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 COMPAT_NVIDIA_TEGRA20_NAND, /* Tegra2 NAND controller */ 67 68 COMPAT_COUNT, 69 }; 70 71 /* GPIOs are numbered from 0 */ 72 enum { 73 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 74 75 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 76 }; 77 78 /* This is the state of a GPIO pin as defined by the fdt */ 79 struct fdt_gpio_state { 80 const char *name; /* name of the fdt property defining this */ 81 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 82 u8 flags; /* FDT_GPIO_... flags */ 83 }; 84 85 /* This tells us whether a fdt_gpio_state record is valid or not */ 86 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 87 88 /** 89 * Find the next numbered alias for a peripheral. This is used to enumerate 90 * all the peripherals of a certain type. 91 * 92 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 93 * this function will return a pointer to the node the alias points to, and 94 * then update *upto to 1. Next time you call this function, the next node 95 * will be returned. 96 * 97 * All nodes returned will match the compatible ID, as it is assumed that 98 * all peripherals use the same driver. 99 * 100 * @param blob FDT blob to use 101 * @param name Root name of alias to search for 102 * @param id Compatible ID to look for 103 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 104 */ 105 int fdtdec_next_alias(const void *blob, const char *name, 106 enum fdt_compat_id id, int *upto); 107 108 /** 109 * Find the next compatible node for a peripheral. 110 * 111 * Do the first call with node = 0. This function will return a pointer to 112 * the next compatible node. Next time you call this function, pass the 113 * value returned, and the next node will be provided. 114 * 115 * @param blob FDT blob to use 116 * @param node Start node for search 117 * @param id Compatible ID to look for (enum fdt_compat_id) 118 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 119 */ 120 int fdtdec_next_compatible(const void *blob, int node, 121 enum fdt_compat_id id); 122 123 /** 124 * Find the next compatible subnode for a peripheral. 125 * 126 * Do the first call with node set to the parent and depth = 0. This 127 * function will return the offset of the next compatible node. Next time 128 * you call this function, pass the node value returned last time, with 129 * depth unchanged, and the next node will be provided. 130 * 131 * @param blob FDT blob to use 132 * @param node Start node for search 133 * @param id Compatible ID to look for (enum fdt_compat_id) 134 * @param depthp Current depth (set to 0 before first call) 135 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 136 */ 137 int fdtdec_next_compatible_subnode(const void *blob, int node, 138 enum fdt_compat_id id, int *depthp); 139 140 /** 141 * Look up an address property in a node and return it as an address. 142 * The property must hold either one address with no trailing data or 143 * one address with a length. This is only tested on 32-bit machines. 144 * 145 * @param blob FDT blob 146 * @param node node to examine 147 * @param prop_name name of property to find 148 * @return address, if found, or FDT_ADDR_T_NONE if not 149 */ 150 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 151 const char *prop_name); 152 153 /** 154 * Look up a 32-bit integer property in a node and return it. The property 155 * must have at least 4 bytes of data. The value of the first cell is 156 * returned. 157 * 158 * @param blob FDT blob 159 * @param node node to examine 160 * @param prop_name name of property to find 161 * @param default_val default value to return if the property is not found 162 * @return integer value, if found, or default_val if not 163 */ 164 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 165 s32 default_val); 166 167 /** 168 * Checks whether a node is enabled. 169 * This looks for a 'status' property. If this exists, then returns 1 if 170 * the status is 'ok' and 0 otherwise. If there is no status property, 171 * it returns 1 on the assumption that anything mentioned should be enabled 172 * by default. 173 * 174 * @param blob FDT blob 175 * @param node node to examine 176 * @return integer value 0 (not enabled) or 1 (enabled) 177 */ 178 int fdtdec_get_is_enabled(const void *blob, int node); 179 180 /** 181 * Make sure we have a valid fdt available to control U-Boot. 182 * 183 * If not, a message is printed to the console if the console is ready. 184 * 185 * @return 0 if all ok, -1 if not 186 */ 187 int fdtdec_prepare_fdt(void); 188 189 /** 190 * Checks that we have a valid fdt available to control U-Boot. 191 192 * However, if not then for the moment nothing is done, since this function 193 * is called too early to panic(). 194 * 195 * @returns 0 196 */ 197 int fdtdec_check_fdt(void); 198 199 /** 200 * Find the nodes for a peripheral and return a list of them in the correct 201 * order. This is used to enumerate all the peripherals of a certain type. 202 * 203 * To use this, optionally set up a /aliases node with alias properties for 204 * a peripheral. For example, for usb you could have: 205 * 206 * aliases { 207 * usb0 = "/ehci@c5008000"; 208 * usb1 = "/ehci@c5000000"; 209 * }; 210 * 211 * Pass "usb" as the name to this function and will return a list of two 212 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 213 * 214 * All nodes returned will match the compatible ID, as it is assumed that 215 * all peripherals use the same driver. 216 * 217 * If no alias node is found, then the node list will be returned in the 218 * order found in the fdt. If the aliases mention a node which doesn't 219 * exist, then this will be ignored. If nodes are found with no aliases, 220 * they will be added in any order. 221 * 222 * If there is a gap in the aliases, then this function return a 0 node at 223 * that position. The return value will also count these gaps. 224 * 225 * This function checks node properties and will not return nodes which are 226 * marked disabled (status = "disabled"). 227 * 228 * @param blob FDT blob to use 229 * @param name Root name of alias to search for 230 * @param id Compatible ID to look for 231 * @param node_list Place to put list of found nodes 232 * @param maxcount Maximum number of nodes to find 233 * @return number of nodes found on success, FTD_ERR_... on error 234 */ 235 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 236 enum fdt_compat_id id, int *node_list, int maxcount); 237 238 /* 239 * This function is similar to fdtdec_find_aliases_for_id() except that it 240 * adds to the node_list that is passed in. Any 0 elements are considered 241 * available for allocation - others are considered already used and are 242 * skipped. 243 * 244 * You can use this by calling fdtdec_find_aliases_for_id() with an 245 * uninitialised array, then setting the elements that are returned to -1, 246 * say, then calling this function, perhaps with a different compat id. 247 * Any elements you get back that are >0 are new nodes added by the call 248 * to this function. 249 * 250 * Note that if you have some nodes with aliases and some without, you are 251 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with 252 * one compat_id may fill in positions for which you have aliases defined 253 * for another compat_id. When you later call *this* function with the second 254 * compat_id, the alias positions may already be used. A debug warning may 255 * be generated in this case, but it is safest to define aliases for all 256 * nodes when you care about the ordering. 257 */ 258 int fdtdec_add_aliases_for_id(const void *blob, const char *name, 259 enum fdt_compat_id id, int *node_list, int maxcount); 260 261 /* 262 * Get the name for a compatible ID 263 * 264 * @param id Compatible ID to look for 265 * @return compatible string for that id 266 */ 267 const char *fdtdec_get_compatible(enum fdt_compat_id id); 268 269 /* Look up a phandle and follow it to its node. Then return the offset 270 * of that node. 271 * 272 * @param blob FDT blob 273 * @param node node to examine 274 * @param prop_name name of property to find 275 * @return node offset if found, -ve error code on error 276 */ 277 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 278 279 /** 280 * Look up a property in a node and return its contents in an integer 281 * array of given length. The property must have at least enough data for 282 * the array (4*count bytes). It may have more, but this will be ignored. 283 * 284 * @param blob FDT blob 285 * @param node node to examine 286 * @param prop_name name of property to find 287 * @param array array to fill with data 288 * @param count number of array elements 289 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 290 * or -FDT_ERR_BADLAYOUT if not enough data 291 */ 292 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 293 u32 *array, int count); 294 295 /** 296 * Look up a property in a node and return a pointer to its contents as a 297 * unsigned int array of given length. The property must have at least enough 298 * data for the array ('count' cells). It may have more, but this will be 299 * ignored. The data is not copied. 300 * 301 * Note that you must access elements of the array with fdt32_to_cpu(), 302 * since the elements will be big endian even on a little endian machine. 303 * 304 * @param blob FDT blob 305 * @param node node to examine 306 * @param prop_name name of property to find 307 * @param count number of array elements 308 * @return pointer to array if found, or NULL if the property is not 309 * found or there is not enough data 310 */ 311 const u32 *fdtdec_locate_array(const void *blob, int node, 312 const char *prop_name, int count); 313 314 /** 315 * Look up a boolean property in a node and return it. 316 * 317 * A boolean properly is true if present in the device tree and false if not 318 * present, regardless of its value. 319 * 320 * @param blob FDT blob 321 * @param node node to examine 322 * @param prop_name name of property to find 323 * @return 1 if the properly is present; 0 if it isn't present 324 */ 325 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 326 327 /** 328 * Decode a single GPIOs from an FDT. 329 * 330 * If the property is not found, then the GPIO structure will still be 331 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 332 * provide optional GPIOs. 333 * 334 * @param blob FDT blob to use 335 * @param node Node to look at 336 * @param prop_name Node property name 337 * @param gpio gpio elements to fill from FDT 338 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 339 */ 340 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 341 struct fdt_gpio_state *gpio); 342 343 /** 344 * Set up a GPIO pin according to the provided gpio information. At present this 345 * just requests the GPIO. 346 * 347 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 348 * deal with optional GPIOs. 349 * 350 * @param gpio GPIO info to use for set up 351 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 352 */ 353 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 354 355 /* 356 * Look up a property in a node and return its contents in a byte 357 * array of given length. The property must have at least enough data for 358 * the array (count bytes). It may have more, but this will be ignored. 359 * 360 * @param blob FDT blob 361 * @param node node to examine 362 * @param prop_name name of property to find 363 * @param array array to fill with data 364 * @param count number of array elements 365 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found, 366 * or -FDT_ERR_BADLAYOUT if not enough data 367 */ 368 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name, 369 u8 *array, int count); 370 371 /** 372 * Look up a property in a node and return a pointer to its contents as a 373 * byte array of given length. The property must have at least enough data 374 * for the array (count bytes). It may have more, but this will be ignored. 375 * The data is not copied. 376 * 377 * @param blob FDT blob 378 * @param node node to examine 379 * @param prop_name name of property to find 380 * @param count number of array elements 381 * @return pointer to byte array if found, or NULL if the property is not 382 * found or there is not enough data 383 */ 384 const u8 *fdtdec_locate_byte_array(const void *blob, int node, 385 const char *prop_name, int count); 386