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_dm_region - descriptor for a direct mapped 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_dm_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_dm_regions: Request list of direct mapping requirements for a device
 154  * @put_dm_regions: Free list of direct mapping requirements for a device
 155  * @apply_dm_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 direct mapping requirements for a device */
 188         void (*get_dm_regions)(struct device *dev, struct list_head *list);
 189         void (*put_dm_regions)(struct device *dev, struct list_head *list);
 190         void (*apply_dm_region)(struct device *dev, struct iommu_domain *domain,
 191                                 struct iommu_dm_region *region);
 192
 193         /* Window handling functions */
 194         int (*domain_window_enable)(struct iommu_domain *domain, u32 wnd_nr,
 195                                     phys_addr_t paddr, u64 size, int prot);
 196         void (*domain_window_disable)(struct iommu_domain *domain, u32 wnd_nr);
 197         /* Set the number of windows per domain */
 198         int (*domain_set_windows)(struct iommu_domain *domain, u32 w_count);
 199         /* Get the number of windows per domain */
 200         u32 (*domain_get_windows)(struct iommu_domain *domain);
 201
 202         int (*of_xlate)(struct device *dev, struct of_phandle_args *args);
 203
 204         unsigned long pgsize_bitmap;
 205 };
 206
 207 #define IOMMU_GROUP_NOTIFY_ADD_DEVICE           1 /* Device added */
 208 #define IOMMU_GROUP_NOTIFY_DEL_DEVICE           2 /* Pre Device removed */
 209 #define IOMMU_GROUP_NOTIFY_BIND_DRIVER          3 /* Pre Driver bind */
 210 #define IOMMU_GROUP_NOTIFY_BOUND_DRIVER         4 /* Post Driver bind */
 211 #define IOMMU_GROUP_NOTIFY_UNBIND_DRIVER        5 /* Pre Driver unbind */
 212 #define IOMMU_GROUP_NOTIFY_UNBOUND_DRIVER       6 /* Post Driver unbind */
 213
 214 extern int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops);
 215 extern bool iommu_present(struct bus_type *bus);
 216 extern bool iommu_capable(struct bus_type *bus, enum iommu_cap cap);
 217 extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
 218 extern struct iommu_group *iommu_group_get_by_id(int id);
 219 extern void iommu_domain_free(struct iommu_domain *domain);
 220 extern int iommu_attach_device(struct iommu_domain *domain,
 221                                struct device *dev);
 222 extern void iommu_detach_device(struct iommu_domain *domain,
 223                                 struct device *dev);
 224 extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
 225 extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
 226                      phys_addr_t paddr, size_t size, int prot);
 227 extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova,
 228                        size_t size);
 229 extern size_t default_iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
 230                                 struct scatterlist *sg,unsigned int nents,
 231                                 int prot);
 232 extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova);
 233 extern void iommu_set_fault_handler(struct iommu_domain *domain,
 234                         iommu_fault_handler_t handler, void *token);
 235
 236 extern void iommu_get_dm_regions(struct device *dev, struct list_head *list);
 237 extern void iommu_put_dm_regions(struct device *dev, struct list_head *list);
 238 extern int iommu_request_dm_for_dev(struct device *dev);
 239
 240 extern int iommu_attach_group(struct iommu_domain *domain,
 241                               struct iommu_group *group);
 242 extern void iommu_detach_group(struct iommu_domain *domain,
 243                                struct iommu_group *group);
 244 extern struct iommu_group *iommu_group_alloc(void);
 245 extern void *iommu_group_get_iommudata(struct iommu_group *group);
 246 extern void iommu_group_set_iommudata(struct iommu_group *group,
 247                                       void *iommu_data,
 248                                       void (*release)(void *iommu_data));
 249 extern int iommu_group_set_name(struct iommu_group *group, const char *name);
 250 extern int iommu_group_add_device(struct iommu_group *group,
 251                                   struct device *dev);
 252 extern void iommu_group_remove_device(struct device *dev);
 253 extern int iommu_group_for_each_dev(struct iommu_group *group, void *data,
 254                                     int (*fn)(struct device *, void *));
 255 extern struct iommu_group *iommu_group_get(struct device *dev);
 256 extern struct iommu_group *iommu_group_ref_get(struct iommu_group *group);
 257 extern void iommu_group_put(struct iommu_group *group);
 258 extern int iommu_group_register_notifier(struct iommu_group *group,
 259                                          struct notifier_block *nb);
 260 extern int iommu_group_unregister_notifier(struct iommu_group *group,
 261                                            struct notifier_block *nb);
 262 extern int iommu_group_id(struct iommu_group *group);
 263 extern struct iommu_group *iommu_group_get_for_dev(struct device *dev);
 264 extern struct iommu_domain *iommu_group_default_domain(struct iommu_group *);
 265
 266 extern int iommu_domain_get_attr(struct iommu_domain *domain, enum iommu_attr,
 267                                  void *data);
 268 extern int iommu_domain_set_attr(struct iommu_domain *domain, enum iommu_attr,
 269                                  void *data);
 270 struct device *iommu_device_create(struct device *parent, void *drvdata,
 271                                    const struct attribute_group **groups,
 272                                    const char *fmt, ...) __printf(4, 5);
 273 void iommu_device_destroy(struct device *dev);
 274 int iommu_device_link(struct device *dev, struct device *link);
 275 void iommu_device_unlink(struct device *dev, struct device *link);
 276
 277 /* Window handling function prototypes */
 278 extern int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr,
 279                                       phys_addr_t offset, u64 size,
 280                                       int prot);
 281 extern void iommu_domain_window_disable(struct iommu_domain *domain, u32 wnd_nr);
 282 /**
 283  * report_iommu_fault() - report about an IOMMU fault to the IOMMU framework
 284  * @domain: the iommu domain where the fault has happened
 285  * @dev: the device where the fault has happened
 286  * @iova: the faulting address
 287  * @flags: mmu fault flags (e.g. IOMMU_FAULT_READ/IOMMU_FAULT_WRITE/...)
 288  *
 289  * This function should be called by the low-level IOMMU implementations
 290  * whenever IOMMU faults happen, to allow high-level users, that are
 291  * interested in such events, to know about them.
 292  *
 293  * This event may be useful for several possible use cases:
 294  * - mere logging of the event
 295  * - dynamic TLB/PTE loading
 296  * - if restarting of the faulting device is required
 297  *
 298  * Returns 0 on success and an appropriate error code otherwise (if dynamic
 299  * PTE/TLB loading will one day be supported, implementations will be able
 300  * to tell whether it succeeded or not according to this return value).
 301  *
 302  * Specifically, -ENOSYS is returned if a fault handler isn't installed
 303  * (though fault handlers can also return -ENOSYS, in case they want to
 304  * elicit the default behavior of the IOMMU drivers).
 305  */
 306 static inline int report_iommu_fault(struct iommu_domain *domain,
 307                 struct device *dev, unsigned long iova, int flags)
 308 {
 309         int ret = -ENOSYS;
 310
 311         /*
 312          * if upper layers showed interest and installed a fault handler,
 313          * invoke it.
 314          */
 315         if (domain->handler)
 316                 ret = domain->handler(domain, dev, iova, flags,
 317                                                 domain->handler_token);
 318
 319         trace_io_page_fault(dev, iova, flags);
 320         return ret;
 321 }
 322
 323 static inline size_t iommu_map_sg(struct iommu_domain *domain,
 324                                   unsigned long iova, struct scatterlist *sg,
 325                                   unsigned int nents, int prot)
 326 {
 327         return domain->ops->map_sg(domain, iova, sg, nents, prot);
 328 }
 329
 330 /* PCI device grouping function */
 331 extern struct iommu_group *pci_device_group(struct device *dev);
 332 /* Generic device grouping function */
 333 extern struct iommu_group *generic_device_group(struct device *dev);
 334
 335 /**
 336  * struct iommu_fwspec - per-device IOMMU instance data
 337  * @ops: ops for this device's IOMMU
 338  * @iommu_fwnode: firmware handle for this device's IOMMU
 339  * @iommu_priv: IOMMU driver private data for this device
 340  * @num_ids: number of associated device IDs
 341  * @ids: IDs which this device may present to the IOMMU
 342  */
 343 struct iommu_fwspec {
 344         const struct iommu_ops  *ops;
 345         struct fwnode_handle    *iommu_fwnode;
 346         void                    *iommu_priv;
 347         unsigned int            num_ids;
 348         u32                     ids[1];
 349 };
 350
 351 int iommu_fwspec_init(struct device *dev, struct fwnode_handle *iommu_fwnode,
 352                       const struct iommu_ops *ops);
 353 void iommu_fwspec_free(struct device *dev);
 354 int iommu_fwspec_add_ids(struct device *dev, u32 *ids, int num_ids);
 355 void iommu_register_instance(struct fwnode_handle *fwnode,
 356                              const struct iommu_ops *ops);
 357 const struct iommu_ops *iommu_get_instance(struct fwnode_handle *fwnode);
 358
 359 #else /* CONFIG_IOMMU_API */
 360
 361 struct iommu_ops {};
 362 struct iommu_group {};
 363 struct iommu_fwspec {};
 364
 365 static inline bool iommu_present(struct bus_type *bus)
 366 {
 367         return false;
 368 }
 369
 370 static inline bool iommu_capable(struct bus_type *bus, enum iommu_cap cap)
 371 {
 372         return false;
 373 }
 374
 375 static inline struct iommu_domain *iommu_domain_alloc(struct bus_type *bus)
 376 {
 377         return NULL;
 378 }
 379
 380 static inline struct iommu_group *iommu_group_get_by_id(int id)
 381 {
 382         return NULL;
 383 }
 384
 385 static inline void iommu_domain_free(struct iommu_domain *domain)
 386 {
 387 }
 388
 389 static inline int iommu_attach_device(struct iommu_domain *domain,
 390                                       struct device *dev)
 391 {
 392         return -ENODEV;
 393 }
 394
 395 static inline void iommu_detach_device(struct iommu_domain *domain,
 396                                        struct device *dev)
 397 {
 398 }
 399
 400 static inline struct iommu_domain *iommu_get_domain_for_dev(struct device *dev)
 401 {
 402         return NULL;
 403 }
 404
 405 static inline int iommu_map(struct iommu_domain *domain, unsigned long iova,
 406                             phys_addr_t paddr, int gfp_order, int prot)
 407 {
 408         return -ENODEV;
 409 }
 410
 411 static inline int iommu_unmap(struct iommu_domain *domain, unsigned long iova,
 412                               int gfp_order)
 413 {
 414         return -ENODEV;
 415 }
 416
 417 static inline size_t iommu_map_sg(struct iommu_domain *domain,
 418                                   unsigned long iova, struct scatterlist *sg,
 419                                   unsigned int nents, int prot)
 420 {
 421         return -ENODEV;
 422 }
 423
 424 static inline int iommu_domain_window_enable(struct iommu_domain *domain,
 425                                              u32 wnd_nr, phys_addr_t paddr,
 426                                              u64 size, int prot)
 427 {
 428         return -ENODEV;
 429 }
 430
 431 static inline void iommu_domain_window_disable(struct iommu_domain *domain,
 432                                                u32 wnd_nr)
 433 {
 434 }
 435
 436 static inline phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
 437 {
 438         return 0;
 439 }
 440
 441 static inline void iommu_set_fault_handler(struct iommu_domain *domain,
 442                                 iommu_fault_handler_t handler, void *token)
 443 {
 444 }
 445
 446 static inline void iommu_get_dm_regions(struct device *dev,
 447                                         struct list_head *list)
 448 {
 449 }
 450
 451 static inline void iommu_put_dm_regions(struct device *dev,
 452                                         struct list_head *list)
 453 {
 454 }
 455
 456 static inline int iommu_request_dm_for_dev(struct device *dev)
 457 {
 458         return -ENODEV;
 459 }
 460
 461 static inline int iommu_attach_group(struct iommu_domain *domain,
 462                                      struct iommu_group *group)
 463 {
 464         return -ENODEV;
 465 }
 466
 467 static inline void iommu_detach_group(struct iommu_domain *domain,
 468                                       struct iommu_group *group)
 469 {
 470 }
 471
 472 static inline struct iommu_group *iommu_group_alloc(void)
 473 {
 474         return ERR_PTR(-ENODEV);
 475 }
 476
 477 static inline void *iommu_group_get_iommudata(struct iommu_group *group)
 478 {
 479         return NULL;
 480 }
 481
 482 static inline void iommu_group_set_iommudata(struct iommu_group *group,
 483                                              void *iommu_data,
 484                                              void (*release)(void *iommu_data))
 485 {
 486 }
 487
 488 static inline int iommu_group_set_name(struct iommu_group *group,
 489                                        const char *name)
 490 {
 491         return -ENODEV;
 492 }
 493
 494 static inline int iommu_group_add_device(struct iommu_group *group,
 495                                          struct device *dev)
 496 {
 497         return -ENODEV;
 498 }
 499
 500 static inline void iommu_group_remove_device(struct device *dev)
 501 {
 502 }
 503
 504 static inline int iommu_group_for_each_dev(struct iommu_group *group,
 505                                            void *data,
 506                                            int (*fn)(struct device *, void *))
 507 {
 508         return -ENODEV;
 509 }
 510
 511 static inline struct iommu_group *iommu_group_get(struct device *dev)
 512 {
 513         return NULL;
 514 }
 515
 516 static inline void iommu_group_put(struct iommu_group *group)
 517 {
 518 }
 519
 520 static inline int iommu_group_register_notifier(struct iommu_group *group,
 521                                                 struct notifier_block *nb)
 522 {
 523         return -ENODEV;
 524 }
 525
 526 static inline int iommu_group_unregister_notifier(struct iommu_group *group,
 527                                                   struct notifier_block *nb)
 528 {
 529         return 0;
 530 }
 531
 532 static inline int iommu_group_id(struct iommu_group *group)
 533 {
 534         return -ENODEV;
 535 }
 536
 537 static inline int iommu_domain_get_attr(struct iommu_domain *domain,
 538                                         enum iommu_attr attr, void *data)
 539 {
 540         return -EINVAL;
 541 }
 542
 543 static inline int iommu_domain_set_attr(struct iommu_domain *domain,
 544                                         enum iommu_attr attr, void *data)
 545 {
 546         return -EINVAL;
 547 }
 548
 549 static inline struct device *iommu_device_create(struct device *parent,
 550                                         void *drvdata,
 551                                         const struct attribute_group **groups,
 552                                         const char *fmt, ...)
 553 {
 554         return ERR_PTR(-ENODEV);
 555 }
 556
 557 static inline void iommu_device_destroy(struct device *dev)
 558 {
 559 }
 560
 561 static inline int iommu_device_link(struct device *dev, struct device *link)
 562 {
 563         return -EINVAL;
 564 }
 565
 566 static inline void iommu_device_unlink(struct device *dev, struct device *link)
 567 {
 568 }
 569
 570 static inline int iommu_fwspec_init(struct device *dev,
 571                                     struct fwnode_handle *iommu_fwnode,
 572                                     const struct iommu_ops *ops)
 573 {
 574         return -ENODEV;
 575 }
 576
 577 static inline void iommu_fwspec_free(struct device *dev)
 578 {
 579 }
 580
 581 static inline int iommu_fwspec_add_ids(struct device *dev, u32 *ids,
 582                                        int num_ids)
 583 {
 584         return -ENODEV;
 585 }
 586
 587 static inline void iommu_register_instance(struct fwnode_handle *fwnode,
 588                                            const struct iommu_ops *ops)
 589 {
 590 }
 591
 592 static inline
 593 const struct iommu_ops *iommu_get_instance(struct fwnode_handle *fwnode)
 594 {
 595         return NULL;
 596 }
 597
 598 #endif /* CONFIG_IOMMU_API */
 599
 600 #endif /* __LINUX_IOMMU_H */