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 COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra2 i2c */ 62 COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra2 dvc (really just i2c) */ 63 64 COMPAT_COUNT, 65 }; 66 67 /* GPIOs are numbered from 0 */ 68 enum { 69 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 70 71 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 72 }; 73 74 /* This is the state of a GPIO pin as defined by the fdt */ 75 struct fdt_gpio_state { 76 const char *name; /* name of the fdt property defining this */ 77 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 78 u8 flags; /* FDT_GPIO_... flags */ 79 }; 80 81 /* This tells us whether a fdt_gpio_state record is valid or not */ 82 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 83 84 /** 85 * Find the next numbered alias for a peripheral. This is used to enumerate 86 * all the peripherals of a certain type. 87 * 88 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 89 * this function will return a pointer to the node the alias points to, and 90 * then update *upto to 1. Next time you call this function, the next node 91 * will be returned. 92 * 93 * All nodes returned will match the compatible ID, as it is assumed that 94 * all peripherals use the same driver. 95 * 96 * @param blob FDT blob to use 97 * @param name Root name of alias to search for 98 * @param id Compatible ID to look for 99 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 100 */ 101 int fdtdec_next_alias(const void *blob, const char *name, 102 enum fdt_compat_id id, int *upto); 103 104 /** 105 * Find the next compatible node for a peripheral. 106 * 107 * Do the first call with node = 0. This function will return a pointer to 108 * the next compatible node. Next time you call this function, pass the 109 * value returned, and the next node will be provided. 110 * 111 * @param blob FDT blob to use 112 * @param node Start node for search 113 * @param id Compatible ID to look for (enum fdt_compat_id) 114 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 115 */ 116 int fdtdec_next_compatible(const void *blob, int node, 117 enum fdt_compat_id id); 118 119 /** 120 * Find the next compatible subnode for a peripheral. 121 * 122 * Do the first call with node set to the parent and depth = 0. This 123 * function will return the offset of the next compatible node. Next time 124 * you call this function, pass the node value returned last time, with 125 * depth unchanged, and the next node will be provided. 126 * 127 * @param blob FDT blob to use 128 * @param node Start node for search 129 * @param id Compatible ID to look for (enum fdt_compat_id) 130 * @param depthp Current depth (set to 0 before first call) 131 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 132 */ 133 int fdtdec_next_compatible_subnode(const void *blob, int node, 134 enum fdt_compat_id id, int *depthp); 135 136 /** 137 * Look up an address property in a node and return it as an address. 138 * The property must hold either one address with no trailing data or 139 * one address with a length. This is only tested on 32-bit machines. 140 * 141 * @param blob FDT blob 142 * @param node node to examine 143 * @param prop_name name of property to find 144 * @return address, if found, or FDT_ADDR_T_NONE if not 145 */ 146 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 147 const char *prop_name); 148 149 /** 150 * Look up a 32-bit integer property in a node and return it. The property 151 * must have at least 4 bytes of data. The value of the first cell is 152 * returned. 153 * 154 * @param blob FDT blob 155 * @param node node to examine 156 * @param prop_name name of property to find 157 * @param default_val default value to return if the property is not found 158 * @return integer value, if found, or default_val if not 159 */ 160 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 161 s32 default_val); 162 163 /** 164 * Checks whether a node is enabled. 165 * This looks for a 'status' property. If this exists, then returns 1 if 166 * the status is 'ok' and 0 otherwise. If there is no status property, 167 * it returns 1 on the assumption that anything mentioned should be enabled 168 * by default. 169 * 170 * @param blob FDT blob 171 * @param node node to examine 172 * @return integer value 0 (not enabled) or 1 (enabled) 173 */ 174 int fdtdec_get_is_enabled(const void *blob, int node); 175 176 /** 177 * Make sure we have a valid fdt available to control U-Boot. 178 * 179 * If not, a message is printed to the console if the console is ready. 180 * 181 * @return 0 if all ok, -1 if not 182 */ 183 int fdtdec_prepare_fdt(void); 184 185 /** 186 * Checks that we have a valid fdt available to control U-Boot. 187 188 * However, if not then for the moment nothing is done, since this function 189 * is called too early to panic(). 190 * 191 * @returns 0 192 */ 193 int fdtdec_check_fdt(void); 194 195 /** 196 * Find the nodes for a peripheral and return a list of them in the correct 197 * order. This is used to enumerate all the peripherals of a certain type. 198 * 199 * To use this, optionally set up a /aliases node with alias properties for 200 * a peripheral. For example, for usb you could have: 201 * 202 * aliases { 203 * usb0 = "/ehci@c5008000"; 204 * usb1 = "/ehci@c5000000"; 205 * }; 206 * 207 * Pass "usb" as the name to this function and will return a list of two 208 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 209 * 210 * All nodes returned will match the compatible ID, as it is assumed that 211 * all peripherals use the same driver. 212 * 213 * If no alias node is found, then the node list will be returned in the 214 * order found in the fdt. If the aliases mention a node which doesn't 215 * exist, then this will be ignored. If nodes are found with no aliases, 216 * they will be added in any order. 217 * 218 * If there is a gap in the aliases, then this function return a 0 node at 219 * that position. The return value will also count these gaps. 220 * 221 * This function checks node properties and will not return nodes which are 222 * marked disabled (status = "disabled"). 223 * 224 * @param blob FDT blob to use 225 * @param name Root name of alias to search for 226 * @param id Compatible ID to look for 227 * @param node_list Place to put list of found nodes 228 * @param maxcount Maximum number of nodes to find 229 * @return number of nodes found on success, FTD_ERR_... on error 230 */ 231 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 232 enum fdt_compat_id id, int *node_list, int maxcount); 233 234 /* 235 * This function is similar to fdtdec_find_aliases_for_id() except that it 236 * adds to the node_list that is passed in. Any 0 elements are considered 237 * available for allocation - others are considered already used and are 238 * skipped. 239 * 240 * You can use this by calling fdtdec_find_aliases_for_id() with an 241 * uninitialised array, then setting the elements that are returned to -1, 242 * say, then calling this function, perhaps with a different compat id. 243 * Any elements you get back that are >0 are new nodes added by the call 244 * to this function. 245 * 246 * Note that if you have some nodes with aliases and some without, you are 247 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with 248 * one compat_id may fill in positions for which you have aliases defined 249 * for another compat_id. When you later call *this* function with the second 250 * compat_id, the alias positions may already be used. A debug warning may 251 * be generated in this case, but it is safest to define aliases for all 252 * nodes when you care about the ordering. 253 */ 254 int fdtdec_add_aliases_for_id(const void *blob, const char *name, 255 enum fdt_compat_id id, int *node_list, int maxcount); 256 257 /* 258 * Get the name for a compatible ID 259 * 260 * @param id Compatible ID to look for 261 * @return compatible string for that id 262 */ 263 const char *fdtdec_get_compatible(enum fdt_compat_id id); 264 265 /* Look up a phandle and follow it to its node. Then return the offset 266 * of that node. 267 * 268 * @param blob FDT blob 269 * @param node node to examine 270 * @param prop_name name of property to find 271 * @return node offset if found, -ve error code on error 272 */ 273 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 274 275 /** 276 * Look up a property in a node and return its contents in an integer 277 * array of given length. The property must have at least enough data for 278 * the array (4*count bytes). It may have more, but this will be ignored. 279 * 280 * @param blob FDT blob 281 * @param node node to examine 282 * @param prop_name name of property to find 283 * @param array array to fill with data 284 * @param count number of array elements 285 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 286 * or -FDT_ERR_BADLAYOUT if not enough data 287 */ 288 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 289 u32 *array, int count); 290 291 /** 292 * Look up a property in a node and return a pointer to its contents as a 293 * unsigned int array of given length. The property must have at least enough 294 * data for the array ('count' cells). It may have more, but this will be 295 * ignored. The data is not copied. 296 * 297 * Note that you must access elements of the array with fdt32_to_cpu(), 298 * since the elements will be big endian even on a little endian machine. 299 * 300 * @param blob FDT blob 301 * @param node node to examine 302 * @param prop_name name of property to find 303 * @param count number of array elements 304 * @return pointer to array if found, or NULL if the property is not 305 * found or there is not enough data 306 */ 307 const u32 *fdtdec_locate_array(const void *blob, int node, 308 const char *prop_name, int count); 309 310 /** 311 * Look up a boolean property in a node and return it. 312 * 313 * A boolean properly is true if present in the device tree and false if not 314 * present, regardless of its value. 315 * 316 * @param blob FDT blob 317 * @param node node to examine 318 * @param prop_name name of property to find 319 * @return 1 if the properly is present; 0 if it isn't present 320 */ 321 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 322 323 /** 324 * Decode a single GPIOs from an FDT. 325 * 326 * If the property is not found, then the GPIO structure will still be 327 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 328 * provide optional GPIOs. 329 * 330 * @param blob FDT blob to use 331 * @param node Node to look at 332 * @param prop_name Node property name 333 * @param gpio gpio elements to fill from FDT 334 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 335 */ 336 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 337 struct fdt_gpio_state *gpio); 338 339 /** 340 * Set up a GPIO pin according to the provided gpio information. At present this 341 * just requests the GPIO. 342 * 343 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 344 * deal with optional GPIOs. 345 * 346 * @param gpio GPIO info to use for set up 347 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 348 */ 349 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 350