xref: /openbmc/linux/drivers/acpi/pfr_update.c (revision de4eda9d)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * ACPI Platform Firmware Runtime Update Device driver
4  *
5  * Copyright (C) 2021 Intel Corporation
6  * Author: Chen Yu <yu.c.chen@intel.com>
7  *
8  * pfr_update driver is used for Platform Firmware Runtime
9  * Update, which includes the code injection and driver update.
10  */
11 #include <linux/acpi.h>
12 #include <linux/device.h>
13 #include <linux/efi.h>
14 #include <linux/err.h>
15 #include <linux/errno.h>
16 #include <linux/file.h>
17 #include <linux/fs.h>
18 #include <linux/idr.h>
19 #include <linux/miscdevice.h>
20 #include <linux/module.h>
21 #include <linux/platform_device.h>
22 #include <linux/string.h>
23 #include <linux/uaccess.h>
24 #include <linux/uio.h>
25 #include <linux/uuid.h>
26 
27 #include <uapi/linux/pfrut.h>
28 
29 #define PFRU_FUNC_STANDARD_QUERY	0
30 #define PFRU_FUNC_QUERY_UPDATE_CAP	1
31 #define PFRU_FUNC_QUERY_BUF		2
32 #define PFRU_FUNC_START		3
33 
34 #define PFRU_CODE_INJECT_TYPE	1
35 #define PFRU_DRIVER_UPDATE_TYPE	2
36 
37 #define PFRU_REVID_1		1
38 #define PFRU_REVID_2		2
39 #define PFRU_DEFAULT_REV_ID	PFRU_REVID_1
40 
41 enum cap_index {
42 	CAP_STATUS_IDX = 0,
43 	CAP_UPDATE_IDX = 1,
44 	CAP_CODE_TYPE_IDX = 2,
45 	CAP_FW_VER_IDX = 3,
46 	CAP_CODE_RT_VER_IDX = 4,
47 	CAP_DRV_TYPE_IDX = 5,
48 	CAP_DRV_RT_VER_IDX = 6,
49 	CAP_DRV_SVN_IDX = 7,
50 	CAP_PLAT_ID_IDX = 8,
51 	CAP_OEM_ID_IDX = 9,
52 	CAP_OEM_INFO_IDX = 10,
53 	CAP_NR_IDX
54 };
55 
56 enum buf_index {
57 	BUF_STATUS_IDX = 0,
58 	BUF_EXT_STATUS_IDX = 1,
59 	BUF_ADDR_LOW_IDX = 2,
60 	BUF_ADDR_HI_IDX = 3,
61 	BUF_SIZE_IDX = 4,
62 	BUF_NR_IDX
63 };
64 
65 enum update_index {
66 	UPDATE_STATUS_IDX = 0,
67 	UPDATE_EXT_STATUS_IDX = 1,
68 	UPDATE_AUTH_TIME_LOW_IDX = 2,
69 	UPDATE_AUTH_TIME_HI_IDX = 3,
70 	UPDATE_EXEC_TIME_LOW_IDX = 4,
71 	UPDATE_EXEC_TIME_HI_IDX = 5,
72 	UPDATE_NR_IDX
73 };
74 
75 enum pfru_start_action {
76 	START_STAGE = 0,
77 	START_ACTIVATE = 1,
78 	START_STAGE_ACTIVATE = 2,
79 };
80 
81 struct pfru_device {
82 	u32 rev_id, index;
83 	struct device *parent_dev;
84 	struct miscdevice miscdev;
85 };
86 
87 static DEFINE_IDA(pfru_ida);
88 
89 /*
90  * Manual reference:
91  * https://uefi.org/sites/default/files/resources/Intel_MM_OS_Interface_Spec_Rev100.pdf
92  *
93  * pfru_guid is the parameter for _DSM method
94  */
95 static const guid_t pfru_guid =
96 	GUID_INIT(0xECF9533B, 0x4A3C, 0x4E89, 0x93, 0x9E, 0xC7, 0x71,
97 		  0x12, 0x60, 0x1C, 0x6D);
98 
99 /* pfru_code_inj_guid is the UUID to identify code injection EFI capsule file */
100 static const guid_t pfru_code_inj_guid =
101 	GUID_INIT(0xB2F84B79, 0x7B6E, 0x4E45, 0x88, 0x5F, 0x3F, 0xB9,
102 		  0xBB, 0x18, 0x54, 0x02);
103 
104 /* pfru_drv_update_guid is the UUID to identify driver update EFI capsule file */
105 static const guid_t pfru_drv_update_guid =
106 	GUID_INIT(0x4569DD8C, 0x75F1, 0x429A, 0xA3, 0xD6, 0x24, 0xDE,
107 		  0x80, 0x97, 0xA0, 0xDF);
108 
pfru_valid_revid(u32 id)109 static inline int pfru_valid_revid(u32 id)
110 {
111 	return id == PFRU_REVID_1 || id == PFRU_REVID_2;
112 }
113 
to_pfru_dev(struct file * file)114 static inline struct pfru_device *to_pfru_dev(struct file *file)
115 {
116 	return container_of(file->private_data, struct pfru_device, miscdev);
117 }
118 
query_capability(struct pfru_update_cap_info * cap_hdr,struct pfru_device * pfru_dev)119 static int query_capability(struct pfru_update_cap_info *cap_hdr,
120 			    struct pfru_device *pfru_dev)
121 {
122 	acpi_handle handle = ACPI_HANDLE(pfru_dev->parent_dev);
123 	union acpi_object *out_obj;
124 	int ret = -EINVAL;
125 
126 	out_obj = acpi_evaluate_dsm_typed(handle, &pfru_guid,
127 					  pfru_dev->rev_id,
128 					  PFRU_FUNC_QUERY_UPDATE_CAP,
129 					  NULL, ACPI_TYPE_PACKAGE);
130 	if (!out_obj)
131 		return ret;
132 
133 	if (out_obj->package.count < CAP_NR_IDX ||
134 	    out_obj->package.elements[CAP_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
135 	    out_obj->package.elements[CAP_UPDATE_IDX].type != ACPI_TYPE_INTEGER ||
136 	    out_obj->package.elements[CAP_CODE_TYPE_IDX].type != ACPI_TYPE_BUFFER ||
137 	    out_obj->package.elements[CAP_FW_VER_IDX].type != ACPI_TYPE_INTEGER ||
138 	    out_obj->package.elements[CAP_CODE_RT_VER_IDX].type != ACPI_TYPE_INTEGER ||
139 	    out_obj->package.elements[CAP_DRV_TYPE_IDX].type != ACPI_TYPE_BUFFER ||
140 	    out_obj->package.elements[CAP_DRV_RT_VER_IDX].type != ACPI_TYPE_INTEGER ||
141 	    out_obj->package.elements[CAP_DRV_SVN_IDX].type != ACPI_TYPE_INTEGER ||
142 	    out_obj->package.elements[CAP_PLAT_ID_IDX].type != ACPI_TYPE_BUFFER ||
143 	    out_obj->package.elements[CAP_OEM_ID_IDX].type != ACPI_TYPE_BUFFER ||
144 	    out_obj->package.elements[CAP_OEM_INFO_IDX].type != ACPI_TYPE_BUFFER)
145 		goto free_acpi_buffer;
146 
147 	cap_hdr->status = out_obj->package.elements[CAP_STATUS_IDX].integer.value;
148 	if (cap_hdr->status != DSM_SUCCEED) {
149 		ret = -EBUSY;
150 		dev_dbg(pfru_dev->parent_dev, "Error Status:%d\n", cap_hdr->status);
151 		goto free_acpi_buffer;
152 	}
153 
154 	cap_hdr->update_cap = out_obj->package.elements[CAP_UPDATE_IDX].integer.value;
155 	memcpy(&cap_hdr->code_type,
156 	       out_obj->package.elements[CAP_CODE_TYPE_IDX].buffer.pointer,
157 	       out_obj->package.elements[CAP_CODE_TYPE_IDX].buffer.length);
158 	cap_hdr->fw_version =
159 		out_obj->package.elements[CAP_FW_VER_IDX].integer.value;
160 	cap_hdr->code_rt_version =
161 		out_obj->package.elements[CAP_CODE_RT_VER_IDX].integer.value;
162 	memcpy(&cap_hdr->drv_type,
163 	       out_obj->package.elements[CAP_DRV_TYPE_IDX].buffer.pointer,
164 	       out_obj->package.elements[CAP_DRV_TYPE_IDX].buffer.length);
165 	cap_hdr->drv_rt_version =
166 		out_obj->package.elements[CAP_DRV_RT_VER_IDX].integer.value;
167 	cap_hdr->drv_svn =
168 		out_obj->package.elements[CAP_DRV_SVN_IDX].integer.value;
169 	memcpy(&cap_hdr->platform_id,
170 	       out_obj->package.elements[CAP_PLAT_ID_IDX].buffer.pointer,
171 	       out_obj->package.elements[CAP_PLAT_ID_IDX].buffer.length);
172 	memcpy(&cap_hdr->oem_id,
173 	       out_obj->package.elements[CAP_OEM_ID_IDX].buffer.pointer,
174 	       out_obj->package.elements[CAP_OEM_ID_IDX].buffer.length);
175 	cap_hdr->oem_info_len =
176 		out_obj->package.elements[CAP_OEM_INFO_IDX].buffer.length;
177 
178 	ret = 0;
179 
180 free_acpi_buffer:
181 	ACPI_FREE(out_obj);
182 
183 	return ret;
184 }
185 
query_buffer(struct pfru_com_buf_info * info,struct pfru_device * pfru_dev)186 static int query_buffer(struct pfru_com_buf_info *info,
187 			struct pfru_device *pfru_dev)
188 {
189 	acpi_handle handle = ACPI_HANDLE(pfru_dev->parent_dev);
190 	union acpi_object *out_obj;
191 	int ret = -EINVAL;
192 
193 	out_obj = acpi_evaluate_dsm_typed(handle, &pfru_guid,
194 					  pfru_dev->rev_id, PFRU_FUNC_QUERY_BUF,
195 					  NULL, ACPI_TYPE_PACKAGE);
196 	if (!out_obj)
197 		return ret;
198 
199 	if (out_obj->package.count < BUF_NR_IDX ||
200 	    out_obj->package.elements[BUF_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
201 	    out_obj->package.elements[BUF_EXT_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
202 	    out_obj->package.elements[BUF_ADDR_LOW_IDX].type != ACPI_TYPE_INTEGER ||
203 	    out_obj->package.elements[BUF_ADDR_HI_IDX].type != ACPI_TYPE_INTEGER ||
204 	    out_obj->package.elements[BUF_SIZE_IDX].type != ACPI_TYPE_INTEGER)
205 		goto free_acpi_buffer;
206 
207 	info->status = out_obj->package.elements[BUF_STATUS_IDX].integer.value;
208 	info->ext_status =
209 		out_obj->package.elements[BUF_EXT_STATUS_IDX].integer.value;
210 	if (info->status != DSM_SUCCEED) {
211 		ret = -EBUSY;
212 		dev_dbg(pfru_dev->parent_dev, "Error Status:%d\n", info->status);
213 		dev_dbg(pfru_dev->parent_dev, "Error Extended Status:%d\n", info->ext_status);
214 
215 		goto free_acpi_buffer;
216 	}
217 
218 	info->addr_lo =
219 		out_obj->package.elements[BUF_ADDR_LOW_IDX].integer.value;
220 	info->addr_hi =
221 		out_obj->package.elements[BUF_ADDR_HI_IDX].integer.value;
222 	info->buf_size = out_obj->package.elements[BUF_SIZE_IDX].integer.value;
223 
224 	ret = 0;
225 
226 free_acpi_buffer:
227 	ACPI_FREE(out_obj);
228 
229 	return ret;
230 }
231 
get_image_type(const struct efi_manage_capsule_image_header * img_hdr,struct pfru_device * pfru_dev)232 static int get_image_type(const struct efi_manage_capsule_image_header *img_hdr,
233 			  struct pfru_device *pfru_dev)
234 {
235 	const efi_guid_t *image_type_id = &img_hdr->image_type_id;
236 
237 	/* check whether this is a code injection or driver update */
238 	if (guid_equal(image_type_id, &pfru_code_inj_guid))
239 		return PFRU_CODE_INJECT_TYPE;
240 
241 	if (guid_equal(image_type_id, &pfru_drv_update_guid))
242 		return PFRU_DRIVER_UPDATE_TYPE;
243 
244 	return -EINVAL;
245 }
246 
adjust_efi_size(const struct efi_manage_capsule_image_header * img_hdr,int size)247 static int adjust_efi_size(const struct efi_manage_capsule_image_header *img_hdr,
248 			   int size)
249 {
250 	/*
251 	 * The (u64 hw_ins) was introduced in UEFI spec version 2,
252 	 * and (u64 capsule_support) was introduced in version 3.
253 	 * The size needs to be adjusted accordingly. That is to
254 	 * say, version 1 should subtract the size of hw_ins+capsule_support,
255 	 * and version 2 should sbstract the size of capsule_support.
256 	 */
257 	size += sizeof(struct efi_manage_capsule_image_header);
258 	switch (img_hdr->ver) {
259 	case 1:
260 		return size - 2 * sizeof(u64);
261 
262 	case 2:
263 		return size - sizeof(u64);
264 
265 	default:
266 		/* only support version 1 and 2 */
267 		return -EINVAL;
268 	}
269 }
270 
applicable_image(const void * data,struct pfru_update_cap_info * cap,struct pfru_device * pfru_dev)271 static bool applicable_image(const void *data, struct pfru_update_cap_info *cap,
272 			     struct pfru_device *pfru_dev)
273 {
274 	struct pfru_payload_hdr *payload_hdr;
275 	const efi_capsule_header_t *cap_hdr = data;
276 	const struct efi_manage_capsule_header *m_hdr;
277 	const struct efi_manage_capsule_image_header *m_img_hdr;
278 	const struct efi_image_auth *auth;
279 	int type, size;
280 
281 	/*
282 	 * If the code in the capsule is older than the current
283 	 * firmware code, the update will be rejected by the firmware,
284 	 * so check the version of it upfront without engaging the
285 	 * Management Mode update mechanism which may be costly.
286 	 */
287 	size = cap_hdr->headersize;
288 	m_hdr = data + size;
289 	/*
290 	 * Current data structure size plus variable array indicated
291 	 * by number of (emb_drv_cnt + payload_cnt)
292 	 */
293 	size += offsetof(struct efi_manage_capsule_header, offset_list) +
294 		(m_hdr->emb_drv_cnt + m_hdr->payload_cnt) * sizeof(u64);
295 	m_img_hdr = data + size;
296 
297 	type = get_image_type(m_img_hdr, pfru_dev);
298 	if (type < 0)
299 		return false;
300 
301 	size = adjust_efi_size(m_img_hdr, size);
302 	if (size < 0)
303 		return false;
304 
305 	auth = data + size;
306 	size += sizeof(u64) + auth->auth_info.hdr.len;
307 	payload_hdr = (struct pfru_payload_hdr *)(data + size);
308 
309 	/* finally compare the version */
310 	if (type == PFRU_CODE_INJECT_TYPE)
311 		return payload_hdr->rt_ver >= cap->code_rt_version;
312 
313 	return payload_hdr->rt_ver >= cap->drv_rt_version;
314 }
315 
print_update_debug_info(struct pfru_updated_result * result,struct pfru_device * pfru_dev)316 static void print_update_debug_info(struct pfru_updated_result *result,
317 				    struct pfru_device *pfru_dev)
318 {
319 	dev_dbg(pfru_dev->parent_dev, "Update result:\n");
320 	dev_dbg(pfru_dev->parent_dev, "Authentication Time Low:%lld\n",
321 		result->low_auth_time);
322 	dev_dbg(pfru_dev->parent_dev, "Authentication Time High:%lld\n",
323 		result->high_auth_time);
324 	dev_dbg(pfru_dev->parent_dev, "Execution Time Low:%lld\n",
325 		result->low_exec_time);
326 	dev_dbg(pfru_dev->parent_dev, "Execution Time High:%lld\n",
327 		result->high_exec_time);
328 }
329 
start_update(int action,struct pfru_device * pfru_dev)330 static int start_update(int action, struct pfru_device *pfru_dev)
331 {
332 	union acpi_object *out_obj, in_obj, in_buf;
333 	struct pfru_updated_result update_result;
334 	acpi_handle handle;
335 	int ret = -EINVAL;
336 
337 	memset(&in_obj, 0, sizeof(in_obj));
338 	memset(&in_buf, 0, sizeof(in_buf));
339 	in_obj.type = ACPI_TYPE_PACKAGE;
340 	in_obj.package.count = 1;
341 	in_obj.package.elements = &in_buf;
342 	in_buf.type = ACPI_TYPE_INTEGER;
343 	in_buf.integer.value = action;
344 
345 	handle = ACPI_HANDLE(pfru_dev->parent_dev);
346 	out_obj = acpi_evaluate_dsm_typed(handle, &pfru_guid,
347 					  pfru_dev->rev_id, PFRU_FUNC_START,
348 					  &in_obj, ACPI_TYPE_PACKAGE);
349 	if (!out_obj)
350 		return ret;
351 
352 	if (out_obj->package.count < UPDATE_NR_IDX ||
353 	    out_obj->package.elements[UPDATE_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
354 	    out_obj->package.elements[UPDATE_EXT_STATUS_IDX].type != ACPI_TYPE_INTEGER ||
355 	    out_obj->package.elements[UPDATE_AUTH_TIME_LOW_IDX].type != ACPI_TYPE_INTEGER ||
356 	    out_obj->package.elements[UPDATE_AUTH_TIME_HI_IDX].type != ACPI_TYPE_INTEGER ||
357 	    out_obj->package.elements[UPDATE_EXEC_TIME_LOW_IDX].type != ACPI_TYPE_INTEGER ||
358 	    out_obj->package.elements[UPDATE_EXEC_TIME_HI_IDX].type != ACPI_TYPE_INTEGER)
359 		goto free_acpi_buffer;
360 
361 	update_result.status =
362 		out_obj->package.elements[UPDATE_STATUS_IDX].integer.value;
363 	update_result.ext_status =
364 		out_obj->package.elements[UPDATE_EXT_STATUS_IDX].integer.value;
365 
366 	if (update_result.status != DSM_SUCCEED) {
367 		ret = -EBUSY;
368 		dev_dbg(pfru_dev->parent_dev, "Error Status:%d\n", update_result.status);
369 		dev_dbg(pfru_dev->parent_dev, "Error Extended Status:%d\n",
370 			update_result.ext_status);
371 
372 		goto free_acpi_buffer;
373 	}
374 
375 	update_result.low_auth_time =
376 		out_obj->package.elements[UPDATE_AUTH_TIME_LOW_IDX].integer.value;
377 	update_result.high_auth_time =
378 		out_obj->package.elements[UPDATE_AUTH_TIME_HI_IDX].integer.value;
379 	update_result.low_exec_time =
380 		out_obj->package.elements[UPDATE_EXEC_TIME_LOW_IDX].integer.value;
381 	update_result.high_exec_time =
382 		out_obj->package.elements[UPDATE_EXEC_TIME_HI_IDX].integer.value;
383 
384 	print_update_debug_info(&update_result, pfru_dev);
385 	ret = 0;
386 
387 free_acpi_buffer:
388 	ACPI_FREE(out_obj);
389 
390 	return ret;
391 }
392 
pfru_ioctl(struct file * file,unsigned int cmd,unsigned long arg)393 static long pfru_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
394 {
395 	struct pfru_update_cap_info cap_hdr;
396 	struct pfru_device *pfru_dev = to_pfru_dev(file);
397 	void __user *p = (void __user *)arg;
398 	u32 rev;
399 	int ret;
400 
401 	switch (cmd) {
402 	case PFRU_IOC_QUERY_CAP:
403 		ret = query_capability(&cap_hdr, pfru_dev);
404 		if (ret)
405 			return ret;
406 
407 		if (copy_to_user(p, &cap_hdr, sizeof(cap_hdr)))
408 			return -EFAULT;
409 
410 		return 0;
411 
412 	case PFRU_IOC_SET_REV:
413 		if (copy_from_user(&rev, p, sizeof(rev)))
414 			return -EFAULT;
415 
416 		if (!pfru_valid_revid(rev))
417 			return -EINVAL;
418 
419 		pfru_dev->rev_id = rev;
420 
421 		return 0;
422 
423 	case PFRU_IOC_STAGE:
424 		return start_update(START_STAGE, pfru_dev);
425 
426 	case PFRU_IOC_ACTIVATE:
427 		return start_update(START_ACTIVATE, pfru_dev);
428 
429 	case PFRU_IOC_STAGE_ACTIVATE:
430 		return start_update(START_STAGE_ACTIVATE, pfru_dev);
431 
432 	default:
433 		return -ENOTTY;
434 	}
435 }
436 
pfru_write(struct file * file,const char __user * buf,size_t len,loff_t * ppos)437 static ssize_t pfru_write(struct file *file, const char __user *buf,
438 			  size_t len, loff_t *ppos)
439 {
440 	struct pfru_device *pfru_dev = to_pfru_dev(file);
441 	struct pfru_update_cap_info cap;
442 	struct pfru_com_buf_info buf_info;
443 	phys_addr_t phy_addr;
444 	struct iov_iter iter;
445 	struct iovec iov;
446 	char *buf_ptr;
447 	int ret;
448 
449 	ret = query_buffer(&buf_info, pfru_dev);
450 	if (ret)
451 		return ret;
452 
453 	if (len > buf_info.buf_size)
454 		return -EINVAL;
455 
456 	iov.iov_base = (void __user *)buf;
457 	iov.iov_len = len;
458 	iov_iter_init(&iter, ITER_SOURCE, &iov, 1, len);
459 
460 	/* map the communication buffer */
461 	phy_addr = (phys_addr_t)((buf_info.addr_hi << 32) | buf_info.addr_lo);
462 	buf_ptr = memremap(phy_addr, buf_info.buf_size, MEMREMAP_WB);
463 	if (!buf_ptr)
464 		return -ENOMEM;
465 
466 	if (!copy_from_iter_full(buf_ptr, len, &iter)) {
467 		ret = -EINVAL;
468 		goto unmap;
469 	}
470 
471 	/* check if the capsule header has a valid version number */
472 	ret = query_capability(&cap, pfru_dev);
473 	if (ret)
474 		goto unmap;
475 
476 	if (!applicable_image(buf_ptr, &cap, pfru_dev))
477 		ret = -EINVAL;
478 
479 unmap:
480 	memunmap(buf_ptr);
481 
482 	return ret ?: len;
483 }
484 
485 static const struct file_operations acpi_pfru_fops = {
486 	.owner		= THIS_MODULE,
487 	.write		= pfru_write,
488 	.unlocked_ioctl = pfru_ioctl,
489 	.llseek		= noop_llseek,
490 };
491 
acpi_pfru_remove(struct platform_device * pdev)492 static int acpi_pfru_remove(struct platform_device *pdev)
493 {
494 	struct pfru_device *pfru_dev = platform_get_drvdata(pdev);
495 
496 	misc_deregister(&pfru_dev->miscdev);
497 
498 	return 0;
499 }
500 
pfru_put_idx(void * data)501 static void pfru_put_idx(void *data)
502 {
503 	struct pfru_device *pfru_dev = data;
504 
505 	ida_free(&pfru_ida, pfru_dev->index);
506 }
507 
acpi_pfru_probe(struct platform_device * pdev)508 static int acpi_pfru_probe(struct platform_device *pdev)
509 {
510 	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
511 	struct pfru_device *pfru_dev;
512 	int ret;
513 
514 	if (!acpi_has_method(handle, "_DSM")) {
515 		dev_dbg(&pdev->dev, "Missing _DSM\n");
516 		return -ENODEV;
517 	}
518 
519 	pfru_dev = devm_kzalloc(&pdev->dev, sizeof(*pfru_dev), GFP_KERNEL);
520 	if (!pfru_dev)
521 		return -ENOMEM;
522 
523 	ret = ida_alloc(&pfru_ida, GFP_KERNEL);
524 	if (ret < 0)
525 		return ret;
526 
527 	pfru_dev->index = ret;
528 	ret = devm_add_action_or_reset(&pdev->dev, pfru_put_idx, pfru_dev);
529 	if (ret)
530 		return ret;
531 
532 	pfru_dev->rev_id = PFRU_DEFAULT_REV_ID;
533 	pfru_dev->parent_dev = &pdev->dev;
534 
535 	pfru_dev->miscdev.minor = MISC_DYNAMIC_MINOR;
536 	pfru_dev->miscdev.name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
537 						"pfru%d", pfru_dev->index);
538 	if (!pfru_dev->miscdev.name)
539 		return -ENOMEM;
540 
541 	pfru_dev->miscdev.nodename = devm_kasprintf(&pdev->dev, GFP_KERNEL,
542 						    "acpi_pfr_update%d", pfru_dev->index);
543 	if (!pfru_dev->miscdev.nodename)
544 		return -ENOMEM;
545 
546 	pfru_dev->miscdev.fops = &acpi_pfru_fops;
547 	pfru_dev->miscdev.parent = &pdev->dev;
548 
549 	ret = misc_register(&pfru_dev->miscdev);
550 	if (ret)
551 		return ret;
552 
553 	platform_set_drvdata(pdev, pfru_dev);
554 
555 	return 0;
556 }
557 
558 static const struct acpi_device_id acpi_pfru_ids[] = {
559 	{"INTC1080"},
560 	{}
561 };
562 MODULE_DEVICE_TABLE(acpi, acpi_pfru_ids);
563 
564 static struct platform_driver acpi_pfru_driver = {
565 	.driver = {
566 		.name = "pfr_update",
567 		.acpi_match_table = acpi_pfru_ids,
568 	},
569 	.probe = acpi_pfru_probe,
570 	.remove = acpi_pfru_remove,
571 };
572 module_platform_driver(acpi_pfru_driver);
573 
574 MODULE_DESCRIPTION("Platform Firmware Runtime Update device driver");
575 MODULE_LICENSE("GPL v2");
576