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 COMPAT_NVIDIA_TEGRA20_NAND, /* Tegra2 NAND controller */ 69 COMPAT_NVIDIA_TEGRA20_PWM, /* Tegra 2 PWM controller */ 70 71 COMPAT_COUNT, 72 }; 73 74 /* GPIOs are numbered from 0 */ 75 enum { 76 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 77 78 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 79 }; 80 81 /* This is the state of a GPIO pin as defined by the fdt */ 82 struct fdt_gpio_state { 83 const char *name; /* name of the fdt property defining this */ 84 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 85 u8 flags; /* FDT_GPIO_... flags */ 86 }; 87 88 /* This tells us whether a fdt_gpio_state record is valid or not */ 89 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 90 91 /** 92 * Find the next numbered alias for a peripheral. This is used to enumerate 93 * all the peripherals of a certain type. 94 * 95 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 96 * this function will return a pointer to the node the alias points to, and 97 * then update *upto to 1. Next time you call this function, the next node 98 * will be returned. 99 * 100 * All nodes returned will match the compatible ID, as it is assumed that 101 * all peripherals use the same driver. 102 * 103 * @param blob FDT blob to use 104 * @param name Root name of alias to search for 105 * @param id Compatible ID to look for 106 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 107 */ 108 int fdtdec_next_alias(const void *blob, const char *name, 109 enum fdt_compat_id id, int *upto); 110 111 /** 112 * Find the next compatible node for a peripheral. 113 * 114 * Do the first call with node = 0. This function will return a pointer to 115 * the next compatible node. Next time you call this function, pass the 116 * value returned, and the next node will be provided. 117 * 118 * @param blob FDT blob to use 119 * @param node Start node for search 120 * @param id Compatible ID to look for (enum fdt_compat_id) 121 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 122 */ 123 int fdtdec_next_compatible(const void *blob, int node, 124 enum fdt_compat_id id); 125 126 /** 127 * Find the next compatible subnode for a peripheral. 128 * 129 * Do the first call with node set to the parent and depth = 0. This 130 * function will return the offset of the next compatible node. Next time 131 * you call this function, pass the node value returned last time, with 132 * depth unchanged, and the next node will be provided. 133 * 134 * @param blob FDT blob to use 135 * @param node Start node for search 136 * @param id Compatible ID to look for (enum fdt_compat_id) 137 * @param depthp Current depth (set to 0 before first call) 138 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 139 */ 140 int fdtdec_next_compatible_subnode(const void *blob, int node, 141 enum fdt_compat_id id, int *depthp); 142 143 /** 144 * Look up an address property in a node and return it as an address. 145 * The property must hold either one address with no trailing data or 146 * one address with a length. This is only tested on 32-bit machines. 147 * 148 * @param blob FDT blob 149 * @param node node to examine 150 * @param prop_name name of property to find 151 * @return address, if found, or FDT_ADDR_T_NONE if not 152 */ 153 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 154 const char *prop_name); 155 156 /** 157 * Look up a 32-bit integer property in a node and return it. The property 158 * must have at least 4 bytes of data. The value of the first cell is 159 * returned. 160 * 161 * @param blob FDT blob 162 * @param node node to examine 163 * @param prop_name name of property to find 164 * @param default_val default value to return if the property is not found 165 * @return integer value, if found, or default_val if not 166 */ 167 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 168 s32 default_val); 169 170 /** 171 * Checks whether a node is enabled. 172 * This looks for a 'status' property. If this exists, then returns 1 if 173 * the status is 'ok' and 0 otherwise. If there is no status property, 174 * it returns 1 on the assumption that anything mentioned should be enabled 175 * by default. 176 * 177 * @param blob FDT blob 178 * @param node node to examine 179 * @return integer value 0 (not enabled) or 1 (enabled) 180 */ 181 int fdtdec_get_is_enabled(const void *blob, int node); 182 183 /** 184 * Make sure we have a valid fdt available to control U-Boot. 185 * 186 * If not, a message is printed to the console if the console is ready. 187 * 188 * @return 0 if all ok, -1 if not 189 */ 190 int fdtdec_prepare_fdt(void); 191 192 /** 193 * Checks that we have a valid fdt available to control U-Boot. 194 195 * However, if not then for the moment nothing is done, since this function 196 * is called too early to panic(). 197 * 198 * @returns 0 199 */ 200 int fdtdec_check_fdt(void); 201 202 /** 203 * Find the nodes for a peripheral and return a list of them in the correct 204 * order. This is used to enumerate all the peripherals of a certain type. 205 * 206 * To use this, optionally set up a /aliases node with alias properties for 207 * a peripheral. For example, for usb you could have: 208 * 209 * aliases { 210 * usb0 = "/ehci@c5008000"; 211 * usb1 = "/ehci@c5000000"; 212 * }; 213 * 214 * Pass "usb" as the name to this function and will return a list of two 215 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 216 * 217 * All nodes returned will match the compatible ID, as it is assumed that 218 * all peripherals use the same driver. 219 * 220 * If no alias node is found, then the node list will be returned in the 221 * order found in the fdt. If the aliases mention a node which doesn't 222 * exist, then this will be ignored. If nodes are found with no aliases, 223 * they will be added in any order. 224 * 225 * If there is a gap in the aliases, then this function return a 0 node at 226 * that position. The return value will also count these gaps. 227 * 228 * This function checks node properties and will not return nodes which are 229 * marked disabled (status = "disabled"). 230 * 231 * @param blob FDT blob to use 232 * @param name Root name of alias to search for 233 * @param id Compatible ID to look for 234 * @param node_list Place to put list of found nodes 235 * @param maxcount Maximum number of nodes to find 236 * @return number of nodes found on success, FTD_ERR_... on error 237 */ 238 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 239 enum fdt_compat_id id, int *node_list, int maxcount); 240 241 /* 242 * This function is similar to fdtdec_find_aliases_for_id() except that it 243 * adds to the node_list that is passed in. Any 0 elements are considered 244 * available for allocation - others are considered already used and are 245 * skipped. 246 * 247 * You can use this by calling fdtdec_find_aliases_for_id() with an 248 * uninitialised array, then setting the elements that are returned to -1, 249 * say, then calling this function, perhaps with a different compat id. 250 * Any elements you get back that are >0 are new nodes added by the call 251 * to this function. 252 * 253 * Note that if you have some nodes with aliases and some without, you are 254 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with 255 * one compat_id may fill in positions for which you have aliases defined 256 * for another compat_id. When you later call *this* function with the second 257 * compat_id, the alias positions may already be used. A debug warning may 258 * be generated in this case, but it is safest to define aliases for all 259 * nodes when you care about the ordering. 260 */ 261 int fdtdec_add_aliases_for_id(const void *blob, const char *name, 262 enum fdt_compat_id id, int *node_list, int maxcount); 263 264 /* 265 * Get the name for a compatible ID 266 * 267 * @param id Compatible ID to look for 268 * @return compatible string for that id 269 */ 270 const char *fdtdec_get_compatible(enum fdt_compat_id id); 271 272 /* Look up a phandle and follow it to its node. Then return the offset 273 * of that node. 274 * 275 * @param blob FDT blob 276 * @param node node to examine 277 * @param prop_name name of property to find 278 * @return node offset if found, -ve error code on error 279 */ 280 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 281 282 /** 283 * Look up a property in a node and return its contents in an integer 284 * array of given length. The property must have at least enough data for 285 * the array (4*count bytes). It may have more, but this will be ignored. 286 * 287 * @param blob FDT blob 288 * @param node node to examine 289 * @param prop_name name of property to find 290 * @param array array to fill with data 291 * @param count number of array elements 292 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 293 * or -FDT_ERR_BADLAYOUT if not enough data 294 */ 295 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 296 u32 *array, int count); 297 298 /** 299 * Look up a property in a node and return a pointer to its contents as a 300 * unsigned int array of given length. The property must have at least enough 301 * data for the array ('count' cells). It may have more, but this will be 302 * ignored. The data is not copied. 303 * 304 * Note that you must access elements of the array with fdt32_to_cpu(), 305 * since the elements will be big endian even on a little endian machine. 306 * 307 * @param blob FDT blob 308 * @param node node to examine 309 * @param prop_name name of property to find 310 * @param count number of array elements 311 * @return pointer to array if found, or NULL if the property is not 312 * found or there is not enough data 313 */ 314 const u32 *fdtdec_locate_array(const void *blob, int node, 315 const char *prop_name, int count); 316 317 /** 318 * Look up a boolean property in a node and return it. 319 * 320 * A boolean properly is true if present in the device tree and false if not 321 * present, regardless of its value. 322 * 323 * @param blob FDT blob 324 * @param node node to examine 325 * @param prop_name name of property to find 326 * @return 1 if the properly is present; 0 if it isn't present 327 */ 328 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 329 330 /** 331 * Decode a single GPIOs from an FDT. 332 * 333 * If the property is not found, then the GPIO structure will still be 334 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 335 * provide optional GPIOs. 336 * 337 * @param blob FDT blob to use 338 * @param node Node to look at 339 * @param prop_name Node property name 340 * @param gpio gpio elements to fill from FDT 341 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 342 */ 343 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 344 struct fdt_gpio_state *gpio); 345 346 /** 347 * Set up a GPIO pin according to the provided gpio information. At present this 348 * just requests the GPIO. 349 * 350 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 351 * deal with optional GPIOs. 352 * 353 * @param gpio GPIO info to use for set up 354 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 355 */ 356 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 357 358 /* 359 * Look up a property in a node and return its contents in a byte 360 * array of given length. The property must have at least enough data for 361 * the array (count bytes). It may have more, but this will be ignored. 362 * 363 * @param blob FDT blob 364 * @param node node to examine 365 * @param prop_name name of property to find 366 * @param array array to fill with data 367 * @param count number of array elements 368 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found, 369 * or -FDT_ERR_BADLAYOUT if not enough data 370 */ 371 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name, 372 u8 *array, int count); 373 374 /** 375 * Look up a property in a node and return a pointer to its contents as a 376 * byte array of given length. The property must have at least enough data 377 * for the array (count bytes). It may have more, but this will be ignored. 378 * The data is not copied. 379 * 380 * @param blob FDT blob 381 * @param node node to examine 382 * @param prop_name name of property to find 383 * @param count number of array elements 384 * @return pointer to byte array if found, or NULL if the property is not 385 * found or there is not enough data 386 */ 387 const u8 *fdtdec_locate_byte_array(const void *blob, int node, 388 const char *prop_name, int count); 389 #endif 390