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;
69 u8 buf[TPM_BUFSIZE + sizeof(u8)]; /* max. buffer size + addr */
70 struct tpm_chip *chip;
71 enum i2c_chip_type chip_type;
74 static struct tpm_inf_dev tpm_dev;
77 * iic_tpm_read() - read from TPM register
78 * @addr: register address to read from
79 * @buffer: provided by caller
80 * @len: number of bytes to read
82 * Read len bytes from TPM register and put them into
83 * buffer (little-endian format, i.e. first byte is put into buffer[0]).
85 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
86 * values have to be swapped.
88 * NOTE: We can't unfortunately use the combined read/write functions
89 * provided by the i2c core as the TPM currently does not support the
90 * repeated start condition and due to it's special requirements.
91 * The i2c_smbus* functions do not work for this chip.
93 * Return -EIO on error, 0 on success.
95 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
98 struct i2c_msg msg1 = {
99 .addr = tpm_dev.client->addr,
103 struct i2c_msg msg2 = {
104 .addr = tpm_dev.client->addr,
109 struct i2c_msg msgs[] = {msg1, msg2};
114 /* Lock the adapter for the duration of the whole sequence. */
115 if (!tpm_dev.client->adapter->algo->master_xfer)
117 i2c_lock_adapter(tpm_dev.client->adapter);
119 if (tpm_dev.chip_type == SLB9645) {
120 /* use a combined read for newer chips
121 * unfortunately the smbus functions are not suitable due to
122 * the 32 byte limit of the smbus.
123 * retries should usually not be needed, but are kept just to
124 * be on the safe side.
126 for (count = 0; count < MAX_COUNT; count++) {
127 rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2);
129 break; /* break here to skip sleep */
130 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
133 /* slb9635 protocol should work in all cases */
134 for (count = 0; count < MAX_COUNT; count++) {
135 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
137 break; /* break here to skip sleep */
139 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
145 /* After the TPM has successfully received the register address
146 * it needs some time, thus we're sleeping here again, before
147 * retrieving the data
149 for (count = 0; count < MAX_COUNT; count++) {
150 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
151 rc = __i2c_transfer(tpm_dev.client->adapter, &msg2, 1);
158 i2c_unlock_adapter(tpm_dev.client->adapter);
159 /* take care of 'guard time' */
160 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
162 /* __i2c_transfer returns the number of successfully transferred
164 * So rc should be greater than 0 here otherwise we have an error.
172 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
173 unsigned int sleep_low,
174 unsigned int sleep_hi, u8 max_count)
179 struct i2c_msg msg1 = {
180 .addr = tpm_dev.client->addr,
185 if (len > TPM_BUFSIZE)
188 if (!tpm_dev.client->adapter->algo->master_xfer)
190 i2c_lock_adapter(tpm_dev.client->adapter);
192 /* prepend the 'register address' to the buffer */
193 tpm_dev.buf[0] = addr;
194 memcpy(&(tpm_dev.buf[1]), buffer, len);
197 * NOTE: We have to use these special mechanisms here and unfortunately
198 * cannot rely on the standard behavior of i2c_transfer.
199 * Even for newer chips the smbus functions are not
200 * suitable due to the 32 byte limit of the smbus.
202 for (count = 0; count < max_count; count++) {
203 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
206 usleep_range(sleep_low, sleep_hi);
209 i2c_unlock_adapter(tpm_dev.client->adapter);
210 /* take care of 'guard time' */
211 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
213 /* __i2c_transfer returns the number of successfully transferred
215 * So rc should be greater than 0 here otherwise we have an error.
224 * iic_tpm_write() - write to TPM register
225 * @addr: register address to write to
226 * @buffer: containing data to be written
227 * @len: number of bytes to write
229 * Write len bytes from provided buffer to TPM register (little
230 * endian format, i.e. buffer[0] is written as first byte).
232 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
233 * values have to be swapped.
235 * NOTE: use this function instead of the iic_tpm_write_generic function.
237 * Return -EIO on error, 0 on success
239 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
241 return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
242 SLEEP_DURATION_HI, MAX_COUNT);
246 * This function is needed especially for the cleanup situation after
249 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
251 return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
252 SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
256 TPM_ACCESS_VALID = 0x80,
257 TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
258 TPM_ACCESS_REQUEST_PENDING = 0x04,
259 TPM_ACCESS_REQUEST_USE = 0x02,
263 TPM_STS_VALID = 0x80,
264 TPM_STS_COMMAND_READY = 0x40,
266 TPM_STS_DATA_AVAIL = 0x10,
267 TPM_STS_DATA_EXPECT = 0x08,
271 TIS_SHORT_TIMEOUT = 750, /* ms */
272 TIS_LONG_TIMEOUT = 2000, /* 2 sec */
275 #define TPM_ACCESS(l) (0x0000 | ((l) << 4))
276 #define TPM_STS(l) (0x0001 | ((l) << 4))
277 #define TPM_DATA_FIFO(l) (0x0005 | ((l) << 4))
278 #define TPM_DID_VID(l) (0x0006 | ((l) << 4))
280 static int check_locality(struct tpm_chip *chip, int loc)
285 rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
289 if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
290 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
291 chip->vendor.locality = loc;
298 /* implementation similar to tpm_tis */
299 static void release_locality(struct tpm_chip *chip, int loc, int force)
302 if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
305 if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
306 (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
307 buf = TPM_ACCESS_ACTIVE_LOCALITY;
308 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
312 static int request_locality(struct tpm_chip *chip, int loc)
315 u8 buf = TPM_ACCESS_REQUEST_USE;
317 if (check_locality(chip, loc) >= 0)
320 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
322 /* wait for burstcount */
323 stop = jiffies + chip->vendor.timeout_a;
325 if (check_locality(chip, loc) >= 0)
327 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
328 } while (time_before(jiffies, stop));
333 static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
335 /* NOTE: since I2C read may fail, return 0 in this case --> time-out */
340 if (iic_tpm_read(TPM_STS(chip->vendor.locality), &buf, 1) < 0)
344 /* if locallity is set STS should not be 0xFF */
345 } while ((buf == 0xFF) && i < 10);
350 static void tpm_tis_i2c_ready(struct tpm_chip *chip)
352 /* this causes the current command to be aborted */
353 u8 buf = TPM_STS_COMMAND_READY;
354 iic_tpm_write_long(TPM_STS(chip->vendor.locality), &buf, 1);
357 static ssize_t get_burstcount(struct tpm_chip *chip)
363 /* wait for burstcount */
364 /* which timeout value, spec has 2 answers (c & d) */
365 stop = jiffies + chip->vendor.timeout_d;
367 /* Note: STS is little endian */
368 if (iic_tpm_read(TPM_STS(chip->vendor.locality)+1, buf, 3) < 0)
371 burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
376 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
377 } while (time_before(jiffies, stop));
381 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
386 /* check current status */
387 *status = tpm_tis_i2c_status(chip);
388 if ((*status != 0xFF) && (*status & mask) == mask)
391 stop = jiffies + timeout;
393 /* since we just checked the status, give the TPM some time */
394 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
395 *status = tpm_tis_i2c_status(chip);
396 if ((*status & mask) == mask)
399 } while (time_before(jiffies, stop));
404 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
411 while (size < count) {
412 burstcnt = get_burstcount(chip);
414 /* burstcnt < 0 = TPM is busy */
418 /* limit received data to max. left */
419 if (burstcnt > (count - size))
420 burstcnt = count - size;
422 rc = iic_tpm_read(TPM_DATA_FIFO(chip->vendor.locality),
423 &(buf[size]), burstcnt);
429 /* avoid endless loop in case of broken HW */
430 if (retries > MAX_COUNT_LONG)
436 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
439 int expected, status;
441 if (count < TPM_HEADER_SIZE) {
446 /* read first 10 bytes, including tag, paramsize, and result */
447 size = recv_data(chip, buf, TPM_HEADER_SIZE);
448 if (size < TPM_HEADER_SIZE) {
449 dev_err(chip->pdev, "Unable to read header\n");
453 expected = be32_to_cpu(*(__be32 *)(buf + 2));
454 if ((size_t) expected > count) {
459 size += recv_data(chip, &buf[TPM_HEADER_SIZE],
460 expected - TPM_HEADER_SIZE);
461 if (size < expected) {
462 dev_err(chip->pdev, "Unable to read remainder of result\n");
467 wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c, &status);
468 if (status & TPM_STS_DATA_AVAIL) { /* retry? */
469 dev_err(chip->pdev, "Error left over data\n");
475 tpm_tis_i2c_ready(chip);
476 /* The TPM needs some time to clean up here,
477 * so we sleep rather than keeping the bus busy
479 usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
480 release_locality(chip, chip->vendor.locality, 0);
484 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
492 if (len > TPM_BUFSIZE)
493 return -E2BIG; /* command is too long for our tpm, sorry */
495 if (request_locality(chip, 0) < 0)
498 status = tpm_tis_i2c_status(chip);
499 if ((status & TPM_STS_COMMAND_READY) == 0) {
500 tpm_tis_i2c_ready(chip);
502 (chip, TPM_STS_COMMAND_READY,
503 chip->vendor.timeout_b, &status) < 0) {
509 while (count < len - 1) {
510 burstcnt = get_burstcount(chip);
512 /* burstcnt < 0 = TPM is busy */
516 if (burstcnt > (len - 1 - count))
517 burstcnt = len - 1 - count;
519 rc = iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality),
520 &(buf[count]), burstcnt);
526 /* avoid endless loop in case of broken HW */
527 if (retries > MAX_COUNT_LONG) {
532 wait_for_stat(chip, TPM_STS_VALID,
533 chip->vendor.timeout_c, &status);
535 if ((status & TPM_STS_DATA_EXPECT) == 0) {
541 /* write last byte */
542 iic_tpm_write(TPM_DATA_FIFO(chip->vendor.locality), &(buf[count]), 1);
543 wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c, &status);
544 if ((status & TPM_STS_DATA_EXPECT) != 0) {
550 iic_tpm_write(TPM_STS(chip->vendor.locality), &sts, 1);
554 tpm_tis_i2c_ready(chip);
555 /* The TPM needs some time to clean up here,
556 * so we sleep rather than keeping the bus busy
558 usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
559 release_locality(chip, chip->vendor.locality, 0);
563 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
565 return (status == TPM_STS_COMMAND_READY);
568 static const struct tpm_class_ops tpm_tis_i2c = {
569 .status = tpm_tis_i2c_status,
570 .recv = tpm_tis_i2c_recv,
571 .send = tpm_tis_i2c_send,
572 .cancel = tpm_tis_i2c_ready,
573 .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
574 .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
575 .req_canceled = tpm_tis_i2c_req_canceled,
578 static int tpm_tis_i2c_init(struct device *dev)
582 struct tpm_chip *chip;
584 chip = tpmm_chip_alloc(dev, &tpm_tis_i2c);
586 return PTR_ERR(chip);
588 /* Disable interrupts */
589 chip->vendor.irq = 0;
591 /* Default timeouts */
592 chip->vendor.timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
593 chip->vendor.timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
594 chip->vendor.timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
595 chip->vendor.timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
597 if (request_locality(chip, 0) != 0) {
598 dev_err(dev, "could not request locality\n");
603 /* read four bytes from DID_VID register */
604 if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
605 dev_err(dev, "could not read vendor id\n");
610 if (vendor == TPM_TIS_I2C_DID_VID_9645) {
611 tpm_dev.chip_type = SLB9645;
612 } else if (vendor == TPM_TIS_I2C_DID_VID_9635) {
613 tpm_dev.chip_type = SLB9635;
615 dev_err(dev, "vendor id did not match! ID was %08x\n", vendor);
620 dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
622 INIT_LIST_HEAD(&chip->vendor.list);
625 tpm_get_timeouts(chip);
626 tpm_do_selftest(chip);
628 return tpm_chip_register(chip);
630 release_locality(chip, chip->vendor.locality, 1);
631 tpm_dev.client = NULL;
636 static const struct i2c_device_id tpm_tis_i2c_table[] = {
637 {"tpm_i2c_infineon", 0},
643 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
646 static const struct of_device_id tpm_tis_i2c_of_match[] = {
648 .name = "tpm_i2c_infineon",
650 .compatible = "infineon,tpm_i2c_infineon",
656 .compatible = "infineon,slb9635tt",
662 .compatible = "infineon,slb9645tt",
667 MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match);
670 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
672 static int tpm_tis_i2c_probe(struct i2c_client *client,
673 const struct i2c_device_id *id)
676 struct device *dev = &(client->dev);
678 if (tpm_dev.client != NULL) {
679 dev_err(dev, "This driver only supports one client at a time\n");
680 return -EBUSY; /* We only support one client */
683 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
684 dev_err(dev, "no algorithms associated to the i2c bus\n");
688 tpm_dev.client = client;
689 rc = tpm_tis_i2c_init(&client->dev);
691 tpm_dev.client = NULL;
697 static int tpm_tis_i2c_remove(struct i2c_client *client)
699 struct tpm_chip *chip = tpm_dev.chip;
701 tpm_chip_unregister(chip);
702 release_locality(chip, chip->vendor.locality, 1);
703 tpm_dev.client = NULL;
708 static struct i2c_driver tpm_tis_i2c_driver = {
709 .id_table = tpm_tis_i2c_table,
710 .probe = tpm_tis_i2c_probe,
711 .remove = tpm_tis_i2c_remove,
713 .name = "tpm_i2c_infineon",
714 .pm = &tpm_tis_i2c_ops,
715 .of_match_table = of_match_ptr(tpm_tis_i2c_of_match),
719 module_i2c_driver(tpm_tis_i2c_driver);
720 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
721 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
722 MODULE_VERSION("2.2.0");
723 MODULE_LICENSE("GPL");