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 = (phys_addr_t)CMA_SIZE_MBYTES * SZ_1M; 46 static phys_addr_t size_cmdline = -1; 47 static phys_addr_t base_cmdline; 48 static phys_addr_t limit_cmdline; 49 50 static int __init early_cma(char *p) 51 { 52 if (!p) { 53 pr_err("Config string not provided\n"); 54 return -EINVAL; 55 } 56 57 size_cmdline = memparse(p, &p); 58 if (*p != '@') 59 return 0; 60 base_cmdline = memparse(p + 1, &p); 61 if (*p != '-') { 62 limit_cmdline = base_cmdline + size_cmdline; 63 return 0; 64 } 65 limit_cmdline = memparse(p + 1, &p); 66 67 return 0; 68 } 69 early_param("cma", early_cma); 70 71 #ifdef CONFIG_CMA_SIZE_PERCENTAGE 72 73 static phys_addr_t __init __maybe_unused cma_early_percent_memory(void) 74 { 75 struct memblock_region *reg; 76 unsigned long total_pages = 0; 77 78 /* 79 * We cannot use memblock_phys_mem_size() here, because 80 * memblock_analyze() has not been called yet. 81 */ 82 for_each_memblock(memory, reg) 83 total_pages += memblock_region_memory_end_pfn(reg) - 84 memblock_region_memory_base_pfn(reg); 85 86 return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT; 87 } 88 89 #else 90 91 static inline __maybe_unused phys_addr_t cma_early_percent_memory(void) 92 { 93 return 0; 94 } 95 96 #endif 97 98 /** 99 * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling 100 * @limit: End address of the reserved memory (optional, 0 for any). 101 * 102 * This function reserves memory from early allocator. It should be 103 * called by arch specific code once the early allocator (memblock or bootmem) 104 * has been activated and all other subsystems have already allocated/reserved 105 * memory. 106 */ 107 void __init dma_contiguous_reserve(phys_addr_t limit) 108 { 109 phys_addr_t selected_size = 0; 110 phys_addr_t selected_base = 0; 111 phys_addr_t selected_limit = limit; 112 bool fixed = false; 113 114 pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit); 115 116 if (size_cmdline != -1) { 117 selected_size = size_cmdline; 118 selected_base = base_cmdline; 119 selected_limit = min_not_zero(limit_cmdline, limit); 120 if (base_cmdline + size_cmdline == limit_cmdline) 121 fixed = true; 122 } else { 123 #ifdef CONFIG_CMA_SIZE_SEL_MBYTES 124 selected_size = size_bytes; 125 #elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE) 126 selected_size = cma_early_percent_memory(); 127 #elif defined(CONFIG_CMA_SIZE_SEL_MIN) 128 selected_size = min(size_bytes, cma_early_percent_memory()); 129 #elif defined(CONFIG_CMA_SIZE_SEL_MAX) 130 selected_size = max(size_bytes, cma_early_percent_memory()); 131 #endif 132 } 133 134 if (selected_size && !dma_contiguous_default_area) { 135 pr_debug("%s: reserving %ld MiB for global area\n", __func__, 136 (unsigned long)selected_size / SZ_1M); 137 138 dma_contiguous_reserve_area(selected_size, selected_base, 139 selected_limit, 140 &dma_contiguous_default_area, 141 fixed); 142 } 143 } 144 145 /** 146 * dma_contiguous_reserve_area() - reserve custom contiguous area 147 * @size: Size of the reserved area (in bytes), 148 * @base: Base address of the reserved area optional, use 0 for any 149 * @limit: End address of the reserved memory (optional, 0 for any). 150 * @res_cma: Pointer to store the created cma region. 151 * @fixed: hint about where to place the reserved area 152 * 153 * This function reserves memory from early allocator. It should be 154 * called by arch specific code once the early allocator (memblock or bootmem) 155 * has been activated and all other subsystems have already allocated/reserved 156 * memory. This function allows to create custom reserved areas for specific 157 * devices. 158 * 159 * If @fixed is true, reserve contiguous area at exactly @base. If false, 160 * reserve in range from @base to @limit. 161 */ 162 int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base, 163 phys_addr_t limit, struct cma **res_cma, 164 bool fixed) 165 { 166 int ret; 167 168 ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed, 169 "reserved", res_cma); 170 if (ret) 171 return ret; 172 173 /* Architecture specific contiguous memory fixup. */ 174 dma_contiguous_early_fixup(cma_get_base(*res_cma), 175 cma_get_size(*res_cma)); 176 177 return 0; 178 } 179 180 /** 181 * dma_alloc_from_contiguous() - allocate pages from contiguous area 182 * @dev: Pointer to device for which the allocation is performed. 183 * @count: Requested number of pages. 184 * @align: Requested alignment of pages (in PAGE_SIZE order). 185 * @no_warn: Avoid printing message about failed allocation. 186 * 187 * This function allocates memory buffer for specified device. It uses 188 * device specific contiguous memory area if available or the default 189 * global one. Requires architecture specific dev_get_cma_area() helper 190 * function. 191 */ 192 struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, 193 unsigned int align, bool no_warn) 194 { 195 if (align > CONFIG_CMA_ALIGNMENT) 196 align = CONFIG_CMA_ALIGNMENT; 197 198 return cma_alloc(dev_get_cma_area(dev), count, align, no_warn); 199 } 200 201 /** 202 * dma_release_from_contiguous() - release allocated pages 203 * @dev: Pointer to device for which the pages were allocated. 204 * @pages: Allocated pages. 205 * @count: Number of allocated pages. 206 * 207 * This function releases memory allocated by dma_alloc_from_contiguous(). 208 * It returns false when provided pages do not belong to contiguous area and 209 * true otherwise. 210 */ 211 bool dma_release_from_contiguous(struct device *dev, struct page *pages, 212 int count) 213 { 214 return cma_release(dev_get_cma_area(dev), pages, count); 215 } 216 217 /** 218 * dma_alloc_contiguous() - allocate contiguous pages 219 * @dev: Pointer to device for which the allocation is performed. 220 * @size: Requested allocation size. 221 * @gfp: Allocation flags. 222 * 223 * This function allocates contiguous memory buffer for specified device. It 224 * first tries to use device specific contiguous memory area if available or 225 * the default global one, then tries a fallback allocation of normal pages. 226 * 227 * Note that it byapss one-page size of allocations from the global area as 228 * the addresses within one page are always contiguous, so there is no need 229 * to waste CMA pages for that kind; it also helps reduce fragmentations. 230 */ 231 struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) 232 { 233 size_t count = size >> PAGE_SHIFT; 234 struct page *page = NULL; 235 struct cma *cma = NULL; 236 237 if (dev && dev->cma_area) 238 cma = dev->cma_area; 239 else if (count > 1) 240 cma = dma_contiguous_default_area; 241 242 /* CMA can be used only in the context which permits sleeping */ 243 if (cma && gfpflags_allow_blocking(gfp)) { 244 size_t align = get_order(size); 245 size_t cma_align = min_t(size_t, align, CONFIG_CMA_ALIGNMENT); 246 247 page = cma_alloc(cma, count, cma_align, gfp & __GFP_NOWARN); 248 } 249 250 return page; 251 } 252 253 /** 254 * dma_free_contiguous() - release allocated pages 255 * @dev: Pointer to device for which the pages were allocated. 256 * @page: Pointer to the allocated pages. 257 * @size: Size of allocated pages. 258 * 259 * This function releases memory allocated by dma_alloc_contiguous(). As the 260 * cma_release returns false when provided pages do not belong to contiguous 261 * area and true otherwise, this function then does a fallback __free_pages() 262 * upon a false-return. 263 */ 264 void dma_free_contiguous(struct device *dev, struct page *page, size_t size) 265 { 266 if (!cma_release(dev_get_cma_area(dev), page, 267 PAGE_ALIGN(size) >> PAGE_SHIFT)) 268 __free_pages(page, get_order(size)); 269 } 270 271 /* 272 * Support for reserved memory regions defined in device tree 273 */ 274 #ifdef CONFIG_OF_RESERVED_MEM 275 #include <linux/of.h> 276 #include <linux/of_fdt.h> 277 #include <linux/of_reserved_mem.h> 278 279 #undef pr_fmt 280 #define pr_fmt(fmt) fmt 281 282 static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev) 283 { 284 dev_set_cma_area(dev, rmem->priv); 285 return 0; 286 } 287 288 static void rmem_cma_device_release(struct reserved_mem *rmem, 289 struct device *dev) 290 { 291 dev_set_cma_area(dev, NULL); 292 } 293 294 static const struct reserved_mem_ops rmem_cma_ops = { 295 .device_init = rmem_cma_device_init, 296 .device_release = rmem_cma_device_release, 297 }; 298 299 static int __init rmem_cma_setup(struct reserved_mem *rmem) 300 { 301 phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order); 302 phys_addr_t mask = align - 1; 303 unsigned long node = rmem->fdt_node; 304 struct cma *cma; 305 int err; 306 307 if (!of_get_flat_dt_prop(node, "reusable", NULL) || 308 of_get_flat_dt_prop(node, "no-map", NULL)) 309 return -EINVAL; 310 311 if ((rmem->base & mask) || (rmem->size & mask)) { 312 pr_err("Reserved memory: incorrect alignment of CMA region\n"); 313 return -EINVAL; 314 } 315 316 err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma); 317 if (err) { 318 pr_err("Reserved memory: unable to setup CMA region\n"); 319 return err; 320 } 321 /* Architecture specific contiguous memory fixup. */ 322 dma_contiguous_early_fixup(rmem->base, rmem->size); 323 324 if (of_get_flat_dt_prop(node, "linux,cma-default", NULL)) 325 dma_contiguous_set_default(cma); 326 327 rmem->ops = &rmem_cma_ops; 328 rmem->priv = cma; 329 330 pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n", 331 &rmem->base, (unsigned long)rmem->size / SZ_1M); 332 333 return 0; 334 } 335 RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup); 336 #endif 337