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1 | /* |
2 | * Copyright (c) 2011 The Chromium OS Authors. | |
3 | * See file CREDITS for list of people who contributed to this | |
4 | * project. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License as | |
8 | * published by the Free Software Foundation; either version 2 of | |
9 | * the License, or (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, | |
19 | * MA 02111-1307 USA | |
20 | */ | |
21 | ||
22 | ||
23 | /* | |
24 | * This file contains convenience functions for decoding useful and | |
25 | * enlightening information from FDTs. It is intended to be used by device | |
26 | * drivers and board-specific code within U-Boot. It aims to reduce the | |
27 | * amount of FDT munging required within U-Boot itself, so that driver code | |
28 | * changes to support FDT are minimized. | |
29 | */ | |
30 | ||
31 | #include <libfdt.h> | |
32 | ||
33 | /* | |
34 | * A typedef for a physical address. Note that fdt data is always big | |
35 | * endian even on a litle endian machine. | |
36 | */ | |
37 | #ifdef CONFIG_PHYS_64BIT | |
38 | typedef u64 fdt_addr_t; | |
39 | #define FDT_ADDR_T_NONE (-1ULL) | |
40 | #define fdt_addr_to_cpu(reg) be64_to_cpu(reg) | |
41 | #else | |
42 | typedef u32 fdt_addr_t; | |
43 | #define FDT_ADDR_T_NONE (-1U) | |
44 | #define fdt_addr_to_cpu(reg) be32_to_cpu(reg) | |
45 | #endif | |
46 | ||
47 | /* Information obtained about memory from the FDT */ | |
48 | struct fdt_memory { | |
49 | fdt_addr_t start; | |
50 | fdt_addr_t end; | |
51 | }; | |
52 | ||
53 | /** | |
54 | * Compat types that we know about and for which we might have drivers. | |
55 | * Each is named COMPAT_<dir>_<filename> where <dir> is the directory | |
56 | * within drivers. | |
57 | */ | |
58 | enum fdt_compat_id { | |
59 | COMPAT_UNKNOWN, | |
60 | ||
61 | COMPAT_COUNT, | |
62 | }; | |
63 | ||
64 | /** | |
65 | * Find the next numbered alias for a peripheral. This is used to enumerate | |
66 | * all the peripherals of a certain type. | |
67 | * | |
68 | * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then | |
69 | * this function will return a pointer to the node the alias points to, and | |
70 | * then update *upto to 1. Next time you call this function, the next node | |
71 | * will be returned. | |
72 | * | |
73 | * All nodes returned will match the compatible ID, as it is assumed that | |
74 | * all peripherals use the same driver. | |
75 | * | |
76 | * @param blob FDT blob to use | |
77 | * @param name Root name of alias to search for | |
78 | * @param id Compatible ID to look for | |
79 | * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more | |
80 | */ | |
81 | int fdtdec_next_alias(const void *blob, const char *name, | |
82 | enum fdt_compat_id id, int *upto); | |
83 | ||
84 | /** | |
85 | * Look up an address property in a node and return it as an address. | |
86 | * The property must hold either one address with no trailing data or | |
87 | * one address with a length. This is only tested on 32-bit machines. | |
88 | * | |
89 | * @param blob FDT blob | |
90 | * @param node node to examine | |
91 | * @param prop_name name of property to find | |
92 | * @return address, if found, or FDT_ADDR_T_NONE if not | |
93 | */ | |
94 | fdt_addr_t fdtdec_get_addr(const void *blob, int node, | |
95 | const char *prop_name); | |
96 | ||
97 | /** | |
98 | * Look up a 32-bit integer property in a node and return it. The property | |
99 | * must have at least 4 bytes of data. The value of the first cell is | |
100 | * returned. | |
101 | * | |
102 | * @param blob FDT blob | |
103 | * @param node node to examine | |
104 | * @param prop_name name of property to find | |
105 | * @param default_val default value to return if the property is not found | |
106 | * @return integer value, if found, or default_val if not | |
107 | */ | |
108 | s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, | |
109 | s32 default_val); | |
110 | ||
111 | /** | |
112 | * Checks whether a node is enabled. | |
113 | * This looks for a 'status' property. If this exists, then returns 1 if | |
114 | * the status is 'ok' and 0 otherwise. If there is no status property, | |
115 | * it returns the default value. | |
116 | * | |
117 | * @param blob FDT blob | |
118 | * @param node node to examine | |
119 | * @param default_val default value to return if no 'status' property exists | |
120 | * @return integer value 0/1, if found, or default_val if not | |
121 | */ | |
122 | int fdtdec_get_is_enabled(const void *blob, int node, int default_val); | |
123 | ||
124 | /** | |
125 | * Checks whether we have a valid fdt available to control U-Boot, and panic | |
126 | * if not. | |
127 | */ | |
128 | int fdtdec_check_fdt(void); |