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 COMPAT_NVIDIA_TEGRA20_USB, /* Tegra2 USB port */ 61 62 COMPAT_COUNT, 63 }; 64 65 /* GPIOs are numbered from 0 */ 66 enum { 67 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 68 69 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 70 }; 71 72 /* This is the state of a GPIO pin as defined by the fdt */ 73 struct fdt_gpio_state { 74 const char *name; /* name of the fdt property defining this */ 75 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 76 u8 flags; /* FDT_GPIO_... flags */ 77 }; 78 79 /* This tells us whether a fdt_gpio_state record is valid or not */ 80 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 81 82 /** 83 * Find the next numbered alias for a peripheral. This is used to enumerate 84 * all the peripherals of a certain type. 85 * 86 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 87 * this function will return a pointer to the node the alias points to, and 88 * then update *upto to 1. Next time you call this function, the next node 89 * will be returned. 90 * 91 * All nodes returned will match the compatible ID, as it is assumed that 92 * all peripherals use the same driver. 93 * 94 * @param blob FDT blob to use 95 * @param name Root name of alias to search for 96 * @param id Compatible ID to look for 97 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 98 */ 99 int fdtdec_next_alias(const void *blob, const char *name, 100 enum fdt_compat_id id, int *upto); 101 102 /** 103 * Find the next compatible node for a peripheral. 104 * 105 * Do the first call with node = 0. This function will return a pointer to 106 * the next compatible node. Next time you call this function, pass the 107 * value returned, and the next node will be provided. 108 * 109 * @param blob FDT blob to use 110 * @param node Start node for search 111 * @param id Compatible ID to look for (enum fdt_compat_id) 112 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 113 */ 114 int fdtdec_next_compatible(const void *blob, int node, 115 enum fdt_compat_id id); 116 117 /** 118 * Look up an address property in a node and return it as an address. 119 * The property must hold either one address with no trailing data or 120 * one address with a length. This is only tested on 32-bit machines. 121 * 122 * @param blob FDT blob 123 * @param node node to examine 124 * @param prop_name name of property to find 125 * @return address, if found, or FDT_ADDR_T_NONE if not 126 */ 127 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 128 const char *prop_name); 129 130 /** 131 * Look up a 32-bit integer property in a node and return it. The property 132 * must have at least 4 bytes of data. The value of the first cell is 133 * returned. 134 * 135 * @param blob FDT blob 136 * @param node node to examine 137 * @param prop_name name of property to find 138 * @param default_val default value to return if the property is not found 139 * @return integer value, if found, or default_val if not 140 */ 141 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 142 s32 default_val); 143 144 /** 145 * Checks whether a node is enabled. 146 * This looks for a 'status' property. If this exists, then returns 1 if 147 * the status is 'ok' and 0 otherwise. If there is no status property, 148 * it returns 1 on the assumption that anything mentioned should be enabled 149 * by default. 150 * 151 * @param blob FDT blob 152 * @param node node to examine 153 * @return integer value 0 (not enabled) or 1 (enabled) 154 */ 155 int fdtdec_get_is_enabled(const void *blob, int node); 156 157 /** 158 * Checks whether we have a valid fdt available to control U-Boot, and panic 159 * if not. 160 */ 161 int fdtdec_check_fdt(void); 162 163 /** 164 * Find the nodes for a peripheral and return a list of them in the correct 165 * order. This is used to enumerate all the peripherals of a certain type. 166 * 167 * To use this, optionally set up a /aliases node with alias properties for 168 * a peripheral. For example, for usb you could have: 169 * 170 * aliases { 171 * usb0 = "/ehci@c5008000"; 172 * usb1 = "/ehci@c5000000"; 173 * }; 174 * 175 * Pass "usb" as the name to this function and will return a list of two 176 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 177 * 178 * All nodes returned will match the compatible ID, as it is assumed that 179 * all peripherals use the same driver. 180 * 181 * If no alias node is found, then the node list will be returned in the 182 * order found in the fdt. If the aliases mention a node which doesn't 183 * exist, then this will be ignored. If nodes are found with no aliases, 184 * they will be added in any order. 185 * 186 * If there is a gap in the aliases, then this function return a 0 node at 187 * that position. The return value will also count these gaps. 188 * 189 * This function checks node properties and will not return nodes which are 190 * marked disabled (status = "disabled"). 191 * 192 * @param blob FDT blob to use 193 * @param name Root name of alias to search for 194 * @param id Compatible ID to look for 195 * @param node_list Place to put list of found nodes 196 * @param maxcount Maximum number of nodes to find 197 * @return number of nodes found on success, FTD_ERR_... on error 198 */ 199 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 200 enum fdt_compat_id id, int *node_list, int maxcount); 201 202 /* 203 * Get the name for a compatible ID 204 * 205 * @param id Compatible ID to look for 206 * @return compatible string for that id 207 */ 208 const char *fdtdec_get_compatible(enum fdt_compat_id id); 209 210 /* Look up a phandle and follow it to its node. Then return the offset 211 * of that node. 212 * 213 * @param blob FDT blob 214 * @param node node to examine 215 * @param prop_name name of property to find 216 * @return node offset if found, -ve error code on error 217 */ 218 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 219 220 /** 221 * Look up a property in a node and return its contents in an integer 222 * array of given length. The property must have at least enough data for 223 * the array (4*count bytes). It may have more, but this will be ignored. 224 * 225 * @param blob FDT blob 226 * @param node node to examine 227 * @param prop_name name of property to find 228 * @param array array to fill with data 229 * @param count number of array elements 230 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 231 * or -FDT_ERR_BADLAYOUT if not enough data 232 */ 233 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 234 u32 *array, int count); 235 236 /** 237 * Look up a boolean property in a node and return it. 238 * 239 * A boolean properly is true if present in the device tree and false if not 240 * present, regardless of its value. 241 * 242 * @param blob FDT blob 243 * @param node node to examine 244 * @param prop_name name of property to find 245 * @return 1 if the properly is present; 0 if it isn't present 246 */ 247 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 248 249 /** 250 * Decode a single GPIOs from an FDT. 251 * 252 * If the property is not found, then the GPIO structure will still be 253 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 254 * provide optional GPIOs. 255 * 256 * @param blob FDT blob to use 257 * @param node Node to look at 258 * @param prop_name Node property name 259 * @param gpio gpio elements to fill from FDT 260 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 261 */ 262 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 263 struct fdt_gpio_state *gpio); 264 265 /** 266 * Set up a GPIO pin according to the provided gpio information. At present this 267 * just requests the GPIO. 268 * 269 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 270 * deal with optional GPIOs. 271 * 272 * @param gpio GPIO info to use for set up 273 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 274 */ 275 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 276