1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Contiguous Memory Allocator for DMA mapping framework 4 * Copyright (c) 2010-2011 by Samsung Electronics. 5 * Written by: 6 * Marek Szyprowski <m.szyprowski@samsung.com> 7 * Michal Nazarewicz <mina86@mina86.com> 8 */ 9 10 #define pr_fmt(fmt) "cma: " fmt 11 12 #ifdef CONFIG_CMA_DEBUG 13 #ifndef DEBUG 14 # define DEBUG 15 #endif 16 #endif 17 18 #include <asm/page.h> 19 #include <asm/dma-contiguous.h> 20 21 #include <linux/memblock.h> 22 #include <linux/err.h> 23 #include <linux/sizes.h> 24 #include <linux/dma-contiguous.h> 25 #include <linux/cma.h> 26 27 #ifdef CONFIG_CMA_SIZE_MBYTES 28 #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES 29 #else 30 #define CMA_SIZE_MBYTES 0 31 #endif 32 33 struct cma *dma_contiguous_default_area; 34 35 /* 36 * Default global CMA area size can be defined in kernel's .config. 37 * This is useful mainly for distro maintainers to create a kernel 38 * that works correctly for most supported systems. 39 * The size can be set in bytes or as a percentage of the total memory 40 * in the system. 41 * 42 * Users, who want to set the size of global CMA area for their system 43 * should use cma= kernel parameter. 44 */ 45 static const phys_addr_t size_bytes __initconst = 46 (phys_addr_t)CMA_SIZE_MBYTES * SZ_1M; 47 static phys_addr_t size_cmdline __initdata = -1; 48 static phys_addr_t base_cmdline __initdata; 49 static phys_addr_t limit_cmdline __initdata; 50 51 static int __init early_cma(char *p) 52 { 53 if (!p) { 54 pr_err("Config string not provided\n"); 55 return -EINVAL; 56 } 57 58 size_cmdline = memparse(p, &p); 59 if (*p != '@') 60 return 0; 61 base_cmdline = memparse(p + 1, &p); 62 if (*p != '-') { 63 limit_cmdline = base_cmdline + size_cmdline; 64 return 0; 65 } 66 limit_cmdline = memparse(p + 1, &p); 67 68 return 0; 69 } 70 early_param("cma", early_cma); 71 72 #ifdef CONFIG_DMA_PERNUMA_CMA 73 74 static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES]; 75 static phys_addr_t pernuma_size_bytes __initdata; 76 77 static int __init early_cma_pernuma(char *p) 78 { 79 pernuma_size_bytes = memparse(p, &p); 80 return 0; 81 } 82 early_param("cma_pernuma", early_cma_pernuma); 83 #endif 84 85 #ifdef CONFIG_CMA_SIZE_PERCENTAGE 86 87 static phys_addr_t __init __maybe_unused cma_early_percent_memory(void) 88 { 89 struct memblock_region *reg; 90 unsigned long total_pages = 0; 91 92 /* 93 * We cannot use memblock_phys_mem_size() here, because 94 * memblock_analyze() has not been called yet. 95 */ 96 for_each_memblock(memory, reg) 97 total_pages += memblock_region_memory_end_pfn(reg) - 98 memblock_region_memory_base_pfn(reg); 99 100 return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT; 101 } 102 103 #else 104 105 static inline __maybe_unused phys_addr_t cma_early_percent_memory(void) 106 { 107 return 0; 108 } 109 110 #endif 111 112 #ifdef CONFIG_DMA_PERNUMA_CMA 113 void __init dma_pernuma_cma_reserve(void) 114 { 115 int nid; 116 117 if (!pernuma_size_bytes) 118 return; 119 120 for_each_online_node(nid) { 121 int ret; 122 char name[CMA_MAX_NAME]; 123 struct cma **cma = &dma_contiguous_pernuma_area[nid]; 124 125 snprintf(name, sizeof(name), "pernuma%d", nid); 126 ret = cma_declare_contiguous_nid(0, pernuma_size_bytes, 0, 0, 127 0, false, name, cma, nid); 128 if (ret) { 129 pr_warn("%s: reservation failed: err %d, node %d", __func__, 130 ret, nid); 131 continue; 132 } 133 134 pr_debug("%s: reserved %llu MiB on node %d\n", __func__, 135 (unsigned long long)pernuma_size_bytes / SZ_1M, nid); 136 } 137 } 138 #endif 139 140 /** 141 * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling 142 * @limit: End address of the reserved memory (optional, 0 for any). 143 * 144 * This function reserves memory from early allocator. It should be 145 * called by arch specific code once the early allocator (memblock or bootmem) 146 * has been activated and all other subsystems have already allocated/reserved 147 * memory. 148 */ 149 void __init dma_contiguous_reserve(phys_addr_t limit) 150 { 151 phys_addr_t selected_size = 0; 152 phys_addr_t selected_base = 0; 153 phys_addr_t selected_limit = limit; 154 bool fixed = false; 155 156 pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit); 157 158 if (size_cmdline != -1) { 159 selected_size = size_cmdline; 160 selected_base = base_cmdline; 161 selected_limit = min_not_zero(limit_cmdline, limit); 162 if (base_cmdline + size_cmdline == limit_cmdline) 163 fixed = true; 164 } else { 165 #ifdef CONFIG_CMA_SIZE_SEL_MBYTES 166 selected_size = size_bytes; 167 #elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE) 168 selected_size = cma_early_percent_memory(); 169 #elif defined(CONFIG_CMA_SIZE_SEL_MIN) 170 selected_size = min(size_bytes, cma_early_percent_memory()); 171 #elif defined(CONFIG_CMA_SIZE_SEL_MAX) 172 selected_size = max(size_bytes, cma_early_percent_memory()); 173 #endif 174 } 175 176 if (selected_size && !dma_contiguous_default_area) { 177 pr_debug("%s: reserving %ld MiB for global area\n", __func__, 178 (unsigned long)selected_size / SZ_1M); 179 180 dma_contiguous_reserve_area(selected_size, selected_base, 181 selected_limit, 182 &dma_contiguous_default_area, 183 fixed); 184 } 185 } 186 187 /** 188 * dma_contiguous_reserve_area() - reserve custom contiguous area 189 * @size: Size of the reserved area (in bytes), 190 * @base: Base address of the reserved area optional, use 0 for any 191 * @limit: End address of the reserved memory (optional, 0 for any). 192 * @res_cma: Pointer to store the created cma region. 193 * @fixed: hint about where to place the reserved area 194 * 195 * This function reserves memory from early allocator. It should be 196 * called by arch specific code once the early allocator (memblock or bootmem) 197 * has been activated and all other subsystems have already allocated/reserved 198 * memory. This function allows to create custom reserved areas for specific 199 * devices. 200 * 201 * If @fixed is true, reserve contiguous area at exactly @base. If false, 202 * reserve in range from @base to @limit. 203 */ 204 int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, 205 phys_addr_t limit, struct cma **res_cma, 206 bool fixed) 207 { 208 int ret; 209 210 ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed, 211 "reserved", res_cma); 212 if (ret) 213 return ret; 214 215 /* Architecture specific contiguous memory fixup. */ 216 dma_contiguous_early_fixup(cma_get_base(*res_cma), 217 cma_get_size(*res_cma)); 218 219 return 0; 220 } 221 222 /** 223 * dma_alloc_from_contiguous() - allocate pages from contiguous area 224 * @dev: Pointer to device for which the allocation is performed. 225 * @count: Requested number of pages. 226 * @align: Requested alignment of pages (in PAGE_SIZE order). 227 * @no_warn: Avoid printing message about failed allocation. 228 * 229 * This function allocates memory buffer for specified device. It uses 230 * device specific contiguous memory area if available or the default 231 * global one. Requires architecture specific dev_get_cma_area() helper 232 * function. 233 */ 234 struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, 235 unsigned int align, bool no_warn) 236 { 237 if (align > CONFIG_CMA_ALIGNMENT) 238 align = CONFIG_CMA_ALIGNMENT; 239 240 return cma_alloc(dev_get_cma_area(dev), count, align, no_warn); 241 } 242 243 /** 244 * dma_release_from_contiguous() - release allocated pages 245 * @dev: Pointer to device for which the pages were allocated. 246 * @pages: Allocated pages. 247 * @count: Number of allocated pages. 248 * 249 * This function releases memory allocated by dma_alloc_from_contiguous(). 250 * It returns false when provided pages do not belong to contiguous area and 251 * true otherwise. 252 */ 253 bool dma_release_from_contiguous(struct device *dev, struct page *pages, 254 int count) 255 { 256 return cma_release(dev_get_cma_area(dev), pages, count); 257 } 258 259 static struct page *cma_alloc_aligned(struct cma *cma, size_t size, gfp_t gfp) 260 { 261 unsigned int align = min(get_order(size), CONFIG_CMA_ALIGNMENT); 262 263 return cma_alloc(cma, size >> PAGE_SHIFT, align, gfp & __GFP_NOWARN); 264 } 265 266 /** 267 * dma_alloc_contiguous() - allocate contiguous pages 268 * @dev: Pointer to device for which the allocation is performed. 269 * @size: Requested allocation size. 270 * @gfp: Allocation flags. 271 * 272 * tries to use device specific contiguous memory area if available, or it 273 * tries to use per-numa cma, if the allocation fails, it will fallback to 274 * try default global one. 275 * 276 * Note that it bypass one-page size of allocations from the per-numa and 277 * global area as the addresses within one page are always contiguous, so 278 * there is no need to waste CMA pages for that kind; it also helps reduce 279 * fragmentations. 280 */ 281 struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) 282 { 283 #ifdef CONFIG_DMA_PERNUMA_CMA 284 int nid = dev_to_node(dev); 285 #endif 286 287 /* CMA can be used only in the context which permits sleeping */ 288 if (!gfpflags_allow_blocking(gfp)) 289 return NULL; 290 if (dev->cma_area) 291 return cma_alloc_aligned(dev->cma_area, size, gfp); 292 if (size <= PAGE_SIZE) 293 return NULL; 294 295 #ifdef CONFIG_DMA_PERNUMA_CMA 296 if (nid != NUMA_NO_NODE && !(gfp & (GFP_DMA | GFP_DMA32))) { 297 struct cma *cma = dma_contiguous_pernuma_area[nid]; 298 struct page *page; 299 300 if (cma) { 301 page = cma_alloc_aligned(cma, size, gfp); 302 if (page) 303 return page; 304 } 305 } 306 #endif 307 if (!dma_contiguous_default_area) 308 return NULL; 309 310 return cma_alloc_aligned(dma_contiguous_default_area, size, gfp); 311 } 312 313 /** 314 * dma_free_contiguous() - release allocated pages 315 * @dev: Pointer to device for which the pages were allocated. 316 * @page: Pointer to the allocated pages. 317 * @size: Size of allocated pages. 318 * 319 * This function releases memory allocated by dma_alloc_contiguous(). As the 320 * cma_release returns false when provided pages do not belong to contiguous 321 * area and true otherwise, this function then does a fallback __free_pages() 322 * upon a false-return. 323 */ 324 void dma_free_contiguous(struct device *dev, struct page *page, size_t size) 325 { 326 unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; 327 328 /* if dev has its own cma, free page from there */ 329 if (dev->cma_area) { 330 if (cma_release(dev->cma_area, page, count)) 331 return; 332 } else { 333 /* 334 * otherwise, page is from either per-numa cma or default cma 335 */ 336 #ifdef CONFIG_DMA_PERNUMA_CMA 337 if (cma_release(dma_contiguous_pernuma_area[page_to_nid(page)], 338 page, count)) 339 return; 340 #endif 341 if (cma_release(dma_contiguous_default_area, page, count)) 342 return; 343 } 344 345 /* not in any cma, free from buddy */ 346 __free_pages(page, get_order(size)); 347 } 348 349 /* 350 * Support for reserved memory regions defined in device tree 351 */ 352 #ifdef CONFIG_OF_RESERVED_MEM 353 #include <linux/of.h> 354 #include <linux/of_fdt.h> 355 #include <linux/of_reserved_mem.h> 356 357 #undef pr_fmt 358 #define pr_fmt(fmt) fmt 359 360 static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev) 361 { 362 dev_set_cma_area(dev, rmem->priv); 363 return 0; 364 } 365 366 static void rmem_cma_device_release(struct reserved_mem *rmem, 367 struct device *dev) 368 { 369 dev_set_cma_area(dev, NULL); 370 } 371 372 static const struct reserved_mem_ops rmem_cma_ops = { 373 .device_init = rmem_cma_device_init, 374 .device_release = rmem_cma_device_release, 375 }; 376 377 static int __init rmem_cma_setup(struct reserved_mem *rmem) 378 { 379 phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order); 380 phys_addr_t mask = align - 1; 381 unsigned long node = rmem->fdt_node; 382 bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL); 383 struct cma *cma; 384 int err; 385 386 if (size_cmdline != -1 && default_cma) { 387 pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n", 388 rmem->name); 389 return -EBUSY; 390 } 391 392 if (!of_get_flat_dt_prop(node, "reusable", NULL) || 393 of_get_flat_dt_prop(node, "no-map", NULL)) 394 return -EINVAL; 395 396 if ((rmem->base & mask) || (rmem->size & mask)) { 397 pr_err("Reserved memory: incorrect alignment of CMA region\n"); 398 return -EINVAL; 399 } 400 401 err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma); 402 if (err) { 403 pr_err("Reserved memory: unable to setup CMA region\n"); 404 return err; 405 } 406 /* Architecture specific contiguous memory fixup. */ 407 dma_contiguous_early_fixup(rmem->base, rmem->size); 408 409 if (default_cma) 410 dma_contiguous_set_default(cma); 411 412 rmem->ops = &rmem_cma_ops; 413 rmem->priv = cma; 414 415 pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n", 416 &rmem->base, (unsigned long)rmem->size / SZ_1M); 417 418 return 0; 419 } 420 RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup); 421 #endif 422