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 static struct page *cma_alloc_aligned(struct cma *cma, size_t size, gfp_t gfp) 219 { 220 unsigned int align = min(get_order(size), CONFIG_CMA_ALIGNMENT); 221 222 return cma_alloc(cma, size >> PAGE_SHIFT, align, gfp & __GFP_NOWARN); 223 } 224 225 /** 226 * dma_alloc_contiguous() - allocate contiguous pages 227 * @dev: Pointer to device for which the allocation is performed. 228 * @size: Requested allocation size. 229 * @gfp: Allocation flags. 230 * 231 * This function allocates contiguous memory buffer for specified device. It 232 * tries to use device specific contiguous memory area if available, or the 233 * default global one. 234 * 235 * Note that it byapss one-page size of allocations from the global area as 236 * the addresses within one page are always contiguous, so there is no need 237 * to waste CMA pages for that kind; it also helps reduce fragmentations. 238 */ 239 struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp) 240 { 241 /* CMA can be used only in the context which permits sleeping */ 242 if (!gfpflags_allow_blocking(gfp)) 243 return NULL; 244 if (dev->cma_area) 245 return cma_alloc_aligned(dev->cma_area, size, gfp); 246 if (size <= PAGE_SIZE || !dma_contiguous_default_area) 247 return NULL; 248 return cma_alloc_aligned(dma_contiguous_default_area, size, gfp); 249 } 250 251 /** 252 * dma_free_contiguous() - release allocated pages 253 * @dev: Pointer to device for which the pages were allocated. 254 * @page: Pointer to the allocated pages. 255 * @size: Size of allocated pages. 256 * 257 * This function releases memory allocated by dma_alloc_contiguous(). As the 258 * cma_release returns false when provided pages do not belong to contiguous 259 * area and true otherwise, this function then does a fallback __free_pages() 260 * upon a false-return. 261 */ 262 void dma_free_contiguous(struct device *dev, struct page *page, size_t size) 263 { 264 if (!cma_release(dev_get_cma_area(dev), page, 265 PAGE_ALIGN(size) >> PAGE_SHIFT)) 266 __free_pages(page, get_order(size)); 267 } 268 269 /* 270 * Support for reserved memory regions defined in device tree 271 */ 272 #ifdef CONFIG_OF_RESERVED_MEM 273 #include <linux/of.h> 274 #include <linux/of_fdt.h> 275 #include <linux/of_reserved_mem.h> 276 277 #undef pr_fmt 278 #define pr_fmt(fmt) fmt 279 280 static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev) 281 { 282 dev_set_cma_area(dev, rmem->priv); 283 return 0; 284 } 285 286 static void rmem_cma_device_release(struct reserved_mem *rmem, 287 struct device *dev) 288 { 289 dev_set_cma_area(dev, NULL); 290 } 291 292 static const struct reserved_mem_ops rmem_cma_ops = { 293 .device_init = rmem_cma_device_init, 294 .device_release = rmem_cma_device_release, 295 }; 296 297 static int __init rmem_cma_setup(struct reserved_mem *rmem) 298 { 299 phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order); 300 phys_addr_t mask = align - 1; 301 unsigned long node = rmem->fdt_node; 302 bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL); 303 struct cma *cma; 304 int err; 305 306 if (size_cmdline != -1 && default_cma) { 307 pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n", 308 rmem->name); 309 return -EBUSY; 310 } 311 312 if (!of_get_flat_dt_prop(node, "reusable", NULL) || 313 of_get_flat_dt_prop(node, "no-map", NULL)) 314 return -EINVAL; 315 316 if ((rmem->base & mask) || (rmem->size & mask)) { 317 pr_err("Reserved memory: incorrect alignment of CMA region\n"); 318 return -EINVAL; 319 } 320 321 err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma); 322 if (err) { 323 pr_err("Reserved memory: unable to setup CMA region\n"); 324 return err; 325 } 326 /* Architecture specific contiguous memory fixup. */ 327 dma_contiguous_early_fixup(rmem->base, rmem->size); 328 329 if (default_cma) 330 dma_contiguous_set_default(cma); 331 332 rmem->ops = &rmem_cma_ops; 333 rmem->priv = cma; 334 335 pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n", 336 &rmem->base, (unsigned long)rmem->size / SZ_1M); 337 338 return 0; 339 } 340 RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup); 341 #endif 342