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e169cfbe GL |
1 | /* |
2 | * Functions for working with the Flattened Device Tree data format | |
3 | * | |
4 | * Copyright 2009 Benjamin Herrenschmidt, IBM Corp | |
5 | * benh@kernel.crashing.org | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * version 2 as published by the Free Software Foundation. | |
10 | */ | |
11 | ||
12 | #include <linux/of.h> | |
13 | #include <linux/of_fdt.h> | |
14 | ||
15 | struct boot_param_header *initial_boot_params; | |
16 | ||
17 | char *find_flat_dt_string(u32 offset) | |
18 | { | |
19 | return ((char *)initial_boot_params) + | |
20 | initial_boot_params->off_dt_strings + offset; | |
21 | } | |
c8cb7a59 GL |
22 | |
23 | /** | |
24 | * of_scan_flat_dt - scan flattened tree blob and call callback on each. | |
25 | * @it: callback function | |
26 | * @data: context data pointer | |
27 | * | |
28 | * This function is used to scan the flattened device-tree, it is | |
29 | * used to extract the memory information at boot before we can | |
30 | * unflatten the tree | |
31 | */ | |
32 | int __init of_scan_flat_dt(int (*it)(unsigned long node, | |
33 | const char *uname, int depth, | |
34 | void *data), | |
35 | void *data) | |
36 | { | |
37 | unsigned long p = ((unsigned long)initial_boot_params) + | |
38 | initial_boot_params->off_dt_struct; | |
39 | int rc = 0; | |
40 | int depth = -1; | |
41 | ||
42 | do { | |
43 | u32 tag = *((u32 *)p); | |
44 | char *pathp; | |
45 | ||
46 | p += 4; | |
47 | if (tag == OF_DT_END_NODE) { | |
48 | depth--; | |
49 | continue; | |
50 | } | |
51 | if (tag == OF_DT_NOP) | |
52 | continue; | |
53 | if (tag == OF_DT_END) | |
54 | break; | |
55 | if (tag == OF_DT_PROP) { | |
56 | u32 sz = *((u32 *)p); | |
57 | p += 8; | |
58 | if (initial_boot_params->version < 0x10) | |
59 | p = _ALIGN(p, sz >= 8 ? 8 : 4); | |
60 | p += sz; | |
61 | p = _ALIGN(p, 4); | |
62 | continue; | |
63 | } | |
64 | if (tag != OF_DT_BEGIN_NODE) { | |
65 | pr_err("Invalid tag %x in flat device tree!\n", tag); | |
66 | return -EINVAL; | |
67 | } | |
68 | depth++; | |
69 | pathp = (char *)p; | |
70 | p = _ALIGN(p + strlen(pathp) + 1, 4); | |
71 | if ((*pathp) == '/') { | |
72 | char *lp, *np; | |
73 | for (lp = NULL, np = pathp; *np; np++) | |
74 | if ((*np) == '/') | |
75 | lp = np+1; | |
76 | if (lp != NULL) | |
77 | pathp = lp; | |
78 | } | |
79 | rc = it(p, pathp, depth, data); | |
80 | if (rc != 0) | |
81 | break; | |
82 | } while (1); | |
83 | ||
84 | return rc; | |
85 | } | |
819d2819 GL |
86 | |
87 | /** | |
88 | * of_get_flat_dt_root - find the root node in the flat blob | |
89 | */ | |
90 | unsigned long __init of_get_flat_dt_root(void) | |
91 | { | |
92 | unsigned long p = ((unsigned long)initial_boot_params) + | |
93 | initial_boot_params->off_dt_struct; | |
94 | ||
95 | while (*((u32 *)p) == OF_DT_NOP) | |
96 | p += 4; | |
97 | BUG_ON(*((u32 *)p) != OF_DT_BEGIN_NODE); | |
98 | p += 4; | |
99 | return _ALIGN(p + strlen((char *)p) + 1, 4); | |
100 | } | |
101 |