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