| /* |
| * Functions for working with the Flattened Device Tree data format |
| * |
| * Copyright 2009 Benjamin Herrenschmidt, IBM Corp |
| * benh@kernel.crashing.org |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * version 2 as published by the Free Software Foundation. |
| */ |
| |
| #include <linux/of.h> |
| #include <linux/of_fdt.h> |
| |
| struct boot_param_header *initial_boot_params; |
| |
| char *find_flat_dt_string(u32 offset) |
| { |
| return ((char *)initial_boot_params) + |
| initial_boot_params->off_dt_strings + offset; |
| } |
| |
| /** |
| * of_scan_flat_dt - scan flattened tree blob and call callback on each. |
| * @it: callback function |
| * @data: context data pointer |
| * |
| * This function is used to scan the flattened device-tree, it is |
| * used to extract the memory information at boot before we can |
| * unflatten the tree |
| */ |
| int __init of_scan_flat_dt(int (*it)(unsigned long node, |
| const char *uname, int depth, |
| void *data), |
| void *data) |
| { |
| unsigned long p = ((unsigned long)initial_boot_params) + |
| initial_boot_params->off_dt_struct; |
| int rc = 0; |
| int depth = -1; |
| |
| do { |
| u32 tag = *((u32 *)p); |
| char *pathp; |
| |
| p += 4; |
| if (tag == OF_DT_END_NODE) { |
| depth--; |
| continue; |
| } |
| if (tag == OF_DT_NOP) |
| continue; |
| if (tag == OF_DT_END) |
| break; |
| if (tag == OF_DT_PROP) { |
| u32 sz = *((u32 *)p); |
| p += 8; |
| if (initial_boot_params->version < 0x10) |
| p = _ALIGN(p, sz >= 8 ? 8 : 4); |
| p += sz; |
| p = _ALIGN(p, 4); |
| continue; |
| } |
| if (tag != OF_DT_BEGIN_NODE) { |
| pr_err("Invalid tag %x in flat device tree!\n", tag); |
| return -EINVAL; |
| } |
| depth++; |
| pathp = (char *)p; |
| p = _ALIGN(p + strlen(pathp) + 1, 4); |
| if ((*pathp) == '/') { |
| char *lp, *np; |
| for (lp = NULL, np = pathp; *np; np++) |
| if ((*np) == '/') |
| lp = np+1; |
| if (lp != NULL) |
| pathp = lp; |
| } |
| rc = it(p, pathp, depth, data); |
| if (rc != 0) |
| break; |
| } while (1); |
| |
| return rc; |
| } |
| |
| /** |
| * of_get_flat_dt_root - find the root node in the flat blob |
| */ |
| unsigned long __init of_get_flat_dt_root(void) |
| { |
| unsigned long p = ((unsigned long)initial_boot_params) + |
| initial_boot_params->off_dt_struct; |
| |
| while (*((u32 *)p) == OF_DT_NOP) |
| p += 4; |
| BUG_ON(*((u32 *)p) != OF_DT_BEGIN_NODE); |
| p += 4; |
| return _ALIGN(p + strlen((char *)p) + 1, 4); |
| } |
| |
| /** |
| * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr |
| * |
| * This function can be used within scan_flattened_dt callback to get |
| * access to properties |
| */ |
| void *__init of_get_flat_dt_prop(unsigned long node, const char *name, |
| unsigned long *size) |
| { |
| unsigned long p = node; |
| |
| do { |
| u32 tag = *((u32 *)p); |
| u32 sz, noff; |
| const char *nstr; |
| |
| p += 4; |
| if (tag == OF_DT_NOP) |
| continue; |
| if (tag != OF_DT_PROP) |
| return NULL; |
| |
| sz = *((u32 *)p); |
| noff = *((u32 *)(p + 4)); |
| p += 8; |
| if (initial_boot_params->version < 0x10) |
| p = _ALIGN(p, sz >= 8 ? 8 : 4); |
| |
| nstr = find_flat_dt_string(noff); |
| if (nstr == NULL) { |
| pr_warning("Can't find property index name !\n"); |
| return NULL; |
| } |
| if (strcmp(name, nstr) == 0) { |
| if (size) |
| *size = sz; |
| return (void *)p; |
| } |
| p += sz; |
| p = _ALIGN(p, 4); |
| } while (1); |
| } |
| |
| /** |
| * of_flat_dt_is_compatible - Return true if given node has compat in compatible list |
| * @node: node to test |
| * @compat: compatible string to compare with compatible list. |
| */ |
| int __init of_flat_dt_is_compatible(unsigned long node, const char *compat) |
| { |
| const char *cp; |
| unsigned long cplen, l; |
| |
| cp = of_get_flat_dt_prop(node, "compatible", &cplen); |
| if (cp == NULL) |
| return 0; |
| while (cplen > 0) { |
| if (strncasecmp(cp, compat, strlen(compat)) == 0) |
| return 1; |
| l = strlen(cp) + 1; |
| cp += l; |
| cplen -= l; |
| } |
| |
| return 0; |
| } |
| |