xref: /freebsd/sys/dev/ofw/openfirm.c (revision 609cdb12b9620dfa7c124b2f1834cd79e5cd98ec)
1 /*	$NetBSD: Locore.c,v 1.7 2000/08/20 07:04:59 tsubai Exp $	*/
2 
3 /*-
4  * SPDX-License-Identifier: BSD-4-Clause
5  *
6  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
7  * Copyright (C) 1995, 1996 TooLs GmbH.
8  * All rights reserved.
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  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by TooLs GmbH.
21  * 4. The name of TooLs GmbH may not be used to endorse or promote products
22  *    derived from this software without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
30  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
31  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
32  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
33  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  */
35 /*-
36  * Copyright (C) 2000 Benno Rice.
37  * All rights reserved.
38  *
39  * Redistribution and use in source and binary forms, with or without
40  * modification, are permitted provided that the following conditions
41  * are met:
42  * 1. Redistributions of source code must retain the above copyright
43  *    notice, this list of conditions and the following disclaimer.
44  * 2. Redistributions in binary form must reproduce the above copyright
45  *    notice, this list of conditions and the following disclaimer in the
46  *    documentation and/or other materials provided with the distribution.
47  *
48  * THIS SOFTWARE IS PROVIDED BY Benno Rice ``AS IS'' AND ANY EXPRESS OR
49  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
50  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
51  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
52  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
53  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
54  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
55  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
56  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
57  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
58  */
59 
60 #include <sys/cdefs.h>
61 #include "opt_platform.h"
62 
63 #include <sys/param.h>
64 #include <sys/kernel.h>
65 #include <sys/lock.h>
66 #include <sys/malloc.h>
67 #include <sys/mutex.h>
68 #include <sys/queue.h>
69 #include <sys/systm.h>
70 #include <sys/endian.h>
71 
72 #include <machine/stdarg.h>
73 
74 #include <dev/ofw/ofwvar.h>
75 #include <dev/ofw/openfirm.h>
76 
77 #include "ofw_if.h"
78 
79 static void OF_putchar(int c, void *arg);
80 
81 MALLOC_DEFINE(M_OFWPROP, "openfirm", "Open Firmware properties");
82 
83 static ihandle_t stdout;
84 
85 static ofw_def_t	*ofw_def_impl = NULL;
86 static ofw_t		ofw_obj;
87 static struct ofw_kobj	ofw_kernel_obj;
88 static struct kobj_ops	ofw_kernel_kops;
89 
90 struct xrefinfo {
91 	phandle_t	xref;
92 	phandle_t 	node;
93 	device_t  	dev;
94 	SLIST_ENTRY(xrefinfo) next_entry;
95 };
96 
97 static SLIST_HEAD(, xrefinfo) xreflist = SLIST_HEAD_INITIALIZER(xreflist);
98 static struct mtx xreflist_lock;
99 static bool xref_init_done;
100 
101 #define	FIND_BY_XREF	0
102 #define	FIND_BY_NODE	1
103 #define	FIND_BY_DEV	2
104 
105 /*
106  * xref-phandle-device lookup helper routines.
107  *
108  * As soon as we are able to use malloc(), walk the node tree and build a list
109  * of info that cross-references node handles, xref handles, and device_t
110  * instances.  This list exists primarily to allow association of a device_t
111  * with an xref handle, but it is also used to speed up translation between xref
112  * and node handles.  Before malloc() is available we have to recursively search
113  * the node tree each time we want to translate between a node and xref handle.
114  * Afterwards we can do the translations by searching this much shorter list.
115  */
116 static void
117 xrefinfo_create(phandle_t node)
118 {
119 	struct xrefinfo * xi;
120 	phandle_t child, xref;
121 
122 	/*
123 	 * Recursively descend from parent, looking for nodes with a property
124 	 * named either "phandle", "ibm,phandle", or "linux,phandle".  For each
125 	 * such node found create an entry in the xreflist.
126 	 */
127 	for (child = OF_child(node); child != 0; child = OF_peer(child)) {
128 		xrefinfo_create(child);
129 		if (OF_getencprop(child, "phandle", &xref, sizeof(xref)) ==
130 		    -1 && OF_getencprop(child, "ibm,phandle", &xref,
131 		    sizeof(xref)) == -1 && OF_getencprop(child,
132 		    "linux,phandle", &xref, sizeof(xref)) == -1)
133 			continue;
134 		xi = malloc(sizeof(*xi), M_OFWPROP, M_WAITOK | M_ZERO);
135 		xi->node = child;
136 		xi->xref = xref;
137 		SLIST_INSERT_HEAD(&xreflist, xi, next_entry);
138 	}
139 }
140 
141 static void
142 xrefinfo_init(void *unsed)
143 {
144 
145 	/*
146 	 * There is no locking during this init because it runs much earlier
147 	 * than any of the clients/consumers of the xref list data, but we do
148 	 * initialize the mutex that will be used for access later.
149 	 */
150 	mtx_init(&xreflist_lock, "OF xreflist lock", NULL, MTX_DEF);
151 	xrefinfo_create(OF_peer(0));
152 	xref_init_done = true;
153 }
154 SYSINIT(xrefinfo, SI_SUB_KMEM, SI_ORDER_ANY, xrefinfo_init, NULL);
155 
156 static struct xrefinfo *
157 xrefinfo_find(uintptr_t key, int find_by)
158 {
159 	struct xrefinfo *rv, *xi;
160 
161 	rv = NULL;
162 	mtx_lock(&xreflist_lock);
163 	SLIST_FOREACH(xi, &xreflist, next_entry) {
164 		if ((find_by == FIND_BY_XREF && (phandle_t)key == xi->xref) ||
165 		    (find_by == FIND_BY_NODE && (phandle_t)key == xi->node) ||
166 		    (find_by == FIND_BY_DEV && key == (uintptr_t)xi->dev)) {
167 			rv = xi;
168 			break;
169 		}
170 	}
171 	mtx_unlock(&xreflist_lock);
172 	return (rv);
173 }
174 
175 static struct xrefinfo *
176 xrefinfo_add(phandle_t node, phandle_t xref, device_t dev)
177 {
178 	struct xrefinfo *xi;
179 
180 	xi = malloc(sizeof(*xi), M_OFWPROP, M_WAITOK);
181 	xi->node = node;
182 	xi->xref = xref;
183 	xi->dev  = dev;
184 	mtx_lock(&xreflist_lock);
185 	SLIST_INSERT_HEAD(&xreflist, xi, next_entry);
186 	mtx_unlock(&xreflist_lock);
187 	return (xi);
188 }
189 
190 /*
191  * OFW install routines.  Highest priority wins, equal priority also
192  * overrides allowing last-set to win.
193  */
194 SET_DECLARE(ofw_set, ofw_def_t);
195 
196 bool
197 OF_install(char *name, int prio)
198 {
199 	ofw_def_t *ofwp, **ofwpp;
200 	static int curr_prio = 0;
201 
202 	/* Allow OF layer to be uninstalled */
203 	if (name == NULL) {
204 		ofw_def_impl = NULL;
205 		return (false);
206 	}
207 
208 	/*
209 	 * Try and locate the OFW kobj corresponding to the name.
210 	 */
211 	SET_FOREACH(ofwpp, ofw_set) {
212 		ofwp = *ofwpp;
213 
214 		if (ofwp->name &&
215 		    !strcmp(ofwp->name, name) &&
216 		    prio >= curr_prio) {
217 			curr_prio = prio;
218 			ofw_def_impl = ofwp;
219 			return (true);
220 		}
221 	}
222 
223 	return (false);
224 }
225 
226 /* Initializer */
227 int
228 OF_init(void *cookie)
229 {
230 	phandle_t chosen;
231 	int rv;
232 
233 	if (ofw_def_impl == NULL)
234 		return (-1);
235 
236 	ofw_obj = &ofw_kernel_obj;
237 	/*
238 	 * Take care of compiling the selected class, and
239 	 * then statically initialize the OFW object.
240 	 */
241 	kobj_class_compile_static(ofw_def_impl, &ofw_kernel_kops);
242 	kobj_init_static((kobj_t)ofw_obj, ofw_def_impl);
243 
244 	rv = OFW_INIT(ofw_obj, cookie);
245 
246 	if ((chosen = OF_finddevice("/chosen")) != -1)
247 		if (OF_getencprop(chosen, "stdout", &stdout,
248 		    sizeof(stdout)) == -1)
249 			stdout = -1;
250 
251 	return (rv);
252 }
253 
254 static void
255 OF_putchar(int c, void *arg __unused)
256 {
257 	char cbuf;
258 
259 	if (c == '\n') {
260 		cbuf = '\r';
261 		OF_write(stdout, &cbuf, 1);
262 	}
263 
264 	cbuf = c;
265 	OF_write(stdout, &cbuf, 1);
266 }
267 
268 void
269 OF_printf(const char *fmt, ...)
270 {
271 	va_list	va;
272 
273 	va_start(va, fmt);
274 	(void)kvprintf(fmt, OF_putchar, NULL, 10, va);
275 	va_end(va);
276 }
277 
278 /*
279  * Generic functions
280  */
281 
282 /* Test to see if a service exists. */
283 int
284 OF_test(const char *name)
285 {
286 
287 	if (ofw_def_impl == NULL)
288 		return (-1);
289 
290 	return (OFW_TEST(ofw_obj, name));
291 }
292 
293 int
294 OF_interpret(const char *cmd, int nreturns, ...)
295 {
296 	va_list ap;
297 	cell_t slots[16];
298 	int i = 0;
299 	int status;
300 
301 	if (ofw_def_impl == NULL)
302 		return (-1);
303 
304 	status = OFW_INTERPRET(ofw_obj, cmd, nreturns, slots);
305 	if (status == -1)
306 		return (status);
307 
308 	va_start(ap, nreturns);
309 	while (i < nreturns)
310 		*va_arg(ap, cell_t *) = slots[i++];
311 	va_end(ap);
312 
313 	return (status);
314 }
315 
316 /*
317  * Device tree functions
318  */
319 
320 /* Return the next sibling of this node or 0. */
321 phandle_t
322 OF_peer(phandle_t node)
323 {
324 
325 	if (ofw_def_impl == NULL)
326 		return (0);
327 
328 	return (OFW_PEER(ofw_obj, node));
329 }
330 
331 /* Return the first child of this node or 0. */
332 phandle_t
333 OF_child(phandle_t node)
334 {
335 
336 	if (ofw_def_impl == NULL)
337 		return (0);
338 
339 	return (OFW_CHILD(ofw_obj, node));
340 }
341 
342 /* Return the parent of this node or 0. */
343 phandle_t
344 OF_parent(phandle_t node)
345 {
346 
347 	if (ofw_def_impl == NULL)
348 		return (0);
349 
350 	return (OFW_PARENT(ofw_obj, node));
351 }
352 
353 /* Return the package handle that corresponds to an instance handle. */
354 phandle_t
355 OF_instance_to_package(ihandle_t instance)
356 {
357 
358 	if (ofw_def_impl == NULL)
359 		return (-1);
360 
361 	return (OFW_INSTANCE_TO_PACKAGE(ofw_obj, instance));
362 }
363 
364 /* Get the length of a property of a package. */
365 ssize_t
366 OF_getproplen(phandle_t package, const char *propname)
367 {
368 
369 	if (ofw_def_impl == NULL)
370 		return (-1);
371 
372 	return (OFW_GETPROPLEN(ofw_obj, package, propname));
373 }
374 
375 /* Check existence of a property of a package. */
376 int
377 OF_hasprop(phandle_t package, const char *propname)
378 {
379 
380 	return (OF_getproplen(package, propname) >= 0 ? 1 : 0);
381 }
382 
383 /* Get the value of a property of a package. */
384 ssize_t
385 OF_getprop(phandle_t package, const char *propname, void *buf, size_t buflen)
386 {
387 
388 	if (ofw_def_impl == NULL)
389 		return (-1);
390 
391 	return (OFW_GETPROP(ofw_obj, package, propname, buf, buflen));
392 }
393 
394 ssize_t
395 OF_getencprop(phandle_t node, const char *propname, pcell_t *buf, size_t len)
396 {
397 	ssize_t retval;
398 	int i;
399 
400 	KASSERT(len % 4 == 0, ("Need a multiple of 4 bytes"));
401 
402 	retval = OF_getprop(node, propname, buf, len);
403 	if (retval <= 0)
404 		return (retval);
405 
406 	for (i = 0; i < len/4; i++)
407 		buf[i] = be32toh(buf[i]);
408 
409 	return (retval);
410 }
411 
412 /*
413  * Recursively search the node and its parent for the given property, working
414  * downward from the node to the device tree root.  Returns the value of the
415  * first match.
416  */
417 ssize_t
418 OF_searchprop(phandle_t node, const char *propname, void *buf, size_t len)
419 {
420 	ssize_t rv;
421 
422 	for (; node != 0; node = OF_parent(node))
423 		if ((rv = OF_getprop(node, propname, buf, len)) != -1)
424 			return (rv);
425 	return (-1);
426 }
427 
428 ssize_t
429 OF_searchencprop(phandle_t node, const char *propname, pcell_t *buf, size_t len)
430 {
431 	ssize_t rv;
432 
433 	for (; node != 0; node = OF_parent(node))
434 		if ((rv = OF_getencprop(node, propname, buf, len)) != -1)
435 			return (rv);
436 	return (-1);
437 }
438 
439 /*
440  * Store the value of a property of a package into newly allocated memory
441  * (using the M_OFWPROP malloc pool and M_WAITOK).
442  */
443 ssize_t
444 OF_getprop_alloc(phandle_t package, const char *propname, void **buf)
445 {
446 	int len;
447 
448 	*buf = NULL;
449 	if ((len = OF_getproplen(package, propname)) == -1)
450 		return (-1);
451 
452 	if (len > 0) {
453 		*buf = malloc(len, M_OFWPROP, M_WAITOK);
454 		if (OF_getprop(package, propname, *buf, len) == -1) {
455 			free(*buf, M_OFWPROP);
456 			*buf = NULL;
457 			return (-1);
458 		}
459 	}
460 	return (len);
461 }
462 
463 /*
464  * Store the value of a property of a package into newly allocated memory
465  * (using the M_OFWPROP malloc pool and M_WAITOK).  elsz is the size of a
466  * single element, the number of elements is return in number.
467  */
468 ssize_t
469 OF_getprop_alloc_multi(phandle_t package, const char *propname, int elsz, void **buf)
470 {
471 	int len;
472 
473 	*buf = NULL;
474 	if ((len = OF_getproplen(package, propname)) == -1 ||
475 	    len % elsz != 0)
476 		return (-1);
477 
478 	if (len > 0) {
479 		*buf = malloc(len, M_OFWPROP, M_WAITOK);
480 		if (OF_getprop(package, propname, *buf, len) == -1) {
481 			free(*buf, M_OFWPROP);
482 			*buf = NULL;
483 			return (-1);
484 		}
485 	}
486 	return (len / elsz);
487 }
488 
489 ssize_t
490 OF_getencprop_alloc(phandle_t package, const char *name, void **buf)
491 {
492 	ssize_t ret;
493 
494 	ret = OF_getencprop_alloc_multi(package, name, sizeof(pcell_t),
495 	    buf);
496 	if (ret < 0)
497 		return (ret);
498 	else
499 		return (ret * sizeof(pcell_t));
500 }
501 
502 ssize_t
503 OF_getencprop_alloc_multi(phandle_t package, const char *name, int elsz,
504     void **buf)
505 {
506 	ssize_t retval;
507 	pcell_t *cell;
508 	int i;
509 
510 	retval = OF_getprop_alloc_multi(package, name, elsz, buf);
511 	if (retval == -1)
512 		return (-1);
513 
514 	cell = *buf;
515 	for (i = 0; i < retval * elsz / 4; i++)
516 		cell[i] = be32toh(cell[i]);
517 
518 	return (retval);
519 }
520 
521 /* Free buffer allocated by OF_getencprop_alloc or OF_getprop_alloc */
522 void OF_prop_free(void *buf)
523 {
524 
525 	free(buf, M_OFWPROP);
526 }
527 
528 /* Get the next property of a package. */
529 int
530 OF_nextprop(phandle_t package, const char *previous, char *buf, size_t size)
531 {
532 
533 	if (ofw_def_impl == NULL)
534 		return (-1);
535 
536 	return (OFW_NEXTPROP(ofw_obj, package, previous, buf, size));
537 }
538 
539 /* Set the value of a property of a package. */
540 int
541 OF_setprop(phandle_t package, const char *propname, const void *buf, size_t len)
542 {
543 
544 	if (ofw_def_impl == NULL)
545 		return (-1);
546 
547 	return (OFW_SETPROP(ofw_obj, package, propname, buf,len));
548 }
549 
550 /* Convert a device specifier to a fully qualified pathname. */
551 ssize_t
552 OF_canon(const char *device, char *buf, size_t len)
553 {
554 
555 	if (ofw_def_impl == NULL)
556 		return (-1);
557 
558 	return (OFW_CANON(ofw_obj, device, buf, len));
559 }
560 
561 /* Return a package handle for the specified device. */
562 phandle_t
563 OF_finddevice(const char *device)
564 {
565 
566 	if (ofw_def_impl == NULL)
567 		return (-1);
568 
569 	return (OFW_FINDDEVICE(ofw_obj, device));
570 }
571 
572 /* Return the fully qualified pathname corresponding to an instance. */
573 ssize_t
574 OF_instance_to_path(ihandle_t instance, char *buf, size_t len)
575 {
576 
577 	if (ofw_def_impl == NULL)
578 		return (-1);
579 
580 	return (OFW_INSTANCE_TO_PATH(ofw_obj, instance, buf, len));
581 }
582 
583 /* Return the fully qualified pathname corresponding to a package. */
584 ssize_t
585 OF_package_to_path(phandle_t package, char *buf, size_t len)
586 {
587 
588 	if (ofw_def_impl == NULL)
589 		return (-1);
590 
591 	return (OFW_PACKAGE_TO_PATH(ofw_obj, package, buf, len));
592 }
593 
594 /* Look up effective phandle (see FDT/PAPR spec) */
595 static phandle_t
596 OF_child_xref_phandle(phandle_t parent, phandle_t xref)
597 {
598 	phandle_t child, rxref;
599 
600 	/*
601 	 * Recursively descend from parent, looking for a node with a property
602 	 * named either "phandle", "ibm,phandle", or "linux,phandle" that
603 	 * matches the xref we are looking for.
604 	 */
605 
606 	for (child = OF_child(parent); child != 0; child = OF_peer(child)) {
607 		rxref = OF_child_xref_phandle(child, xref);
608 		if (rxref != -1)
609 			return (rxref);
610 
611 		if (OF_getencprop(child, "phandle", &rxref, sizeof(rxref)) ==
612 		    -1 && OF_getencprop(child, "ibm,phandle", &rxref,
613 		    sizeof(rxref)) == -1 && OF_getencprop(child,
614 		    "linux,phandle", &rxref, sizeof(rxref)) == -1)
615 			continue;
616 
617 		if (rxref == xref)
618 			return (child);
619 	}
620 
621 	return (-1);
622 }
623 
624 phandle_t
625 OF_node_from_xref(phandle_t xref)
626 {
627 	struct xrefinfo *xi;
628 	phandle_t node;
629 
630 	if (xref_init_done) {
631 		if ((xi = xrefinfo_find(xref, FIND_BY_XREF)) == NULL)
632 			return (xref);
633 		return (xi->node);
634 	}
635 
636 	if ((node = OF_child_xref_phandle(OF_peer(0), xref)) == -1)
637 		return (xref);
638 	return (node);
639 }
640 
641 phandle_t
642 OF_xref_from_node(phandle_t node)
643 {
644 	struct xrefinfo *xi;
645 	phandle_t xref;
646 
647 	if (xref_init_done) {
648 		if ((xi = xrefinfo_find(node, FIND_BY_NODE)) == NULL)
649 			return (node);
650 		return (xi->xref);
651 	}
652 
653 	if (OF_getencprop(node, "phandle", &xref, sizeof(xref)) == -1 &&
654 	    OF_getencprop(node, "ibm,phandle", &xref, sizeof(xref)) == -1 &&
655 	    OF_getencprop(node, "linux,phandle", &xref, sizeof(xref)) == -1)
656 		return (node);
657 	return (xref);
658 }
659 
660 device_t
661 OF_device_from_xref(phandle_t xref)
662 {
663 	struct xrefinfo *xi;
664 
665 	if (xref_init_done) {
666 		if ((xi = xrefinfo_find(xref, FIND_BY_XREF)) == NULL)
667 			return (NULL);
668 		return (xi->dev);
669 	}
670 	panic("Attempt to find device before xreflist_init");
671 }
672 
673 phandle_t
674 OF_xref_from_device(device_t dev)
675 {
676 	struct xrefinfo *xi;
677 
678 	if (xref_init_done) {
679 		if ((xi = xrefinfo_find((uintptr_t)dev, FIND_BY_DEV)) == NULL)
680 			return (0);
681 		return (xi->xref);
682 	}
683 	panic("Attempt to find xref before xreflist_init");
684 }
685 
686 int
687 OF_device_register_xref(phandle_t xref, device_t dev)
688 {
689 	struct xrefinfo *xi;
690 
691 	/*
692 	 * If the given xref handle doesn't already exist in the list then we
693 	 * add a list entry.  In theory this can only happen on a system where
694 	 * nodes don't contain phandle properties and xref and node handles are
695 	 * synonymous, so the xref handle is added as the node handle as well.
696 	 */
697 	if (xref_init_done) {
698 		if ((xi = xrefinfo_find(xref, FIND_BY_XREF)) == NULL)
699 			xrefinfo_add(xref, xref, dev);
700 		else
701 			xi->dev = dev;
702 		return (0);
703 	}
704 	panic("Attempt to register device before xreflist_init");
705 }
706 
707 /*  Call the method in the scope of a given instance. */
708 int
709 OF_call_method(const char *method, ihandle_t instance, int nargs, int nreturns,
710     ...)
711 {
712 	va_list ap;
713 	cell_t args_n_results[12];
714 	int n, status;
715 
716 	if (nargs > 6 || ofw_def_impl == NULL)
717 		return (-1);
718 	va_start(ap, nreturns);
719 	for (n = 0; n < nargs; n++)
720 		args_n_results[n] = va_arg(ap, cell_t);
721 
722 	status = OFW_CALL_METHOD(ofw_obj, instance, method, nargs, nreturns,
723 	    args_n_results);
724 	if (status != 0)
725 		return (status);
726 
727 	for (; n < nargs + nreturns; n++)
728 		*va_arg(ap, cell_t *) = args_n_results[n];
729 	va_end(ap);
730 	return (0);
731 }
732 
733 /*
734  * Device I/O functions
735  */
736 
737 /* Open an instance for a device. */
738 ihandle_t
739 OF_open(const char *device)
740 {
741 
742 	if (ofw_def_impl == NULL)
743 		return (0);
744 
745 	return (OFW_OPEN(ofw_obj, device));
746 }
747 
748 /* Close an instance. */
749 void
750 OF_close(ihandle_t instance)
751 {
752 
753 	if (ofw_def_impl == NULL)
754 		return;
755 
756 	OFW_CLOSE(ofw_obj, instance);
757 }
758 
759 /* Read from an instance. */
760 ssize_t
761 OF_read(ihandle_t instance, void *addr, size_t len)
762 {
763 
764 	if (ofw_def_impl == NULL)
765 		return (-1);
766 
767 	return (OFW_READ(ofw_obj, instance, addr, len));
768 }
769 
770 /* Write to an instance. */
771 ssize_t
772 OF_write(ihandle_t instance, const void *addr, size_t len)
773 {
774 
775 	if (ofw_def_impl == NULL)
776 		return (-1);
777 
778 	return (OFW_WRITE(ofw_obj, instance, addr, len));
779 }
780 
781 /* Seek to a position. */
782 int
783 OF_seek(ihandle_t instance, uint64_t pos)
784 {
785 
786 	if (ofw_def_impl == NULL)
787 		return (-1);
788 
789 	return (OFW_SEEK(ofw_obj, instance, pos));
790 }
791 
792 /*
793  * Memory functions
794  */
795 
796 /* Claim an area of memory. */
797 void *
798 OF_claim(void *virt, size_t size, u_int align)
799 {
800 
801 	if (ofw_def_impl == NULL)
802 		return ((void *)-1);
803 
804 	return (OFW_CLAIM(ofw_obj, virt, size, align));
805 }
806 
807 /* Release an area of memory. */
808 void
809 OF_release(void *virt, size_t size)
810 {
811 
812 	if (ofw_def_impl == NULL)
813 		return;
814 
815 	OFW_RELEASE(ofw_obj, virt, size);
816 }
817 
818 /*
819  * Control transfer functions
820  */
821 
822 /* Suspend and drop back to the Open Firmware interface. */
823 void
824 OF_enter(void)
825 {
826 
827 	if (ofw_def_impl == NULL)
828 		return;
829 
830 	OFW_ENTER(ofw_obj);
831 }
832 
833 /* Shut down and drop back to the Open Firmware interface. */
834 void
835 OF_exit(void)
836 {
837 
838 	if (ofw_def_impl == NULL)
839 		panic("OF_exit: Open Firmware not available");
840 
841 	/* Should not return */
842 	OFW_EXIT(ofw_obj);
843 
844 	for (;;)			/* just in case */
845 		;
846 }
847