| 1 | |
| 2 | |
| 3 | * Contiguous Memory Allocator for DMA mapping framework
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| 4 | * Copyright (c) 2010-2011 by Samsung Electronics.
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| 5 | * Written by:
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| 6 | * Marek Szyprowski <[email protected]>
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| 7 | * Michal Nazarewicz <[email protected]>
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| 8 | *
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| 9 | * Contiguous Memory Allocator
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| 10 | *
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| 11 | * The Contiguous Memory Allocator (CMA) makes it possible to
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| 12 | * allocate big contiguous chunks of memory after the system has
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| 13 | * booted.
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| 14 | *
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| 15 | * Why is it needed?
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| 16 | *
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| 17 | * Various devices on embedded systems have no scatter-getter and/or
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| 18 | * IO map support and require contiguous blocks of memory to
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| 19 | * operate. They include devices such as cameras, hardware video
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| 20 | * coders, etc.
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| 21 | *
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| 22 | * Such devices often require big memory buffers (a full HD frame
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| 23 | * is, for instance, more than 2 mega pixels large, i.e. more than 6
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| 24 | * MB of memory), which makes mechanisms such as kmalloc() or
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| 25 | * alloc_page() ineffective.
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| 26 | *
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| 27 | * At the same time, a solution where a big memory region is
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| 28 | * reserved for a device is suboptimal since often more memory is
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| 29 | * reserved then strictly required and, moreover, the memory is
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| 30 | * inaccessible to page system even if device drivers don't use it.
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| 31 | *
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| 32 | * CMA tries to solve this issue by operating on memory regions
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| 33 | * where only movable pages can be allocated from. This way, kernel
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| 34 | * can use the memory for pagecache and when device driver requests
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| 35 | * it, allocated pages can be migrated.
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| 36 |
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| 37 |
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| 38 | #define pr_fmt(fmt) "cma: " fmt
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| 39 |
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| 40 | #include <asm/page.h>
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| 41 |
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| 42 | #include <linux/memblock.h>
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| 43 | #include <linux/err.h>
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| 44 | #include <linux/sizes.h>
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| 45 | #include <linux/dma-map-ops.h>
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| 46 | #include <linux/cma.h>
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| 47 | #include <linux/nospec.h>
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| 48 |
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| 49 | #ifdef CONFIG_CMA_SIZE_MBYTES
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| 50 | #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
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| 51 | #else
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| 52 | #define CMA_SIZE_MBYTES 0
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| 53 | #endif
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| 54 |
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| 55 | struct cma *dma_contiguous_default_area;
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| 56 |
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| 57 | |
| 58 | * Default global CMA area size can be defined in kernel's .config.
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| 59 | * This is useful mainly for distro maintainers to create a kernel
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| 60 | * that works correctly for most supported systems.
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| 61 | * The size can be set in bytes or as a percentage of the total memory
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| 62 | * in the system.
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| 63 | *
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| 64 | * Users, who want to set the size of global CMA area for their system
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| 65 | * should use cma= kernel parameter.
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| 66 |
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| 67 | static const phys_addr_t size_bytes __initconst =
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| 68 | (phys_addr_t)CMA_SIZE_MBYTES * SZ_1M;
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| 69 | static phys_addr_t size_cmdline __initdata = -1;
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| 70 | static phys_addr_t base_cmdline __initdata;
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| 71 | static phys_addr_t limit_cmdline __initdata;
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| 72 |
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| 73 | static int __init early_cma(char *p)
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| 74 | {
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| 75 | if (!p) {
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| 76 | pr_err("Config string not provided\n");
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| 77 | return -EINVAL;
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| 78 | }
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| 79 |
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| 80 | size_cmdline = memparse(p, &p);
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| 81 | if (*p != '@')
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| 82 | return 0;
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| 83 | base_cmdline = memparse(p + 1, &p);
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| 84 | if (*p != '-') {
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| 85 | limit_cmdline = base_cmdline + size_cmdline;
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| 86 | return 0;
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| 87 | }
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| 88 | limit_cmdline = memparse(p + 1, &p);
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| 89 |
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| 90 | return 0;
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| 91 | }
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| 92 | early_param("cma", early_cma);
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| 93 |
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| 94 | #ifdef CONFIG_DMA_NUMA_CMA
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| 95 |
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| 96 | static struct cma *dma_contiguous_numa_area[MAX_NUMNODES];
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| 97 | static phys_addr_t numa_cma_size[MAX_NUMNODES] __initdata;
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| 98 | static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES];
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| 99 | static phys_addr_t pernuma_size_bytes __initdata;
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| 100 |
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| 101 | static int __init early_numa_cma(char *p)
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| 102 | {
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| 103 | int nid, count = 0;
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| 104 | unsigned long tmp;
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| 105 | char *s = p;
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| 106 |
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| 107 | while (*s) {
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| 108 | if (sscanf(s, "%lu%n", &tmp, &count) != 1)
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| 109 | break;
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| 110 |
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| 111 | if (s[count] == ':') {
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| 112 | if (tmp >= MAX_NUMNODES)
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| 113 | break;
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| 114 | nid = array_index_nospec(tmp, MAX_NUMNODES);
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| 115 |
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| 116 | s += count + 1;
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| 117 | tmp = memparse(s, &s);
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| 118 | numa_cma_size[nid] = tmp;
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| 119 |
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| 120 | if (*s == ',')
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| 121 | s++;
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| 122 | else
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| 123 | break;
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| 124 | } else
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| 125 | break;
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| 126 | }
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| 127 |
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| 128 | return 0;
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| 129 | }
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| 130 | early_param("numa_cma", early_numa_cma);
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| 131 |
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| 132 | static int __init early_cma_pernuma(char *p)
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| 133 | {
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| 134 | pernuma_size_bytes = memparse(p, &p);
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| 135 | return 0;
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| 136 | }
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| 137 | early_param("cma_pernuma", early_cma_pernuma);
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| 138 | #endif
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| 139 |
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| 140 | #ifdef CONFIG_CMA_SIZE_PERCENTAGE
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| 141 |
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| 142 | static phys_addr_t __init __maybe_unused cma_early_percent_memory(void)
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| 143 | {
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| 144 | unsigned long total_pages = PHYS_PFN(memblock_phys_mem_size());
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| 145 |
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| 146 | return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
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| 147 | }
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| 148 |
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| 149 | #else
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| 150 |
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| 151 | static inline __maybe_unused phys_addr_t cma_early_percent_memory(void)
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| 152 | {
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| 153 | return 0;
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| 154 | }
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| 155 |
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| 156 | #endif
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| 157 |
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| 158 | #ifdef CONFIG_DMA_NUMA_CMA
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| 159 | static void __init dma_numa_cma_reserve(void)
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| 160 | {
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| 161 | int nid;
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| 162 |
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| 163 | for_each_node(nid) {
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| 164 | int ret;
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| 165 | char name[CMA_MAX_NAME];
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| 166 | struct cma **cma;
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| 167 |
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| 168 | if (!node_online(nid)) {
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| 169 | if (pernuma_size_bytes || numa_cma_size[nid])
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| 170 | pr_warn("invalid node %d specified\n", nid);
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| 171 | continue;
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| 172 | }
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| 173 |
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| 174 | if (pernuma_size_bytes) {
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| 175 |
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| 176 | cma = &dma_contiguous_pernuma_area[nid];
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| 177 | snprintf(name, sizeof(name), "pernuma%d", nid);
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| 178 | ret = cma_declare_contiguous_nid(0, pernuma_size_bytes, 0, 0,
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| 179 | 0, false, name, cma, nid);
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| 180 | if (ret)
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| 181 | pr_warn("%s: reservation failed: err %d, node %d", __func__,
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| 182 | ret, nid);
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| 183 | }
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| 184 |
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| 185 | if (numa_cma_size[nid]) {
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| 186 |
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| 187 | cma = &dma_contiguous_numa_area[nid];
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| 188 | snprintf(name, sizeof(name), "numa%d", nid);
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| 189 | ret = cma_declare_contiguous_nid(0, numa_cma_size[nid], 0, 0, 0, false,
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| 190 | name, cma, nid);
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| 191 | if (ret)
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| 192 | pr_warn("%s: reservation failed: err %d, node %d", __func__,
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| 193 | ret, nid);
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| 194 | }
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| 195 | }
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| 196 | }
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| 197 | #else
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| 198 | static inline void __init dma_numa_cma_reserve(void)
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| 199 | {
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| 200 | }
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| 201 | #endif
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| 202 |
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| 203 | |
| 204 | * dma_contiguous_reserve() - reserve area(s) for contiguous memory handling
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| 205 | * @limit: End address of the reserved memory (optional, 0 for any).
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| 206 | *
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| 207 | * This function reserves memory from early allocator. It should be
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| 208 | * called by arch specific code once the early allocator (memblock or bootmem)
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| 209 | * has been activated and all other subsystems have already allocated/reserved
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| 210 | * memory.
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| 211 |
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| 212 | void __init dma_contiguous_reserve(phys_addr_t limit)
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| 213 | {
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| 214 | phys_addr_t selected_size = 0;
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| 215 | phys_addr_t selected_base = 0;
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| 216 | phys_addr_t selected_limit = limit;
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| 217 | bool fixed = false;
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| 218 |
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| 219 | dma_numa_cma_reserve();
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| 220 |
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| 221 | pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
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| 222 |
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| 223 | if (size_cmdline != -1) {
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| 224 | selected_size = size_cmdline;
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| 225 | selected_base = base_cmdline;
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| 226 | selected_limit = min_not_zero(limit_cmdline, limit);
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| 227 | if (base_cmdline + size_cmdline == limit_cmdline)
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| 228 | fixed = true;
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| 229 | } else {
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| 230 | #ifdef CONFIG_CMA_SIZE_SEL_MBYTES
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| 231 | selected_size = size_bytes;
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| 232 | #elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
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| 233 | selected_size = cma_early_percent_memory();
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| 234 | #elif defined(CONFIG_CMA_SIZE_SEL_MIN)
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| 235 | selected_size = min(size_bytes, cma_early_percent_memory());
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| 236 | #elif defined(CONFIG_CMA_SIZE_SEL_MAX)
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| 237 | selected_size = max(size_bytes, cma_early_percent_memory());
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| 238 | #endif
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| 239 | }
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| 240 |
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| 241 | if (selected_size && !dma_contiguous_default_area) {
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| 242 | pr_debug("%s: reserving %ld MiB for global area\n", __func__,
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| 243 | (unsigned long)selected_size / SZ_1M);
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| 244 |
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| 245 | dma_contiguous_reserve_area(selected_size, selected_base,
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| 246 | selected_limit,
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| 247 | &dma_contiguous_default_area,
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| 248 | fixed);
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| 249 | }
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| 250 | }
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| 251 |
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| 252 | void __weak
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| 253 | dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
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| 254 | {
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| 255 | }
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| 256 |
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| 257 | |
| 258 | * dma_contiguous_reserve_area() - reserve custom contiguous area
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| 259 | * @size: Size of the reserved area (in bytes),
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| 260 | * @base: Base address of the reserved area optional, use 0 for any
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| 261 | * @limit: End address of the reserved memory (optional, 0 for any).
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| 262 | * @res_cma: Pointer to store the created cma region.
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| 263 | * @fixed: hint about where to place the reserved area
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| 264 | *
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| 265 | * This function reserves memory from early allocator. It should be
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| 266 | * called by arch specific code once the early allocator (memblock or bootmem)
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| 267 | * has been activated and all other subsystems have already allocated/reserved
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| 268 | * memory. This function allows to create custom reserved areas for specific
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| 269 | * devices.
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| 270 | *
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| 271 | * If @fixed is true, reserve contiguous area at exactly @base. If false,
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| 272 | * reserve in range from @base to @limit.
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| 273 |
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| 274 | int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
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| 275 | phys_addr_t limit, struct cma **res_cma,
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| 276 | bool fixed)
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| 277 | {
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| 278 | int ret;
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| 279 |
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| 280 | ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed,
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| 281 | "reserved", res_cma);
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| 282 | if (ret)
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| 283 | return ret;
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| 284 |
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| 285 |
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| 286 | dma_contiguous_early_fixup(cma_get_base(*res_cma),
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| 287 | cma_get_size(*res_cma));
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| 288 |
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| 289 | return 0;
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| 290 | }
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| 291 |
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| 292 | |
| 293 | * dma_alloc_from_contiguous() - allocate pages from contiguous area
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| 294 | * @dev: Pointer to device for which the allocation is performed.
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| 295 | * @count: Requested number of pages.
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| 296 | * @align: Requested alignment of pages (in PAGE_SIZE order).
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| 297 | * @no_warn: Avoid printing message about failed allocation.
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| 298 | *
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| 299 | * This function allocates memory buffer for specified device. It uses
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| 300 | * device specific contiguous memory area if available or the default
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| 301 | * global one. Requires architecture specific dev_get_cma_area() helper
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| 302 | * function.
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| 303 |
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| 304 | struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
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| 305 | unsigned int align, bool no_warn)
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| 306 | {
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| 307 | if (align > CONFIG_CMA_ALIGNMENT)
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| 308 | align = CONFIG_CMA_ALIGNMENT;
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| 309 |
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| 310 | return cma_alloc(dev_get_cma_area(dev), count, align, no_warn);
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| 311 | }
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| 312 |
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| 313 | |
| 314 | * dma_release_from_contiguous() - release allocated pages
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| 315 | * @dev: Pointer to device for which the pages were allocated.
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| 316 | * @pages: Allocated pages.
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| 317 | * @count: Number of allocated pages.
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| 318 | *
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| 319 | * This function releases memory allocated by dma_alloc_from_contiguous().
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| 320 | * It returns false when provided pages do not belong to contiguous area and
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| 321 | * true otherwise.
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| 322 |
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| 323 | bool dma_release_from_contiguous(struct device *dev, struct page *pages,
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| 324 | int count)
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| 325 | {
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| 326 | return cma_release(dev_get_cma_area(dev), pages, count);
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| 327 | }
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| 328 |
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| 329 | static struct page *cma_alloc_aligned(struct cma *cma, size_t size, gfp_t gfp)
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| 330 | {
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| 331 | unsigned int align = min(get_order(size), CONFIG_CMA_ALIGNMENT);
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| 332 |
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| 333 | return cma_alloc(cma, size >> PAGE_SHIFT, align, gfp & __GFP_NOWARN);
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| 334 | }
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| 335 |
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| 336 | |
| 337 | * dma_alloc_contiguous() - allocate contiguous pages
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| 338 | * @dev: Pointer to device for which the allocation is performed.
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| 339 | * @size: Requested allocation size.
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| 340 | * @gfp: Allocation flags.
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| 341 | *
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| 342 | * tries to use device specific contiguous memory area if available, or it
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| 343 | * tries to use per-numa cma, if the allocation fails, it will fallback to
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| 344 | * try default global one.
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| 345 | *
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| 346 | * Note that it bypass one-page size of allocations from the per-numa and
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| 347 | * global area as the addresses within one page are always contiguous, so
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| 348 | * there is no need to waste CMA pages for that kind; it also helps reduce
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| 349 | * fragmentations.
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| 350 |
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| 351 | struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
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| 352 | {
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| 353 | #ifdef CONFIG_DMA_NUMA_CMA
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| 354 | int nid = dev_to_node(dev);
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| 355 | #endif
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| 356 |
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| 357 |
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| 358 | if (!gfpflags_allow_blocking(gfp))
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| 359 | return NULL;
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| 360 | if (dev->cma_area)
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| 361 | return cma_alloc_aligned(dev->cma_area, size, gfp);
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| 362 | if (size <= PAGE_SIZE)
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| 363 | return NULL;
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| 364 |
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| 365 | #ifdef CONFIG_DMA_NUMA_CMA
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| 366 | if (nid != NUMA_NO_NODE && !(gfp & (GFP_DMA | GFP_DMA32))) {
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| 367 | struct cma *cma = dma_contiguous_pernuma_area[nid];
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| 368 | struct page *page;
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| 369 |
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| 370 | if (cma) {
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| 371 | page = cma_alloc_aligned(cma, size, gfp);
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| 372 | if (page)
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| 373 | return page;
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| 374 | }
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| 375 |
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| 376 | cma = dma_contiguous_numa_area[nid];
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| 377 | if (cma) {
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| 378 | page = cma_alloc_aligned(cma, size, gfp);
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| 379 | if (page)
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| 380 | return page;
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| 381 | }
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| 382 | }
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| 383 | #endif
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| 384 | if (!dma_contiguous_default_area)
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| 385 | return NULL;
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| 386 |
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| 387 | return cma_alloc_aligned(dma_contiguous_default_area, size, gfp);
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| 388 | }
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| 389 |
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| 390 | |
| 391 | * dma_free_contiguous() - release allocated pages
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| 392 | * @dev: Pointer to device for which the pages were allocated.
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| 393 | * @page: Pointer to the allocated pages.
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| 394 | * @size: Size of allocated pages.
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| 395 | *
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| 396 | * This function releases memory allocated by dma_alloc_contiguous(). As the
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| 397 | * cma_release returns false when provided pages do not belong to contiguous
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| 398 | * area and true otherwise, this function then does a fallback __free_pages()
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| 399 | * upon a false-return.
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| 400 |
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| 401 | void dma_free_contiguous(struct device *dev, struct page *page, size_t size)
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| 402 | {
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| 403 | unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
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| 404 |
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| 405 |
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| 406 | if (dev->cma_area) {
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| 407 | if (cma_release(dev->cma_area, page, count))
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| 408 | return;
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| 409 | } else {
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| 410 | |
| 411 | * otherwise, page is from either per-numa cma or default cma
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| 412 |
|
| 413 | #ifdef CONFIG_DMA_NUMA_CMA
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| 414 | if (cma_release(dma_contiguous_pernuma_area[page_to_nid(page)],
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| 415 | page, count))
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| 416 | return;
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| 417 | if (cma_release(dma_contiguous_numa_area[page_to_nid(page)],
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| 418 | page, count))
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| 419 | return;
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| 420 | #endif
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| 421 | if (cma_release(dma_contiguous_default_area, page, count))
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| 422 | return;
|
| 423 | }
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| 424 |
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| 425 |
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| 426 | __free_pages(page, get_order(size));
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| 427 | }
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| 428 |
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| 429 | |
| 430 | * Support for reserved memory regions defined in device tree
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| 431 |
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| 432 | #ifdef CONFIG_OF_RESERVED_MEM
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| 433 | #include <linux/of.h>
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| 434 | #include <linux/of_fdt.h>
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| 435 | #include <linux/of_reserved_mem.h>
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| 436 |
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| 437 | #undef pr_fmt
|
| 438 | #define pr_fmt(fmt) fmt
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| 439 |
|
| 440 | static int rmem_cma_device_init(struct reserved_mem *rmem, struct device *dev)
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| 441 | {
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| 442 | dev->cma_area = rmem->priv;
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| 443 | return 0;
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| 444 | }
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| 445 |
|
| 446 | static void rmem_cma_device_release(struct reserved_mem *rmem,
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| 447 | struct device *dev)
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| 448 | {
|
| 449 | dev->cma_area = NULL;
|
| 450 | }
|
| 451 |
|
| 452 | static const struct reserved_mem_ops rmem_cma_ops = {
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| 453 | .device_init = rmem_cma_device_init,
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| 454 | .device_release = rmem_cma_device_release,
|
| 455 | };
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| 456 |
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| 457 | static int __init rmem_cma_setup(struct reserved_mem *rmem)
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| 458 | {
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| 459 | unsigned long node = rmem->fdt_node;
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| 460 | bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
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| 461 | struct cma *cma;
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| 462 | int err;
|
| 463 |
|
| 464 | if (size_cmdline != -1 && default_cma) {
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| 465 | pr_info("Reserved memory: bypass %s node, using cmdline CMA params instead\n",
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| 466 | rmem->name);
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| 467 | return -EBUSY;
|
| 468 | }
|
| 469 |
|
| 470 | if (!of_get_flat_dt_prop(node, "reusable", NULL) ||
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| 471 | of_get_flat_dt_prop(node, "no-map", NULL))
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| 472 | return -EINVAL;
|
| 473 |
|
| 474 | if (!IS_ALIGNED(rmem->base | rmem->size, CMA_MIN_ALIGNMENT_BYTES)) {
|
| 475 | pr_err("Reserved memory: incorrect alignment of CMA region\n");
|
| 476 | return -EINVAL;
|
| 477 | }
|
| 478 |
|
| 479 | err = cma_init_reserved_mem(rmem->base, rmem->size, 0, rmem->name, &cma);
|
| 480 | if (err) {
|
| 481 | pr_err("Reserved memory: unable to setup CMA region\n");
|
| 482 | return err;
|
| 483 | }
|
| 484 |
|
| 485 | dma_contiguous_early_fixup(rmem->base, rmem->size);
|
| 486 |
|
| 487 | if (default_cma)
|
| 488 | dma_contiguous_default_area = cma;
|
| 489 |
|
| 490 | rmem->ops = &rmem_cma_ops;
|
| 491 | rmem->priv = cma;
|
| 492 |
|
| 493 | pr_info("Reserved memory: created CMA memory pool at %pa, size %ld MiB\n",
|
| 494 | &rmem->base, (unsigned long)rmem->size / SZ_1M);
|
| 495 |
|
| 496 | return 0;
|
| 497 | }
|
| 498 | RESERVEDMEM_OF_DECLARE(cma, "shared-dma-pool", rmem_cma_setup);
|
| 499 | #endif
|