include/linux/iommu.h

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