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