Add front-ends for the 'lebuffer' variants found on some SBus cards.

These are shared-memory variants based on Am79C90-compatible chips
that apart from the missing DMA engine are similar to the 'ledma'
variant including using a (pseudo-)bus/device for the buffer that
the actual LANCE device hangs off from. The performance of these is
close to that of the 'ledma' one, like expected at a few times the
CPU load though.

2 files changed, 708 insertions, 0 deletions

diff --git a/sys/dev/le/if_le_lebuffer.c b/sys/dev/le/if_le_lebuffer.c
new file mode 100644
index 0000000..6c3d367
--- /dev/null
+++ b/sys/dev/le/if_le_lebuffer.c
@@ -0,0 +1,408 @@
+/*-
+ * Copyright (c) 2006 Marius Strobl <marius@FreeBSD.org>
+ * 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 THE AUTHOR AND CONTRIBUTORS ``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 THE AUTHOR OR CONTRIBUTORS 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/systm.h>
+#include <sys/bus.h>
+#include <sys/endian.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/module.h>
+#include <sys/mutex.h>
+#include <sys/resource.h>
+#include <sys/rman.h>
+#include <sys/socket.h>
+
+#include <dev/ofw/ofw_bus.h>
+
+#include <machine/bus.h>
+#include <machine/ofw_machdep.h>
+#include <machine/resource.h>
+
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <net/if_media.h>
+
+#include <dev/le/lancereg.h>
+#include <dev/le/lancevar.h>
+#include <dev/le/am7990reg.h>
+#include <dev/le/am7990var.h>
+
+/*
+ * LANCE registers
+ */
+#define	LEREG1_RDP	0	/* Register Data port */
+#define	LEREG1_RAP	2	/* Register Address port */
+
+struct le_lebuffer_softc {
+	struct am7990_softc	sc_am7990;	/* glue to MI code */
+
+	int			sc_brid;
+	struct resource		*sc_bres;
+	bus_space_tag_t		sc_buft;
+	bus_space_handle_t	sc_bufh;
+
+	int			sc_rrid;
+	struct resource		*sc_rres;
+	bus_space_tag_t		sc_regt;
+	bus_space_handle_t	sc_regh;
+
+	int			sc_irid;
+	struct resource		*sc_ires;
+	void			*sc_ih;
+};
+
+static devclass_t le_lebuffer_devclass;
+
+static device_probe_t le_lebuffer_probe;
+static device_attach_t le_lebuffer_attach;
+static device_detach_t le_lebuffer_detach;
+static device_resume_t le_buffer_resume;
+static device_suspend_t le_buffer_suspend;
+
+static device_method_t le_lebuffer_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_probe,		le_lebuffer_probe),
+	DEVMETHOD(device_attach,	le_lebuffer_attach),
+	DEVMETHOD(device_detach,	le_lebuffer_detach),
+	/* We can just use the suspend method here. */
+	DEVMETHOD(device_shutdown,	le_buffer_suspend),
+	DEVMETHOD(device_suspend,	le_buffer_suspend),
+	DEVMETHOD(device_resume,	le_buffer_resume),
+
+	{ 0, 0 }
+};
+
+DEFINE_CLASS_0(le, le_lebuffer_driver, le_lebuffer_methods,
+    sizeof(struct le_lebuffer_softc));
+DRIVER_MODULE(le, lebuffer, le_lebuffer_driver, le_lebuffer_devclass, 0, 0);
+MODULE_DEPEND(le, ether, 1, 1, 1);
+
+/*
+ * Media types supported
+ */
+static const int le_lebuffer_media[] = {
+	IFM_MAKEWORD(IFM_ETHER, IFM_10_T, 0, 0)
+};
+#define	NLEMEDIA							\
+    (sizeof(le_lebuffer_media) / sizeof(le_lebuffer_media[0]))
+
+static void le_lebuffer_wrcsr(struct lance_softc *, uint16_t, uint16_t);
+static uint16_t le_lebuffer_rdcsr(struct lance_softc *, uint16_t);
+static void le_lebuffer_copytodesc(struct lance_softc *, void *, int, int);
+static void le_lebuffer_copyfromdesc(struct lance_softc *, void *, int, int);
+static void le_lebuffer_copytobuf(struct lance_softc *, void *, int, int);
+static void le_lebuffer_copyfrombuf(struct lance_softc *, void *, int, int);
+static void le_lebuffer_zerobuf(struct lance_softc *, int, int);
+
+static void
+le_lebuffer_wrcsr(struct lance_softc *sc, uint16_t port, uint16_t val)
+{
+	struct le_lebuffer_softc *lesc = (struct le_lebuffer_softc *)sc;
+
+	bus_space_write_2(lesc->sc_regt, lesc->sc_regh, LEREG1_RAP, port);
+	bus_space_barrier(lesc->sc_regt, lesc->sc_regh, LEREG1_RAP, 2,
+	    BUS_SPACE_BARRIER_WRITE);
+	bus_space_write_2(lesc->sc_regt, lesc->sc_regh, LEREG1_RDP, val);
+}
+
+static uint16_t
+le_lebuffer_rdcsr(struct lance_softc *sc, uint16_t port)
+{
+	struct le_lebuffer_softc *lesc = (struct le_lebuffer_softc *)sc;
+
+	bus_space_write_2(lesc->sc_regt, lesc->sc_regh, LEREG1_RAP, port);
+	bus_space_barrier(lesc->sc_regt, lesc->sc_regh, LEREG1_RAP, 2,
+	    BUS_SPACE_BARRIER_WRITE);
+	return (bus_space_read_2(lesc->sc_regt, lesc->sc_regh, LEREG1_RDP));
+}
+
+/*
+ * It turns out that using bus_space(9) to access the buffers and the
+ * descriptors yields way more throughput than accessing them via the
+ * KVA returned by rman_get_virtual(9). The descriptor rings can be
+ * accessed using 8-bit up to 64-bit operations while the buffers can
+ * be only accessed using 8-bit and 16-bit operations.
+ * NB:	For whatever reason setting LE_C3_BSWP has no effect with at
+ *	least the 501-2981 (although their 'busmaster-regval' property
+ *	indicates to set LE_C3_BSWP also for these cards), so we need
+ *	to manually byte swap access to the buffers, i.e. the accesses
+ *	going through the RX/TX FIFOs.
+ */
+
+static void
+le_lebuffer_copytodesc(struct lance_softc *sc, void *fromv, int off, int len)
+{
+	struct le_lebuffer_softc *lesc = (struct le_lebuffer_softc *)sc;
+	caddr_t from = fromv;
+
+	for (; len >= 8; len -= 8, off += 8, from += 8)
+		bus_space_write_8(lesc->sc_buft, lesc->sc_bufh, off,
+		    be64dec(from));
+	for (; len >= 4; len -= 4, off += 4, from += 4)
+		bus_space_write_4(lesc->sc_buft, lesc->sc_bufh, off,
+		    be32dec(from));
+	for (; len >= 2; len -= 2, off += 2, from += 2)
+		bus_space_write_2(lesc->sc_buft, lesc->sc_bufh, off,
+		    be16dec(from));
+	if (len == 1)
+		bus_space_write_1(lesc->sc_buft, lesc->sc_bufh, off,
+		    *from);
+}
+
+static void
+le_lebuffer_copyfromdesc(struct lance_softc *sc, void *tov, int off, int len)
+{
+	struct le_lebuffer_softc *lesc = (struct le_lebuffer_softc *)sc;
+	caddr_t to = tov;
+
+	for (; len >= 8; len -= 8, off += 8, to += 8)
+		be64enc(to,
+		    bus_space_read_8(lesc->sc_buft, lesc->sc_bufh, off));
+	for (; len >= 4; len -= 4, off += 4, to += 4)
+		be32enc(to,
+		    bus_space_read_4(lesc->sc_buft, lesc->sc_bufh, off));
+	for (; len >= 2; len -= 2, off += 2, to += 2)
+		be16enc(to,
+		    bus_space_read_2(lesc->sc_buft, lesc->sc_bufh, off));
+	if (len == 1)
+		*to =
+		    bus_space_read_1(lesc->sc_buft, lesc->sc_bufh, off);
+}
+
+static void
+le_lebuffer_copytobuf(struct lance_softc *sc, void *fromv, int off, int len)
+{
+	struct le_lebuffer_softc *lesc = (struct le_lebuffer_softc *)sc;
+	caddr_t from = fromv;
+
+	for (; len >= 2; len -= 2, off += 2, from += 2)
+		bus_space_write_2(lesc->sc_buft, lesc->sc_bufh, off,
+		    le16dec(from));
+	if (len == 1)
+		bus_space_write_1(lesc->sc_buft, lesc->sc_bufh, off + 1,
+		    *from);
+}
+
+static void
+le_lebuffer_copyfrombuf(struct lance_softc *sc, void *tov, int off, int len)
+{
+	struct le_lebuffer_softc *lesc = (struct le_lebuffer_softc *)sc;
+	caddr_t to = tov;
+
+	for (; len >= 2; len -= 2, off += 2, to += 2)
+		le16enc(to,
+		    bus_space_read_2(lesc->sc_buft, lesc->sc_bufh, off));
+	if (len == 1)
+		*to =
+		    bus_space_read_1(lesc->sc_buft, lesc->sc_bufh, off + 1);
+}
+
+static void
+le_lebuffer_zerobuf(struct lance_softc *sc, int off, int len)
+{
+	struct le_lebuffer_softc *lesc = (struct le_lebuffer_softc *)sc;
+
+	for (; len >= 2; len -= 2, off += 2)
+		bus_space_write_2(lesc->sc_buft, lesc->sc_bufh, off, 0);
+	if (len == 1)
+		bus_space_write_1(lesc->sc_buft, lesc->sc_bufh, off + 1, 0);
+}
+
+static int
+le_lebuffer_probe(device_t dev)
+{
+
+	if (strcmp(ofw_bus_get_name(dev), "le") == 0) {
+		device_set_desc(dev, "LANCE Ethernet");
+		return (BUS_PROBE_DEFAULT);
+	}
+	return (ENXIO);
+}
+
+static int
+le_lebuffer_attach(device_t dev)
+{
+	struct le_lebuffer_softc *lesc;
+	struct lance_softc *sc;
+	int error;
+
+	lesc = device_get_softc(dev);
+	sc = &lesc->sc_am7990.lsc;
+
+	LE_LOCK_INIT(sc, device_get_nameunit(dev));
+
+	/*
+	 * The "register space" of the parent is just a buffer where the
+	 * the LANCE descriptor rings and the RX/TX buffers can be stored.
+	 */
+	lesc->sc_brid = 0;
+	lesc->sc_bres = bus_alloc_resource_any(device_get_parent(dev),
+	    SYS_RES_MEMORY, &lesc->sc_brid, RF_ACTIVE);
+	if (lesc->sc_bres == NULL) {
+		device_printf(dev, "cannot allocate LANCE buffer\n");
+		error = ENXIO;
+		goto fail_mtx;
+	}
+	lesc->sc_buft = rman_get_bustag(lesc->sc_bres);
+	lesc->sc_bufh = rman_get_bushandle(lesc->sc_bres);
+
+	/* Allocate LANCE registers. */
+	lesc->sc_rrid = 0;
+	lesc->sc_rres = bus_alloc_resource_any(dev, SYS_RES_MEMORY,
+	    &lesc->sc_rrid, RF_ACTIVE);
+	if (lesc->sc_rres == NULL) {
+		device_printf(dev, "cannot allocate LANCE registers\n");
+		error = ENXIO;
+		goto fail_bres;
+	}
+	lesc->sc_regt = rman_get_bustag(lesc->sc_rres);
+	lesc->sc_regh = rman_get_bushandle(lesc->sc_rres);
+
+	/* Allocate LANCE interrupt. */
+	lesc->sc_irid = 0;
+	if ((lesc->sc_ires = bus_alloc_resource_any(dev, SYS_RES_IRQ,
+	    &lesc->sc_irid, RF_SHAREABLE | RF_ACTIVE)) == NULL) {
+		device_printf(dev, "cannot allocate interrupt\n");
+		error = ENXIO;
+		goto fail_rres;
+	}
+
+	/*
+	 * LANCE view is offset by buffer location.
+	 * Note that we don't use sc->sc_mem.
+	 */
+	sc->sc_addr = 0;
+	sc->sc_memsize = rman_get_size(lesc->sc_bres);
+	sc->sc_flags = 0;
+
+	/* That old black magic... */
+	if (OF_getprop(ofw_bus_get_node(dev), "busmaster-regval",
+	    &sc->sc_conf3, sizeof(sc->sc_conf3)) == -1)
+		sc->sc_conf3 = LE_C3_ACON | LE_C3_BCON;
+	/*
+	 * Make sure LE_C3_BSWP is cleared so that for cards where
+	 * that flag actually works le_lebuffer_copy{from,to}buf()
+	 * don't fail...
+	 */
+	sc->sc_conf3 &= ~LE_C3_BSWP;
+
+	OF_getetheraddr(dev, sc->sc_enaddr);
+
+	sc->sc_copytodesc = le_lebuffer_copytodesc;
+	sc->sc_copyfromdesc = le_lebuffer_copyfromdesc;
+	sc->sc_copytobuf = le_lebuffer_copytobuf;
+	sc->sc_copyfrombuf = le_lebuffer_copyfrombuf;
+	sc->sc_zerobuf = le_lebuffer_zerobuf;
+
+	sc->sc_rdcsr = le_lebuffer_rdcsr;
+	sc->sc_wrcsr = le_lebuffer_wrcsr;
+	sc->sc_hwreset = NULL;
+	sc->sc_hwinit = NULL;
+	sc->sc_hwintr = NULL;
+	sc->sc_nocarrier = NULL;
+	sc->sc_mediachange = NULL;
+	sc->sc_mediastatus = NULL;
+	sc->sc_supmedia = le_lebuffer_media;
+	sc->sc_nsupmedia = NLEMEDIA;
+	sc->sc_defaultmedia = le_lebuffer_media[0];
+
+	error = am7990_config(&lesc->sc_am7990, device_get_name(dev),
+	    device_get_unit(dev));
+	if (error != 0) {
+		device_printf(dev, "cannot attach Am7990\n");
+		goto fail_ires;
+	}
+
+	error = bus_setup_intr(dev, lesc->sc_ires, INTR_TYPE_NET | INTR_MPSAFE,
+	    am7990_intr, sc, &lesc->sc_ih);
+	if (error != 0) {
+		device_printf(dev, "cannot set up interrupt\n");
+		goto fail_am7990;
+	}
+
+	return (0);
+
+ fail_am7990:
+	am7990_detach(&lesc->sc_am7990);
+ fail_ires:
+	bus_release_resource(dev, SYS_RES_IRQ, lesc->sc_irid, lesc->sc_ires);
+ fail_rres:
+	bus_release_resource(dev, SYS_RES_MEMORY, lesc->sc_rrid, lesc->sc_rres);
+ fail_bres:
+	bus_release_resource(device_get_parent(dev), SYS_RES_MEMORY,
+	    lesc->sc_brid, lesc->sc_bres);
+ fail_mtx:
+	LE_LOCK_DESTROY(sc);
+	return (error);
+}
+
+static int
+le_lebuffer_detach(device_t dev)
+{
+	struct le_lebuffer_softc *lesc;
+	struct lance_softc *sc;
+
+	lesc = device_get_softc(dev);
+	sc = &lesc->sc_am7990.lsc;
+
+	bus_teardown_intr(dev, lesc->sc_ires, lesc->sc_ih);
+	am7990_detach(&lesc->sc_am7990);
+	bus_release_resource(dev, SYS_RES_IRQ, lesc->sc_irid, lesc->sc_ires);
+	bus_release_resource(dev, SYS_RES_MEMORY, lesc->sc_rrid, lesc->sc_rres);
+	bus_release_resource(device_get_parent(dev), SYS_RES_MEMORY,
+	    lesc->sc_brid, lesc->sc_bres);
+	LE_LOCK_DESTROY(sc);
+
+	return (0);
+}
+
+static int
+le_buffer_suspend(device_t dev)
+{
+	struct le_lebuffer_softc *lesc;
+
+	lesc = device_get_softc(dev);
+
+	lance_suspend(&lesc->sc_am7990.lsc);
+
+	return (0);
+}
+
+static int
+le_buffer_resume(device_t dev)
+{
+	struct le_lebuffer_softc *lesc;
+
+	lesc = device_get_softc(dev);
+
+	lance_resume(&lesc->sc_am7990.lsc);
+
+	return (0);
+}
diff --git a/sys/dev/le/lebuffer_sbus.c b/sys/dev/le/lebuffer_sbus.c
new file mode 100644
index 0000000..71a19fa
--- /dev/null
+++ b/sys/dev/le/lebuffer_sbus.c
@@ -0,0 +1,300 @@
+/*-
+ * Copyright (c) 2006 Marius Strobl <marius@FreeBSD.org>
+ * 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 THE AUTHOR AND CONTRIBUTORS ``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 THE AUTHOR OR CONTRIBUTORS 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/systm.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/resource.h>
+#include <sys/rman.h>
+
+#include <dev/ofw/ofw_bus.h>
+#include <dev/ofw/ofw_bus_subr.h>
+#include <dev/ofw/openfirm.h>
+
+#include <machine/bus.h>
+#include <machine/bus_common.h>
+#include <machine/resource.h>
+
+#include <sparc64/sbus/ofw_sbus.h>
+#include <sparc64/sbus/sbusreg.h>
+#include <sparc64/sbus/sbusvar.h>
+
+struct lebuffer_devinfo {
+	struct ofw_bus_devinfo	ldi_obdinfo;
+	struct resource_list	ldi_rl;
+};
+
+static devclass_t lebuffer_devclass;
+
+static device_probe_t lebuffer_probe;
+static device_attach_t lebuffer_attach;
+static device_detach_t lebuffer_detach;
+static bus_print_child_t lebuffer_print_child;
+static bus_probe_nomatch_t lebuffer_probe_nomatch;
+static bus_get_resource_list_t lebuffer_get_resource_list;
+static ofw_bus_get_devinfo_t lebuffer_get_devinfo;
+
+static struct lebuffer_devinfo *lebuffer_setup_dinfo(device_t, phandle_t);
+static void lebuffer_destroy_dinfo(struct lebuffer_devinfo *);
+static int lebuffer_print_res(struct lebuffer_devinfo *);
+
+static device_method_t lebuffer_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_probe,		lebuffer_probe),
+	DEVMETHOD(device_attach,	lebuffer_attach),
+	DEVMETHOD(device_detach,	lebuffer_detach),
+	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
+	DEVMETHOD(device_suspend,	bus_generic_suspend),
+	DEVMETHOD(device_resume,	bus_generic_resume),
+
+	/* Bus interface */
+	DEVMETHOD(bus_print_child,	lebuffer_print_child),
+	DEVMETHOD(bus_probe_nomatch,	lebuffer_probe_nomatch),
+	DEVMETHOD(bus_setup_intr,	bus_generic_setup_intr),
+	DEVMETHOD(bus_teardown_intr,	bus_generic_teardown_intr),
+	DEVMETHOD(bus_alloc_resource,	bus_generic_rl_alloc_resource),
+	DEVMETHOD(bus_release_resource, bus_generic_rl_release_resource),
+	DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
+	DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
+	DEVMETHOD(bus_get_resource_list, lebuffer_get_resource_list),
+	DEVMETHOD(bus_get_resource,	bus_generic_rl_get_resource),
+
+	/* ofw_bus interface */
+	DEVMETHOD(ofw_bus_get_devinfo,	lebuffer_get_devinfo),
+	DEVMETHOD(ofw_bus_get_compat,	ofw_bus_gen_get_compat),
+	DEVMETHOD(ofw_bus_get_model,	ofw_bus_gen_get_model),
+	DEVMETHOD(ofw_bus_get_name,	ofw_bus_gen_get_name),
+	DEVMETHOD(ofw_bus_get_node,	ofw_bus_gen_get_node),
+	DEVMETHOD(ofw_bus_get_type,	ofw_bus_gen_get_type),
+
+	{ 0, 0 }
+};
+
+DEFINE_CLASS_0(lebuffer, lebuffer_driver, lebuffer_methods, 1);
+DRIVER_MODULE(lebuffer, sbus, lebuffer_driver, lebuffer_devclass, 0, 0);
+
+static int
+lebuffer_probe(device_t dev)
+{
+	const char *name;
+
+	name = ofw_bus_get_name(dev);
+	if (strcmp(name, "lebuffer") == 0) {
+		device_set_desc_copy(dev, name);
+		return (0);
+	}
+	return (ENXIO);
+}
+
+static int
+lebuffer_attach(device_t dev)
+{
+	struct lebuffer_devinfo *ldi;
+	device_t cdev;
+	phandle_t child;
+	int children;
+
+	children = 0;
+	for (child = OF_child(ofw_bus_get_node(dev)); child != 0;
+	    child = OF_peer(child)) {
+		if ((ldi = lebuffer_setup_dinfo(dev, child)) == NULL)
+			continue;
+		if (children != 0) {
+			device_printf(dev,
+			    "<%s>: only one child per buffer supported\n",
+			    ldi->ldi_obdinfo.obd_name);
+			lebuffer_destroy_dinfo(ldi);
+			continue;
+		}
+		if ((cdev = device_add_child(dev, NULL, -1)) == NULL) {
+			device_printf(dev, "<%s>: device_add_child failed\n",
+			    ldi->ldi_obdinfo.obd_name);
+			lebuffer_destroy_dinfo(ldi);
+			continue;
+		}
+		device_set_ivars(cdev, ldi);
+		children++;
+	}
+	return (bus_generic_attach(dev));
+}
+
+static int
+lebuffer_detach(device_t dev)
+{
+	device_t *children;
+	int i, nchildren;
+
+	bus_generic_detach(dev);
+	if (device_get_children(dev, &children, &nchildren) == 0) {
+		for (i = 0; i < nchildren; i++) {
+			lebuffer_destroy_dinfo(device_get_ivars(children[i]));
+			device_delete_child(dev, children[i]);
+		}
+		free(children, M_TEMP);
+	}
+	return (0);
+}
+
+static struct lebuffer_devinfo *
+lebuffer_setup_dinfo(device_t dev, phandle_t node)
+{
+	struct lebuffer_devinfo *ldi;
+	struct sbus_regs *reg;
+	uint32_t base, iv, *intr;
+	int i, nreg, nintr, slot, rslot;
+
+	ldi = malloc(sizeof(*ldi), M_DEVBUF, M_WAITOK | M_ZERO);
+	if (ofw_bus_gen_setup_devinfo(&ldi->ldi_obdinfo, node) != 0) {
+		free(ldi, M_DEVBUF);
+		return (NULL);
+	}
+	resource_list_init(&ldi->ldi_rl);
+	slot = -1;
+	nreg = OF_getprop_alloc(node, "reg", sizeof(*reg), (void **)&reg);
+	if (nreg == -1) {
+		device_printf(dev, "<%s>: incomplete\n",
+		    ldi->ldi_obdinfo.obd_name);
+		goto fail;
+	}
+	for (i = 0; i < nreg; i++) {
+		base = reg[i].sbr_offset;
+		if (SBUS_ABS(base)) {
+			rslot = SBUS_ABS_TO_SLOT(base);
+			base = SBUS_ABS_TO_OFFSET(base);
+		} else
+			rslot = reg[i].sbr_slot;
+		if (slot != -1 && slot != rslot) {
+			device_printf(dev, "<%s>: multiple slots\n",
+			    ldi->ldi_obdinfo.obd_name);
+			free(reg, M_OFWPROP);
+			goto fail;
+		}
+		slot = rslot;
+
+		resource_list_add(&ldi->ldi_rl, SYS_RES_MEMORY, i, base,
+		    base + reg[i].sbr_size, reg[i].sbr_size);
+	}
+	free(reg, M_OFWPROP);
+	if (slot != sbus_get_slot(dev)) {
+		device_printf(dev, "<%s>: parent and child slot do not match\n",
+		    ldi->ldi_obdinfo.obd_name);
+		goto fail;
+	}
+
+	/*
+	 * The `interrupts' property contains the SBus interrupt level.
+	 */
+	nintr = OF_getprop_alloc(node, "interrupts", sizeof(*intr),
+	    (void **)&intr);
+	if (nintr != -1) {
+		for (i = 0; i < nintr; i++) {
+			iv = intr[i];
+			/*
+			 * SBus card devices need the slot number encoded into
+			 * the vector as this is generally not done.
+			 */
+			if ((iv & INTMAP_OBIO_MASK) == 0)
+				iv |= slot << 3;
+			/* Set the IGN as appropriate. */
+			iv |= sbus_get_ign(dev) << INTMAP_IGN_SHIFT;
+			resource_list_add(&ldi->ldi_rl, SYS_RES_IRQ, i,
+			    iv, iv, 1);
+		}
+		free(intr, M_OFWPROP);
+	}
+	return (ldi);
+
+ fail:
+	lebuffer_destroy_dinfo(ldi);
+	return (NULL);
+}
+
+static void
+lebuffer_destroy_dinfo(struct lebuffer_devinfo *dinfo)
+{
+
+	resource_list_free(&dinfo->ldi_rl);
+	ofw_bus_gen_destroy_devinfo(&dinfo->ldi_obdinfo);
+	free(dinfo, M_DEVBUF);
+}
+
+static int
+lebuffer_print_child(device_t dev, device_t child)
+{
+	int rv;
+
+	rv = bus_print_child_header(dev, child);
+	rv += lebuffer_print_res(device_get_ivars(child));
+	rv += bus_print_child_footer(dev, child);
+	return (rv);
+}
+
+static void
+lebuffer_probe_nomatch(device_t dev, device_t child)
+{
+	const char *type;
+
+	device_printf(dev, "<%s>", ofw_bus_get_name(child));
+	lebuffer_print_res(device_get_ivars(child));
+	type = ofw_bus_get_type(child);
+	printf(" type %s (no driver attached)\n",
+	    type != NULL ? type : "unknown");
+}
+
+static struct resource_list *
+lebuffer_get_resource_list(device_t dev, device_t child)
+{
+	struct lebuffer_devinfo *ldi;
+
+	ldi = device_get_ivars(child);
+	return (&ldi->ldi_rl);
+}
+
+static const struct ofw_bus_devinfo *
+lebuffer_get_devinfo(device_t bus, device_t child)
+{
+	struct lebuffer_devinfo *ldi;
+
+	ldi = device_get_ivars(child);
+	return (&ldi->ldi_obdinfo);
+}
+
+static int
+lebuffer_print_res(struct lebuffer_devinfo *ldi)
+{
+	int rv;
+
+	rv = 0;
+	rv += resource_list_print_type(&ldi->ldi_rl, "mem", SYS_RES_MEMORY,
+	    "%#lx");
+	rv += resource_list_print_type(&ldi->ldi_rl, "irq", SYS_RES_IRQ, "%ld");
+	return (rv);
+}