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_CMA_SIZE_PERCENTAGE 73 74 static phys_addr_t __init __maybe_unused cma_early_percent_memory(void) 75 { 76 struct memblock_region *reg; 77 unsigned long total_pages = 0; 78 79 /* 80 * We cannot use memblock_phys_mem_size() here, because 81 * memblock_analyze() has not been called yet. 82 */ 83 for_each_memblock(memory, reg) 84 total_pages += memblock_region_memory_end_pfn(reg) - 85 memblock_region_memory_base_pfn(reg); 86 87 return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT; 88 } 89 90 #else 91 92 static inline __maybe_unused phys_addr_t cma_early_percent_memory(void) 93 { 94 return 0; 95 } 96 97 #endif 98 99 /** 100 * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling 101 * @limit: End address of the reserved memory (optional, 0 for any). 102 * 103 * This function reserves memory from early allocator. It should be 104 * called by arch specific code once the early allocator (memblock or bootmem) 105 * has been activated and all other subsystems have already allocated/reserved 106 * memory. 107 */ 108 void __init dma_contiguous_reserve(phys_addr_t limit) 109 { 110 phys_addr_t selected_size = 0; 111 phys_addr_t selected_base = 0; 112 phys_addr_t selected_limit = limit; 113 bool fixed = false; 114 115 pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit); 116 117 if (size_cmdline != -1) { 118 selected_size = size_cmdline; 119 selected_base = base_cmdline; 120 selected_limit = min_not_zero(limit_cmdline, limit); 121 if (base_cmdline + size_cmdline == limit_cmdline) 122 fixed = true; 123 } else { 124 #ifdef CONFIG_CMA_SIZE_SEL_MBYTES 125 selected_size = size_bytes; 126 #elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE) 127 selected_size = cma_early_percent_memory(); 128 #elif defined(CONFIG_CMA_SIZE_SEL_MIN) 129 selected_size = min(size_bytes, cma_early_percent_memory()); 130 #elif defined(CONFIG_CMA_SIZE_SEL_MAX) 131 selected_size = max(size_bytes, cma_early_percent_memory()); 132 #endif 133 } 134 135 if (selected_size && !dma_contiguous_default_area) { 136 pr_debug("%s: reserving %ld MiB for global area\n", __func__, 137 (unsigned long)selected_size / SZ_1M); 138 139 dma_contiguous_reserve_area(selected_size, selected_base, 140 selected_limit, 141 &dma_contiguous_default_area, 142 fixed); 143 } 144 } 145 146 /** 147 * dma_contiguous_reserve_area() - reserve custom contiguous area 148 * @size: Size of the reserved area (in bytes), 149 * @base: Base address of the reserved area optional, use 0 for any 150 * @limit: End address of the reserved memory (optional, 0 for any). 151 * @res_cma: Pointer to store the created cma region. 152 * @fixed: hint about where to place the reserved area 153 * 154 * This function reserves memory from early allocator. It should be 155 * called by arch specific code once the early allocator (memblock or bootmem) 156 * has been activated and all other subsystems have already allocated/reserved 157 * memory. This function allows to create custom reserved areas for specific 158 * devices. 159 * 160 * If @fixed is true, reserve contiguous area at exactly @base. If false, 161 * reserve in range from @base to @limit. 162 */ 163 int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, 164 phys_addr_t limit, struct cma **res_cma, 165 bool fixed) 166 { 167 int ret; 168 169 ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed, 170 "reserved", res_cma); 171 if (ret) 172 return ret; 173 174 /* Architecture specific contiguous memory fixup. */ 175 dma_contiguous_early_fixup(cma_get_base(*res_cma), 176 cma_get_size(*res_cma)); 177 178 return 0; 179 } 180 181 /** 182 * dma_alloc_from_contiguous() - allocate pages from contiguous area 183 * @dev: Pointer to device for which the allocation is performed. 184 * @count: Requested number of pages. 185 * @align: Requested alignment of pages (in PAGE_SIZE order). 186 * @no_warn: Avoid printing message about failed allocation. 187 * 188 * This function allocates memory buffer for specified device. It uses 189 * device specific contiguous memory area if available or the default 190 * global one. Requires architecture specific dev_get_cma_area() helper 191 * function. 192 */ 193 struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, 194 unsigned int align, bool no_warn) 195 { 196 if (align > CONFIG_CMA_ALIGNMENT) 197 align = CONFIG_CMA_ALIGNMENT; 198 199 return cma_alloc(dev_get_cma_area(dev), count, align, no_warn); 200 } 201 202 /** 203 * dma_release_from_contiguous() - release allocated pages 204 * @dev: Pointer to device for which the pages were allocated. 205 * @pages: Allocated pages. 206 * @count: Number of allocated pages. 207 * 208 * This function releases memory allocated by dma_alloc_from_contiguous(). 209 * It returns false when provided pages do not belong to contiguous area and 210 * true otherwise. 211 */ 212 bool dma_release_from_contiguous(struct device *dev, struct page *pages, 213 int count) 214 { 215 return cma_release(dev_get_cma_area(dev), pages, count); 216 } 217 218 /** 219 * dma_alloc_contiguous() - allocate contiguous pages 220 * @dev: Pointer to device for which the allocation is performed. 221 * @size: Requested allocation size. 222 * @gfp: Allocation flags. 223 * 224 * This function allocates contiguous memory buffer for specified device. It 225 * tries to use device specific contiguous memory area if available, or the 226 * default global one. 227 * 228 * Note that it byapss one-page size of allocations from the global area as 229 * the addresses within one page are always contiguous, so there is no need 230 * to waste CMA pages for that kind; it also helps reduce fragmentations. 231 */ 232 struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) 233 { 234 size_t count = size >> PAGE_SHIFT; 235 struct page *page = NULL; 236 struct cma *cma = NULL; 237 238 if (dev && dev->cma_area) 239 cma = dev->cma_area; 240 else if (count > 1) 241 cma = dma_contiguous_default_area; 242 243 /* CMA can be used only in the context which permits sleeping */ 244 if (cma && gfpflags_allow_blocking(gfp)) { 245 size_t align = get_order(size); 246 size_t cma_align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT); 247 248 page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN); 249 } 250 251 return page; 252 } 253 254 /** 255 * dma_free_contiguous() - release allocated pages 256 * @dev: Pointer to device for which the pages were allocated. 257 * @page: Pointer to the allocated pages. 258 * @size: Size of allocated pages. 259 * 260 * This function releases memory allocated by dma_alloc_contiguous(). As the 261 * cma_release returns false when provided pages do not belong to contiguous 262 * area and true otherwise, this function then does a fallback __free_pages() 263 * upon a false-return. 264 */ 265 void dma_free_contiguous(struct device *dev, struct page *page, size_t size) 266 { 267 if (!cma_release(dev_get_cma_area(dev), page, 268 PAGE_ALIGN(size) >> PAGE_SHIFT)) 269 __free_pages(page, get_order(size)); 270 } 271 272 /* 273 * Support for reserved memory regions defined in device tree 274 */ 275 #ifdef CONFIG_OF_RESERVED_MEM 276 #include <linux/of.h> 277 #include <linux/of_fdt.h> 278 #include <linux/of_reserved_mem.h> 279 280 #undef pr_fmt 281 #define pr_fmt(fmt) fmt 282 283 static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev) 284 { 285 dev_set_cma_area(dev, rmem->priv); 286 return 0; 287 } 288 289 static void rmem_cma_device_release(struct reserved_mem *rmem, 290 struct device *dev) 291 { 292 dev_set_cma_area(dev, NULL); 293 } 294 295 static const struct reserved_mem_ops rmem_cma_ops = { 296 .device_init = rmem_cma_device_init, 297 .device_release = rmem_cma_device_release, 298 }; 299 300 static int __init rmem_cma_setup(struct reserved_mem *rmem) 301 { 302 phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order); 303 phys_addr_t mask = align - 1; 304 unsigned long node = rmem->fdt_node; 305 bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL); 306 struct cma *cma; 307 int err; 308 309 if (size_cmdline != -1 && default_cma) { 310 pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n", 311 rmem->name); 312 return -EBUSY; 313 } 314 315 if (!of_get_flat_dt_prop(node, "reusable", NULL) || 316 of_get_flat_dt_prop(node, "no-map", NULL)) 317 return -EINVAL; 318 319 if ((rmem->base & mask) || (rmem->size & mask)) { 320 pr_err("Reserved memory: incorrect alignment of CMA region\n"); 321 return -EINVAL; 322 } 323 324 err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma); 325 if (err) { 326 pr_err("Reserved memory: unable to setup CMA region\n"); 327 return err; 328 } 329 /* Architecture specific contiguous memory fixup. */ 330 dma_contiguous_early_fixup(rmem->base, rmem->size); 331 332 if (default_cma) 333 dma_contiguous_set_default(cma); 334 335 rmem->ops = &rmem_cma_ops; 336 rmem->priv = cma; 337 338 pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n", 339 &rmem->base, (unsigned long)rmem->size / SZ_1M); 340 341 return 0; 342 } 343 RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup); 344 #endif 345