1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (C) 2004 IBM Corporation |
4 | * Copyright (C) 2014 Intel Corporation |
5 | * |
6 | * Authors: |
7 | * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> |
8 | * Leendert van Doorn <leendert@watson.ibm.com> |
9 | * Dave Safford <safford@watson.ibm.com> |
10 | * Reiner Sailer <sailer@watson.ibm.com> |
11 | * Kylene Hall <kjhall@us.ibm.com> |
12 | * |
13 | * Maintained by: <tpmdd-devel@lists.sourceforge.net> |
14 | * |
15 | * TPM chip management routines. |
16 | */ |
17 | |
18 | #include <linux/poll.h> |
19 | #include <linux/slab.h> |
20 | #include <linux/mutex.h> |
21 | #include <linux/spinlock.h> |
22 | #include <linux/freezer.h> |
23 | #include <linux/major.h> |
24 | #include <linux/tpm_eventlog.h> |
25 | #include <linux/hw_random.h> |
26 | #include "tpm.h" |
27 | |
28 | DEFINE_IDR(dev_nums_idr); |
29 | static DEFINE_MUTEX(idr_lock); |
30 | |
31 | const struct class tpm_class = { |
32 | .name = "tpm" , |
33 | .shutdown_pre = tpm_class_shutdown, |
34 | }; |
35 | const struct class tpmrm_class = { |
36 | .name = "tpmrm" , |
37 | }; |
38 | dev_t tpm_devt; |
39 | |
40 | static int tpm_request_locality(struct tpm_chip *chip) |
41 | { |
42 | int rc; |
43 | |
44 | if (!chip->ops->request_locality) |
45 | return 0; |
46 | |
47 | rc = chip->ops->request_locality(chip, 0); |
48 | if (rc < 0) |
49 | return rc; |
50 | |
51 | chip->locality = rc; |
52 | return 0; |
53 | } |
54 | |
55 | static void tpm_relinquish_locality(struct tpm_chip *chip) |
56 | { |
57 | int rc; |
58 | |
59 | if (!chip->ops->relinquish_locality) |
60 | return; |
61 | |
62 | rc = chip->ops->relinquish_locality(chip, chip->locality); |
63 | if (rc) |
64 | dev_err(&chip->dev, "%s: : error %d\n" , __func__, rc); |
65 | |
66 | chip->locality = -1; |
67 | } |
68 | |
69 | static int tpm_cmd_ready(struct tpm_chip *chip) |
70 | { |
71 | if (!chip->ops->cmd_ready) |
72 | return 0; |
73 | |
74 | return chip->ops->cmd_ready(chip); |
75 | } |
76 | |
77 | static int tpm_go_idle(struct tpm_chip *chip) |
78 | { |
79 | if (!chip->ops->go_idle) |
80 | return 0; |
81 | |
82 | return chip->ops->go_idle(chip); |
83 | } |
84 | |
85 | static void tpm_clk_enable(struct tpm_chip *chip) |
86 | { |
87 | if (chip->ops->clk_enable) |
88 | chip->ops->clk_enable(chip, true); |
89 | } |
90 | |
91 | static void tpm_clk_disable(struct tpm_chip *chip) |
92 | { |
93 | if (chip->ops->clk_enable) |
94 | chip->ops->clk_enable(chip, false); |
95 | } |
96 | |
97 | /** |
98 | * tpm_chip_start() - power on the TPM |
99 | * @chip: a TPM chip to use |
100 | * |
101 | * Return: |
102 | * * The response length - OK |
103 | * * -errno - A system error |
104 | */ |
105 | int tpm_chip_start(struct tpm_chip *chip) |
106 | { |
107 | int ret; |
108 | |
109 | tpm_clk_enable(chip); |
110 | |
111 | if (chip->locality == -1) { |
112 | ret = tpm_request_locality(chip); |
113 | if (ret) { |
114 | tpm_clk_disable(chip); |
115 | return ret; |
116 | } |
117 | } |
118 | |
119 | ret = tpm_cmd_ready(chip); |
120 | if (ret) { |
121 | tpm_relinquish_locality(chip); |
122 | tpm_clk_disable(chip); |
123 | return ret; |
124 | } |
125 | |
126 | return 0; |
127 | } |
128 | EXPORT_SYMBOL_GPL(tpm_chip_start); |
129 | |
130 | /** |
131 | * tpm_chip_stop() - power off the TPM |
132 | * @chip: a TPM chip to use |
133 | * |
134 | * Return: |
135 | * * The response length - OK |
136 | * * -errno - A system error |
137 | */ |
138 | void tpm_chip_stop(struct tpm_chip *chip) |
139 | { |
140 | tpm_go_idle(chip); |
141 | tpm_relinquish_locality(chip); |
142 | tpm_clk_disable(chip); |
143 | } |
144 | EXPORT_SYMBOL_GPL(tpm_chip_stop); |
145 | |
146 | /** |
147 | * tpm_try_get_ops() - Get a ref to the tpm_chip |
148 | * @chip: Chip to ref |
149 | * |
150 | * The caller must already have some kind of locking to ensure that chip is |
151 | * valid. This function will lock the chip so that the ops member can be |
152 | * accessed safely. The locking prevents tpm_chip_unregister from |
153 | * completing, so it should not be held for long periods. |
154 | * |
155 | * Returns -ERRNO if the chip could not be got. |
156 | */ |
157 | int tpm_try_get_ops(struct tpm_chip *chip) |
158 | { |
159 | int rc = -EIO; |
160 | |
161 | get_device(dev: &chip->dev); |
162 | |
163 | down_read(sem: &chip->ops_sem); |
164 | if (!chip->ops) |
165 | goto out_ops; |
166 | |
167 | mutex_lock(&chip->tpm_mutex); |
168 | rc = tpm_chip_start(chip); |
169 | if (rc) |
170 | goto out_lock; |
171 | |
172 | return 0; |
173 | out_lock: |
174 | mutex_unlock(lock: &chip->tpm_mutex); |
175 | out_ops: |
176 | up_read(sem: &chip->ops_sem); |
177 | put_device(dev: &chip->dev); |
178 | return rc; |
179 | } |
180 | EXPORT_SYMBOL_GPL(tpm_try_get_ops); |
181 | |
182 | /** |
183 | * tpm_put_ops() - Release a ref to the tpm_chip |
184 | * @chip: Chip to put |
185 | * |
186 | * This is the opposite pair to tpm_try_get_ops(). After this returns chip may |
187 | * be kfree'd. |
188 | */ |
189 | void tpm_put_ops(struct tpm_chip *chip) |
190 | { |
191 | tpm_chip_stop(chip); |
192 | mutex_unlock(lock: &chip->tpm_mutex); |
193 | up_read(sem: &chip->ops_sem); |
194 | put_device(dev: &chip->dev); |
195 | } |
196 | EXPORT_SYMBOL_GPL(tpm_put_ops); |
197 | |
198 | /** |
199 | * tpm_default_chip() - find a TPM chip and get a reference to it |
200 | */ |
201 | struct tpm_chip *tpm_default_chip(void) |
202 | { |
203 | struct tpm_chip *chip, *res = NULL; |
204 | int chip_num = 0; |
205 | int chip_prev; |
206 | |
207 | mutex_lock(&idr_lock); |
208 | |
209 | do { |
210 | chip_prev = chip_num; |
211 | chip = idr_get_next(&dev_nums_idr, nextid: &chip_num); |
212 | if (chip) { |
213 | get_device(dev: &chip->dev); |
214 | res = chip; |
215 | break; |
216 | } |
217 | } while (chip_prev != chip_num); |
218 | |
219 | mutex_unlock(lock: &idr_lock); |
220 | |
221 | return res; |
222 | } |
223 | EXPORT_SYMBOL_GPL(tpm_default_chip); |
224 | |
225 | /** |
226 | * tpm_find_get_ops() - find and reserve a TPM chip |
227 | * @chip: a &struct tpm_chip instance, %NULL for the default chip |
228 | * |
229 | * Finds a TPM chip and reserves its class device and operations. The chip must |
230 | * be released with tpm_put_ops() after use. |
231 | * This function is for internal use only. It supports existing TPM callers |
232 | * by accepting NULL, but those callers should be converted to pass in a chip |
233 | * directly. |
234 | * |
235 | * Return: |
236 | * A reserved &struct tpm_chip instance. |
237 | * %NULL if a chip is not found. |
238 | * %NULL if the chip is not available. |
239 | */ |
240 | struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip) |
241 | { |
242 | int rc; |
243 | |
244 | if (chip) { |
245 | if (!tpm_try_get_ops(chip)) |
246 | return chip; |
247 | return NULL; |
248 | } |
249 | |
250 | chip = tpm_default_chip(); |
251 | if (!chip) |
252 | return NULL; |
253 | rc = tpm_try_get_ops(chip); |
254 | /* release additional reference we got from tpm_default_chip() */ |
255 | put_device(dev: &chip->dev); |
256 | if (rc) |
257 | return NULL; |
258 | return chip; |
259 | } |
260 | |
261 | /** |
262 | * tpm_dev_release() - free chip memory and the device number |
263 | * @dev: the character device for the TPM chip |
264 | * |
265 | * This is used as the release function for the character device. |
266 | */ |
267 | static void tpm_dev_release(struct device *dev) |
268 | { |
269 | struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev); |
270 | |
271 | mutex_lock(&idr_lock); |
272 | idr_remove(&dev_nums_idr, id: chip->dev_num); |
273 | mutex_unlock(lock: &idr_lock); |
274 | |
275 | kfree(objp: chip->work_space.context_buf); |
276 | kfree(objp: chip->work_space.session_buf); |
277 | kfree(objp: chip->allocated_banks); |
278 | kfree(objp: chip); |
279 | } |
280 | |
281 | /** |
282 | * tpm_class_shutdown() - prepare the TPM device for loss of power. |
283 | * @dev: device to which the chip is associated. |
284 | * |
285 | * Issues a TPM2_Shutdown command prior to loss of power, as required by the |
286 | * TPM 2.0 spec. Then, calls bus- and device- specific shutdown code. |
287 | * |
288 | * Return: always 0 (i.e. success) |
289 | */ |
290 | int tpm_class_shutdown(struct device *dev) |
291 | { |
292 | struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev); |
293 | |
294 | down_write(sem: &chip->ops_sem); |
295 | if (chip->flags & TPM_CHIP_FLAG_TPM2) { |
296 | if (!tpm_chip_start(chip)) { |
297 | tpm2_shutdown(chip, shutdown_type: TPM2_SU_CLEAR); |
298 | tpm_chip_stop(chip); |
299 | } |
300 | } |
301 | chip->ops = NULL; |
302 | up_write(sem: &chip->ops_sem); |
303 | |
304 | return 0; |
305 | } |
306 | |
307 | /** |
308 | * tpm_chip_alloc() - allocate a new struct tpm_chip instance |
309 | * @pdev: device to which the chip is associated |
310 | * At this point pdev mst be initialized, but does not have to |
311 | * be registered |
312 | * @ops: struct tpm_class_ops instance |
313 | * |
314 | * Allocates a new struct tpm_chip instance and assigns a free |
315 | * device number for it. Must be paired with put_device(&chip->dev). |
316 | */ |
317 | struct tpm_chip *tpm_chip_alloc(struct device *pdev, |
318 | const struct tpm_class_ops *ops) |
319 | { |
320 | struct tpm_chip *chip; |
321 | int rc; |
322 | |
323 | chip = kzalloc(size: sizeof(*chip), GFP_KERNEL); |
324 | if (chip == NULL) |
325 | return ERR_PTR(error: -ENOMEM); |
326 | |
327 | mutex_init(&chip->tpm_mutex); |
328 | init_rwsem(&chip->ops_sem); |
329 | |
330 | chip->ops = ops; |
331 | |
332 | mutex_lock(&idr_lock); |
333 | rc = idr_alloc(&dev_nums_idr, NULL, start: 0, TPM_NUM_DEVICES, GFP_KERNEL); |
334 | mutex_unlock(lock: &idr_lock); |
335 | if (rc < 0) { |
336 | dev_err(pdev, "No available tpm device numbers\n" ); |
337 | kfree(objp: chip); |
338 | return ERR_PTR(error: rc); |
339 | } |
340 | chip->dev_num = rc; |
341 | |
342 | device_initialize(dev: &chip->dev); |
343 | |
344 | chip->dev.class = &tpm_class; |
345 | chip->dev.release = tpm_dev_release; |
346 | chip->dev.parent = pdev; |
347 | chip->dev.groups = chip->groups; |
348 | |
349 | if (chip->dev_num == 0) |
350 | chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR); |
351 | else |
352 | chip->dev.devt = MKDEV(MAJOR(tpm_devt), chip->dev_num); |
353 | |
354 | rc = dev_set_name(dev: &chip->dev, name: "tpm%d" , chip->dev_num); |
355 | if (rc) |
356 | goto out; |
357 | |
358 | if (!pdev) |
359 | chip->flags |= TPM_CHIP_FLAG_VIRTUAL; |
360 | |
361 | cdev_init(&chip->cdev, &tpm_fops); |
362 | chip->cdev.owner = THIS_MODULE; |
363 | |
364 | rc = tpm2_init_space(space: &chip->work_space, TPM2_SPACE_BUFFER_SIZE); |
365 | if (rc) { |
366 | rc = -ENOMEM; |
367 | goto out; |
368 | } |
369 | |
370 | chip->locality = -1; |
371 | return chip; |
372 | |
373 | out: |
374 | put_device(dev: &chip->dev); |
375 | return ERR_PTR(error: rc); |
376 | } |
377 | EXPORT_SYMBOL_GPL(tpm_chip_alloc); |
378 | |
379 | static void tpm_put_device(void *dev) |
380 | { |
381 | put_device(dev); |
382 | } |
383 | |
384 | /** |
385 | * tpmm_chip_alloc() - allocate a new struct tpm_chip instance |
386 | * @pdev: parent device to which the chip is associated |
387 | * @ops: struct tpm_class_ops instance |
388 | * |
389 | * Same as tpm_chip_alloc except devm is used to do the put_device |
390 | */ |
391 | struct tpm_chip *tpmm_chip_alloc(struct device *pdev, |
392 | const struct tpm_class_ops *ops) |
393 | { |
394 | struct tpm_chip *chip; |
395 | int rc; |
396 | |
397 | chip = tpm_chip_alloc(pdev, ops); |
398 | if (IS_ERR(ptr: chip)) |
399 | return chip; |
400 | |
401 | rc = devm_add_action_or_reset(pdev, |
402 | tpm_put_device, |
403 | &chip->dev); |
404 | if (rc) |
405 | return ERR_PTR(error: rc); |
406 | |
407 | dev_set_drvdata(dev: pdev, data: chip); |
408 | |
409 | return chip; |
410 | } |
411 | EXPORT_SYMBOL_GPL(tpmm_chip_alloc); |
412 | |
413 | static int tpm_add_char_device(struct tpm_chip *chip) |
414 | { |
415 | int rc; |
416 | |
417 | rc = cdev_device_add(cdev: &chip->cdev, dev: &chip->dev); |
418 | if (rc) { |
419 | dev_err(&chip->dev, |
420 | "unable to cdev_device_add() %s, major %d, minor %d, err=%d\n" , |
421 | dev_name(&chip->dev), MAJOR(chip->dev.devt), |
422 | MINOR(chip->dev.devt), rc); |
423 | return rc; |
424 | } |
425 | |
426 | if (chip->flags & TPM_CHIP_FLAG_TPM2 && !tpm_is_firmware_upgrade(chip)) { |
427 | rc = tpm_devs_add(chip); |
428 | if (rc) |
429 | goto err_del_cdev; |
430 | } |
431 | |
432 | /* Make the chip available. */ |
433 | mutex_lock(&idr_lock); |
434 | idr_replace(&dev_nums_idr, chip, id: chip->dev_num); |
435 | mutex_unlock(lock: &idr_lock); |
436 | |
437 | return 0; |
438 | |
439 | err_del_cdev: |
440 | cdev_device_del(cdev: &chip->cdev, dev: &chip->dev); |
441 | return rc; |
442 | } |
443 | |
444 | static void tpm_del_char_device(struct tpm_chip *chip) |
445 | { |
446 | cdev_device_del(cdev: &chip->cdev, dev: &chip->dev); |
447 | |
448 | /* Make the chip unavailable. */ |
449 | mutex_lock(&idr_lock); |
450 | idr_replace(&dev_nums_idr, NULL, id: chip->dev_num); |
451 | mutex_unlock(lock: &idr_lock); |
452 | |
453 | /* Make the driver uncallable. */ |
454 | down_write(sem: &chip->ops_sem); |
455 | |
456 | /* |
457 | * Check if chip->ops is still valid: In case that the controller |
458 | * drivers shutdown handler unregisters the controller in its |
459 | * shutdown handler we are called twice and chip->ops to NULL. |
460 | */ |
461 | if (chip->ops) { |
462 | if (chip->flags & TPM_CHIP_FLAG_TPM2) { |
463 | if (!tpm_chip_start(chip)) { |
464 | tpm2_shutdown(chip, shutdown_type: TPM2_SU_CLEAR); |
465 | tpm_chip_stop(chip); |
466 | } |
467 | } |
468 | chip->ops = NULL; |
469 | } |
470 | up_write(sem: &chip->ops_sem); |
471 | } |
472 | |
473 | static void tpm_del_legacy_sysfs(struct tpm_chip *chip) |
474 | { |
475 | struct attribute **i; |
476 | |
477 | if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL) || |
478 | tpm_is_firmware_upgrade(chip)) |
479 | return; |
480 | |
481 | sysfs_remove_link(kobj: &chip->dev.parent->kobj, name: "ppi" ); |
482 | |
483 | for (i = chip->groups[0]->attrs; *i != NULL; ++i) |
484 | sysfs_remove_link(kobj: &chip->dev.parent->kobj, name: (*i)->name); |
485 | } |
486 | |
487 | /* For compatibility with legacy sysfs paths we provide symlinks from the |
488 | * parent dev directory to selected names within the tpm chip directory. Old |
489 | * kernel versions created these files directly under the parent. |
490 | */ |
491 | static int tpm_add_legacy_sysfs(struct tpm_chip *chip) |
492 | { |
493 | struct attribute **i; |
494 | int rc; |
495 | |
496 | if (chip->flags & (TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_VIRTUAL) || |
497 | tpm_is_firmware_upgrade(chip)) |
498 | return 0; |
499 | |
500 | rc = compat_only_sysfs_link_entry_to_kobj( |
501 | kobj: &chip->dev.parent->kobj, target_kobj: &chip->dev.kobj, target_name: "ppi" , NULL); |
502 | if (rc && rc != -ENOENT) |
503 | return rc; |
504 | |
505 | /* All the names from tpm-sysfs */ |
506 | for (i = chip->groups[0]->attrs; *i != NULL; ++i) { |
507 | rc = compat_only_sysfs_link_entry_to_kobj( |
508 | kobj: &chip->dev.parent->kobj, target_kobj: &chip->dev.kobj, target_name: (*i)->name, NULL); |
509 | if (rc) { |
510 | tpm_del_legacy_sysfs(chip); |
511 | return rc; |
512 | } |
513 | } |
514 | |
515 | return 0; |
516 | } |
517 | |
518 | static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait) |
519 | { |
520 | struct tpm_chip *chip = container_of(rng, struct tpm_chip, hwrng); |
521 | |
522 | /* Give back zero bytes, as TPM chip has not yet fully resumed: */ |
523 | if (chip->flags & TPM_CHIP_FLAG_SUSPENDED) |
524 | return 0; |
525 | |
526 | return tpm_get_random(chip, data, max); |
527 | } |
528 | |
529 | static bool tpm_is_hwrng_enabled(struct tpm_chip *chip) |
530 | { |
531 | if (!IS_ENABLED(CONFIG_HW_RANDOM_TPM)) |
532 | return false; |
533 | if (tpm_is_firmware_upgrade(chip)) |
534 | return false; |
535 | if (chip->flags & TPM_CHIP_FLAG_HWRNG_DISABLED) |
536 | return false; |
537 | return true; |
538 | } |
539 | |
540 | static int tpm_add_hwrng(struct tpm_chip *chip) |
541 | { |
542 | if (!tpm_is_hwrng_enabled(chip)) |
543 | return 0; |
544 | |
545 | snprintf(buf: chip->hwrng_name, size: sizeof(chip->hwrng_name), |
546 | fmt: "tpm-rng-%d" , chip->dev_num); |
547 | chip->hwrng.name = chip->hwrng_name; |
548 | chip->hwrng.read = tpm_hwrng_read; |
549 | return hwrng_register(rng: &chip->hwrng); |
550 | } |
551 | |
552 | static int tpm_get_pcr_allocation(struct tpm_chip *chip) |
553 | { |
554 | int rc; |
555 | |
556 | if (tpm_is_firmware_upgrade(chip)) |
557 | return 0; |
558 | |
559 | rc = (chip->flags & TPM_CHIP_FLAG_TPM2) ? |
560 | tpm2_get_pcr_allocation(chip) : |
561 | tpm1_get_pcr_allocation(chip); |
562 | |
563 | if (rc > 0) |
564 | return -ENODEV; |
565 | |
566 | return rc; |
567 | } |
568 | |
569 | /* |
570 | * tpm_chip_bootstrap() - Boostrap TPM chip after power on |
571 | * @chip: TPM chip to use. |
572 | * |
573 | * Initialize TPM chip after power on. This a one-shot function: subsequent |
574 | * calls will have no effect. |
575 | */ |
576 | int tpm_chip_bootstrap(struct tpm_chip *chip) |
577 | { |
578 | int rc; |
579 | |
580 | if (chip->flags & TPM_CHIP_FLAG_BOOTSTRAPPED) |
581 | return 0; |
582 | |
583 | rc = tpm_chip_start(chip); |
584 | if (rc) |
585 | return rc; |
586 | |
587 | rc = tpm_auto_startup(chip); |
588 | if (rc) |
589 | goto stop; |
590 | |
591 | rc = tpm_get_pcr_allocation(chip); |
592 | stop: |
593 | tpm_chip_stop(chip); |
594 | |
595 | /* |
596 | * Unconditionally set, as driver initialization should cease, when the |
597 | * boostrapping process fails. |
598 | */ |
599 | chip->flags |= TPM_CHIP_FLAG_BOOTSTRAPPED; |
600 | |
601 | return rc; |
602 | } |
603 | EXPORT_SYMBOL_GPL(tpm_chip_bootstrap); |
604 | |
605 | /* |
606 | * tpm_chip_register() - create a character device for the TPM chip |
607 | * @chip: TPM chip to use. |
608 | * |
609 | * Creates a character device for the TPM chip and adds sysfs attributes for |
610 | * the device. As the last step this function adds the chip to the list of TPM |
611 | * chips available for in-kernel use. |
612 | * |
613 | * This function should be only called after the chip initialization is |
614 | * complete. |
615 | */ |
616 | int tpm_chip_register(struct tpm_chip *chip) |
617 | { |
618 | int rc; |
619 | |
620 | rc = tpm_chip_bootstrap(chip); |
621 | if (rc) |
622 | return rc; |
623 | |
624 | tpm_sysfs_add_device(chip); |
625 | |
626 | tpm_bios_log_setup(chip); |
627 | |
628 | tpm_add_ppi(chip); |
629 | |
630 | rc = tpm_add_hwrng(chip); |
631 | if (rc) |
632 | goto out_ppi; |
633 | |
634 | rc = tpm_add_char_device(chip); |
635 | if (rc) |
636 | goto out_hwrng; |
637 | |
638 | rc = tpm_add_legacy_sysfs(chip); |
639 | if (rc) { |
640 | tpm_chip_unregister(chip); |
641 | return rc; |
642 | } |
643 | |
644 | return 0; |
645 | |
646 | out_hwrng: |
647 | if (tpm_is_hwrng_enabled(chip)) |
648 | hwrng_unregister(rng: &chip->hwrng); |
649 | out_ppi: |
650 | tpm_bios_log_teardown(chip); |
651 | |
652 | return rc; |
653 | } |
654 | EXPORT_SYMBOL_GPL(tpm_chip_register); |
655 | |
656 | /* |
657 | * tpm_chip_unregister() - release the TPM driver |
658 | * @chip: TPM chip to use. |
659 | * |
660 | * Takes the chip first away from the list of available TPM chips and then |
661 | * cleans up all the resources reserved by tpm_chip_register(). |
662 | * |
663 | * Once this function returns the driver call backs in 'op's will not be |
664 | * running and will no longer start. |
665 | * |
666 | * NOTE: This function should be only called before deinitializing chip |
667 | * resources. |
668 | */ |
669 | void tpm_chip_unregister(struct tpm_chip *chip) |
670 | { |
671 | tpm_del_legacy_sysfs(chip); |
672 | if (tpm_is_hwrng_enabled(chip)) |
673 | hwrng_unregister(rng: &chip->hwrng); |
674 | tpm_bios_log_teardown(chip); |
675 | if (chip->flags & TPM_CHIP_FLAG_TPM2 && !tpm_is_firmware_upgrade(chip)) |
676 | tpm_devs_remove(chip); |
677 | tpm_del_char_device(chip); |
678 | } |
679 | EXPORT_SYMBOL_GPL(tpm_chip_unregister); |
680 | |