Add an Open Firmware access module for real-mode OF accesses to the PowerPC

build. This is required for the IBM Mambo simulator, as well as a variety
of non-Apple PowerPC hardware.

1 files changed, 922 insertions, 0 deletions

diff --git a/sys/powerpc/ofw/ofw_real.c b/sys/powerpc/ofw/ofw_real.c
new file mode 100644
index 0000000..c5f11b0
--- /dev/null
+++ b/sys/powerpc/ofw/ofw_real.c
@@ -0,0 +1,922 @@
+/*	$NetBSD: Locore.c,v 1.7 2000/08/20 07:04:59 tsubai Exp $	*/
+
+/*-
+ * Copyright (C) 1995, 1996 Wolfgang Solfrank.
+ * Copyright (C) 1995, 1996 TooLs GmbH.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by TooLs GmbH.
+ * 4. The name of TooLs GmbH may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+/*-
+ * Copyright (C) 2000 Benno Rice.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Benno Rice ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/systm.h>
+
+#include <vm/vm.h>
+#include <vm/pmap.h>
+
+#include <machine/stdarg.h>
+#include <machine/bus.h>
+#include <machine/pmap.h>
+#include <machine/ofw_machdep.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofwvar.h>
+#include "ofw_if.h"
+
+static void ofw_real_init(ofw_t, void *openfirm);
+static int ofw_real_test(ofw_t, const char *name);
+static phandle_t ofw_real_peer(ofw_t, phandle_t node);
+static phandle_t ofw_real_child(ofw_t, phandle_t node);
+static phandle_t ofw_real_parent(ofw_t, phandle_t node);
+static phandle_t ofw_real_instance_to_package(ofw_t, ihandle_t instance);
+static ssize_t ofw_real_getproplen(ofw_t, phandle_t package, 
+    const char *propname);
+static ssize_t ofw_real_getprop(ofw_t, phandle_t package, const char *propname, 
+    void *buf, size_t buflen);
+static int ofw_real_nextprop(ofw_t, phandle_t package, const char *previous, 
+    char *buf, size_t);
+static int ofw_real_setprop(ofw_t, phandle_t package, char *propname, 
+    void *buf, size_t len);
+static ssize_t ofw_real_canon(ofw_t, const char *device, char *buf, size_t len);
+static phandle_t ofw_real_finddevice(ofw_t, const char *device);
+static ssize_t ofw_real_instance_to_path(ofw_t, ihandle_t instance, char *buf, 
+    size_t len);
+static ssize_t ofw_real_package_to_path(ofw_t, phandle_t package, char *buf, 
+    size_t len);
+static int ofw_real_call_method(ofw_t, ihandle_t instance, const char *method, 
+    int nargs, int nreturns, unsigned long *args_and_returns);
+static ihandle_t ofw_real_open(ofw_t, const char *device);
+static void ofw_real_close(ofw_t, ihandle_t instance);
+static ssize_t ofw_real_read(ofw_t, ihandle_t instance, void *addr, size_t len);
+static ssize_t ofw_real_write(ofw_t, ihandle_t instance, const void *addr, 
+    size_t len);
+static int ofw_real_seek(ofw_t, ihandle_t instance, u_int64_t pos);
+static caddr_t ofw_real_claim(ofw_t, void *virt, size_t size, u_int align);
+static void ofw_real_release(ofw_t, void *virt, size_t size);
+static void ofw_real_enter(ofw_t);
+static void ofw_real_exit(ofw_t);
+
+static ofw_method_t ofw_real_methods[] = {
+	OFWMETHOD(ofw_init,			ofw_real_init),
+	OFWMETHOD(ofw_peer,			ofw_real_peer),
+	OFWMETHOD(ofw_child,			ofw_real_child),
+	OFWMETHOD(ofw_parent,			ofw_real_parent),
+	OFWMETHOD(ofw_instance_to_package,	ofw_real_instance_to_package),
+	OFWMETHOD(ofw_getproplen,		ofw_real_getproplen),
+	OFWMETHOD(ofw_getprop,			ofw_real_getprop),
+	OFWMETHOD(ofw_nextprop,			ofw_real_nextprop),
+	OFWMETHOD(ofw_setprop,			ofw_real_setprop),
+	OFWMETHOD(ofw_canon,			ofw_real_canon),
+	OFWMETHOD(ofw_finddevice,		ofw_real_finddevice),
+	OFWMETHOD(ofw_instance_to_path,		ofw_real_instance_to_path),
+	OFWMETHOD(ofw_package_to_path,		ofw_real_package_to_path),
+
+	OFWMETHOD(ofw_test,			ofw_real_test),
+	OFWMETHOD(ofw_call_method,		ofw_real_call_method),
+	OFWMETHOD(ofw_open,			ofw_real_open),
+	OFWMETHOD(ofw_close,			ofw_real_close),
+	OFWMETHOD(ofw_read,			ofw_real_read),
+	OFWMETHOD(ofw_write,			ofw_real_write),
+	OFWMETHOD(ofw_seek,			ofw_real_seek),
+	OFWMETHOD(ofw_claim,			ofw_real_claim),
+	OFWMETHOD(ofw_release,			ofw_real_release),
+	OFWMETHOD(ofw_enter,			ofw_real_enter),
+	OFWMETHOD(ofw_exit,			ofw_real_exit),
+
+	{ 0, 0 }
+};
+
+static ofw_def_t ofw_real = {
+	OFW_STD_REAL,
+	ofw_real_methods,
+	0
+};
+OFW_DEF(ofw_real);
+
+MALLOC_DEFINE(M_OFWREAL, "ofwreal", "Open Firmware Real Mode Bounce Page");
+
+static int (*openfirmware)(void *);
+
+static vm_offset_t	of_bounce_phys;
+static caddr_t		of_bounce_virt;
+static off_t		of_bounce_offset;
+static size_t		of_bounce_size;
+static struct mtx	of_bounce_mtx;
+
+/*
+ * After the VM is up, allocate a wired, low memory bounce page.
+ */
+
+static void ofw_real_bounce_alloc(void *);
+
+SYSINIT(ofw_real_bounce_alloc, SI_SUB_VM, SI_ORDER_ANY, 
+    ofw_real_bounce_alloc, NULL);
+
+static void
+ofw_real_start(void)
+{
+	mtx_lock(&of_bounce_mtx);
+	of_bounce_offset = 0;
+}
+	
+static void
+ofw_real_stop(void)
+{
+	mtx_unlock(&of_bounce_mtx);
+}
+
+static void
+ofw_real_bounce_alloc(void *junk)
+{
+	/*
+	 * Check that ofw_real is actually in use before allocating wads 
+	 * of memory. Do this by checking if our mutex has been set up.
+	 */
+	if (!mtx_initialized(&of_bounce_mtx))
+		return;
+
+	/*
+	 * Allocate a page of contiguous, wired physical memory that can
+	 * fit into a 32-bit address space.
+	 */
+
+	mtx_lock(&of_bounce_mtx);
+
+	of_bounce_virt = contigmalloc(PAGE_SIZE, M_OFWREAL, 0,
+			     0, BUS_SPACE_MAXADDR_32BIT, PAGE_SIZE, PAGE_SIZE);
+	of_bounce_phys = vtophys(of_bounce_virt);
+	of_bounce_size = PAGE_SIZE;
+
+	mtx_unlock(&of_bounce_mtx);
+}
+
+static cell_t
+ofw_real_map(const void *buf, size_t len)
+{
+	cell_t phys;
+
+	mtx_assert(&of_bounce_mtx, MA_OWNED);
+
+	if (of_bounce_virt == NULL) {
+		if (!pmap_bootstrapped)
+			return (cell_t)buf;
+
+		/*
+		 * XXX: It is possible for us to get called before the VM has
+		 * come online, but after the MMU is up. We don't have the
+		 * bounce buffer yet, but can no longer presume a 1:1 mapping.
+		 * Grab the physical address of the buffer, and hope it is
+		 * in range if this happens.
+		 */
+		return (cell_t)vtophys(buf);
+	}
+
+	/*
+	 * Make sure the bounce page offset satisfies any reasonable
+	 * alignment constraint.
+	 */
+	of_bounce_offset += of_bounce_offset % sizeof(register_t);
+
+	if (of_bounce_offset + len > of_bounce_size) {
+		panic("Oversize Open Firmware call!");
+		return 0;
+	}
+
+	memcpy(of_bounce_virt + of_bounce_offset, buf, len);
+	phys = of_bounce_phys + of_bounce_offset;
+
+	of_bounce_offset += len;
+
+	return phys;
+}
+
+static void
+ofw_real_unmap(cell_t physaddr, void *buf, size_t len)
+{
+	mtx_assert(&of_bounce_mtx, MA_OWNED);
+
+	if (of_bounce_virt == NULL)
+		return;
+
+	memcpy(buf,of_bounce_virt + (physaddr - of_bounce_phys),len);
+}
+
+/* Initialiser */
+
+static void
+ofw_real_init(ofw_t ofw, void *openfirm)
+{
+	openfirmware = (int (*)(void *))openfirm;
+
+	mtx_init(&of_bounce_mtx, "OF Bounce Page", MTX_DEF, 0);
+	of_bounce_virt = NULL;
+}
+
+/*
+ * Generic functions
+ */
+
+/* Test to see if a service exists. */
+static int
+ofw_real_test(ofw_t ofw, const char *name)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t service;
+		cell_t missing;
+	} args = {
+		(cell_t)"test",
+		1,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.service = ofw_real_map(name, strlen(name) + 1);
+	if (args.service == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_stop();
+	return (args.missing);
+}
+
+/*
+ * Device tree functions
+ */
+
+/* Return the next sibling of this node or 0. */
+static phandle_t
+ofw_real_peer(ofw_t ofw, phandle_t node)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t node;
+		cell_t next;
+	} args = {
+		(cell_t)"peer",
+		1,
+		1,
+	};
+
+	args.node = node;
+	if (openfirmware(&args) == -1)
+		return (-1);
+	return (args.next);
+}
+
+/* Return the first child of this node or 0. */
+static phandle_t
+ofw_real_child(ofw_t ofw, phandle_t node)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t node;
+		cell_t child;
+	} args = {
+		(cell_t)"child",
+		1,
+		1,
+	};
+
+	args.node = node;
+	if (openfirmware(&args) == -1)
+		return (-1);
+	return (args.child);
+}
+
+/* Return the parent of this node or 0. */
+static phandle_t
+ofw_real_parent(ofw_t ofw, phandle_t node)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t node;
+		cell_t parent;
+	} args = {
+		(cell_t)"parent",
+		1,
+		1,
+	};
+
+	args.node = node;
+	if (openfirmware(&args) == -1)
+		return (-1);
+	return (args.parent);
+}
+
+/* Return the package handle that corresponds to an instance handle. */
+static phandle_t
+ofw_real_instance_to_package(ofw_t ofw, ihandle_t instance)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t instance;
+		cell_t package;
+	} args = {
+		(cell_t)"instance-to-package",
+		1,
+		1,
+	};
+
+	args.instance = instance;
+	if (openfirmware(&args) == -1)
+		return (-1);
+	return (args.package);
+}
+
+/* Get the length of a property of a package. */
+static ssize_t
+ofw_real_getproplen(ofw_t ofw, phandle_t package, const char *propname)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t package;
+		cell_t propname;
+		cell_t proplen;
+	} args = {
+		(cell_t)"getproplen",
+		2,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.package = package;
+	args.propname = ofw_real_map(propname, strlen(propname) + 1);
+	if (args.propname == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_stop();
+	return (args.proplen);
+}
+
+/* Get the value of a property of a package. */
+static ssize_t
+ofw_real_getprop(ofw_t ofw, phandle_t package, const char *propname, void *buf, 
+    size_t buflen)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t package;
+		cell_t propname;
+		cell_t buf;
+		cell_t buflen;
+		cell_t size;
+	} args = {
+		(cell_t)"getprop",
+		4,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.package = package;
+	args.propname = ofw_real_map(propname, strlen(propname) + 1);
+	args.buf = ofw_real_map(buf, buflen);
+	args.buflen = buflen;
+	if (args.propname == 0 || args.buf == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_unmap(args.buf, buf, buflen);
+
+	ofw_real_stop();
+	return (args.size);
+}
+
+/* Get the next property of a package. */
+static int
+ofw_real_nextprop(ofw_t ofw, phandle_t package, const char *previous, 
+    char *buf, size_t size)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t package;
+		cell_t previous;
+		cell_t buf;
+		cell_t flag;
+	} args = {
+		(cell_t)"nextprop",
+		3,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.package = package;
+	args.previous = ofw_real_map(previous, strlen(previous) + 1);
+	args.buf = ofw_real_map(buf, size);
+	if (args.previous == 0 || args.buf == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_unmap(args.buf, buf, size);
+
+	ofw_real_stop();
+	return (args.flag);
+}
+
+/* Set the value of a property of a package. */
+/* XXX Has a bug on FirePower */
+static int
+ofw_real_setprop(ofw_t ofw, phandle_t package, char *propname, void *buf, 
+    size_t len)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t package;
+		cell_t propname;
+		cell_t buf;
+		cell_t len;
+		cell_t size;
+	} args = {
+		(cell_t)"setprop",
+		4,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.package = package;
+	args.propname = ofw_real_map(propname, strlen(propname) + 1);
+	args.buf = ofw_real_map(buf, len);
+	args.len = len;
+	if (args.propname == 0 || args.buf == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_stop();
+	return (args.size);
+}
+
+/* Convert a device specifier to a fully qualified pathname. */
+static ssize_t
+ofw_real_canon(ofw_t ofw, const char *device, char *buf, size_t len)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t device;
+		cell_t buf;
+		cell_t len;
+		cell_t size;
+	} args = {
+		(cell_t)"canon",
+		3,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.device = ofw_real_map(device, strlen(device) + 1);
+	args.buf = ofw_real_map(buf, len);
+	args.len = len;
+	if (args.device == 0 || args.buf == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_unmap(args.buf, buf, len);
+
+	ofw_real_stop();
+	return (args.size);
+}
+
+/* Return a package handle for the specified device. */
+static phandle_t
+ofw_real_finddevice(ofw_t ofw, const char *device)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t device;
+		cell_t package;
+	} args = {
+		(cell_t)"finddevice",
+		1,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.device = ofw_real_map(device, strlen(device) + 1);
+	if (args.device == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_stop();
+	return (args.package);
+}
+
+/* Return the fully qualified pathname corresponding to an instance. */
+static ssize_t
+ofw_real_instance_to_path(ofw_t ofw, ihandle_t instance, char *buf, size_t len)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t instance;
+		cell_t buf;
+		cell_t len;
+		cell_t size;
+	} args = {
+		(cell_t)"instance-to-path",
+		3,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.instance = instance;
+	args.buf = ofw_real_map(buf, len);
+	args.len = len;
+	if (args.buf == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_unmap(args.buf, buf, len);
+
+	ofw_real_stop();
+	return (args.size);
+}
+
+/* Return the fully qualified pathname corresponding to a package. */
+static ssize_t
+ofw_real_package_to_path(ofw_t ofw, phandle_t package, char *buf, size_t len)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t package;
+		cell_t buf;
+		cell_t len;
+		cell_t size;
+	} args = {
+		(cell_t)"package-to-path",
+		3,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.package = package;
+	args.buf = ofw_real_map(buf, len);
+	args.len = len;
+	if (args.buf == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_unmap(args.buf, buf, len);
+
+	ofw_real_stop();
+	return (args.size);
+}
+
+/*  Call the method in the scope of a given instance. */
+static int
+ofw_real_call_method(ofw_t ofw, ihandle_t instance, const char *method, 
+    int nargs, int nreturns, unsigned long *args_and_returns)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t method;
+		cell_t instance;
+		cell_t args_n_results[12];
+	} args = {
+		(cell_t)"call-method",
+		2,
+		1,
+	};
+	cell_t *cp;
+	unsigned long *ap;
+	int n;
+
+	if (nargs > 6)
+		return (-1);
+
+	ofw_real_start();
+	args.nargs = nargs + 2;
+	args.nreturns = nreturns + 1;
+	args.method = ofw_real_map(method, strlen(method) + 1);
+	args.instance = instance;
+
+	ap = args_and_returns;
+	for (cp = args.args_n_results + (n = nargs); --n >= 0;)
+		*--cp = *(ap++);
+	if (args.method == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_stop();
+	if (args.args_n_results[nargs])
+		return (args.args_n_results[nargs]);
+	for (cp = args.args_n_results + nargs + (n = args.nreturns); --n > 0;)
+		*(ap++) = *--cp;
+	return (0);
+}
+
+/*
+ * Device I/O functions
+ */
+
+/* Open an instance for a device. */
+static ihandle_t
+ofw_real_open(ofw_t ofw, const char *device)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t device;
+		cell_t instance;
+	} args = {
+		(cell_t)"open",
+		1,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.device = ofw_real_map(device, strlen(device) + 1);
+	if (args.device == 0 || openfirmware(&args) == -1 
+	    || args.instance == 0) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_stop();
+	return (args.instance);
+}
+
+/* Close an instance. */
+static void
+ofw_real_close(ofw_t ofw, ihandle_t instance)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t instance;
+	} args = {
+		(cell_t)"close",
+		1,
+	};
+
+	args.instance = instance;
+	openfirmware(&args);
+}
+
+/* Read from an instance. */
+static ssize_t
+ofw_real_read(ofw_t ofw, ihandle_t instance, void *addr, size_t len)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t instance;
+		cell_t addr;
+		cell_t len;
+		cell_t actual;
+	} args = {
+		(cell_t)"read",
+		3,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.instance = instance;
+	args.addr = ofw_real_map(addr, len);
+	args.len = len;
+	if (args.addr == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_unmap(args.addr, addr, len);
+
+	ofw_real_stop();
+	return (args.actual);
+}
+
+/* Write to an instance. */
+static ssize_t
+ofw_real_write(ofw_t ofw, ihandle_t instance, const void *addr, size_t len)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t instance;
+		cell_t addr;
+		cell_t len;
+		cell_t actual;
+	} args = {
+		(cell_t)"write",
+		3,
+		1,
+	};
+
+	ofw_real_start();
+
+	args.instance = instance;
+	args.addr = ofw_real_map(addr, len);
+	args.len = len;
+	if (args.addr == 0 || openfirmware(&args) == -1) {
+		ofw_real_stop();
+		return (-1);
+	}
+	ofw_real_stop();
+	return (args.actual);
+}
+
+/* Seek to a position. */
+static int
+ofw_real_seek(ofw_t ofw, ihandle_t instance, u_int64_t pos)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t instance;
+		cell_t poshi;
+		cell_t poslo;
+		cell_t status;
+	} args = {
+		(cell_t)"seek",
+		3,
+		1,
+	};
+
+	args.instance = instance;
+	args.poshi = pos >> 32;
+	args.poslo = pos;
+	if (openfirmware(&args) == -1)
+		return (-1);
+	return (args.status);
+}
+
+/*
+ * Memory functions
+ */
+
+/* Claim an area of memory. */
+static caddr_t
+ofw_real_claim(ofw_t ofw, void *virt, size_t size, u_int align)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t virt;
+		cell_t size;
+		cell_t align;
+		cell_t baseaddr;
+	} args = {
+		(cell_t)"claim",
+		3,
+		1,
+	};
+
+	args.virt = (cell_t)virt;
+	args.size = size;
+	args.align = align;
+	if (openfirmware(&args) == -1)
+		return ((void *)-1);
+	return ((void *)args.baseaddr);
+}
+
+/* Release an area of memory. */
+static void
+ofw_real_release(ofw_t ofw, void *virt, size_t size)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+		cell_t virt;
+		cell_t size;
+	} args = {
+		(cell_t)"release",
+		2,
+	};
+
+	args.virt = (cell_t)virt;
+	args.size = size;
+	openfirmware(&args);
+}
+
+/*
+ * Control transfer functions
+ */
+
+/* Suspend and drop back to the Open Firmware interface. */
+static void
+ofw_real_enter(ofw_t ofw)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+	} args = {
+		(cell_t)"enter",
+	};
+
+	openfirmware(&args);
+	/* We may come back. */
+}
+
+/* Shut down and drop back to the Open Firmware interface. */
+static void
+ofw_real_exit(ofw_t ofw)
+{
+	static struct {
+		cell_t name;
+		cell_t nargs;
+		cell_t nreturns;
+	} args = {
+		(cell_t)"exit",
+	};
+
+	openfirmware(&args);
+	for (;;)			/* just in case */
+		;
+}
+