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 | #include <linux/ioremap.h> |
7 | |
8 | #ifndef arch_memremap_wb |
9 | static void *arch_memremap_wb(resource_size_t offset, unsigned long size) |
10 | { |
11 | #ifdef ioremap_cache |
12 | return (__force void *)ioremap_cache(offset, size); |
13 | #else |
14 | return (__force void *)ioremap(offset, size); |
15 | #endif |
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. |
55 | * Moreover, if MEMREMAP_WB is specified and the requested remap region is RAM |
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, desc: 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 | /* |
86 | * MEMREMAP_WB is special in that it can be satisfied |
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 | { |
121 | if (is_ioremap_addr(x: addr)) |
122 | iounmap(addr: (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(error: -ENOMEM); |
145 | |
146 | addr = memremap(offset, size, flags); |
147 | if (addr) { |
148 | *ptr = addr; |
149 | devres_add(dev, res: ptr); |
150 | } else { |
151 | devres_free(res: ptr); |
152 | return ERR_PTR(error: -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); |
165 | |