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 #ifndef __fdtdec_h 23 #define __fdtdec_h 24 25 /* 26 * This file contains convenience functions for decoding useful and 27 * enlightening information from FDTs. It is intended to be used by device 28 * drivers and board-specific code within U-Boot. It aims to reduce the 29 * amount of FDT munging required within U-Boot itself, so that driver code 30 * changes to support FDT are minimized. 31 */ 32 33 #include <libfdt.h> 34 35 /* 36 * A typedef for a physical address. Note that fdt data is always big 37 * endian even on a litle endian machine. 38 */ 39 #ifdef CONFIG_PHYS_64BIT 40 typedef u64 fdt_addr_t; 41 #define FDT_ADDR_T_NONE (-1ULL) 42 #define fdt_addr_to_cpu(reg) be64_to_cpu(reg) 43 #else 44 typedef u32 fdt_addr_t; 45 #define FDT_ADDR_T_NONE (-1U) 46 #define fdt_addr_to_cpu(reg) be32_to_cpu(reg) 47 #endif 48 49 /* Information obtained about memory from the FDT */ 50 struct fdt_memory { 51 fdt_addr_t start; 52 fdt_addr_t end; 53 }; 54 55 /** 56 * Compat types that we know about and for which we might have drivers. 57 * Each is named COMPAT_<dir>_<filename> where <dir> is the directory 58 * within drivers. 59 */ 60 enum fdt_compat_id { 61 COMPAT_UNKNOWN, 62 COMPAT_NVIDIA_TEGRA20_USB, /* Tegra20 USB port */ 63 COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra20 i2c */ 64 COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra20 dvc (really just i2c) */ 65 COMPAT_NVIDIA_TEGRA20_EMC, /* Tegra20 memory controller */ 66 COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */ 67 COMPAT_NVIDIA_TEGRA20_KBC, /* Tegra20 Keyboard */ 68 69 COMPAT_COUNT, 70 }; 71 72 /* GPIOs are numbered from 0 */ 73 enum { 74 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 75 76 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 77 }; 78 79 /* This is the state of a GPIO pin as defined by the fdt */ 80 struct fdt_gpio_state { 81 const char *name; /* name of the fdt property defining this */ 82 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 83 u8 flags; /* FDT_GPIO_... flags */ 84 }; 85 86 /* This tells us whether a fdt_gpio_state record is valid or not */ 87 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 88 89 /** 90 * Find the next numbered alias for a peripheral. This is used to enumerate 91 * all the peripherals of a certain type. 92 * 93 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 94 * this function will return a pointer to the node the alias points to, and 95 * then update *upto to 1. Next time you call this function, the next node 96 * will be returned. 97 * 98 * All nodes returned will match the compatible ID, as it is assumed that 99 * all peripherals use the same driver. 100 * 101 * @param blob FDT blob to use 102 * @param name Root name of alias to search for 103 * @param id Compatible ID to look for 104 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 105 */ 106 int fdtdec_next_alias(const void *blob, const char *name, 107 enum fdt_compat_id id, int *upto); 108 109 /** 110 * Find the next compatible node for a peripheral. 111 * 112 * Do the first call with node = 0. This function will return a pointer to 113 * the next compatible node. Next time you call this function, pass the 114 * value returned, and the next node will be provided. 115 * 116 * @param blob FDT blob to use 117 * @param node Start node for search 118 * @param id Compatible ID to look for (enum fdt_compat_id) 119 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 120 */ 121 int fdtdec_next_compatible(const void *blob, int node, 122 enum fdt_compat_id id); 123 124 /** 125 * Find the next compatible subnode for a peripheral. 126 * 127 * Do the first call with node set to the parent and depth = 0. This 128 * function will return the offset of the next compatible node. Next time 129 * you call this function, pass the node value returned last time, with 130 * depth unchanged, and the next node will be provided. 131 * 132 * @param blob FDT blob to use 133 * @param node Start node for search 134 * @param id Compatible ID to look for (enum fdt_compat_id) 135 * @param depthp Current depth (set to 0 before first call) 136 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 137 */ 138 int fdtdec_next_compatible_subnode(const void *blob, int node, 139 enum fdt_compat_id id, int *depthp); 140 141 /** 142 * Look up an address property in a node and return it as an address. 143 * The property must hold either one address with no trailing data or 144 * one address with a length. This is only tested on 32-bit machines. 145 * 146 * @param blob FDT blob 147 * @param node node to examine 148 * @param prop_name name of property to find 149 * @return address, if found, or FDT_ADDR_T_NONE if not 150 */ 151 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 152 const char *prop_name); 153 154 /** 155 * Look up a 32-bit integer property in a node and return it. The property 156 * must have at least 4 bytes of data. The value of the first cell is 157 * returned. 158 * 159 * @param blob FDT blob 160 * @param node node to examine 161 * @param prop_name name of property to find 162 * @param default_val default value to return if the property is not found 163 * @return integer value, if found, or default_val if not 164 */ 165 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 166 s32 default_val); 167 168 /** 169 * Checks whether a node is enabled. 170 * This looks for a 'status' property. If this exists, then returns 1 if 171 * the status is 'ok' and 0 otherwise. If there is no status property, 172 * it returns 1 on the assumption that anything mentioned should be enabled 173 * by default. 174 * 175 * @param blob FDT blob 176 * @param node node to examine 177 * @return integer value 0 (not enabled) or 1 (enabled) 178 */ 179 int fdtdec_get_is_enabled(const void *blob, int node); 180 181 /** 182 * Make sure we have a valid fdt available to control U-Boot. 183 * 184 * If not, a message is printed to the console if the console is ready. 185 * 186 * @return 0 if all ok, -1 if not 187 */ 188 int fdtdec_prepare_fdt(void); 189 190 /** 191 * Checks that we have a valid fdt available to control U-Boot. 192 193 * However, if not then for the moment nothing is done, since this function 194 * is called too early to panic(). 195 * 196 * @returns 0 197 */ 198 int fdtdec_check_fdt(void); 199 200 /** 201 * Find the nodes for a peripheral and return a list of them in the correct 202 * order. This is used to enumerate all the peripherals of a certain type. 203 * 204 * To use this, optionally set up a /aliases node with alias properties for 205 * a peripheral. For example, for usb you could have: 206 * 207 * aliases { 208 * usb0 = "/ehci@c5008000"; 209 * usb1 = "/ehci@c5000000"; 210 * }; 211 * 212 * Pass "usb" as the name to this function and will return a list of two 213 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 214 * 215 * All nodes returned will match the compatible ID, as it is assumed that 216 * all peripherals use the same driver. 217 * 218 * If no alias node is found, then the node list will be returned in the 219 * order found in the fdt. If the aliases mention a node which doesn't 220 * exist, then this will be ignored. If nodes are found with no aliases, 221 * they will be added in any order. 222 * 223 * If there is a gap in the aliases, then this function return a 0 node at 224 * that position. The return value will also count these gaps. 225 * 226 * This function checks node properties and will not return nodes which are 227 * marked disabled (status = "disabled"). 228 * 229 * @param blob FDT blob to use 230 * @param name Root name of alias to search for 231 * @param id Compatible ID to look for 232 * @param node_list Place to put list of found nodes 233 * @param maxcount Maximum number of nodes to find 234 * @return number of nodes found on success, FTD_ERR_... on error 235 */ 236 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 237 enum fdt_compat_id id, int *node_list, int maxcount); 238 239 /* 240 * This function is similar to fdtdec_find_aliases_for_id() except that it 241 * adds to the node_list that is passed in. Any 0 elements are considered 242 * available for allocation - others are considered already used and are 243 * skipped. 244 * 245 * You can use this by calling fdtdec_find_aliases_for_id() with an 246 * uninitialised array, then setting the elements that are returned to -1, 247 * say, then calling this function, perhaps with a different compat id. 248 * Any elements you get back that are >0 are new nodes added by the call 249 * to this function. 250 * 251 * Note that if you have some nodes with aliases and some without, you are 252 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with 253 * one compat_id may fill in positions for which you have aliases defined 254 * for another compat_id. When you later call *this* function with the second 255 * compat_id, the alias positions may already be used. A debug warning may 256 * be generated in this case, but it is safest to define aliases for all 257 * nodes when you care about the ordering. 258 */ 259 int fdtdec_add_aliases_for_id(const void *blob, const char *name, 260 enum fdt_compat_id id, int *node_list, int maxcount); 261 262 /* 263 * Get the name for a compatible ID 264 * 265 * @param id Compatible ID to look for 266 * @return compatible string for that id 267 */ 268 const char *fdtdec_get_compatible(enum fdt_compat_id id); 269 270 /* Look up a phandle and follow it to its node. Then return the offset 271 * of that node. 272 * 273 * @param blob FDT blob 274 * @param node node to examine 275 * @param prop_name name of property to find 276 * @return node offset if found, -ve error code on error 277 */ 278 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 279 280 /** 281 * Look up a property in a node and return its contents in an integer 282 * array of given length. The property must have at least enough data for 283 * the array (4*count bytes). It may have more, but this will be ignored. 284 * 285 * @param blob FDT blob 286 * @param node node to examine 287 * @param prop_name name of property to find 288 * @param array array to fill with data 289 * @param count number of array elements 290 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 291 * or -FDT_ERR_BADLAYOUT if not enough data 292 */ 293 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 294 u32 *array, int count); 295 296 /** 297 * Look up a property in a node and return a pointer to its contents as a 298 * unsigned int array of given length. The property must have at least enough 299 * data for the array ('count' cells). It may have more, but this will be 300 * ignored. The data is not copied. 301 * 302 * Note that you must access elements of the array with fdt32_to_cpu(), 303 * since the elements will be big endian even on a little endian machine. 304 * 305 * @param blob FDT blob 306 * @param node node to examine 307 * @param prop_name name of property to find 308 * @param count number of array elements 309 * @return pointer to array if found, or NULL if the property is not 310 * found or there is not enough data 311 */ 312 const u32 *fdtdec_locate_array(const void *blob, int node, 313 const char *prop_name, int count); 314 315 /** 316 * Look up a boolean property in a node and return it. 317 * 318 * A boolean properly is true if present in the device tree and false if not 319 * present, regardless of its value. 320 * 321 * @param blob FDT blob 322 * @param node node to examine 323 * @param prop_name name of property to find 324 * @return 1 if the properly is present; 0 if it isn't present 325 */ 326 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 327 328 /** 329 * Decode a single GPIOs from an FDT. 330 * 331 * If the property is not found, then the GPIO structure will still be 332 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 333 * provide optional GPIOs. 334 * 335 * @param blob FDT blob to use 336 * @param node Node to look at 337 * @param prop_name Node property name 338 * @param gpio gpio elements to fill from FDT 339 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 340 */ 341 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 342 struct fdt_gpio_state *gpio); 343 344 /** 345 * Set up a GPIO pin according to the provided gpio information. At present this 346 * just requests the GPIO. 347 * 348 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 349 * deal with optional GPIOs. 350 * 351 * @param gpio GPIO info to use for set up 352 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 353 */ 354 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 355 356 /* 357 * Look up a property in a node and return its contents in a byte 358 * array of given length. The property must have at least enough data for 359 * the array (count bytes). It may have more, but this will be ignored. 360 * 361 * @param blob FDT blob 362 * @param node node to examine 363 * @param prop_name name of property to find 364 * @param array array to fill with data 365 * @param count number of array elements 366 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found, 367 * or -FDT_ERR_BADLAYOUT if not enough data 368 */ 369 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name, 370 u8 *array, int count); 371 372 /** 373 * Look up a property in a node and return a pointer to its contents as a 374 * byte array of given length. The property must have at least enough data 375 * for the array (count bytes). It may have more, but this will be ignored. 376 * The data is not copied. 377 * 378 * @param blob FDT blob 379 * @param node node to examine 380 * @param prop_name name of property to find 381 * @param count number of array elements 382 * @return pointer to byte array if found, or NULL if the property is not 383 * found or there is not enough data 384 */ 385 const u8 *fdtdec_locate_byte_array(const void *blob, int node, 386 const char *prop_name, int count); 387 #endif 388