Line data Source code
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 0 : static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
17 : {
18 0 : 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 0 : static void *try_ram_remap(resource_size_t offset, size_t size,
31 : unsigned long flags)
32 : {
33 0 : unsigned long pfn = PHYS_PFN(offset);
34 :
35 : /* In the simple case just return the existing linear address */
36 0 : if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) &&
37 0 : arch_memremap_can_ram_remap(offset, size, flags))
38 0 : 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 0 : void *memremap(resource_size_t offset, size_t size, unsigned long flags)
72 : {
73 0 : int is_ram = region_intersects(offset, size,
74 : IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
75 0 : void *addr = NULL;
76 :
77 0 : if (!flags)
78 : return NULL;
79 :
80 0 : if (is_ram == REGION_MIXED) {
81 0 : WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
82 : &offset, (unsigned long) size);
83 0 : return NULL;
84 : }
85 :
86 : /* Try all mapping types requested until one returns non-NULL */
87 0 : 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 0 : if (is_ram == REGION_INTERSECTS)
95 0 : addr = try_ram_remap(offset, size, flags);
96 0 : if (!addr)
97 0 : 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 0 : if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
107 0 : WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
108 : &offset, (unsigned long) size);
109 0 : return NULL;
110 : }
111 :
112 0 : if (!addr && (flags & MEMREMAP_WT))
113 0 : addr = ioremap_wt(offset, size);
114 :
115 0 : if (!addr && (flags & MEMREMAP_WC))
116 0 : addr = ioremap_wc(offset, size);
117 :
118 : return addr;
119 : }
120 : EXPORT_SYMBOL(memremap);
121 :
122 0 : void memunmap(void *addr)
123 : {
124 0 : if (is_ioremap_addr(addr))
125 0 : iounmap((void __iomem *) addr);
126 0 : }
127 : EXPORT_SYMBOL(memunmap);
128 :
129 0 : static void devm_memremap_release(struct device *dev, void *res)
130 : {
131 0 : memunmap(*(void **)res);
132 0 : }
133 :
134 0 : static int devm_memremap_match(struct device *dev, void *res, void *match_data)
135 : {
136 0 : return *(void **)res == match_data;
137 : }
138 :
139 0 : void *devm_memremap(struct device *dev, resource_size_t offset,
140 : size_t size, unsigned long flags)
141 : {
142 0 : void **ptr, *addr;
143 :
144 0 : ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
145 : dev_to_node(dev));
146 0 : if (!ptr)
147 0 : return ERR_PTR(-ENOMEM);
148 :
149 0 : addr = memremap(offset, size, flags);
150 0 : if (addr) {
151 0 : *ptr = addr;
152 0 : devres_add(dev, ptr);
153 : } else {
154 0 : devres_free(ptr);
155 0 : return ERR_PTR(-ENXIO);
156 : }
157 :
158 0 : return addr;
159 : }
160 : EXPORT_SYMBOL(devm_memremap);
161 :
162 0 : void devm_memunmap(struct device *dev, void *addr)
163 : {
164 0 : WARN_ON(devres_release(dev, devm_memremap_release,
165 : devm_memremap_match, addr));
166 0 : }
167 : EXPORT_SYMBOL(devm_memunmap);
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