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 COMPAT_NVIDIA_TEGRA20_EMC, /* Tegra2 memory controller */ 64 COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra2 memory timing table */ 65 66 COMPAT_COUNT, 67 }; 68 69 /* GPIOs are numbered from 0 */ 70 enum { 71 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 72 73 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 74 }; 75 76 /* This is the state of a GPIO pin as defined by the fdt */ 77 struct fdt_gpio_state { 78 const char *name; /* name of the fdt property defining this */ 79 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 80 u8 flags; /* FDT_GPIO_... flags */ 81 }; 82 83 /* This tells us whether a fdt_gpio_state record is valid or not */ 84 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 85 86 /** 87 * Find the next numbered alias for a peripheral. This is used to enumerate 88 * all the peripherals of a certain type. 89 * 90 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 91 * this function will return a pointer to the node the alias points to, and 92 * then update *upto to 1. Next time you call this function, the next node 93 * will be returned. 94 * 95 * All nodes returned will match the compatible ID, as it is assumed that 96 * all peripherals use the same driver. 97 * 98 * @param blob FDT blob to use 99 * @param name Root name of alias to search for 100 * @param id Compatible ID to look for 101 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 102 */ 103 int fdtdec_next_alias(const void *blob, const char *name, 104 enum fdt_compat_id id, int *upto); 105 106 /** 107 * Find the next compatible node for a peripheral. 108 * 109 * Do the first call with node = 0. This function will return a pointer to 110 * the next compatible node. Next time you call this function, pass the 111 * value returned, and the next node will be provided. 112 * 113 * @param blob FDT blob to use 114 * @param node Start node for search 115 * @param id Compatible ID to look for (enum fdt_compat_id) 116 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 117 */ 118 int fdtdec_next_compatible(const void *blob, int node, 119 enum fdt_compat_id id); 120 121 /** 122 * Find the next compatible subnode for a peripheral. 123 * 124 * Do the first call with node set to the parent and depth = 0. This 125 * function will return the offset of the next compatible node. Next time 126 * you call this function, pass the node value returned last time, with 127 * depth unchanged, and the next node will be provided. 128 * 129 * @param blob FDT blob to use 130 * @param node Start node for search 131 * @param id Compatible ID to look for (enum fdt_compat_id) 132 * @param depthp Current depth (set to 0 before first call) 133 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 134 */ 135 int fdtdec_next_compatible_subnode(const void *blob, int node, 136 enum fdt_compat_id id, int *depthp); 137 138 /** 139 * Look up an address property in a node and return it as an address. 140 * The property must hold either one address with no trailing data or 141 * one address with a length. This is only tested on 32-bit machines. 142 * 143 * @param blob FDT blob 144 * @param node node to examine 145 * @param prop_name name of property to find 146 * @return address, if found, or FDT_ADDR_T_NONE if not 147 */ 148 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 149 const char *prop_name); 150 151 /** 152 * Look up a 32-bit integer property in a node and return it. The property 153 * must have at least 4 bytes of data. The value of the first cell is 154 * returned. 155 * 156 * @param blob FDT blob 157 * @param node node to examine 158 * @param prop_name name of property to find 159 * @param default_val default value to return if the property is not found 160 * @return integer value, if found, or default_val if not 161 */ 162 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 163 s32 default_val); 164 165 /** 166 * Checks whether a node is enabled. 167 * This looks for a 'status' property. If this exists, then returns 1 if 168 * the status is 'ok' and 0 otherwise. If there is no status property, 169 * it returns 1 on the assumption that anything mentioned should be enabled 170 * by default. 171 * 172 * @param blob FDT blob 173 * @param node node to examine 174 * @return integer value 0 (not enabled) or 1 (enabled) 175 */ 176 int fdtdec_get_is_enabled(const void *blob, int node); 177 178 /** 179 * Make sure we have a valid fdt available to control U-Boot. 180 * 181 * If not, a message is printed to the console if the console is ready. 182 * 183 * @return 0 if all ok, -1 if not 184 */ 185 int fdtdec_prepare_fdt(void); 186 187 /** 188 * Checks that we have a valid fdt available to control U-Boot. 189 190 * However, if not then for the moment nothing is done, since this function 191 * is called too early to panic(). 192 * 193 * @returns 0 194 */ 195 int fdtdec_check_fdt(void); 196 197 /** 198 * Find the nodes for a peripheral and return a list of them in the correct 199 * order. This is used to enumerate all the peripherals of a certain type. 200 * 201 * To use this, optionally set up a /aliases node with alias properties for 202 * a peripheral. For example, for usb you could have: 203 * 204 * aliases { 205 * usb0 = "/ehci@c5008000"; 206 * usb1 = "/ehci@c5000000"; 207 * }; 208 * 209 * Pass "usb" as the name to this function and will return a list of two 210 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 211 * 212 * All nodes returned will match the compatible ID, as it is assumed that 213 * all peripherals use the same driver. 214 * 215 * If no alias node is found, then the node list will be returned in the 216 * order found in the fdt. If the aliases mention a node which doesn't 217 * exist, then this will be ignored. If nodes are found with no aliases, 218 * they will be added in any order. 219 * 220 * If there is a gap in the aliases, then this function return a 0 node at 221 * that position. The return value will also count these gaps. 222 * 223 * This function checks node properties and will not return nodes which are 224 * marked disabled (status = "disabled"). 225 * 226 * @param blob FDT blob to use 227 * @param name Root name of alias to search for 228 * @param id Compatible ID to look for 229 * @param node_list Place to put list of found nodes 230 * @param maxcount Maximum number of nodes to find 231 * @return number of nodes found on success, FTD_ERR_... on error 232 */ 233 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 234 enum fdt_compat_id id, int *node_list, int maxcount); 235 236 /* 237 * This function is similar to fdtdec_find_aliases_for_id() except that it 238 * adds to the node_list that is passed in. Any 0 elements are considered 239 * available for allocation - others are considered already used and are 240 * skipped. 241 * 242 * You can use this by calling fdtdec_find_aliases_for_id() with an 243 * uninitialised array, then setting the elements that are returned to -1, 244 * say, then calling this function, perhaps with a different compat id. 245 * Any elements you get back that are >0 are new nodes added by the call 246 * to this function. 247 * 248 * Note that if you have some nodes with aliases and some without, you are 249 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with 250 * one compat_id may fill in positions for which you have aliases defined 251 * for another compat_id. When you later call *this* function with the second 252 * compat_id, the alias positions may already be used. A debug warning may 253 * be generated in this case, but it is safest to define aliases for all 254 * nodes when you care about the ordering. 255 */ 256 int fdtdec_add_aliases_for_id(const void *blob, const char *name, 257 enum fdt_compat_id id, int *node_list, int maxcount); 258 259 /* 260 * Get the name for a compatible ID 261 * 262 * @param id Compatible ID to look for 263 * @return compatible string for that id 264 */ 265 const char *fdtdec_get_compatible(enum fdt_compat_id id); 266 267 /* Look up a phandle and follow it to its node. Then return the offset 268 * of that node. 269 * 270 * @param blob FDT blob 271 * @param node node to examine 272 * @param prop_name name of property to find 273 * @return node offset if found, -ve error code on error 274 */ 275 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 276 277 /** 278 * Look up a property in a node and return its contents in an integer 279 * array of given length. The property must have at least enough data for 280 * the array (4*count bytes). It may have more, but this will be ignored. 281 * 282 * @param blob FDT blob 283 * @param node node to examine 284 * @param prop_name name of property to find 285 * @param array array to fill with data 286 * @param count number of array elements 287 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 288 * or -FDT_ERR_BADLAYOUT if not enough data 289 */ 290 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 291 u32 *array, int count); 292 293 /** 294 * Look up a property in a node and return a pointer to its contents as a 295 * unsigned int array of given length. The property must have at least enough 296 * data for the array ('count' cells). It may have more, but this will be 297 * ignored. The data is not copied. 298 * 299 * Note that you must access elements of the array with fdt32_to_cpu(), 300 * since the elements will be big endian even on a little endian machine. 301 * 302 * @param blob FDT blob 303 * @param node node to examine 304 * @param prop_name name of property to find 305 * @param count number of array elements 306 * @return pointer to array if found, or NULL if the property is not 307 * found or there is not enough data 308 */ 309 const u32 *fdtdec_locate_array(const void *blob, int node, 310 const char *prop_name, int count); 311 312 /** 313 * Look up a boolean property in a node and return it. 314 * 315 * A boolean properly is true if present in the device tree and false if not 316 * present, regardless of its value. 317 * 318 * @param blob FDT blob 319 * @param node node to examine 320 * @param prop_name name of property to find 321 * @return 1 if the properly is present; 0 if it isn't present 322 */ 323 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 324 325 /** 326 * Decode a single GPIOs from an FDT. 327 * 328 * If the property is not found, then the GPIO structure will still be 329 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 330 * provide optional GPIOs. 331 * 332 * @param blob FDT blob to use 333 * @param node Node to look at 334 * @param prop_name Node property name 335 * @param gpio gpio elements to fill from FDT 336 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 337 */ 338 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 339 struct fdt_gpio_state *gpio); 340 341 /** 342 * Set up a GPIO pin according to the provided gpio information. At present this 343 * just requests the GPIO. 344 * 345 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 346 * deal with optional GPIOs. 347 * 348 * @param gpio GPIO info to use for set up 349 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 350 */ 351 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 352 353 /* 354 * Look up a property in a node and return its contents in a byte 355 * array of given length. The property must have at least enough data for 356 * the array (count bytes). It may have more, but this will be ignored. 357 * 358 * @param blob FDT blob 359 * @param node node to examine 360 * @param prop_name name of property to find 361 * @param array array to fill with data 362 * @param count number of array elements 363 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found, 364 * or -FDT_ERR_BADLAYOUT if not enough data 365 */ 366 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name, 367 u8 *array, int count); 368 369 /** 370 * Look up a property in a node and return a pointer to its contents as a 371 * byte array of given length. The property must have at least enough data 372 * for the array (count bytes). It may have more, but this will be ignored. 373 * The data is not copied. 374 * 375 * @param blob FDT blob 376 * @param node node to examine 377 * @param prop_name name of property to find 378 * @param count number of array elements 379 * @return pointer to byte array if found, or NULL if the property is not 380 * found or there is not enough data 381 */ 382 const u8 *fdtdec_locate_byte_array(const void *blob, int node, 383 const char *prop_name, int count); 384