drivers/base/dma-contiguous.c

   1 /*
   2  * Contiguous Memory Allocator for DMA mapping framework
   3  * Copyright (c) 2010-2011 by Samsung Electronics.
   4  * Written by:
   5  *      Marek Szyprowski <m.szyprowski@samsung.com>
   6  *      Michal Nazarewicz <mina86@mina86.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of the
  11  * License or (at your optional) any later version of the license.
  12  */
  13
  14 #define pr_fmt(fmt) "cma: " fmt
  15
  16 #ifdef CONFIG_CMA_DEBUG
  17 #ifndef DEBUG
  18 #  define DEBUG
  19 #endif
  20 #endif
  21
  22 #include <asm/page.h>
  23 #include <asm/dma-contiguous.h>
  24
  25 #include <linux/memblock.h>
  26 #include <linux/err.h>
  27 #include <linux/sizes.h>
  28 #include <linux/dma-contiguous.h>
  29 #include <linux/cma.h>
  30
  31 #ifdef CONFIG_CMA_SIZE_MBYTES
  32 #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
  33 #else
  34 #define CMA_SIZE_MBYTES 0
  35 #endif
  36
  37 struct cma *dma_contiguous_default_area;
  38
  39 /*
  40  * Default global CMA area size can be defined in kernel's .config.
  41  * This is useful mainly for distro maintainers to create a kernel
  42  * that works correctly for most supported systems.
  43  * The size can be set in bytes or as a percentage of the total memory
  44  * in the system.
  45  *
  46  * Users, who want to set the size of global CMA area for their system
  47  * should use cma= kernel parameter.
  48  */
  49 static const phys_addr_t size_bytes = (phys_addr_t)CMA_SIZE_MBYTES * SZ_1M;
  50 static phys_addr_t size_cmdline = -1;
  51 static phys_addr_t base_cmdline;
  52 static phys_addr_t limit_cmdline;
  53
  54 static int __init early_cma(char *p)
  55 {
  56         pr_debug("%s(%s)\n", __func__, p);
  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, res_cma);
 169         if (ret)
 170                 return ret;
 171
 172         /* Architecture specific contiguous memory fixup. */
 173         dma_contiguous_early_fixup(cma_get_base(*res_cma),
 174                                 cma_get_size(*res_cma));
 175
 176         return 0;
 177 }
 178
 179 /**
 180  * dma_alloc_from_contiguous() - allocate pages from contiguous area
 181  * @dev:   Pointer to device for which the allocation is performed.
 182  * @count: Requested number of pages.
 183  * @align: Requested alignment of pages (in PAGE_SIZE order).
 184  *
 185  * This function allocates memory buffer for specified device. It uses
 186  * device specific contiguous memory area if available or the default
 187  * global one. Requires architecture specific dev_get_cma_area() helper
 188  * function.
 189  */
 190 struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
 191                                        unsigned int align)
 192 {
 193         if (align > CONFIG_CMA_ALIGNMENT)
 194                 align = CONFIG_CMA_ALIGNMENT;
 195
 196         return cma_alloc(dev_get_cma_area(dev), count, align);
 197 }
 198
 199 /**
 200  * dma_release_from_contiguous() - release allocated pages
 201  * @dev:   Pointer to device for which the pages were allocated.
 202  * @pages: Allocated pages.
 203  * @count: Number of allocated pages.
 204  *
 205  * This function releases memory allocated by dma_alloc_from_contiguous().
 206  * It returns false when provided pages do not belong to contiguous area and
 207  * true otherwise.
 208  */
 209 bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 210                                  int count)
 211 {
 212         return cma_release(dev_get_cma_area(dev), pages, count);
 213 }
 214
 215 /*
 216  * Support for reserved memory regions defined in device tree
 217  */
 218 #ifdef CONFIG_OF_RESERVED_MEM
 219 #include <linux/of.h>
 220 #include <linux/of_fdt.h>
 221 #include <linux/of_reserved_mem.h>
 222
 223 #undef pr_fmt
 224 #define pr_fmt(fmt) fmt
 225
 226 static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev)
 227 {
 228         dev_set_cma_area(dev, rmem->priv);
 229         return 0;
 230 }
 231
 232 static void rmem_cma_device_release(struct reserved_mem *rmem,
 233                                     struct device *dev)
 234 {
 235         dev_set_cma_area(dev, NULL);
 236 }
 237
 238 static const struct reserved_mem_ops rmem_cma_ops = {
 239         .device_init    = rmem_cma_device_init,
 240         .device_release = rmem_cma_device_release,
 241 };
 242
 243 static int __init rmem_cma_setup(struct reserved_mem *rmem)
 244 {
 245         phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
 246         phys_addr_t mask = align - 1;
 247         unsigned long node = rmem->fdt_node;
 248         struct cma *cma;
 249         int err;
 250
 251         if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
 252             of_get_flat_dt_prop(node, "no-map", NULL))
 253                 return -EINVAL;
 254
 255         if ((rmem->base & mask) || (rmem->size & mask)) {
 256                 pr_err("Reserved memory: incorrect alignment of CMA region\n");
 257                 return -EINVAL;
 258         }
 259
 260         err = cma_init_reserved_mem(rmem->base, rmem->size, 0, &cma);
 261         if (err) {
 262                 pr_err("Reserved memory: unable to setup CMA region\n");
 263                 return err;
 264         }
 265         /* Architecture specific contiguous memory fixup. */
 266         dma_contiguous_early_fixup(rmem->base, rmem->size);
 267
 268         if (of_get_flat_dt_prop(node, "linux,cma-default", NULL))
 269                 dma_contiguous_set_default(cma);
 270
 271         rmem->ops = &rmem_cma_ops;
 272         rmem->priv = cma;
 273
 274         pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
 275                 &rmem->base, (unsigned long)rmem->size / SZ_1M);
 276
 277         return 0;
 278 }
 279 RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
 280 #endif