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 /* GPIOs are numbered from 0 */ 65 enum { 66 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 67 68 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 69 }; 70 71 /* This is the state of a GPIO pin as defined by the fdt */ 72 struct fdt_gpio_state { 73 const char *name; /* name of the fdt property defining this */ 74 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 75 u8 flags; /* FDT_GPIO_... flags */ 76 }; 77 78 /* This tells us whether a fdt_gpio_state record is valid or not */ 79 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 80 81 /** 82 * Find the next numbered alias for a peripheral. This is used to enumerate 83 * all the peripherals of a certain type. 84 * 85 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 86 * this function will return a pointer to the node the alias points to, and 87 * then update *upto to 1. Next time you call this function, the next node 88 * will be returned. 89 * 90 * All nodes returned will match the compatible ID, as it is assumed that 91 * all peripherals use the same driver. 92 * 93 * @param blob FDT blob to use 94 * @param name Root name of alias to search for 95 * @param id Compatible ID to look for 96 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 97 */ 98 int fdtdec_next_alias(const void *blob, const char *name, 99 enum fdt_compat_id id, int *upto); 100 101 /** 102 * Find the next compatible node for a peripheral. 103 * 104 * Do the first call with node = 0. This function will return a pointer to 105 * the next compatible node. Next time you call this function, pass the 106 * value returned, and the next node will be provided. 107 * 108 * @param blob FDT blob to use 109 * @param node Start node for search 110 * @param id Compatible ID to look for (enum fdt_compat_id) 111 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 112 */ 113 int fdtdec_next_compatible(const void *blob, int node, 114 enum fdt_compat_id id); 115 116 /** 117 * Look up an address property in a node and return it as an address. 118 * The property must hold either one address with no trailing data or 119 * one address with a length. This is only tested on 32-bit machines. 120 * 121 * @param blob FDT blob 122 * @param node node to examine 123 * @param prop_name name of property to find 124 * @return address, if found, or FDT_ADDR_T_NONE if not 125 */ 126 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 127 const char *prop_name); 128 129 /** 130 * Look up a 32-bit integer property in a node and return it. The property 131 * must have at least 4 bytes of data. The value of the first cell is 132 * returned. 133 * 134 * @param blob FDT blob 135 * @param node node to examine 136 * @param prop_name name of property to find 137 * @param default_val default value to return if the property is not found 138 * @return integer value, if found, or default_val if not 139 */ 140 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 141 s32 default_val); 142 143 /** 144 * Checks whether a node is enabled. 145 * This looks for a 'status' property. If this exists, then returns 1 if 146 * the status is 'ok' and 0 otherwise. If there is no status property, 147 * it returns 1 on the assumption that anything mentioned should be enabled 148 * by default. 149 * 150 * @param blob FDT blob 151 * @param node node to examine 152 * @return integer value 0 (not enabled) or 1 (enabled) 153 */ 154 int fdtdec_get_is_enabled(const void *blob, int node); 155 156 /** 157 * Checks whether we have a valid fdt available to control U-Boot, and panic 158 * if not. 159 */ 160 int fdtdec_check_fdt(void); 161 162 /** 163 * Find the nodes for a peripheral and return a list of them in the correct 164 * order. This is used to enumerate all the peripherals of a certain type. 165 * 166 * To use this, optionally set up a /aliases node with alias properties for 167 * a peripheral. For example, for usb you could have: 168 * 169 * aliases { 170 * usb0 = "/ehci@c5008000"; 171 * usb1 = "/ehci@c5000000"; 172 * }; 173 * 174 * Pass "usb" as the name to this function and will return a list of two 175 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 176 * 177 * All nodes returned will match the compatible ID, as it is assumed that 178 * all peripherals use the same driver. 179 * 180 * If no alias node is found, then the node list will be returned in the 181 * order found in the fdt. If the aliases mention a node which doesn't 182 * exist, then this will be ignored. If nodes are found with no aliases, 183 * they will be added in any order. 184 * 185 * If there is a gap in the aliases, then this function return a 0 node at 186 * that position. The return value will also count these gaps. 187 * 188 * This function checks node properties and will not return nodes which are 189 * marked disabled (status = "disabled"). 190 * 191 * @param blob FDT blob to use 192 * @param name Root name of alias to search for 193 * @param id Compatible ID to look for 194 * @param node_list Place to put list of found nodes 195 * @param maxcount Maximum number of nodes to find 196 * @return number of nodes found on success, FTD_ERR_... on error 197 */ 198 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 199 enum fdt_compat_id id, int *node_list, int maxcount); 200 201 /* 202 * Get the name for a compatible ID 203 * 204 * @param id Compatible ID to look for 205 * @return compatible string for that id 206 */ 207 const char *fdtdec_get_compatible(enum fdt_compat_id id); 208 209 /* Look up a phandle and follow it to its node. Then return the offset 210 * of that node. 211 * 212 * @param blob FDT blob 213 * @param node node to examine 214 * @param prop_name name of property to find 215 * @return node offset if found, -ve error code on error 216 */ 217 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 218 219 /** 220 * Look up a property in a node and return its contents in an integer 221 * array of given length. The property must have at least enough data for 222 * the array (4*count bytes). It may have more, but this will be ignored. 223 * 224 * @param blob FDT blob 225 * @param node node to examine 226 * @param prop_name name of property to find 227 * @param array array to fill with data 228 * @param count number of array elements 229 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 230 * or -FDT_ERR_BADLAYOUT if not enough data 231 */ 232 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 233 u32 *array, int count); 234 235 /** 236 * Look up a boolean property in a node and return it. 237 * 238 * A boolean properly is true if present in the device tree and false if not 239 * present, regardless of its value. 240 * 241 * @param blob FDT blob 242 * @param node node to examine 243 * @param prop_name name of property to find 244 * @return 1 if the properly is present; 0 if it isn't present 245 */ 246 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 247 248 /** 249 * Decode a single GPIOs from an FDT. 250 * 251 * If the property is not found, then the GPIO structure will still be 252 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 253 * provide optional GPIOs. 254 * 255 * @param blob FDT blob to use 256 * @param node Node to look at 257 * @param prop_name Node property name 258 * @param gpio gpio elements to fill from FDT 259 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 260 */ 261 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 262 struct fdt_gpio_state *gpio); 263 264 /** 265 * Set up a GPIO pin according to the provided gpio information. At present this 266 * just requests the GPIO. 267 * 268 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 269 * deal with optional GPIOs. 270 * 271 * @param gpio GPIO info to use for set up 272 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 273 */ 274 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 275