1 // SPDX-License-Identifier: GPL-2.0
3 * Functions for working with the Flattened Device Tree data format
5 * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
6 * benh@kernel.crashing.org
9 #define pr_fmt(fmt) "OF: fdt: " fmt
11 #include <linux/crash_dump.h>
12 #include <linux/crc32.h>
13 #include <linux/kernel.h>
14 #include <linux/initrd.h>
15 #include <linux/memblock.h>
16 #include <linux/mutex.h>
18 #include <linux/of_fdt.h>
19 #include <linux/of_reserved_mem.h>
20 #include <linux/sizes.h>
21 #include <linux/string.h>
22 #include <linux/errno.h>
23 #include <linux/slab.h>
24 #include <linux/libfdt.h>
25 #include <linux/debugfs.h>
26 #include <linux/serial_core.h>
27 #include <linux/sysfs.h>
28 #include <linux/random.h>
29 #include <linux/kmemleak.h>
31 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */
34 #include "of_private.h"
37 * of_fdt_limit_memory - limit the number of regions in the /memory node
38 * @limit: maximum entries
40 * Adjust the flattened device tree to have at most 'limit' number of
41 * memory entries in the /memory node. This function may be called
42 * any time after initial_boot_param is set.
44 void __init of_fdt_limit_memory(int limit)
49 int nr_address_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
50 int nr_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
51 const __be32 *addr_prop;
52 const __be32 *size_prop;
56 root_offset = fdt_path_offset(initial_boot_params, "/");
60 addr_prop = fdt_getprop(initial_boot_params, root_offset,
61 "#address-cells", NULL);
63 nr_address_cells = fdt32_to_cpu(*addr_prop);
65 size_prop = fdt_getprop(initial_boot_params, root_offset,
68 nr_size_cells = fdt32_to_cpu(*size_prop);
70 cell_size = sizeof(uint32_t)*(nr_address_cells + nr_size_cells);
72 memory = fdt_path_offset(initial_boot_params, "/memory");
74 val = fdt_getprop(initial_boot_params, memory, "reg", &len);
75 if (len > limit*cell_size) {
76 len = limit*cell_size;
77 pr_debug("Limiting number of entries to %d\n", limit);
78 fdt_setprop(initial_boot_params, memory, "reg", val,
84 static bool of_fdt_device_is_available(const void *blob, unsigned long node)
86 const char *status = fdt_getprop(blob, node, "status", NULL);
91 if (!strcmp(status, "ok") || !strcmp(status, "okay"))
97 static void *unflatten_dt_alloc(void **mem, unsigned long size,
102 *mem = PTR_ALIGN(*mem, align);
109 static void populate_properties(const void *blob,
112 struct device_node *np,
113 const char *nodename,
116 struct property *pp, **pprev = NULL;
118 bool has_name = false;
120 pprev = &np->properties;
121 for (cur = fdt_first_property_offset(blob, offset);
123 cur = fdt_next_property_offset(blob, cur)) {
128 val = fdt_getprop_by_offset(blob, cur, &pname, &sz);
130 pr_warn("Cannot locate property at 0x%x\n", cur);
135 pr_warn("Cannot find property name at 0x%x\n", cur);
139 if (!strcmp(pname, "name"))
142 pp = unflatten_dt_alloc(mem, sizeof(struct property),
143 __alignof__(struct property));
147 /* We accept flattened tree phandles either in
148 * ePAPR-style "phandle" properties, or the
149 * legacy "linux,phandle" properties. If both
150 * appear and have different values, things
151 * will get weird. Don't do that.
153 if (!strcmp(pname, "phandle") ||
154 !strcmp(pname, "linux,phandle")) {
156 np->phandle = be32_to_cpup(val);
159 /* And we process the "ibm,phandle" property
160 * used in pSeries dynamic device tree
163 if (!strcmp(pname, "ibm,phandle"))
164 np->phandle = be32_to_cpup(val);
166 pp->name = (char *)pname;
168 pp->value = (__be32 *)val;
173 /* With version 0x10 we may not have the name property,
174 * recreate it here from the unit name if absent
177 const char *p = nodename, *ps = p, *pa = NULL;
183 else if ((*p) == '/')
191 pp = unflatten_dt_alloc(mem, sizeof(struct property) + len,
192 __alignof__(struct property));
198 memcpy(pp->value, ps, len - 1);
199 ((char *)pp->value)[len - 1] = 0;
200 pr_debug("fixed up name for %s -> %s\n",
201 nodename, (char *)pp->value);
206 static int populate_node(const void *blob,
209 struct device_node *dad,
210 struct device_node **pnp,
213 struct device_node *np;
217 pathp = fdt_get_name(blob, offset, &len);
225 np = unflatten_dt_alloc(mem, sizeof(struct device_node) + len,
226 __alignof__(struct device_node));
230 np->full_name = fn = ((char *)np) + sizeof(*np);
232 memcpy(fn, pathp, len);
236 np->sibling = dad->child;
241 populate_properties(blob, offset, mem, np, pathp, dryrun);
243 np->name = of_get_property(np, "name", NULL);
252 static void reverse_nodes(struct device_node *parent)
254 struct device_node *child, *next;
257 child = parent->child;
259 reverse_nodes(child);
261 child = child->sibling;
264 /* Reverse the nodes in the child list */
265 child = parent->child;
266 parent->child = NULL;
268 next = child->sibling;
270 child->sibling = parent->child;
271 parent->child = child;
277 * unflatten_dt_nodes - Alloc and populate a device_node from the flat tree
278 * @blob: The parent device tree blob
279 * @mem: Memory chunk to use for allocating device nodes and properties
280 * @dad: Parent struct device_node
281 * @nodepp: The device_node tree created by the call
283 * Return: The size of unflattened device tree or error code
285 static int unflatten_dt_nodes(const void *blob,
287 struct device_node *dad,
288 struct device_node **nodepp)
290 struct device_node *root;
291 int offset = 0, depth = 0, initial_depth = 0;
292 #define FDT_MAX_DEPTH 64
293 struct device_node *nps[FDT_MAX_DEPTH];
302 * We're unflattening device sub-tree if @dad is valid. There are
303 * possibly multiple nodes in the first level of depth. We need
304 * set @depth to 1 to make fdt_next_node() happy as it bails
305 * immediately when negative @depth is found. Otherwise, the device
306 * nodes except the first one won't be unflattened successfully.
309 depth = initial_depth = 1;
315 offset >= 0 && depth >= initial_depth;
316 offset = fdt_next_node(blob, offset, &depth)) {
317 if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH - 1))
320 if (!IS_ENABLED(CONFIG_OF_KOBJ) &&
321 !of_fdt_device_is_available(blob, offset))
324 ret = populate_node(blob, offset, &mem, nps[depth],
325 &nps[depth+1], dryrun);
329 if (!dryrun && nodepp && !*nodepp)
330 *nodepp = nps[depth+1];
331 if (!dryrun && !root)
335 if (offset < 0 && offset != -FDT_ERR_NOTFOUND) {
336 pr_err("Error %d processing FDT\n", offset);
341 * Reverse the child list. Some drivers assumes node order matches .dts
351 * __unflatten_device_tree - create tree of device_nodes from flat blob
352 * @blob: The blob to expand
353 * @dad: Parent device node
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
357 * @detached: if true set OF_DETACHED on @mynodes
359 * unflattens a device-tree, creating the tree of struct device_node. It also
360 * fills the "name" and "type" pointers of the nodes so the normal device-tree
361 * walking functions can be used.
363 * Return: NULL on failure or the memory chunk containing the unflattened
364 * device tree on success.
366 void *__unflatten_device_tree(const void *blob,
367 struct device_node *dad,
368 struct device_node **mynodes,
369 void *(*dt_alloc)(u64 size, u64 align),
379 pr_debug(" -> unflatten_device_tree()\n");
382 pr_debug("No device tree pointer\n");
386 pr_debug("Unflattening device tree:\n");
387 pr_debug("magic: %08x\n", fdt_magic(blob));
388 pr_debug("size: %08x\n", fdt_totalsize(blob));
389 pr_debug("version: %08x\n", fdt_version(blob));
391 if (fdt_check_header(blob)) {
392 pr_err("Invalid device tree blob header\n");
396 /* First pass, scan for size */
397 size = unflatten_dt_nodes(blob, NULL, dad, NULL);
401 size = ALIGN(size, 4);
402 pr_debug(" size is %d, allocating...\n", size);
404 /* Allocate memory for the expanded device tree */
405 mem = dt_alloc(size + 4, __alignof__(struct device_node));
409 memset(mem, 0, size);
411 *(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef);
413 pr_debug(" unflattening %p...\n", mem);
415 /* Second pass, do actual unflattening */
416 ret = unflatten_dt_nodes(blob, mem, dad, mynodes);
418 if (be32_to_cpup(mem + size) != 0xdeadbeef)
419 pr_warn("End of tree marker overwritten: %08x\n",
420 be32_to_cpup(mem + size));
425 if (detached && mynodes && *mynodes) {
426 of_node_set_flag(*mynodes, OF_DETACHED);
427 pr_debug("unflattened tree is detached\n");
430 pr_debug(" <- unflatten_device_tree()\n");
434 static void *kernel_tree_alloc(u64 size, u64 align)
436 return kzalloc(size, GFP_KERNEL);
439 static DEFINE_MUTEX(of_fdt_unflatten_mutex);
442 * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
443 * @blob: Flat device tree blob
444 * @dad: Parent device node
445 * @mynodes: The device tree created by the call
447 * unflattens the device-tree passed by the firmware, creating the
448 * tree of struct device_node. It also fills the "name" and "type"
449 * pointers of the nodes so the normal device-tree walking functions
452 * Return: NULL on failure or the memory chunk containing the unflattened
453 * device tree on success.
455 void *of_fdt_unflatten_tree(const unsigned long *blob,
456 struct device_node *dad,
457 struct device_node **mynodes)
461 mutex_lock(&of_fdt_unflatten_mutex);
462 mem = __unflatten_device_tree(blob, dad, mynodes, &kernel_tree_alloc,
464 mutex_unlock(&of_fdt_unflatten_mutex);
468 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
470 /* Everything below here references initial_boot_params directly. */
471 int __initdata dt_root_addr_cells;
472 int __initdata dt_root_size_cells;
474 void *initial_boot_params __ro_after_init;
476 #ifdef CONFIG_OF_EARLY_FLATTREE
478 static u32 of_fdt_crc32;
480 static int __init early_init_dt_reserve_memory(phys_addr_t base,
481 phys_addr_t size, bool nomap)
485 * If the memory is already reserved (by another region), we
486 * should not allow it to be marked nomap, but don't worry
487 * if the region isn't memory as it won't be mapped.
489 if (memblock_overlaps_region(&memblock.memory, base, size) &&
490 memblock_is_region_reserved(base, size))
493 return memblock_mark_nomap(base, size);
495 return memblock_reserve(base, size);
499 * __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
501 static int __init __reserved_mem_reserve_reg(unsigned long node,
504 int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
505 phys_addr_t base, size;
511 prop = of_get_flat_dt_prop(node, "reg", &len);
515 if (len && len % t_len != 0) {
516 pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
521 nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
523 while (len >= t_len) {
524 base = dt_mem_next_cell(dt_root_addr_cells, &prop);
525 size = dt_mem_next_cell(dt_root_size_cells, &prop);
528 early_init_dt_reserve_memory(base, size, nomap) == 0) {
529 pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
530 uname, &base, (unsigned long)(size / SZ_1M));
532 kmemleak_alloc_phys(base, size, 0);
535 pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
536 uname, &base, (unsigned long)(size / SZ_1M));
540 fdt_reserved_mem_save_node(node, uname, base, size);
548 * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
549 * in /reserved-memory matches the values supported by the current implementation,
550 * also check if ranges property has been provided
552 static int __init __reserved_mem_check_root(unsigned long node)
556 prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
557 if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
560 prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
561 if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
564 prop = of_get_flat_dt_prop(node, "ranges", NULL);
571 * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
573 static int __init fdt_scan_reserved_mem(void)
576 const void *fdt = initial_boot_params;
578 node = fdt_path_offset(fdt, "/reserved-memory");
582 if (__reserved_mem_check_root(node) != 0) {
583 pr_err("Reserved memory: unsupported node format, ignoring\n");
587 fdt_for_each_subnode(child, fdt, node) {
591 if (!of_fdt_device_is_available(fdt, child))
594 uname = fdt_get_name(fdt, child, NULL);
596 err = __reserved_mem_reserve_reg(child, uname);
597 if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL))
598 fdt_reserved_mem_save_node(child, uname, 0, 0);
604 * fdt_reserve_elfcorehdr() - reserves memory for elf core header
606 * This function reserves the memory occupied by an elf core header
607 * described in the device tree. This region contains all the
608 * information about primary kernel's core image and is used by a dump
609 * capture kernel to access the system memory on primary kernel.
611 static void __init fdt_reserve_elfcorehdr(void)
613 if (!IS_ENABLED(CONFIG_CRASH_DUMP) || !elfcorehdr_size)
616 if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
617 pr_warn("elfcorehdr is overlapped\n");
621 memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
623 pr_info("Reserving %llu KiB of memory at 0x%llx for elfcorehdr\n",
624 elfcorehdr_size >> 10, elfcorehdr_addr);
628 * early_init_fdt_scan_reserved_mem() - create reserved memory regions
630 * This function grabs memory from early allocator for device exclusive use
631 * defined in device tree structures. It should be called by arch specific code
632 * once the early allocator (i.e. memblock) has been fully activated.
634 void __init early_init_fdt_scan_reserved_mem(void)
639 if (!initial_boot_params)
642 /* Process header /memreserve/ fields */
644 fdt_get_mem_rsv(initial_boot_params, n, &base, &size);
647 memblock_reserve(base, size);
650 fdt_scan_reserved_mem();
651 fdt_reserve_elfcorehdr();
652 fdt_init_reserved_mem();
656 * early_init_fdt_reserve_self() - reserve the memory used by the FDT blob
658 void __init early_init_fdt_reserve_self(void)
660 if (!initial_boot_params)
663 /* Reserve the dtb region */
664 memblock_reserve(__pa(initial_boot_params),
665 fdt_totalsize(initial_boot_params));
669 * of_scan_flat_dt - scan flattened tree blob and call callback on each.
670 * @it: callback function
671 * @data: context data pointer
673 * This function is used to scan the flattened device-tree, it is
674 * used to extract the memory information at boot before we can
677 int __init of_scan_flat_dt(int (*it)(unsigned long node,
678 const char *uname, int depth,
682 const void *blob = initial_boot_params;
684 int offset, rc = 0, depth = -1;
689 for (offset = fdt_next_node(blob, -1, &depth);
690 offset >= 0 && depth >= 0 && !rc;
691 offset = fdt_next_node(blob, offset, &depth)) {
693 pathp = fdt_get_name(blob, offset, NULL);
694 rc = it(offset, pathp, depth, data);
700 * of_scan_flat_dt_subnodes - scan sub-nodes of a node call callback on each.
701 * @parent: parent node
702 * @it: callback function
703 * @data: context data pointer
705 * This function is used to scan sub-nodes of a node.
707 int __init of_scan_flat_dt_subnodes(unsigned long parent,
708 int (*it)(unsigned long node,
713 const void *blob = initial_boot_params;
716 fdt_for_each_subnode(node, blob, parent) {
720 pathp = fdt_get_name(blob, node, NULL);
721 rc = it(node, pathp, data);
729 * of_get_flat_dt_subnode_by_name - get the subnode by given name
731 * @node: the parent node
732 * @uname: the name of subnode
733 * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
736 int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
738 return fdt_subnode_offset(initial_boot_params, node, uname);
742 * of_get_flat_dt_root - find the root node in the flat blob
744 unsigned long __init of_get_flat_dt_root(void)
750 * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
752 * This function can be used within scan_flattened_dt callback to get
753 * access to properties
755 const void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
758 return fdt_getprop(initial_boot_params, node, name, size);
762 * of_fdt_is_compatible - Return true if given node from the given blob has
763 * compat in its compatible list
764 * @blob: A device tree blob
765 * @node: node to test
766 * @compat: compatible string to compare with compatible list.
768 * Return: a non-zero value on match with smaller values returned for more
769 * specific compatible values.
771 static int of_fdt_is_compatible(const void *blob,
772 unsigned long node, const char *compat)
776 unsigned long l, score = 0;
778 cp = fdt_getprop(blob, node, "compatible", &cplen);
783 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
794 * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
795 * @node: node to test
796 * @compat: compatible string to compare with compatible list.
798 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
800 return of_fdt_is_compatible(initial_boot_params, node, compat);
804 * of_flat_dt_match - Return true if node matches a list of compatible values
806 static int __init of_flat_dt_match(unsigned long node, const char *const *compat)
808 unsigned int tmp, score = 0;
814 tmp = of_fdt_is_compatible(initial_boot_params, node, *compat);
815 if (tmp && (score == 0 || (tmp < score)))
824 * of_get_flat_dt_phandle - Given a node in the flat blob, return the phandle
826 uint32_t __init of_get_flat_dt_phandle(unsigned long node)
828 return fdt_get_phandle(initial_boot_params, node);
831 const char * __init of_flat_dt_get_machine_name(void)
834 unsigned long dt_root = of_get_flat_dt_root();
836 name = of_get_flat_dt_prop(dt_root, "model", NULL);
838 name = of_get_flat_dt_prop(dt_root, "compatible", NULL);
843 * of_flat_dt_match_machine - Iterate match tables to find matching machine.
845 * @default_match: A machine specific ptr to return in case of no match.
846 * @get_next_compat: callback function to return next compatible match table.
848 * Iterate through machine match tables to find the best match for the machine
849 * compatible string in the FDT.
851 const void * __init of_flat_dt_match_machine(const void *default_match,
852 const void * (*get_next_compat)(const char * const**))
854 const void *data = NULL;
855 const void *best_data = default_match;
856 const char *const *compat;
857 unsigned long dt_root;
858 unsigned int best_score = ~1, score = 0;
860 dt_root = of_get_flat_dt_root();
861 while ((data = get_next_compat(&compat))) {
862 score = of_flat_dt_match(dt_root, compat);
863 if (score > 0 && score < best_score) {
872 pr_err("\n unrecognized device tree list:\n[ ");
874 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
877 printk("'%s' ", prop);
878 size -= strlen(prop) + 1;
879 prop += strlen(prop) + 1;
886 pr_info("Machine model: %s\n", of_flat_dt_get_machine_name());
891 static void __early_init_dt_declare_initrd(unsigned long start,
894 /* ARM64 would cause a BUG to occur here when CONFIG_DEBUG_VM is
895 * enabled since __va() is called too early. ARM64 does make use
896 * of phys_initrd_start/phys_initrd_size so we can skip this
899 if (!IS_ENABLED(CONFIG_ARM64)) {
900 initrd_start = (unsigned long)__va(start);
901 initrd_end = (unsigned long)__va(end);
902 initrd_below_start_ok = 1;
907 * early_init_dt_check_for_initrd - Decode initrd location from flat tree
908 * @node: reference to node containing initrd location ('chosen')
910 static void __init early_init_dt_check_for_initrd(unsigned long node)
916 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
919 pr_debug("Looking for initrd properties... ");
921 prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
924 start = of_read_number(prop, len/4);
926 prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
929 end = of_read_number(prop, len/4);
933 __early_init_dt_declare_initrd(start, end);
934 phys_initrd_start = start;
935 phys_initrd_size = end - start;
937 pr_debug("initrd_start=0x%llx initrd_end=0x%llx\n", start, end);
941 * early_init_dt_check_for_elfcorehdr - Decode elfcorehdr location from flat
943 * @node: reference to node containing elfcorehdr location ('chosen')
945 static void __init early_init_dt_check_for_elfcorehdr(unsigned long node)
950 if (!IS_ENABLED(CONFIG_CRASH_DUMP))
953 pr_debug("Looking for elfcorehdr property... ");
955 prop = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len);
956 if (!prop || (len < (dt_root_addr_cells + dt_root_size_cells)))
959 elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, &prop);
960 elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, &prop);
962 pr_debug("elfcorehdr_start=0x%llx elfcorehdr_size=0x%llx\n",
963 elfcorehdr_addr, elfcorehdr_size);
966 static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND;
969 * The main usage of linux,usable-memory-range is for crash dump kernel.
970 * Originally, the number of usable-memory regions is one. Now there may
971 * be two regions, low region and high region.
972 * To make compatibility with existing user-space and older kdump, the low
973 * region is always the last range of linux,usable-memory-range if exist.
975 #define MAX_USABLE_RANGES 2
978 * early_init_dt_check_for_usable_mem_range - Decode usable memory range
979 * location from flat tree
981 void __init early_init_dt_check_for_usable_mem_range(void)
983 struct memblock_region rgn[MAX_USABLE_RANGES] = {0};
984 const __be32 *prop, *endp;
986 unsigned long node = chosen_node_offset;
991 pr_debug("Looking for usable-memory-range property... ");
993 prop = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len);
994 if (!prop || (len % (dt_root_addr_cells + dt_root_size_cells)))
997 endp = prop + (len / sizeof(__be32));
998 for (i = 0; i < MAX_USABLE_RANGES && prop < endp; i++) {
999 rgn[i].base = dt_mem_next_cell(dt_root_addr_cells, &prop);
1000 rgn[i].size = dt_mem_next_cell(dt_root_size_cells, &prop);
1002 pr_debug("cap_mem_regions[%d]: base=%pa, size=%pa\n",
1003 i, &rgn[i].base, &rgn[i].size);
1006 memblock_cap_memory_range(rgn[0].base, rgn[0].size);
1007 for (i = 1; i < MAX_USABLE_RANGES && rgn[i].size; i++)
1008 memblock_add(rgn[i].base, rgn[i].size);
1011 #ifdef CONFIG_SERIAL_EARLYCON
1013 int __init early_init_dt_scan_chosen_stdout(void)
1016 const char *p, *q, *options = NULL;
1018 const struct earlycon_id *match;
1019 const void *fdt = initial_boot_params;
1022 offset = fdt_path_offset(fdt, "/chosen");
1024 offset = fdt_path_offset(fdt, "/chosen@0");
1028 p = fdt_getprop(fdt, offset, "stdout-path", &l);
1030 p = fdt_getprop(fdt, offset, "linux,stdout-path", &l);
1034 q = strchrnul(p, ':');
1039 /* Get the node specified by stdout-path */
1040 offset = fdt_path_offset_namelen(fdt, p, l);
1042 pr_warn("earlycon: stdout-path %.*s not found\n", l, p);
1046 for (match = __earlycon_table; match < __earlycon_table_end; match++) {
1047 if (!match->compatible[0])
1050 if (fdt_node_check_compatible(fdt, offset, match->compatible))
1053 ret = of_setup_earlycon(match, offset, options);
1054 if (!ret || ret == -EALREADY)
1062 * early_init_dt_scan_root - fetch the top level address and size cells
1064 int __init early_init_dt_scan_root(void)
1067 const void *fdt = initial_boot_params;
1068 int node = fdt_path_offset(fdt, "/");
1073 dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
1074 dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
1076 prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
1078 dt_root_size_cells = be32_to_cpup(prop);
1079 pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
1081 prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
1083 dt_root_addr_cells = be32_to_cpup(prop);
1084 pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
1089 u64 __init dt_mem_next_cell(int s, const __be32 **cellp)
1091 const __be32 *p = *cellp;
1094 return of_read_number(p, s);
1098 * early_init_dt_scan_memory - Look for and parse memory nodes
1100 int __init early_init_dt_scan_memory(void)
1103 const void *fdt = initial_boot_params;
1105 fdt_for_each_subnode(node, fdt, 0) {
1106 const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
1107 const __be32 *reg, *endp;
1111 /* We are scanning "memory" nodes only */
1112 if (type == NULL || strcmp(type, "memory") != 0)
1115 if (!of_fdt_device_is_available(fdt, node))
1118 reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
1120 reg = of_get_flat_dt_prop(node, "reg", &l);
1124 endp = reg + (l / sizeof(__be32));
1125 hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
1127 pr_debug("memory scan node %s, reg size %d,\n",
1128 fdt_get_name(fdt, node, NULL), l);
1130 while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
1133 base = dt_mem_next_cell(dt_root_addr_cells, ®);
1134 size = dt_mem_next_cell(dt_root_size_cells, ®);
1138 pr_debug(" - %llx, %llx\n", base, size);
1140 early_init_dt_add_memory_arch(base, size);
1145 if (memblock_mark_hotplug(base, size))
1146 pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n",
1153 int __init early_init_dt_scan_chosen(char *cmdline)
1157 const void *rng_seed;
1158 const void *fdt = initial_boot_params;
1160 node = fdt_path_offset(fdt, "/chosen");
1162 node = fdt_path_offset(fdt, "/chosen@0");
1166 chosen_node_offset = node;
1168 early_init_dt_check_for_initrd(node);
1169 early_init_dt_check_for_elfcorehdr(node);
1171 /* Retrieve command line */
1172 p = of_get_flat_dt_prop(node, "bootargs", &l);
1173 if (p != NULL && l > 0)
1174 strscpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
1177 * CONFIG_CMDLINE is meant to be a default in case nothing else
1178 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
1179 * is set in which case we override whatever was found earlier.
1181 #ifdef CONFIG_CMDLINE
1182 #if defined(CONFIG_CMDLINE_EXTEND)
1183 strlcat(cmdline, " ", COMMAND_LINE_SIZE);
1184 strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1185 #elif defined(CONFIG_CMDLINE_FORCE)
1186 strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1188 /* No arguments from boot loader, use kernel's cmdl*/
1189 if (!((char *)cmdline)[0])
1190 strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1192 #endif /* CONFIG_CMDLINE */
1194 pr_debug("Command line is: %s\n", (char *)cmdline);
1196 rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
1197 if (rng_seed && l > 0) {
1198 add_bootloader_randomness(rng_seed, l);
1200 /* try to clear seed so it won't be found. */
1201 fdt_nop_property(initial_boot_params, node, "rng-seed");
1203 /* update CRC check value */
1204 of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1205 fdt_totalsize(initial_boot_params));
1211 #ifndef MIN_MEMBLOCK_ADDR
1212 #define MIN_MEMBLOCK_ADDR __pa(PAGE_OFFSET)
1214 #ifndef MAX_MEMBLOCK_ADDR
1215 #define MAX_MEMBLOCK_ADDR ((phys_addr_t)~0)
1218 void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
1220 const u64 phys_offset = MIN_MEMBLOCK_ADDR;
1222 if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
1223 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1228 if (!PAGE_ALIGNED(base)) {
1229 size -= PAGE_SIZE - (base & ~PAGE_MASK);
1230 base = PAGE_ALIGN(base);
1234 if (base > MAX_MEMBLOCK_ADDR) {
1235 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1240 if (base + size - 1 > MAX_MEMBLOCK_ADDR) {
1241 pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
1242 ((u64)MAX_MEMBLOCK_ADDR) + 1, base + size);
1243 size = MAX_MEMBLOCK_ADDR - base + 1;
1246 if (base + size < phys_offset) {
1247 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1251 if (base < phys_offset) {
1252 pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
1254 size -= phys_offset - base;
1257 memblock_add(base, size);
1260 static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
1262 void *ptr = memblock_alloc(size, align);
1265 panic("%s: Failed to allocate %llu bytes align=0x%llx\n",
1266 __func__, size, align);
1271 bool __init early_init_dt_verify(void *params)
1276 /* check device tree validity */
1277 if (fdt_check_header(params))
1280 /* Setup flat device-tree pointer */
1281 initial_boot_params = params;
1282 of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1283 fdt_totalsize(initial_boot_params));
1288 void __init early_init_dt_scan_nodes(void)
1292 /* Initialize {size,address}-cells info */
1293 early_init_dt_scan_root();
1295 /* Retrieve various information from the /chosen node */
1296 rc = early_init_dt_scan_chosen(boot_command_line);
1298 pr_warn("No chosen node found, continuing without\n");
1300 /* Setup memory, calling early_init_dt_add_memory_arch */
1301 early_init_dt_scan_memory();
1303 /* Handle linux,usable-memory-range property */
1304 early_init_dt_check_for_usable_mem_range();
1307 bool __init early_init_dt_scan(void *params)
1311 status = early_init_dt_verify(params);
1315 early_init_dt_scan_nodes();
1320 * unflatten_device_tree - create tree of device_nodes from flat blob
1322 * unflattens the device-tree passed by the firmware, creating the
1323 * tree of struct device_node. It also fills the "name" and "type"
1324 * pointers of the nodes so the normal device-tree walking functions
1327 void __init unflatten_device_tree(void)
1329 __unflatten_device_tree(initial_boot_params, NULL, &of_root,
1330 early_init_dt_alloc_memory_arch, false);
1332 /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
1333 of_alias_scan(early_init_dt_alloc_memory_arch);
1335 unittest_unflatten_overlay_base();
1339 * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob
1341 * Copies and unflattens the device-tree passed by the firmware, creating the
1342 * tree of struct device_node. It also fills the "name" and "type"
1343 * pointers of the nodes so the normal device-tree walking functions
1344 * can be used. This should only be used when the FDT memory has not been
1345 * reserved such is the case when the FDT is built-in to the kernel init
1346 * section. If the FDT memory is reserved already then unflatten_device_tree
1347 * should be used instead.
1349 void __init unflatten_and_copy_device_tree(void)
1354 if (!initial_boot_params) {
1355 pr_warn("No valid device tree found, continuing without\n");
1359 size = fdt_totalsize(initial_boot_params);
1360 dt = early_init_dt_alloc_memory_arch(size,
1361 roundup_pow_of_two(FDT_V17_SIZE));
1364 memcpy(dt, initial_boot_params, size);
1365 initial_boot_params = dt;
1367 unflatten_device_tree();
1371 static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj,
1372 struct bin_attribute *bin_attr,
1373 char *buf, loff_t off, size_t count)
1375 memcpy(buf, initial_boot_params + off, count);
1379 static int __init of_fdt_raw_init(void)
1381 static struct bin_attribute of_fdt_raw_attr =
1382 __BIN_ATTR(fdt, S_IRUSR, of_fdt_raw_read, NULL, 0);
1384 if (!initial_boot_params)
1387 if (of_fdt_crc32 != crc32_be(~0, initial_boot_params,
1388 fdt_totalsize(initial_boot_params))) {
1389 pr_warn("not creating '/sys/firmware/fdt': CRC check failed\n");
1392 of_fdt_raw_attr.size = fdt_totalsize(initial_boot_params);
1393 return sysfs_create_bin_file(firmware_kobj, &of_fdt_raw_attr);
1395 late_initcall(of_fdt_raw_init);
1398 #endif /* CONFIG_OF_EARLY_FLATTREE */