1 /*
2  * Copyright (C) 2013 - Virtual Open Systems
3  * Author: Antonios Motakis <a.motakis@virtualopensystems.com>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License, version 2, as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  */
14 
15 #include <linux/device.h>
16 #include <linux/acpi.h>
17 #include <linux/iommu.h>
18 #include <linux/module.h>
19 #include <linux/mutex.h>
20 #include <linux/slab.h>
21 #include <linux/types.h>
22 #include <linux/uaccess.h>
23 #include <linux/vfio.h>
24 
25 #include "vfio_platform_private.h"
26 
27 #define DRIVER_VERSION  "0.10"
28 #define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@virtualopensystems.com>"
29 #define DRIVER_DESC     "VFIO platform base module"
30 
31 #define VFIO_PLATFORM_IS_ACPI(vdev) ((vdev)->acpihid != NULL)
32 
33 static LIST_HEAD(reset_list);
34 static DEFINE_MUTEX(driver_lock);
35 
36 static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
37 					struct module **module)
38 {
39 	struct vfio_platform_reset_node *iter;
40 	vfio_platform_reset_fn_t reset_fn = NULL;
41 
42 	mutex_lock(&driver_lock);
43 	list_for_each_entry(iter, &reset_list, link) {
44 		if (!strcmp(iter->compat, compat) &&
45 			try_module_get(iter->owner)) {
46 			*module = iter->owner;
47 			reset_fn = iter->of_reset;
48 			break;
49 		}
50 	}
51 	mutex_unlock(&driver_lock);
52 	return reset_fn;
53 }
54 
55 static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
56 				    struct device *dev)
57 {
58 	struct acpi_device *adev;
59 
60 	if (acpi_disabled)
61 		return -ENOENT;
62 
63 	adev = ACPI_COMPANION(dev);
64 	if (!adev) {
65 		pr_err("VFIO: ACPI companion device not found for %s\n",
66 			vdev->name);
67 		return -ENODEV;
68 	}
69 
70 #ifdef CONFIG_ACPI
71 	vdev->acpihid = acpi_device_hid(adev);
72 #endif
73 	return WARN_ON(!vdev->acpihid) ? -EINVAL : 0;
74 }
75 
76 static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
77 				  const char **extra_dbg)
78 {
79 #ifdef CONFIG_ACPI
80 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
81 	struct device *dev = vdev->device;
82 	acpi_handle handle = ACPI_HANDLE(dev);
83 	acpi_status acpi_ret;
84 
85 	acpi_ret = acpi_evaluate_object(handle, "_RST", NULL, &buffer);
86 	if (ACPI_FAILURE(acpi_ret)) {
87 		if (extra_dbg)
88 			*extra_dbg = acpi_format_exception(acpi_ret);
89 		return -EINVAL;
90 	}
91 
92 	return 0;
93 #else
94 	return -ENOENT;
95 #endif
96 }
97 
98 static bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
99 {
100 #ifdef CONFIG_ACPI
101 	struct device *dev = vdev->device;
102 	acpi_handle handle = ACPI_HANDLE(dev);
103 
104 	return acpi_has_method(handle, "_RST");
105 #else
106 	return false;
107 #endif
108 }
109 
110 static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
111 {
112 	if (VFIO_PLATFORM_IS_ACPI(vdev))
113 		return vfio_platform_acpi_has_reset(vdev);
114 
115 	return vdev->of_reset ? true : false;
116 }
117 
118 static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
119 {
120 	if (VFIO_PLATFORM_IS_ACPI(vdev))
121 		return vfio_platform_acpi_has_reset(vdev) ? 0 : -ENOENT;
122 
123 	vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
124 						    &vdev->reset_module);
125 	if (!vdev->of_reset) {
126 		request_module("vfio-reset:%s", vdev->compat);
127 		vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
128 							&vdev->reset_module);
129 	}
130 
131 	return vdev->of_reset ? 0 : -ENOENT;
132 }
133 
134 static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
135 {
136 	if (VFIO_PLATFORM_IS_ACPI(vdev))
137 		return;
138 
139 	if (vdev->of_reset)
140 		module_put(vdev->reset_module);
141 }
142 
143 static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
144 {
145 	int cnt = 0, i;
146 
147 	while (vdev->get_resource(vdev, cnt))
148 		cnt++;
149 
150 	vdev->regions = kcalloc(cnt, sizeof(struct vfio_platform_region),
151 				GFP_KERNEL);
152 	if (!vdev->regions)
153 		return -ENOMEM;
154 
155 	for (i = 0; i < cnt;  i++) {
156 		struct resource *res =
157 			vdev->get_resource(vdev, i);
158 
159 		if (!res)
160 			goto err;
161 
162 		vdev->regions[i].addr = res->start;
163 		vdev->regions[i].size = resource_size(res);
164 		vdev->regions[i].flags = 0;
165 
166 		switch (resource_type(res)) {
167 		case IORESOURCE_MEM:
168 			vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_MMIO;
169 			vdev->regions[i].flags |= VFIO_REGION_INFO_FLAG_READ;
170 			if (!(res->flags & IORESOURCE_READONLY))
171 				vdev->regions[i].flags |=
172 					VFIO_REGION_INFO_FLAG_WRITE;
173 
174 			/*
175 			 * Only regions addressed with PAGE granularity may be
176 			 * MMAPed securely.
177 			 */
178 			if (!(vdev->regions[i].addr & ~PAGE_MASK) &&
179 					!(vdev->regions[i].size & ~PAGE_MASK))
180 				vdev->regions[i].flags |=
181 					VFIO_REGION_INFO_FLAG_MMAP;
182 
183 			break;
184 		case IORESOURCE_IO:
185 			vdev->regions[i].type = VFIO_PLATFORM_REGION_TYPE_PIO;
186 			break;
187 		default:
188 			goto err;
189 		}
190 	}
191 
192 	vdev->num_regions = cnt;
193 
194 	return 0;
195 err:
196 	kfree(vdev->regions);
197 	return -EINVAL;
198 }
199 
200 static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev)
201 {
202 	int i;
203 
204 	for (i = 0; i < vdev->num_regions; i++)
205 		iounmap(vdev->regions[i].ioaddr);
206 
207 	vdev->num_regions = 0;
208 	kfree(vdev->regions);
209 }
210 
211 static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
212 				    const char **extra_dbg)
213 {
214 	if (VFIO_PLATFORM_IS_ACPI(vdev)) {
215 		dev_info(vdev->device, "reset\n");
216 		return vfio_platform_acpi_call_reset(vdev, extra_dbg);
217 	} else if (vdev->of_reset) {
218 		dev_info(vdev->device, "reset\n");
219 		return vdev->of_reset(vdev);
220 	}
221 
222 	dev_warn(vdev->device, "no reset function found!\n");
223 	return -EINVAL;
224 }
225 
226 static void vfio_platform_release(void *device_data)
227 {
228 	struct vfio_platform_device *vdev = device_data;
229 
230 	mutex_lock(&driver_lock);
231 
232 	if (!(--vdev->refcnt)) {
233 		const char *extra_dbg = NULL;
234 		int ret;
235 
236 		ret = vfio_platform_call_reset(vdev, &extra_dbg);
237 		if (ret && vdev->reset_required) {
238 			dev_warn(vdev->device, "reset driver is required and reset call failed in release (%d) %s\n",
239 				 ret, extra_dbg ? extra_dbg : "");
240 			WARN_ON(1);
241 		}
242 		vfio_platform_regions_cleanup(vdev);
243 		vfio_platform_irq_cleanup(vdev);
244 	}
245 
246 	mutex_unlock(&driver_lock);
247 
248 	module_put(vdev->parent_module);
249 }
250 
251 static int vfio_platform_open(void *device_data)
252 {
253 	struct vfio_platform_device *vdev = device_data;
254 	int ret;
255 
256 	if (!try_module_get(vdev->parent_module))
257 		return -ENODEV;
258 
259 	mutex_lock(&driver_lock);
260 
261 	if (!vdev->refcnt) {
262 		const char *extra_dbg = NULL;
263 
264 		ret = vfio_platform_regions_init(vdev);
265 		if (ret)
266 			goto err_reg;
267 
268 		ret = vfio_platform_irq_init(vdev);
269 		if (ret)
270 			goto err_irq;
271 
272 		ret = vfio_platform_call_reset(vdev, &extra_dbg);
273 		if (ret && vdev->reset_required) {
274 			dev_warn(vdev->device, "reset driver is required and reset call failed in open (%d) %s\n",
275 				 ret, extra_dbg ? extra_dbg : "");
276 			goto err_rst;
277 		}
278 	}
279 
280 	vdev->refcnt++;
281 
282 	mutex_unlock(&driver_lock);
283 	return 0;
284 
285 err_rst:
286 	vfio_platform_irq_cleanup(vdev);
287 err_irq:
288 	vfio_platform_regions_cleanup(vdev);
289 err_reg:
290 	mutex_unlock(&driver_lock);
291 	module_put(THIS_MODULE);
292 	return ret;
293 }
294 
295 static long vfio_platform_ioctl(void *device_data,
296 				unsigned int cmd, unsigned long arg)
297 {
298 	struct vfio_platform_device *vdev = device_data;
299 	unsigned long minsz;
300 
301 	if (cmd == VFIO_DEVICE_GET_INFO) {
302 		struct vfio_device_info info;
303 
304 		minsz = offsetofend(struct vfio_device_info, num_irqs);
305 
306 		if (copy_from_user(&info, (void __user *)arg, minsz))
307 			return -EFAULT;
308 
309 		if (info.argsz < minsz)
310 			return -EINVAL;
311 
312 		if (vfio_platform_has_reset(vdev))
313 			vdev->flags |= VFIO_DEVICE_FLAGS_RESET;
314 		info.flags = vdev->flags;
315 		info.num_regions = vdev->num_regions;
316 		info.num_irqs = vdev->num_irqs;
317 
318 		return copy_to_user((void __user *)arg, &info, minsz) ?
319 			-EFAULT : 0;
320 
321 	} else if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
322 		struct vfio_region_info info;
323 
324 		minsz = offsetofend(struct vfio_region_info, offset);
325 
326 		if (copy_from_user(&info, (void __user *)arg, minsz))
327 			return -EFAULT;
328 
329 		if (info.argsz < minsz)
330 			return -EINVAL;
331 
332 		if (info.index >= vdev->num_regions)
333 			return -EINVAL;
334 
335 		/* map offset to the physical address  */
336 		info.offset = VFIO_PLATFORM_INDEX_TO_OFFSET(info.index);
337 		info.size = vdev->regions[info.index].size;
338 		info.flags = vdev->regions[info.index].flags;
339 
340 		return copy_to_user((void __user *)arg, &info, minsz) ?
341 			-EFAULT : 0;
342 
343 	} else if (cmd == VFIO_DEVICE_GET_IRQ_INFO) {
344 		struct vfio_irq_info info;
345 
346 		minsz = offsetofend(struct vfio_irq_info, count);
347 
348 		if (copy_from_user(&info, (void __user *)arg, minsz))
349 			return -EFAULT;
350 
351 		if (info.argsz < minsz)
352 			return -EINVAL;
353 
354 		if (info.index >= vdev->num_irqs)
355 			return -EINVAL;
356 
357 		info.flags = vdev->irqs[info.index].flags;
358 		info.count = vdev->irqs[info.index].count;
359 
360 		return copy_to_user((void __user *)arg, &info, minsz) ?
361 			-EFAULT : 0;
362 
363 	} else if (cmd == VFIO_DEVICE_SET_IRQS) {
364 		struct vfio_irq_set hdr;
365 		u8 *data = NULL;
366 		int ret = 0;
367 		size_t data_size = 0;
368 
369 		minsz = offsetofend(struct vfio_irq_set, count);
370 
371 		if (copy_from_user(&hdr, (void __user *)arg, minsz))
372 			return -EFAULT;
373 
374 		ret = vfio_set_irqs_validate_and_prepare(&hdr, vdev->num_irqs,
375 						 vdev->num_irqs, &data_size);
376 		if (ret)
377 			return ret;
378 
379 		if (data_size) {
380 			data = memdup_user((void __user *)(arg + minsz),
381 					    data_size);
382 			if (IS_ERR(data))
383 				return PTR_ERR(data);
384 		}
385 
386 		mutex_lock(&vdev->igate);
387 
388 		ret = vfio_platform_set_irqs_ioctl(vdev, hdr.flags, hdr.index,
389 						   hdr.start, hdr.count, data);
390 		mutex_unlock(&vdev->igate);
391 		kfree(data);
392 
393 		return ret;
394 
395 	} else if (cmd == VFIO_DEVICE_RESET) {
396 		return vfio_platform_call_reset(vdev, NULL);
397 	}
398 
399 	return -ENOTTY;
400 }
401 
402 static ssize_t vfio_platform_read_mmio(struct vfio_platform_region *reg,
403 				       char __user *buf, size_t count,
404 				       loff_t off)
405 {
406 	unsigned int done = 0;
407 
408 	if (!reg->ioaddr) {
409 		reg->ioaddr =
410 			ioremap_nocache(reg->addr, reg->size);
411 
412 		if (!reg->ioaddr)
413 			return -ENOMEM;
414 	}
415 
416 	while (count) {
417 		size_t filled;
418 
419 		if (count >= 4 && !(off % 4)) {
420 			u32 val;
421 
422 			val = ioread32(reg->ioaddr + off);
423 			if (copy_to_user(buf, &val, 4))
424 				goto err;
425 
426 			filled = 4;
427 		} else if (count >= 2 && !(off % 2)) {
428 			u16 val;
429 
430 			val = ioread16(reg->ioaddr + off);
431 			if (copy_to_user(buf, &val, 2))
432 				goto err;
433 
434 			filled = 2;
435 		} else {
436 			u8 val;
437 
438 			val = ioread8(reg->ioaddr + off);
439 			if (copy_to_user(buf, &val, 1))
440 				goto err;
441 
442 			filled = 1;
443 		}
444 
445 
446 		count -= filled;
447 		done += filled;
448 		off += filled;
449 		buf += filled;
450 	}
451 
452 	return done;
453 err:
454 	return -EFAULT;
455 }
456 
457 static ssize_t vfio_platform_read(void *device_data, char __user *buf,
458 				  size_t count, loff_t *ppos)
459 {
460 	struct vfio_platform_device *vdev = device_data;
461 	unsigned int index = VFIO_PLATFORM_OFFSET_TO_INDEX(*ppos);
462 	loff_t off = *ppos & VFIO_PLATFORM_OFFSET_MASK;
463 
464 	if (index >= vdev->num_regions)
465 		return -EINVAL;
466 
467 	if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_READ))
468 		return -EINVAL;
469 
470 	if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_MMIO)
471 		return vfio_platform_read_mmio(&vdev->regions[index],
472 							buf, count, off);
473 	else if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_PIO)
474 		return -EINVAL; /* not implemented */
475 
476 	return -EINVAL;
477 }
478 
479 static ssize_t vfio_platform_write_mmio(struct vfio_platform_region *reg,
480 					const char __user *buf, size_t count,
481 					loff_t off)
482 {
483 	unsigned int done = 0;
484 
485 	if (!reg->ioaddr) {
486 		reg->ioaddr =
487 			ioremap_nocache(reg->addr, reg->size);
488 
489 		if (!reg->ioaddr)
490 			return -ENOMEM;
491 	}
492 
493 	while (count) {
494 		size_t filled;
495 
496 		if (count >= 4 && !(off % 4)) {
497 			u32 val;
498 
499 			if (copy_from_user(&val, buf, 4))
500 				goto err;
501 			iowrite32(val, reg->ioaddr + off);
502 
503 			filled = 4;
504 		} else if (count >= 2 && !(off % 2)) {
505 			u16 val;
506 
507 			if (copy_from_user(&val, buf, 2))
508 				goto err;
509 			iowrite16(val, reg->ioaddr + off);
510 
511 			filled = 2;
512 		} else {
513 			u8 val;
514 
515 			if (copy_from_user(&val, buf, 1))
516 				goto err;
517 			iowrite8(val, reg->ioaddr + off);
518 
519 			filled = 1;
520 		}
521 
522 		count -= filled;
523 		done += filled;
524 		off += filled;
525 		buf += filled;
526 	}
527 
528 	return done;
529 err:
530 	return -EFAULT;
531 }
532 
533 static ssize_t vfio_platform_write(void *device_data, const char __user *buf,
534 				   size_t count, loff_t *ppos)
535 {
536 	struct vfio_platform_device *vdev = device_data;
537 	unsigned int index = VFIO_PLATFORM_OFFSET_TO_INDEX(*ppos);
538 	loff_t off = *ppos & VFIO_PLATFORM_OFFSET_MASK;
539 
540 	if (index >= vdev->num_regions)
541 		return -EINVAL;
542 
543 	if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_WRITE))
544 		return -EINVAL;
545 
546 	if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_MMIO)
547 		return vfio_platform_write_mmio(&vdev->regions[index],
548 							buf, count, off);
549 	else if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_PIO)
550 		return -EINVAL; /* not implemented */
551 
552 	return -EINVAL;
553 }
554 
555 static int vfio_platform_mmap_mmio(struct vfio_platform_region region,
556 				   struct vm_area_struct *vma)
557 {
558 	u64 req_len, pgoff, req_start;
559 
560 	req_len = vma->vm_end - vma->vm_start;
561 	pgoff = vma->vm_pgoff &
562 		((1U << (VFIO_PLATFORM_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
563 	req_start = pgoff << PAGE_SHIFT;
564 
565 	if (region.size < PAGE_SIZE || req_start + req_len > region.size)
566 		return -EINVAL;
567 
568 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
569 	vma->vm_pgoff = (region.addr >> PAGE_SHIFT) + pgoff;
570 
571 	return remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
572 			       req_len, vma->vm_page_prot);
573 }
574 
575 static int vfio_platform_mmap(void *device_data, struct vm_area_struct *vma)
576 {
577 	struct vfio_platform_device *vdev = device_data;
578 	unsigned int index;
579 
580 	index = vma->vm_pgoff >> (VFIO_PLATFORM_OFFSET_SHIFT - PAGE_SHIFT);
581 
582 	if (vma->vm_end < vma->vm_start)
583 		return -EINVAL;
584 	if (!(vma->vm_flags & VM_SHARED))
585 		return -EINVAL;
586 	if (index >= vdev->num_regions)
587 		return -EINVAL;
588 	if (vma->vm_start & ~PAGE_MASK)
589 		return -EINVAL;
590 	if (vma->vm_end & ~PAGE_MASK)
591 		return -EINVAL;
592 
593 	if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_MMAP))
594 		return -EINVAL;
595 
596 	if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_READ)
597 			&& (vma->vm_flags & VM_READ))
598 		return -EINVAL;
599 
600 	if (!(vdev->regions[index].flags & VFIO_REGION_INFO_FLAG_WRITE)
601 			&& (vma->vm_flags & VM_WRITE))
602 		return -EINVAL;
603 
604 	vma->vm_private_data = vdev;
605 
606 	if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_MMIO)
607 		return vfio_platform_mmap_mmio(vdev->regions[index], vma);
608 
609 	else if (vdev->regions[index].type & VFIO_PLATFORM_REGION_TYPE_PIO)
610 		return -EINVAL; /* not implemented */
611 
612 	return -EINVAL;
613 }
614 
615 static const struct vfio_device_ops vfio_platform_ops = {
616 	.name		= "vfio-platform",
617 	.open		= vfio_platform_open,
618 	.release	= vfio_platform_release,
619 	.ioctl		= vfio_platform_ioctl,
620 	.read		= vfio_platform_read,
621 	.write		= vfio_platform_write,
622 	.mmap		= vfio_platform_mmap,
623 };
624 
625 static int vfio_platform_of_probe(struct vfio_platform_device *vdev,
626 			   struct device *dev)
627 {
628 	int ret;
629 
630 	ret = device_property_read_string(dev, "compatible",
631 					  &vdev->compat);
632 	if (ret)
633 		pr_err("VFIO: cannot retrieve compat for %s\n",
634 			vdev->name);
635 
636 	return ret;
637 }
638 
639 /*
640  * There can be two kernel build combinations. One build where
641  * ACPI is not selected in Kconfig and another one with the ACPI Kconfig.
642  *
643  * In the first case, vfio_platform_acpi_probe will return since
644  * acpi_disabled is 1. DT user will not see any kind of messages from
645  * ACPI.
646  *
647  * In the second case, both DT and ACPI is compiled in but the system is
648  * booting with any of these combinations.
649  *
650  * If the firmware is DT type, then acpi_disabled is 1. The ACPI probe routine
651  * terminates immediately without any messages.
652  *
653  * If the firmware is ACPI type, then acpi_disabled is 0. All other checks are
654  * valid checks. We cannot claim that this system is DT.
655  */
656 int vfio_platform_probe_common(struct vfio_platform_device *vdev,
657 			       struct device *dev)
658 {
659 	struct iommu_group *group;
660 	int ret;
661 
662 	if (!vdev)
663 		return -EINVAL;
664 
665 	ret = vfio_platform_acpi_probe(vdev, dev);
666 	if (ret)
667 		ret = vfio_platform_of_probe(vdev, dev);
668 
669 	if (ret)
670 		return ret;
671 
672 	vdev->device = dev;
673 
674 	ret = vfio_platform_get_reset(vdev);
675 	if (ret && vdev->reset_required) {
676 		pr_err("vfio: no reset function found for device %s\n",
677 		       vdev->name);
678 		return ret;
679 	}
680 
681 	group = vfio_iommu_group_get(dev);
682 	if (!group) {
683 		pr_err("VFIO: No IOMMU group for device %s\n", vdev->name);
684 		return -EINVAL;
685 	}
686 
687 	ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev);
688 	if (ret) {
689 		vfio_iommu_group_put(group, dev);
690 		return ret;
691 	}
692 
693 	mutex_init(&vdev->igate);
694 
695 	return 0;
696 }
697 EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
698 
699 struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
700 {
701 	struct vfio_platform_device *vdev;
702 
703 	vdev = vfio_del_group_dev(dev);
704 
705 	if (vdev) {
706 		vfio_platform_put_reset(vdev);
707 		vfio_iommu_group_put(dev->iommu_group, dev);
708 	}
709 
710 	return vdev;
711 }
712 EXPORT_SYMBOL_GPL(vfio_platform_remove_common);
713 
714 void __vfio_platform_register_reset(struct vfio_platform_reset_node *node)
715 {
716 	mutex_lock(&driver_lock);
717 	list_add(&node->link, &reset_list);
718 	mutex_unlock(&driver_lock);
719 }
720 EXPORT_SYMBOL_GPL(__vfio_platform_register_reset);
721 
722 void vfio_platform_unregister_reset(const char *compat,
723 				    vfio_platform_reset_fn_t fn)
724 {
725 	struct vfio_platform_reset_node *iter, *temp;
726 
727 	mutex_lock(&driver_lock);
728 	list_for_each_entry_safe(iter, temp, &reset_list, link) {
729 		if (!strcmp(iter->compat, compat) && (iter->of_reset == fn)) {
730 			list_del(&iter->link);
731 			break;
732 		}
733 	}
734 
735 	mutex_unlock(&driver_lock);
736 
737 }
738 EXPORT_SYMBOL_GPL(vfio_platform_unregister_reset);
739 
740 MODULE_VERSION(DRIVER_VERSION);
741 MODULE_LICENSE("GPL v2");
742 MODULE_AUTHOR(DRIVER_AUTHOR);
743 MODULE_DESCRIPTION(DRIVER_DESC);
744