xref: /linux-6.15/include/linux/iommu.h (revision bbb03029)
1 /*
2  * Copyright (C) 2007-2008 Advanced Micro Devices, Inc.
3  * Author: Joerg Roedel <[email protected]>
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms of the GNU General Public License version 2 as published
7  * 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  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
17  */
18 
19 #ifndef __LINUX_IOMMU_H
20 #define __LINUX_IOMMU_H
21 
22 #include <linux/scatterlist.h>
23 #include <linux/device.h>
24 #include <linux/types.h>
25 #include <linux/errno.h>
26 #include <linux/err.h>
27 #include <linux/of.h>
28 
29 #define IOMMU_READ	(1 << 0)
30 #define IOMMU_WRITE	(1 << 1)
31 #define IOMMU_CACHE	(1 << 2) /* DMA cache coherency */
32 #define IOMMU_NOEXEC	(1 << 3)
33 #define IOMMU_MMIO	(1 << 4) /* e.g. things like MSI doorbells */
34 /*
35  * Where the bus hardware includes a privilege level as part of its access type
36  * markings, and certain devices are capable of issuing transactions marked as
37  * either 'supervisor' or 'user', the IOMMU_PRIV flag requests that the other
38  * given permission flags only apply to accesses at the higher privilege level,
39  * and that unprivileged transactions should have as little access as possible.
40  * This would usually imply the same permissions as kernel mappings on the CPU,
41  * if the IOMMU page table format is equivalent.
42  */
43 #define IOMMU_PRIV	(1 << 5)
44 
45 struct iommu_ops;
46 struct iommu_group;
47 struct bus_type;
48 struct device;
49 struct iommu_domain;
50 struct notifier_block;
51 
52 /* iommu fault flags */
53 #define IOMMU_FAULT_READ	0x0
54 #define IOMMU_FAULT_WRITE	0x1
55 
56 typedef int (*iommu_fault_handler_t)(struct iommu_domain *,
57 			struct device *, unsigned long, int, void *);
58 
59 struct iommu_domain_geometry {
60 	dma_addr_t aperture_start; /* First address that can be mapped    */
61 	dma_addr_t aperture_end;   /* Last address that can be mapped     */
62 	bool force_aperture;       /* DMA only allowed in mappable range? */
63 };
64 
65 /* Domain feature flags */
66 #define __IOMMU_DOMAIN_PAGING	(1U << 0)  /* Support for iommu_map/unmap */
67 #define __IOMMU_DOMAIN_DMA_API	(1U << 1)  /* Domain for use in DMA-API
68 					      implementation              */
69 #define __IOMMU_DOMAIN_PT	(1U << 2)  /* Domain is identity mapped   */
70 
71 /*
72  * This are the possible domain-types
73  *
74  *	IOMMU_DOMAIN_BLOCKED	- All DMA is blocked, can be used to isolate
75  *				  devices
76  *	IOMMU_DOMAIN_IDENTITY	- DMA addresses are system physical addresses
77  *	IOMMU_DOMAIN_UNMANAGED	- DMA mappings managed by IOMMU-API user, used
78  *				  for VMs
79  *	IOMMU_DOMAIN_DMA	- Internally used for DMA-API implementations.
80  *				  This flag allows IOMMU drivers to implement
81  *				  certain optimizations for these domains
82  */
83 #define IOMMU_DOMAIN_BLOCKED	(0U)
84 #define IOMMU_DOMAIN_IDENTITY	(__IOMMU_DOMAIN_PT)
85 #define IOMMU_DOMAIN_UNMANAGED	(__IOMMU_DOMAIN_PAGING)
86 #define IOMMU_DOMAIN_DMA	(__IOMMU_DOMAIN_PAGING |	\
87 				 __IOMMU_DOMAIN_DMA_API)
88 
89 struct iommu_domain {
90 	unsigned type;
91 	const struct iommu_ops *ops;
92 	unsigned long pgsize_bitmap;	/* Bitmap of page sizes in use */
93 	iommu_fault_handler_t handler;
94 	void *handler_token;
95 	struct iommu_domain_geometry geometry;
96 	void *iova_cookie;
97 };
98 
99 enum iommu_cap {
100 	IOMMU_CAP_CACHE_COHERENCY,	/* IOMMU can enforce cache coherent DMA
101 					   transactions */
102 	IOMMU_CAP_INTR_REMAP,		/* IOMMU supports interrupt isolation */
103 	IOMMU_CAP_NOEXEC,		/* IOMMU_NOEXEC flag */
104 };
105 
106 /*
107  * Following constraints are specifc to FSL_PAMUV1:
108  *  -aperture must be power of 2, and naturally aligned
109  *  -number of windows must be power of 2, and address space size
110  *   of each window is determined by aperture size / # of windows
111  *  -the actual size of the mapped region of a window must be power
112  *   of 2 starting with 4KB and physical address must be naturally
113  *   aligned.
114  * DOMAIN_ATTR_FSL_PAMUV1 corresponds to the above mentioned contraints.
115  * The caller can invoke iommu_domain_get_attr to check if the underlying
116  * iommu implementation supports these constraints.
117  */
118 
119 enum iommu_attr {
120 	DOMAIN_ATTR_GEOMETRY,
121 	DOMAIN_ATTR_PAGING,
122 	DOMAIN_ATTR_WINDOWS,
123 	DOMAIN_ATTR_FSL_PAMU_STASH,
124 	DOMAIN_ATTR_FSL_PAMU_ENABLE,
125 	DOMAIN_ATTR_FSL_PAMUV1,
126 	DOMAIN_ATTR_NESTING,	/* two stages of translation */
127 	DOMAIN_ATTR_MAX,
128 };
129 
130 /* These are the possible reserved region types */
131 enum iommu_resv_type {
132 	/* Memory regions which must be mapped 1:1 at all times */
133 	IOMMU_RESV_DIRECT,
134 	/* Arbitrary "never map this or give it to a device" address ranges */
135 	IOMMU_RESV_RESERVED,
136 	/* Hardware MSI region (untranslated) */
137 	IOMMU_RESV_MSI,
138 	/* Software-managed MSI translation window */
139 	IOMMU_RESV_SW_MSI,
140 };
141 
142 /**
143  * struct iommu_resv_region - descriptor for a reserved memory region
144  * @list: Linked list pointers
145  * @start: System physical start address of the region
146  * @length: Length of the region in bytes
147  * @prot: IOMMU Protection flags (READ/WRITE/...)
148  * @type: Type of the reserved region
149  */
150 struct iommu_resv_region {
151 	struct list_head	list;
152 	phys_addr_t		start;
153 	size_t			length;
154 	int			prot;
155 	enum iommu_resv_type	type;
156 };
157 
158 #ifdef CONFIG_IOMMU_API
159 
160 /**
161  * struct iommu_ops - iommu ops and capabilities
162  * @capable: check capability
163  * @domain_alloc: allocate iommu domain
164  * @domain_free: free iommu domain
165  * @attach_dev: attach device to an iommu domain
166  * @detach_dev: detach device from an iommu domain
167  * @map: map a physically contiguous memory region to an iommu domain
168  * @unmap: unmap a physically contiguous memory region from an iommu domain
169  * @map_sg: map a scatter-gather list of physically contiguous memory chunks
170  * to an iommu domain
171  * @iova_to_phys: translate iova to physical address
172  * @add_device: add device to iommu grouping
173  * @remove_device: remove device from iommu grouping
174  * @device_group: find iommu group for a particular device
175  * @domain_get_attr: Query domain attributes
176  * @domain_set_attr: Change domain attributes
177  * @get_resv_regions: Request list of reserved regions for a device
178  * @put_resv_regions: Free list of reserved regions for a device
179  * @apply_resv_region: Temporary helper call-back for iova reserved ranges
180  * @domain_window_enable: Configure and enable a particular window for a domain
181  * @domain_window_disable: Disable a particular window for a domain
182  * @domain_set_windows: Set the number of windows for a domain
183  * @domain_get_windows: Return the number of windows for a domain
184  * @of_xlate: add OF master IDs to iommu grouping
185  * @pgsize_bitmap: bitmap of all possible supported page sizes
186  */
187 struct iommu_ops {
188 	bool (*capable)(enum iommu_cap);
189 
190 	/* Domain allocation and freeing by the iommu driver */
191 	struct iommu_domain *(*domain_alloc)(unsigned iommu_domain_type);
192 	void (*domain_free)(struct iommu_domain *);
193 
194 	int (*attach_dev)(struct iommu_domain *domain, struct device *dev);
195 	void (*detach_dev)(struct iommu_domain *domain, struct device *dev);
196 	int (*map)(struct iommu_domain *domain, unsigned long iova,
197 		   phys_addr_t paddr, size_t size, int prot);
198 	size_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
199 		     size_t size);
200 	size_t (*map_sg)(struct iommu_domain *domain, unsigned long iova,
201 			 struct scatterlist *sg, unsigned int nents, int prot);
202 	phys_addr_t (*iova_to_phys)(struct iommu_domain *domain, dma_addr_t iova);
203 	int (*add_device)(struct device *dev);
204 	void (*remove_device)(struct device *dev);
205 	struct iommu_group *(*device_group)(struct device *dev);
206 	int (*domain_get_attr)(struct iommu_domain *domain,
207 			       enum iommu_attr attr, void *data);
208 	int (*domain_set_attr)(struct iommu_domain *domain,
209 			       enum iommu_attr attr, void *data);
210 
211 	/* Request/Free a list of reserved regions for a device */
212 	void (*get_resv_regions)(struct device *dev, struct list_head *list);
213 	void (*put_resv_regions)(struct device *dev, struct list_head *list);
214 	void (*apply_resv_region)(struct device *dev,
215 				  struct iommu_domain *domain,
216 				  struct iommu_resv_region *region);
217 
218 	/* Window handling functions */
219 	int (*domain_window_enable)(struct iommu_domain *domain, u32 wnd_nr,
220 				    phys_addr_t paddr, u64 size, int prot);
221 	void (*domain_window_disable)(struct iommu_domain *domain, u32 wnd_nr);
222 	/* Set the number of windows per domain */
223 	int (*domain_set_windows)(struct iommu_domain *domain, u32 w_count);
224 	/* Get the number of windows per domain */
225 	u32 (*domain_get_windows)(struct iommu_domain *domain);
226 
227 	int (*of_xlate)(struct device *dev, struct of_phandle_args *args);
228 
229 	unsigned long pgsize_bitmap;
230 };
231 
232 /**
233  * struct iommu_device - IOMMU core representation of one IOMMU hardware
234  *			 instance
235  * @list: Used by the iommu-core to keep a list of registered iommus
236  * @ops: iommu-ops for talking to this iommu
237  * @dev: struct device for sysfs handling
238  */
239 struct iommu_device {
240 	struct list_head list;
241 	const struct iommu_ops *ops;
242 	struct fwnode_handle *fwnode;
243 	struct device dev;
244 };
245 
246 int  iommu_device_register(struct iommu_device *iommu);
247 void iommu_device_unregister(struct iommu_device *iommu);
248 int  iommu_device_sysfs_add(struct iommu_device *iommu,
249 			    struct device *parent,
250 			    const struct attribute_group **groups,
251 			    const char *fmt, ...) __printf(4, 5);
252 void iommu_device_sysfs_remove(struct iommu_device *iommu);
253 int  iommu_device_link(struct iommu_device   *iommu, struct device *link);
254 void iommu_device_unlink(struct iommu_device *iommu, struct device *link);
255 
256 static inline void iommu_device_set_ops(struct iommu_device *iommu,
257 					const struct iommu_ops *ops)
258 {
259 	iommu->ops = ops;
260 }
261 
262 static inline void iommu_device_set_fwnode(struct iommu_device *iommu,
263 					   struct fwnode_handle *fwnode)
264 {
265 	iommu->fwnode = fwnode;
266 }
267 
268 #define IOMMU_GROUP_NOTIFY_ADD_DEVICE		1 /* Device added */
269 #define IOMMU_GROUP_NOTIFY_DEL_DEVICE		2 /* Pre Device removed */
270 #define IOMMU_GROUP_NOTIFY_BIND_DRIVER		3 /* Pre Driver bind */
271 #define IOMMU_GROUP_NOTIFY_BOUND_DRIVER		4 /* Post Driver bind */
272 #define IOMMU_GROUP_NOTIFY_UNBIND_DRIVER	5 /* Pre Driver unbind */
273 #define IOMMU_GROUP_NOTIFY_UNBOUND_DRIVER	6 /* Post Driver unbind */
274 
275 extern int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops);
276 extern bool iommu_present(struct bus_type *bus);
277 extern bool iommu_capable(struct bus_type *bus, enum iommu_cap cap);
278 extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
279 extern struct iommu_group *iommu_group_get_by_id(int id);
280 extern void iommu_domain_free(struct iommu_domain *domain);
281 extern int iommu_attach_device(struct iommu_domain *domain,
282 			       struct device *dev);
283 extern void iommu_detach_device(struct iommu_domain *domain,
284 				struct device *dev);
285 extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
286 extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
287 		     phys_addr_t paddr, size_t size, int prot);
288 extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
289 		       size_t size);
290 extern size_t default_iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
291 				struct scatterlist *sg,unsigned int nents,
292 				int prot);
293 extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova);
294 extern void iommu_set_fault_handler(struct iommu_domain *domain,
295 			iommu_fault_handler_t handler, void *token);
296 
297 extern void iommu_get_resv_regions(struct device *dev, struct list_head *list);
298 extern void iommu_put_resv_regions(struct device *dev, struct list_head *list);
299 extern int iommu_request_dm_for_dev(struct device *dev);
300 extern struct iommu_resv_region *
301 iommu_alloc_resv_region(phys_addr_t start, size_t length, int prot,
302 			enum iommu_resv_type type);
303 extern int iommu_get_group_resv_regions(struct iommu_group *group,
304 					struct list_head *head);
305 
306 extern int iommu_attach_group(struct iommu_domain *domain,
307 			      struct iommu_group *group);
308 extern void iommu_detach_group(struct iommu_domain *domain,
309 			       struct iommu_group *group);
310 extern struct iommu_group *iommu_group_alloc(void);
311 extern void *iommu_group_get_iommudata(struct iommu_group *group);
312 extern void iommu_group_set_iommudata(struct iommu_group *group,
313 				      void *iommu_data,
314 				      void (*release)(void *iommu_data));
315 extern int iommu_group_set_name(struct iommu_group *group, const char *name);
316 extern int iommu_group_add_device(struct iommu_group *group,
317 				  struct device *dev);
318 extern void iommu_group_remove_device(struct device *dev);
319 extern int iommu_group_for_each_dev(struct iommu_group *group, void *data,
320 				    int (*fn)(struct device *, void *));
321 extern struct iommu_group *iommu_group_get(struct device *dev);
322 extern struct iommu_group *iommu_group_ref_get(struct iommu_group *group);
323 extern void iommu_group_put(struct iommu_group *group);
324 extern int iommu_group_register_notifier(struct iommu_group *group,
325 					 struct notifier_block *nb);
326 extern int iommu_group_unregister_notifier(struct iommu_group *group,
327 					   struct notifier_block *nb);
328 extern int iommu_group_id(struct iommu_group *group);
329 extern struct iommu_group *iommu_group_get_for_dev(struct device *dev);
330 extern struct iommu_domain *iommu_group_default_domain(struct iommu_group *);
331 
332 extern int iommu_domain_get_attr(struct iommu_domain *domain, enum iommu_attr,
333 				 void *data);
334 extern int iommu_domain_set_attr(struct iommu_domain *domain, enum iommu_attr,
335 				 void *data);
336 
337 /* Window handling function prototypes */
338 extern int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr,
339 				      phys_addr_t offset, u64 size,
340 				      int prot);
341 extern void iommu_domain_window_disable(struct iommu_domain *domain, u32 wnd_nr);
342 
343 extern int report_iommu_fault(struct iommu_domain *domain, struct device *dev,
344 			      unsigned long iova, int flags);
345 
346 static inline size_t iommu_map_sg(struct iommu_domain *domain,
347 				  unsigned long iova, struct scatterlist *sg,
348 				  unsigned int nents, int prot)
349 {
350 	return domain->ops->map_sg(domain, iova, sg, nents, prot);
351 }
352 
353 /* PCI device grouping function */
354 extern struct iommu_group *pci_device_group(struct device *dev);
355 /* Generic device grouping function */
356 extern struct iommu_group *generic_device_group(struct device *dev);
357 
358 /**
359  * struct iommu_fwspec - per-device IOMMU instance data
360  * @ops: ops for this device's IOMMU
361  * @iommu_fwnode: firmware handle for this device's IOMMU
362  * @iommu_priv: IOMMU driver private data for this device
363  * @num_ids: number of associated device IDs
364  * @ids: IDs which this device may present to the IOMMU
365  */
366 struct iommu_fwspec {
367 	const struct iommu_ops	*ops;
368 	struct fwnode_handle	*iommu_fwnode;
369 	void			*iommu_priv;
370 	unsigned int		num_ids;
371 	u32			ids[1];
372 };
373 
374 int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
375 		      const struct iommu_ops *ops);
376 void iommu_fwspec_free(struct device *dev);
377 int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids);
378 const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode);
379 
380 #else /* CONFIG_IOMMU_API */
381 
382 struct iommu_ops {};
383 struct iommu_group {};
384 struct iommu_fwspec {};
385 struct iommu_device {};
386 
387 static inline bool iommu_present(struct bus_type *bus)
388 {
389 	return false;
390 }
391 
392 static inline bool iommu_capable(struct bus_type *bus, enum iommu_cap cap)
393 {
394 	return false;
395 }
396 
397 static inline struct iommu_domain *iommu_domain_alloc(struct bus_type *bus)
398 {
399 	return NULL;
400 }
401 
402 static inline struct iommu_group *iommu_group_get_by_id(int id)
403 {
404 	return NULL;
405 }
406 
407 static inline void iommu_domain_free(struct iommu_domain *domain)
408 {
409 }
410 
411 static inline int iommu_attach_device(struct iommu_domain *domain,
412 				      struct device *dev)
413 {
414 	return -ENODEV;
415 }
416 
417 static inline void iommu_detach_device(struct iommu_domain *domain,
418 				       struct device *dev)
419 {
420 }
421 
422 static inline struct iommu_domain *iommu_get_domain_for_dev(struct device *dev)
423 {
424 	return NULL;
425 }
426 
427 static inline int iommu_map(struct iommu_domain *domain, unsigned long iova,
428 			    phys_addr_t paddr, int gfp_order, int prot)
429 {
430 	return -ENODEV;
431 }
432 
433 static inline int iommu_unmap(struct iommu_domain *domain, unsigned long iova,
434 			      int gfp_order)
435 {
436 	return -ENODEV;
437 }
438 
439 static inline size_t iommu_map_sg(struct iommu_domain *domain,
440 				  unsigned long iova, struct scatterlist *sg,
441 				  unsigned int nents, int prot)
442 {
443 	return -ENODEV;
444 }
445 
446 static inline int iommu_domain_window_enable(struct iommu_domain *domain,
447 					     u32 wnd_nr, phys_addr_t paddr,
448 					     u64 size, int prot)
449 {
450 	return -ENODEV;
451 }
452 
453 static inline void iommu_domain_window_disable(struct iommu_domain *domain,
454 					       u32 wnd_nr)
455 {
456 }
457 
458 static inline phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
459 {
460 	return 0;
461 }
462 
463 static inline void iommu_set_fault_handler(struct iommu_domain *domain,
464 				iommu_fault_handler_t handler, void *token)
465 {
466 }
467 
468 static inline void iommu_get_resv_regions(struct device *dev,
469 					struct list_head *list)
470 {
471 }
472 
473 static inline void iommu_put_resv_regions(struct device *dev,
474 					struct list_head *list)
475 {
476 }
477 
478 static inline int iommu_get_group_resv_regions(struct iommu_group *group,
479 					       struct list_head *head)
480 {
481 	return -ENODEV;
482 }
483 
484 static inline int iommu_request_dm_for_dev(struct device *dev)
485 {
486 	return -ENODEV;
487 }
488 
489 static inline int iommu_attach_group(struct iommu_domain *domain,
490 				     struct iommu_group *group)
491 {
492 	return -ENODEV;
493 }
494 
495 static inline void iommu_detach_group(struct iommu_domain *domain,
496 				      struct iommu_group *group)
497 {
498 }
499 
500 static inline struct iommu_group *iommu_group_alloc(void)
501 {
502 	return ERR_PTR(-ENODEV);
503 }
504 
505 static inline void *iommu_group_get_iommudata(struct iommu_group *group)
506 {
507 	return NULL;
508 }
509 
510 static inline void iommu_group_set_iommudata(struct iommu_group *group,
511 					     void *iommu_data,
512 					     void (*release)(void *iommu_data))
513 {
514 }
515 
516 static inline int iommu_group_set_name(struct iommu_group *group,
517 				       const char *name)
518 {
519 	return -ENODEV;
520 }
521 
522 static inline int iommu_group_add_device(struct iommu_group *group,
523 					 struct device *dev)
524 {
525 	return -ENODEV;
526 }
527 
528 static inline void iommu_group_remove_device(struct device *dev)
529 {
530 }
531 
532 static inline int iommu_group_for_each_dev(struct iommu_group *group,
533 					   void *data,
534 					   int (*fn)(struct device *, void *))
535 {
536 	return -ENODEV;
537 }
538 
539 static inline struct iommu_group *iommu_group_get(struct device *dev)
540 {
541 	return NULL;
542 }
543 
544 static inline void iommu_group_put(struct iommu_group *group)
545 {
546 }
547 
548 static inline int iommu_group_register_notifier(struct iommu_group *group,
549 						struct notifier_block *nb)
550 {
551 	return -ENODEV;
552 }
553 
554 static inline int iommu_group_unregister_notifier(struct iommu_group *group,
555 						  struct notifier_block *nb)
556 {
557 	return 0;
558 }
559 
560 static inline int iommu_group_id(struct iommu_group *group)
561 {
562 	return -ENODEV;
563 }
564 
565 static inline int iommu_domain_get_attr(struct iommu_domain *domain,
566 					enum iommu_attr attr, void *data)
567 {
568 	return -EINVAL;
569 }
570 
571 static inline int iommu_domain_set_attr(struct iommu_domain *domain,
572 					enum iommu_attr attr, void *data)
573 {
574 	return -EINVAL;
575 }
576 
577 static inline int  iommu_device_register(struct iommu_device *iommu)
578 {
579 	return -ENODEV;
580 }
581 
582 static inline void iommu_device_set_ops(struct iommu_device *iommu,
583 					const struct iommu_ops *ops)
584 {
585 }
586 
587 static inline void iommu_device_set_fwnode(struct iommu_device *iommu,
588 					   struct fwnode_handle *fwnode)
589 {
590 }
591 
592 static inline void iommu_device_unregister(struct iommu_device *iommu)
593 {
594 }
595 
596 static inline int  iommu_device_sysfs_add(struct iommu_device *iommu,
597 					  struct device *parent,
598 					  const struct attribute_group **groups,
599 					  const char *fmt, ...)
600 {
601 	return -ENODEV;
602 }
603 
604 static inline void iommu_device_sysfs_remove(struct iommu_device *iommu)
605 {
606 }
607 
608 static inline int iommu_device_link(struct device *dev, struct device *link)
609 {
610 	return -EINVAL;
611 }
612 
613 static inline void iommu_device_unlink(struct device *dev, struct device *link)
614 {
615 }
616 
617 static inline int iommu_fwspec_init(struct device *dev,
618 				    struct fwnode_handle *iommu_fwnode,
619 				    const struct iommu_ops *ops)
620 {
621 	return -ENODEV;
622 }
623 
624 static inline void iommu_fwspec_free(struct device *dev)
625 {
626 }
627 
628 static inline int iommu_fwspec_add_ids(struct device *dev, u32 *ids,
629 				       int num_ids)
630 {
631 	return -ENODEV;
632 }
633 
634 static inline
635 const struct iommu_ops *iommu_ops_from_fwnode(struct fwnode_handle *fwnode)
636 {
637 	return NULL;
638 }
639 
640 #endif /* CONFIG_IOMMU_API */
641 
642 #endif /* __LINUX_IOMMU_H */
643