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>
14 #include <linux/module.h>
16 #include <linux/of_fdt.h>
17 #include <linux/string.h>
18 #include <linux/errno.h>
19 #include <linux/slab.h>
21 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */
23 #include <asm/machdep.h>
24 #endif /* CONFIG_PPC */
26 #include <asm/setup.h>
29 char *of_fdt_get_string(struct boot_param_header
*blob
, u32 offset
)
31 return ((char *)blob
) +
32 be32_to_cpu(blob
->off_dt_strings
) + offset
;
36 * of_fdt_get_property - Given a node in the given flat blob, return
39 void *of_fdt_get_property(struct boot_param_header
*blob
,
40 unsigned long node
, const char *name
,
43 unsigned long p
= node
;
46 u32 tag
= be32_to_cpup((__be32
*)p
);
53 if (tag
!= OF_DT_PROP
)
56 sz
= be32_to_cpup((__be32
*)p
);
57 noff
= be32_to_cpup((__be32
*)(p
+ 4));
59 if (be32_to_cpu(blob
->version
) < 0x10)
60 p
= ALIGN(p
, sz
>= 8 ? 8 : 4);
62 nstr
= of_fdt_get_string(blob
, noff
);
64 pr_warning("Can't find property index name !\n");
67 if (strcmp(name
, nstr
) == 0) {
78 * of_fdt_is_compatible - Return true if given node from the given blob has
79 * compat in its compatible list
80 * @blob: A device tree blob
82 * @compat: compatible string to compare with compatible list.
84 * On match, returns a non-zero value with smaller values returned for more
85 * specific compatible values.
87 int of_fdt_is_compatible(struct boot_param_header
*blob
,
88 unsigned long node
, const char *compat
)
91 unsigned long cplen
, l
, score
= 0;
93 cp
= of_fdt_get_property(blob
, node
, "compatible", &cplen
);
98 if (of_compat_cmp(cp
, compat
, strlen(compat
)) == 0)
109 * of_fdt_match - Return true if node matches a list of compatible values
111 int of_fdt_match(struct boot_param_header
*blob
, unsigned long node
,
112 const char *const *compat
)
114 unsigned int tmp
, score
= 0;
120 tmp
= of_fdt_is_compatible(blob
, node
, *compat
);
121 if (tmp
&& (score
== 0 || (tmp
< score
)))
129 static void *unflatten_dt_alloc(unsigned long *mem
, unsigned long size
,
134 *mem
= ALIGN(*mem
, align
);
142 * unflatten_dt_node - Alloc and populate a device_node from the flat tree
143 * @blob: The parent device tree blob
144 * @mem: Memory chunk to use for allocating device nodes and properties
145 * @p: pointer to node in flat tree
146 * @dad: Parent struct device_node
147 * @allnextpp: pointer to ->allnext from last allocated device_node
148 * @fpsize: Size of the node path up at the current depth.
150 static unsigned long unflatten_dt_node(struct boot_param_header
*blob
,
153 struct device_node
*dad
,
154 struct device_node
***allnextpp
,
155 unsigned long fpsize
)
157 struct device_node
*np
;
158 struct property
*pp
, **prev_pp
= NULL
;
161 unsigned int l
, allocl
;
165 tag
= be32_to_cpup((__be32
*)(*p
));
166 if (tag
!= OF_DT_BEGIN_NODE
) {
167 pr_err("Weird tag at start of node: %x\n", tag
);
172 l
= allocl
= strlen(pathp
) + 1;
173 *p
= ALIGN(*p
+ l
, 4);
175 /* version 0x10 has a more compact unit name here instead of the full
176 * path. we accumulate the full path size using "fpsize", we'll rebuild
177 * it later. We detect this because the first character of the name is
180 if ((*pathp
) != '/') {
183 /* root node: special case. fpsize accounts for path
184 * plus terminating zero. root node only has '/', so
185 * fpsize should be 2, but we want to avoid the first
186 * level nodes to have two '/' so we use fpsize 1 here
191 /* account for '/' and path size minus terminal 0
199 np
= unflatten_dt_alloc(&mem
, sizeof(struct device_node
) + allocl
,
200 __alignof__(struct device_node
));
202 memset(np
, 0, sizeof(*np
));
203 np
->full_name
= ((char *)np
) + sizeof(struct device_node
);
205 char *fn
= np
->full_name
;
206 /* rebuild full path for new format */
207 if (dad
&& dad
->parent
) {
208 strcpy(fn
, dad
->full_name
);
210 if ((strlen(fn
) + l
+ 1) != allocl
) {
211 pr_debug("%s: p: %d, l: %d, a: %d\n",
212 pathp
, (int)strlen(fn
),
219 memcpy(fn
, pathp
, l
);
221 memcpy(np
->full_name
, pathp
, l
);
222 prev_pp
= &np
->properties
;
224 *allnextpp
= &np
->allnext
;
227 /* we temporarily use the next field as `last_child'*/
228 if (dad
->next
== NULL
)
231 dad
->next
->sibling
= np
;
234 kref_init(&np
->kref
);
236 /* process properties */
241 tag
= be32_to_cpup((__be32
*)(*p
));
242 if (tag
== OF_DT_NOP
) {
246 if (tag
!= OF_DT_PROP
)
249 sz
= be32_to_cpup((__be32
*)(*p
));
250 noff
= be32_to_cpup((__be32
*)((*p
) + 4));
252 if (be32_to_cpu(blob
->version
) < 0x10)
253 *p
= ALIGN(*p
, sz
>= 8 ? 8 : 4);
255 pname
= of_fdt_get_string(blob
, noff
);
257 pr_info("Can't find property name in list !\n");
260 if (strcmp(pname
, "name") == 0)
262 l
= strlen(pname
) + 1;
263 pp
= unflatten_dt_alloc(&mem
, sizeof(struct property
),
264 __alignof__(struct property
));
266 /* We accept flattened tree phandles either in
267 * ePAPR-style "phandle" properties, or the
268 * legacy "linux,phandle" properties. If both
269 * appear and have different values, things
270 * will get weird. Don't do that. */
271 if ((strcmp(pname
, "phandle") == 0) ||
272 (strcmp(pname
, "linux,phandle") == 0)) {
273 if (np
->phandle
== 0)
274 np
->phandle
= be32_to_cpup((__be32
*)*p
);
276 /* And we process the "ibm,phandle" property
277 * used in pSeries dynamic device tree
279 if (strcmp(pname
, "ibm,phandle") == 0)
280 np
->phandle
= be32_to_cpup((__be32
*)*p
);
283 pp
->value
= (void *)*p
;
287 *p
= ALIGN((*p
) + sz
, 4);
289 /* with version 0x10 we may not have the name property, recreate
290 * it here from the unit name if absent
293 char *p1
= pathp
, *ps
= pathp
, *pa
= NULL
;
306 pp
= unflatten_dt_alloc(&mem
, sizeof(struct property
) + sz
,
307 __alignof__(struct property
));
314 memcpy(pp
->value
, ps
, sz
- 1);
315 ((char *)pp
->value
)[sz
- 1] = 0;
316 pr_debug("fixed up name for %s -> %s\n", pathp
,
322 np
->name
= of_get_property(np
, "name", NULL
);
323 np
->type
= of_get_property(np
, "device_type", NULL
);
330 while (tag
== OF_DT_BEGIN_NODE
|| tag
== OF_DT_NOP
) {
331 if (tag
== OF_DT_NOP
)
334 mem
= unflatten_dt_node(blob
, mem
, p
, np
, allnextpp
,
336 tag
= be32_to_cpup((__be32
*)(*p
));
338 if (tag
!= OF_DT_END_NODE
) {
339 pr_err("Weird tag at end of node: %x\n", tag
);
347 * __unflatten_device_tree - create tree of device_nodes from flat blob
349 * unflattens a device-tree, creating the
350 * tree of struct device_node. It also fills the "name" and "type"
351 * pointers of the nodes so the normal device-tree walking functions
353 * @blob: The blob to expand
354 * @mynodes: The device_node tree created by the call
355 * @dt_alloc: An allocator that provides a virtual address to memory
356 * for the resulting tree
358 static void __unflatten_device_tree(struct boot_param_header
*blob
,
359 struct device_node
**mynodes
,
360 void * (*dt_alloc
)(u64 size
, u64 align
))
362 unsigned long start
, mem
, size
;
363 struct device_node
**allnextp
= mynodes
;
365 pr_debug(" -> unflatten_device_tree()\n");
368 pr_debug("No device tree pointer\n");
372 pr_debug("Unflattening device tree:\n");
373 pr_debug("magic: %08x\n", be32_to_cpu(blob
->magic
));
374 pr_debug("size: %08x\n", be32_to_cpu(blob
->totalsize
));
375 pr_debug("version: %08x\n", be32_to_cpu(blob
->version
));
377 if (be32_to_cpu(blob
->magic
) != OF_DT_HEADER
) {
378 pr_err("Invalid device tree blob header\n");
382 /* First pass, scan for size */
383 start
= ((unsigned long)blob
) +
384 be32_to_cpu(blob
->off_dt_struct
);
385 size
= unflatten_dt_node(blob
, 0, &start
, NULL
, NULL
, 0);
386 size
= (size
| 3) + 1;
388 pr_debug(" size is %lx, allocating...\n", size
);
390 /* Allocate memory for the expanded device tree */
391 mem
= (unsigned long)
392 dt_alloc(size
+ 4, __alignof__(struct device_node
));
394 ((__be32
*)mem
)[size
/ 4] = cpu_to_be32(0xdeadbeef);
396 pr_debug(" unflattening %lx...\n", mem
);
398 /* Second pass, do actual unflattening */
399 start
= ((unsigned long)blob
) +
400 be32_to_cpu(blob
->off_dt_struct
);
401 unflatten_dt_node(blob
, mem
, &start
, NULL
, &allnextp
, 0);
402 if (be32_to_cpup((__be32
*)start
) != OF_DT_END
)
403 pr_warning("Weird tag at end of tree: %08x\n", *((u32
*)start
));
404 if (be32_to_cpu(((__be32
*)mem
)[size
/ 4]) != 0xdeadbeef)
405 pr_warning("End of tree marker overwritten: %08x\n",
406 be32_to_cpu(((__be32
*)mem
)[size
/ 4]));
409 pr_debug(" <- unflatten_device_tree()\n");
412 static void *kernel_tree_alloc(u64 size
, u64 align
)
414 return kzalloc(size
, GFP_KERNEL
);
418 * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
420 * unflattens the device-tree passed by the firmware, creating the
421 * tree of struct device_node. It also fills the "name" and "type"
422 * pointers of the nodes so the normal device-tree walking functions
425 void of_fdt_unflatten_tree(unsigned long *blob
,
426 struct device_node
**mynodes
)
428 struct boot_param_header
*device_tree
=
429 (struct boot_param_header
*)blob
;
430 __unflatten_device_tree(device_tree
, mynodes
, &kernel_tree_alloc
);
432 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree
);
434 /* Everything below here references initial_boot_params directly. */
435 int __initdata dt_root_addr_cells
;
436 int __initdata dt_root_size_cells
;
438 struct boot_param_header
*initial_boot_params
;
440 #ifdef CONFIG_OF_EARLY_FLATTREE
443 * of_scan_flat_dt - scan flattened tree blob and call callback on each.
444 * @it: callback function
445 * @data: context data pointer
447 * This function is used to scan the flattened device-tree, it is
448 * used to extract the memory information at boot before we can
451 int __init
of_scan_flat_dt(int (*it
)(unsigned long node
,
452 const char *uname
, int depth
,
456 unsigned long p
= ((unsigned long)initial_boot_params
) +
457 be32_to_cpu(initial_boot_params
->off_dt_struct
);
462 u32 tag
= be32_to_cpup((__be32
*)p
);
466 if (tag
== OF_DT_END_NODE
) {
470 if (tag
== OF_DT_NOP
)
472 if (tag
== OF_DT_END
)
474 if (tag
== OF_DT_PROP
) {
475 u32 sz
= be32_to_cpup((__be32
*)p
);
477 if (be32_to_cpu(initial_boot_params
->version
) < 0x10)
478 p
= ALIGN(p
, sz
>= 8 ? 8 : 4);
483 if (tag
!= OF_DT_BEGIN_NODE
) {
484 pr_err("Invalid tag %x in flat device tree!\n", tag
);
489 p
= ALIGN(p
+ strlen(pathp
) + 1, 4);
490 if ((*pathp
) == '/') {
492 for (lp
= NULL
, np
= pathp
; *np
; np
++)
498 rc
= it(p
, pathp
, depth
, data
);
507 * of_get_flat_dt_root - find the root node in the flat blob
509 unsigned long __init
of_get_flat_dt_root(void)
511 unsigned long p
= ((unsigned long)initial_boot_params
) +
512 be32_to_cpu(initial_boot_params
->off_dt_struct
);
514 while (be32_to_cpup((__be32
*)p
) == OF_DT_NOP
)
516 BUG_ON(be32_to_cpup((__be32
*)p
) != OF_DT_BEGIN_NODE
);
518 return ALIGN(p
+ strlen((char *)p
) + 1, 4);
522 * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
524 * This function can be used within scan_flattened_dt callback to get
525 * access to properties
527 void *__init
of_get_flat_dt_prop(unsigned long node
, const char *name
,
530 return of_fdt_get_property(initial_boot_params
, node
, name
, size
);
534 * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
535 * @node: node to test
536 * @compat: compatible string to compare with compatible list.
538 int __init
of_flat_dt_is_compatible(unsigned long node
, const char *compat
)
540 return of_fdt_is_compatible(initial_boot_params
, node
, compat
);
544 * of_flat_dt_match - Return true if node matches a list of compatible values
546 int __init
of_flat_dt_match(unsigned long node
, const char *const *compat
)
548 return of_fdt_match(initial_boot_params
, node
, compat
);
551 #ifdef CONFIG_BLK_DEV_INITRD
553 * early_init_dt_check_for_initrd - Decode initrd location from flat tree
554 * @node: reference to node containing initrd location ('chosen')
556 void __init
early_init_dt_check_for_initrd(unsigned long node
)
558 unsigned long start
, end
, len
;
561 pr_debug("Looking for initrd properties... ");
563 prop
= of_get_flat_dt_prop(node
, "linux,initrd-start", &len
);
566 start
= of_read_ulong(prop
, len
/4);
568 prop
= of_get_flat_dt_prop(node
, "linux,initrd-end", &len
);
571 end
= of_read_ulong(prop
, len
/4);
573 early_init_dt_setup_initrd_arch(start
, end
);
574 pr_debug("initrd_start=0x%lx initrd_end=0x%lx\n", start
, end
);
577 inline void early_init_dt_check_for_initrd(unsigned long node
)
580 #endif /* CONFIG_BLK_DEV_INITRD */
583 * early_init_dt_scan_root - fetch the top level address and size cells
585 int __init
early_init_dt_scan_root(unsigned long node
, const char *uname
,
586 int depth
, void *data
)
593 dt_root_size_cells
= OF_ROOT_NODE_SIZE_CELLS_DEFAULT
;
594 dt_root_addr_cells
= OF_ROOT_NODE_ADDR_CELLS_DEFAULT
;
596 prop
= of_get_flat_dt_prop(node
, "#size-cells", NULL
);
598 dt_root_size_cells
= be32_to_cpup(prop
);
599 pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells
);
601 prop
= of_get_flat_dt_prop(node
, "#address-cells", NULL
);
603 dt_root_addr_cells
= be32_to_cpup(prop
);
604 pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells
);
610 u64 __init
dt_mem_next_cell(int s
, __be32
**cellp
)
615 return of_read_number(p
, s
);
619 * early_init_dt_scan_memory - Look for an parse memory nodes
621 int __init
early_init_dt_scan_memory(unsigned long node
, const char *uname
,
622 int depth
, void *data
)
624 char *type
= of_get_flat_dt_prop(node
, "device_type", NULL
);
628 /* We are scanning "memory" nodes only */
631 * The longtrail doesn't have a device_type on the
632 * /memory node, so look for the node called /memory@0.
634 if (depth
!= 1 || strcmp(uname
, "memory@0") != 0)
636 } else if (strcmp(type
, "memory") != 0)
639 reg
= of_get_flat_dt_prop(node
, "linux,usable-memory", &l
);
641 reg
= of_get_flat_dt_prop(node
, "reg", &l
);
645 endp
= reg
+ (l
/ sizeof(__be32
));
647 pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
648 uname
, l
, reg
[0], reg
[1], reg
[2], reg
[3]);
650 while ((endp
- reg
) >= (dt_root_addr_cells
+ dt_root_size_cells
)) {
653 base
= dt_mem_next_cell(dt_root_addr_cells
, ®
);
654 size
= dt_mem_next_cell(dt_root_size_cells
, ®
);
658 pr_debug(" - %llx , %llx\n", (unsigned long long)base
,
659 (unsigned long long)size
);
661 early_init_dt_add_memory_arch(base
, size
);
667 int __init
early_init_dt_scan_chosen(unsigned long node
, const char *uname
,
668 int depth
, void *data
)
673 pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth
, uname
);
675 if (depth
!= 1 || !data
||
676 (strcmp(uname
, "chosen") != 0 && strcmp(uname
, "chosen@0") != 0))
679 early_init_dt_check_for_initrd(node
);
681 /* Retrieve command line */
682 p
= of_get_flat_dt_prop(node
, "bootargs", &l
);
683 if (p
!= NULL
&& l
> 0)
684 strlcpy(data
, p
, min((int)l
, COMMAND_LINE_SIZE
));
687 * CONFIG_CMDLINE is meant to be a default in case nothing else
688 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
689 * is set in which case we override whatever was found earlier.
691 #ifdef CONFIG_CMDLINE
692 #ifndef CONFIG_CMDLINE_FORCE
693 if (!((char *)data
)[0])
695 strlcpy(data
, CONFIG_CMDLINE
, COMMAND_LINE_SIZE
);
696 #endif /* CONFIG_CMDLINE */
698 pr_debug("Command line is: %s\n", (char*)data
);
705 * unflatten_device_tree - create tree of device_nodes from flat blob
707 * unflattens the device-tree passed by the firmware, creating the
708 * tree of struct device_node. It also fills the "name" and "type"
709 * pointers of the nodes so the normal device-tree walking functions
712 void __init
unflatten_device_tree(void)
714 __unflatten_device_tree(initial_boot_params
, &allnodes
,
715 early_init_dt_alloc_memory_arch
);
717 /* Get pointer to "/chosen" and "/aliasas" nodes for use everywhere */
718 of_alias_scan(early_init_dt_alloc_memory_arch
);
721 #endif /* CONFIG_OF_EARLY_FLATTREE */