1/*
2 * Functions for working with the Flattened Device Tree data format
3 *
4 * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
5 * benh@kernel.crashing.org
6 *
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.
10 */
11
12#include <linux/kernel.h>
13#include <linux/initrd.h>
14#include <linux/of.h>
15#include <linux/of_fdt.h>
16#include <linux/string.h>
17#include <linux/errno.h>
18
19#ifdef CONFIG_PPC
20#include <asm/machdep.h>
21#endif /* CONFIG_PPC */
22
23#include <asm/page.h>
24
25int __initdata dt_root_addr_cells;
26int __initdata dt_root_size_cells;
27
28struct boot_param_header *initial_boot_params;
29
30char *find_flat_dt_string(u32 offset)
31{
32	return ((char *)initial_boot_params) +
33		be32_to_cpu(initial_boot_params->off_dt_strings) + offset;
34}
35
36/**
37 * of_scan_flat_dt - scan flattened tree blob and call callback on each.
38 * @it: callback function
39 * @data: context data pointer
40 *
41 * This function is used to scan the flattened device-tree, it is
42 * used to extract the memory information at boot before we can
43 * unflatten the tree
44 */
45int __init of_scan_flat_dt(int (*it)(unsigned long node,
46				     const char *uname, int depth,
47				     void *data),
48			   void *data)
49{
50	unsigned long p = ((unsigned long)initial_boot_params) +
51		be32_to_cpu(initial_boot_params->off_dt_struct);
52	int rc = 0;
53	int depth = -1;
54
55	do {
56		u32 tag = be32_to_cpup((__be32 *)p);
57		char *pathp;
58
59		p += 4;
60		if (tag == OF_DT_END_NODE) {
61			depth--;
62			continue;
63		}
64		if (tag == OF_DT_NOP)
65			continue;
66		if (tag == OF_DT_END)
67			break;
68		if (tag == OF_DT_PROP) {
69			u32 sz = be32_to_cpup((__be32 *)p);
70			p += 8;
71			if (be32_to_cpu(initial_boot_params->version) < 0x10)
72				p = ALIGN(p, sz >= 8 ? 8 : 4);
73			p += sz;
74			p = ALIGN(p, 4);
75			continue;
76		}
77		if (tag != OF_DT_BEGIN_NODE) {
78			pr_err("Invalid tag %x in flat device tree!\n", tag);
79			return -EINVAL;
80		}
81		depth++;
82		pathp = (char *)p;
83		p = ALIGN(p + strlen(pathp) + 1, 4);
84		if ((*pathp) == '/') {
85			char *lp, *np;
86			for (lp = NULL, np = pathp; *np; np++)
87				if ((*np) == '/')
88					lp = np+1;
89			if (lp != NULL)
90				pathp = lp;
91		}
92		rc = it(p, pathp, depth, data);
93		if (rc != 0)
94			break;
95	} while (1);
96
97	return rc;
98}
99
100/**
101 * of_get_flat_dt_root - find the root node in the flat blob
102 */
103unsigned long __init of_get_flat_dt_root(void)
104{
105	unsigned long p = ((unsigned long)initial_boot_params) +
106		be32_to_cpu(initial_boot_params->off_dt_struct);
107
108	while (be32_to_cpup((__be32 *)p) == OF_DT_NOP)
109		p += 4;
110	BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE);
111	p += 4;
112	return ALIGN(p + strlen((char *)p) + 1, 4);
113}
114
115/**
116 * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
117 *
118 * This function can be used within scan_flattened_dt callback to get
119 * access to properties
120 */
121void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
122				 unsigned long *size)
123{
124	unsigned long p = node;
125
126	do {
127		u32 tag = be32_to_cpup((__be32 *)p);
128		u32 sz, noff;
129		const char *nstr;
130
131		p += 4;
132		if (tag == OF_DT_NOP)
133			continue;
134		if (tag != OF_DT_PROP)
135			return NULL;
136
137		sz = be32_to_cpup((__be32 *)p);
138		noff = be32_to_cpup((__be32 *)(p + 4));
139		p += 8;
140		if (be32_to_cpu(initial_boot_params->version) < 0x10)
141			p = ALIGN(p, sz >= 8 ? 8 : 4);
142
143		nstr = find_flat_dt_string(noff);
144		if (nstr == NULL) {
145			pr_warning("Can't find property index name !\n");
146			return NULL;
147		}
148		if (strcmp(name, nstr) == 0) {
149			if (size)
150				*size = sz;
151			return (void *)p;
152		}
153		p += sz;
154		p = ALIGN(p, 4);
155	} while (1);
156}
157
158/**
159 * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
160 * @node: node to test
161 * @compat: compatible string to compare with compatible list.
162 */
163int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
164{
165	const char *cp;
166	unsigned long cplen, l;
167
168	cp = of_get_flat_dt_prop(node, "compatible", &cplen);
169	if (cp == NULL)
170		return 0;
171	while (cplen > 0) {
172		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
173			return 1;
174		l = strlen(cp) + 1;
175		cp += l;
176		cplen -= l;
177	}
178
179	return 0;
180}
181
182static void *__init unflatten_dt_alloc(unsigned long *mem, unsigned long size,
183				       unsigned long align)
184{
185	void *res;
186
187	*mem = ALIGN(*mem, align);
188	res = (void *)*mem;
189	*mem += size;
190
191	return res;
192}
193
194/**
195 * unflatten_dt_node - Alloc and populate a device_node from the flat tree
196 * @p: pointer to node in flat tree
197 * @dad: Parent struct device_node
198 * @allnextpp: pointer to ->allnext from last allocated device_node
199 * @fpsize: Size of the node path up at the current depth.
200 */
201unsigned long __init unflatten_dt_node(unsigned long mem,
202					unsigned long *p,
203					struct device_node *dad,
204					struct device_node ***allnextpp,
205					unsigned long fpsize)
206{
207	struct device_node *np;
208	struct property *pp, **prev_pp = NULL;
209	char *pathp;
210	u32 tag;
211	unsigned int l, allocl;
212	int has_name = 0;
213	int new_format = 0;
214
215	tag = be32_to_cpup((__be32 *)(*p));
216	if (tag != OF_DT_BEGIN_NODE) {
217		pr_err("Weird tag at start of node: %x\n", tag);
218		return mem;
219	}
220	*p += 4;
221	pathp = (char *)*p;
222	l = allocl = strlen(pathp) + 1;
223	*p = ALIGN(*p + l, 4);
224
225	/* version 0x10 has a more compact unit name here instead of the full
226	 * path. we accumulate the full path size using "fpsize", we'll rebuild
227	 * it later. We detect this because the first character of the name is
228	 * not '/'.
229	 */
230	if ((*pathp) != '/') {
231		new_format = 1;
232		if (fpsize == 0) {
233			/* root node: special case. fpsize accounts for path
234			 * plus terminating zero. root node only has '/', so
235			 * fpsize should be 2, but we want to avoid the first
236			 * level nodes to have two '/' so we use fpsize 1 here
237			 */
238			fpsize = 1;
239			allocl = 2;
240		} else {
241			/* account for '/' and path size minus terminal 0
242			 * already in 'l'
243			 */
244			fpsize += l;
245			allocl = fpsize;
246		}
247	}
248
249	np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl,
250				__alignof__(struct device_node));
251	if (allnextpp) {
252		memset(np, 0, sizeof(*np));
253		np->full_name = ((char *)np) + sizeof(struct device_node);
254		if (new_format) {
255			char *fn = np->full_name;
256			/* rebuild full path for new format */
257			if (dad && dad->parent) {
258				strcpy(fn, dad->full_name);
259#ifdef DEBUG
260				if ((strlen(fn) + l + 1) != allocl) {
261					pr_debug("%s: p: %d, l: %d, a: %d\n",
262						pathp, (int)strlen(fn),
263						l, allocl);
264				}
265#endif
266				fn += strlen(fn);
267			}
268			*(fn++) = '/';
269			memcpy(fn, pathp, l);
270		} else
271			memcpy(np->full_name, pathp, l);
272		prev_pp = &np->properties;
273		**allnextpp = np;
274		*allnextpp = &np->allnext;
275		if (dad != NULL) {
276			np->parent = dad;
277			/* we temporarily use the next field as `last_child'*/
278			if (dad->next == NULL)
279				dad->child = np;
280			else
281				dad->next->sibling = np;
282			dad->next = np;
283		}
284		kref_init(&np->kref);
285	}
286	while (1) {
287		u32 sz, noff;
288		char *pname;
289
290		tag = be32_to_cpup((__be32 *)(*p));
291		if (tag == OF_DT_NOP) {
292			*p += 4;
293			continue;
294		}
295		if (tag != OF_DT_PROP)
296			break;
297		*p += 4;
298		sz = be32_to_cpup((__be32 *)(*p));
299		noff = be32_to_cpup((__be32 *)((*p) + 4));
300		*p += 8;
301		if (be32_to_cpu(initial_boot_params->version) < 0x10)
302			*p = ALIGN(*p, sz >= 8 ? 8 : 4);
303
304		pname = find_flat_dt_string(noff);
305		if (pname == NULL) {
306			pr_info("Can't find property name in list !\n");
307			break;
308		}
309		if (strcmp(pname, "name") == 0)
310			has_name = 1;
311		l = strlen(pname) + 1;
312		pp = unflatten_dt_alloc(&mem, sizeof(struct property),
313					__alignof__(struct property));
314		if (allnextpp) {
315			/* We accept flattened tree phandles either in
316			 * ePAPR-style "phandle" properties, or the
317			 * legacy "linux,phandle" properties.  If both
318			 * appear and have different values, things
319			 * will get weird.  Don't do that. */
320			if ((strcmp(pname, "phandle") == 0) ||
321			    (strcmp(pname, "linux,phandle") == 0)) {
322				if (np->phandle == 0)
323					np->phandle = be32_to_cpup((__be32*)*p);
324			}
325			/* And we process the "ibm,phandle" property
326			 * used in pSeries dynamic device tree
327			 * stuff */
328			if (strcmp(pname, "ibm,phandle") == 0)
329				np->phandle = be32_to_cpup((__be32 *)*p);
330			pp->name = pname;
331			pp->length = sz;
332			pp->value = (void *)*p;
333			*prev_pp = pp;
334			prev_pp = &pp->next;
335		}
336		*p = ALIGN((*p) + sz, 4);
337	}
338	/* with version 0x10 we may not have the name property, recreate
339	 * it here from the unit name if absent
340	 */
341	if (!has_name) {
342		char *p1 = pathp, *ps = pathp, *pa = NULL;
343		int sz;
344
345		while (*p1) {
346			if ((*p1) == '@')
347				pa = p1;
348			if ((*p1) == '/')
349				ps = p1 + 1;
350			p1++;
351		}
352		if (pa < ps)
353			pa = p1;
354		sz = (pa - ps) + 1;
355		pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz,
356					__alignof__(struct property));
357		if (allnextpp) {
358			pp->name = "name";
359			pp->length = sz;
360			pp->value = pp + 1;
361			*prev_pp = pp;
362			prev_pp = &pp->next;
363			memcpy(pp->value, ps, sz - 1);
364			((char *)pp->value)[sz - 1] = 0;
365			pr_debug("fixed up name for %s -> %s\n", pathp,
366				(char *)pp->value);
367		}
368	}
369	if (allnextpp) {
370		*prev_pp = NULL;
371		np->name = of_get_property(np, "name", NULL);
372		np->type = of_get_property(np, "device_type", NULL);
373
374		if (!np->name)
375			np->name = "<NULL>";
376		if (!np->type)
377			np->type = "<NULL>";
378	}
379	while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
380		if (tag == OF_DT_NOP)
381			*p += 4;
382		else
383			mem = unflatten_dt_node(mem, p, np, allnextpp, fpsize);
384		tag = be32_to_cpup((__be32 *)(*p));
385	}
386	if (tag != OF_DT_END_NODE) {
387		pr_err("Weird tag at end of node: %x\n", tag);
388		return mem;
389	}
390	*p += 4;
391	return mem;
392}
393
394#ifdef CONFIG_BLK_DEV_INITRD
395/**
396 * early_init_dt_check_for_initrd - Decode initrd location from flat tree
397 * @node: reference to node containing initrd location ('chosen')
398 */
399void __init early_init_dt_check_for_initrd(unsigned long node)
400{
401	unsigned long start, end, len;
402	__be32 *prop;
403
404	pr_debug("Looking for initrd properties... ");
405
406	prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
407	if (!prop)
408		return;
409	start = of_read_ulong(prop, len/4);
410
411	prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
412	if (!prop)
413		return;
414	end = of_read_ulong(prop, len/4);
415
416	early_init_dt_setup_initrd_arch(start, end);
417	pr_debug("initrd_start=0x%lx  initrd_end=0x%lx\n", start, end);
418}
419#else
420inline void early_init_dt_check_for_initrd(unsigned long node)
421{
422}
423#endif /* CONFIG_BLK_DEV_INITRD */
424
425/**
426 * early_init_dt_scan_root - fetch the top level address and size cells
427 */
428int __init early_init_dt_scan_root(unsigned long node, const char *uname,
429				   int depth, void *data)
430{
431	__be32 *prop;
432
433	if (depth != 0)
434		return 0;
435
436	dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
437	dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
438
439	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
440	if (prop)
441		dt_root_size_cells = be32_to_cpup(prop);
442	pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
443
444	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
445	if (prop)
446		dt_root_addr_cells = be32_to_cpup(prop);
447	pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
448
449	/* break now */
450	return 1;
451}
452
453u64 __init dt_mem_next_cell(int s, __be32 **cellp)
454{
455	__be32 *p = *cellp;
456
457	*cellp = p + s;
458	return of_read_number(p, s);
459}
460
461/**
462 * early_init_dt_scan_memory - Look for an parse memory nodes
463 */
464int __init early_init_dt_scan_memory(unsigned long node, const char *uname,
465				     int depth, void *data)
466{
467	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
468	__be32 *reg, *endp;
469	unsigned long l;
470
471	/* We are scanning "memory" nodes only */
472	if (type == NULL) {
473		/*
474		 * The longtrail doesn't have a device_type on the
475		 * /memory node, so look for the node called /memory@0.
476		 */
477		if (depth != 1 || strcmp(uname, "memory@0") != 0)
478			return 0;
479	} else if (strcmp(type, "memory") != 0)
480		return 0;
481
482	reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
483	if (reg == NULL)
484		reg = of_get_flat_dt_prop(node, "reg", &l);
485	if (reg == NULL)
486		return 0;
487
488	endp = reg + (l / sizeof(__be32));
489
490	pr_debug("memory scan node %s, reg size %ld, data: %x %x %x %x,\n",
491	    uname, l, reg[0], reg[1], reg[2], reg[3]);
492
493	while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
494		u64 base, size;
495
496		base = dt_mem_next_cell(dt_root_addr_cells, &reg);
497		size = dt_mem_next_cell(dt_root_size_cells, &reg);
498
499		if (size == 0)
500			continue;
501		pr_debug(" - %llx ,  %llx\n", (unsigned long long)base,
502		    (unsigned long long)size);
503
504		early_init_dt_add_memory_arch(base, size);
505	}
506
507	return 0;
508}
509
510int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,
511				     int depth, void *data)
512{
513	unsigned long l;
514	char *p;
515
516	pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
517
518	if (depth != 1 ||
519	    (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
520		return 0;
521
522	early_init_dt_check_for_initrd(node);
523
524	/* Retreive command line */
525	p = of_get_flat_dt_prop(node, "bootargs", &l);
526	if (p != NULL && l > 0)
527		strlcpy(cmd_line, p, min((int)l, COMMAND_LINE_SIZE));
528
529#ifdef CONFIG_CMDLINE
530#ifndef CONFIG_CMDLINE_FORCE
531	if (p == NULL || l == 0 || (l == 1 && (*p) == 0))
532#endif
533		strlcpy(cmd_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
534#endif /* CONFIG_CMDLINE */
535
536	early_init_dt_scan_chosen_arch(node);
537
538	pr_debug("Command line is: %s\n", cmd_line);
539
540	/* break now */
541	return 1;
542}
543
544/**
545 * unflatten_device_tree - create tree of device_nodes from flat blob
546 *
547 * unflattens the device-tree passed by the firmware, creating the
548 * tree of struct device_node. It also fills the "name" and "type"
549 * pointers of the nodes so the normal device-tree walking functions
550 * can be used.
551 */
552void __init unflatten_device_tree(void)
553{
554	unsigned long start, mem, size;
555	struct device_node **allnextp = &allnodes;
556
557	pr_debug(" -> unflatten_device_tree()\n");
558
559	if (!initial_boot_params) {
560		pr_debug("No device tree pointer\n");
561		return;
562	}
563
564	pr_debug("Unflattening device tree:\n");
565	pr_debug("magic: %08x\n", be32_to_cpu(initial_boot_params->magic));
566	pr_debug("size: %08x\n", be32_to_cpu(initial_boot_params->totalsize));
567	pr_debug("version: %08x\n", be32_to_cpu(initial_boot_params->version));
568
569	if (be32_to_cpu(initial_boot_params->magic) != OF_DT_HEADER) {
570		pr_err("Invalid device tree blob header\n");
571		return;
572	}
573
574	/* First pass, scan for size */
575	start = ((unsigned long)initial_boot_params) +
576		be32_to_cpu(initial_boot_params->off_dt_struct);
577	size = unflatten_dt_node(0, &start, NULL, NULL, 0);
578	size = (size | 3) + 1;
579
580	pr_debug("  size is %lx, allocating...\n", size);
581
582	/* Allocate memory for the expanded device tree */
583	mem = early_init_dt_alloc_memory_arch(size + 4,
584			__alignof__(struct device_node));
585	mem = (unsigned long) __va(mem);
586
587	((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);
588
589	pr_debug("  unflattening %lx...\n", mem);
590
591	/* Second pass, do actual unflattening */
592	start = ((unsigned long)initial_boot_params) +
593		be32_to_cpu(initial_boot_params->off_dt_struct);
594	unflatten_dt_node(mem, &start, NULL, &allnextp, 0);
595	if (be32_to_cpup((__be32 *)start) != OF_DT_END)
596		pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start));
597	if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
598		pr_warning("End of tree marker overwritten: %08x\n",
599			   be32_to_cpu(((__be32 *)mem)[size / 4]));
600	*allnextp = NULL;
601
602	/* Get pointer to OF "/chosen" node for use everywhere */
603	of_chosen = of_find_node_by_path("/chosen");
604	if (of_chosen == NULL)
605		of_chosen = of_find_node_by_path("/chosen@0");
606
607	pr_debug(" <- unflatten_device_tree()\n");
608}
609