Commit | Line | Data |
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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _LINUX_NVRAM_H |
3 | #define _LINUX_NVRAM_H | |
4 | ||
1278cf66 | 5 | #include <linux/errno.h> |
607ca46e | 6 | #include <uapi/linux/nvram.h> |
1da177e4 | 7 | |
f9c3a570 FT |
8 | #ifdef CONFIG_PPC |
9 | #include <asm/machdep.h> | |
10 | #endif | |
11 | ||
d5bbb502 FT |
12 | /** |
13 | * struct nvram_ops - NVRAM functionality made available to drivers | |
14 | * @read: validate checksum (if any) then load a range of bytes from NVRAM | |
15 | * @write: store a range of bytes to NVRAM then update checksum (if any) | |
16 | * @read_byte: load a single byte from NVRAM | |
17 | * @write_byte: store a single byte to NVRAM | |
18 | * @get_size: return the fixed number of bytes in the NVRAM | |
19 | * | |
20 | * Architectures which provide an nvram ops struct need not implement all | |
21 | * of these methods. If the NVRAM hardware can be accessed only one byte | |
22 | * at a time then it may be sufficient to provide .read_byte and .write_byte. | |
23 | * If the NVRAM has a checksum (and it is to be checked) the .read and | |
24 | * .write methods can be used to implement that efficiently. | |
25 | * | |
26 | * Portable drivers may use the wrapper functions defined here. | |
27 | * The nvram_read() and nvram_write() functions call the .read and .write | |
28 | * methods when available and fall back on the .read_byte and .write_byte | |
29 | * methods otherwise. | |
30 | */ | |
31 | ||
a084dbf6 FT |
32 | struct nvram_ops { |
33 | ssize_t (*get_size)(void); | |
d5bbb502 FT |
34 | unsigned char (*read_byte)(int); |
35 | void (*write_byte)(unsigned char, int); | |
a084dbf6 FT |
36 | ssize_t (*read)(char *, size_t, loff_t *); |
37 | ssize_t (*write)(char *, size_t, loff_t *); | |
95ac14b8 | 38 | #if defined(CONFIG_X86) || defined(CONFIG_M68K) |
2d58636e FT |
39 | long (*initialize)(void); |
40 | long (*set_checksum)(void); | |
95ac14b8 | 41 | #endif |
a084dbf6 FT |
42 | }; |
43 | ||
44 | extern const struct nvram_ops arch_nvram_ops; | |
45 | ||
1278cf66 FT |
46 | static inline ssize_t nvram_get_size(void) |
47 | { | |
a156c7ba | 48 | #ifdef CONFIG_PPC |
f9c3a570 FT |
49 | if (ppc_md.nvram_size) |
50 | return ppc_md.nvram_size(); | |
a156c7ba | 51 | #else |
a084dbf6 FT |
52 | if (arch_nvram_ops.get_size) |
53 | return arch_nvram_ops.get_size(); | |
a156c7ba | 54 | #endif |
1278cf66 FT |
55 | return -ENODEV; |
56 | } | |
57 | ||
58 | static inline unsigned char nvram_read_byte(int addr) | |
59 | { | |
d5bbb502 | 60 | #ifdef CONFIG_PPC |
f9c3a570 FT |
61 | if (ppc_md.nvram_read_val) |
62 | return ppc_md.nvram_read_val(addr); | |
d5bbb502 FT |
63 | #else |
64 | if (arch_nvram_ops.read_byte) | |
65 | return arch_nvram_ops.read_byte(addr); | |
66 | #endif | |
1278cf66 FT |
67 | return 0xFF; |
68 | } | |
69 | ||
70 | static inline void nvram_write_byte(unsigned char val, int addr) | |
71 | { | |
d5bbb502 | 72 | #ifdef CONFIG_PPC |
f9c3a570 FT |
73 | if (ppc_md.nvram_write_val) |
74 | ppc_md.nvram_write_val(addr, val); | |
d5bbb502 FT |
75 | #else |
76 | if (arch_nvram_ops.write_byte) | |
77 | arch_nvram_ops.write_byte(val, addr); | |
78 | #endif | |
1278cf66 FT |
79 | } |
80 | ||
109b3a89 FT |
81 | static inline ssize_t nvram_read_bytes(char *buf, size_t count, loff_t *ppos) |
82 | { | |
83 | ssize_t nvram_size = nvram_get_size(); | |
84 | loff_t i; | |
85 | char *p = buf; | |
86 | ||
87 | if (nvram_size < 0) | |
88 | return nvram_size; | |
89 | for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count) | |
90 | *p = nvram_read_byte(i); | |
91 | *ppos = i; | |
92 | return p - buf; | |
93 | } | |
94 | ||
95 | static inline ssize_t nvram_write_bytes(char *buf, size_t count, loff_t *ppos) | |
96 | { | |
97 | ssize_t nvram_size = nvram_get_size(); | |
98 | loff_t i; | |
99 | char *p = buf; | |
100 | ||
101 | if (nvram_size < 0) | |
102 | return nvram_size; | |
103 | for (i = *ppos; count > 0 && i < nvram_size; ++i, ++p, --count) | |
104 | nvram_write_byte(*p, i); | |
105 | *ppos = i; | |
106 | return p - buf; | |
107 | } | |
108 | ||
1278cf66 FT |
109 | static inline ssize_t nvram_read(char *buf, size_t count, loff_t *ppos) |
110 | { | |
f9c3a570 FT |
111 | #ifdef CONFIG_PPC |
112 | if (ppc_md.nvram_read) | |
113 | return ppc_md.nvram_read(buf, count, ppos); | |
114 | #else | |
a084dbf6 FT |
115 | if (arch_nvram_ops.read) |
116 | return arch_nvram_ops.read(buf, count, ppos); | |
f9c3a570 | 117 | #endif |
109b3a89 | 118 | return nvram_read_bytes(buf, count, ppos); |
1278cf66 FT |
119 | } |
120 | ||
121 | static inline ssize_t nvram_write(char *buf, size_t count, loff_t *ppos) | |
122 | { | |
f9c3a570 FT |
123 | #ifdef CONFIG_PPC |
124 | if (ppc_md.nvram_write) | |
125 | return ppc_md.nvram_write(buf, count, ppos); | |
126 | #else | |
a084dbf6 FT |
127 | if (arch_nvram_ops.write) |
128 | return arch_nvram_ops.write(buf, count, ppos); | |
f9c3a570 | 129 | #endif |
109b3a89 | 130 | return nvram_write_bytes(buf, count, ppos); |
1278cf66 FT |
131 | } |
132 | ||
1da177e4 | 133 | #endif /* _LINUX_NVRAM_H */ |