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5981690d DW |
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> | |
016fec91 | 6 | #include <linux/ioremap.h> |
5981690d | 7 | |
5981690d DW |
8 | #ifndef arch_memremap_wb |
9 | static void *arch_memremap_wb(resource_size_t offset, unsigned long size) | |
10 | { | |
68af0514 | 11 | #ifdef ioremap_cache |
5981690d | 12 | return (__force void *)ioremap_cache(offset, size); |
68af0514 AB |
13 | #else |
14 | return (__force void *)ioremap(offset, size); | |
15 | #endif | |
5981690d DW |
16 | } |
17 | #endif | |
18 | ||
19 | #ifndef arch_memremap_can_ram_remap | |
20 | static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size, | |
21 | unsigned long flags) | |
22 | { | |
23 | return true; | |
24 | } | |
25 | #endif | |
26 | ||
27 | static void *try_ram_remap(resource_size_t offset, size_t size, | |
28 | unsigned long flags) | |
29 | { | |
30 | unsigned long pfn = PHYS_PFN(offset); | |
31 | ||
32 | /* In the simple case just return the existing linear address */ | |
33 | if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) && | |
34 | arch_memremap_can_ram_remap(offset, size, flags)) | |
35 | return __va(offset); | |
36 | ||
37 | return NULL; /* fallback to arch_memremap_wb */ | |
38 | } | |
39 | ||
40 | /** | |
41 | * memremap() - remap an iomem_resource as cacheable memory | |
42 | * @offset: iomem resource start address | |
43 | * @size: size of remap | |
44 | * @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC, | |
45 | * MEMREMAP_ENC, MEMREMAP_DEC | |
46 | * | |
47 | * memremap() is "ioremap" for cases where it is known that the resource | |
48 | * being mapped does not have i/o side effects and the __iomem | |
49 | * annotation is not applicable. In the case of multiple flags, the different | |
50 | * mapping types will be attempted in the order listed below until one of | |
51 | * them succeeds. | |
52 | * | |
53 | * MEMREMAP_WB - matches the default mapping for System RAM on | |
54 | * the architecture. This is usually a read-allocate write-back cache. | |
f6c6010a | 55 | * Moreover, if MEMREMAP_WB is specified and the requested remap region is RAM |
5981690d DW |
56 | * memremap() will bypass establishing a new mapping and instead return |
57 | * a pointer into the direct map. | |
58 | * | |
59 | * MEMREMAP_WT - establish a mapping whereby writes either bypass the | |
60 | * cache or are written through to memory and never exist in a | |
61 | * cache-dirty state with respect to program visibility. Attempts to | |
62 | * map System RAM with this mapping type will fail. | |
63 | * | |
64 | * MEMREMAP_WC - establish a writecombine mapping, whereby writes may | |
65 | * be coalesced together (e.g. in the CPU's write buffers), but is otherwise | |
66 | * uncached. Attempts to map System RAM with this mapping type will fail. | |
67 | */ | |
68 | void *memremap(resource_size_t offset, size_t size, unsigned long flags) | |
69 | { | |
70 | int is_ram = region_intersects(offset, size, | |
71 | IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); | |
72 | void *addr = NULL; | |
73 | ||
74 | if (!flags) | |
75 | return NULL; | |
76 | ||
77 | if (is_ram == REGION_MIXED) { | |
78 | WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n", | |
79 | &offset, (unsigned long) size); | |
80 | return NULL; | |
81 | } | |
82 | ||
83 | /* Try all mapping types requested until one returns non-NULL */ | |
84 | if (flags & MEMREMAP_WB) { | |
85 | /* | |
f6c6010a | 86 | * MEMREMAP_WB is special in that it can be satisfied |
5981690d DW |
87 | * from the direct map. Some archs depend on the |
88 | * capability of memremap() to autodetect cases where | |
89 | * the requested range is potentially in System RAM. | |
90 | */ | |
91 | if (is_ram == REGION_INTERSECTS) | |
92 | addr = try_ram_remap(offset, size, flags); | |
93 | if (!addr) | |
94 | addr = arch_memremap_wb(offset, size); | |
95 | } | |
96 | ||
97 | /* | |
98 | * If we don't have a mapping yet and other request flags are | |
99 | * present then we will be attempting to establish a new virtual | |
100 | * address mapping. Enforce that this mapping is not aliasing | |
101 | * System RAM. | |
102 | */ | |
103 | if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) { | |
104 | WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n", | |
105 | &offset, (unsigned long) size); | |
106 | return NULL; | |
107 | } | |
108 | ||
109 | if (!addr && (flags & MEMREMAP_WT)) | |
110 | addr = ioremap_wt(offset, size); | |
111 | ||
112 | if (!addr && (flags & MEMREMAP_WC)) | |
113 | addr = ioremap_wc(offset, size); | |
114 | ||
115 | return addr; | |
116 | } | |
117 | EXPORT_SYMBOL(memremap); | |
118 | ||
119 | void memunmap(void *addr) | |
120 | { | |
9bd3bb67 | 121 | if (is_ioremap_addr(addr)) |
5981690d DW |
122 | iounmap((void __iomem *) addr); |
123 | } | |
124 | EXPORT_SYMBOL(memunmap); | |
125 | ||
126 | static void devm_memremap_release(struct device *dev, void *res) | |
127 | { | |
128 | memunmap(*(void **)res); | |
129 | } | |
130 | ||
131 | static int devm_memremap_match(struct device *dev, void *res, void *match_data) | |
132 | { | |
133 | return *(void **)res == match_data; | |
134 | } | |
135 | ||
136 | void *devm_memremap(struct device *dev, resource_size_t offset, | |
137 | size_t size, unsigned long flags) | |
138 | { | |
139 | void **ptr, *addr; | |
140 | ||
141 | ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL, | |
142 | dev_to_node(dev)); | |
143 | if (!ptr) | |
144 | return ERR_PTR(-ENOMEM); | |
145 | ||
146 | addr = memremap(offset, size, flags); | |
147 | if (addr) { | |
148 | *ptr = addr; | |
149 | devres_add(dev, ptr); | |
150 | } else { | |
151 | devres_free(ptr); | |
152 | return ERR_PTR(-ENXIO); | |
153 | } | |
154 | ||
155 | return addr; | |
156 | } | |
157 | EXPORT_SYMBOL(devm_memremap); | |
158 | ||
159 | void devm_memunmap(struct device *dev, void *addr) | |
160 | { | |
161 | WARN_ON(devres_release(dev, devm_memremap_release, | |
162 | devm_memremap_match, addr)); | |
163 | } | |
164 | EXPORT_SYMBOL(devm_memunmap); |