 int rc;
377
378 status = tpm_tis_i2c_status(dev);
379 if (status == TPM_STS_COMMAND_READY)
380 return -EINTR;
381 if ((status & (TPM_STS_DATA_AVAIL | TPM_STS_VALID)) !=
382 (TPM_STS_DATA_AVAIL | TPM_STS_VALID))
383 return -EAGAIN;
384
385 debug("...got it;\n");
386
387 /* Read first 10 bytes, including tag, paramsize, and result */
388 size = tpm_tis_i2c_recv_data(dev, buf, TPM_HEADER_SIZE);
389 if (size < TPM_HEADER_SIZE) {
390 debug("Unable to read header\n");
391 return size < 0 ? size : -EIO;
392 }
393
394 expected = get_unaligned_be32(buf + TPM_RSP_SIZE_BYTE);
395 if ((size_t)expected > count || (size_t)expected < TPM_HEADER_SIZE) {
396 debug("Error size=%x, expected=%x, count=%x\n", size, expected,
397 count);
398 return -ENOSPC;
399 }
400
401 size += tpm_tis_i2c_recv_data(dev, &buf[TPM_HEADER_SIZE],
402 expected - TPM_HEADER_SIZE);
403 if (size < expected) {
404 debug("Unable to read remainder of result\n");
405 return -ETIMEDOUT;
406 }
407
408 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_VALID, chip->timeout_c,
409 &status);
410 if (rc)
411 return rc;
412 if (status & TPM_STS_DATA_AVAIL) { /* Retry? */
413 debug("Error left over data\n");
414 return -EIO;
415 }
416
417 return size;
418 }
419
tpm_tis_i2c_send(struct udevice * dev,const u8 * buf,size_t len)420 static int tpm_tis_i2c_send(struct udevice *dev, const u8 *buf, size_t len)
421 {
422 struct tpm_chip *chip = dev_get_priv(dev);
423 int rc, status;
424 size_t burstcnt;
425 size_t count = 0;
426 int retry = 0;
427 u8 sts = TPM_STS_GO;
428
429 debug("%s: len=%d\n", __func__, len);
430 if (len > TPM_DEV_BUFSIZE)
431 return -E2BIG; /* Command is too long for our tpm, sorry */
432
433 if (tpm_tis_i2c_request_locality(dev, 0) < 0)
434 return -EBUSY;
435
436 status = tpm_tis_i2c_status(dev);
437 if ((status & TPM_STS_COMMAND_READY) == 0) {
438 rc = tpm_tis_i2c_ready(dev);
439 if (rc)
440 return rc;
441 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_COMMAND_READY,
442 chip->timeout_b, &status);
443 if (rc)
444 return rc;
445 }
446
447 burstcnt = tpm_tis_i2c_get_burstcount(dev);
448
449 /* burstcount < 0 -> tpm is busy */
450 if (burstcnt < 0)
451 return burstcnt;
452
453 while (count < len) {
454 udelay(300);
455 if (burstcnt > len - count)
456 burstcnt = len - count;
457
458 #ifdef CONFIG_TPM_TIS_I2C_BURST_LIMITATION
459 if (retry && burstcnt > CONFIG_TPM_TIS_I2C_BURST_LIMITATION_LEN)
460 burstcnt = CONFIG_TPM_TIS_I2C_BURST_LIMITATION_LEN;
461 #endif /* CONFIG_TPM_TIS_I2C_BURST_LIMITATION */
462
463 rc = tpm_tis_i2c_write(dev, TPM_DATA_FIFO(chip->locality),
464 &(buf[count]), burstcnt);
465 if (rc == 0)
466 count += burstcnt;
467 else {
468 debug("%s: error\n", __func__);
469 if (retry++ > 10)
470 return -EIO;
471 rc = tpm_tis_i2c_wait_for_stat(dev, TPM_STS_VALID,
472 chip->timeout_c,
473 &status);
474 if (rc)
475 return rc;
476
477 if ((status & TPM_STS_DATA_EXPECT) == 0)
478 return -EIO;
479 }
480 }
481
482 /* Go and do it */
483 rc = tpm_tis_i2c_write(dev, TPM_STS(chip->locality), &sts, 1);
484 if (rc < 0)
485 return rc;
486 debug("%s: done, rc=%d\n", __func__, rc);
487
488 return len;
489 }
490
tpm_tis_i2c_cleanup(struct udevice * dev)491 static int tpm_tis_i2c_cleanup(struct udevice *dev)
492 {
493 struct tpm_chip *chip = dev_get_priv(dev);
494
495 tpm_tis_i2c_ready(dev);
496 /*
497 * The TPM needs some time to clean up here,
498 * so we sleep rather than keeping the bus busy
499 */
500 mdelay(2);
501 tpm_tis_i2c_release_locality(dev, chip->locality, 0);
502
503 return 0;
504 }
505
tpm_tis_i2c_init(struct udevice * dev)506 static int tpm_tis_i2c_init(struct udevice *dev)
507 {
508 struct tpm_chip *chip = dev_get_priv(dev);
509 u32 vendor;
510 u32 expected_did_vid;
511 int rc;
512
513 chip->is_open = 1;
514
515 /* Default timeouts - these could move to the device tree */
516 chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
517 chip->timeout_b = TIS_LONG_TIMEOUT_MS;
518 chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
519 chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
520
521 rc = tpm_tis_i2c_request_locality(dev, 0);
522 if (rc < 0)
523 return rc;
524
525 /* Read four bytes from DID_VID register */
526 if (tpm_tis_i2c_read(dev, TPM_DID_VID(0), (uchar *)&vendor, 4) < 0) {
527 tpm_tis_i2c_release_locality(dev, 0, 1);
528 return -EIO;
529 }
530
531 if (chip->chip_type == SLB9635) {
532 vendor = be32_to_cpu(vendor);
533 expected_did_vid = TPM_TIS_I2C_DID_VID_9635;
534 } else {
535 /* device id and byte order has changed for newer i2c tpms */
536 expected_did_vid = TPM_TIS_I2C_DID_VID_9645;
537 }
538
539 if (chip->chip_type != UNKNOWN && vendor != expected_did_vid) {
540 pr_err("Vendor id did not match! ID was %08x\n", vendor);
541 return -ENODEV;
542 }
543
544 chip->vend_dev = vendor;
545 debug("1.2 TPM (chip type %s device-id 0x%X)\n",
546 chip_name[chip->chip_type], vendor >> 16);
547
548 /*
549 * A timeout query to TPM can be placed here.
550 * Standard timeout values are used so far
551 */
552
553 return 0;
554 }
555
tpm_tis_i2c_open(struct udevice * dev)556 static int tpm_tis_i2c_open(struct udevice *dev)
557 {
558 struct tpm_chip *chip = dev_get_priv(dev);
559 int rc;
560
561 debug("%s: start\n", __func__);
562 if (chip->is_open)
563 return -EBUSY;
564 rc = tpm_tis_i2c_init(dev);
565 if (rc < 0)
566 chip->is_open = 0;
567
568 return rc;
569 }
570
tpm_tis_i2c_close(struct udevice * dev)571 static int tpm_tis_i2c_close(struct udevice *dev)
572 {
573 struct tpm_chip *chip = dev_get_priv(dev);
574
575 if (chip->is_open) {
576 tpm_tis_i2c_release_locality(dev, chip->locality, 1);
577 chip->is_open = 0;
578 chip->vend_dev = 0;
579 }
580
581 return 0;
582 }
583
tpm_tis_get_desc(struct udevice * dev,char * buf,int size)584 static int tpm_tis_get_desc(struct udevice *dev, char *buf, int size)
585 {
586 struct tpm_chip *chip = dev_get_priv(dev);
587
588 if (size < 50)
589 return -ENOSPC;
590
591 return snprintf(buf, size, "1.2 TPM (%s, chip type %s device-id 0x%x)",
592 chip->is_open ? "open" : "closed",
593 chip_name[chip->chip_type],
594 chip->vend_dev >> 16);
595 }
596
tpm_tis_i2c_probe(struct udevice * dev)597 static int tpm_tis_i2c_probe(struct udevice *dev)
598 {
599 struct tpm_chip_priv *uc_priv = dev_get_uclass_priv(dev);
600 struct tpm_chip *chip = dev_get_priv(dev);
601
602 chip->chip_type = dev_get_driver_data(dev);
603
604 /* TODO: These need to be checked and tuned */
605 uc_priv->duration_ms[TPM_SHORT] = TIS_SHORT_TIMEOUT_MS;
606 uc_priv->duration_ms[TPM_MEDIUM] = TIS_LONG_TIMEOUT_MS;
607 uc_priv->duration_ms[TPM_LONG] = TIS_LONG_TIMEOUT_MS;
608 uc_priv->retry_time_ms = TPM_TIMEOUT_MS;
609
610 return 0;
611 }
612
613 static const struct tpm_ops tpm_tis_i2c_ops = {
614 .open = tpm_tis_i2c_open,
615 .close = tpm_tis_i2c_close,
616 .get_desc = tpm_tis_get_desc,
617 .send = tpm_tis_i2c_send,
618 .recv = tpm_tis_i2c_recv,
619 .cleanup = tpm_tis_i2c_cleanup,
620 };
621
622 static const struct udevice_id tpm_tis_i2c_ids[] = {
623 { .compatible = "infineon,slb9635tt", .data = SLB9635 },
624 { .compatible = "infineon,slb9645tt", .data = SLB9645 },
625 { }
626 };
627
628 U_BOOT_DRIVER(tpm_tis_i2c) = {
629 .name = "tpm_tis_infineon",
630 .id = UCLASS_TPM,
631 .of_match = tpm_tis_i2c_ids,
632 .ops = &tpm_tis_i2c_ops,
633 .probe = tpm_tis_i2c_probe,
634 .priv_auto_alloc_size = sizeof(struct tpm_chip),
635 };
636