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92281dee DW |
1 | /* |
2 | * Copyright(c) 2015 Intel Corporation. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of version 2 of the GNU General Public License as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | */ | |
13 | #include <linux/types.h> | |
14 | #include <linux/io.h> | |
15 | #include <linux/mm.h> | |
16 | ||
17 | #ifndef ioremap_cache | |
18 | /* temporary while we convert existing ioremap_cache users to memremap */ | |
19 | __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size) | |
20 | { | |
21 | return ioremap(offset, size); | |
22 | } | |
23 | #endif | |
24 | ||
25 | /** | |
26 | * memremap() - remap an iomem_resource as cacheable memory | |
27 | * @offset: iomem resource start address | |
28 | * @size: size of remap | |
29 | * @flags: either MEMREMAP_WB or MEMREMAP_WT | |
30 | * | |
31 | * memremap() is "ioremap" for cases where it is known that the resource | |
32 | * being mapped does not have i/o side effects and the __iomem | |
33 | * annotation is not applicable. | |
34 | * | |
35 | * MEMREMAP_WB - matches the default mapping for "System RAM" on | |
36 | * the architecture. This is usually a read-allocate write-back cache. | |
37 | * Morever, if MEMREMAP_WB is specified and the requested remap region is RAM | |
38 | * memremap() will bypass establishing a new mapping and instead return | |
39 | * a pointer into the direct map. | |
40 | * | |
41 | * MEMREMAP_WT - establish a mapping whereby writes either bypass the | |
42 | * cache or are written through to memory and never exist in a | |
43 | * cache-dirty state with respect to program visibility. Attempts to | |
44 | * map "System RAM" with this mapping type will fail. | |
45 | */ | |
46 | void *memremap(resource_size_t offset, size_t size, unsigned long flags) | |
47 | { | |
48 | int is_ram = region_intersects(offset, size, "System RAM"); | |
49 | void *addr = NULL; | |
50 | ||
51 | if (is_ram == REGION_MIXED) { | |
52 | WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n", | |
53 | &offset, (unsigned long) size); | |
54 | return NULL; | |
55 | } | |
56 | ||
57 | /* Try all mapping types requested until one returns non-NULL */ | |
58 | if (flags & MEMREMAP_WB) { | |
59 | flags &= ~MEMREMAP_WB; | |
60 | /* | |
61 | * MEMREMAP_WB is special in that it can be satisifed | |
62 | * from the direct map. Some archs depend on the | |
63 | * capability of memremap() to autodetect cases where | |
64 | * the requested range is potentially in "System RAM" | |
65 | */ | |
66 | if (is_ram == REGION_INTERSECTS) | |
67 | addr = __va(offset); | |
68 | else | |
69 | addr = ioremap_cache(offset, size); | |
70 | } | |
71 | ||
72 | /* | |
73 | * If we don't have a mapping yet and more request flags are | |
74 | * pending then we will be attempting to establish a new virtual | |
75 | * address mapping. Enforce that this mapping is not aliasing | |
76 | * "System RAM" | |
77 | */ | |
78 | if (!addr && is_ram == REGION_INTERSECTS && flags) { | |
79 | WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n", | |
80 | &offset, (unsigned long) size); | |
81 | return NULL; | |
82 | } | |
83 | ||
84 | if (!addr && (flags & MEMREMAP_WT)) { | |
85 | flags &= ~MEMREMAP_WT; | |
86 | addr = ioremap_wt(offset, size); | |
87 | } | |
88 | ||
89 | return addr; | |
90 | } | |
91 | EXPORT_SYMBOL(memremap); | |
92 | ||
93 | void memunmap(void *addr) | |
94 | { | |
95 | if (is_vmalloc_addr(addr)) | |
96 | iounmap((void __iomem *) addr); | |
97 | } | |
98 | EXPORT_SYMBOL(memunmap); |