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 COMPAT_NVIDIA_TEGRA20_DC, /* Tegra 2 Display controller */ 71 72 COMPAT_COUNT, 73 }; 74 75 /* GPIOs are numbered from 0 */ 76 enum { 77 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 78 79 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 80 }; 81 82 /* This is the state of a GPIO pin as defined by the fdt */ 83 struct fdt_gpio_state { 84 const char *name; /* name of the fdt property defining this */ 85 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 86 u8 flags; /* FDT_GPIO_... flags */ 87 }; 88 89 /* This tells us whether a fdt_gpio_state record is valid or not */ 90 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 91 92 /** 93 * Find the next numbered alias for a peripheral. This is used to enumerate 94 * all the peripherals of a certain type. 95 * 96 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 97 * this function will return a pointer to the node the alias points to, and 98 * then update *upto to 1. Next time you call this function, the next node 99 * will be returned. 100 * 101 * All nodes returned will match the compatible ID, as it is assumed that 102 * all peripherals use the same driver. 103 * 104 * @param blob FDT blob to use 105 * @param name Root name of alias to search for 106 * @param id Compatible ID to look for 107 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 108 */ 109 int fdtdec_next_alias(const void *blob, const char *name, 110 enum fdt_compat_id id, int *upto); 111 112 /** 113 * Find the next compatible node for a peripheral. 114 * 115 * Do the first call with node = 0. This function will return a pointer to 116 * the next compatible node. Next time you call this function, pass the 117 * value returned, and the next node will be provided. 118 * 119 * @param blob FDT blob to use 120 * @param node Start node for search 121 * @param id Compatible ID to look for (enum fdt_compat_id) 122 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 123 */ 124 int fdtdec_next_compatible(const void *blob, int node, 125 enum fdt_compat_id id); 126 127 /** 128 * Find the next compatible subnode for a peripheral. 129 * 130 * Do the first call with node set to the parent and depth = 0. This 131 * function will return the offset of the next compatible node. Next time 132 * you call this function, pass the node value returned last time, with 133 * depth unchanged, and the next node will be provided. 134 * 135 * @param blob FDT blob to use 136 * @param node Start node for search 137 * @param id Compatible ID to look for (enum fdt_compat_id) 138 * @param depthp Current depth (set to 0 before first call) 139 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 140 */ 141 int fdtdec_next_compatible_subnode(const void *blob, int node, 142 enum fdt_compat_id id, int *depthp); 143 144 /** 145 * Look up an address property in a node and return it as an address. 146 * The property must hold either one address with no trailing data or 147 * one address with a length. This is only tested on 32-bit machines. 148 * 149 * @param blob FDT blob 150 * @param node node to examine 151 * @param prop_name name of property to find 152 * @return address, if found, or FDT_ADDR_T_NONE if not 153 */ 154 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 155 const char *prop_name); 156 157 /** 158 * Look up a 32-bit integer property in a node and return it. The property 159 * must have at least 4 bytes of data. The value of the first cell is 160 * returned. 161 * 162 * @param blob FDT blob 163 * @param node node to examine 164 * @param prop_name name of property to find 165 * @param default_val default value to return if the property is not found 166 * @return integer value, if found, or default_val if not 167 */ 168 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 169 s32 default_val); 170 171 /** 172 * Checks whether a node is enabled. 173 * This looks for a 'status' property. If this exists, then returns 1 if 174 * the status is 'ok' and 0 otherwise. If there is no status property, 175 * it returns 1 on the assumption that anything mentioned should be enabled 176 * by default. 177 * 178 * @param blob FDT blob 179 * @param node node to examine 180 * @return integer value 0 (not enabled) or 1 (enabled) 181 */ 182 int fdtdec_get_is_enabled(const void *blob, int node); 183 184 /** 185 * Make sure we have a valid fdt available to control U-Boot. 186 * 187 * If not, a message is printed to the console if the console is ready. 188 * 189 * @return 0 if all ok, -1 if not 190 */ 191 int fdtdec_prepare_fdt(void); 192 193 /** 194 * Checks that we have a valid fdt available to control U-Boot. 195 196 * However, if not then for the moment nothing is done, since this function 197 * is called too early to panic(). 198 * 199 * @returns 0 200 */ 201 int fdtdec_check_fdt(void); 202 203 /** 204 * Find the nodes for a peripheral and return a list of them in the correct 205 * order. This is used to enumerate all the peripherals of a certain type. 206 * 207 * To use this, optionally set up a /aliases node with alias properties for 208 * a peripheral. For example, for usb you could have: 209 * 210 * aliases { 211 * usb0 = "/ehci@c5008000"; 212 * usb1 = "/ehci@c5000000"; 213 * }; 214 * 215 * Pass "usb" as the name to this function and will return a list of two 216 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 217 * 218 * All nodes returned will match the compatible ID, as it is assumed that 219 * all peripherals use the same driver. 220 * 221 * If no alias node is found, then the node list will be returned in the 222 * order found in the fdt. If the aliases mention a node which doesn't 223 * exist, then this will be ignored. If nodes are found with no aliases, 224 * they will be added in any order. 225 * 226 * If there is a gap in the aliases, then this function return a 0 node at 227 * that position. The return value will also count these gaps. 228 * 229 * This function checks node properties and will not return nodes which are 230 * marked disabled (status = "disabled"). 231 * 232 * @param blob FDT blob to use 233 * @param name Root name of alias to search for 234 * @param id Compatible ID to look for 235 * @param node_list Place to put list of found nodes 236 * @param maxcount Maximum number of nodes to find 237 * @return number of nodes found on success, FTD_ERR_... on error 238 */ 239 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 240 enum fdt_compat_id id, int *node_list, int maxcount); 241 242 /* 243 * This function is similar to fdtdec_find_aliases_for_id() except that it 244 * adds to the node_list that is passed in. Any 0 elements are considered 245 * available for allocation - others are considered already used and are 246 * skipped. 247 * 248 * You can use this by calling fdtdec_find_aliases_for_id() with an 249 * uninitialised array, then setting the elements that are returned to -1, 250 * say, then calling this function, perhaps with a different compat id. 251 * Any elements you get back that are >0 are new nodes added by the call 252 * to this function. 253 * 254 * Note that if you have some nodes with aliases and some without, you are 255 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with 256 * one compat_id may fill in positions for which you have aliases defined 257 * for another compat_id. When you later call *this* function with the second 258 * compat_id, the alias positions may already be used. A debug warning may 259 * be generated in this case, but it is safest to define aliases for all 260 * nodes when you care about the ordering. 261 */ 262 int fdtdec_add_aliases_for_id(const void *blob, const char *name, 263 enum fdt_compat_id id, int *node_list, int maxcount); 264 265 /* 266 * Get the name for a compatible ID 267 * 268 * @param id Compatible ID to look for 269 * @return compatible string for that id 270 */ 271 const char *fdtdec_get_compatible(enum fdt_compat_id id); 272 273 /* Look up a phandle and follow it to its node. Then return the offset 274 * of that node. 275 * 276 * @param blob FDT blob 277 * @param node node to examine 278 * @param prop_name name of property to find 279 * @return node offset if found, -ve error code on error 280 */ 281 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 282 283 /** 284 * Look up a property in a node and return its contents in an integer 285 * array of given length. The property must have at least enough data for 286 * the array (4*count bytes). It may have more, but this will be ignored. 287 * 288 * @param blob FDT blob 289 * @param node node to examine 290 * @param prop_name name of property to find 291 * @param array array to fill with data 292 * @param count number of array elements 293 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 294 * or -FDT_ERR_BADLAYOUT if not enough data 295 */ 296 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 297 u32 *array, int count); 298 299 /** 300 * Look up a property in a node and return a pointer to its contents as a 301 * unsigned int array of given length. The property must have at least enough 302 * data for the array ('count' cells). It may have more, but this will be 303 * ignored. The data is not copied. 304 * 305 * Note that you must access elements of the array with fdt32_to_cpu(), 306 * since the elements will be big endian even on a little endian machine. 307 * 308 * @param blob FDT blob 309 * @param node node to examine 310 * @param prop_name name of property to find 311 * @param count number of array elements 312 * @return pointer to array if found, or NULL if the property is not 313 * found or there is not enough data 314 */ 315 const u32 *fdtdec_locate_array(const void *blob, int node, 316 const char *prop_name, int count); 317 318 /** 319 * Look up a boolean property in a node and return it. 320 * 321 * A boolean properly is true if present in the device tree and false if not 322 * present, regardless of its value. 323 * 324 * @param blob FDT blob 325 * @param node node to examine 326 * @param prop_name name of property to find 327 * @return 1 if the properly is present; 0 if it isn't present 328 */ 329 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 330 331 /** 332 * Decode a single GPIOs from an FDT. 333 * 334 * If the property is not found, then the GPIO structure will still be 335 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 336 * provide optional GPIOs. 337 * 338 * @param blob FDT blob to use 339 * @param node Node to look at 340 * @param prop_name Node property name 341 * @param gpio gpio elements to fill from FDT 342 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 343 */ 344 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 345 struct fdt_gpio_state *gpio); 346 347 /** 348 * Set up a GPIO pin according to the provided gpio information. At present this 349 * just requests the GPIO. 350 * 351 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 352 * deal with optional GPIOs. 353 * 354 * @param gpio GPIO info to use for set up 355 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 356 */ 357 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 358 359 /* 360 * Look up a property in a node and return its contents in a byte 361 * array of given length. The property must have at least enough data for 362 * the array (count bytes). It may have more, but this will be ignored. 363 * 364 * @param blob FDT blob 365 * @param node node to examine 366 * @param prop_name name of property to find 367 * @param array array to fill with data 368 * @param count number of array elements 369 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found, 370 * or -FDT_ERR_BADLAYOUT if not enough data 371 */ 372 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name, 373 u8 *array, int count); 374 375 /** 376 * Look up a property in a node and return a pointer to its contents as a 377 * byte array of given length. The property must have at least enough data 378 * for the array (count bytes). It may have more, but this will be ignored. 379 * The data is not copied. 380 * 381 * @param blob FDT blob 382 * @param node node to examine 383 * @param prop_name name of property to find 384 * @param count number of array elements 385 * @return pointer to byte array if found, or NULL if the property is not 386 * found or there is not enough data 387 */ 388 const u8 *fdtdec_locate_byte_array(const void *blob, int node, 389 const char *prop_name, int count); 390 #endif 391