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[u-boot] / drivers / tpm / tpm_tis_st33zp24_spi.c
1 /*
2  * STMicroelectronics TPM ST33ZP24 SPI UBOOT driver
3  *
4  * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
5  * Author(s): Christophe Ricard <christophe-h.ricard@st.com> for STMicroelectronics.
6  *
7  * Description: Device driver for ST33ZP24 SPI TPM TCG.
8  *
9  * This device driver implements the TPM interface as defined in
10  * the TCG TPM Interface Spec version 1.21, revision 1.0 and the
11  * STMicroelectronics Protocol Stack Specification version 1.2.0.
12  *
13  * SPDX-License-Identifier:     GPL-2.0+
14  */
15
16 #include <common.h>
17 #include <dm.h>
18 #include <fdtdec.h>
19 #include <spi.h>
20 #include <tpm.h>
21 #include <errno.h>
22 #include <linux/types.h>
23 #include <asm/unaligned.h>
24 #include <linux/compat.h>
25
26 #include "tpm_tis.h"
27 #include "tpm_internal.h"
28
29 #define TPM_ACCESS                      0x0
30 #define TPM_STS                         0x18
31 #define TPM_DATA_FIFO                   0x24
32
33 #define LOCALITY0                       0
34
35 #define TPM_DATA_FIFO                           0x24
36 #define TPM_INTF_CAPABILITY                     0x14
37
38 #define TPM_DUMMY_BYTE                          0x00
39 #define TPM_WRITE_DIRECTION                     0x80
40
41 #define MAX_SPI_LATENCY                         15
42 #define LOCALITY0                               0
43
44 #define ST33ZP24_OK                                     0x5A
45 #define ST33ZP24_UNDEFINED_ERR                          0x80
46 #define ST33ZP24_BADLOCALITY                            0x81
47 #define ST33ZP24_TISREGISTER_UKNOWN                     0x82
48 #define ST33ZP24_LOCALITY_NOT_ACTIVATED                 0x83
49 #define ST33ZP24_HASH_END_BEFORE_HASH_START             0x84
50 #define ST33ZP24_BAD_COMMAND_ORDER                      0x85
51 #define ST33ZP24_INCORECT_RECEIVED_LENGTH               0x86
52 #define ST33ZP24_TPM_FIFO_OVERFLOW                      0x89
53 #define ST33ZP24_UNEXPECTED_READ_FIFO                   0x8A
54 #define ST33ZP24_UNEXPECTED_WRITE_FIFO                  0x8B
55 #define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END    0x90
56 #define ST33ZP24_DUMMY_BYTES                            0x00
57
58 /*
59  * TPM command can be up to 2048 byte, A TPM response can be up to
60  * 1024 byte.
61  * Between command and response, there are latency byte (up to 15
62  * usually on st33zp24 2 are enough).
63  *
64  * Overall when sending a command and expecting an answer we need if
65  * worst case:
66  * 2048 (for the TPM command) + 1024 (for the TPM answer).  We need
67  * some latency byte before the answer is available (max 15).
68  * We have 2048 + 1024 + 15.
69  */
70 #define ST33ZP24_SPI_BUFFER_SIZE (TPM_BUFSIZE + (TPM_BUFSIZE / 2) +\
71                                   MAX_SPI_LATENCY)
72
73 struct st33zp24_spi_phy {
74         int latency;
75
76         u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
77         u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];
78 };
79
80 static int st33zp24_spi_status_to_errno(u8 code)
81 {
82         switch (code) {
83         case ST33ZP24_OK:
84                 return 0;
85         case ST33ZP24_UNDEFINED_ERR:
86         case ST33ZP24_BADLOCALITY:
87         case ST33ZP24_TISREGISTER_UKNOWN:
88         case ST33ZP24_LOCALITY_NOT_ACTIVATED:
89         case ST33ZP24_HASH_END_BEFORE_HASH_START:
90         case ST33ZP24_BAD_COMMAND_ORDER:
91         case ST33ZP24_UNEXPECTED_READ_FIFO:
92         case ST33ZP24_UNEXPECTED_WRITE_FIFO:
93         case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END:
94                 return -EPROTO;
95         case ST33ZP24_INCORECT_RECEIVED_LENGTH:
96         case ST33ZP24_TPM_FIFO_OVERFLOW:
97                 return -EMSGSIZE;
98         case ST33ZP24_DUMMY_BYTES:
99                 return -ENOSYS;
100         }
101         return code;
102 }
103
104 /*
105  * st33zp24_spi_send
106  * Send byte to TPM register according to the ST33ZP24 SPI protocol.
107  * @param: tpm, the chip description
108  * @param: tpm_register, the tpm tis register where the data should be written
109  * @param: tpm_data, the tpm_data to write inside the tpm_register
110  * @param: tpm_size, The length of the data
111  * @return: should be zero if success else a negative error code.
112  */
113 static int st33zp24_spi_write(struct udevice *dev, u8 tpm_register,
114                               const u8 *tpm_data, size_t tpm_size)
115 {
116         int total_length = 0, ret;
117         struct spi_slave *slave = dev_get_parent_priv(dev);
118         struct st33zp24_spi_phy *phy = dev_get_platdata(dev);
119
120         u8 *tx_buf = (u8 *)phy->tx_buf;
121         u8 *rx_buf = phy->rx_buf;
122
123         tx_buf[total_length++] = TPM_WRITE_DIRECTION | LOCALITY0;
124         tx_buf[total_length++] = tpm_register;
125
126         if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
127                 tx_buf[total_length++] = tpm_size >> 8;
128                 tx_buf[total_length++] = tpm_size;
129         }
130         memcpy(tx_buf + total_length, tpm_data, tpm_size);
131         total_length += tpm_size;
132
133         memset(tx_buf + total_length, TPM_DUMMY_BYTE, phy->latency);
134
135         total_length += phy->latency;
136
137         ret = spi_claim_bus(slave);
138         if (ret < 0)
139                 return ret;
140
141         ret = spi_xfer(slave, total_length * 8, tx_buf, rx_buf,
142                        SPI_XFER_BEGIN | SPI_XFER_END);
143         if (ret < 0)
144                 return ret;
145
146         spi_release_bus(slave);
147
148         if (ret == 0)
149                 ret = rx_buf[total_length - 1];
150
151         return st33zp24_spi_status_to_errno(ret);
152 }
153
154 /*
155  * spi_st33zp24_spi_read8_reg
156  * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
157  * @param: tpm, the chip description
158  * @param: tpm_loc, the locality to read register from
159  * @param: tpm_register, the tpm tis register where the data should be read
160  * @param: tpm_data, the TPM response
161  * @param: tpm_size, tpm TPM response size to read.
162  * @return: should be zero if success else a negative error code.
163  */
164 static u8 st33zp24_spi_read8_reg(struct udevice *dev, u8 tpm_register,
165                                  u8 *tpm_data, size_t tpm_size)
166 {
167         int total_length = 0, ret;
168         struct spi_slave *slave = dev_get_parent_priv(dev);
169         struct st33zp24_spi_phy *phy = dev_get_platdata(dev);
170
171         u8 *tx_buf = (u8 *)phy->tx_buf;
172         u8 *rx_buf = phy->rx_buf;
173
174         /* Pre-Header */
175         tx_buf[total_length++] = LOCALITY0;
176         tx_buf[total_length++] = tpm_register;
177
178         memset(&tx_buf[total_length], TPM_DUMMY_BYTE,
179                phy->latency + tpm_size);
180         total_length += phy->latency + tpm_size;
181
182         ret = spi_claim_bus(slave);
183         if (ret < 0)
184                 return 0;
185
186         ret = spi_xfer(slave, total_length * 8, tx_buf, rx_buf,
187                        SPI_XFER_BEGIN | SPI_XFER_END);
188         if (ret < 0)
189                 return 0;
190
191         spi_release_bus(slave);
192
193         if (tpm_size > 0 && ret == 0) {
194                 ret = rx_buf[total_length - tpm_size - 1];
195                 memcpy(tpm_data, rx_buf + total_length - tpm_size, tpm_size);
196         }
197         return ret;
198 }
199
200 /*
201  * st33zp24_spi_recv
202  * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
203  * @param: phy_id, the phy description
204  * @param: tpm_register, the tpm tis register where the data should be read
205  * @param: tpm_data, the TPM response
206  * @param: tpm_size, tpm TPM response size to read.
207  * @return: number of byte read successfully: should be one if success.
208  */
209 static int st33zp24_spi_read(struct udevice *dev, u8 tpm_register,
210                              u8 *tpm_data, size_t tpm_size)
211 {
212         int ret;
213
214         ret = st33zp24_spi_read8_reg(dev, tpm_register, tpm_data, tpm_size);
215         if (!st33zp24_spi_status_to_errno(ret))
216                 return tpm_size;
217
218         return ret;
219 }
220
221 static int st33zp24_spi_evaluate_latency(struct udevice *dev)
222 {
223         int latency = 1, status = 0;
224         u8 data = 0;
225         struct st33zp24_spi_phy *phy = dev_get_platdata(dev);
226
227         while (!status && latency < MAX_SPI_LATENCY) {
228                 phy->latency = latency;
229                 status = st33zp24_spi_read8_reg(dev, TPM_INTF_CAPABILITY,
230                                                 &data, 1);
231                 latency++;
232         }
233         if (status < 0)
234                 return status;
235         if (latency == MAX_SPI_LATENCY)
236                 return -ENODEV;
237
238         return latency - 1;
239 }
240
241 /*
242  * st33zp24_spi_release_locality release the active locality
243  * @param: chip, the tpm chip description.
244  */
245 static void st33zp24_spi_release_locality(struct udevice *dev)
246 {
247         u8 data = TPM_ACCESS_ACTIVE_LOCALITY;
248
249         st33zp24_spi_write(dev, TPM_ACCESS, &data, 1);
250 }
251
252 /*
253  * st33zp24_spi_check_locality if the locality is active
254  * @param: chip, the tpm chip description
255  * @return: the active locality or -EACCES.
256  */
257 static int st33zp24_spi_check_locality(struct udevice *dev)
258 {
259         u8 data;
260         u8 status;
261         struct tpm_chip *chip = dev_get_priv(dev);
262
263         status = st33zp24_spi_read(dev, TPM_ACCESS, &data, 1);
264         if (status && (data &
265                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
266                 (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
267                 return chip->locality;
268
269         return -EACCES;
270 }
271
272 /*
273  * st33zp24_spi_request_locality request the TPM locality
274  * @param: chip, the chip description
275  * @return: the active locality or negative value.
276  */
277 static int st33zp24_spi_request_locality(struct udevice *dev)
278 {
279         unsigned long start, stop;
280         long ret;
281         u8 data;
282         struct tpm_chip *chip = dev_get_priv(dev);
283
284         if (st33zp24_spi_check_locality(dev) == chip->locality)
285                 return chip->locality;
286
287         data = TPM_ACCESS_REQUEST_USE;
288         ret = st33zp24_spi_write(dev, TPM_ACCESS, &data, 1);
289         if (ret < 0)
290                 return ret;
291
292         /* wait for locality activated */
293         start = get_timer(0);
294         stop = chip->timeout_a;
295         do {
296                 if (st33zp24_spi_check_locality(dev) >= 0)
297                         return chip->locality;
298                 udelay(TPM_TIMEOUT_MS * 1000);
299         } while  (get_timer(start) < stop);
300
301         return -EACCES;
302 }
303
304 /*
305  * st33zp24_spi_status return the TPM_STS register
306  * @param: chip, the tpm chip description
307  * @return: the TPM_STS register value.
308  */
309 static u8 st33zp24_spi_status(struct udevice *dev)
310 {
311         u8 data;
312
313         st33zp24_spi_read(dev, TPM_STS, &data, 1);
314         return data;
315 }
316
317 /*
318  * st33zp24_spi_get_burstcount return the burstcount address 0x19 0x1A
319  * @param: chip, the chip description
320  * return: the burstcount or -TPM_DRIVER_ERR in case of error.
321  */
322 static int st33zp24_spi_get_burstcount(struct udevice *dev)
323 {
324         struct tpm_chip *chip = dev_get_priv(dev);
325         unsigned long start, stop;
326         int burstcnt, status;
327         u8 tpm_reg, temp;
328
329         /* wait for burstcount */
330         start = get_timer(0);
331         stop = chip->timeout_d;
332         do {
333                 tpm_reg = TPM_STS + 1;
334                 status = st33zp24_spi_read(dev, tpm_reg, &temp, 1);
335                 if (status < 0)
336                         return -EBUSY;
337
338                 tpm_reg = TPM_STS + 2;
339                 burstcnt = temp;
340                 status = st33zp24_spi_read(dev, tpm_reg, &temp, 1);
341                 if (status < 0)
342                         return -EBUSY;
343
344                 burstcnt |= temp << 8;
345                 if (burstcnt)
346                         return burstcnt;
347                 udelay(TIS_SHORT_TIMEOUT_MS * 1000);
348         } while (get_timer(start) < stop);
349
350         return -EBUSY;
351 }
352
353 /*
354  * st33zp24_spi_cancel, cancel the current command execution or
355  * set STS to COMMAND READY.
356  * @param: chip, tpm_chip description.
357  */
358 static void st33zp24_spi_cancel(struct udevice *dev)
359 {
360         u8 data;
361
362         data = TPM_STS_COMMAND_READY;
363         st33zp24_spi_write(dev, TPM_STS, &data, 1);
364 }
365
366 /*
367  * st33zp24_spi_wait_for_stat wait for a TPM_STS value
368  * @param: chip, the tpm chip description
369  * @param: mask, the value mask to wait
370  * @param: timeout, the timeout
371  * @param: status,
372  * @return: the tpm status, 0 if success, -ETIME if timeout is reached.
373  */
374 static int st33zp24_spi_wait_for_stat(struct udevice *dev, u8 mask,
375                                   unsigned long timeout, int *status)
376 {
377         unsigned long start, stop;
378
379         /* Check current status */
380         *status = st33zp24_spi_status(dev);
381         if ((*status & mask) == mask)
382                 return 0;
383
384         start = get_timer(0);
385         stop = timeout;
386         do {
387                 udelay(TPM_TIMEOUT_MS * 1000);
388                 *status = st33zp24_spi_status(dev);
389                 if ((*status & mask) == mask)
390                         return 0;
391         } while (get_timer(start) < stop);
392
393         return -ETIME;
394 }
395
396 /*
397  * st33zp24_spi_recv_data receive data
398  * @param: chip, the tpm chip description
399  * @param: buf, the buffer where the data are received
400  * @param: count, the number of data to receive
401  * @return: the number of bytes read from TPM FIFO.
402  */
403 static int st33zp24_spi_recv_data(struct udevice *dev, u8 *buf, size_t count)
404 {
405         struct tpm_chip *chip = dev_get_priv(dev);
406         int size = 0, burstcnt, len, ret, status;
407
408         while (size < count &&
409                st33zp24_spi_wait_for_stat(dev, TPM_STS_DATA_AVAIL | TPM_STS_VALID,
410                                 chip->timeout_c, &status) == 0) {
411                 burstcnt = st33zp24_spi_get_burstcount(dev);
412                 if (burstcnt < 0)
413                         return burstcnt;
414                 len = min_t(int, burstcnt, count - size);
415                 ret = st33zp24_spi_read(dev, TPM_DATA_FIFO, buf + size, len);
416                 if (ret < 0)
417                         return ret;
418
419                 size += len;
420         }
421         return size;
422 }
423
424 /*
425  * st33zp24_spi_recv received TPM response through TPM phy.
426  * @param: chip, tpm_chip description.
427  * @param: buf, the buffer to store data.
428  * @param: count, the number of bytes that can received (sizeof buf).
429  * @return: Returns zero in case of success else -EIO.
430  */
431 static int st33zp24_spi_recv(struct udevice *dev, u8 *buf, size_t count)
432 {
433         struct tpm_chip *chip = dev_get_priv(dev);
434         int size, expected;
435
436         if (!chip)
437                 return -ENODEV;
438
439         if (count < TPM_HEADER_SIZE) {
440                 size = -EIO;
441                 goto out;
442         }
443
444         size = st33zp24_spi_recv_data(dev, buf, TPM_HEADER_SIZE);
445         if (size < TPM_HEADER_SIZE) {
446                 debug("TPM error, unable to read header\n");
447                 goto out;
448         }
449
450         expected = get_unaligned_be32(buf + 2);
451         if (expected > count) {
452                 size = -EIO;
453                 goto out;
454         }
455
456         size += st33zp24_spi_recv_data(dev, &buf[TPM_HEADER_SIZE],
457                                    expected - TPM_HEADER_SIZE);
458         if (size < expected) {
459                 debug("TPM error, unable to read remaining bytes of result\n");
460                 size = -EIO;
461                 goto out;
462         }
463
464 out:
465         st33zp24_spi_cancel(dev);
466         st33zp24_spi_release_locality(dev);
467
468         return size;
469 }
470
471 /*
472  * st33zp24_spi_send send TPM commands through TPM phy.
473  * @param: chip, tpm_chip description.
474  * @param: buf, the buffer to send.
475  * @param: len, the number of bytes to send.
476  * @return: Returns zero in case of success else the negative error code.
477  */
478 static int st33zp24_spi_send(struct udevice *dev, const u8 *buf, size_t len)
479 {
480         struct tpm_chip *chip = dev_get_priv(dev);
481         u32 i, size;
482         int burstcnt, ret, status;
483         u8 data, tpm_stat;
484
485         if (!chip)
486                 return -ENODEV;
487         if (len < TPM_HEADER_SIZE)
488                 return -EIO;
489
490         ret = st33zp24_spi_request_locality(dev);
491         if (ret < 0)
492                 return ret;
493
494         tpm_stat = st33zp24_spi_status(dev);
495         if ((tpm_stat & TPM_STS_COMMAND_READY) == 0) {
496                 st33zp24_spi_cancel(dev);
497                 if (st33zp24_spi_wait_for_stat(dev, TPM_STS_COMMAND_READY,
498                                                chip->timeout_b, &status) < 0) {
499                         ret = -ETIME;
500                         goto out_err;
501                 }
502         }
503
504         for (i = 0; i < len - 1;) {
505                 burstcnt = st33zp24_spi_get_burstcount(dev);
506                 if (burstcnt < 0)
507                         return burstcnt;
508
509                 size = min_t(int, len - i - 1, burstcnt);
510                 ret = st33zp24_spi_write(dev, TPM_DATA_FIFO, buf + i, size);
511                 if (ret < 0)
512                         goto out_err;
513
514                 i += size;
515         }
516
517         tpm_stat = st33zp24_spi_status(dev);
518         if ((tpm_stat & TPM_STS_DATA_EXPECT) == 0) {
519                 ret = -EIO;
520                 goto out_err;
521         }
522
523         ret = st33zp24_spi_write(dev, TPM_DATA_FIFO, buf + len - 1, 1);
524         if (ret < 0)
525                 goto out_err;
526
527         tpm_stat = st33zp24_spi_status(dev);
528         if ((tpm_stat & TPM_STS_DATA_EXPECT) != 0) {
529                 ret = -EIO;
530                 goto out_err;
531         }
532
533         data = TPM_STS_GO;
534         ret = st33zp24_spi_write(dev, TPM_STS, &data, 1);
535         if (ret < 0)
536                 goto out_err;
537
538         return len;
539
540 out_err:
541         st33zp24_spi_cancel(dev);
542         st33zp24_spi_release_locality(dev);
543
544         return ret;
545 }
546
547 static int st33zp24_spi_cleanup(struct udevice *dev)
548 {
549         st33zp24_spi_cancel(dev);
550         /*
551          * The TPM needs some time to clean up here,
552          * so we sleep rather than keeping the bus busy
553          */
554         mdelay(2);
555         st33zp24_spi_release_locality(dev);
556
557         return 0;
558 }
559
560 static int st33zp24_spi_init(struct udevice *dev)
561 {
562         struct tpm_chip *chip = dev_get_priv(dev);
563         struct st33zp24_spi_phy *phy = dev_get_platdata(dev);
564
565         chip->is_open = 1;
566
567         /* Default timeouts - these could move to the device tree */
568         chip->timeout_a = TIS_SHORT_TIMEOUT_MS;
569         chip->timeout_b = TIS_LONG_TIMEOUT_MS;
570         chip->timeout_c = TIS_SHORT_TIMEOUT_MS;
571         chip->timeout_d = TIS_SHORT_TIMEOUT_MS;
572
573         chip->locality = LOCALITY0;
574
575         phy->latency = st33zp24_spi_evaluate_latency(dev);
576         if (phy->latency <= 0)
577                 return -ENODEV;
578
579         /*
580          * A timeout query to TPM can be placed here.
581          * Standard timeout values are used so far
582          */
583
584         return 0;
585 }
586
587 static int st33zp24_spi_open(struct udevice *dev)
588 {
589         struct tpm_chip *chip = dev_get_priv(dev);
590         int rc;
591
592         debug("%s: start\n", __func__);
593         if (chip->is_open)
594                 return -EBUSY;
595
596         rc = st33zp24_spi_init(dev);
597         if (rc < 0)
598                 chip->is_open = 0;
599
600         return rc;
601 }
602
603 static int st33zp24_spi_close(struct udevice *dev)
604 {
605         struct tpm_chip *chip = dev_get_priv(dev);
606
607         if (chip->is_open) {
608                 st33zp24_spi_release_locality(dev);
609                 chip->is_open = 0;
610                 chip->vend_dev = 0;
611         }
612
613         return 0;
614 }
615
616 static int st33zp24_spi_get_desc(struct udevice *dev, char *buf, int size)
617 {
618         struct tpm_chip *chip = dev_get_priv(dev);
619
620         if (size < 50)
621                 return -ENOSPC;
622
623         return snprintf(buf, size, "1.2 TPM (%s, chip type %s device-id 0x%x)",
624                         chip->is_open ? "open" : "closed",
625                         dev->name,
626                         chip->vend_dev >> 16);
627 }
628
629 const struct tpm_ops st33zp24_spi_tpm_ops = {
630         .open = st33zp24_spi_open,
631         .close = st33zp24_spi_close,
632         .recv = st33zp24_spi_recv,
633         .send = st33zp24_spi_send,
634         .cleanup = st33zp24_spi_cleanup,
635         .get_desc = st33zp24_spi_get_desc,
636 };
637
638 static int st33zp24_spi_probe(struct udevice *dev)
639 {
640         struct tpm_chip_priv *uc_priv = dev_get_uclass_priv(dev);
641
642         uc_priv->duration_ms[TPM_SHORT] = TIS_SHORT_TIMEOUT_MS;
643         uc_priv->duration_ms[TPM_MEDIUM] = TIS_LONG_TIMEOUT_MS;
644         uc_priv->duration_ms[TPM_LONG] = TIS_LONG_TIMEOUT_MS;
645         uc_priv->retry_time_ms = TPM_TIMEOUT_MS;
646
647         debug("ST33ZP24 SPI TPM from STMicroelectronics found\n");
648
649         return 0;
650 }
651
652 static int st33zp24_spi_remove(struct udevice *dev)
653 {
654         st33zp24_spi_release_locality(dev);
655
656         return 0;
657 }
658
659 static const struct udevice_id st33zp24_spi_ids[] = {
660         { .compatible = "st,st33zp24-spi" },
661         { }
662 };
663
664 U_BOOT_DRIVER(st33zp24_spi_spi) = {
665         .name   = "st33zp24-spi",
666         .id     = UCLASS_TPM,
667         .of_match = of_match_ptr(st33zp24_spi_ids),
668         .probe  = st33zp24_spi_probe,
669         .remove = st33zp24_spi_remove,
670         .ops = &st33zp24_spi_tpm_ops,
671         .priv_auto_alloc_size = sizeof(struct tpm_chip),
672         .platdata_auto_alloc_size = sizeof(struct st33zp24_spi_phy),
673 };