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/mm.h>
  28 #include <linux/mutex.h>
  29 #include <linux/page-isolation.h>
  30 #include <linux/sizes.h>
  31 #include <linux/slab.h>
  32 #include <linux/swap.h>
  33 #include <linux/mm_types.h>
  34 #include <linux/dma-contiguous.h>
  35
  36 struct cma {
  37         unsigned long   base_pfn;
  38         unsigned long   count;
  39         unsigned long   *bitmap;
  40 };
  41
  42 struct cma *dma_contiguous_default_area;
  43
  44 #ifdef CONFIG_CMA_SIZE_MBYTES
  45 #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
  46 #else
  47 #define CMA_SIZE_MBYTES 0
  48 #endif
  49
  50 /*
  51  * Default global CMA area size can be defined in kernel's .config.
  52  * This is usefull mainly for distro maintainers to create a kernel
  53  * that works correctly for most supported systems.
  54  * The size can be set in bytes or as a percentage of the total memory
  55  * in the system.
  56  *
  57  * Users, who want to set the size of global CMA area for their system
  58  * should use cma= kernel parameter.
  59  */
  60 static const phys_addr_t size_bytes = CMA_SIZE_MBYTES * SZ_1M;
  61 static phys_addr_t size_cmdline = -1;
  62
  63 static int __init early_cma(char *p)
  64 {
  65         pr_debug("%s(%s)\n", __func__, p);
  66         size_cmdline = memparse(p, &p);
  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 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
 111         pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
 112
 113         if (size_cmdline != -1) {
 114                 selected_size = size_cmdline;
 115         } else {
 116 #ifdef CONFIG_CMA_SIZE_SEL_MBYTES
 117                 selected_size = size_bytes;
 118 #elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
 119                 selected_size = cma_early_percent_memory();
 120 #elif defined(CONFIG_CMA_SIZE_SEL_MIN)
 121                 selected_size = min(size_bytes, cma_early_percent_memory());
 122 #elif defined(CONFIG_CMA_SIZE_SEL_MAX)
 123                 selected_size = max(size_bytes, cma_early_percent_memory());
 124 #endif
 125         }
 126
 127         if (selected_size) {
 128                 pr_debug("%s: reserving %ld MiB for global area\n", __func__,
 129                          (unsigned long)selected_size / SZ_1M);
 130
 131                 dma_declare_contiguous(NULL, selected_size, 0, limit);
 132         }
 133 };
 134
 135 static DEFINE_MUTEX(cma_mutex);
 136
 137 static __init int cma_activate_area(unsigned long base_pfn, unsigned long count)
 138 {
 139         unsigned long pfn = base_pfn;
 140         unsigned i = count >> pageblock_order;
 141         struct zone *zone;
 142
 143         WARN_ON_ONCE(!pfn_valid(pfn));
 144         zone = page_zone(pfn_to_page(pfn));
 145
 146         do {
 147                 unsigned j;
 148                 base_pfn = pfn;
 149                 for (j = pageblock_nr_pages; j; --j, pfn++) {
 150                         WARN_ON_ONCE(!pfn_valid(pfn));
 151                         if (page_zone(pfn_to_page(pfn)) != zone)
 152                                 return -EINVAL;
 153                 }
 154                 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
 155         } while (--i);
 156         return 0;
 157 }
 158
 159 static __init struct cma *cma_create_area(unsigned long base_pfn,
 160                                      unsigned long count)
 161 {
 162         int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
 163         struct cma *cma;
 164         int ret = -ENOMEM;
 165
 166         pr_debug("%s(base %08lx, count %lx)\n", __func__, base_pfn, count);
 167
 168         cma = kmalloc(sizeof *cma, GFP_KERNEL);
 169         if (!cma)
 170                 return ERR_PTR(-ENOMEM);
 171
 172         cma->base_pfn = base_pfn;
 173         cma->count = count;
 174         cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
 175
 176         if (!cma->bitmap)
 177                 goto no_mem;
 178
 179         ret = cma_activate_area(base_pfn, count);
 180         if (ret)
 181                 goto error;
 182
 183         pr_debug("%s: returned %p\n", __func__, (void *)cma);
 184         return cma;
 185
 186 error:
 187         kfree(cma->bitmap);
 188 no_mem:
 189         kfree(cma);
 190         return ERR_PTR(ret);
 191 }
 192
 193 static struct cma_reserved {
 194         phys_addr_t start;
 195         unsigned long size;
 196         struct device *dev;
 197 } cma_reserved[MAX_CMA_AREAS] __initdata;
 198 static unsigned cma_reserved_count __initdata;
 199
 200 static int __init cma_init_reserved_areas(void)
 201 {
 202         struct cma_reserved *r = cma_reserved;
 203         unsigned i = cma_reserved_count;
 204
 205         pr_debug("%s()\n", __func__);
 206
 207         for (; i; --i, ++r) {
 208                 struct cma *cma;
 209                 cma = cma_create_area(PFN_DOWN(r->start),
 210                                       r->size >> PAGE_SHIFT);
 211                 if (!IS_ERR(cma))
 212                         dev_set_cma_area(r->dev, cma);
 213         }
 214         return 0;
 215 }
 216 core_initcall(cma_init_reserved_areas);
 217
 218 /**
 219  * dma_declare_contiguous() - reserve area for contiguous memory handling
 220  *                            for particular device
 221  * @dev:   Pointer to device structure.
 222  * @size:  Size of the reserved memory.
 223  * @base:  Start address of the reserved memory (optional, 0 for any).
 224  * @limit: End address of the reserved memory (optional, 0 for any).
 225  *
 226  * This function reserves memory for specified device. It should be
 227  * called by board specific code when early allocator (memblock or bootmem)
 228  * is still activate.
 229  */
 230 int __init dma_declare_contiguous(struct device *dev, phys_addr_t size,
 231                                   phys_addr_t base, phys_addr_t limit)
 232 {
 233         struct cma_reserved *r = &cma_reserved[cma_reserved_count];
 234         phys_addr_t alignment;
 235
 236         pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
 237                  (unsigned long)size, (unsigned long)base,
 238                  (unsigned long)limit);
 239
 240         /* Sanity checks */
 241         if (cma_reserved_count == ARRAY_SIZE(cma_reserved)) {
 242                 pr_err("Not enough slots for CMA reserved regions!\n");
 243                 return -ENOSPC;
 244         }
 245
 246         if (!size)
 247                 return -EINVAL;
 248
 249         /* Sanitise input arguments */
 250         alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
 251         base = ALIGN(base, alignment);
 252         size = ALIGN(size, alignment);
 253         limit &= ~(alignment - 1);
 254
 255         /* Reserve memory */
 256         if (base) {
 257                 if (memblock_is_region_reserved(base, size) ||
 258                     memblock_reserve(base, size) < 0) {
 259                         base = -EBUSY;
 260                         goto err;
 261                 }
 262         } else {
 263                 /*
 264                  * Use __memblock_alloc_base() since
 265                  * memblock_alloc_base() panic()s.
 266                  */
 267                 phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
 268                 if (!addr) {
 269                         base = -ENOMEM;
 270                         goto err;
 271                 } else {
 272                         base = addr;
 273                 }
 274         }
 275
 276         /*
 277          * Each reserved area must be initialised later, when more kernel
 278          * subsystems (like slab allocator) are available.
 279          */
 280         r->start = base;
 281         r->size = size;
 282         r->dev = dev;
 283         cma_reserved_count++;
 284         pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
 285                 (unsigned long)base);
 286
 287         /* Architecture specific contiguous memory fixup. */
 288         dma_contiguous_early_fixup(base, size);
 289         return 0;
 290 err:
 291         pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 292         return base;
 293 }
 294
 295 /**
 296  * dma_alloc_from_contiguous() - allocate pages from contiguous area
 297  * @dev:   Pointer to device for which the allocation is performed.
 298  * @count: Requested number of pages.
 299  * @align: Requested alignment of pages (in PAGE_SIZE order).
 300  *
 301  * This function allocates memory buffer for specified device. It uses
 302  * device specific contiguous memory area if available or the default
 303  * global one. Requires architecture specific get_dev_cma_area() helper
 304  * function.
 305  */
 306 struct page *dma_alloc_from_contiguous(struct device *dev, int count,
 307                                        unsigned int align)
 308 {
 309         unsigned long mask, pfn, pageno, start = 0;
 310         struct cma *cma = dev_get_cma_area(dev);
 311         struct page *page = NULL;
 312         int ret;
 313
 314         if (!cma || !cma->count)
 315                 return NULL;
 316
 317         if (align > CONFIG_CMA_ALIGNMENT)
 318                 align = CONFIG_CMA_ALIGNMENT;
 319
 320         pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
 321                  count, align);
 322
 323         if (!count)
 324                 return NULL;
 325
 326         mask = (1 << align) - 1;
 327
 328         mutex_lock(&cma_mutex);
 329
 330         for (;;) {
 331                 pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
 332                                                     start, count, mask);
 333                 if (pageno >= cma->count)
 334                         break;
 335
 336                 pfn = cma->base_pfn + pageno;
 337                 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
 338                 if (ret == 0) {
 339                         bitmap_set(cma->bitmap, pageno, count);
 340                         page = pfn_to_page(pfn);
 341                         break;
 342                 } else if (ret != -EBUSY) {
 343                         break;
 344                 }
 345                 pr_debug("%s(): memory range at %p is busy, retrying\n",
 346                          __func__, pfn_to_page(pfn));
 347                 /* try again with a bit different memory target */
 348                 start = pageno + mask + 1;
 349         }
 350
 351         mutex_unlock(&cma_mutex);
 352         pr_debug("%s(): returned %p\n", __func__, page);
 353         return page;
 354 }
 355
 356 /**
 357  * dma_release_from_contiguous() - release allocated pages
 358  * @dev:   Pointer to device for which the pages were allocated.
 359  * @pages: Allocated pages.
 360  * @count: Number of allocated pages.
 361  *
 362  * This function releases memory allocated by dma_alloc_from_contiguous().
 363  * It returns false when provided pages do not belong to contiguous area and
 364  * true otherwise.
 365  */
 366 bool dma_release_from_contiguous(struct device *dev, struct page *pages,
 367                                  int count)
 368 {
 369         struct cma *cma = dev_get_cma_area(dev);
 370         unsigned long pfn;
 371
 372         if (!cma || !pages)
 373                 return false;
 374
 375         pr_debug("%s(page %p)\n", __func__, (void *)pages);
 376
 377         pfn = page_to_pfn(pages);
 378
 379         if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
 380                 return false;
 381
 382         VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
 383
 384         mutex_lock(&cma_mutex);
 385         bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
 386         free_contig_range(pfn, count);
 387         mutex_unlock(&cma_mutex);
 388
 389         return true;
 390 }