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