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