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