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
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>
30 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */
33 #include "of_private.h"
36 * of_fdt_limit_memory - limit the number of regions in the /memory node
37 * @limit: maximum entries
39 * Adjust the flattened device tree to have at most 'limit' number of
40 * memory entries in the /memory node. This function may be called
41 * any time after initial_boot_param is set.
43 void __init of_fdt_limit_memory(int limit)
48 int nr_address_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
49 int nr_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
50 const __be32 *addr_prop;
51 const __be32 *size_prop;
55 root_offset = fdt_path_offset(initial_boot_params, "/");
59 addr_prop = fdt_getprop(initial_boot_params, root_offset,
60 "#address-cells", NULL);
62 nr_address_cells = fdt32_to_cpu(*addr_prop);
64 size_prop = fdt_getprop(initial_boot_params, root_offset,
67 nr_size_cells = fdt32_to_cpu(*size_prop);
69 cell_size = sizeof(uint32_t)*(nr_address_cells + nr_size_cells);
71 memory = fdt_path_offset(initial_boot_params, "/memory");
73 val = fdt_getprop(initial_boot_params, memory, "reg", &len);
74 if (len > limit*cell_size) {
75 len = limit*cell_size;
76 pr_debug("Limiting number of entries to %d\n", limit);
77 fdt_setprop(initial_boot_params, memory, "reg", val,
83 static bool of_fdt_device_is_available(const void *blob, unsigned long node)
85 const char *status = fdt_getprop(blob, node, "status", NULL);
90 if (!strcmp(status, "ok") || !strcmp(status, "okay"))
96 static void *unflatten_dt_alloc(void **mem, unsigned long size,
101 *mem = PTR_ALIGN(*mem, align);
108 static void populate_properties(const void *blob,
111 struct device_node *np,
112 const char *nodename,
115 struct property *pp, **pprev = NULL;
117 bool has_name = false;
119 pprev = &np->properties;
120 for (cur = fdt_first_property_offset(blob, offset);
122 cur = fdt_next_property_offset(blob, cur)) {
127 val = fdt_getprop_by_offset(blob, cur, &pname, &sz);
129 pr_warn("Cannot locate property at 0x%x\n", cur);
134 pr_warn("Cannot find property name at 0x%x\n", cur);
138 if (!strcmp(pname, "name"))
141 pp = unflatten_dt_alloc(mem, sizeof(struct property),
142 __alignof__(struct property));
146 /* We accept flattened tree phandles either in
147 * ePAPR-style "phandle" properties, or the
148 * legacy "linux,phandle" properties. If both
149 * appear and have different values, things
150 * will get weird. Don't do that.
152 if (!strcmp(pname, "phandle") ||
153 !strcmp(pname, "linux,phandle")) {
155 np->phandle = be32_to_cpup(val);
158 /* And we process the "ibm,phandle" property
159 * used in pSeries dynamic device tree
162 if (!strcmp(pname, "ibm,phandle"))
163 np->phandle = be32_to_cpup(val);
165 pp->name = (char *)pname;
167 pp->value = (__be32 *)val;
172 /* With version 0x10 we may not have the name property,
173 * recreate it here from the unit name if absent
176 const char *p = nodename, *ps = p, *pa = NULL;
182 else if ((*p) == '/')
190 pp = unflatten_dt_alloc(mem, sizeof(struct property) + len,
191 __alignof__(struct property));
197 memcpy(pp->value, ps, len - 1);
198 ((char *)pp->value)[len - 1] = 0;
199 pr_debug("fixed up name for %s -> %s\n",
200 nodename, (char *)pp->value);
205 static int populate_node(const void *blob,
208 struct device_node *dad,
209 struct device_node **pnp,
212 struct device_node *np;
216 pathp = fdt_get_name(blob, offset, &len);
224 np = unflatten_dt_alloc(mem, sizeof(struct device_node) + len,
225 __alignof__(struct device_node));
229 np->full_name = fn = ((char *)np) + sizeof(*np);
231 memcpy(fn, pathp, len);
235 np->sibling = dad->child;
240 populate_properties(blob, offset, mem, np, pathp, dryrun);
242 np->name = of_get_property(np, "name", NULL);
251 static void reverse_nodes(struct device_node *parent)
253 struct device_node *child, *next;
256 child = parent->child;
258 reverse_nodes(child);
260 child = child->sibling;
263 /* Reverse the nodes in the child list */
264 child = parent->child;
265 parent->child = NULL;
267 next = child->sibling;
269 child->sibling = parent->child;
270 parent->child = child;
276 * unflatten_dt_nodes - Alloc and populate a device_node from the flat tree
277 * @blob: The parent device tree blob
278 * @mem: Memory chunk to use for allocating device nodes and properties
279 * @dad: Parent struct device_node
280 * @nodepp: The device_node tree created by the call
282 * Return: The size of unflattened device tree or error code
284 static int unflatten_dt_nodes(const void *blob,
286 struct device_node *dad,
287 struct device_node **nodepp)
289 struct device_node *root;
290 int offset = 0, depth = 0, initial_depth = 0;
291 #define FDT_MAX_DEPTH 64
292 struct device_node *nps[FDT_MAX_DEPTH];
301 * We're unflattening device sub-tree if @dad is valid. There are
302 * possibly multiple nodes in the first level of depth. We need
303 * set @depth to 1 to make fdt_next_node() happy as it bails
304 * immediately when negative @depth is found. Otherwise, the device
305 * nodes except the first one won't be unflattened successfully.
308 depth = initial_depth = 1;
314 offset >= 0 && depth >= initial_depth;
315 offset = fdt_next_node(blob, offset, &depth)) {
316 if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH - 1))
319 if (!IS_ENABLED(CONFIG_OF_KOBJ) &&
320 !of_fdt_device_is_available(blob, offset))
323 ret = populate_node(blob, offset, &mem, nps[depth],
324 &nps[depth+1], dryrun);
328 if (!dryrun && nodepp && !*nodepp)
329 *nodepp = nps[depth+1];
330 if (!dryrun && !root)
334 if (offset < 0 && offset != -FDT_ERR_NOTFOUND) {
335 pr_err("Error %d processing FDT\n", offset);
340 * Reverse the child list. Some drivers assumes node order matches .dts
350 * __unflatten_device_tree - create tree of device_nodes from flat blob
351 * @blob: The blob to expand
352 * @dad: Parent device node
353 * @mynodes: The device_node tree created by the call
354 * @dt_alloc: An allocator that provides a virtual address to memory
355 * for the resulting tree
356 * @detached: if true set OF_DETACHED on @mynodes
358 * unflattens a device-tree, creating the tree of struct device_node. It also
359 * fills the "name" and "type" pointers of the nodes so the normal device-tree
360 * walking functions can be used.
362 * Return: NULL on failure or the memory chunk containing the unflattened
363 * device tree on success.
365 void *__unflatten_device_tree(const void *blob,
366 struct device_node *dad,
367 struct device_node **mynodes,
368 void *(*dt_alloc)(u64 size, u64 align),
378 pr_debug(" -> unflatten_device_tree()\n");
381 pr_debug("No device tree pointer\n");
385 pr_debug("Unflattening device tree:\n");
386 pr_debug("magic: %08x\n", fdt_magic(blob));
387 pr_debug("size: %08x\n", fdt_totalsize(blob));
388 pr_debug("version: %08x\n", fdt_version(blob));
390 if (fdt_check_header(blob)) {
391 pr_err("Invalid device tree blob header\n");
395 /* First pass, scan for size */
396 size = unflatten_dt_nodes(blob, NULL, dad, NULL);
400 size = ALIGN(size, 4);
401 pr_debug(" size is %d, allocating...\n", size);
403 /* Allocate memory for the expanded device tree */
404 mem = dt_alloc(size + 4, __alignof__(struct device_node));
408 memset(mem, 0, size);
410 *(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef);
412 pr_debug(" unflattening %p...\n", mem);
414 /* Second pass, do actual unflattening */
415 ret = unflatten_dt_nodes(blob, mem, dad, mynodes);
417 if (be32_to_cpup(mem + size) != 0xdeadbeef)
418 pr_warn("End of tree marker overwritten: %08x\n",
419 be32_to_cpup(mem + size));
424 if (detached && mynodes && *mynodes) {
425 of_node_set_flag(*mynodes, OF_DETACHED);
426 pr_debug("unflattened tree is detached\n");
429 pr_debug(" <- unflatten_device_tree()\n");
433 static void *kernel_tree_alloc(u64 size, u64 align)
435 return kzalloc(size, GFP_KERNEL);
438 static DEFINE_MUTEX(of_fdt_unflatten_mutex);
441 * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
442 * @blob: Flat device tree blob
443 * @dad: Parent device node
444 * @mynodes: The device tree created by the call
446 * unflattens the device-tree passed by the firmware, creating the
447 * tree of struct device_node. It also fills the "name" and "type"
448 * pointers of the nodes so the normal device-tree walking functions
451 * Return: NULL on failure or the memory chunk containing the unflattened
452 * device tree on success.
454 void *of_fdt_unflatten_tree(const unsigned long *blob,
455 struct device_node *dad,
456 struct device_node **mynodes)
460 mutex_lock(&of_fdt_unflatten_mutex);
461 mem = __unflatten_device_tree(blob, dad, mynodes, &kernel_tree_alloc,
463 mutex_unlock(&of_fdt_unflatten_mutex);
467 EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
469 /* Everything below here references initial_boot_params directly. */
470 int __initdata dt_root_addr_cells;
471 int __initdata dt_root_size_cells;
473 void *initial_boot_params __ro_after_init;
475 #ifdef CONFIG_OF_EARLY_FLATTREE
477 static u32 of_fdt_crc32;
479 static int __init early_init_dt_reserve_memory(phys_addr_t base,
480 phys_addr_t size, bool nomap)
484 * If the memory is already reserved (by another region), we
485 * should not allow it to be marked nomap, but don't worry
486 * if the region isn't memory as it won't be mapped.
488 if (memblock_overlaps_region(&memblock.memory, base, size) &&
489 memblock_is_region_reserved(base, size))
492 return memblock_mark_nomap(base, size);
494 return memblock_reserve(base, size);
498 * __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
500 static int __init __reserved_mem_reserve_reg(unsigned long node,
503 int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
504 phys_addr_t base, size;
510 prop = of_get_flat_dt_prop(node, "reg", &len);
514 if (len && len % t_len != 0) {
515 pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
520 nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
522 while (len >= t_len) {
523 base = dt_mem_next_cell(dt_root_addr_cells, &prop);
524 size = dt_mem_next_cell(dt_root_size_cells, &prop);
527 early_init_dt_reserve_memory(base, size, nomap) == 0)
528 pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
529 uname, &base, (unsigned long)(size / SZ_1M));
531 pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
532 uname, &base, (unsigned long)(size / SZ_1M));
536 fdt_reserved_mem_save_node(node, uname, base, size);
544 * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
545 * in /reserved-memory matches the values supported by the current implementation,
546 * also check if ranges property has been provided
548 static int __init __reserved_mem_check_root(unsigned long node)
552 prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
553 if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
556 prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
557 if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
560 prop = of_get_flat_dt_prop(node, "ranges", NULL);
567 * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
569 static int __init fdt_scan_reserved_mem(void)
572 const void *fdt = initial_boot_params;
574 node = fdt_path_offset(fdt, "/reserved-memory");
578 if (__reserved_mem_check_root(node) != 0) {
579 pr_err("Reserved memory: unsupported node format, ignoring\n");
583 fdt_for_each_subnode(child, fdt, node) {
587 if (!of_fdt_device_is_available(fdt, child))
590 uname = fdt_get_name(fdt, child, NULL);
592 err = __reserved_mem_reserve_reg(child, uname);
593 if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL))
594 fdt_reserved_mem_save_node(child, uname, 0, 0);
600 * fdt_reserve_elfcorehdr() - reserves memory for elf core header
602 * This function reserves the memory occupied by an elf core header
603 * described in the device tree. This region contains all the
604 * information about primary kernel's core image and is used by a dump
605 * capture kernel to access the system memory on primary kernel.
607 static void __init fdt_reserve_elfcorehdr(void)
609 if (!IS_ENABLED(CONFIG_CRASH_DUMP) || !elfcorehdr_size)
612 if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
613 pr_warn("elfcorehdr is overlapped\n");
617 memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
619 pr_info("Reserving %llu KiB of memory at 0x%llx for elfcorehdr\n",
620 elfcorehdr_size >> 10, elfcorehdr_addr);
624 * early_init_fdt_scan_reserved_mem() - create reserved memory regions
626 * This function grabs memory from early allocator for device exclusive use
627 * defined in device tree structures. It should be called by arch specific code
628 * once the early allocator (i.e. memblock) has been fully activated.
630 void __init early_init_fdt_scan_reserved_mem(void)
635 if (!initial_boot_params)
638 fdt_scan_reserved_mem();
639 fdt_reserve_elfcorehdr();
641 /* Process header /memreserve/ fields */
643 fdt_get_mem_rsv(initial_boot_params, n, &base, &size);
646 memblock_reserve(base, size);
649 fdt_init_reserved_mem();
653 * early_init_fdt_reserve_self() - reserve the memory used by the FDT blob
655 void __init early_init_fdt_reserve_self(void)
657 if (!initial_boot_params)
660 /* Reserve the dtb region */
661 memblock_reserve(__pa(initial_boot_params),
662 fdt_totalsize(initial_boot_params));
666 * of_scan_flat_dt - scan flattened tree blob and call callback on each.
667 * @it: callback function
668 * @data: context data pointer
670 * This function is used to scan the flattened device-tree, it is
671 * used to extract the memory information at boot before we can
674 int __init of_scan_flat_dt(int (*it)(unsigned long node,
675 const char *uname, int depth,
679 const void *blob = initial_boot_params;
681 int offset, rc = 0, depth = -1;
686 for (offset = fdt_next_node(blob, -1, &depth);
687 offset >= 0 && depth >= 0 && !rc;
688 offset = fdt_next_node(blob, offset, &depth)) {
690 pathp = fdt_get_name(blob, offset, NULL);
691 rc = it(offset, pathp, depth, data);
697 * of_scan_flat_dt_subnodes - scan sub-nodes of a node call callback on each.
698 * @parent: parent node
699 * @it: callback function
700 * @data: context data pointer
702 * This function is used to scan sub-nodes of a node.
704 int __init of_scan_flat_dt_subnodes(unsigned long parent,
705 int (*it)(unsigned long node,
710 const void *blob = initial_boot_params;
713 fdt_for_each_subnode(node, blob, parent) {
717 pathp = fdt_get_name(blob, node, NULL);
718 rc = it(node, pathp, data);
726 * of_get_flat_dt_subnode_by_name - get the subnode by given name
728 * @node: the parent node
729 * @uname: the name of subnode
730 * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
733 int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
735 return fdt_subnode_offset(initial_boot_params, node, uname);
739 * of_get_flat_dt_root - find the root node in the flat blob
741 unsigned long __init of_get_flat_dt_root(void)
747 * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
749 * This function can be used within scan_flattened_dt callback to get
750 * access to properties
752 const void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
755 return fdt_getprop(initial_boot_params, node, name, size);
759 * of_fdt_is_compatible - Return true if given node from the given blob has
760 * compat in its compatible list
761 * @blob: A device tree blob
762 * @node: node to test
763 * @compat: compatible string to compare with compatible list.
765 * Return: a non-zero value on match with smaller values returned for more
766 * specific compatible values.
768 static int of_fdt_is_compatible(const void *blob,
769 unsigned long node, const char *compat)
773 unsigned long l, score = 0;
775 cp = fdt_getprop(blob, node, "compatible", &cplen);
780 if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
791 * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
792 * @node: node to test
793 * @compat: compatible string to compare with compatible list.
795 int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
797 return of_fdt_is_compatible(initial_boot_params, node, compat);
801 * of_flat_dt_match - Return true if node matches a list of compatible values
803 static int __init of_flat_dt_match(unsigned long node, const char *const *compat)
805 unsigned int tmp, score = 0;
811 tmp = of_fdt_is_compatible(initial_boot_params, node, *compat);
812 if (tmp && (score == 0 || (tmp < score)))
821 * of_get_flat_dt_phandle - Given a node in the flat blob, return the phandle
823 uint32_t __init of_get_flat_dt_phandle(unsigned long node)
825 return fdt_get_phandle(initial_boot_params, node);
828 const char * __init of_flat_dt_get_machine_name(void)
831 unsigned long dt_root = of_get_flat_dt_root();
833 name = of_get_flat_dt_prop(dt_root, "model", NULL);
835 name = of_get_flat_dt_prop(dt_root, "compatible", NULL);
840 * of_flat_dt_match_machine - Iterate match tables to find matching machine.
842 * @default_match: A machine specific ptr to return in case of no match.
843 * @get_next_compat: callback function to return next compatible match table.
845 * Iterate through machine match tables to find the best match for the machine
846 * compatible string in the FDT.
848 const void * __init of_flat_dt_match_machine(const void *default_match,
849 const void * (*get_next_compat)(const char * const**))
851 const void *data = NULL;
852 const void *best_data = default_match;
853 const char *const *compat;
854 unsigned long dt_root;
855 unsigned int best_score = ~1, score = 0;
857 dt_root = of_get_flat_dt_root();
858 while ((data = get_next_compat(&compat))) {
859 score = of_flat_dt_match(dt_root, compat);
860 if (score > 0 && score < best_score) {
869 pr_err("\n unrecognized device tree list:\n[ ");
871 prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
874 printk("'%s' ", prop);
875 size -= strlen(prop) + 1;
876 prop += strlen(prop) + 1;
883 pr_info("Machine model: %s\n", of_flat_dt_get_machine_name());
888 static void __early_init_dt_declare_initrd(unsigned long start,
892 * __va() is not yet available this early on some platforms. In that
893 * case, the platform uses phys_initrd_start/phys_initrd_size instead
894 * and does the VA conversion itself.
896 if (!IS_ENABLED(CONFIG_ARM64) &&
897 !(IS_ENABLED(CONFIG_RISCV) && IS_ENABLED(CONFIG_64BIT))) {
898 initrd_start = (unsigned long)__va(start);
899 initrd_end = (unsigned long)__va(end);
900 initrd_below_start_ok = 1;
905 * early_init_dt_check_for_initrd - Decode initrd location from flat tree
906 * @node: reference to node containing initrd location ('chosen')
908 static void __init early_init_dt_check_for_initrd(unsigned long node)
914 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
917 pr_debug("Looking for initrd properties... ");
919 prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
922 start = of_read_number(prop, len/4);
924 prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
927 end = of_read_number(prop, len/4);
931 __early_init_dt_declare_initrd(start, end);
932 phys_initrd_start = start;
933 phys_initrd_size = end - start;
935 pr_debug("initrd_start=0x%llx initrd_end=0x%llx\n", start, end);
939 * early_init_dt_check_for_elfcorehdr - Decode elfcorehdr location from flat
941 * @node: reference to node containing elfcorehdr location ('chosen')
943 static void __init early_init_dt_check_for_elfcorehdr(unsigned long node)
948 if (!IS_ENABLED(CONFIG_CRASH_DUMP))
951 pr_debug("Looking for elfcorehdr property... ");
953 prop = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len);
954 if (!prop || (len < (dt_root_addr_cells + dt_root_size_cells)))
957 elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, &prop);
958 elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, &prop);
960 pr_debug("elfcorehdr_start=0x%llx elfcorehdr_size=0x%llx\n",
961 elfcorehdr_addr, elfcorehdr_size);
964 static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND;
967 * The main usage of linux,usable-memory-range is for crash dump kernel.
968 * Originally, the number of usable-memory regions is one. Now there may
969 * be two regions, low region and high region.
970 * To make compatibility with existing user-space and older kdump, the low
971 * region is always the last range of linux,usable-memory-range if exist.
973 #define MAX_USABLE_RANGES 2
976 * early_init_dt_check_for_usable_mem_range - Decode usable memory range
977 * location from flat tree
979 void __init early_init_dt_check_for_usable_mem_range(void)
981 struct memblock_region rgn[MAX_USABLE_RANGES] = {0};
982 const __be32 *prop, *endp;
984 unsigned long node = chosen_node_offset;
989 pr_debug("Looking for usable-memory-range property... ");
991 prop = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len);
992 if (!prop || (len % (dt_root_addr_cells + dt_root_size_cells)))
995 endp = prop + (len / sizeof(__be32));
996 for (i = 0; i < MAX_USABLE_RANGES && prop < endp; i++) {
997 rgn[i].base = dt_mem_next_cell(dt_root_addr_cells, &prop);
998 rgn[i].size = dt_mem_next_cell(dt_root_size_cells, &prop);
1000 pr_debug("cap_mem_regions[%d]: base=%pa, size=%pa\n",
1001 i, &rgn[i].base, &rgn[i].size);
1004 memblock_cap_memory_range(rgn[0].base, rgn[0].size);
1005 for (i = 1; i < MAX_USABLE_RANGES && rgn[i].size; i++)
1006 memblock_add(rgn[i].base, rgn[i].size);
1009 #ifdef CONFIG_SERIAL_EARLYCON
1011 int __init early_init_dt_scan_chosen_stdout(void)
1014 const char *p, *q, *options = NULL;
1016 const struct earlycon_id *match;
1017 const void *fdt = initial_boot_params;
1020 offset = fdt_path_offset(fdt, "/chosen");
1022 offset = fdt_path_offset(fdt, "/chosen@0");
1026 p = fdt_getprop(fdt, offset, "stdout-path", &l);
1028 p = fdt_getprop(fdt, offset, "linux,stdout-path", &l);
1032 q = strchrnul(p, ':');
1037 /* Get the node specified by stdout-path */
1038 offset = fdt_path_offset_namelen(fdt, p, l);
1040 pr_warn("earlycon: stdout-path %.*s not found\n", l, p);
1044 for (match = __earlycon_table; match < __earlycon_table_end; match++) {
1045 if (!match->compatible[0])
1048 if (fdt_node_check_compatible(fdt, offset, match->compatible))
1051 ret = of_setup_earlycon(match, offset, options);
1052 if (!ret || ret == -EALREADY)
1060 * early_init_dt_scan_root - fetch the top level address and size cells
1062 int __init early_init_dt_scan_root(void)
1065 const void *fdt = initial_boot_params;
1066 int node = fdt_path_offset(fdt, "/");
1071 dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
1072 dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
1074 prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
1076 dt_root_size_cells = be32_to_cpup(prop);
1077 pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
1079 prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
1081 dt_root_addr_cells = be32_to_cpup(prop);
1082 pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
1087 u64 __init dt_mem_next_cell(int s, const __be32 **cellp)
1089 const __be32 *p = *cellp;
1092 return of_read_number(p, s);
1096 * early_init_dt_scan_memory - Look for and parse memory nodes
1098 int __init early_init_dt_scan_memory(void)
1100 int node, found_memory = 0;
1101 const void *fdt = initial_boot_params;
1103 fdt_for_each_subnode(node, fdt, 0) {
1104 const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
1105 const __be32 *reg, *endp;
1109 /* We are scanning "memory" nodes only */
1110 if (type == NULL || strcmp(type, "memory") != 0)
1113 if (!of_fdt_device_is_available(fdt, node))
1116 reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
1118 reg = of_get_flat_dt_prop(node, "reg", &l);
1122 endp = reg + (l / sizeof(__be32));
1123 hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
1125 pr_debug("memory scan node %s, reg size %d,\n",
1126 fdt_get_name(fdt, node, NULL), l);
1128 while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
1131 base = dt_mem_next_cell(dt_root_addr_cells, ®);
1132 size = dt_mem_next_cell(dt_root_size_cells, ®);
1136 pr_debug(" - %llx, %llx\n", base, size);
1138 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",
1150 return found_memory;
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");
1164 /* Handle the cmdline config options even if no /chosen node */
1165 goto handle_cmdline;
1167 chosen_node_offset = node;
1169 early_init_dt_check_for_initrd(node);
1170 early_init_dt_check_for_elfcorehdr(node);
1172 rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
1173 if (rng_seed && l > 0) {
1174 add_bootloader_randomness(rng_seed, l);
1176 /* try to clear seed so it won't be found. */
1177 fdt_nop_property(initial_boot_params, node, "rng-seed");
1179 /* update CRC check value */
1180 of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1181 fdt_totalsize(initial_boot_params));
1184 /* Retrieve command line */
1185 p = of_get_flat_dt_prop(node, "bootargs", &l);
1186 if (p != NULL && l > 0)
1187 strscpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
1191 * CONFIG_CMDLINE is meant to be a default in case nothing else
1192 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
1193 * is set in which case we override whatever was found earlier.
1195 #ifdef CONFIG_CMDLINE
1196 #if defined(CONFIG_CMDLINE_EXTEND)
1197 strlcat(cmdline, " ", COMMAND_LINE_SIZE);
1198 strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1199 #elif defined(CONFIG_CMDLINE_FORCE)
1200 strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1202 /* No arguments from boot loader, use kernel's cmdl*/
1203 if (!((char *)cmdline)[0])
1204 strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
1206 #endif /* CONFIG_CMDLINE */
1208 pr_debug("Command line is: %s\n", (char *)cmdline);
1213 #ifndef MIN_MEMBLOCK_ADDR
1214 #define MIN_MEMBLOCK_ADDR __pa(PAGE_OFFSET)
1216 #ifndef MAX_MEMBLOCK_ADDR
1217 #define MAX_MEMBLOCK_ADDR ((phys_addr_t)~0)
1220 void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
1222 const u64 phys_offset = MIN_MEMBLOCK_ADDR;
1224 if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
1225 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1230 if (!PAGE_ALIGNED(base)) {
1231 size -= PAGE_SIZE - (base & ~PAGE_MASK);
1232 base = PAGE_ALIGN(base);
1236 if (base > MAX_MEMBLOCK_ADDR) {
1237 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1242 if (base + size - 1 > MAX_MEMBLOCK_ADDR) {
1243 pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
1244 ((u64)MAX_MEMBLOCK_ADDR) + 1, base + size);
1245 size = MAX_MEMBLOCK_ADDR - base + 1;
1248 if (base + size < phys_offset) {
1249 pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
1253 if (base < phys_offset) {
1254 pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
1256 size -= phys_offset - base;
1259 memblock_add(base, size);
1262 static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
1264 void *ptr = memblock_alloc(size, align);
1267 panic("%s: Failed to allocate %llu bytes align=0x%llx\n",
1268 __func__, size, align);
1273 bool __init early_init_dt_verify(void *params)
1278 /* check device tree validity */
1279 if (fdt_check_header(params))
1282 /* Setup flat device-tree pointer */
1283 initial_boot_params = params;
1284 of_fdt_crc32 = crc32_be(~0, initial_boot_params,
1285 fdt_totalsize(initial_boot_params));
1290 void __init early_init_dt_scan_nodes(void)
1294 /* Initialize {size,address}-cells info */
1295 early_init_dt_scan_root();
1297 /* Retrieve various information from the /chosen node */
1298 rc = early_init_dt_scan_chosen(boot_command_line);
1300 pr_warn("No chosen node found, continuing without\n");
1302 /* Setup memory, calling early_init_dt_add_memory_arch */
1303 early_init_dt_scan_memory();
1305 /* Handle linux,usable-memory-range property */
1306 early_init_dt_check_for_usable_mem_range();
1309 bool __init early_init_dt_scan(void *params)
1313 status = early_init_dt_verify(params);
1317 early_init_dt_scan_nodes();
1322 * unflatten_device_tree - create tree of device_nodes from flat blob
1324 * unflattens the device-tree passed by the firmware, creating the
1325 * tree of struct device_node. It also fills the "name" and "type"
1326 * pointers of the nodes so the normal device-tree walking functions
1329 void __init unflatten_device_tree(void)
1331 __unflatten_device_tree(initial_boot_params, NULL, &of_root,
1332 early_init_dt_alloc_memory_arch, false);
1334 /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
1335 of_alias_scan(early_init_dt_alloc_memory_arch);
1337 unittest_unflatten_overlay_base();
1341 * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob
1343 * Copies and unflattens the device-tree passed by the firmware, creating the
1344 * tree of struct device_node. It also fills the "name" and "type"
1345 * pointers of the nodes so the normal device-tree walking functions
1346 * can be used. This should only be used when the FDT memory has not been
1347 * reserved such is the case when the FDT is built-in to the kernel init
1348 * section. If the FDT memory is reserved already then unflatten_device_tree
1349 * should be used instead.
1351 void __init unflatten_and_copy_device_tree(void)
1356 if (!initial_boot_params) {
1357 pr_warn("No valid device tree found, continuing without\n");
1361 size = fdt_totalsize(initial_boot_params);
1362 dt = early_init_dt_alloc_memory_arch(size,
1363 roundup_pow_of_two(FDT_V17_SIZE));
1366 memcpy(dt, initial_boot_params, size);
1367 initial_boot_params = dt;
1369 unflatten_device_tree();
1373 static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj,
1374 struct bin_attribute *bin_attr,
1375 char *buf, loff_t off, size_t count)
1377 memcpy(buf, initial_boot_params + off, count);
1381 static int __init of_fdt_raw_init(void)
1383 static struct bin_attribute of_fdt_raw_attr =
1384 __BIN_ATTR(fdt, S_IRUSR, of_fdt_raw_read, NULL, 0);
1386 if (!initial_boot_params)
1389 if (of_fdt_crc32 != crc32_be(~0, initial_boot_params,
1390 fdt_totalsize(initial_boot_params))) {
1391 pr_warn("not creating '/sys/firmware/fdt': CRC check failed\n");
1394 of_fdt_raw_attr.size = fdt_totalsize(initial_boot_params);
1395 return sysfs_create_bin_file(firmware_kobj, &of_fdt_raw_attr);
1397 late_initcall(of_fdt_raw_init);
1400 #endif /* CONFIG_OF_EARLY_FLATTREE */