xref: /openbmc/linux/drivers/char/tpm/tpm_crb.c (revision e2c75e76)
1 /*
2  * Copyright (C) 2014 Intel Corporation
3  *
4  * Authors:
5  * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
6  *
7  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
8  *
9  * This device driver implements the TPM interface as defined in
10  * the TCG CRB 2.0 TPM specification.
11  *
12  * This program is free software; you can redistribute it and/or
13  * modify it under the terms of the GNU General Public License
14  * as published by the Free Software Foundation; version 2
15  * of the License.
16  */
17 
18 #include <linux/acpi.h>
19 #include <linux/highmem.h>
20 #include <linux/rculist.h>
21 #include <linux/module.h>
22 #include <linux/pm_runtime.h>
23 #ifdef CONFIG_ARM64
24 #include <linux/arm-smccc.h>
25 #endif
26 #include "tpm.h"
27 
28 #define ACPI_SIG_TPM2 "TPM2"
29 
30 static const guid_t crb_acpi_start_guid =
31 	GUID_INIT(0x6BBF6CAB, 0x5463, 0x4714,
32 		  0xB7, 0xCD, 0xF0, 0x20, 0x3C, 0x03, 0x68, 0xD4);
33 
34 enum crb_defaults {
35 	CRB_ACPI_START_REVISION_ID = 1,
36 	CRB_ACPI_START_INDEX = 1,
37 };
38 
39 enum crb_loc_ctrl {
40 	CRB_LOC_CTRL_REQUEST_ACCESS	= BIT(0),
41 	CRB_LOC_CTRL_RELINQUISH		= BIT(1),
42 };
43 
44 enum crb_loc_state {
45 	CRB_LOC_STATE_LOC_ASSIGNED	= BIT(1),
46 	CRB_LOC_STATE_TPM_REG_VALID_STS	= BIT(7),
47 };
48 
49 enum crb_ctrl_req {
50 	CRB_CTRL_REQ_CMD_READY	= BIT(0),
51 	CRB_CTRL_REQ_GO_IDLE	= BIT(1),
52 };
53 
54 enum crb_ctrl_sts {
55 	CRB_CTRL_STS_ERROR	= BIT(0),
56 	CRB_CTRL_STS_TPM_IDLE	= BIT(1),
57 };
58 
59 enum crb_start {
60 	CRB_START_INVOKE	= BIT(0),
61 };
62 
63 enum crb_cancel {
64 	CRB_CANCEL_INVOKE	= BIT(0),
65 };
66 
67 struct crb_regs_head {
68 	u32 loc_state;
69 	u32 reserved1;
70 	u32 loc_ctrl;
71 	u32 loc_sts;
72 	u8 reserved2[32];
73 	u64 intf_id;
74 	u64 ctrl_ext;
75 } __packed;
76 
77 struct crb_regs_tail {
78 	u32 ctrl_req;
79 	u32 ctrl_sts;
80 	u32 ctrl_cancel;
81 	u32 ctrl_start;
82 	u32 ctrl_int_enable;
83 	u32 ctrl_int_sts;
84 	u32 ctrl_cmd_size;
85 	u32 ctrl_cmd_pa_low;
86 	u32 ctrl_cmd_pa_high;
87 	u32 ctrl_rsp_size;
88 	u64 ctrl_rsp_pa;
89 } __packed;
90 
91 enum crb_status {
92 	CRB_DRV_STS_COMPLETE	= BIT(0),
93 };
94 
95 struct crb_priv {
96 	u32 sm;
97 	const char *hid;
98 	void __iomem *iobase;
99 	struct crb_regs_head __iomem *regs_h;
100 	struct crb_regs_tail __iomem *regs_t;
101 	u8 __iomem *cmd;
102 	u8 __iomem *rsp;
103 	u32 cmd_size;
104 	u32 smc_func_id;
105 };
106 
107 struct tpm2_crb_smc {
108 	u32 interrupt;
109 	u8 interrupt_flags;
110 	u8 op_flags;
111 	u16 reserved2;
112 	u32 smc_func_id;
113 };
114 
115 /**
116  * crb_go_idle - request tpm crb device to go the idle state
117  *
118  * @dev:  crb device
119  * @priv: crb private data
120  *
121  * Write CRB_CTRL_REQ_GO_IDLE to TPM_CRB_CTRL_REQ
122  * The device should respond within TIMEOUT_C by clearing the bit.
123  * Anyhow, we do not wait here as a consequent CMD_READY request
124  * will be handled correctly even if idle was not completed.
125  *
126  * The function does nothing for devices with ACPI-start method
127  * or SMC-start method.
128  *
129  * Return: 0 always
130  */
131 static int __maybe_unused crb_go_idle(struct device *dev, struct crb_priv *priv)
132 {
133 	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
134 	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
135 	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC))
136 		return 0;
137 
138 	iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->regs_t->ctrl_req);
139 	/* we don't really care when this settles */
140 
141 	return 0;
142 }
143 
144 static bool crb_wait_for_reg_32(u32 __iomem *reg, u32 mask, u32 value,
145 				unsigned long timeout)
146 {
147 	ktime_t start;
148 	ktime_t stop;
149 
150 	start = ktime_get();
151 	stop = ktime_add(start, ms_to_ktime(timeout));
152 
153 	do {
154 		if ((ioread32(reg) & mask) == value)
155 			return true;
156 
157 		usleep_range(50, 100);
158 	} while (ktime_before(ktime_get(), stop));
159 
160 	return false;
161 }
162 
163 /**
164  * crb_cmd_ready - request tpm crb device to enter ready state
165  *
166  * @dev:  crb device
167  * @priv: crb private data
168  *
169  * Write CRB_CTRL_REQ_CMD_READY to TPM_CRB_CTRL_REQ
170  * and poll till the device acknowledge it by clearing the bit.
171  * The device should respond within TIMEOUT_C.
172  *
173  * The function does nothing for devices with ACPI-start method
174  * or SMC-start method.
175  *
176  * Return: 0 on success -ETIME on timeout;
177  */
178 static int __maybe_unused crb_cmd_ready(struct device *dev,
179 					struct crb_priv *priv)
180 {
181 	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
182 	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD) ||
183 	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC))
184 		return 0;
185 
186 	iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->regs_t->ctrl_req);
187 	if (!crb_wait_for_reg_32(&priv->regs_t->ctrl_req,
188 				 CRB_CTRL_REQ_CMD_READY /* mask */,
189 				 0, /* value */
190 				 TPM2_TIMEOUT_C)) {
191 		dev_warn(dev, "cmdReady timed out\n");
192 		return -ETIME;
193 	}
194 
195 	return 0;
196 }
197 
198 static int crb_request_locality(struct tpm_chip *chip, int loc)
199 {
200 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
201 	u32 value = CRB_LOC_STATE_LOC_ASSIGNED |
202 		CRB_LOC_STATE_TPM_REG_VALID_STS;
203 
204 	if (!priv->regs_h)
205 		return 0;
206 
207 	iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);
208 	if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, value, value,
209 				 TPM2_TIMEOUT_C)) {
210 		dev_warn(&chip->dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
211 		return -ETIME;
212 	}
213 
214 	return 0;
215 }
216 
217 static void crb_relinquish_locality(struct tpm_chip *chip, int loc)
218 {
219 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
220 
221 	if (!priv->regs_h)
222 		return;
223 
224 	iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
225 }
226 
227 static u8 crb_status(struct tpm_chip *chip)
228 {
229 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
230 	u8 sts = 0;
231 
232 	if ((ioread32(&priv->regs_t->ctrl_start) & CRB_START_INVOKE) !=
233 	    CRB_START_INVOKE)
234 		sts |= CRB_DRV_STS_COMPLETE;
235 
236 	return sts;
237 }
238 
239 static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
240 {
241 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
242 	unsigned int expected;
243 
244 	/* sanity check */
245 	if (count < 6)
246 		return -EIO;
247 
248 	if (ioread32(&priv->regs_t->ctrl_sts) & CRB_CTRL_STS_ERROR)
249 		return -EIO;
250 
251 	memcpy_fromio(buf, priv->rsp, 6);
252 	expected = be32_to_cpup((__be32 *) &buf[2]);
253 	if (expected > count || expected < 6)
254 		return -EIO;
255 
256 	memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);
257 
258 	return expected;
259 }
260 
261 static int crb_do_acpi_start(struct tpm_chip *chip)
262 {
263 	union acpi_object *obj;
264 	int rc;
265 
266 	obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
267 				&crb_acpi_start_guid,
268 				CRB_ACPI_START_REVISION_ID,
269 				CRB_ACPI_START_INDEX,
270 				NULL);
271 	if (!obj)
272 		return -ENXIO;
273 	rc = obj->integer.value == 0 ? 0 : -ENXIO;
274 	ACPI_FREE(obj);
275 	return rc;
276 }
277 
278 #ifdef CONFIG_ARM64
279 /*
280  * This is a TPM Command Response Buffer start method that invokes a
281  * Secure Monitor Call to requrest the firmware to execute or cancel
282  * a TPM 2.0 command.
283  */
284 static int tpm_crb_smc_start(struct device *dev, unsigned long func_id)
285 {
286 	struct arm_smccc_res res;
287 
288 	arm_smccc_smc(func_id, 0, 0, 0, 0, 0, 0, 0, &res);
289 	if (res.a0 != 0) {
290 		dev_err(dev,
291 			FW_BUG "tpm_crb_smc_start() returns res.a0 = 0x%lx\n",
292 			res.a0);
293 		return -EIO;
294 	}
295 
296 	return 0;
297 }
298 #else
299 static int tpm_crb_smc_start(struct device *dev, unsigned long func_id)
300 {
301 	dev_err(dev, FW_BUG "tpm_crb: incorrect start method\n");
302 	return -EINVAL;
303 }
304 #endif
305 
306 static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
307 {
308 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
309 	int rc = 0;
310 
311 	/* Zero the cancel register so that the next command will not get
312 	 * canceled.
313 	 */
314 	iowrite32(0, &priv->regs_t->ctrl_cancel);
315 
316 	if (len > priv->cmd_size) {
317 		dev_err(&chip->dev, "invalid command count value %zd %d\n",
318 			len, priv->cmd_size);
319 		return -E2BIG;
320 	}
321 
322 	memcpy_toio(priv->cmd, buf, len);
323 
324 	/* Make sure that cmd is populated before issuing start. */
325 	wmb();
326 
327 	/* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
328 	 * report only ACPI start but in practice seems to require both
329 	 * CRB start, hence invoking CRB start method if hid == MSFT0101.
330 	 */
331 	if ((priv->sm == ACPI_TPM2_COMMAND_BUFFER) ||
332 	    (priv->sm == ACPI_TPM2_MEMORY_MAPPED) ||
333 	    (!strcmp(priv->hid, "MSFT0101")))
334 		iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);
335 
336 	if ((priv->sm == ACPI_TPM2_START_METHOD) ||
337 	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD))
338 		rc = crb_do_acpi_start(chip);
339 
340 	if (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC) {
341 		iowrite32(CRB_START_INVOKE, &priv->regs_t->ctrl_start);
342 		rc = tpm_crb_smc_start(&chip->dev, priv->smc_func_id);
343 	}
344 
345 	return rc;
346 }
347 
348 static void crb_cancel(struct tpm_chip *chip)
349 {
350 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
351 
352 	iowrite32(CRB_CANCEL_INVOKE, &priv->regs_t->ctrl_cancel);
353 
354 	if (((priv->sm == ACPI_TPM2_START_METHOD) ||
355 	    (priv->sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)) &&
356 	     crb_do_acpi_start(chip))
357 		dev_err(&chip->dev, "ACPI Start failed\n");
358 }
359 
360 static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
361 {
362 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
363 	u32 cancel = ioread32(&priv->regs_t->ctrl_cancel);
364 
365 	return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
366 }
367 
368 static const struct tpm_class_ops tpm_crb = {
369 	.flags = TPM_OPS_AUTO_STARTUP,
370 	.status = crb_status,
371 	.recv = crb_recv,
372 	.send = crb_send,
373 	.cancel = crb_cancel,
374 	.req_canceled = crb_req_canceled,
375 	.request_locality = crb_request_locality,
376 	.relinquish_locality = crb_relinquish_locality,
377 	.req_complete_mask = CRB_DRV_STS_COMPLETE,
378 	.req_complete_val = CRB_DRV_STS_COMPLETE,
379 };
380 
381 static int crb_check_resource(struct acpi_resource *ares, void *data)
382 {
383 	struct resource *io_res = data;
384 	struct resource_win win;
385 	struct resource *res = &(win.res);
386 
387 	if (acpi_dev_resource_memory(ares, res) ||
388 	    acpi_dev_resource_address_space(ares, &win)) {
389 		*io_res = *res;
390 		io_res->name = NULL;
391 	}
392 
393 	return 1;
394 }
395 
396 static void __iomem *crb_map_res(struct device *dev, struct crb_priv *priv,
397 				 struct resource *io_res, u64 start, u32 size)
398 {
399 	struct resource new_res = {
400 		.start	= start,
401 		.end	= start + size - 1,
402 		.flags	= IORESOURCE_MEM,
403 	};
404 
405 	/* Detect a 64 bit address on a 32 bit system */
406 	if (start != new_res.start)
407 		return (void __iomem *) ERR_PTR(-EINVAL);
408 
409 	if (!resource_contains(io_res, &new_res))
410 		return devm_ioremap_resource(dev, &new_res);
411 
412 	return priv->iobase + (new_res.start - io_res->start);
413 }
414 
415 /*
416  * Work around broken BIOSs that return inconsistent values from the ACPI
417  * region vs the registers. Trust the ACPI region. Such broken systems
418  * probably cannot send large TPM commands since the buffer will be truncated.
419  */
420 static u64 crb_fixup_cmd_size(struct device *dev, struct resource *io_res,
421 			      u64 start, u64 size)
422 {
423 	if (io_res->start > start || io_res->end < start)
424 		return size;
425 
426 	if (start + size - 1 <= io_res->end)
427 		return size;
428 
429 	dev_err(dev,
430 		FW_BUG "ACPI region does not cover the entire command/response buffer. %pr vs %llx %llx\n",
431 		io_res, start, size);
432 
433 	return io_res->end - start + 1;
434 }
435 
436 static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
437 		      struct acpi_table_tpm2 *buf)
438 {
439 	struct list_head resources;
440 	struct resource io_res;
441 	struct device *dev = &device->dev;
442 	u32 pa_high, pa_low;
443 	u64 cmd_pa;
444 	u32 cmd_size;
445 	u64 rsp_pa;
446 	u32 rsp_size;
447 	int ret;
448 
449 	INIT_LIST_HEAD(&resources);
450 	ret = acpi_dev_get_resources(device, &resources, crb_check_resource,
451 				     &io_res);
452 	if (ret < 0)
453 		return ret;
454 	acpi_dev_free_resource_list(&resources);
455 
456 	if (resource_type(&io_res) != IORESOURCE_MEM) {
457 		dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
458 		return -EINVAL;
459 	}
460 
461 	priv->iobase = devm_ioremap_resource(dev, &io_res);
462 	if (IS_ERR(priv->iobase))
463 		return PTR_ERR(priv->iobase);
464 
465 	/* The ACPI IO region starts at the head area and continues to include
466 	 * the control area, as one nice sane region except for some older
467 	 * stuff that puts the control area outside the ACPI IO region.
468 	 */
469 	if ((priv->sm == ACPI_TPM2_COMMAND_BUFFER) ||
470 	    (priv->sm == ACPI_TPM2_MEMORY_MAPPED)) {
471 		if (buf->control_address == io_res.start +
472 		    sizeof(*priv->regs_h))
473 			priv->regs_h = priv->iobase;
474 		else
475 			dev_warn(dev, FW_BUG "Bad ACPI memory layout");
476 	}
477 
478 	priv->regs_t = crb_map_res(dev, priv, &io_res, buf->control_address,
479 				   sizeof(struct crb_regs_tail));
480 	if (IS_ERR(priv->regs_t))
481 		return PTR_ERR(priv->regs_t);
482 
483 	/*
484 	 * PTT HW bug w/a: wake up the device to access
485 	 * possibly not retained registers.
486 	 */
487 	ret = crb_cmd_ready(dev, priv);
488 	if (ret)
489 		return ret;
490 
491 	pa_high = ioread32(&priv->regs_t->ctrl_cmd_pa_high);
492 	pa_low  = ioread32(&priv->regs_t->ctrl_cmd_pa_low);
493 	cmd_pa = ((u64)pa_high << 32) | pa_low;
494 	cmd_size = crb_fixup_cmd_size(dev, &io_res, cmd_pa,
495 				      ioread32(&priv->regs_t->ctrl_cmd_size));
496 
497 	dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
498 		pa_high, pa_low, cmd_size);
499 
500 	priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
501 	if (IS_ERR(priv->cmd)) {
502 		ret = PTR_ERR(priv->cmd);
503 		goto out;
504 	}
505 
506 	memcpy_fromio(&rsp_pa, &priv->regs_t->ctrl_rsp_pa, 8);
507 	rsp_pa = le64_to_cpu(rsp_pa);
508 	rsp_size = crb_fixup_cmd_size(dev, &io_res, rsp_pa,
509 				      ioread32(&priv->regs_t->ctrl_rsp_size));
510 
511 	if (cmd_pa != rsp_pa) {
512 		priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
513 		ret = PTR_ERR_OR_ZERO(priv->rsp);
514 		goto out;
515 	}
516 
517 	/* According to the PTP specification, overlapping command and response
518 	 * buffer sizes must be identical.
519 	 */
520 	if (cmd_size != rsp_size) {
521 		dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
522 		ret = -EINVAL;
523 		goto out;
524 	}
525 
526 	priv->rsp = priv->cmd;
527 
528 out:
529 	if (!ret)
530 		priv->cmd_size = cmd_size;
531 
532 	crb_go_idle(dev, priv);
533 
534 	return ret;
535 }
536 
537 static int crb_acpi_add(struct acpi_device *device)
538 {
539 	struct acpi_table_tpm2 *buf;
540 	struct crb_priv *priv;
541 	struct tpm_chip *chip;
542 	struct device *dev = &device->dev;
543 	struct tpm2_crb_smc *crb_smc;
544 	acpi_status status;
545 	u32 sm;
546 	int rc;
547 
548 	status = acpi_get_table(ACPI_SIG_TPM2, 1,
549 				(struct acpi_table_header **) &buf);
550 	if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
551 		dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
552 		return -EINVAL;
553 	}
554 
555 	/* Should the FIFO driver handle this? */
556 	sm = buf->start_method;
557 	if (sm == ACPI_TPM2_MEMORY_MAPPED)
558 		return -ENODEV;
559 
560 	priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
561 	if (!priv)
562 		return -ENOMEM;
563 
564 	if (sm == ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC) {
565 		if (buf->header.length < (sizeof(*buf) + sizeof(*crb_smc))) {
566 			dev_err(dev,
567 				FW_BUG "TPM2 ACPI table has wrong size %u for start method type %d\n",
568 				buf->header.length,
569 				ACPI_TPM2_COMMAND_BUFFER_WITH_ARM_SMC);
570 			return -EINVAL;
571 		}
572 		crb_smc = ACPI_ADD_PTR(struct tpm2_crb_smc, buf, sizeof(*buf));
573 		priv->smc_func_id = crb_smc->smc_func_id;
574 	}
575 
576 	priv->sm = sm;
577 	priv->hid = acpi_device_hid(device);
578 
579 	rc = crb_map_io(device, priv, buf);
580 	if (rc)
581 		return rc;
582 
583 	chip = tpmm_chip_alloc(dev, &tpm_crb);
584 	if (IS_ERR(chip))
585 		return PTR_ERR(chip);
586 
587 	dev_set_drvdata(&chip->dev, priv);
588 	chip->acpi_dev_handle = device->handle;
589 	chip->flags = TPM_CHIP_FLAG_TPM2;
590 
591 	rc  = crb_cmd_ready(dev, priv);
592 	if (rc)
593 		return rc;
594 
595 	pm_runtime_get_noresume(dev);
596 	pm_runtime_set_active(dev);
597 	pm_runtime_enable(dev);
598 
599 	rc = tpm_chip_register(chip);
600 	if (rc) {
601 		crb_go_idle(dev, priv);
602 		pm_runtime_put_noidle(dev);
603 		pm_runtime_disable(dev);
604 		return rc;
605 	}
606 
607 	pm_runtime_put(dev);
608 
609 	return 0;
610 }
611 
612 static int crb_acpi_remove(struct acpi_device *device)
613 {
614 	struct device *dev = &device->dev;
615 	struct tpm_chip *chip = dev_get_drvdata(dev);
616 
617 	tpm_chip_unregister(chip);
618 
619 	pm_runtime_disable(dev);
620 
621 	return 0;
622 }
623 
624 static int __maybe_unused crb_pm_runtime_suspend(struct device *dev)
625 {
626 	struct tpm_chip *chip = dev_get_drvdata(dev);
627 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
628 
629 	return crb_go_idle(dev, priv);
630 }
631 
632 static int __maybe_unused crb_pm_runtime_resume(struct device *dev)
633 {
634 	struct tpm_chip *chip = dev_get_drvdata(dev);
635 	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
636 
637 	return crb_cmd_ready(dev, priv);
638 }
639 
640 static int __maybe_unused crb_pm_suspend(struct device *dev)
641 {
642 	int ret;
643 
644 	ret = tpm_pm_suspend(dev);
645 	if (ret)
646 		return ret;
647 
648 	return crb_pm_runtime_suspend(dev);
649 }
650 
651 static int __maybe_unused crb_pm_resume(struct device *dev)
652 {
653 	int ret;
654 
655 	ret = crb_pm_runtime_resume(dev);
656 	if (ret)
657 		return ret;
658 
659 	return tpm_pm_resume(dev);
660 }
661 
662 static const struct dev_pm_ops crb_pm = {
663 	SET_SYSTEM_SLEEP_PM_OPS(crb_pm_suspend, crb_pm_resume)
664 	SET_RUNTIME_PM_OPS(crb_pm_runtime_suspend, crb_pm_runtime_resume, NULL)
665 };
666 
667 static const struct acpi_device_id crb_device_ids[] = {
668 	{"MSFT0101", 0},
669 	{"", 0},
670 };
671 MODULE_DEVICE_TABLE(acpi, crb_device_ids);
672 
673 static struct acpi_driver crb_acpi_driver = {
674 	.name = "tpm_crb",
675 	.ids = crb_device_ids,
676 	.ops = {
677 		.add = crb_acpi_add,
678 		.remove = crb_acpi_remove,
679 	},
680 	.drv = {
681 		.pm = &crb_pm,
682 	},
683 };
684 
685 module_acpi_driver(crb_acpi_driver);
686 MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
687 MODULE_DESCRIPTION("TPM2 Driver");
688 MODULE_VERSION("0.1");
689 MODULE_LICENSE("GPL");
690