1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2012 ARM Ltd. 4 * Copyright (c) 2014 The Linux Foundation 5 */ 6 #include <linux/dma-direct.h> 7 #include <linux/dma-noncoherent.h> 8 #include <linux/dma-contiguous.h> 9 #include <linux/init.h> 10 #include <linux/genalloc.h> 11 #include <linux/slab.h> 12 #include <linux/vmalloc.h> 13 14 static struct vm_struct *__dma_common_pages_remap(struct page **pages, 15 size_t size, unsigned long vm_flags, pgprot_t prot, 16 const void *caller) 17 { 18 struct vm_struct *area; 19 20 area = get_vm_area_caller(size, vm_flags, caller); 21 if (!area) 22 return NULL; 23 24 if (map_vm_area(area, prot, pages)) { 25 vunmap(area->addr); 26 return NULL; 27 } 28 29 return area; 30 } 31 32 /* 33 * Remaps an array of PAGE_SIZE pages into another vm_area. 34 * Cannot be used in non-sleeping contexts 35 */ 36 void *dma_common_pages_remap(struct page **pages, size_t size, 37 unsigned long vm_flags, pgprot_t prot, 38 const void *caller) 39 { 40 struct vm_struct *area; 41 42 area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller); 43 if (!area) 44 return NULL; 45 46 area->pages = pages; 47 48 return area->addr; 49 } 50 51 /* 52 * Remaps an allocated contiguous region into another vm_area. 53 * Cannot be used in non-sleeping contexts 54 */ 55 void *dma_common_contiguous_remap(struct page *page, size_t size, 56 unsigned long vm_flags, 57 pgprot_t prot, const void *caller) 58 { 59 int i; 60 struct page **pages; 61 struct vm_struct *area; 62 63 pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL); 64 if (!pages) 65 return NULL; 66 67 for (i = 0; i < (size >> PAGE_SHIFT); i++) 68 pages[i] = nth_page(page, i); 69 70 area = __dma_common_pages_remap(pages, size, vm_flags, prot, caller); 71 72 kfree(pages); 73 74 if (!area) 75 return NULL; 76 return area->addr; 77 } 78 79 /* 80 * Unmaps a range previously mapped by dma_common_*_remap 81 */ 82 void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags) 83 { 84 struct vm_struct *area = find_vm_area(cpu_addr); 85 86 if (!area || (area->flags & vm_flags) != vm_flags) { 87 WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr); 88 return; 89 } 90 91 unmap_kernel_range((unsigned long)cpu_addr, PAGE_ALIGN(size)); 92 vunmap(cpu_addr); 93 } 94 95 #ifdef CONFIG_DMA_DIRECT_REMAP 96 static struct gen_pool *atomic_pool __ro_after_init; 97 98 #define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K 99 static size_t atomic_pool_size __initdata = DEFAULT_DMA_COHERENT_POOL_SIZE; 100 101 static int __init early_coherent_pool(char *p) 102 { 103 atomic_pool_size = memparse(p, &p); 104 return 0; 105 } 106 early_param("coherent_pool", early_coherent_pool); 107 108 int __init dma_atomic_pool_init(gfp_t gfp, pgprot_t prot) 109 { 110 unsigned int pool_size_order = get_order(atomic_pool_size); 111 unsigned long nr_pages = atomic_pool_size >> PAGE_SHIFT; 112 struct page *page; 113 void *addr; 114 int ret; 115 116 if (dev_get_cma_area(NULL)) 117 page = dma_alloc_from_contiguous(NULL, nr_pages, 118 pool_size_order, false); 119 else 120 page = alloc_pages(gfp, pool_size_order); 121 if (!page) 122 goto out; 123 124 arch_dma_prep_coherent(page, atomic_pool_size); 125 126 atomic_pool = gen_pool_create(PAGE_SHIFT, -1); 127 if (!atomic_pool) 128 goto free_page; 129 130 addr = dma_common_contiguous_remap(page, atomic_pool_size, VM_USERMAP, 131 prot, __builtin_return_address(0)); 132 if (!addr) 133 goto destroy_genpool; 134 135 ret = gen_pool_add_virt(atomic_pool, (unsigned long)addr, 136 page_to_phys(page), atomic_pool_size, -1); 137 if (ret) 138 goto remove_mapping; 139 gen_pool_set_algo(atomic_pool, gen_pool_first_fit_order_align, NULL); 140 141 pr_info("DMA: preallocated %zu KiB pool for atomic allocations\n", 142 atomic_pool_size / 1024); 143 return 0; 144 145 remove_mapping: 146 dma_common_free_remap(addr, atomic_pool_size, VM_USERMAP); 147 destroy_genpool: 148 gen_pool_destroy(atomic_pool); 149 atomic_pool = NULL; 150 free_page: 151 if (!dma_release_from_contiguous(NULL, page, nr_pages)) 152 __free_pages(page, pool_size_order); 153 out: 154 pr_err("DMA: failed to allocate %zu KiB pool for atomic coherent allocation\n", 155 atomic_pool_size / 1024); 156 return -ENOMEM; 157 } 158 159 bool dma_in_atomic_pool(void *start, size_t size) 160 { 161 if (unlikely(!atomic_pool)) 162 return false; 163 164 return addr_in_gen_pool(atomic_pool, (unsigned long)start, size); 165 } 166 167 void *dma_alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags) 168 { 169 unsigned long val; 170 void *ptr = NULL; 171 172 if (!atomic_pool) { 173 WARN(1, "coherent pool not initialised!\n"); 174 return NULL; 175 } 176 177 val = gen_pool_alloc(atomic_pool, size); 178 if (val) { 179 phys_addr_t phys = gen_pool_virt_to_phys(atomic_pool, val); 180 181 *ret_page = pfn_to_page(__phys_to_pfn(phys)); 182 ptr = (void *)val; 183 memset(ptr, 0, size); 184 } 185 186 return ptr; 187 } 188 189 bool dma_free_from_pool(void *start, size_t size) 190 { 191 if (!dma_in_atomic_pool(start, size)) 192 return false; 193 gen_pool_free(atomic_pool, (unsigned long)start, size); 194 return true; 195 } 196 197 void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, 198 gfp_t flags, unsigned long attrs) 199 { 200 struct page *page = NULL; 201 void *ret; 202 203 size = PAGE_ALIGN(size); 204 205 if (!gfpflags_allow_blocking(flags)) { 206 ret = dma_alloc_from_pool(size, &page, flags); 207 if (!ret) 208 return NULL; 209 goto done; 210 } 211 212 page = __dma_direct_alloc_pages(dev, size, dma_handle, flags, attrs); 213 if (!page) 214 return NULL; 215 216 /* remove any dirty cache lines on the kernel alias */ 217 arch_dma_prep_coherent(page, size); 218 219 /* create a coherent mapping */ 220 ret = dma_common_contiguous_remap(page, size, VM_USERMAP, 221 arch_dma_mmap_pgprot(dev, PAGE_KERNEL, attrs), 222 __builtin_return_address(0)); 223 if (!ret) { 224 __dma_direct_free_pages(dev, size, page); 225 return ret; 226 } 227 228 memset(ret, 0, size); 229 done: 230 *dma_handle = phys_to_dma(dev, page_to_phys(page)); 231 return ret; 232 } 233 234 void arch_dma_free(struct device *dev, size_t size, void *vaddr, 235 dma_addr_t dma_handle, unsigned long attrs) 236 { 237 if (!dma_free_from_pool(vaddr, PAGE_ALIGN(size))) { 238 phys_addr_t phys = dma_to_phys(dev, dma_handle); 239 struct page *page = pfn_to_page(__phys_to_pfn(phys)); 240 241 vunmap(vaddr); 242 __dma_direct_free_pages(dev, size, page); 243 } 244 } 245 246 long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr, 247 dma_addr_t dma_addr) 248 { 249 return __phys_to_pfn(dma_to_phys(dev, dma_addr)); 250 } 251 #endif /* CONFIG_DMA_DIRECT_REMAP */ 252