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); 129