2 * Copyright (C) 2012,2013 Infineon Technologies
5 * Peter Huewe <peter.huewe@infineon.com>
7 * Device driver for TCG/TCPA TPM (trusted platform module).
8 * Specifications at www.trustedcomputinggroup.org
10 * This device driver implements the TPM interface as defined in
11 * the TCG TPM Interface Spec version 1.2, revision 1.0 and the
12 * Infineon I2C Protocol Stack Specification v0.20.
14 * It is based on the original tpm_tis device driver from Leendert van
15 * Dorn and Kyleen Hall.
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public License as
19 * published by the Free Software Foundation, version 2 of the
24 #include <linux/i2c.h>
25 #include <linux/module.h>
26 #include <linux/wait.h>
29 /* max. buffer size supported by our TPM */
30 #define TPM_BUFSIZE 1260
32 /* max. number of iterations after I2C NAK */
35 #define SLEEP_DURATION_LOW 55
36 #define SLEEP_DURATION_HI 65
38 /* max. number of iterations after I2C NAK for 'long' commands
39 * we need this especially for sending TPM_READY, since the cleanup after the
40 * transtion to the ready state may take some time, but it is unpredictable
41 * how long it will take.
43 #define MAX_COUNT_LONG 50
45 #define SLEEP_DURATION_LONG_LOW 200
46 #define SLEEP_DURATION_LONG_HI 220
48 /* After sending TPM_READY to 'reset' the TPM we have to sleep even longer */
49 #define SLEEP_DURATION_RESET_LOW 2400
50 #define SLEEP_DURATION_RESET_HI 2600
52 /* we want to use usleep_range instead of msleep for the 5ms TPM_TIMEOUT */
53 #define TPM_TIMEOUT_US_LOW (TPM_TIMEOUT * 1000)
54 #define TPM_TIMEOUT_US_HI (TPM_TIMEOUT_US_LOW + 2000)
56 /* expected value for DIDVID register */
57 #define TPM_TIS_I2C_DID_VID_9635 0xd1150b00L
58 #define TPM_TIS_I2C_DID_VID_9645 0x001a15d1L
66 /* Structure to store I2C TPM specific stuff */
68 struct i2c_client *client;
70 u8 buf[TPM_BUFSIZE + sizeof(u8)]; /* max. buffer size + addr */
71 struct tpm_chip *chip;
72 enum i2c_chip_type chip_type;
73 unsigned int adapterlimit;
76 static struct tpm_inf_dev tpm_dev;
79 * iic_tpm_read() - read from TPM register
80 * @addr: register address to read from
81 * @buffer: provided by caller
82 * @len: number of bytes to read
84 * Read len bytes from TPM register and put them into
85 * buffer (little-endian format, i.e. first byte is put into buffer[0]).
87 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
88 * values have to be swapped.
90 * NOTE: We can't unfortunately use the combined read/write functions
91 * provided by the i2c core as the TPM currently does not support the
92 * repeated start condition and due to it's special requirements.
93 * The i2c_smbus* functions do not work for this chip.
95 * Return -EIO on error, 0 on success.
97 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
100 struct i2c_msg msg1 = {
101 .addr = tpm_dev.client->addr,
105 struct i2c_msg msg2 = {
106 .addr = tpm_dev.client->addr,
111 struct i2c_msg msgs[] = {msg1, msg2};
115 unsigned int msglen = len;
117 /* Lock the adapter for the duration of the whole sequence. */
118 if (!tpm_dev.client->adapter->algo->master_xfer)
120 i2c_lock_adapter(tpm_dev.client->adapter);
122 if (tpm_dev.chip_type == SLB9645) {
123 /* use a combined read for newer chips
124 * unfortunately the smbus functions are not suitable due to
125 * the 32 byte limit of the smbus.
126 * retries should usually not be needed, but are kept just to
127 * be on the safe side.
129 for (count = 0; count < MAX_COUNT; count++) {
130 rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2);
132 break; /* break here to skip sleep */
133 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
136 /* Expect to send one command message and one data message, but
137 * support looping over each or both if necessary.
140 /* slb9635 protocol should work in all cases */
141 for (count = 0; count < MAX_COUNT; count++) {
142 rc = __i2c_transfer(tpm_dev.client->adapter,
145 break; /* break here to skip sleep */
147 usleep_range(SLEEP_DURATION_LOW,
154 /* After the TPM has successfully received the register
155 * address it needs some time, thus we're sleeping here
156 * again, before retrieving the data
158 for (count = 0; count < MAX_COUNT; count++) {
159 if (tpm_dev.adapterlimit) {
160 msglen = min_t(unsigned int,
161 tpm_dev.adapterlimit,
165 usleep_range(SLEEP_DURATION_LOW,
167 rc = __i2c_transfer(tpm_dev.client->adapter,
170 /* Since len is unsigned, make doubly
171 * sure we do not underflow it.
180 /* If the I2C adapter rejected the request (e.g
181 * when the quirk read_max_len < len) fall back
182 * to a sane minimum value and try again.
184 if (rc == -EOPNOTSUPP)
185 tpm_dev.adapterlimit =
195 i2c_unlock_adapter(tpm_dev.client->adapter);
196 /* take care of 'guard time' */
197 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
199 /* __i2c_transfer returns the number of successfully transferred
201 * So rc should be greater than 0 here otherwise we have an error.
209 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
210 unsigned int sleep_low,
211 unsigned int sleep_hi, u8 max_count)
216 struct i2c_msg msg1 = {
217 .addr = tpm_dev.client->addr,
222 if (len > TPM_BUFSIZE)
225 if (!tpm_dev.client->adapter->algo->master_xfer)
227 i2c_lock_adapter(tpm_dev.client->adapter);
229 /* prepend the 'register address' to the buffer */
230 tpm_dev.buf[0] = addr;
231 memcpy(&(tpm_dev.buf[1]), buffer, len);
234 * NOTE: We have to use these special mechanisms here and unfortunately
235 * cannot rely on the standard behavior of i2c_transfer.
236 * Even for newer chips the smbus functions are not
237 * suitable due to the 32 byte limit of the smbus.
239 for (count = 0; count < max_count; count++) {
240 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
243 usleep_range(sleep_low, sleep_hi);
246 i2c_unlock_adapter(tpm_dev.client->adapter);
247 /* take care of 'guard time' */
248 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
250 /* __i2c_transfer returns the number of successfully transferred
252 * So rc should be greater than 0 here otherwise we have an error.
261 * iic_tpm_write() - write to TPM register
262 * @addr: register address to write to
263 * @buffer: containing data to be written
264 * @len: number of bytes to write
266 * Write len bytes from provided buffer to TPM register (little
267 * endian format, i.e. buffer[0] is written as first byte).
269 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
270 * values have to be swapped.
272 * NOTE: use this function instead of the iic_tpm_write_generic function.
274 * Return -EIO on error, 0 on success
276 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
278 return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
279 SLEEP_DURATION_HI, MAX_COUNT);
283 * This function is needed especially for the cleanup situation after
286 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
288 return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
289 SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
293 TPM_ACCESS_VALID = 0x80,
294 TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
295 TPM_ACCESS_REQUEST_PENDING = 0x04,
296 TPM_ACCESS_REQUEST_USE = 0x02,
300 TPM_STS_VALID = 0x80,
301 TPM_STS_COMMAND_READY = 0x40,
303 TPM_STS_DATA_AVAIL = 0x10,
304 TPM_STS_DATA_EXPECT = 0x08,
308 TIS_SHORT_TIMEOUT = 750, /* ms */
309 TIS_LONG_TIMEOUT = 2000, /* 2 sec */
312 #define TPM_ACCESS(l) (0x0000 | ((l) << 4))
313 #define TPM_STS(l) (0x0001 | ((l) << 4))
314 #define TPM_DATA_FIFO(l) (0x0005 | ((l) << 4))
315 #define TPM_DID_VID(l) (0x0006 | ((l) << 4))
317 static bool check_locality(struct tpm_chip *chip, int loc)
322 rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
326 if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
327 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
328 tpm_dev.locality = loc;
335 /* implementation similar to tpm_tis */
336 static void release_locality(struct tpm_chip *chip, int loc, int force)
339 if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
342 if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
343 (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
344 buf = TPM_ACCESS_ACTIVE_LOCALITY;
345 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
349 static int request_locality(struct tpm_chip *chip, int loc)
352 u8 buf = TPM_ACCESS_REQUEST_USE;
354 if (check_locality(chip, loc))
357 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
359 /* wait for burstcount */
360 stop = jiffies + chip->timeout_a;
362 if (check_locality(chip, loc))
364 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
365 } while (time_before(jiffies, stop));
370 static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
372 /* NOTE: since I2C read may fail, return 0 in this case --> time-out */
377 if (iic_tpm_read(TPM_STS(tpm_dev.locality), &buf, 1) < 0)
381 /* if locallity is set STS should not be 0xFF */
382 } while ((buf == 0xFF) && i < 10);
387 static void tpm_tis_i2c_ready(struct tpm_chip *chip)
389 /* this causes the current command to be aborted */
390 u8 buf = TPM_STS_COMMAND_READY;
391 iic_tpm_write_long(TPM_STS(tpm_dev.locality), &buf, 1);
394 static ssize_t get_burstcount(struct tpm_chip *chip)
400 /* wait for burstcount */
401 /* which timeout value, spec has 2 answers (c & d) */
402 stop = jiffies + chip->timeout_d;
404 /* Note: STS is little endian */
405 if (iic_tpm_read(TPM_STS(tpm_dev.locality)+1, buf, 3) < 0)
408 burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
413 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
414 } while (time_before(jiffies, stop));
418 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
423 /* check current status */
424 *status = tpm_tis_i2c_status(chip);
425 if ((*status != 0xFF) && (*status & mask) == mask)
428 stop = jiffies + timeout;
430 /* since we just checked the status, give the TPM some time */
431 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
432 *status = tpm_tis_i2c_status(chip);
433 if ((*status & mask) == mask)
436 } while (time_before(jiffies, stop));
441 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
448 while (size < count) {
449 burstcnt = get_burstcount(chip);
451 /* burstcnt < 0 = TPM is busy */
455 /* limit received data to max. left */
456 if (burstcnt > (count - size))
457 burstcnt = count - size;
459 rc = iic_tpm_read(TPM_DATA_FIFO(tpm_dev.locality),
460 &(buf[size]), burstcnt);
466 /* avoid endless loop in case of broken HW */
467 if (retries > MAX_COUNT_LONG)
473 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
479 if (count < TPM_HEADER_SIZE) {
484 /* read first 10 bytes, including tag, paramsize, and result */
485 size = recv_data(chip, buf, TPM_HEADER_SIZE);
486 if (size < TPM_HEADER_SIZE) {
487 dev_err(&chip->dev, "Unable to read header\n");
491 expected = be32_to_cpu(*(__be32 *)(buf + 2));
492 if (((size_t) expected > count) || (expected < TPM_HEADER_SIZE)) {
497 size += recv_data(chip, &buf[TPM_HEADER_SIZE],
498 expected - TPM_HEADER_SIZE);
499 if (size < expected) {
500 dev_err(&chip->dev, "Unable to read remainder of result\n");
505 wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
506 if (status & TPM_STS_DATA_AVAIL) { /* retry? */
507 dev_err(&chip->dev, "Error left over data\n");
513 tpm_tis_i2c_ready(chip);
514 /* The TPM needs some time to clean up here,
515 * so we sleep rather than keeping the bus busy
517 usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
518 release_locality(chip, tpm_dev.locality, 0);
522 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
530 if (len > TPM_BUFSIZE)
531 return -E2BIG; /* command is too long for our tpm, sorry */
533 if (request_locality(chip, 0) < 0)
536 status = tpm_tis_i2c_status(chip);
537 if ((status & TPM_STS_COMMAND_READY) == 0) {
538 tpm_tis_i2c_ready(chip);
540 (chip, TPM_STS_COMMAND_READY,
541 chip->timeout_b, &status) < 0) {
547 while (count < len - 1) {
548 burstcnt = get_burstcount(chip);
550 /* burstcnt < 0 = TPM is busy */
554 if (burstcnt > (len - 1 - count))
555 burstcnt = len - 1 - count;
557 rc = iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality),
558 &(buf[count]), burstcnt);
564 /* avoid endless loop in case of broken HW */
565 if (retries > MAX_COUNT_LONG) {
570 wait_for_stat(chip, TPM_STS_VALID,
571 chip->timeout_c, &status);
573 if ((status & TPM_STS_DATA_EXPECT) == 0) {
579 /* write last byte */
580 iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1);
581 wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
582 if ((status & TPM_STS_DATA_EXPECT) != 0) {
588 iic_tpm_write(TPM_STS(tpm_dev.locality), &sts, 1);
592 tpm_tis_i2c_ready(chip);
593 /* The TPM needs some time to clean up here,
594 * so we sleep rather than keeping the bus busy
596 usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
597 release_locality(chip, tpm_dev.locality, 0);
601 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
603 return (status == TPM_STS_COMMAND_READY);
606 static const struct tpm_class_ops tpm_tis_i2c = {
607 .flags = TPM_OPS_AUTO_STARTUP,
608 .status = tpm_tis_i2c_status,
609 .recv = tpm_tis_i2c_recv,
610 .send = tpm_tis_i2c_send,
611 .cancel = tpm_tis_i2c_ready,
612 .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
613 .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
614 .req_canceled = tpm_tis_i2c_req_canceled,
617 static int tpm_tis_i2c_init(struct device *dev)
621 struct tpm_chip *chip;
623 chip = tpmm_chip_alloc(dev, &tpm_tis_i2c);
625 return PTR_ERR(chip);
627 /* Default timeouts */
628 chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
629 chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
630 chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
631 chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
633 if (request_locality(chip, 0) != 0) {
634 dev_err(dev, "could not request locality\n");
639 /* read four bytes from DID_VID register */
640 if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
641 dev_err(dev, "could not read vendor id\n");
646 if (vendor == TPM_TIS_I2C_DID_VID_9645) {
647 tpm_dev.chip_type = SLB9645;
648 } else if (vendor == TPM_TIS_I2C_DID_VID_9635) {
649 tpm_dev.chip_type = SLB9635;
651 dev_err(dev, "vendor id did not match! ID was %08x\n", vendor);
656 dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
660 return tpm_chip_register(chip);
662 release_locality(chip, tpm_dev.locality, 1);
663 tpm_dev.client = NULL;
668 static const struct i2c_device_id tpm_tis_i2c_table[] = {
669 {"tpm_i2c_infineon"},
675 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
678 static const struct of_device_id tpm_tis_i2c_of_match[] = {
679 {.compatible = "infineon,tpm_i2c_infineon"},
680 {.compatible = "infineon,slb9635tt"},
681 {.compatible = "infineon,slb9645tt"},
684 MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match);
687 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
689 static int tpm_tis_i2c_probe(struct i2c_client *client,
690 const struct i2c_device_id *id)
693 struct device *dev = &(client->dev);
695 if (tpm_dev.client != NULL) {
696 dev_err(dev, "This driver only supports one client at a time\n");
697 return -EBUSY; /* We only support one client */
700 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
701 dev_err(dev, "no algorithms associated to the i2c bus\n");
705 tpm_dev.client = client;
706 rc = tpm_tis_i2c_init(&client->dev);
708 tpm_dev.client = NULL;
714 static int tpm_tis_i2c_remove(struct i2c_client *client)
716 struct tpm_chip *chip = tpm_dev.chip;
718 tpm_chip_unregister(chip);
719 release_locality(chip, tpm_dev.locality, 1);
720 tpm_dev.client = NULL;
725 static struct i2c_driver tpm_tis_i2c_driver = {
726 .id_table = tpm_tis_i2c_table,
727 .probe = tpm_tis_i2c_probe,
728 .remove = tpm_tis_i2c_remove,
730 .name = "tpm_i2c_infineon",
731 .pm = &tpm_tis_i2c_ops,
732 .of_match_table = of_match_ptr(tpm_tis_i2c_of_match),
736 module_i2c_driver(tpm_tis_i2c_driver);
737 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
738 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
739 MODULE_VERSION("2.2.0");
740 MODULE_LICENSE("GPL");