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61031952 RZ |
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 | #ifndef __PMEM_H__ | |
14 | #define __PMEM_H__ | |
15 | ||
16 | #include <linux/io.h> | |
17 | ||
18 | #ifdef CONFIG_ARCH_HAS_PMEM_API | |
19 | #include <asm/cacheflush.h> | |
20 | #else | |
21 | static inline void arch_wmb_pmem(void) | |
22 | { | |
23 | BUG(); | |
24 | } | |
25 | ||
26 | static inline bool __arch_has_wmb_pmem(void) | |
27 | { | |
28 | return false; | |
29 | } | |
30 | ||
61031952 RZ |
31 | static inline void arch_memcpy_to_pmem(void __pmem *dst, const void *src, |
32 | size_t n) | |
33 | { | |
34 | BUG(); | |
35 | } | |
36 | #endif | |
37 | ||
38 | /* | |
39 | * Architectures that define ARCH_HAS_PMEM_API must provide | |
e836a256 DW |
40 | * implementations for arch_memcpy_to_pmem(), arch_wmb_pmem(), and |
41 | * __arch_has_wmb_pmem(). | |
61031952 RZ |
42 | */ |
43 | ||
44 | static inline void memcpy_from_pmem(void *dst, void __pmem const *src, size_t size) | |
45 | { | |
46 | memcpy(dst, (void __force const *) src, size); | |
47 | } | |
48 | ||
708ab62b | 49 | static inline void memunmap_pmem(struct device *dev, void __pmem *addr) |
61031952 | 50 | { |
708ab62b | 51 | devm_memunmap(dev, (void __force *) addr); |
61031952 RZ |
52 | } |
53 | ||
54 | /** | |
55 | * arch_has_wmb_pmem - true if wmb_pmem() ensures durability | |
56 | * | |
57 | * For a given cpu implementation within an architecture it is possible | |
58 | * that wmb_pmem() resolves to a nop. In the case this returns | |
59 | * false, pmem api users are unable to ensure durability and may want to | |
60 | * fall back to a different data consistency model, or otherwise notify | |
61 | * the user. | |
62 | */ | |
63 | static inline bool arch_has_wmb_pmem(void) | |
64 | { | |
65 | if (IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API)) | |
66 | return __arch_has_wmb_pmem(); | |
67 | return false; | |
68 | } | |
69 | ||
70 | static inline bool arch_has_pmem_api(void) | |
71 | { | |
72 | return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API) && arch_has_wmb_pmem(); | |
73 | } | |
74 | ||
75 | /* | |
76 | * These defaults seek to offer decent performance and minimize the | |
77 | * window between i/o completion and writes being durable on media. | |
78 | * However, it is undefined / architecture specific whether | |
79 | * default_memremap_pmem + default_memcpy_to_pmem is sufficient for | |
80 | * making data durable relative to i/o completion. | |
81 | */ | |
e836a256 | 82 | static inline void default_memcpy_to_pmem(void __pmem *dst, const void *src, |
61031952 RZ |
83 | size_t size) |
84 | { | |
85 | memcpy((void __force *) dst, src, size); | |
86 | } | |
87 | ||
61031952 RZ |
88 | /** |
89 | * memremap_pmem - map physical persistent memory for pmem api | |
90 | * @offset: physical address of persistent memory | |
91 | * @size: size of the mapping | |
92 | * | |
93 | * Establish a mapping of the architecture specific memory type expected | |
94 | * by memcpy_to_pmem() and wmb_pmem(). For example, it may be | |
95 | * the case that an uncacheable or writethrough mapping is sufficient, | |
96 | * or a writeback mapping provided memcpy_to_pmem() and | |
97 | * wmb_pmem() arrange for the data to be written through the | |
98 | * cache to persistent media. | |
99 | */ | |
708ab62b CH |
100 | static inline void __pmem *memremap_pmem(struct device *dev, |
101 | resource_size_t offset, unsigned long size) | |
61031952 | 102 | { |
e836a256 | 103 | #ifdef ARCH_MEMREMAP_PMEM |
708ab62b CH |
104 | return (void __pmem *) devm_memremap(dev, offset, size, |
105 | ARCH_MEMREMAP_PMEM); | |
e836a256 | 106 | #else |
708ab62b CH |
107 | return (void __pmem *) devm_memremap(dev, offset, size, |
108 | MEMREMAP_WT); | |
e836a256 | 109 | #endif |
61031952 RZ |
110 | } |
111 | ||
112 | /** | |
113 | * memcpy_to_pmem - copy data to persistent memory | |
114 | * @dst: destination buffer for the copy | |
115 | * @src: source buffer for the copy | |
116 | * @n: length of the copy in bytes | |
117 | * | |
118 | * Perform a memory copy that results in the destination of the copy | |
119 | * being effectively evicted from, or never written to, the processor | |
120 | * cache hierarchy after the copy completes. After memcpy_to_pmem() | |
121 | * data may still reside in cpu or platform buffers, so this operation | |
122 | * must be followed by a wmb_pmem(). | |
123 | */ | |
124 | static inline void memcpy_to_pmem(void __pmem *dst, const void *src, size_t n) | |
125 | { | |
126 | if (arch_has_pmem_api()) | |
127 | arch_memcpy_to_pmem(dst, src, n); | |
128 | else | |
129 | default_memcpy_to_pmem(dst, src, n); | |
130 | } | |
131 | ||
132 | /** | |
133 | * wmb_pmem - synchronize writes to persistent memory | |
134 | * | |
135 | * After a series of memcpy_to_pmem() operations this drains data from | |
136 | * cpu write buffers and any platform (memory controller) buffers to | |
137 | * ensure that written data is durable on persistent memory media. | |
138 | */ | |
139 | static inline void wmb_pmem(void) | |
140 | { | |
141 | if (arch_has_pmem_api()) | |
142 | arch_wmb_pmem(); | |
143 | } | |
144 | #endif /* __PMEM_H__ */ |