1 /* SPDX-License-Identifier: MIT */ 2 #ifndef _DRM_PAGEMAP_H_ 3 #define _DRM_PAGEMAP_H_ 4 5 #include <linux/dma-direction.h> 6 #include <linux/hmm.h> 7 #include <linux/types.h> 8 9 #define NR_PAGES(order) (1U << (order)) 10 11 struct dma_fence; 12 struct drm_pagemap; 13 struct drm_pagemap_cache; 14 struct drm_pagemap_dev_hold; 15 struct drm_pagemap_zdd; 16 struct device; 17 18 /** 19 * enum drm_interconnect_protocol - Used to identify an interconnect protocol. 20 * 21 * @DRM_INTERCONNECT_SYSTEM: DMA map is system pages 22 * @DRM_INTERCONNECT_DRIVER: DMA map is driver defined 23 */ 24 enum drm_interconnect_protocol { 25 DRM_INTERCONNECT_SYSTEM, 26 DRM_INTERCONNECT_DRIVER, 27 /* A driver can add private values beyond DRM_INTERCONNECT_DRIVER */ 28 }; 29 30 /** 31 * struct drm_pagemap_addr - Address representation. 32 * @addr: The dma address or driver-defined address for driver private interconnects. 33 * @proto: The interconnect protocol. 34 * @order: The page order of the device mapping. (Size is PAGE_SIZE << order). 35 * @dir: The DMA direction. 36 * 37 * Note: There is room for improvement here. We should be able to pack into 38 * 64 bits. 39 */ 40 struct drm_pagemap_addr { 41 dma_addr_t addr; 42 u64 proto : 54; 43 u64 order : 8; 44 u64 dir : 2; 45 }; 46 47 /** 48 * drm_pagemap_addr_encode() - Encode a dma address with metadata 49 * @addr: The dma address or driver-defined address for driver private interconnects. 50 * @proto: The interconnect protocol. 51 * @order: The page order of the dma mapping. (Size is PAGE_SIZE << order). 52 * @dir: The DMA direction. 53 * 54 * Return: A struct drm_pagemap_addr encoding the above information. 55 */ 56 static inline struct drm_pagemap_addr 57 drm_pagemap_addr_encode(dma_addr_t addr, 58 enum drm_interconnect_protocol proto, 59 unsigned int order, 60 enum dma_data_direction dir) 61 { 62 return (struct drm_pagemap_addr) { 63 .addr = addr, 64 .proto = proto, 65 .order = order, 66 .dir = dir, 67 }; 68 } 69 70 /** 71 * struct drm_pagemap_ops: Ops for a drm-pagemap. 72 */ 73 struct drm_pagemap_ops { 74 /** 75 * @device_map: Map for device access or provide a virtual address suitable for 76 * 77 * @dpagemap: The struct drm_pagemap for the page. 78 * @dev: The device mapper. 79 * @page: The page to map. 80 * @order: The page order of the device mapping. (Size is PAGE_SIZE << order). 81 * @dir: The transfer direction. 82 */ 83 struct drm_pagemap_addr (*device_map)(struct drm_pagemap *dpagemap, 84 struct device *dev, 85 struct page *page, 86 unsigned int order, 87 enum dma_data_direction dir); 88 89 /** 90 * @device_unmap: Unmap a device address previously obtained using @device_map. 91 * 92 * @dpagemap: The struct drm_pagemap for the mapping. 93 * @dev: The device unmapper. 94 * @addr: The device address obtained when mapping. 95 */ 96 void (*device_unmap)(struct drm_pagemap *dpagemap, 97 struct device *dev, 98 const struct drm_pagemap_addr *addr); 99 100 /** 101 * @populate_mm: Populate part of the mm with @dpagemap memory, 102 * migrating existing data. 103 * @dpagemap: The struct drm_pagemap managing the memory. 104 * @start: The virtual start address in @mm 105 * @end: The virtual end address in @mm 106 * @mm: Pointer to a live mm. The caller must have an mmget() 107 * reference. 108 * 109 * The caller will have the mm lock at least in read mode. 110 * Note that there is no guarantee that the memory is resident 111 * after the function returns, it's best effort only. 112 * When the mm is not using the memory anymore, 113 * it will be released. The struct drm_pagemap might have a 114 * mechanism in place to reclaim the memory and the data will 115 * then be migrated. Typically to system memory. 116 * The implementation should hold sufficient runtime power- 117 * references while pages are used in an address space and 118 * should ideally guard against hardware device unbind in 119 * a way such that device pages are migrated back to system 120 * followed by device page removal. The implementation should 121 * return -ENODEV after device removal. 122 * 123 * Return: 0 if successful. Negative error code on error. 124 */ 125 int (*populate_mm)(struct drm_pagemap *dpagemap, 126 unsigned long start, unsigned long end, 127 struct mm_struct *mm, 128 unsigned long timeslice_ms); 129 /** 130 * @destroy: Destroy the drm_pagemap and associated resources. 131 * @dpagemap: The drm_pagemap to destroy. 132 * @is_atomic_or_reclaim: The function may be called from 133 * atomic- or reclaim context. 134 * 135 * The implementation should take care not to attempt to 136 * destroy resources that may already have been destroyed 137 * using devm_ callbacks, since this function may be called 138 * after the underlying struct device has been unbound. 139 * If the implementation defers the execution to a work item 140 * to avoid locking issues, then it must make sure the work 141 * items are flushed before module exit. If the destroy call 142 * happens after the provider's pci_remove() callback has 143 * been executed, a module reference and drm device reference is 144 * held across the destroy callback. 145 */ 146 void (*destroy)(struct drm_pagemap *dpagemap, 147 bool is_atomic_or_reclaim); 148 }; 149 150 /** 151 * struct drm_pagemap: Additional information for a struct dev_pagemap 152 * used for device p2p handshaking. 153 * @ops: The struct drm_pagemap_ops. 154 * @ref: Reference count. 155 * @drm: The struct drm device owning the device-private memory. 156 * @pagemap: Pointer to the underlying dev_pagemap. 157 * @dev_hold: Pointer to a struct drm_pagemap_dev_hold for 158 * device referencing. 159 * @cache: Back-pointer to the &struct drm_pagemap_cache used for this 160 * &struct drm_pagemap. May be NULL if no cache is used. 161 * @shrink_link: Link into the shrinker's list of drm_pagemaps. Only 162 * used if also using a pagemap cache. 163 */ 164 struct drm_pagemap { 165 const struct drm_pagemap_ops *ops; 166 struct kref ref; 167 struct drm_device *drm; 168 struct dev_pagemap *pagemap; 169 struct drm_pagemap_dev_hold *dev_hold; 170 struct drm_pagemap_cache *cache; 171 struct list_head shrink_link; 172 }; 173 174 struct drm_pagemap_devmem; 175 176 /** 177 * struct drm_pagemap_devmem_ops - Operations structure for GPU SVM device memory 178 * 179 * This structure defines the operations for GPU Shared Virtual Memory (SVM) 180 * device memory. These operations are provided by the GPU driver to manage device memory 181 * allocations and perform operations such as migration between device memory and system 182 * RAM. 183 */ 184 struct drm_pagemap_devmem_ops { 185 /** 186 * @devmem_release: Release device memory allocation (optional) 187 * @devmem_allocation: device memory allocation 188 * 189 * Release device memory allocation and drop a reference to device 190 * memory allocation. 191 */ 192 void (*devmem_release)(struct drm_pagemap_devmem *devmem_allocation); 193 194 /** 195 * @populate_devmem_pfn: Populate device memory PFN (required for migration) 196 * @devmem_allocation: device memory allocation 197 * @npages: Number of pages to populate 198 * @pfn: Array of page frame numbers to populate 199 * 200 * Populate device memory page frame numbers (PFN). 201 * 202 * Return: 0 on success, a negative error code on failure. 203 */ 204 int (*populate_devmem_pfn)(struct drm_pagemap_devmem *devmem_allocation, 205 unsigned long npages, unsigned long *pfn); 206 207 /** 208 * @copy_to_devmem: Copy to device memory (required for migration) 209 * @pages: Pointer to array of device memory pages (destination) 210 * @pagemap_addr: Pointer to array of DMA information (source) 211 * @npages: Number of pages to copy 212 * @pre_migrate_fence: dma-fence to wait for before migration start. 213 * May be NULL. 214 * 215 * Copy pages to device memory. If the order of a @pagemap_addr entry 216 * is greater than 0, the entry is populated but subsequent entries 217 * within the range of that order are not populated. 218 * 219 * Return: 0 on success, a negative error code on failure. 220 */ 221 int (*copy_to_devmem)(struct page **pages, 222 struct drm_pagemap_addr *pagemap_addr, 223 unsigned long npages, 224 struct dma_fence *pre_migrate_fence); 225 226 /** 227 * @copy_to_ram: Copy to system RAM (required for migration) 228 * @pages: Pointer to array of device memory pages (source) 229 * @pagemap_addr: Pointer to array of DMA information (destination) 230 * @npages: Number of pages to copy 231 * @pre_migrate_fence: dma-fence to wait for before migration start. 232 * May be NULL. 233 * 234 * Copy pages to system RAM. If the order of a @pagemap_addr entry 235 * is greater than 0, the entry is populated but subsequent entries 236 * within the range of that order are not populated. 237 * 238 * Return: 0 on success, a negative error code on failure. 239 */ 240 int (*copy_to_ram)(struct page **pages, 241 struct drm_pagemap_addr *pagemap_addr, 242 unsigned long npages, 243 struct dma_fence *pre_migrate_fence); 244 }; 245 246 #if IS_ENABLED(CONFIG_ZONE_DEVICE) 247 248 int drm_pagemap_init(struct drm_pagemap *dpagemap, 249 struct dev_pagemap *pagemap, 250 struct drm_device *drm, 251 const struct drm_pagemap_ops *ops); 252 253 struct drm_pagemap *drm_pagemap_create(struct drm_device *drm, 254 struct dev_pagemap *pagemap, 255 const struct drm_pagemap_ops *ops); 256 257 struct drm_pagemap *drm_pagemap_page_to_dpagemap(struct page *page); 258 259 void drm_pagemap_put(struct drm_pagemap *dpagemap); 260 261 #else 262 263 static inline struct drm_pagemap *drm_pagemap_page_to_dpagemap(struct page *page) 264 { 265 return NULL; 266 } 267 268 static inline void drm_pagemap_put(struct drm_pagemap *dpagemap) 269 { 270 } 271 272 #endif /* IS_ENABLED(CONFIG_ZONE_DEVICE) */ 273 274 /** 275 * drm_pagemap_get() - Obtain a reference on a struct drm_pagemap 276 * @dpagemap: Pointer to the struct drm_pagemap, or NULL. 277 * 278 * Return: Pointer to the struct drm_pagemap, or NULL. 279 */ 280 static inline struct drm_pagemap * 281 drm_pagemap_get(struct drm_pagemap *dpagemap) 282 { 283 if (likely(dpagemap)) 284 kref_get(&dpagemap->ref); 285 286 return dpagemap; 287 } 288 289 /** 290 * drm_pagemap_get_unless_zero() - Obtain a reference on a struct drm_pagemap 291 * unless the current reference count is zero. 292 * @dpagemap: Pointer to the drm_pagemap or NULL. 293 * 294 * Return: A pointer to @dpagemap if the reference count was successfully 295 * incremented. NULL if @dpagemap was NULL, or its refcount was 0. 296 */ 297 static inline struct drm_pagemap * __must_check 298 drm_pagemap_get_unless_zero(struct drm_pagemap *dpagemap) 299 { 300 return (dpagemap && kref_get_unless_zero(&dpagemap->ref)) ? dpagemap : NULL; 301 } 302 303 /** 304 * struct drm_pagemap_devmem - Structure representing a GPU SVM device memory allocation 305 * 306 * @dev: Pointer to the device structure which device memory allocation belongs to 307 * @mm: Pointer to the mm_struct for the address space 308 * @detached: device memory allocations is detached from device pages 309 * @ops: Pointer to the operations structure for GPU SVM device memory 310 * @dpagemap: The struct drm_pagemap of the pages this allocation belongs to. 311 * @size: Size of device memory allocation 312 * @timeslice_expiration: Timeslice expiration in jiffies 313 * @pre_migrate_fence: Fence to wait for or pipeline behind before migration starts. 314 * (May be NULL). 315 */ 316 struct drm_pagemap_devmem { 317 struct device *dev; 318 struct mm_struct *mm; 319 struct completion detached; 320 const struct drm_pagemap_devmem_ops *ops; 321 struct drm_pagemap *dpagemap; 322 size_t size; 323 u64 timeslice_expiration; 324 struct dma_fence *pre_migrate_fence; 325 }; 326 327 /** 328 * struct drm_pagemap_migrate_details - Details to govern migration. 329 * @timeslice_ms: The time requested for the migrated pagemap pages to 330 * be present in @mm before being allowed to be migrated back. 331 * @can_migrate_same_pagemap: Whether the copy function as indicated by 332 * the @source_peer_migrates flag, can migrate device pages within a 333 * single drm_pagemap. 334 * @source_peer_migrates: Whether on p2p migration, The source drm_pagemap 335 * should use the copy_to_ram() callback rather than the destination 336 * drm_pagemap should use the copy_to_devmem() callback. 337 */ 338 struct drm_pagemap_migrate_details { 339 unsigned long timeslice_ms; 340 u32 can_migrate_same_pagemap : 1; 341 u32 source_peer_migrates : 1; 342 }; 343 344 #if IS_ENABLED(CONFIG_ZONE_DEVICE) 345 346 int drm_pagemap_migrate_to_devmem(struct drm_pagemap_devmem *devmem_allocation, 347 struct mm_struct *mm, 348 unsigned long start, unsigned long end, 349 const struct drm_pagemap_migrate_details *mdetails); 350 351 int drm_pagemap_evict_to_ram(struct drm_pagemap_devmem *devmem_allocation); 352 353 const struct dev_pagemap_ops *drm_pagemap_pagemap_ops_get(void); 354 355 void drm_pagemap_devmem_init(struct drm_pagemap_devmem *devmem_allocation, 356 struct device *dev, struct mm_struct *mm, 357 const struct drm_pagemap_devmem_ops *ops, 358 struct drm_pagemap *dpagemap, size_t size, 359 struct dma_fence *pre_migrate_fence); 360 361 int drm_pagemap_populate_mm(struct drm_pagemap *dpagemap, 362 unsigned long start, unsigned long end, 363 struct mm_struct *mm, 364 unsigned long timeslice_ms); 365 366 void drm_pagemap_destroy(struct drm_pagemap *dpagemap, bool is_atomic_or_reclaim); 367 368 int drm_pagemap_reinit(struct drm_pagemap *dpagemap); 369 370 #endif /* IS_ENABLED(CONFIG_ZONE_DEVICE) */ 371 372 #endif 373