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 struct drm_pagemap; 10 struct drm_pagemap_zdd; 11 struct device; 12 13 /** 14 * enum drm_interconnect_protocol - Used to identify an interconnect protocol. 15 * 16 * @DRM_INTERCONNECT_SYSTEM: DMA map is system pages 17 * @DRM_INTERCONNECT_DRIVER: DMA map is driver defined 18 */ 19 enum drm_interconnect_protocol { 20 DRM_INTERCONNECT_SYSTEM, 21 DRM_INTERCONNECT_DRIVER, 22 /* A driver can add private values beyond DRM_INTERCONNECT_DRIVER */ 23 }; 24 25 /** 26 * struct drm_pagemap_device_addr - Device address representation. 27 * @addr: The dma address or driver-defined address for driver private interconnects. 28 * @proto: The interconnect protocol. 29 * @order: The page order of the device mapping. (Size is PAGE_SIZE << order). 30 * @dir: The DMA direction. 31 * 32 * Note: There is room for improvement here. We should be able to pack into 33 * 64 bits. 34 */ 35 struct drm_pagemap_device_addr { 36 dma_addr_t addr; 37 u64 proto : 54; 38 u64 order : 8; 39 u64 dir : 2; 40 }; 41 42 /** 43 * drm_pagemap_device_addr_encode() - Encode a dma address with metadata 44 * @addr: The dma address or driver-defined address for driver private interconnects. 45 * @proto: The interconnect protocol. 46 * @order: The page order of the dma mapping. (Size is PAGE_SIZE << order). 47 * @dir: The DMA direction. 48 * 49 * Return: A struct drm_pagemap_device_addr encoding the above information. 50 */ 51 static inline struct drm_pagemap_device_addr 52 drm_pagemap_device_addr_encode(dma_addr_t addr, 53 enum drm_interconnect_protocol proto, 54 unsigned int order, 55 enum dma_data_direction dir) 56 { 57 return (struct drm_pagemap_device_addr) { 58 .addr = addr, 59 .proto = proto, 60 .order = order, 61 .dir = dir, 62 }; 63 } 64 65 /** 66 * struct drm_pagemap_ops: Ops for a drm-pagemap. 67 */ 68 struct drm_pagemap_ops { 69 /** 70 * @device_map: Map for device access or provide a virtual address suitable for 71 * 72 * @dpagemap: The struct drm_pagemap for the page. 73 * @dev: The device mapper. 74 * @page: The page to map. 75 * @order: The page order of the device mapping. (Size is PAGE_SIZE << order). 76 * @dir: The transfer direction. 77 */ 78 struct drm_pagemap_device_addr (*device_map)(struct drm_pagemap *dpagemap, 79 struct device *dev, 80 struct page *page, 81 unsigned int order, 82 enum dma_data_direction dir); 83 84 /** 85 * @device_unmap: Unmap a device address previously obtained using @device_map. 86 * 87 * @dpagemap: The struct drm_pagemap for the mapping. 88 * @dev: The device unmapper. 89 * @addr: The device address obtained when mapping. 90 */ 91 void (*device_unmap)(struct drm_pagemap *dpagemap, 92 struct device *dev, 93 struct drm_pagemap_device_addr addr); 94 95 /** 96 * @populate_mm: Populate part of the mm with @dpagemap memory, 97 * migrating existing data. 98 * @dpagemap: The struct drm_pagemap managing the memory. 99 * @start: The virtual start address in @mm 100 * @end: The virtual end address in @mm 101 * @mm: Pointer to a live mm. The caller must have an mmget() 102 * reference. 103 * 104 * The caller will have the mm lock at least in read mode. 105 * Note that there is no guarantee that the memory is resident 106 * after the function returns, it's best effort only. 107 * When the mm is not using the memory anymore, 108 * it will be released. The struct drm_pagemap might have a 109 * mechanism in place to reclaim the memory and the data will 110 * then be migrated. Typically to system memory. 111 * The implementation should hold sufficient runtime power- 112 * references while pages are used in an address space and 113 * should ideally guard against hardware device unbind in 114 * a way such that device pages are migrated back to system 115 * followed by device page removal. The implementation should 116 * return -ENODEV after device removal. 117 * 118 * Return: 0 if successful. Negative error code on error. 119 */ 120 int (*populate_mm)(struct drm_pagemap *dpagemap, 121 unsigned long start, unsigned long end, 122 struct mm_struct *mm, 123 unsigned long timeslice_ms); 124 }; 125 126 /** 127 * struct drm_pagemap: Additional information for a struct dev_pagemap 128 * used for device p2p handshaking. 129 * @ops: The struct drm_pagemap_ops. 130 * @dev: The struct drevice owning the device-private memory. 131 */ 132 struct drm_pagemap { 133 const struct drm_pagemap_ops *ops; 134 struct device *dev; 135 }; 136 137 struct drm_pagemap_devmem; 138 139 /** 140 * struct drm_pagemap_devmem_ops - Operations structure for GPU SVM device memory 141 * 142 * This structure defines the operations for GPU Shared Virtual Memory (SVM) 143 * device memory. These operations are provided by the GPU driver to manage device memory 144 * allocations and perform operations such as migration between device memory and system 145 * RAM. 146 */ 147 struct drm_pagemap_devmem_ops { 148 /** 149 * @devmem_release: Release device memory allocation (optional) 150 * @devmem_allocation: device memory allocation 151 * 152 * Release device memory allocation and drop a reference to device 153 * memory allocation. 154 */ 155 void (*devmem_release)(struct drm_pagemap_devmem *devmem_allocation); 156 157 /** 158 * @populate_devmem_pfn: Populate device memory PFN (required for migration) 159 * @devmem_allocation: device memory allocation 160 * @npages: Number of pages to populate 161 * @pfn: Array of page frame numbers to populate 162 * 163 * Populate device memory page frame numbers (PFN). 164 * 165 * Return: 0 on success, a negative error code on failure. 166 */ 167 int (*populate_devmem_pfn)(struct drm_pagemap_devmem *devmem_allocation, 168 unsigned long npages, unsigned long *pfn); 169 170 /** 171 * @copy_to_devmem: Copy to device memory (required for migration) 172 * @pages: Pointer to array of device memory pages (destination) 173 * @dma_addr: Pointer to array of DMA addresses (source) 174 * @npages: Number of pages to copy 175 * 176 * Copy pages to device memory. 177 * 178 * Return: 0 on success, a negative error code on failure. 179 */ 180 int (*copy_to_devmem)(struct page **pages, 181 dma_addr_t *dma_addr, 182 unsigned long npages); 183 184 /** 185 * @copy_to_ram: Copy to system RAM (required for migration) 186 * @pages: Pointer to array of device memory pages (source) 187 * @dma_addr: Pointer to array of DMA addresses (destination) 188 * @npages: Number of pages to copy 189 * 190 * Copy pages to system RAM. 191 * 192 * Return: 0 on success, a negative error code on failure. 193 */ 194 int (*copy_to_ram)(struct page **pages, 195 dma_addr_t *dma_addr, 196 unsigned long npages); 197 }; 198 199 /** 200 * struct drm_pagemap_devmem - Structure representing a GPU SVM device memory allocation 201 * 202 * @dev: Pointer to the device structure which device memory allocation belongs to 203 * @mm: Pointer to the mm_struct for the address space 204 * @detached: device memory allocations is detached from device pages 205 * @ops: Pointer to the operations structure for GPU SVM device memory 206 * @dpagemap: The struct drm_pagemap of the pages this allocation belongs to. 207 * @size: Size of device memory allocation 208 * @timeslice_expiration: Timeslice expiration in jiffies 209 */ 210 struct drm_pagemap_devmem { 211 struct device *dev; 212 struct mm_struct *mm; 213 struct completion detached; 214 const struct drm_pagemap_devmem_ops *ops; 215 struct drm_pagemap *dpagemap; 216 size_t size; 217 u64 timeslice_expiration; 218 }; 219 220 int drm_pagemap_migrate_to_devmem(struct drm_pagemap_devmem *devmem_allocation, 221 struct mm_struct *mm, 222 unsigned long start, unsigned long end, 223 unsigned long timeslice_ms, 224 void *pgmap_owner); 225 226 int drm_pagemap_evict_to_ram(struct drm_pagemap_devmem *devmem_allocation); 227 228 const struct dev_pagemap_ops *drm_pagemap_pagemap_ops_get(void); 229 230 struct drm_pagemap *drm_pagemap_page_to_dpagemap(struct page *page); 231 232 void drm_pagemap_devmem_init(struct drm_pagemap_devmem *devmem_allocation, 233 struct device *dev, struct mm_struct *mm, 234 const struct drm_pagemap_devmem_ops *ops, 235 struct drm_pagemap *dpagemap, size_t size); 236 237 int drm_pagemap_populate_mm(struct drm_pagemap *dpagemap, 238 unsigned long start, unsigned long end, 239 struct mm_struct *mm, 240 unsigned long timeslice_ms); 241 242 #endif 243