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