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ca900cfa29
Merge common code between PowerPC and Microblaze Signed-off-by: Grant Likely <grant.likely@secretlab.ca> Reviewed-by: Wolfram Sang <w.sang@pengutronix.de> Tested-by: Michal Simek <monstr@monstr.eu>
145 lines
3.1 KiB
C
145 lines
3.1 KiB
C
/*
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* Functions for working with the Flattened Device Tree data format
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*
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* Copyright 2009 Benjamin Herrenschmidt, IBM Corp
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* benh@kernel.crashing.org
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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
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* version 2 as published by the Free Software Foundation.
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*/
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#include <linux/of.h>
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#include <linux/of_fdt.h>
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struct boot_param_header *initial_boot_params;
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char *find_flat_dt_string(u32 offset)
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{
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return ((char *)initial_boot_params) +
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initial_boot_params->off_dt_strings + offset;
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}
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/**
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* of_scan_flat_dt - scan flattened tree blob and call callback on each.
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* @it: callback function
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* @data: context data pointer
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*
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* This function is used to scan the flattened device-tree, it is
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* used to extract the memory information at boot before we can
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* unflatten the tree
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*/
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int __init of_scan_flat_dt(int (*it)(unsigned long node,
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const char *uname, int depth,
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void *data),
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void *data)
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{
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unsigned long p = ((unsigned long)initial_boot_params) +
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initial_boot_params->off_dt_struct;
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int rc = 0;
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int depth = -1;
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do {
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u32 tag = *((u32 *)p);
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char *pathp;
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p += 4;
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if (tag == OF_DT_END_NODE) {
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depth--;
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continue;
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}
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if (tag == OF_DT_NOP)
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continue;
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if (tag == OF_DT_END)
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break;
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if (tag == OF_DT_PROP) {
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u32 sz = *((u32 *)p);
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p += 8;
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if (initial_boot_params->version < 0x10)
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p = _ALIGN(p, sz >= 8 ? 8 : 4);
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p += sz;
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p = _ALIGN(p, 4);
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continue;
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}
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if (tag != OF_DT_BEGIN_NODE) {
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pr_err("Invalid tag %x in flat device tree!\n", tag);
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return -EINVAL;
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}
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depth++;
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pathp = (char *)p;
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p = _ALIGN(p + strlen(pathp) + 1, 4);
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if ((*pathp) == '/') {
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char *lp, *np;
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for (lp = NULL, np = pathp; *np; np++)
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if ((*np) == '/')
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lp = np+1;
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if (lp != NULL)
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pathp = lp;
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}
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rc = it(p, pathp, depth, data);
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if (rc != 0)
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break;
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} while (1);
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return rc;
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}
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/**
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* of_get_flat_dt_root - find the root node in the flat blob
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*/
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unsigned long __init of_get_flat_dt_root(void)
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{
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unsigned long p = ((unsigned long)initial_boot_params) +
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initial_boot_params->off_dt_struct;
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while (*((u32 *)p) == OF_DT_NOP)
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p += 4;
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BUG_ON(*((u32 *)p) != OF_DT_BEGIN_NODE);
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p += 4;
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return _ALIGN(p + strlen((char *)p) + 1, 4);
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}
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/**
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* of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
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*
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* This function can be used within scan_flattened_dt callback to get
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* access to properties
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*/
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void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
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unsigned long *size)
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{
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unsigned long p = node;
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do {
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u32 tag = *((u32 *)p);
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u32 sz, noff;
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const char *nstr;
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p += 4;
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if (tag == OF_DT_NOP)
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continue;
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if (tag != OF_DT_PROP)
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return NULL;
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sz = *((u32 *)p);
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noff = *((u32 *)(p + 4));
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p += 8;
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if (initial_boot_params->version < 0x10)
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p = _ALIGN(p, sz >= 8 ? 8 : 4);
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nstr = find_flat_dt_string(noff);
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if (nstr == NULL) {
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pr_warning("Can't find property index name !\n");
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return NULL;
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}
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if (strcmp(name, nstr) == 0) {
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if (size)
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*size = sz;
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return (void *)p;
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}
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p += sz;
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p = _ALIGN(p, 4);
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} while (1);
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}
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