2 * Functions for working with the Flattened Device Tree data format
4 * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
5 * benh@kernel.crashing.org
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation.
12 #include <linux/kernel.h>
13 #include <linux/initrd.h>
15 #include <linux/of_fdt.h>
16 #include <linux/string.h>
17 #include <linux/errno.h>
20 #include <asm/machdep.h>
21 #endif /* CONFIG_PPC */
25 char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
27 return ((char *)blob) +
28 be32_to_cpu(blob->off_dt_strings) + offset;
32 * of_fdt_get_property - Given a node in the given flat blob, return
35 void *of_fdt_get_property(struct boot_param_header *blob,
36 unsigned long node, const char *name,
39 unsigned long p = node;
42 u32 tag = be32_to_cpup((__be32 *)p);
49 if (tag != OF_DT_PROP)
52 sz = be32_to_cpup((__be32 *)p);
53 noff = be32_to_cpup((__be32 *)(p + 4));
55 if (be32_to_cpu(blob->version) < 0x10)
56 p = ALIGN(p, sz >= 8 ? 8 : 4);
58 nstr = of_fdt_get_string(blob, noff);
60 pr_warning("Can't find property index name !\n");
63 if (strcmp(name, nstr) == 0) {
74 * of_fdt_is_compatible - Return true if given node from the given blob has
75 * compat in its compatible list
76 * @blob: A device tree blob
78 * @compat: compatible string to compare with compatible list.
80 int of_fdt_is_compatible(struct boot_param_header *blob,
81 unsigned long node, const char *compat)
84 unsigned long cplen, l;
86 cp = of_fdt_get_property(blob, node, "compatible", &cplen);
90 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
100 static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size,
105 *mem = ALIGN(*mem, align);
113 * unflatten_dt_node - Alloc and populate a device_node from the flat tree
114 * @blob: The parent device tree blob
115 * @p: pointer to node in flat tree
116 * @dad: Parent struct device_node
117 * @allnextpp: pointer to ->allnext from last allocated device_node
118 * @fpsize: Size of the node path up at the current depth.
120 unsigned long unflatten_dt_node(struct boot_param_header *blob,
123 struct device_node *dad,
124 struct device_node ***allnextpp,
125 unsigned long fpsize)
127 struct device_node *np;
128 struct property *pp, **prev_pp = NULL;
131 unsigned int l, allocl;
135 tag = be32_to_cpup((__be32 *)(*p));
136 if (tag != OF_DT_BEGIN_NODE) {
137 pr_err("Weird tag at start of node: %x\n", tag);
142 l = allocl = strlen(pathp) + 1;
143 *p = ALIGN(*p + l, 4);
145 /* version 0x10 has a more compact unit name here instead of the full
146 * path. we accumulate the full path size using "fpsize", we'll rebuild
147 * it later. We detect this because the first character of the name is
150 if ((*pathp) != '/') {
153 /* root node: special case. fpsize accounts for path
154 * plus terminating zero. root node only has '/', so
155 * fpsize should be 2, but we want to avoid the first
156 * level nodes to have two '/' so we use fpsize 1 here
161 /* account for '/' and path size minus terminal 0
169 np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
170 __alignof__(struct device_node));
172 memset(np, 0, sizeof(*np));
173 np->full_name = ((char *)np) + sizeof(struct device_node);
175 char *fn = np->full_name;
176 /* rebuild full path for new format */
177 if (dad && dad->parent) {
178 strcpy(fn, dad->full_name);
180 if ((strlen(fn) + l + 1) != allocl) {
181 pr_debug("%s: p: %d, l: %d, a: %d\n",
182 pathp, (int)strlen(fn),
189 memcpy(fn, pathp, l);
191 memcpy(np->full_name, pathp, l);
192 prev_pp = &np->properties;
194 *allnextpp = &np->allnext;
197 /* we temporarily use the next field as `last_child'*/
198 if (dad->next == NULL)
201 dad->next->sibling = np;
204 kref_init(&np->kref);
210 tag = be32_to_cpup((__be32 *)(*p));
211 if (tag == OF_DT_NOP) {
215 if (tag != OF_DT_PROP)
218 sz = be32_to_cpup((__be32 *)(*p));
219 noff = be32_to_cpup((__be32 *)((*p) + 4));
221 if (be32_to_cpu(blob->version) < 0x10)
222 *p = ALIGN(*p, sz >= 8 ? 8 : 4);
224 pname = of_fdt_get_string(blob, noff);
226 pr_info("Can't find property name in list !\n");
229 if (strcmp(pname, "name") == 0)
231 l = strlen(pname) + 1;
232 pp = unflatten_dt_alloc(&mem, sizeof(struct property),
233 __alignof__(struct property));
235 /* We accept flattened tree phandles either in
236 * ePAPR-style "phandle" properties, or the
237 * legacy "linux,phandle" properties. If both
238 * appear and have different values, things
239 * will get weird. Don't do that. */
240 if ((strcmp(pname, "phandle") == 0) ||
241 (strcmp(pname, "linux,phandle") == 0)) {
242 if (np->phandle == 0)
243 np->phandle = be32_to_cpup((__be32*)*p);
245 /* And we process the "ibm,phandle" property
246 * used in pSeries dynamic device tree
248 if (strcmp(pname, "ibm,phandle") == 0)
249 np->phandle = be32_to_cpup((__be32 *)*p);
252 pp->value = (void *)*p;
256 *p = ALIGN((*p) + sz, 4);
258 /* with version 0x10 we may not have the name property, recreate
259 * it here from the unit name if absent
262 char *p1 = pathp, *ps = pathp, *pa = NULL;
275 pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz,
276 __alignof__(struct property));
283 memcpy(pp->value, ps, sz - 1);
284 ((char *)pp->value)[sz - 1] = 0;
285 pr_debug("fixed up name for %s -> %s\n", pathp,
291 np->name = of_get_property(np, "name", NULL);
292 np->type = of_get_property(np, "device_type", NULL);
299 while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
300 if (tag == OF_DT_NOP)
303 mem = unflatten_dt_node(blob, mem, p, np, allnextpp,
305 tag = be32_to_cpup((__be32 *)(*p));
307 if (tag != OF_DT_END_NODE) {
308 pr_err("Weird tag at end of node: %x\n", tag);
315 /* Everything below here references initial_boot_params directly. */
316 int __initdata dt_root_addr_cells;
317 int __initdata dt_root_size_cells;
319 struct boot_param_header *initial_boot_params;
321 #ifdef CONFIG_OF_EARLY_FLATTREE
324 * of_scan_flat_dt - scan flattened tree blob and call callback on each.
325 * @it: callback function
326 * @data: context data pointer
328 * This function is used to scan the flattened device-tree, it is
329 * used to extract the memory information at boot before we can
332 int __init of_scan_flat_dt(int (*it)(unsigned long node,
333 const char *uname, int depth,
337 unsigned long p = ((unsigned long)initial_boot_params) +
338 be32_to_cpu(initial_boot_params->off_dt_struct);
343 u32 tag = be32_to_cpup((__be32 *)p);
347 if (tag == OF_DT_END_NODE) {
351 if (tag == OF_DT_NOP)
353 if (tag == OF_DT_END)
355 if (tag == OF_DT_PROP) {
356 u32 sz = be32_to_cpup((__be32 *)p);
358 if (be32_to_cpu(initial_boot_params->version) < 0x10)
359 p = ALIGN(p, sz >= 8 ? 8 : 4);
364 if (tag != OF_DT_BEGIN_NODE) {
365 pr_err("Invalid tag %x in flat device tree!\n", tag);
370 p = ALIGN(p + strlen(pathp) + 1, 4);
371 if ((*pathp) == '/') {
373 for (lp = NULL, np = pathp; *np; np++)
379 rc = it(p, pathp, depth, data);
388 * of_get_flat_dt_root - find the root node in the flat blob
390 unsigned long __init of_get_flat_dt_root(void)
392 unsigned long p = ((unsigned long)initial_boot_params) +
393 be32_to_cpu(initial_boot_params->off_dt_struct);
395 while (be32_to_cpup((__be32 *)p) == OF_DT_NOP)
397 BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE);
399 return ALIGN(p + strlen((char *)p) + 1, 4);
403 * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
405 * This function can be used within scan_flattened_dt callback to get
406 * access to properties
408 void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
411 return of_fdt_get_property(initial_boot_params, node, name, size);
415 * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
416 * @node: node to test
417 * @compat: compatible string to compare with compatible list.
419 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
421 return of_fdt_is_compatible(initial_boot_params, node, compat);
424 #ifdef CONFIG_BLK_DEV_INITRD
426 * early_init_dt_check_for_initrd - Decode initrd location from flat tree
427 * @node: reference to node containing initrd location ('chosen')
429 void __init early_init_dt_check_for_initrd(unsigned long node)
431 unsigned long start, end, len;
434 pr_debug("Looking for initrd properties... ");
436 prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
439 start = of_read_ulong(prop, len/4);
441 prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
444 end = of_read_ulong(prop, len/4);
446 early_init_dt_setup_initrd_arch(start, end);
447 pr_debug("initrd_start=0x%lx initrd_end=0x%lx\n", start, end);
450 inline void early_init_dt_check_for_initrd(unsigned long node)
453 #endif /* CONFIG_BLK_DEV_INITRD */
456 * early_init_dt_scan_root - fetch the top level address and size cells
458 int __init early_init_dt_scan_root(unsigned long node, const char *uname,
459 int depth, void *data)
466 dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
467 dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
469 prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
471 dt_root_size_cells = be32_to_cpup(prop);
472 pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
474 prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
476 dt_root_addr_cells = be32_to_cpup(prop);
477 pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
483 u64 __init dt_mem_next_cell(int s, __be32 **cellp)
488 return of_read_number(p, s);
492 * early_init_dt_scan_memory - Look for an parse memory nodes
494 int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
495 int depth, void *data)
497 char *type = of_get_flat_dt_prop(node, "device_type", NULL);
501 /* We are scanning "memory" nodes only */
504 * The longtrail doesn't have a device_type on the
505 * /memory node, so look for the node called /memory@0.
507 if (depth != 1 || strcmp(uname, "memory@0") != 0)
509 } else if (strcmp(type, "memory") != 0)
512 reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
514 reg = of_get_flat_dt_prop(node, "reg", &l);
518 endp = reg + (l / sizeof(__be32));
520 pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
521 uname, l, reg[0], reg[1], reg[2], reg[3]);
523 while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
526 base = dt_mem_next_cell(dt_root_addr_cells, ®);
527 size = dt_mem_next_cell(dt_root_size_cells, ®);
531 pr_debug(" - %llx , %llx\n", (unsigned long long)base,
532 (unsigned long long)size);
534 early_init_dt_add_memory_arch(base, size);
540 int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
541 int depth, void *data)
546 pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
549 (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
552 early_init_dt_check_for_initrd(node);
554 /* Retreive command line */
555 p = of_get_flat_dt_prop(node, "bootargs", &l);
556 if (p != NULL && l > 0)
557 strlcpy(cmd_line, p, min((int)l, COMMAND_LINE_SIZE));
559 #ifdef CONFIG_CMDLINE
560 #ifndef CONFIG_CMDLINE_FORCE
561 if (p == NULL || l == 0 || (l == 1 && (*p) == 0))
563 strlcpy(cmd_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
564 #endif /* CONFIG_CMDLINE */
566 pr_debug("Command line is: %s\n", cmd_line);
573 * unflatten_device_tree - create tree of device_nodes from flat blob
575 * unflattens the device-tree passed by the firmware, creating the
576 * tree of struct device_node. It also fills the "name" and "type"
577 * pointers of the nodes so the normal device-tree walking functions
580 void __init unflatten_device_tree(void)
582 unsigned long start, mem, size;
583 struct device_node **allnextp = &allnodes;
585 pr_debug(" -> unflatten_device_tree()\n");
587 if (!initial_boot_params) {
588 pr_debug("No device tree pointer\n");
592 pr_debug("Unflattening device tree:\n");
593 pr_debug("magic: %08x\n", be32_to_cpu(initial_boot_params->magic));
594 pr_debug("size: %08x\n", be32_to_cpu(initial_boot_params->totalsize));
595 pr_debug("version: %08x\n", be32_to_cpu(initial_boot_params->version));
597 if (be32_to_cpu(initial_boot_params->magic) != OF_DT_HEADER) {
598 pr_err("Invalid device tree blob header\n");
602 /* First pass, scan for size */
603 start = ((unsigned long)initial_boot_params) +
604 be32_to_cpu(initial_boot_params->off_dt_struct);
605 size = unflatten_dt_node(initial_boot_params, 0, &start,
607 size = (size | 3) + 1;
609 pr_debug(" size is %lx, allocating...\n", size);
611 /* Allocate memory for the expanded device tree */
612 mem = early_init_dt_alloc_memory_arch(size + 4,
613 __alignof__(struct device_node));
614 mem = (unsigned long) __va(mem);
616 ((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);
618 pr_debug(" unflattening %lx...\n", mem);
620 /* Second pass, do actual unflattening */
621 start = ((unsigned long)initial_boot_params) +
622 be32_to_cpu(initial_boot_params->off_dt_struct);
623 unflatten_dt_node(initial_boot_params, mem, &start,
625 if (be32_to_cpup((__be32 *)start) != OF_DT_END)
626 pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start));
627 if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
628 pr_warning("End of tree marker overwritten: %08x\n",
629 be32_to_cpu(((__be32 *)mem)[size / 4]));
632 /* Get pointer to OF "/chosen" node for use everywhere */
633 of_chosen = of_find_node_by_path("/chosen");
634 if (of_chosen == NULL)
635 of_chosen = of_find_node_by_path("/chosen@0");
637 pr_debug(" <- unflatten_device_tree()\n");
640 #endif /* CONFIG_OF_EARLY_FLATTREE */