129 lines
4.2 KiB
C
129 lines
4.2 KiB
C
/*
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* Copyright (c) 2011 The Chromium OS Authors.
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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/*
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* This file contains convenience functions for decoding useful and
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* enlightening information from FDTs. It is intended to be used by device
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* drivers and board-specific code within U-Boot. It aims to reduce the
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* amount of FDT munging required within U-Boot itself, so that driver code
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* changes to support FDT are minimized.
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*/
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#include <libfdt.h>
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/*
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* A typedef for a physical address. Note that fdt data is always big
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* endian even on a litle endian machine.
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*/
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#ifdef CONFIG_PHYS_64BIT
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typedef u64 fdt_addr_t;
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#define FDT_ADDR_T_NONE (-1ULL)
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#define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
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#else
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typedef u32 fdt_addr_t;
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#define FDT_ADDR_T_NONE (-1U)
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#define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
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#endif
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/* Information obtained about memory from the FDT */
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struct fdt_memory {
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fdt_addr_t start;
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fdt_addr_t end;
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};
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/**
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* Compat types that we know about and for which we might have drivers.
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* Each is named COMPAT_<dir>_<filename> where <dir> is the directory
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* within drivers.
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*/
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enum fdt_compat_id {
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COMPAT_UNKNOWN,
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COMPAT_COUNT,
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};
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/**
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* Find the next numbered alias for a peripheral. This is used to enumerate
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* all the peripherals of a certain type.
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*
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* Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
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* this function will return a pointer to the node the alias points to, and
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* then update *upto to 1. Next time you call this function, the next node
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* will be returned.
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*
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* All nodes returned will match the compatible ID, as it is assumed that
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* all peripherals use the same driver.
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*
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* @param blob FDT blob to use
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* @param name Root name of alias to search for
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* @param id Compatible ID to look for
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* @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
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*/
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int fdtdec_next_alias(const void *blob, const char *name,
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enum fdt_compat_id id, int *upto);
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/**
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* Look up an address property in a node and return it as an address.
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* The property must hold either one address with no trailing data or
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* one address with a length. This is only tested on 32-bit machines.
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*
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* @param blob FDT blob
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* @param node node to examine
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* @param prop_name name of property to find
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* @return address, if found, or FDT_ADDR_T_NONE if not
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*/
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fdt_addr_t fdtdec_get_addr(const void *blob, int node,
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const char *prop_name);
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/**
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* Look up a 32-bit integer property in a node and return it. The property
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* must have at least 4 bytes of data. The value of the first cell is
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* returned.
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*
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* @param blob FDT blob
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* @param node node to examine
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* @param prop_name name of property to find
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* @param default_val default value to return if the property is not found
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* @return integer value, if found, or default_val if not
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*/
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s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
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s32 default_val);
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/**
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* Checks whether a node is enabled.
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* This looks for a 'status' property. If this exists, then returns 1 if
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* the status is 'ok' and 0 otherwise. If there is no status property,
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* it returns the default value.
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*
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* @param blob FDT blob
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* @param node node to examine
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* @param default_val default value to return if no 'status' property exists
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* @return integer value 0/1, if found, or default_val if not
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*/
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int fdtdec_get_is_enabled(const void *blob, int node, int default_val);
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/**
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* Checks whether we have a valid fdt available to control U-Boot, and panic
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* if not.
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*/
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int fdtdec_check_fdt(void);
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