/* * Copyright (c) 2011 The Chromium OS Authors. * See file CREDITS for list of people who contributed to this * project. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ /* * This file contains convenience functions for decoding useful and * enlightening information from FDTs. It is intended to be used by device * drivers and board-specific code within U-Boot. It aims to reduce the * amount of FDT munging required within U-Boot itself, so that driver code * changes to support FDT are minimized. */ #include <libfdt.h> /* * A typedef for a physical address. Note that fdt data is always big * endian even on a litle endian machine. */ #ifdef CONFIG_PHYS_64BIT typedef u64 fdt_addr_t; #define FDT_ADDR_T_NONE (-1ULL) #define fdt_addr_to_cpu(reg) be64_to_cpu(reg) #else typedef u32 fdt_addr_t; #define FDT_ADDR_T_NONE (-1U) #define fdt_addr_to_cpu(reg) be32_to_cpu(reg) #endif /* Information obtained about memory from the FDT */ struct fdt_memory { fdt_addr_t start; fdt_addr_t end; }; /** * Compat types that we know about and for which we might have drivers. * Each is named COMPAT_<dir>_<filename> where <dir> is the directory * within drivers. */ enum fdt_compat_id { COMPAT_UNKNOWN, COMPAT_NVIDIA_TEGRA20_USB, /* Tegra2 USB port */ COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra2 i2c */ COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra2 dvc (really just i2c) */ COMPAT_COUNT, }; /* GPIOs are numbered from 0 */ enum { FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ }; /* This is the state of a GPIO pin as defined by the fdt */ struct fdt_gpio_state { const char *name; /* name of the fdt property defining this */ uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ u8 flags; /* FDT_GPIO_... flags */ }; /* This tells us whether a fdt_gpio_state record is valid or not */ #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) /** * Find the next numbered alias for a peripheral. This is used to enumerate * all the peripherals of a certain type. * * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then * this function will return a pointer to the node the alias points to, and * then update *upto to 1. Next time you call this function, the next node * will be returned. * * All nodes returned will match the compatible ID, as it is assumed that * all peripherals use the same driver. * * @param blob FDT blob to use * @param name Root name of alias to search for * @param id Compatible ID to look for * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more */ int fdtdec_next_alias(const void *blob, const char *name, enum fdt_compat_id id, int *upto); /** * Find the next compatible node for a peripheral. * * Do the first call with node = 0. This function will return a pointer to * the next compatible node. Next time you call this function, pass the * value returned, and the next node will be provided. * * @param blob FDT blob to use * @param node Start node for search * @param id Compatible ID to look for (enum fdt_compat_id) * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more */ int fdtdec_next_compatible(const void *blob, int node, enum fdt_compat_id id); /** * Look up an address property in a node and return it as an address. * The property must hold either one address with no trailing data or * one address with a length. This is only tested on 32-bit machines. * * @param blob FDT blob * @param node node to examine * @param prop_name name of property to find * @return address, if found, or FDT_ADDR_T_NONE if not */ fdt_addr_t fdtdec_get_addr(const void *blob, int node, const char *prop_name); /** * Look up a 32-bit integer property in a node and return it. The property * must have at least 4 bytes of data. The value of the first cell is * returned. * * @param blob FDT blob * @param node node to examine * @param prop_name name of property to find * @param default_val default value to return if the property is not found * @return integer value, if found, or default_val if not */ s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, s32 default_val); /** * Checks whether a node is enabled. * This looks for a 'status' property. If this exists, then returns 1 if * the status is 'ok' and 0 otherwise. If there is no status property, * it returns 1 on the assumption that anything mentioned should be enabled * by default. * * @param blob FDT blob * @param node node to examine * @return integer value 0 (not enabled) or 1 (enabled) */ int fdtdec_get_is_enabled(const void *blob, int node); /** * Make sure we have a valid fdt available to control U-Boot. * * If not, a message is printed to the console if the console is ready. * * @return 0 if all ok, -1 if not */ int fdtdec_prepare_fdt(void); /** * Checks that we have a valid fdt available to control U-Boot. * However, if not then for the moment nothing is done, since this function * is called too early to panic(). * * @returns 0 */ int fdtdec_check_fdt(void); /** * Find the nodes for a peripheral and return a list of them in the correct * order. This is used to enumerate all the peripherals of a certain type. * * To use this, optionally set up a /aliases node with alias properties for * a peripheral. For example, for usb you could have: * * aliases { * usb0 = "/ehci@c5008000"; * usb1 = "/ehci@c5000000"; * }; * * Pass "usb" as the name to this function and will return a list of two * nodes offsets: /ehci@c5008000 and ehci@c5000000. * * All nodes returned will match the compatible ID, as it is assumed that * all peripherals use the same driver. * * If no alias node is found, then the node list will be returned in the * order found in the fdt. If the aliases mention a node which doesn't * exist, then this will be ignored. If nodes are found with no aliases, * they will be added in any order. * * If there is a gap in the aliases, then this function return a 0 node at * that position. The return value will also count these gaps. * * This function checks node properties and will not return nodes which are * marked disabled (status = "disabled"). * * @param blob FDT blob to use * @param name Root name of alias to search for * @param id Compatible ID to look for * @param node_list Place to put list of found nodes * @param maxcount Maximum number of nodes to find * @return number of nodes found on success, FTD_ERR_... on error */ int fdtdec_find_aliases_for_id(const void *blob, const char *name, enum fdt_compat_id id, int *node_list, int maxcount); /* * This function is similar to fdtdec_find_aliases_for_id() except that it * adds to the node_list that is passed in. Any 0 elements are considered * available for allocation - others are considered already used and are * skipped. * * You can use this by calling fdtdec_find_aliases_for_id() with an * uninitialised array, then setting the elements that are returned to -1, * say, then calling this function, perhaps with a different compat id. * Any elements you get back that are >0 are new nodes added by the call * to this function. * * Note that if you have some nodes with aliases and some without, you are * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with * one compat_id may fill in positions for which you have aliases defined * for another compat_id. When you later call *this* function with the second * compat_id, the alias positions may already be used. A debug warning may * be generated in this case, but it is safest to define aliases for all * nodes when you care about the ordering. */ int fdtdec_add_aliases_for_id(const void *blob, const char *name, enum fdt_compat_id id, int *node_list, int maxcount); /* * Get the name for a compatible ID * * @param id Compatible ID to look for * @return compatible string for that id */ const char *fdtdec_get_compatible(enum fdt_compat_id id); /* Look up a phandle and follow it to its node. Then return the offset * of that node. * * @param blob FDT blob * @param node node to examine * @param prop_name name of property to find * @return node offset if found, -ve error code on error */ int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); /** * Look up a property in a node and return its contents in an integer * array of given length. The property must have at least enough data for * the array (4*count bytes). It may have more, but this will be ignored. * * @param blob FDT blob * @param node node to examine * @param prop_name name of property to find * @param array array to fill with data * @param count number of array elements * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, * or -FDT_ERR_BADLAYOUT if not enough data */ int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, u32 *array, int count); /** * Look up a boolean property in a node and return it. * * A boolean properly is true if present in the device tree and false if not * present, regardless of its value. * * @param blob FDT blob * @param node node to examine * @param prop_name name of property to find * @return 1 if the properly is present; 0 if it isn't present */ int fdtdec_get_bool(const void *blob, int node, const char *prop_name); /** * Decode a single GPIOs from an FDT. * * If the property is not found, then the GPIO structure will still be * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to * provide optional GPIOs. * * @param blob FDT blob to use * @param node Node to look at * @param prop_name Node property name * @param gpio gpio elements to fill from FDT * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. */ int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, struct fdt_gpio_state *gpio); /** * Set up a GPIO pin according to the provided gpio information. At present this * just requests the GPIO. * * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to * deal with optional GPIOs. * * @param gpio GPIO info to use for set up * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error */ int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);