xref: /freebsd/sys/dev/fdt/fdt_common.c (revision 98e0ffaefb0f241cda3a72395d3be04192ae0d47)
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 
42 #include <machine/resource.h>
43 
44 #include <dev/fdt/fdt_common.h>
45 #include <dev/ofw/ofw_bus.h>
46 #include <dev/ofw/ofw_bus_subr.h>
47 #include <dev/ofw/openfirm.h>
48 
49 #include "ofw_bus_if.h"
50 
51 #ifdef DEBUG
52 #define debugf(fmt, args...) do { printf("%s(): ", __func__);	\
53     printf(fmt,##args); } while (0)
54 #else
55 #define debugf(fmt, args...)
56 #endif
57 
58 #define FDT_COMPAT_LEN	255
59 #define FDT_TYPE_LEN	64
60 #define FDT_NAME_LEN	32
61 
62 #define FDT_REG_CELLS	4
63 
64 vm_paddr_t fdt_immr_pa;
65 vm_offset_t fdt_immr_va;
66 vm_offset_t fdt_immr_size;
67 
68 struct fdt_ic_list fdt_ic_list_head = SLIST_HEAD_INITIALIZER(fdt_ic_list_head);
69 
70 static int
71 fdt_get_range_by_busaddr(phandle_t node, u_long addr, u_long *base,
72     u_long *size)
73 {
74 	pcell_t ranges[32], *rangesptr;
75 	pcell_t addr_cells, size_cells, par_addr_cells;
76 	u_long bus_addr, par_bus_addr, pbase, psize;
77 	int err, i, len, tuple_size, tuples;
78 
79 	if (node == 0) {
80 		*base = 0;
81 		*size = ULONG_MAX;
82 		return (0);
83 	}
84 
85 	if ((fdt_addrsize_cells(node, &addr_cells, &size_cells)) != 0)
86 		return (ENXIO);
87 	/*
88 	 * Process 'ranges' property.
89 	 */
90 	par_addr_cells = fdt_parent_addr_cells(node);
91 	if (par_addr_cells > 2) {
92 		return (ERANGE);
93 	}
94 
95 	len = OF_getproplen(node, "ranges");
96 	if (len < 0)
97 		return (-1);
98 	if (len > sizeof(ranges))
99 		return (ENOMEM);
100 	if (len == 0) {
101 		return (fdt_get_range_by_busaddr(OF_parent(node), addr,
102 		    base, size));
103 	}
104 
105 	if (OF_getprop(node, "ranges", ranges, sizeof(ranges)) <= 0)
106 		return (EINVAL);
107 
108 	tuple_size = addr_cells + par_addr_cells + size_cells;
109 	tuples = len / (tuple_size * sizeof(cell_t));
110 
111 	if (par_addr_cells > 2 || addr_cells > 2 || size_cells > 2)
112 		return (ERANGE);
113 
114 	*base = 0;
115 	*size = 0;
116 
117 	for (i = 0; i < tuples; i++) {
118 		rangesptr = &ranges[i * tuple_size];
119 
120 		bus_addr = fdt_data_get((void *)rangesptr, addr_cells);
121 		if (bus_addr != addr)
122 			continue;
123 		rangesptr += addr_cells;
124 
125 		par_bus_addr = fdt_data_get((void *)rangesptr, par_addr_cells);
126 		rangesptr += par_addr_cells;
127 
128 		err = fdt_get_range_by_busaddr(OF_parent(node), par_bus_addr,
129 		    &pbase, &psize);
130 		if (err > 0)
131 			return (err);
132 		if (err == 0)
133 			*base = pbase;
134 		else
135 			*base = par_bus_addr;
136 
137 		*size = fdt_data_get((void *)rangesptr, size_cells);
138 
139 		return (0);
140 	}
141 
142 	return (EINVAL);
143 }
144 
145 int
146 fdt_get_range(phandle_t node, int range_id, u_long *base, u_long *size)
147 {
148 	pcell_t ranges[6], *rangesptr;
149 	pcell_t addr_cells, size_cells, par_addr_cells;
150 	u_long par_bus_addr, pbase, psize;
151 	int err, len, tuple_size, tuples;
152 
153 	if ((fdt_addrsize_cells(node, &addr_cells, &size_cells)) != 0)
154 		return (ENXIO);
155 	/*
156 	 * Process 'ranges' property.
157 	 */
158 	par_addr_cells = fdt_parent_addr_cells(node);
159 	if (par_addr_cells > 2)
160 		return (ERANGE);
161 
162 	len = OF_getproplen(node, "ranges");
163 	if (len > sizeof(ranges))
164 		return (ENOMEM);
165 	if (len == 0) {
166 		*base = 0;
167 		*size = ULONG_MAX;
168 		return (0);
169 	}
170 
171 	if (!(range_id < len))
172 		return (ERANGE);
173 
174 	if (OF_getprop(node, "ranges", ranges, sizeof(ranges)) <= 0)
175 		return (EINVAL);
176 
177 	tuple_size = sizeof(pcell_t) * (addr_cells + par_addr_cells +
178 	    size_cells);
179 	tuples = len / tuple_size;
180 
181 	if (par_addr_cells > 2 || addr_cells > 2 || size_cells > 2)
182 		return (ERANGE);
183 
184 	*base = 0;
185 	*size = 0;
186 	rangesptr = &ranges[range_id];
187 
188 	*base = fdt_data_get((void *)rangesptr, addr_cells);
189 	rangesptr += addr_cells;
190 
191 	par_bus_addr = fdt_data_get((void *)rangesptr, par_addr_cells);
192 	rangesptr += par_addr_cells;
193 
194 	err = fdt_get_range_by_busaddr(OF_parent(node), par_bus_addr,
195 	   &pbase, &psize);
196 	if (err == 0)
197 		*base += pbase;
198 	else
199 		*base += par_bus_addr;
200 
201 	*size = fdt_data_get((void *)rangesptr, size_cells);
202 	return (0);
203 }
204 
205 int
206 fdt_immr_addr(vm_offset_t immr_va)
207 {
208 	phandle_t node;
209 	u_long base, size;
210 	int r;
211 
212 	/*
213 	 * Try to access the SOC node directly i.e. through /aliases/.
214 	 */
215 	if ((node = OF_finddevice("soc")) != 0)
216 		if (fdt_is_compatible_strict(node, "simple-bus"))
217 			goto moveon;
218 	/*
219 	 * Find the node the long way.
220 	 */
221 	if ((node = OF_finddevice("/")) == 0)
222 		return (ENXIO);
223 
224 	if ((node = fdt_find_compatible(node, "simple-bus", 1)) == 0)
225 		return (ENXIO);
226 
227 moveon:
228 	if ((r = fdt_get_range(node, 0, &base, &size)) == 0) {
229 		fdt_immr_pa = base;
230 		fdt_immr_va = immr_va;
231 		fdt_immr_size = size;
232 	}
233 
234 	return (r);
235 }
236 
237 /*
238  * This routine is an early-usage version of the ofw_bus_is_compatible() when
239  * the ofw_bus I/F is not available (like early console routines and similar).
240  * Note the buffer has to be on the stack since malloc() is usually not
241  * available in such cases either.
242  */
243 int
244 fdt_is_compatible(phandle_t node, const char *compatstr)
245 {
246 	char buf[FDT_COMPAT_LEN];
247 	char *compat;
248 	int len, onelen, l, rv;
249 
250 	if ((len = OF_getproplen(node, "compatible")) <= 0)
251 		return (0);
252 
253 	compat = (char *)&buf;
254 	bzero(compat, FDT_COMPAT_LEN);
255 
256 	if (OF_getprop(node, "compatible", compat, FDT_COMPAT_LEN) < 0)
257 		return (0);
258 
259 	onelen = strlen(compatstr);
260 	rv = 0;
261 	while (len > 0) {
262 		if (strncasecmp(compat, compatstr, onelen) == 0) {
263 			/* Found it. */
264 			rv = 1;
265 			break;
266 		}
267 		/* Slide to the next sub-string. */
268 		l = strlen(compat) + 1;
269 		compat += l;
270 		len -= l;
271 	}
272 
273 	return (rv);
274 }
275 
276 int
277 fdt_is_compatible_strict(phandle_t node, const char *compatible)
278 {
279 	char compat[FDT_COMPAT_LEN];
280 
281 	if (OF_getproplen(node, "compatible") <= 0)
282 		return (0);
283 
284 	if (OF_getprop(node, "compatible", compat, FDT_COMPAT_LEN) < 0)
285 		return (0);
286 
287 	if (strncasecmp(compat, compatible, FDT_COMPAT_LEN) == 0)
288 		/* This fits. */
289 		return (1);
290 
291 	return (0);
292 }
293 
294 phandle_t
295 fdt_find_compatible(phandle_t start, const char *compat, int strict)
296 {
297 	phandle_t child;
298 
299 	/*
300 	 * Traverse all children of 'start' node, and find first with
301 	 * matching 'compatible' property.
302 	 */
303 	for (child = OF_child(start); child != 0; child = OF_peer(child))
304 		if (fdt_is_compatible(child, compat)) {
305 			if (strict)
306 				if (!fdt_is_compatible_strict(child, compat))
307 					continue;
308 			return (child);
309 		}
310 	return (0);
311 }
312 
313 phandle_t
314 fdt_find_child(phandle_t start, const char *child_name)
315 {
316 	char name[FDT_NAME_LEN];
317 	phandle_t child;
318 
319 	for (child = OF_child(start); child != 0; child = OF_peer(child)) {
320 		if (OF_getprop(child, "name", name, sizeof(name)) <= 0)
321 			continue;
322 		if (strcmp(name, child_name) == 0)
323 			return (child);
324 	}
325 
326 	return (0);
327 }
328 
329 phandle_t
330 fdt_depth_search_compatible(phandle_t start, const char *compat, int strict)
331 {
332 	phandle_t child, node;
333 
334 	/*
335 	 * Depth-search all descendants of 'start' node, and find first with
336 	 * matching 'compatible' property.
337 	 */
338 	for (node = OF_child(start); node != 0; node = OF_peer(node)) {
339 		if (fdt_is_compatible(node, compat) &&
340 		    (strict == 0 || fdt_is_compatible_strict(node, compat))) {
341 			return (node);
342 		}
343 		child = fdt_depth_search_compatible(node, compat, strict);
344 		if (child != 0)
345 			return (child);
346 	}
347 	return (0);
348 }
349 
350 int
351 fdt_is_enabled(phandle_t node)
352 {
353 	char *stat;
354 	int ena, len;
355 
356 	len = OF_getprop_alloc(node, "status", sizeof(char),
357 	    (void **)&stat);
358 
359 	if (len <= 0)
360 		/* It is OK if no 'status' property. */
361 		return (1);
362 
363 	/* Anything other than 'okay' means disabled. */
364 	ena = 0;
365 	if (strncmp((char *)stat, "okay", len) == 0)
366 		ena = 1;
367 
368 	free(stat, M_OFWPROP);
369 	return (ena);
370 }
371 
372 int
373 fdt_is_type(phandle_t node, const char *typestr)
374 {
375 	char type[FDT_TYPE_LEN];
376 
377 	if (OF_getproplen(node, "device_type") <= 0)
378 		return (0);
379 
380 	if (OF_getprop(node, "device_type", type, FDT_TYPE_LEN) < 0)
381 		return (0);
382 
383 	if (strncasecmp(type, typestr, FDT_TYPE_LEN) == 0)
384 		/* This fits. */
385 		return (1);
386 
387 	return (0);
388 }
389 
390 int
391 fdt_parent_addr_cells(phandle_t node)
392 {
393 	pcell_t addr_cells;
394 
395 	/* Find out #address-cells of the superior bus. */
396 	if (OF_searchprop(OF_parent(node), "#address-cells", &addr_cells,
397 	    sizeof(addr_cells)) <= 0)
398 		return (2);
399 
400 	return ((int)fdt32_to_cpu(addr_cells));
401 }
402 
403 int
404 fdt_pm_is_enabled(phandle_t node)
405 {
406 	int ret;
407 
408 	ret = 1;
409 
410 #if defined(SOC_MV_KIRKWOOD) || defined(SOC_MV_DISCOVERY)
411 	ret = fdt_pm(node);
412 #endif
413 	return (ret);
414 }
415 
416 u_long
417 fdt_data_get(void *data, int cells)
418 {
419 
420 	if (cells == 1)
421 		return (fdt32_to_cpu(*((uint32_t *)data)));
422 
423 	return (fdt64_to_cpu(*((uint64_t *)data)));
424 }
425 
426 int
427 fdt_addrsize_cells(phandle_t node, int *addr_cells, int *size_cells)
428 {
429 	pcell_t cell;
430 	int cell_size;
431 
432 	/*
433 	 * Retrieve #{address,size}-cells.
434 	 */
435 	cell_size = sizeof(cell);
436 	if (OF_getprop(node, "#address-cells", &cell, cell_size) < cell_size)
437 		cell = 2;
438 	*addr_cells = fdt32_to_cpu((int)cell);
439 
440 	if (OF_getprop(node, "#size-cells", &cell, cell_size) < cell_size)
441 		cell = 1;
442 	*size_cells = fdt32_to_cpu((int)cell);
443 
444 	if (*addr_cells > 3 || *size_cells > 2)
445 		return (ERANGE);
446 	return (0);
447 }
448 
449 int
450 fdt_data_to_res(pcell_t *data, int addr_cells, int size_cells, u_long *start,
451     u_long *count)
452 {
453 
454 	/* Address portion. */
455 	if (addr_cells > 2)
456 		return (ERANGE);
457 
458 	*start = fdt_data_get((void *)data, addr_cells);
459 	data += addr_cells;
460 
461 	/* Size portion. */
462 	if (size_cells > 2)
463 		return (ERANGE);
464 
465 	*count = fdt_data_get((void *)data, size_cells);
466 	return (0);
467 }
468 
469 int
470 fdt_regsize(phandle_t node, u_long *base, u_long *size)
471 {
472 	pcell_t reg[4];
473 	int addr_cells, len, size_cells;
474 
475 	if (fdt_addrsize_cells(OF_parent(node), &addr_cells, &size_cells))
476 		return (ENXIO);
477 
478 	if ((sizeof(pcell_t) * (addr_cells + size_cells)) > sizeof(reg))
479 		return (ENOMEM);
480 
481 	len = OF_getprop(node, "reg", &reg, sizeof(reg));
482 	if (len <= 0)
483 		return (EINVAL);
484 
485 	*base = fdt_data_get(&reg[0], addr_cells);
486 	*size = fdt_data_get(&reg[addr_cells], size_cells);
487 	return (0);
488 }
489 
490 int
491 fdt_reg_to_rl(phandle_t node, struct resource_list *rl)
492 {
493 	u_long end, count, start;
494 	pcell_t *reg, *regptr;
495 	pcell_t addr_cells, size_cells;
496 	int tuple_size, tuples;
497 	int i, rv;
498 	long busaddr, bussize;
499 
500 	if (fdt_addrsize_cells(OF_parent(node), &addr_cells, &size_cells) != 0)
501 		return (ENXIO);
502 	if (fdt_get_range(OF_parent(node), 0, &busaddr, &bussize)) {
503 		busaddr = 0;
504 		bussize = 0;
505 	}
506 
507 	tuple_size = sizeof(pcell_t) * (addr_cells + size_cells);
508 	tuples = OF_getprop_alloc(node, "reg", tuple_size, (void **)&reg);
509 	debugf("addr_cells = %d, size_cells = %d\n", addr_cells, size_cells);
510 	debugf("tuples = %d, tuple size = %d\n", tuples, tuple_size);
511 	if (tuples <= 0)
512 		/* No 'reg' property in this node. */
513 		return (0);
514 
515 	regptr = reg;
516 	for (i = 0; i < tuples; i++) {
517 
518 		rv = fdt_data_to_res(reg, addr_cells, size_cells, &start,
519 		    &count);
520 		if (rv != 0) {
521 			resource_list_free(rl);
522 			goto out;
523 		}
524 		reg += addr_cells + size_cells;
525 
526 		/* Calculate address range relative to base. */
527 		start += busaddr;
528 		end = start + count - 1;
529 
530 		debugf("reg addr start = %lx, end = %lx, count = %lx\n", start,
531 		    end, count);
532 
533 		resource_list_add(rl, SYS_RES_MEMORY, i, start, end,
534 		    count);
535 	}
536 	rv = 0;
537 
538 out:
539 	free(regptr, M_OFWPROP);
540 	return (rv);
541 }
542 
543 int
544 fdt_get_phyaddr(phandle_t node, device_t dev, int *phy_addr, void **phy_sc)
545 {
546 	phandle_t phy_node;
547 	pcell_t phy_handle, phy_reg;
548 	uint32_t i;
549 	device_t parent, child;
550 
551 	if (OF_getencprop(node, "phy-handle", (void *)&phy_handle,
552 	    sizeof(phy_handle)) <= 0)
553 		return (ENXIO);
554 
555 	phy_node = OF_node_from_xref(phy_handle);
556 
557 	if (OF_getprop(phy_node, "reg", (void *)&phy_reg,
558 	    sizeof(phy_reg)) <= 0)
559 		return (ENXIO);
560 
561 	*phy_addr = fdt32_to_cpu(phy_reg);
562 
563 	/*
564 	 * Search for softc used to communicate with phy.
565 	 */
566 
567 	/*
568 	 * Step 1: Search for ancestor of the phy-node with a "phy-handle"
569 	 * property set.
570 	 */
571 	phy_node = OF_parent(phy_node);
572 	while (phy_node != 0) {
573 		if (OF_getprop(phy_node, "phy-handle", (void *)&phy_handle,
574 		    sizeof(phy_handle)) > 0)
575 			break;
576 		phy_node = OF_parent(phy_node);
577 	}
578 	if (phy_node == 0)
579 		return (ENXIO);
580 
581 	/*
582 	 * Step 2: For each device with the same parent and name as ours
583 	 * compare its node with the one found in step 1, ancestor of phy
584 	 * node (stored in phy_node).
585 	 */
586 	parent = device_get_parent(dev);
587 	i = 0;
588 	child = device_find_child(parent, device_get_name(dev), i);
589 	while (child != NULL) {
590 		if (ofw_bus_get_node(child) == phy_node)
591 			break;
592 		i++;
593 		child = device_find_child(parent, device_get_name(dev), i);
594 	}
595 	if (child == NULL)
596 		return (ENXIO);
597 
598 	/*
599 	 * Use softc of the device found.
600 	 */
601 	*phy_sc = (void *)device_get_softc(child);
602 
603 	return (0);
604 }
605 
606 int
607 fdt_get_reserved_regions(struct mem_region *mr, int *mrcnt)
608 {
609 	pcell_t reserve[FDT_REG_CELLS * FDT_MEM_REGIONS];
610 	pcell_t *reservep;
611 	phandle_t memory, root;
612 	uint32_t memory_size;
613 	int addr_cells, size_cells;
614 	int i, max_size, res_len, rv, tuple_size, tuples;
615 
616 	max_size = sizeof(reserve);
617 	root = OF_finddevice("/");
618 	memory = OF_finddevice("/memory");
619 	if (memory == -1) {
620 		rv = ENXIO;
621 		goto out;
622 	}
623 
624 	if ((rv = fdt_addrsize_cells(OF_parent(memory), &addr_cells,
625 	    &size_cells)) != 0)
626 		goto out;
627 
628 	if (addr_cells > 2) {
629 		rv = ERANGE;
630 		goto out;
631 	}
632 
633 	tuple_size = sizeof(pcell_t) * (addr_cells + size_cells);
634 
635 	res_len = OF_getproplen(root, "memreserve");
636 	if (res_len <= 0 || res_len > sizeof(reserve)) {
637 		rv = ERANGE;
638 		goto out;
639 	}
640 
641 	if (OF_getprop(root, "memreserve", reserve, res_len) <= 0) {
642 		rv = ENXIO;
643 		goto out;
644 	}
645 
646 	memory_size = 0;
647 	tuples = res_len / tuple_size;
648 	reservep = (pcell_t *)&reserve;
649 	for (i = 0; i < tuples; i++) {
650 
651 		rv = fdt_data_to_res(reservep, addr_cells, size_cells,
652 			(u_long *)&mr[i].mr_start, (u_long *)&mr[i].mr_size);
653 
654 		if (rv != 0)
655 			goto out;
656 
657 		reservep += addr_cells + size_cells;
658 	}
659 
660 	*mrcnt = i;
661 	rv = 0;
662 out:
663 	return (rv);
664 }
665 
666 int
667 fdt_get_mem_regions(struct mem_region *mr, int *mrcnt, uint32_t *memsize)
668 {
669 	pcell_t reg[FDT_REG_CELLS * FDT_MEM_REGIONS];
670 	pcell_t *regp;
671 	phandle_t memory;
672 	uint32_t memory_size;
673 	int addr_cells, size_cells;
674 	int i, max_size, reg_len, rv, tuple_size, tuples;
675 
676 	max_size = sizeof(reg);
677 	memory = OF_finddevice("/memory");
678 	if (memory == -1) {
679 		rv = ENXIO;
680 		goto out;
681 	}
682 
683 	if ((rv = fdt_addrsize_cells(OF_parent(memory), &addr_cells,
684 	    &size_cells)) != 0)
685 		goto out;
686 
687 	if (addr_cells > 2) {
688 		rv = ERANGE;
689 		goto out;
690 	}
691 
692 	tuple_size = sizeof(pcell_t) * (addr_cells + size_cells);
693 	reg_len = OF_getproplen(memory, "reg");
694 	if (reg_len <= 0 || reg_len > sizeof(reg)) {
695 		rv = ERANGE;
696 		goto out;
697 	}
698 
699 	if (OF_getprop(memory, "reg", reg, reg_len) <= 0) {
700 		rv = ENXIO;
701 		goto out;
702 	}
703 
704 	memory_size = 0;
705 	tuples = reg_len / tuple_size;
706 	regp = (pcell_t *)&reg;
707 	for (i = 0; i < tuples; i++) {
708 
709 		rv = fdt_data_to_res(regp, addr_cells, size_cells,
710 			(u_long *)&mr[i].mr_start, (u_long *)&mr[i].mr_size);
711 
712 		if (rv != 0)
713 			goto out;
714 
715 		regp += addr_cells + size_cells;
716 		memory_size += mr[i].mr_size;
717 	}
718 
719 	if (memory_size == 0) {
720 		rv = ERANGE;
721 		goto out;
722 	}
723 
724 	*mrcnt = i;
725 	*memsize = memory_size;
726 	rv = 0;
727 out:
728 	return (rv);
729 }
730 
731 int
732 fdt_get_unit(device_t dev)
733 {
734 	const char * name;
735 
736 	name = ofw_bus_get_name(dev);
737 	name = strchr(name, '@') + 1;
738 
739 	return (strtol(name,NULL,0));
740 }
741