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;
75 static struct tpm_inf_dev tpm_dev;
78 * iic_tpm_read() - read from TPM register
79 * @addr: register address to read from
80 * @buffer: provided by caller
81 * @len: number of bytes to read
83 * Read len bytes from TPM register and put them into
84 * buffer (little-endian format, i.e. first byte is put into buffer[0]).
86 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
87 * values have to be swapped.
89 * NOTE: We can't unfortunately use the combined read/write functions
90 * provided by the i2c core as the TPM currently does not support the
91 * repeated start condition and due to it's special requirements.
92 * The i2c_smbus* functions do not work for this chip.
94 * Return -EIO on error, 0 on success.
96 static int iic_tpm_read(u8 addr, u8 *buffer, size_t len)
99 struct i2c_msg msg1 = {
100 .addr = tpm_dev.client->addr,
104 struct i2c_msg msg2 = {
105 .addr = tpm_dev.client->addr,
110 struct i2c_msg msgs[] = {msg1, msg2};
115 /* Lock the adapter for the duration of the whole sequence. */
116 if (!tpm_dev.client->adapter->algo->master_xfer)
118 i2c_lock_adapter(tpm_dev.client->adapter);
120 if (tpm_dev.chip_type == SLB9645) {
121 /* use a combined read for newer chips
122 * unfortunately the smbus functions are not suitable due to
123 * the 32 byte limit of the smbus.
124 * retries should usually not be needed, but are kept just to
125 * be on the safe side.
127 for (count = 0; count < MAX_COUNT; count++) {
128 rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2);
130 break; /* break here to skip sleep */
131 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
134 /* slb9635 protocol should work in all cases */
135 for (count = 0; count < MAX_COUNT; count++) {
136 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
138 break; /* break here to skip sleep */
140 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
146 /* After the TPM has successfully received the register address
147 * it needs some time, thus we're sleeping here again, before
148 * retrieving the data
150 for (count = 0; count < MAX_COUNT; count++) {
151 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
152 rc = __i2c_transfer(tpm_dev.client->adapter, &msg2, 1);
159 i2c_unlock_adapter(tpm_dev.client->adapter);
160 /* take care of 'guard time' */
161 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
163 /* __i2c_transfer returns the number of successfully transferred
165 * So rc should be greater than 0 here otherwise we have an error.
173 static int iic_tpm_write_generic(u8 addr, u8 *buffer, size_t len,
174 unsigned int sleep_low,
175 unsigned int sleep_hi, u8 max_count)
180 struct i2c_msg msg1 = {
181 .addr = tpm_dev.client->addr,
186 if (len > TPM_BUFSIZE)
189 if (!tpm_dev.client->adapter->algo->master_xfer)
191 i2c_lock_adapter(tpm_dev.client->adapter);
193 /* prepend the 'register address' to the buffer */
194 tpm_dev.buf[0] = addr;
195 memcpy(&(tpm_dev.buf[1]), buffer, len);
198 * NOTE: We have to use these special mechanisms here and unfortunately
199 * cannot rely on the standard behavior of i2c_transfer.
200 * Even for newer chips the smbus functions are not
201 * suitable due to the 32 byte limit of the smbus.
203 for (count = 0; count < max_count; count++) {
204 rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1);
207 usleep_range(sleep_low, sleep_hi);
210 i2c_unlock_adapter(tpm_dev.client->adapter);
211 /* take care of 'guard time' */
212 usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI);
214 /* __i2c_transfer returns the number of successfully transferred
216 * So rc should be greater than 0 here otherwise we have an error.
225 * iic_tpm_write() - write to TPM register
226 * @addr: register address to write to
227 * @buffer: containing data to be written
228 * @len: number of bytes to write
230 * Write len bytes from provided buffer to TPM register (little
231 * endian format, i.e. buffer[0] is written as first byte).
233 * NOTE: TPM is big-endian for multi-byte values. Multi-byte
234 * values have to be swapped.
236 * NOTE: use this function instead of the iic_tpm_write_generic function.
238 * Return -EIO on error, 0 on success
240 static int iic_tpm_write(u8 addr, u8 *buffer, size_t len)
242 return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LOW,
243 SLEEP_DURATION_HI, MAX_COUNT);
247 * This function is needed especially for the cleanup situation after
250 static int iic_tpm_write_long(u8 addr, u8 *buffer, size_t len)
252 return iic_tpm_write_generic(addr, buffer, len, SLEEP_DURATION_LONG_LOW,
253 SLEEP_DURATION_LONG_HI, MAX_COUNT_LONG);
257 TPM_ACCESS_VALID = 0x80,
258 TPM_ACCESS_ACTIVE_LOCALITY = 0x20,
259 TPM_ACCESS_REQUEST_PENDING = 0x04,
260 TPM_ACCESS_REQUEST_USE = 0x02,
264 TPM_STS_VALID = 0x80,
265 TPM_STS_COMMAND_READY = 0x40,
267 TPM_STS_DATA_AVAIL = 0x10,
268 TPM_STS_DATA_EXPECT = 0x08,
272 TIS_SHORT_TIMEOUT = 750, /* ms */
273 TIS_LONG_TIMEOUT = 2000, /* 2 sec */
276 #define TPM_ACCESS(l) (0x0000 | ((l) << 4))
277 #define TPM_STS(l) (0x0001 | ((l) << 4))
278 #define TPM_DATA_FIFO(l) (0x0005 | ((l) << 4))
279 #define TPM_DID_VID(l) (0x0006 | ((l) << 4))
281 static int check_locality(struct tpm_chip *chip, int loc)
286 rc = iic_tpm_read(TPM_ACCESS(loc), &buf, 1);
290 if ((buf & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
291 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) {
292 tpm_dev.locality = loc;
299 /* implementation similar to tpm_tis */
300 static void release_locality(struct tpm_chip *chip, int loc, int force)
303 if (iic_tpm_read(TPM_ACCESS(loc), &buf, 1) < 0)
306 if (force || (buf & (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
307 (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) {
308 buf = TPM_ACCESS_ACTIVE_LOCALITY;
309 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
313 static int request_locality(struct tpm_chip *chip, int loc)
316 u8 buf = TPM_ACCESS_REQUEST_USE;
318 if (check_locality(chip, loc) >= 0)
321 iic_tpm_write(TPM_ACCESS(loc), &buf, 1);
323 /* wait for burstcount */
324 stop = jiffies + chip->timeout_a;
326 if (check_locality(chip, loc) >= 0)
328 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
329 } while (time_before(jiffies, stop));
334 static u8 tpm_tis_i2c_status(struct tpm_chip *chip)
336 /* NOTE: since I2C read may fail, return 0 in this case --> time-out */
341 if (iic_tpm_read(TPM_STS(tpm_dev.locality), &buf, 1) < 0)
345 /* if locallity is set STS should not be 0xFF */
346 } while ((buf == 0xFF) && i < 10);
351 static void tpm_tis_i2c_ready(struct tpm_chip *chip)
353 /* this causes the current command to be aborted */
354 u8 buf = TPM_STS_COMMAND_READY;
355 iic_tpm_write_long(TPM_STS(tpm_dev.locality), &buf, 1);
358 static ssize_t get_burstcount(struct tpm_chip *chip)
364 /* wait for burstcount */
365 /* which timeout value, spec has 2 answers (c & d) */
366 stop = jiffies + chip->timeout_d;
368 /* Note: STS is little endian */
369 if (iic_tpm_read(TPM_STS(tpm_dev.locality)+1, buf, 3) < 0)
372 burstcnt = (buf[2] << 16) + (buf[1] << 8) + buf[0];
377 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
378 } while (time_before(jiffies, stop));
382 static int wait_for_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
387 /* check current status */
388 *status = tpm_tis_i2c_status(chip);
389 if ((*status != 0xFF) && (*status & mask) == mask)
392 stop = jiffies + timeout;
394 /* since we just checked the status, give the TPM some time */
395 usleep_range(TPM_TIMEOUT_US_LOW, TPM_TIMEOUT_US_HI);
396 *status = tpm_tis_i2c_status(chip);
397 if ((*status & mask) == mask)
400 } while (time_before(jiffies, stop));
405 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
412 while (size < count) {
413 burstcnt = get_burstcount(chip);
415 /* burstcnt < 0 = TPM is busy */
419 /* limit received data to max. left */
420 if (burstcnt > (count - size))
421 burstcnt = count - size;
423 rc = iic_tpm_read(TPM_DATA_FIFO(tpm_dev.locality),
424 &(buf[size]), burstcnt);
430 /* avoid endless loop in case of broken HW */
431 if (retries > MAX_COUNT_LONG)
437 static int tpm_tis_i2c_recv(struct tpm_chip *chip, u8 *buf, size_t count)
440 int expected, status;
442 if (count < TPM_HEADER_SIZE) {
447 /* read first 10 bytes, including tag, paramsize, and result */
448 size = recv_data(chip, buf, TPM_HEADER_SIZE);
449 if (size < TPM_HEADER_SIZE) {
450 dev_err(&chip->dev, "Unable to read header\n");
454 expected = be32_to_cpu(*(__be32 *)(buf + 2));
455 if ((size_t) expected > count) {
460 size += recv_data(chip, &buf[TPM_HEADER_SIZE],
461 expected - TPM_HEADER_SIZE);
462 if (size < expected) {
463 dev_err(&chip->dev, "Unable to read remainder of result\n");
468 wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
469 if (status & TPM_STS_DATA_AVAIL) { /* retry? */
470 dev_err(&chip->dev, "Error left over data\n");
476 tpm_tis_i2c_ready(chip);
477 /* The TPM needs some time to clean up here,
478 * so we sleep rather than keeping the bus busy
480 usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
481 release_locality(chip, tpm_dev.locality, 0);
485 static int tpm_tis_i2c_send(struct tpm_chip *chip, u8 *buf, size_t len)
493 if (len > TPM_BUFSIZE)
494 return -E2BIG; /* command is too long for our tpm, sorry */
496 if (request_locality(chip, 0) < 0)
499 status = tpm_tis_i2c_status(chip);
500 if ((status & TPM_STS_COMMAND_READY) == 0) {
501 tpm_tis_i2c_ready(chip);
503 (chip, TPM_STS_COMMAND_READY,
504 chip->timeout_b, &status) < 0) {
510 while (count < len - 1) {
511 burstcnt = get_burstcount(chip);
513 /* burstcnt < 0 = TPM is busy */
517 if (burstcnt > (len - 1 - count))
518 burstcnt = len - 1 - count;
520 rc = iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality),
521 &(buf[count]), burstcnt);
527 /* avoid endless loop in case of broken HW */
528 if (retries > MAX_COUNT_LONG) {
533 wait_for_stat(chip, TPM_STS_VALID,
534 chip->timeout_c, &status);
536 if ((status & TPM_STS_DATA_EXPECT) == 0) {
542 /* write last byte */
543 iic_tpm_write(TPM_DATA_FIFO(tpm_dev.locality), &(buf[count]), 1);
544 wait_for_stat(chip, TPM_STS_VALID, chip->timeout_c, &status);
545 if ((status & TPM_STS_DATA_EXPECT) != 0) {
551 iic_tpm_write(TPM_STS(tpm_dev.locality), &sts, 1);
555 tpm_tis_i2c_ready(chip);
556 /* The TPM needs some time to clean up here,
557 * so we sleep rather than keeping the bus busy
559 usleep_range(SLEEP_DURATION_RESET_LOW, SLEEP_DURATION_RESET_HI);
560 release_locality(chip, tpm_dev.locality, 0);
564 static bool tpm_tis_i2c_req_canceled(struct tpm_chip *chip, u8 status)
566 return (status == TPM_STS_COMMAND_READY);
569 static const struct tpm_class_ops tpm_tis_i2c = {
570 .flags = TPM_OPS_AUTO_STARTUP,
571 .status = tpm_tis_i2c_status,
572 .recv = tpm_tis_i2c_recv,
573 .send = tpm_tis_i2c_send,
574 .cancel = tpm_tis_i2c_ready,
575 .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
576 .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
577 .req_canceled = tpm_tis_i2c_req_canceled,
580 static int tpm_tis_i2c_init(struct device *dev)
584 struct tpm_chip *chip;
586 chip = tpmm_chip_alloc(dev, &tpm_tis_i2c);
588 return PTR_ERR(chip);
590 /* Default timeouts */
591 chip->timeout_a = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
592 chip->timeout_b = msecs_to_jiffies(TIS_LONG_TIMEOUT);
593 chip->timeout_c = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
594 chip->timeout_d = msecs_to_jiffies(TIS_SHORT_TIMEOUT);
596 if (request_locality(chip, 0) != 0) {
597 dev_err(dev, "could not request locality\n");
602 /* read four bytes from DID_VID register */
603 if (iic_tpm_read(TPM_DID_VID(0), (u8 *)&vendor, 4) < 0) {
604 dev_err(dev, "could not read vendor id\n");
609 if (vendor == TPM_TIS_I2C_DID_VID_9645) {
610 tpm_dev.chip_type = SLB9645;
611 } else if (vendor == TPM_TIS_I2C_DID_VID_9635) {
612 tpm_dev.chip_type = SLB9635;
614 dev_err(dev, "vendor id did not match! ID was %08x\n", vendor);
619 dev_info(dev, "1.2 TPM (device-id 0x%X)\n", vendor >> 16);
623 return tpm_chip_register(chip);
625 release_locality(chip, tpm_dev.locality, 1);
626 tpm_dev.client = NULL;
631 static const struct i2c_device_id tpm_tis_i2c_table[] = {
632 {"tpm_i2c_infineon", 0},
638 MODULE_DEVICE_TABLE(i2c, tpm_tis_i2c_table);
641 static const struct of_device_id tpm_tis_i2c_of_match[] = {
643 .name = "tpm_i2c_infineon",
645 .compatible = "infineon,tpm_i2c_infineon",
651 .compatible = "infineon,slb9635tt",
657 .compatible = "infineon,slb9645tt",
662 MODULE_DEVICE_TABLE(of, tpm_tis_i2c_of_match);
665 static SIMPLE_DEV_PM_OPS(tpm_tis_i2c_ops, tpm_pm_suspend, tpm_pm_resume);
667 static int tpm_tis_i2c_probe(struct i2c_client *client,
668 const struct i2c_device_id *id)
671 struct device *dev = &(client->dev);
673 if (tpm_dev.client != NULL) {
674 dev_err(dev, "This driver only supports one client at a time\n");
675 return -EBUSY; /* We only support one client */
678 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
679 dev_err(dev, "no algorithms associated to the i2c bus\n");
683 tpm_dev.client = client;
684 rc = tpm_tis_i2c_init(&client->dev);
686 tpm_dev.client = NULL;
692 static int tpm_tis_i2c_remove(struct i2c_client *client)
694 struct tpm_chip *chip = tpm_dev.chip;
696 tpm_chip_unregister(chip);
697 release_locality(chip, tpm_dev.locality, 1);
698 tpm_dev.client = NULL;
703 static struct i2c_driver tpm_tis_i2c_driver = {
704 .id_table = tpm_tis_i2c_table,
705 .probe = tpm_tis_i2c_probe,
706 .remove = tpm_tis_i2c_remove,
708 .name = "tpm_i2c_infineon",
709 .pm = &tpm_tis_i2c_ops,
710 .of_match_table = of_match_ptr(tpm_tis_i2c_of_match),
714 module_i2c_driver(tpm_tis_i2c_driver);
715 MODULE_AUTHOR("Peter Huewe <peter.huewe@infineon.com>");
716 MODULE_DESCRIPTION("TPM TIS I2C Infineon Driver");
717 MODULE_VERSION("2.2.0");
718 MODULE_LICENSE("GPL");