xref: /freebsd/sys/dev/fdt/fdt_common.c (revision 40427cca7a9ae77b095936fb1954417c290cfb17)
1 /*-
2  * Copyright (c) 2009-2014 The FreeBSD Foundation
3  * All rights reserved.
4  *
5  * This software was developed by Andrew Turner under sponsorship from
6  * the FreeBSD Foundation.
7  * This software was developed by Semihalf under sponsorship from
8  * the FreeBSD Foundation.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/module.h>
39 #include <sys/bus.h>
40 #include <sys/limits.h>
41 #include <sys/sysctl.h>
42 
43 #include <machine/resource.h>
44 
45 #include <dev/fdt/fdt_common.h>
46 #include <dev/ofw/ofw_bus.h>
47 #include <dev/ofw/ofw_bus_subr.h>
48 #include <dev/ofw/openfirm.h>
49 
50 #include "ofw_bus_if.h"
51 
52 #ifdef DEBUG
53 #define debugf(fmt, args...) do { printf("%s(): ", __func__);	\
54     printf(fmt,##args); } while (0)
55 #else
56 #define debugf(fmt, args...)
57 #endif
58 
59 #define FDT_COMPAT_LEN	255
60 #define FDT_TYPE_LEN	64
61 
62 #define FDT_REG_CELLS	4
63 #define FDT_RANGES_SIZE 48
64 
65 SYSCTL_NODE(_hw, OID_AUTO, fdt, CTLFLAG_RD, 0, "Flattened Device Tree");
66 
67 vm_paddr_t fdt_immr_pa;
68 vm_offset_t fdt_immr_va;
69 vm_offset_t fdt_immr_size;
70 
71 struct fdt_ic_list fdt_ic_list_head = SLIST_HEAD_INITIALIZER(fdt_ic_list_head);
72 
73 static int fdt_is_compatible(phandle_t, const char *);
74 
75 static int
76 fdt_get_range_by_busaddr(phandle_t node, u_long addr, u_long *base,
77     u_long *size)
78 {
79 	pcell_t ranges[32], *rangesptr;
80 	pcell_t addr_cells, size_cells, par_addr_cells;
81 	u_long bus_addr, par_bus_addr, pbase, psize;
82 	int err, i, len, tuple_size, tuples;
83 
84 	if (node == 0) {
85 		*base = 0;
86 		*size = ULONG_MAX;
87 		return (0);
88 	}
89 
90 	if ((fdt_addrsize_cells(node, &addr_cells, &size_cells)) != 0)
91 		return (ENXIO);
92 	/*
93 	 * Process 'ranges' property.
94 	 */
95 	par_addr_cells = fdt_parent_addr_cells(node);
96 	if (par_addr_cells > 2) {
97 		return (ERANGE);
98 	}
99 
100 	len = OF_getproplen(node, "ranges");
101 	if (len < 0)
102 		return (-1);
103 	if (len > sizeof(ranges))
104 		return (ENOMEM);
105 	if (len == 0) {
106 		return (fdt_get_range_by_busaddr(OF_parent(node), addr,
107 		    base, size));
108 	}
109 
110 	if (OF_getprop(node, "ranges", ranges, sizeof(ranges)) <= 0)
111 		return (EINVAL);
112 
113 	tuple_size = addr_cells + par_addr_cells + size_cells;
114 	tuples = len / (tuple_size * sizeof(cell_t));
115 
116 	if (par_addr_cells > 2 || addr_cells > 2 || size_cells > 2)
117 		return (ERANGE);
118 
119 	*base = 0;
120 	*size = 0;
121 
122 	for (i = 0; i < tuples; i++) {
123 		rangesptr = &ranges[i * tuple_size];
124 
125 		bus_addr = fdt_data_get((void *)rangesptr, addr_cells);
126 		if (bus_addr != addr)
127 			continue;
128 		rangesptr += addr_cells;
129 
130 		par_bus_addr = fdt_data_get((void *)rangesptr, par_addr_cells);
131 		rangesptr += par_addr_cells;
132 
133 		err = fdt_get_range_by_busaddr(OF_parent(node), par_bus_addr,
134 		    &pbase, &psize);
135 		if (err > 0)
136 			return (err);
137 		if (err == 0)
138 			*base = pbase;
139 		else
140 			*base = par_bus_addr;
141 
142 		*size = fdt_data_get((void *)rangesptr, size_cells);
143 
144 		return (0);
145 	}
146 
147 	return (EINVAL);
148 }
149 
150 int
151 fdt_get_range(phandle_t node, int range_id, u_long *base, u_long *size)
152 {
153 	pcell_t ranges[FDT_RANGES_SIZE], *rangesptr;
154 	pcell_t addr_cells, size_cells, par_addr_cells;
155 	u_long par_bus_addr, pbase, psize;
156 	int err, len, tuple_size, tuples;
157 
158 	if ((fdt_addrsize_cells(node, &addr_cells, &size_cells)) != 0)
159 		return (ENXIO);
160 	/*
161 	 * Process 'ranges' property.
162 	 */
163 	par_addr_cells = fdt_parent_addr_cells(node);
164 	if (par_addr_cells > 2)
165 		return (ERANGE);
166 
167 	len = OF_getproplen(node, "ranges");
168 	if (len > sizeof(ranges))
169 		return (ENOMEM);
170 	if (len == 0) {
171 		*base = 0;
172 		*size = ULONG_MAX;
173 		return (0);
174 	}
175 
176 	if (!(range_id < len))
177 		return (ERANGE);
178 
179 	if (OF_getprop(node, "ranges", ranges, sizeof(ranges)) <= 0)
180 		return (EINVAL);
181 
182 	tuple_size = sizeof(pcell_t) * (addr_cells + par_addr_cells +
183 	    size_cells);
184 	tuples = len / tuple_size;
185 
186 	if (par_addr_cells > 2 || addr_cells > 2 || size_cells > 2)
187 		return (ERANGE);
188 
189 	*base = 0;
190 	*size = 0;
191 	rangesptr = &ranges[range_id];
192 
193 	*base = fdt_data_get((void *)rangesptr, addr_cells);
194 	rangesptr += addr_cells;
195 
196 	par_bus_addr = fdt_data_get((void *)rangesptr, par_addr_cells);
197 	rangesptr += par_addr_cells;
198 
199 	err = fdt_get_range_by_busaddr(OF_parent(node), par_bus_addr,
200 	   &pbase, &psize);
201 	if (err == 0)
202 		*base += pbase;
203 	else
204 		*base += par_bus_addr;
205 
206 	*size = fdt_data_get((void *)rangesptr, size_cells);
207 	return (0);
208 }
209 
210 int
211 fdt_immr_addr(vm_offset_t immr_va)
212 {
213 	phandle_t node;
214 	u_long base, size;
215 	int r;
216 
217 	/*
218 	 * Try to access the SOC node directly i.e. through /aliases/.
219 	 */
220 	if ((node = OF_finddevice("soc")) != 0)
221 		if (fdt_is_compatible(node, "simple-bus"))
222 			goto moveon;
223 	/*
224 	 * Find the node the long way.
225 	 */
226 	if ((node = OF_finddevice("/")) == 0)
227 		return (ENXIO);
228 
229 	if ((node = fdt_find_compatible(node, "simple-bus", 0)) == 0)
230 		return (ENXIO);
231 
232 moveon:
233 	if ((r = fdt_get_range(node, 0, &base, &size)) == 0) {
234 		fdt_immr_pa = base;
235 		fdt_immr_va = immr_va;
236 		fdt_immr_size = size;
237 	}
238 
239 	return (r);
240 }
241 
242 /*
243  * This routine is an early-usage version of the ofw_bus_is_compatible() when
244  * the ofw_bus I/F is not available (like early console routines and similar).
245  * Note the buffer has to be on the stack since malloc() is usually not
246  * available in such cases either.
247  */
248 static int
249 fdt_is_compatible(phandle_t node, const char *compatstr)
250 {
251 	char buf[FDT_COMPAT_LEN];
252 	char *compat;
253 	int len, onelen, l, rv;
254 
255 	if ((len = OF_getproplen(node, "compatible")) <= 0)
256 		return (0);
257 
258 	compat = (char *)&buf;
259 	bzero(compat, FDT_COMPAT_LEN);
260 
261 	if (OF_getprop(node, "compatible", compat, FDT_COMPAT_LEN) < 0)
262 		return (0);
263 
264 	onelen = strlen(compatstr);
265 	rv = 0;
266 	while (len > 0) {
267 		if (strncasecmp(compat, compatstr, onelen) == 0) {
268 			/* Found it. */
269 			rv = 1;
270 			break;
271 		}
272 		/* Slide to the next sub-string. */
273 		l = strlen(compat) + 1;
274 		compat += l;
275 		len -= l;
276 	}
277 
278 	return (rv);
279 }
280 
281 int
282 fdt_is_compatible_strict(phandle_t node, const char *compatible)
283 {
284 	char compat[FDT_COMPAT_LEN];
285 
286 	if (OF_getproplen(node, "compatible") <= 0)
287 		return (0);
288 
289 	if (OF_getprop(node, "compatible", compat, FDT_COMPAT_LEN) < 0)
290 		return (0);
291 
292 	if (strncasecmp(compat, compatible, FDT_COMPAT_LEN) == 0)
293 		/* This fits. */
294 		return (1);
295 
296 	return (0);
297 }
298 
299 phandle_t
300 fdt_find_compatible(phandle_t start, const char *compat, int strict)
301 {
302 	phandle_t child;
303 
304 	/*
305 	 * Traverse all children of 'start' node, and find first with
306 	 * matching 'compatible' property.
307 	 */
308 	for (child = OF_child(start); child != 0; child = OF_peer(child))
309 		if (fdt_is_compatible(child, compat)) {
310 			if (strict)
311 				if (!fdt_is_compatible_strict(child, compat))
312 					continue;
313 			return (child);
314 		}
315 	return (0);
316 }
317 
318 phandle_t
319 fdt_depth_search_compatible(phandle_t start, const char *compat, int strict)
320 {
321 	phandle_t child, node;
322 
323 	/*
324 	 * Depth-search all descendants of 'start' node, and find first with
325 	 * matching 'compatible' property.
326 	 */
327 	for (node = OF_child(start); node != 0; node = OF_peer(node)) {
328 		if (fdt_is_compatible(node, compat) &&
329 		    (strict == 0 || fdt_is_compatible_strict(node, compat))) {
330 			return (node);
331 		}
332 		child = fdt_depth_search_compatible(node, compat, strict);
333 		if (child != 0)
334 			return (child);
335 	}
336 	return (0);
337 }
338 
339 int
340 fdt_is_enabled(phandle_t node)
341 {
342 	char *stat;
343 	int ena, len;
344 
345 	len = OF_getprop_alloc(node, "status", sizeof(char),
346 	    (void **)&stat);
347 
348 	if (len <= 0)
349 		/* It is OK if no 'status' property. */
350 		return (1);
351 
352 	/* Anything other than 'okay' means disabled. */
353 	ena = 0;
354 	if (strncmp((char *)stat, "okay", len) == 0)
355 		ena = 1;
356 
357 	OF_prop_free(stat);
358 	return (ena);
359 }
360 
361 int
362 fdt_is_type(phandle_t node, const char *typestr)
363 {
364 	char type[FDT_TYPE_LEN];
365 
366 	if (OF_getproplen(node, "device_type") <= 0)
367 		return (0);
368 
369 	if (OF_getprop(node, "device_type", type, FDT_TYPE_LEN) < 0)
370 		return (0);
371 
372 	if (strncasecmp(type, typestr, FDT_TYPE_LEN) == 0)
373 		/* This fits. */
374 		return (1);
375 
376 	return (0);
377 }
378 
379 int
380 fdt_parent_addr_cells(phandle_t node)
381 {
382 	pcell_t addr_cells;
383 
384 	/* Find out #address-cells of the superior bus. */
385 	if (OF_searchprop(OF_parent(node), "#address-cells", &addr_cells,
386 	    sizeof(addr_cells)) <= 0)
387 		return (2);
388 
389 	return ((int)fdt32_to_cpu(addr_cells));
390 }
391 
392 int
393 fdt_pm_is_enabled(phandle_t node)
394 {
395 	int ret;
396 
397 	ret = 1;
398 
399 #if defined(SOC_MV_KIRKWOOD) || defined(SOC_MV_DISCOVERY)
400 	ret = fdt_pm(node);
401 #endif
402 	return (ret);
403 }
404 
405 u_long
406 fdt_data_get(void *data, int cells)
407 {
408 
409 	if (cells == 1)
410 		return (fdt32_to_cpu(*((uint32_t *)data)));
411 
412 	return (fdt64_to_cpu(*((uint64_t *)data)));
413 }
414 
415 int
416 fdt_addrsize_cells(phandle_t node, int *addr_cells, int *size_cells)
417 {
418 	pcell_t cell;
419 	int cell_size;
420 
421 	/*
422 	 * Retrieve #{address,size}-cells.
423 	 */
424 	cell_size = sizeof(cell);
425 	if (OF_getencprop(node, "#address-cells", &cell, cell_size) < cell_size)
426 		cell = 2;
427 	*addr_cells = (int)cell;
428 
429 	if (OF_getencprop(node, "#size-cells", &cell, cell_size) < cell_size)
430 		cell = 1;
431 	*size_cells = (int)cell;
432 
433 	if (*addr_cells > 3 || *size_cells > 2)
434 		return (ERANGE);
435 	return (0);
436 }
437 
438 int
439 fdt_data_to_res(pcell_t *data, int addr_cells, int size_cells, u_long *start,
440     u_long *count)
441 {
442 
443 	/* Address portion. */
444 	if (addr_cells > 2)
445 		return (ERANGE);
446 
447 	*start = fdt_data_get((void *)data, addr_cells);
448 	data += addr_cells;
449 
450 	/* Size portion. */
451 	if (size_cells > 2)
452 		return (ERANGE);
453 
454 	*count = fdt_data_get((void *)data, size_cells);
455 	return (0);
456 }
457 
458 int
459 fdt_regsize(phandle_t node, u_long *base, u_long *size)
460 {
461 	pcell_t reg[4];
462 	int addr_cells, len, size_cells;
463 
464 	if (fdt_addrsize_cells(OF_parent(node), &addr_cells, &size_cells))
465 		return (ENXIO);
466 
467 	if ((sizeof(pcell_t) * (addr_cells + size_cells)) > sizeof(reg))
468 		return (ENOMEM);
469 
470 	len = OF_getprop(node, "reg", &reg, sizeof(reg));
471 	if (len <= 0)
472 		return (EINVAL);
473 
474 	*base = fdt_data_get(&reg[0], addr_cells);
475 	*size = fdt_data_get(&reg[addr_cells], size_cells);
476 	return (0);
477 }
478 
479 int
480 fdt_reg_to_rl(phandle_t node, struct resource_list *rl)
481 {
482 	u_long end, count, start;
483 	pcell_t *reg, *regptr;
484 	pcell_t addr_cells, size_cells;
485 	int tuple_size, tuples;
486 	int i, rv;
487 	long busaddr, bussize;
488 
489 	if (fdt_addrsize_cells(OF_parent(node), &addr_cells, &size_cells) != 0)
490 		return (ENXIO);
491 	if (fdt_get_range(OF_parent(node), 0, &busaddr, &bussize)) {
492 		busaddr = 0;
493 		bussize = 0;
494 	}
495 
496 	tuple_size = sizeof(pcell_t) * (addr_cells + size_cells);
497 	tuples = OF_getprop_alloc(node, "reg", tuple_size, (void **)&reg);
498 	debugf("addr_cells = %d, size_cells = %d\n", addr_cells, size_cells);
499 	debugf("tuples = %d, tuple size = %d\n", tuples, tuple_size);
500 	if (tuples <= 0)
501 		/* No 'reg' property in this node. */
502 		return (0);
503 
504 	regptr = reg;
505 	for (i = 0; i < tuples; i++) {
506 
507 		rv = fdt_data_to_res(reg, addr_cells, size_cells, &start,
508 		    &count);
509 		if (rv != 0) {
510 			resource_list_free(rl);
511 			goto out;
512 		}
513 		reg += addr_cells + size_cells;
514 
515 		/* Calculate address range relative to base. */
516 		start += busaddr;
517 		end = start + count - 1;
518 
519 		debugf("reg addr start = %lx, end = %lx, count = %lx\n", start,
520 		    end, count);
521 
522 		resource_list_add(rl, SYS_RES_MEMORY, i, start, end,
523 		    count);
524 	}
525 	rv = 0;
526 
527 out:
528 	OF_prop_free(regptr);
529 	return (rv);
530 }
531 
532 int
533 fdt_get_phyaddr(phandle_t node, device_t dev, int *phy_addr, void **phy_sc)
534 {
535 	phandle_t phy_node;
536 	pcell_t phy_handle, phy_reg;
537 	uint32_t i;
538 	device_t parent, child;
539 
540 	if (OF_getencprop(node, "phy-handle", (void *)&phy_handle,
541 	    sizeof(phy_handle)) <= 0)
542 		return (ENXIO);
543 
544 	phy_node = OF_node_from_xref(phy_handle);
545 
546 	if (OF_getencprop(phy_node, "reg", (void *)&phy_reg,
547 	    sizeof(phy_reg)) <= 0)
548 		return (ENXIO);
549 
550 	*phy_addr = phy_reg;
551 
552 	/*
553 	 * Search for softc used to communicate with phy.
554 	 */
555 
556 	/*
557 	 * Step 1: Search for ancestor of the phy-node with a "phy-handle"
558 	 * property set.
559 	 */
560 	phy_node = OF_parent(phy_node);
561 	while (phy_node != 0) {
562 		if (OF_getprop(phy_node, "phy-handle", (void *)&phy_handle,
563 		    sizeof(phy_handle)) > 0)
564 			break;
565 		phy_node = OF_parent(phy_node);
566 	}
567 	if (phy_node == 0)
568 		return (ENXIO);
569 
570 	/*
571 	 * Step 2: For each device with the same parent and name as ours
572 	 * compare its node with the one found in step 1, ancestor of phy
573 	 * node (stored in phy_node).
574 	 */
575 	parent = device_get_parent(dev);
576 	i = 0;
577 	child = device_find_child(parent, device_get_name(dev), i);
578 	while (child != NULL) {
579 		if (ofw_bus_get_node(child) == phy_node)
580 			break;
581 		i++;
582 		child = device_find_child(parent, device_get_name(dev), i);
583 	}
584 	if (child == NULL)
585 		return (ENXIO);
586 
587 	/*
588 	 * Use softc of the device found.
589 	 */
590 	*phy_sc = (void *)device_get_softc(child);
591 
592 	return (0);
593 }
594 
595 int
596 fdt_get_reserved_regions(struct mem_region *mr, int *mrcnt)
597 {
598 	pcell_t reserve[FDT_REG_CELLS * FDT_MEM_REGIONS];
599 	pcell_t *reservep;
600 	phandle_t memory, root;
601 	uint32_t memory_size;
602 	int addr_cells, size_cells;
603 	int i, max_size, res_len, rv, tuple_size, tuples;
604 
605 	max_size = sizeof(reserve);
606 	root = OF_finddevice("/");
607 	memory = OF_finddevice("/memory");
608 	if (memory == -1) {
609 		rv = ENXIO;
610 		goto out;
611 	}
612 
613 	if ((rv = fdt_addrsize_cells(OF_parent(memory), &addr_cells,
614 	    &size_cells)) != 0)
615 		goto out;
616 
617 	if (addr_cells > 2) {
618 		rv = ERANGE;
619 		goto out;
620 	}
621 
622 	tuple_size = sizeof(pcell_t) * (addr_cells + size_cells);
623 
624 	res_len = OF_getproplen(root, "memreserve");
625 	if (res_len <= 0 || res_len > sizeof(reserve)) {
626 		rv = ERANGE;
627 		goto out;
628 	}
629 
630 	if (OF_getprop(root, "memreserve", reserve, res_len) <= 0) {
631 		rv = ENXIO;
632 		goto out;
633 	}
634 
635 	memory_size = 0;
636 	tuples = res_len / tuple_size;
637 	reservep = (pcell_t *)&reserve;
638 	for (i = 0; i < tuples; i++) {
639 
640 		rv = fdt_data_to_res(reservep, addr_cells, size_cells,
641 			(u_long *)&mr[i].mr_start, (u_long *)&mr[i].mr_size);
642 
643 		if (rv != 0)
644 			goto out;
645 
646 		reservep += addr_cells + size_cells;
647 	}
648 
649 	*mrcnt = i;
650 	rv = 0;
651 out:
652 	return (rv);
653 }
654 
655 int
656 fdt_get_mem_regions(struct mem_region *mr, int *mrcnt, uint64_t *memsize)
657 {
658 	pcell_t reg[FDT_REG_CELLS * FDT_MEM_REGIONS];
659 	pcell_t *regp;
660 	phandle_t memory;
661 	uint64_t memory_size;
662 	int addr_cells, size_cells;
663 	int i, max_size, reg_len, rv, tuple_size, tuples;
664 
665 	max_size = sizeof(reg);
666 	memory = OF_finddevice("/memory");
667 	if (memory == -1) {
668 		rv = ENXIO;
669 		goto out;
670 	}
671 
672 	if ((rv = fdt_addrsize_cells(OF_parent(memory), &addr_cells,
673 	    &size_cells)) != 0)
674 		goto out;
675 
676 	if (addr_cells > 2) {
677 		rv = ERANGE;
678 		goto out;
679 	}
680 
681 	tuple_size = sizeof(pcell_t) * (addr_cells + size_cells);
682 	reg_len = OF_getproplen(memory, "reg");
683 	if (reg_len <= 0 || reg_len > sizeof(reg)) {
684 		rv = ERANGE;
685 		goto out;
686 	}
687 
688 	if (OF_getprop(memory, "reg", reg, reg_len) <= 0) {
689 		rv = ENXIO;
690 		goto out;
691 	}
692 
693 	memory_size = 0;
694 	tuples = reg_len / tuple_size;
695 	regp = (pcell_t *)&reg;
696 	for (i = 0; i < tuples; i++) {
697 
698 		rv = fdt_data_to_res(regp, addr_cells, size_cells,
699 			(u_long *)&mr[i].mr_start, (u_long *)&mr[i].mr_size);
700 
701 		if (rv != 0)
702 			goto out;
703 
704 		regp += addr_cells + size_cells;
705 		memory_size += mr[i].mr_size;
706 	}
707 
708 	if (memory_size == 0) {
709 		rv = ERANGE;
710 		goto out;
711 	}
712 
713 	*mrcnt = i;
714 	if (memsize != NULL)
715 		*memsize = memory_size;
716 	rv = 0;
717 out:
718 	return (rv);
719 }
720 
721 int
722 fdt_get_unit(device_t dev)
723 {
724 	const char * name;
725 
726 	name = ofw_bus_get_name(dev);
727 	name = strchr(name, '@') + 1;
728 
729 	return (strtol(name,NULL,0));
730 }
731 
732 int
733 fdt_get_chosen_bootargs(char *bootargs, size_t max_size)
734 {
735 	phandle_t chosen;
736 
737 	chosen = OF_finddevice("/chosen");
738 	if (chosen == -1)
739 		return (ENXIO);
740 	if (OF_getprop(chosen, "bootargs", bootargs, max_size) == -1)
741 		return (ENXIO);
742 	return (0);
743 }
744