xref: /freebsd/sys/dev/ofw/openfirm.c (revision 952364486a4b9d135e4b28f7f88a8703a74eae6f)
1 /*	$NetBSD: Locore.c,v 1.7 2000/08/20 07:04:59 tsubai Exp $	*/
2 
3 /*-
4  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
5  * Copyright (C) 1995, 1996 TooLs GmbH.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by TooLs GmbH.
19  * 4. The name of TooLs GmbH may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
27  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
28  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
31  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 /*-
34  * Copyright (C) 2000 Benno Rice.
35  * All rights reserved.
36  *
37  * Redistribution and use in source and binary forms, with or without
38  * modification, are permitted provided that the following conditions
39  * are met:
40  * 1. Redistributions of source code must retain the above copyright
41  *    notice, this list of conditions and the following disclaimer.
42  * 2. Redistributions in binary form must reproduce the above copyright
43  *    notice, this list of conditions and the following disclaimer in the
44  *    documentation and/or other materials provided with the distribution.
45  *
46  * THIS SOFTWARE IS PROVIDED BY Benno Rice ``AS IS'' AND ANY EXPRESS OR
47  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
48  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
49  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
50  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
51  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
52  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
53  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
54  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
55  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
56  */
57 
58 #include <sys/cdefs.h>
59 __FBSDID("$FreeBSD$");
60 
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 boolean_t 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 boolean_t
197 OF_install(char *name, int prio)
198 {
199 	ofw_def_t *ofwp, **ofwpp;
200 	static int curr_prio = 0;
201 
202 	/*
203 	 * Try and locate the OFW kobj corresponding to the name.
204 	 */
205 	SET_FOREACH(ofwpp, ofw_set) {
206 		ofwp = *ofwpp;
207 
208 		if (ofwp->name &&
209 		    !strcmp(ofwp->name, name) &&
210 		    prio >= curr_prio) {
211 			curr_prio = prio;
212 			ofw_def_impl = ofwp;
213 			return (TRUE);
214 		}
215 	}
216 
217 	return (FALSE);
218 }
219 
220 /* Initializer */
221 int
222 OF_init(void *cookie)
223 {
224 	phandle_t chosen;
225 	int rv;
226 
227 	if (ofw_def_impl == NULL)
228 		return (-1);
229 
230 	ofw_obj = &ofw_kernel_obj;
231 	/*
232 	 * Take care of compiling the selected class, and
233 	 * then statically initialize the OFW object.
234 	 */
235 	kobj_class_compile_static(ofw_def_impl, &ofw_kernel_kops);
236 	kobj_init_static((kobj_t)ofw_obj, ofw_def_impl);
237 
238 	rv = OFW_INIT(ofw_obj, cookie);
239 
240 	if ((chosen = OF_finddevice("/chosen")) != -1)
241 		if (OF_getencprop(chosen, "stdout", &stdout,
242 		    sizeof(stdout)) == -1)
243 			stdout = -1;
244 
245 	return (rv);
246 }
247 
248 static void
249 OF_putchar(int c, void *arg __unused)
250 {
251 	char cbuf;
252 
253 	if (c == '\n') {
254 		cbuf = '\r';
255 		OF_write(stdout, &cbuf, 1);
256 	}
257 
258 	cbuf = c;
259 	OF_write(stdout, &cbuf, 1);
260 }
261 
262 void
263 OF_printf(const char *fmt, ...)
264 {
265 	va_list	va;
266 
267 	va_start(va, fmt);
268 	(void)kvprintf(fmt, OF_putchar, NULL, 10, va);
269 	va_end(va);
270 }
271 
272 /*
273  * Generic functions
274  */
275 
276 /* Test to see if a service exists. */
277 int
278 OF_test(const char *name)
279 {
280 
281 	if (ofw_def_impl == NULL)
282 		return (-1);
283 
284 	return (OFW_TEST(ofw_obj, name));
285 }
286 
287 int
288 OF_interpret(const char *cmd, int nreturns, ...)
289 {
290 	va_list ap;
291 	cell_t slots[16];
292 	int i = 0;
293 	int status;
294 
295 	if (ofw_def_impl == NULL)
296 		return (-1);
297 
298 	status = OFW_INTERPRET(ofw_obj, cmd, nreturns, slots);
299 	if (status == -1)
300 		return (status);
301 
302 	va_start(ap, nreturns);
303 	while (i < nreturns)
304 		*va_arg(ap, cell_t *) = slots[i++];
305 	va_end(ap);
306 
307 	return (status);
308 }
309 
310 /*
311  * Device tree functions
312  */
313 
314 /* Return the next sibling of this node or 0. */
315 phandle_t
316 OF_peer(phandle_t node)
317 {
318 
319 	if (ofw_def_impl == NULL)
320 		return (0);
321 
322 	return (OFW_PEER(ofw_obj, node));
323 }
324 
325 /* Return the first child of this node or 0. */
326 phandle_t
327 OF_child(phandle_t node)
328 {
329 
330 	if (ofw_def_impl == NULL)
331 		return (0);
332 
333 	return (OFW_CHILD(ofw_obj, node));
334 }
335 
336 /* Return the parent of this node or 0. */
337 phandle_t
338 OF_parent(phandle_t node)
339 {
340 
341 	if (ofw_def_impl == NULL)
342 		return (0);
343 
344 	return (OFW_PARENT(ofw_obj, node));
345 }
346 
347 /* Return the package handle that corresponds to an instance handle. */
348 phandle_t
349 OF_instance_to_package(ihandle_t instance)
350 {
351 
352 	if (ofw_def_impl == NULL)
353 		return (-1);
354 
355 	return (OFW_INSTANCE_TO_PACKAGE(ofw_obj, instance));
356 }
357 
358 /* Get the length of a property of a package. */
359 ssize_t
360 OF_getproplen(phandle_t package, const char *propname)
361 {
362 
363 	if (ofw_def_impl == NULL)
364 		return (-1);
365 
366 	return (OFW_GETPROPLEN(ofw_obj, package, propname));
367 }
368 
369 /* Check existence of a property of a package. */
370 int
371 OF_hasprop(phandle_t package, const char *propname)
372 {
373 
374 	return (OF_getproplen(package, propname) >= 0 ? 1 : 0);
375 }
376 
377 /* Get the value of a property of a package. */
378 ssize_t
379 OF_getprop(phandle_t package, const char *propname, void *buf, size_t buflen)
380 {
381 
382 	if (ofw_def_impl == NULL)
383 		return (-1);
384 
385 	return (OFW_GETPROP(ofw_obj, package, propname, buf, buflen));
386 }
387 
388 ssize_t
389 OF_getencprop(phandle_t node, const char *propname, pcell_t *buf, size_t len)
390 {
391 	ssize_t retval;
392 	int i;
393 
394 	KASSERT(len % 4 == 0, ("Need a multiple of 4 bytes"));
395 
396 	retval = OF_getprop(node, propname, buf, len);
397 	for (i = 0; i < len/4; i++)
398 		buf[i] = be32toh(buf[i]);
399 
400 	return (retval);
401 }
402 
403 /*
404  * Recursively search the node and its parent for the given property, working
405  * downward from the node to the device tree root.  Returns the value of the
406  * first match.
407  */
408 ssize_t
409 OF_searchprop(phandle_t node, const char *propname, void *buf, size_t len)
410 {
411 	ssize_t rv;
412 
413 	for (; node != 0; node = OF_parent(node))
414 		if ((rv = OF_getprop(node, propname, buf, len)) != -1)
415 			return (rv);
416 	return (-1);
417 }
418 
419 ssize_t
420 OF_searchencprop(phandle_t node, const char *propname, void *buf, size_t len)
421 {
422 	ssize_t rv;
423 
424 	for (; node != 0; node = OF_parent(node))
425 		if ((rv = OF_getencprop(node, propname, buf, len)) != -1)
426 			return (rv);
427 	return (-1);
428 }
429 
430 /*
431  * Store the value of a property of a package into newly allocated memory
432  * (using the M_OFWPROP malloc pool and M_WAITOK).  elsz is the size of a
433  * single element, the number of elements is return in number.
434  */
435 ssize_t
436 OF_getprop_alloc(phandle_t package, const char *propname, int elsz, void **buf)
437 {
438 	int len;
439 
440 	*buf = NULL;
441 	if ((len = OF_getproplen(package, propname)) == -1 ||
442 	    len % elsz != 0)
443 		return (-1);
444 
445 	*buf = malloc(len, M_OFWPROP, M_WAITOK);
446 	if (OF_getprop(package, propname, *buf, len) == -1) {
447 		free(*buf, M_OFWPROP);
448 		*buf = NULL;
449 		return (-1);
450 	}
451 	return (len / elsz);
452 }
453 
454 ssize_t
455 OF_getencprop_alloc(phandle_t package, const char *name, int elsz, void **buf)
456 {
457 	ssize_t retval;
458 	pcell_t *cell;
459 	int i;
460 
461 	retval = OF_getprop_alloc(package, name, elsz, buf);
462 	if (retval == -1)
463 		return (-1);
464  	if (retval * elsz % 4 != 0) {
465 		free(*buf, M_OFWPROP);
466 		*buf = NULL;
467 		return (-1);
468 	}
469 
470 	cell = *buf;
471 	for (i = 0; i < retval * elsz / 4; i++)
472 		cell[i] = be32toh(cell[i]);
473 
474 	return (retval);
475 }
476 
477 /* Get the next property of a package. */
478 int
479 OF_nextprop(phandle_t package, const char *previous, char *buf, size_t size)
480 {
481 
482 	if (ofw_def_impl == NULL)
483 		return (-1);
484 
485 	return (OFW_NEXTPROP(ofw_obj, package, previous, buf, size));
486 }
487 
488 /* Set the value of a property of a package. */
489 int
490 OF_setprop(phandle_t package, const char *propname, const void *buf, size_t len)
491 {
492 
493 	if (ofw_def_impl == NULL)
494 		return (-1);
495 
496 	return (OFW_SETPROP(ofw_obj, package, propname, buf,len));
497 }
498 
499 /* Convert a device specifier to a fully qualified pathname. */
500 ssize_t
501 OF_canon(const char *device, char *buf, size_t len)
502 {
503 
504 	if (ofw_def_impl == NULL)
505 		return (-1);
506 
507 	return (OFW_CANON(ofw_obj, device, buf, len));
508 }
509 
510 /* Return a package handle for the specified device. */
511 phandle_t
512 OF_finddevice(const char *device)
513 {
514 
515 	if (ofw_def_impl == NULL)
516 		return (-1);
517 
518 	return (OFW_FINDDEVICE(ofw_obj, device));
519 }
520 
521 /* Return the fully qualified pathname corresponding to an instance. */
522 ssize_t
523 OF_instance_to_path(ihandle_t instance, char *buf, size_t len)
524 {
525 
526 	if (ofw_def_impl == NULL)
527 		return (-1);
528 
529 	return (OFW_INSTANCE_TO_PATH(ofw_obj, instance, buf, len));
530 }
531 
532 /* Return the fully qualified pathname corresponding to a package. */
533 ssize_t
534 OF_package_to_path(phandle_t package, char *buf, size_t len)
535 {
536 
537 	if (ofw_def_impl == NULL)
538 		return (-1);
539 
540 	return (OFW_PACKAGE_TO_PATH(ofw_obj, package, buf, len));
541 }
542 
543 /* Look up effective phandle (see FDT/PAPR spec) */
544 static phandle_t
545 OF_child_xref_phandle(phandle_t parent, phandle_t xref)
546 {
547 	phandle_t child, rxref;
548 
549 	/*
550 	 * Recursively descend from parent, looking for a node with a property
551 	 * named either "phandle", "ibm,phandle", or "linux,phandle" that
552 	 * matches the xref we are looking for.
553 	 */
554 
555 	for (child = OF_child(parent); child != 0; child = OF_peer(child)) {
556 		rxref = OF_child_xref_phandle(child, xref);
557 		if (rxref != -1)
558 			return (rxref);
559 
560 		if (OF_getencprop(child, "phandle", &rxref, sizeof(rxref)) ==
561 		    -1 && OF_getencprop(child, "ibm,phandle", &rxref,
562 		    sizeof(rxref)) == -1 && OF_getencprop(child,
563 		    "linux,phandle", &rxref, sizeof(rxref)) == -1)
564 			continue;
565 
566 		if (rxref == xref)
567 			return (child);
568 	}
569 
570 	return (-1);
571 }
572 
573 phandle_t
574 OF_node_from_xref(phandle_t xref)
575 {
576 	struct xrefinfo *xi;
577 	phandle_t node;
578 
579 	if (xref_init_done) {
580 		if ((xi = xrefinfo_find(xref, FIND_BY_XREF)) == NULL)
581 			return (xref);
582 		return (xi->node);
583 	}
584 
585 	if ((node = OF_child_xref_phandle(OF_peer(0), xref)) == -1)
586 		return (xref);
587 	return (node);
588 }
589 
590 phandle_t
591 OF_xref_from_node(phandle_t node)
592 {
593 	struct xrefinfo *xi;
594 	phandle_t xref;
595 
596 	if (xref_init_done) {
597 		if ((xi = xrefinfo_find(node, FIND_BY_NODE)) == NULL)
598 			return (node);
599 		return (xi->xref);
600 	}
601 
602 	if (OF_getencprop(node, "phandle", &xref, sizeof(xref)) ==
603 	    -1 && OF_getencprop(node, "ibm,phandle", &xref,
604 	    sizeof(xref)) == -1 && OF_getencprop(node,
605 	    "linux,phandle", &xref, sizeof(xref)) == -1)
606 		return (node);
607 	return (xref);
608 }
609 
610 device_t
611 OF_device_from_xref(phandle_t xref)
612 {
613 	struct xrefinfo *xi;
614 
615 	if (xref_init_done) {
616 		if ((xi = xrefinfo_find(xref, FIND_BY_XREF)) == NULL)
617 			return (NULL);
618 		return (xi->dev);
619 	}
620 	panic("Attempt to find device before xreflist_init");
621 }
622 
623 phandle_t
624 OF_xref_from_device(device_t dev)
625 {
626 	struct xrefinfo *xi;
627 
628 	if (xref_init_done) {
629 		if ((xi = xrefinfo_find((uintptr_t)dev, FIND_BY_DEV)) == NULL)
630 			return (0);
631 		return (xi->xref);
632 	}
633 	panic("Attempt to find xref before xreflist_init");
634 }
635 
636 int
637 OF_device_register_xref(phandle_t xref, device_t dev)
638 {
639 	struct xrefinfo *xi;
640 
641 	/*
642 	 * If the given xref handle doesn't already exist in the list then we
643 	 * add a list entry.  In theory this can only happen on a system where
644 	 * nodes don't contain phandle properties and xref and node handles are
645 	 * synonymous, so the xref handle is added as the node handle as well.
646 	 */
647 	if (xref_init_done) {
648 		if ((xi = xrefinfo_find(xref, FIND_BY_XREF)) == NULL)
649 			xrefinfo_add(xref, xref, dev);
650 		else
651 			xi->dev = dev;
652 		return (0);
653 	}
654 	panic("Attempt to register device before xreflist_init");
655 }
656 
657 /*  Call the method in the scope of a given instance. */
658 int
659 OF_call_method(const char *method, ihandle_t instance, int nargs, int nreturns,
660     ...)
661 {
662 	va_list ap;
663 	cell_t args_n_results[12];
664 	int n, status;
665 
666 	if (nargs > 6 || ofw_def_impl == NULL)
667 		return (-1);
668 	va_start(ap, nreturns);
669 	for (n = 0; n < nargs; n++)
670 		args_n_results[n] = va_arg(ap, cell_t);
671 
672 	status = OFW_CALL_METHOD(ofw_obj, instance, method, nargs, nreturns,
673 	    args_n_results);
674 	if (status != 0)
675 		return (status);
676 
677 	for (; n < nargs + nreturns; n++)
678 		*va_arg(ap, cell_t *) = args_n_results[n];
679 	va_end(ap);
680 	return (0);
681 }
682 
683 /*
684  * Device I/O functions
685  */
686 
687 /* Open an instance for a device. */
688 ihandle_t
689 OF_open(const char *device)
690 {
691 
692 	if (ofw_def_impl == NULL)
693 		return (0);
694 
695 	return (OFW_OPEN(ofw_obj, device));
696 }
697 
698 /* Close an instance. */
699 void
700 OF_close(ihandle_t instance)
701 {
702 
703 	if (ofw_def_impl == NULL)
704 		return;
705 
706 	OFW_CLOSE(ofw_obj, instance);
707 }
708 
709 /* Read from an instance. */
710 ssize_t
711 OF_read(ihandle_t instance, void *addr, size_t len)
712 {
713 
714 	if (ofw_def_impl == NULL)
715 		return (-1);
716 
717 	return (OFW_READ(ofw_obj, instance, addr, len));
718 }
719 
720 /* Write to an instance. */
721 ssize_t
722 OF_write(ihandle_t instance, const void *addr, size_t len)
723 {
724 
725 	if (ofw_def_impl == NULL)
726 		return (-1);
727 
728 	return (OFW_WRITE(ofw_obj, instance, addr, len));
729 }
730 
731 /* Seek to a position. */
732 int
733 OF_seek(ihandle_t instance, uint64_t pos)
734 {
735 
736 	if (ofw_def_impl == NULL)
737 		return (-1);
738 
739 	return (OFW_SEEK(ofw_obj, instance, pos));
740 }
741 
742 /*
743  * Memory functions
744  */
745 
746 /* Claim an area of memory. */
747 void *
748 OF_claim(void *virt, size_t size, u_int align)
749 {
750 
751 	if (ofw_def_impl == NULL)
752 		return ((void *)-1);
753 
754 	return (OFW_CLAIM(ofw_obj, virt, size, align));
755 }
756 
757 /* Release an area of memory. */
758 void
759 OF_release(void *virt, size_t size)
760 {
761 
762 	if (ofw_def_impl == NULL)
763 		return;
764 
765 	OFW_RELEASE(ofw_obj, virt, size);
766 }
767 
768 /*
769  * Control transfer functions
770  */
771 
772 /* Suspend and drop back to the Open Firmware interface. */
773 void
774 OF_enter()
775 {
776 
777 	if (ofw_def_impl == NULL)
778 		return;
779 
780 	OFW_ENTER(ofw_obj);
781 }
782 
783 /* Shut down and drop back to the Open Firmware interface. */
784 void
785 OF_exit()
786 {
787 
788 	if (ofw_def_impl == NULL)
789 		panic("OF_exit: Open Firmware not available");
790 
791 	/* Should not return */
792 	OFW_EXIT(ofw_obj);
793 
794 	for (;;)			/* just in case */
795 		;
796 }
797