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, /* Tegra2 USB port */ 61 COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra2 i2c */ 62 COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra2 dvc (really just i2c) */ 63 64 COMPAT_COUNT, 65 }; 66 67 /* GPIOs are numbered from 0 */ 68 enum { 69 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 70 71 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 72 }; 73 74 /* This is the state of a GPIO pin as defined by the fdt */ 75 struct fdt_gpio_state { 76 const char *name; /* name of the fdt property defining this */ 77 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 78 u8 flags; /* FDT_GPIO_... flags */ 79 }; 80 81 /* This tells us whether a fdt_gpio_state record is valid or not */ 82 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 83 84 /** 85 * Find the next numbered alias for a peripheral. This is used to enumerate 86 * all the peripherals of a certain type. 87 * 88 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 89 * this function will return a pointer to the node the alias points to, and 90 * then update *upto to 1. Next time you call this function, the next node 91 * will be returned. 92 * 93 * All nodes returned will match the compatible ID, as it is assumed that 94 * all peripherals use the same driver. 95 * 96 * @param blob FDT blob to use 97 * @param name Root name of alias to search for 98 * @param id Compatible ID to look for 99 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 100 */ 101 int fdtdec_next_alias(const void *blob, const char *name, 102 enum fdt_compat_id id, int *upto); 103 104 /** 105 * Find the next compatible node for a peripheral. 106 * 107 * Do the first call with node = 0. This function will return a pointer to 108 * the next compatible node. Next time you call this function, pass the 109 * value returned, and the next node will be provided. 110 * 111 * @param blob FDT blob to use 112 * @param node Start node for search 113 * @param id Compatible ID to look for (enum fdt_compat_id) 114 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 115 */ 116 int fdtdec_next_compatible(const void *blob, int node, 117 enum fdt_compat_id id); 118 119 /** 120 * Look up an address property in a node and return it as an address. 121 * The property must hold either one address with no trailing data or 122 * one address with a length. This is only tested on 32-bit machines. 123 * 124 * @param blob FDT blob 125 * @param node node to examine 126 * @param prop_name name of property to find 127 * @return address, if found, or FDT_ADDR_T_NONE if not 128 */ 129 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 130 const char *prop_name); 131 132 /** 133 * Look up a 32-bit integer property in a node and return it. The property 134 * must have at least 4 bytes of data. The value of the first cell is 135 * returned. 136 * 137 * @param blob FDT blob 138 * @param node node to examine 139 * @param prop_name name of property to find 140 * @param default_val default value to return if the property is not found 141 * @return integer value, if found, or default_val if not 142 */ 143 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 144 s32 default_val); 145 146 /** 147 * Checks whether a node is enabled. 148 * This looks for a 'status' property. If this exists, then returns 1 if 149 * the status is 'ok' and 0 otherwise. If there is no status property, 150 * it returns 1 on the assumption that anything mentioned should be enabled 151 * by default. 152 * 153 * @param blob FDT blob 154 * @param node node to examine 155 * @return integer value 0 (not enabled) or 1 (enabled) 156 */ 157 int fdtdec_get_is_enabled(const void *blob, int node); 158 159 /** 160 * Make sure we have a valid fdt available to control U-Boot. 161 * 162 * If not, a message is printed to the console if the console is ready. 163 * 164 * @return 0 if all ok, -1 if not 165 */ 166 int fdtdec_prepare_fdt(void); 167 168 /** 169 * Checks that we have a valid fdt available to control U-Boot. 170 171 * However, if not then for the moment nothing is done, since this function 172 * is called too early to panic(). 173 * 174 * @returns 0 175 */ 176 int fdtdec_check_fdt(void); 177 178 /** 179 * Find the nodes for a peripheral and return a list of them in the correct 180 * order. This is used to enumerate all the peripherals of a certain type. 181 * 182 * To use this, optionally set up a /aliases node with alias properties for 183 * a peripheral. For example, for usb you could have: 184 * 185 * aliases { 186 * usb0 = "/ehci@c5008000"; 187 * usb1 = "/ehci@c5000000"; 188 * }; 189 * 190 * Pass "usb" as the name to this function and will return a list of two 191 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 192 * 193 * All nodes returned will match the compatible ID, as it is assumed that 194 * all peripherals use the same driver. 195 * 196 * If no alias node is found, then the node list will be returned in the 197 * order found in the fdt. If the aliases mention a node which doesn't 198 * exist, then this will be ignored. If nodes are found with no aliases, 199 * they will be added in any order. 200 * 201 * If there is a gap in the aliases, then this function return a 0 node at 202 * that position. The return value will also count these gaps. 203 * 204 * This function checks node properties and will not return nodes which are 205 * marked disabled (status = "disabled"). 206 * 207 * @param blob FDT blob to use 208 * @param name Root name of alias to search for 209 * @param id Compatible ID to look for 210 * @param node_list Place to put list of found nodes 211 * @param maxcount Maximum number of nodes to find 212 * @return number of nodes found on success, FTD_ERR_... on error 213 */ 214 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 215 enum fdt_compat_id id, int *node_list, int maxcount); 216 217 /* 218 * This function is similar to fdtdec_find_aliases_for_id() except that it 219 * adds to the node_list that is passed in. Any 0 elements are considered 220 * available for allocation - others are considered already used and are 221 * skipped. 222 * 223 * You can use this by calling fdtdec_find_aliases_for_id() with an 224 * uninitialised array, then setting the elements that are returned to -1, 225 * say, then calling this function, perhaps with a different compat id. 226 * Any elements you get back that are >0 are new nodes added by the call 227 * to this function. 228 * 229 * Note that if you have some nodes with aliases and some without, you are 230 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with 231 * one compat_id may fill in positions for which you have aliases defined 232 * for another compat_id. When you later call *this* function with the second 233 * compat_id, the alias positions may already be used. A debug warning may 234 * be generated in this case, but it is safest to define aliases for all 235 * nodes when you care about the ordering. 236 */ 237 int fdtdec_add_aliases_for_id(const void *blob, const char *name, 238 enum fdt_compat_id id, int *node_list, int maxcount); 239 240 /* 241 * Get the name for a compatible ID 242 * 243 * @param id Compatible ID to look for 244 * @return compatible string for that id 245 */ 246 const char *fdtdec_get_compatible(enum fdt_compat_id id); 247 248 /* Look up a phandle and follow it to its node. Then return the offset 249 * of that node. 250 * 251 * @param blob FDT blob 252 * @param node node to examine 253 * @param prop_name name of property to find 254 * @return node offset if found, -ve error code on error 255 */ 256 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 257 258 /** 259 * Look up a property in a node and return its contents in an integer 260 * array of given length. The property must have at least enough data for 261 * the array (4*count bytes). It may have more, but this will be ignored. 262 * 263 * @param blob FDT blob 264 * @param node node to examine 265 * @param prop_name name of property to find 266 * @param array array to fill with data 267 * @param count number of array elements 268 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 269 * or -FDT_ERR_BADLAYOUT if not enough data 270 */ 271 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 272 u32 *array, int count); 273 274 /** 275 * Look up a boolean property in a node and return it. 276 * 277 * A boolean properly is true if present in the device tree and false if not 278 * present, regardless of its value. 279 * 280 * @param blob FDT blob 281 * @param node node to examine 282 * @param prop_name name of property to find 283 * @return 1 if the properly is present; 0 if it isn't present 284 */ 285 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 286 287 /** 288 * Decode a single GPIOs from an FDT. 289 * 290 * If the property is not found, then the GPIO structure will still be 291 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 292 * provide optional GPIOs. 293 * 294 * @param blob FDT blob to use 295 * @param node Node to look at 296 * @param prop_name Node property name 297 * @param gpio gpio elements to fill from FDT 298 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 299 */ 300 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 301 struct fdt_gpio_state *gpio); 302 303 /** 304 * Set up a GPIO pin according to the provided gpio information. At present this 305 * just requests the GPIO. 306 * 307 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 308 * deal with optional GPIOs. 309 * 310 * @param gpio GPIO info to use for set up 311 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 312 */ 313 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 314