1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #include <linux/device.h> 3 #include <linux/types.h> 4 #include <linux/io.h> 5 #include <linux/mm.h> 6 7 #ifndef ioremap_cache 8 /* temporary while we convert existing ioremap_cache users to memremap */ 9 __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size) 10 { 11 return ioremap(offset, size); 12 } 13 #endif 14 15 #ifndef arch_memremap_wb 16 static void *arch_memremap_wb(resource_size_t offset, unsigned long size) 17 { 18 return (__force void *)ioremap_cache(offset, size); 19 } 20 #endif 21 22 #ifndef arch_memremap_can_ram_remap 23 static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size, 24 unsigned long flags) 25 { 26 return true; 27 } 28 #endif 29 30 static void *try_ram_remap(resource_size_t offset, size_t size, 31 unsigned long flags) 32 { 33 unsigned long pfn = PHYS_PFN(offset); 34 35 /* In the simple case just return the existing linear address */ 36 if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) && 37 arch_memremap_can_ram_remap(offset, size, flags)) 38 return __va(offset); 39 40 return NULL; /* fallback to arch_memremap_wb */ 41 } 42 43 /** 44 * memremap() - remap an iomem_resource as cacheable memory 45 * @offset: iomem resource start address 46 * @size: size of remap 47 * @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC, 48 * MEMREMAP_ENC, MEMREMAP_DEC 49 * 50 * memremap() is "ioremap" for cases where it is known that the resource 51 * being mapped does not have i/o side effects and the __iomem 52 * annotation is not applicable. In the case of multiple flags, the different 53 * mapping types will be attempted in the order listed below until one of 54 * them succeeds. 55 * 56 * MEMREMAP_WB - matches the default mapping for System RAM on 57 * the architecture. This is usually a read-allocate write-back cache. 58 * Moreover, if MEMREMAP_WB is specified and the requested remap region is RAM 59 * memremap() will bypass establishing a new mapping and instead return 60 * a pointer into the direct map. 61 * 62 * MEMREMAP_WT - establish a mapping whereby writes either bypass the 63 * cache or are written through to memory and never exist in a 64 * cache-dirty state with respect to program visibility. Attempts to 65 * map System RAM with this mapping type will fail. 66 * 67 * MEMREMAP_WC - establish a writecombine mapping, whereby writes may 68 * be coalesced together (e.g. in the CPU's write buffers), but is otherwise 69 * uncached. Attempts to map System RAM with this mapping type will fail. 70 */ 71 void *memremap(resource_size_t offset, size_t size, unsigned long flags) 72 { 73 int is_ram = region_intersects(offset, size, 74 IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); 75 void *addr = NULL; 76 77 if (!flags) 78 return NULL; 79 80 if (is_ram == REGION_MIXED) { 81 WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n", 82 &offset, (unsigned long) size); 83 return NULL; 84 } 85 86 /* Try all mapping types requested until one returns non-NULL */ 87 if (flags & MEMREMAP_WB) { 88 /* 89 * MEMREMAP_WB is special in that it can be satisfied 90 * from the direct map. Some archs depend on the 91 * capability of memremap() to autodetect cases where 92 * the requested range is potentially in System RAM. 93 */ 94 if (is_ram == REGION_INTERSECTS) 95 addr = try_ram_remap(offset, size, flags); 96 if (!addr) 97 addr = arch_memremap_wb(offset, size); 98 } 99 100 /* 101 * If we don't have a mapping yet and other request flags are 102 * present then we will be attempting to establish a new virtual 103 * address mapping. Enforce that this mapping is not aliasing 104 * System RAM. 105 */ 106 if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) { 107 WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n", 108 &offset, (unsigned long) size); 109 return NULL; 110 } 111 112 if (!addr && (flags & MEMREMAP_WT)) 113 addr = ioremap_wt(offset, size); 114 115 if (!addr && (flags & MEMREMAP_WC)) 116 addr = ioremap_wc(offset, size); 117 118 return addr; 119 } 120 EXPORT_SYMBOL(memremap); 121 122 void memunmap(void *addr) 123 { 124 if (is_ioremap_addr(addr)) 125 iounmap((void __iomem *) addr); 126 } 127 EXPORT_SYMBOL(memunmap); 128 129 static void devm_memremap_release(struct device *dev, void *res) 130 { 131 memunmap(*(void **)res); 132 } 133 134 static int devm_memremap_match(struct device *dev, void *res, void *match_data) 135 { 136 return *(void **)res == match_data; 137 } 138 139 void *devm_memremap(struct device *dev, resource_size_t offset, 140 size_t size, unsigned long flags) 141 { 142 void **ptr, *addr; 143 144 ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL, 145 dev_to_node(dev)); 146 if (!ptr) 147 return ERR_PTR(-ENOMEM); 148 149 addr = memremap(offset, size, flags); 150 if (addr) { 151 *ptr = addr; 152 devres_add(dev, ptr); 153 } else { 154 devres_free(ptr); 155 return ERR_PTR(-ENXIO); 156 } 157 158 return addr; 159 } 160 EXPORT_SYMBOL(devm_memremap); 161 162 void devm_memunmap(struct device *dev, void *addr) 163 { 164 WARN_ON(devres_release(dev, devm_memremap_release, 165 devm_memremap_match, addr)); 166 } 167 EXPORT_SYMBOL(devm_memunmap); 168