1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * STMicroelectronics TPM ST33ZP24 I2C UBOOT driver
4 *
5 * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
6 * Author(s): Christophe Ricard <christophe-h.ricard@st.com> for STMicroelectronics.
7 *
8 * Description: Device driver for ST33ZP24 I2C TPM TCG.
9 *
10 * This device driver implements the TPM interface as defined in
11 * the TCG TPM Interface Spec version 1.21, revision 1.0 and the
12 * STMicroelectronics Protocol Stack Specification version 1.2.0.
13 */
14
15 #include <common.h>
16 #include <dm.h>
17 #include <fdtdec.h>
18 #include <i2c.h>
19 #include <tpm-v1.h>
20 #include <errno.h>
21 #include <linux/types.h>
22 #include <asm/unaligned.h>
23
24 #include "tpm_tis.h"
25 #include "tpm_internal.h"
26
27 #define TPM_ACCESS 0x0
28 #define TPM_STS 0x18
29 #define TPM_DATA_FIFO 0x24
30
31 #define LOCALITY0 0
32
33 #define TPM_DUMMY_BYTE 0xAA
34 #define TPM_ST33ZP24_I2C_SLAVE_ADDR 0x13
35
36 #define TPM_WRITE_DIRECTION 0x80
37
38 /*
39 * st33zp24_i2c_write8_reg
40 * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
41 * @param: tpm_register, the tpm tis register where the data should be written
42 * @param: tpm_data, the tpm_data to write inside the tpm_register
43 * @param: tpm_size, The length of the data
44 * @return: Number of byte written successfully else an error code.
45 */
st33zp24_i2c_write8_reg(struct udevice * dev,u8 tpm_register,const u8 * tpm_data,size_t tpm_size)46 static int st33zp24_i2c_write8_reg(struct udevice *dev, u8 tpm_register,
47 const u8 *tpm_data, size_t tpm_size)
48 {
49 struct tpm_chip_priv *chip_priv = dev_get_uclass_priv(dev);
50
51 chip_priv->buf[0] = tpm_register;
52 memcpy(chip_priv->buf + 1, tpm_data, tpm_size);
53
54 return dm_i2c_write(dev, 0, chip_priv->buf, tpm_size + 1);
55 }
56
57 /*
58 * st33zp24_i2c_read8_reg
59 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
60 * @param: tpm_register, the tpm tis register where the data should be read
61 * @param: tpm_data, the TPM response
62 * @param: tpm_size, tpm TPM response size to read.
63 * @return: Number of byte read successfully else an error code.
64 */
st33zp24_i2c_read8_reg(struct udevice * dev,u8 tpm_register,u8 * tpm_data,size_t tpm_size)65 static int st33zp24_i2c_read8_reg(struct udevice *dev, u8 tpm_register,
66 u8 *tpm_data, size_t tpm_size)
67 {
68 int status;
69 u8 data;
70
71 data = TPM_DUMMY_BYTE;
72 status = st33zp24_i2c_write8_reg(dev, tpm_register, &data, 1);
73 if (status < 0)
74 return status;
75
76 return dm_i2c_read(dev, 0, tpm_data, tpm_size);
77 }
78
79 /*
80 * st33zp24_i2c_write
81 * Send byte to the TIS register according to the ST33ZP24 I2C protocol.
82 * @param: phy_id, the phy description
83 * @param: tpm_register, the tpm tis register where the data should be written
84 * @param: tpm_data, the tpm_data to write inside the tpm_register
85 * @param: tpm_size, the length of the data
86 * @return: number of byte written successfully: should be one if success.
87 */
st33zp24_i2c_write(struct udevice * dev,u8 tpm_register,const u8 * tpm_data,size_t tpm_size)88 static int st33zp24_i2c_write(struct udevice *dev, u8 tpm_register,
89 const u8 *tpm_data, size_t tpm_size)
90 {
91 return st33zp24_i2c_write8_reg(dev, tpm_register | TPM_WRITE_DIRECTION,
92 tpm_data, tpm_size);
93 }
94
95 /*
96 * st33zp24_i2c_read
97 * Recv byte from the TIS register according to the ST33ZP24 I2C protocol.
98 * @param: phy_id, the phy description
99 * @param: tpm_register, the tpm tis register where the data should be read
100 * @param: tpm_data, the TPM response
101 * @param: tpm_size, tpm TPM response size to read.
102 * @return: number of byte read successfully: should be one if success.
103 */
st33zp24_i2c_read(struct udevice * dev,u8 tpm_register,u8 * tpm_data,size_t tpm_size)104 static int st33zp24_i2c_read(struct udevice *dev, u8 tpm_register,
105 u8 *tpm_data, size_t tpm_size)
106 {
107 return st33zp24_i2c_read8_reg(dev, tpm_register, tpm_data, tpm_size);
108 }
109
110 /*
111 * st33zp24_i2c_release_locality release the active locality
112 * @param: chip, the tpm chip description.
113 */
st33zp24_i2c_release_locality(struct udevice * dev)114 static void st33zp24_i2c_release_locality(struct udevice *dev)
115 {
116 u8 data = TPM_ACCESS_ACTIVE_LOCALITY;
117
118 st33zp24_i2c_write(dev, TPM_ACCESS, &data, 1);
119 }
120
121 /*
122 * st33zp24_i2c_check_locality if the locality is active
123 * @param: chip, the tpm chip description
124 * @return: the active locality or -EACCES.
125 */
st33zp24_i2c_check_locality(struct udevice * dev)126 static int st33zp24_i2c_check_locality(struct udevice *dev)
127 {
128 struct tpm_chip *chip = dev_get_priv(dev);
129 u8 data;
130 u8 status;
131
132 status = st33zp24_i2c_read(dev, TPM_ACCESS, &data, 1);
133 if (!status && (data &
134 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
135 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
136 return chip->locality;
137
138 return -EACCES;
139 }
140
141 /*
142 * st33zp24_i2c_request_locality request the TPM locality
143 * @param: chip, the chip description
144 * @return: the active locality or negative value.
145 */
st33zp24_i2c_request_locality(struct udevice * dev)146 static int st33zp24_i2c_request_locality(struct udevice *dev)
147 {
148 struct tpm_chip *chip = dev_get_priv(dev);
149 unsigned long start, stop;
150 long ret;
151 u8 data;
152
153 if (st33zp24_i2c_check_locality(dev) == chip->locality)
154 return chip->locality;
155
156 data = TPM_ACCESS_REQUEST_USE;
157 ret = st33zp24_i2c_write(dev, TPM_ACCESS, &data, 1);
158 if (ret < 0)
159 return ret;
160
161 /* wait for locality activated */
162 start = get_timer(0);
163 stop = chip->timeout_a;
164 do {
165 if (st33zp24_i2c_check_locality(dev) >= 0)
166 return chip->locality;
167 udelay(TPM_TIMEOUT_MS * 1000);
168 } while (get_timer(start) < stop);
169
170 return -EACCES;
171 }
172
173 /*
174 * st33zp24_i2c_status return the TPM_STS register
175 * @param: chip, the tpm chip description
176 * @return: the TPM_STS register value.
177 */
st33zp24_i2c_status(struct udevice * dev)178 static u8 st33zp24_i2c_status(struct udevice *dev)
179 {
180 u8 data;
181
182 st33zp24_i2c_read(dev, TPM_STS, &data, 1);
183
184 return data;
185 }
186
187 /*
188 * st33zp24_i2c_get_burstcount return the burstcount address 0x19 0x1A
189 * @param: chip, the chip description
190 * return: the burstcount or -TPM_DRIVER_ERR in case of error.
191 */
st33zp24_i2c_get_burstcount(struct udevice * dev)192 static int st33zp24_i2c_get_burstcount(struct udevice *dev)
193 {
194 struct tpm_chip *chip = dev_get_priv(dev);
195 unsigned long start, stop;
196 int burstcnt, status;
197 u8 tpm_reg, temp;
198
199 /* wait for burstcount */
200 start = get_timer(0);
201 stop = chip->timeout_d;
202 do {
203 tpm_reg = TPM_STS + 1;
204 status = st33zp24_i2c_read(dev, tpm_reg, &temp, 1);
205 if (status < 0)
206 return -EBUSY;
207
208 tpm_reg = TPM_STS + 2;
209 burstcnt = temp;
210 status = st33zp24_i2c_read(dev, tpm_reg, &temp, 1);
211 if (status < 0)
212 return -EBUSY;
213
214 burstcnt |= temp << 8;
215 if (burstcnt)
216 return burstcnt;
217 udelay(TIS_SHORT_TIMEOUT_MS * 1000);
218 } while (get_timer(start) < stop);
219
220 return -EBUSY;
221 }
222
223 /*
224 * st33zp24_i2c_cancel, cancel the current command execution or
225 * set STS to COMMAND READY.
226 * @param: chip, tpm_chip description.
227 */
st33zp24_i2c_cancel(struct udevice * dev)228 static void st33zp24_i2c_cancel(struct udevice *dev)
229 {
230 u8 data;
231
232 data = TPM_STS_COMMAND_READY;
233 st33zp24_i2c_write(dev, TPM_STS, &data, 1);
234 }
235
236 /*
237 * st33zp24_i2c_wait_for_stat wait for a TPM_STS value
238 * @param: chip, the tpm chip description
239 * @param: mask, the value mask to wait
240 * @param: timeout, the timeout
241 * @param: status,
242 * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
243 */
st33zp24_i2c_wait_for_stat(struct udevice * dev,u8 mask,unsigned long timeout,int * status)244 static int st33zp24_i2c_wait_for_stat(struct udevice *dev, u8 mask,
245 unsigned long timeout, int *status)
246 {
247 unsigned long start, stop;
248
249 /* Check current status */
250 *status = st33zp24_i2c_status(dev);
251 if ((*status & mask) == mask)
252 return 0;
253
254 start = get_timer(0);
255 stop = timeout;
256 do {
257 udelay(TPM_TIMEOUT_MS * 1000);
258 *status = st33zp24_i2c_status(dev);
259 if ((*status & mask) == mask)
260 return 0;
261 } while (get_timer(start) < stop);
262
263 return -ETIME;
264 }
265
266 /*
267 * st33zp24_i2c_recv_data receive data
268 * @param: chip, the tpm chip description
269 * @param: buf, the buffer where the data are received
270 * @param: count, the number of data to receive
271 * @return: the number of bytes read from TPM FIFO.
272 */
st33zp24_i2c_recv_data(struct udevice * dev,u8 * buf,size_t count)273 static int st33zp24_i2c_recv_data(struct udevice *dev, u8 *buf, size_t count)
274 {
275 struct tpm_chip *chip = dev_get_priv(dev);
276 int size = 0, burstcnt, len, ret, status;
277
278 while (size < count &&
279 st33zp24_i2c_wait_for_stat(dev, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
280 chip->timeout_c, &status) == 0) {
281 burstcnt = st33zp24_i2c_get_burstcount(dev);
282 if (burstcnt < 0)
283 return burstcnt;
284 len = min_t(int, burstcnt, count - size);
285 ret = st33zp24_i2c_read(dev, TPM_DATA_FIFO, buf + size, len);
286 if (ret < 0)
287 return ret;
288
289 size += len;
290 }
291
292 return size;
293 }
294
295 /*
296 * st33zp24_i2c_recv received TPM response through TPM phy.
297 * @param: chip, tpm_chip description.
298 * @param: buf, the buffer to store data.
299 * @param: count, the number of bytes that can received (sizeof buf).
300 * @return: Returns zero in case of success else -EIO.
301 */
st33zp24_i2c_recv(struct udevice * dev,u8 * buf,size_t count)302 static int st33zp24_i2c_recv(struct udevice *dev, u8 *buf, size_t count)
303 {
304 struct tpm_chip *chip = dev_get_priv(dev);
305 int size;
306 unsigned int expected;
307
308 if (!chip)
309 return -ENODEV;
310
311 if (count < TPM_HEADER_SIZE) {
312 size = -EIO;
313 goto out;
314 }
315
316 size = st33zp24_i2c_recv_data(dev, buf, TPM_HEADER_SIZE);
317 if (size < TPM_HEADER_SIZE) {
318 debug("TPM error, unable to read header\n");
319 goto out;
320 }
321
322 expected = get_unaligned_be32(buf + 2);
323 if (expected > count || expected < TPM_HEADER_SIZE) {
324 size = -EIO;
325 goto out;
326 }
327
328 size += st33zp24_i2c_recv_data(dev, &buf[TPM_HEADER_SIZE],
329 expected - TPM_HEADER_SIZE);
330 if (size < expected) {
331 debug("TPM error, unable to read remaining bytes of result\n");
332 size = -EIO;
333 goto out;
334 }
335
336 out:
337 st33zp24_i2c_cancel(dev);
338 st33zp24_i2c_release_locality(dev);
339
340 return size;
341 }
342
343 /*
344 * st33zp24_i2c_send send TPM commands through TPM phy.
345 * @param: chip, tpm_chip description.
346 * @param: buf, the buffer to send.
347 * @param: len, the number of bytes to send.
348 * @return: Returns zero in case of success else the negative error code.
349 */
st33zp24_i2c_send(struct udevice * dev,const u8 * buf,size_t len)350 static int st33zp24_i2c_send(struct udevice *dev, const u8 *buf, size_t len)
351 {
352 struct tpm_chip *chip = dev_get_priv(dev);
353 u32 i, size;
354 int burstcnt, ret, status;
355 u8 data, tpm_stat;
356
357 if (!chip)
358 return -ENODEV;
359 if (len < TPM_HEADER_SIZE)
360 return -EIO;
361
362 ret = st33zp24_i2c_request_locality(dev);
363 if (ret < 0)
364 return ret;
365
366 tpm_stat = st33zp24_i2c_status(dev);
367 if ((tpm_stat & TPM_STS_COMMAND_READY) == 0) {
368 st33zp24_i2c_cancel(dev);
369 if (st33zp24_i2c_wait_for_stat(dev, TPM_STS_COMMAND_READY,
370 chip->timeout_b, &status) < 0) {
371 ret = -ETIME;
372 goto out_err;
373 }
374 }
375
376 for (i = 0; i < len - 1;) {
377 burstcnt = st33zp24_i2c_get_burstcount(dev);
378 if (burstcnt < 0)
379 return burstcnt;
380
381 size = min_t(int, len - i - 1, burstcnt);
382 ret = st33zp24_i2c_write(dev, TPM_DATA_FIFO, buf + i, size);
383 if (ret < 0)
384 goto out_err;
385
386 i += size;
387 }
388
389 tpm_stat = st33zp24_i2c_status(dev);
390 if ((tpm_stat & TPM_STS_DATA_EXPECT) == 0) {
391 ret = -EIO;
392 goto out_err;
393 }
394
395 ret = st33zp24_i2c_write(dev, TPM_DATA_FIFO, buf + len - 1, 1);
396 if (ret < 0)
397 goto out_err;
398
399 tpm_stat = st33zp24_i2c_status(dev);
400 if ((tpm_stat & TPM_STS_DATA_EXPECT) != 0) {
401 ret = -EIO;
402 goto out_err;
403 }
404
405 data = TPM_STS_GO;
406 ret = st33zp24_i2c_write(dev, TPM_STS, &data, 1);
407 if (ret < 0)
408 goto out_err;
409
410 return len;
411
412 out_err:
413 st33zp24_i2c_cancel(dev);
414 st33zp24_i2c_release_locality(dev);
415
416 return ret;
417 }
418
st33zp24_i2c_cleanup(struct udevice * dev)419 static int st33zp24_i2c_cleanup(struct udevice *dev)
420 {
421 st33zp24_i2c_cancel(dev);
422 /*
423 * The TPM needs some time to clean up here,
424 * so we sleep rather than keeping the bus busy
425 */
426 mdelay(2);
427 st33zp24_i2c_release_locality(dev);
428
429 return 0;
430 }
431
st33zp24_i2c_init(struct udevice * dev)432 static int st33zp24_i2c_init(struct udevice *dev)
433 {
434 struct tpm_chip *chip = dev_get_priv(dev);
435
436 chip->is_open = 1;
437
438 /* Default timeouts - these could move to the device tree */
439 chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
440 chip->timeout_b = TIS_LONG_TIMEOUT_MS;
441 chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
442 chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
443
444 chip->locality = LOCALITY0;
445
446 /*
447 * A timeout query to TPM can be placed here.
448 * Standard timeout values are used so far
449 */
450
451 return 0;
452 }
453
st33zp24_i2c_open(struct udevice * dev)454 static int st33zp24_i2c_open(struct udevice *dev)
455 {
456 struct tpm_chip *chip = dev_get_priv(dev);
457 int rc;
458
459 debug("%s: start\n", __func__);
460 if (chip->is_open)
461 return -EBUSY;
462
463 rc = st33zp24_i2c_init(dev);
464 if (rc < 0)
465 chip->is_open = 0;
466
467 return rc;
468 }
469
st33zp24_i2c_close(struct udevice * dev)470 static int st33zp24_i2c_close(struct udevice *dev)
471 {
472 struct tpm_chip *chip = dev_get_priv(dev);
473
474 if (chip->is_open) {
475 st33zp24_i2c_release_locality(dev);
476 chip->is_open = 0;
477 chip->vend_dev = 0;
478 }
479
480 return 0;
481 }
482
st33zp24_i2c_get_desc(struct udevice * dev,char * buf,int size)483 static int st33zp24_i2c_get_desc(struct udevice *dev, char *buf, int size)
484 {
485 struct tpm_chip *chip = dev_get_priv(dev);
486
487 if (size < 50)
488 return -ENOSPC;
489
490 return snprintf(buf, size, "1.2 TPM (%s, chip type %s device-id 0x%x)",
491 chip->is_open ? "open" : "closed",
492 dev->name,
493 chip->vend_dev >> 16);
494 }
495
496 static const struct tpm_ops st33zp24_i2c_tpm_ops = {
497 .open = st33zp24_i2c_open,
498 .close = st33zp24_i2c_close,
499 .recv = st33zp24_i2c_recv,
500 .send = st33zp24_i2c_send,
501 .cleanup = st33zp24_i2c_cleanup,
502 .get_desc = st33zp24_i2c_get_desc,
503 };
504
st33zp24_i2c_probe(struct udevice * dev)505 static int st33zp24_i2c_probe(struct udevice *dev)
506 {
507 struct tpm_chip *chip = dev_get_priv(dev);
508
509 /* Default timeouts */
510 chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
511 chip->timeout_b = TIS_LONG_TIMEOUT_MS;
512 chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
513 chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
514
515 chip->locality = LOCALITY0;
516
517 i2c_set_chip_offset_len(dev, 0);
518
519 debug("ST33ZP24 I2C TPM from STMicroelectronics found\n");
520
521 return 0;
522 }
523
st33zp24_i2c_remove(struct udevice * dev)524 static int st33zp24_i2c_remove(struct udevice *dev)
525 {
526 st33zp24_i2c_release_locality(dev);
527
528 return 0;
529 }
530
531 static const struct udevice_id st33zp24_i2c_ids[] = {
532 { .compatible = "st,st33zp24-i2c" },
533 { }
534 };
535
536 U_BOOT_DRIVER(st33zp24_i2c) = {
537 .name = "st33zp24-i2c",
538 .id = UCLASS_TPM,
539 .of_match = of_match_ptr(st33zp24_i2c_ids),
540 .probe = st33zp24_i2c_probe,
541 .remove = st33zp24_i2c_remove,
542 .ops = &st33zp24_i2c_tpm_ops,
543 .priv_auto_alloc_size = sizeof(struct tpm_chip),
544 };
545