drivers/base/dma-contiguous.c

   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