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Diffstat (limited to 'include/fdtdec.h')
-rw-r--r-- | include/fdtdec.h | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/include/fdtdec.h b/include/fdtdec.h new file mode 100644 index 0000000..d871cdd --- /dev/null +++ b/include/fdtdec.h @@ -0,0 +1,128 @@ +/* + * 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_COUNT, +}; + +/** + * 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); + +/** + * 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 the default value. + * + * @param blob FDT blob + * @param node node to examine + * @param default_val default value to return if no 'status' property exists + * @return integer value 0/1, if found, or default_val if not + */ +int fdtdec_get_is_enabled(const void *blob, int node, int default_val); + +/** + * Checks whether we have a valid fdt available to control U-Boot, and panic + * if not. + */ +int fdtdec_check_fdt(void); |