ofw: Add a ofw_firmware driver

Some SoCs have an external firmware doing power management, clock
and other stuffs. (Xilinx, ARM Juno etc ...)
The way it is represent in the DTB is usually having a 'firmware' node
under the root node and have some nodes under it with the correct
compatible strings.
The firmware node itself doesn't have any compatible strings.
This driver is simple subclassed from simplebus and attaches at
BUS_PASS_BUS + BUS_PASS_ORDER_MIDDLE so early drivers (like clock drivers)
can still have a change to attach early.

Reviewed by:	andrew
Sponsored by:	Beckhoff Automation GmbH & Co. KG
Differential Revision:	https://reviews.freebsd.org/D37612

sys/conf/files

@@ -2579,6 +2579,7 @@ dev/ofw/ofw_bus_if.m		optional fdt
 dev/ofw/ofw_bus_subr.c		optional fdt
 dev/ofw/ofw_cpu.c		optional fdt
 dev/ofw/ofw_fdt.c		optional fdt
+dev/ofw/ofw_firmware.c		optional fdt
 dev/ofw/ofw_if.m		optional fdt
 dev/ofw/ofw_graph.c		optional fdt
 dev/ofw/ofw_subr.c		optional fdt

sys/dev/ofw/ofw_firmware.c

@@ -0,0 +1,161 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2022 Beckhoff Automation GmbH & Co. KG
+ *
+ * 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>
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/malloc.h>
+#include <sys/bus.h>
+#include <sys/cpu.h>
+#include <machine/bus.h>
+
+#include <dev/fdt/simplebus.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofw_bus.h>
+#include <dev/ofw/ofw_bus_subr.h>
+
+struct ofw_firmware_softc {
+	struct simplebus_softc	sc;
+	device_t		dev;
+};
+
+static struct simplebus_devinfo *
+ofw_firmware_setup_dinfo(device_t dev, phandle_t node,
+    struct simplebus_devinfo *di)
+{
+	struct simplebus_softc *sc;
+	struct simplebus_devinfo *ndi;
+
+	sc = device_get_softc(dev);
+	if (di == NULL)
+		ndi = malloc(sizeof(*ndi), M_DEVBUF, M_WAITOK | M_ZERO);
+	else
+		ndi = di;
+	if (ofw_bus_gen_setup_devinfo(&ndi->obdinfo, node) != 0) {
+		if (di == NULL)
+			free(ndi, M_DEVBUF);
+		return (NULL);
+	}
+
+	/* reg resources is from the parent but interrupts is on the node itself */
+	resource_list_init(&ndi->rl);
+	ofw_bus_reg_to_rl(dev, OF_parent(node), sc->acells, sc->scells, &ndi->rl);
+	ofw_bus_intr_to_rl(dev, node, &ndi->rl, NULL);
+
+	return (ndi);
+}
+
+static device_t
+ofw_firmware_add_device(device_t dev, phandle_t node, u_int order,
+    const char *name, int unit, struct simplebus_devinfo *di)
+{
+	struct simplebus_devinfo *ndi;
+	device_t cdev;
+
+	if ((ndi = ofw_firmware_setup_dinfo(dev, node, di)) == NULL)
+		return (NULL);
+	cdev = device_add_child_ordered(dev, order, name, unit);
+	if (cdev == NULL) {
+		device_printf(dev, "<%s>: device_add_child failed\n",
+		    ndi->obdinfo.obd_name);
+		resource_list_free(&ndi->rl);
+		ofw_bus_gen_destroy_devinfo(&ndi->obdinfo);
+		if (di == NULL)
+			free(ndi, M_DEVBUF);
+		return (NULL);
+	}
+	device_set_ivars(cdev, ndi);
+
+	return(cdev);
+}
+
+static int
+ofw_firmware_probe(device_t dev)
+{
+	const char *name;
+
+	name = ofw_bus_get_name(dev);
+	if (name == NULL || strcmp(name, "firmware") != 0)
+		return (ENXIO);
+
+	device_set_desc(dev, "OFW Firmware Group");
+	return (0);
+}
+
+static int
+ofw_firmware_attach(device_t dev)
+{
+	struct ofw_firmware_softc *sc;
+	phandle_t node, child;
+	device_t cdev;
+
+	sc = device_get_softc(dev);
+	sc->dev = dev;
+	node = ofw_bus_get_node(dev);
+
+	if (OF_getencprop(node, "#address-cells", &sc->sc.acells,
+	    sizeof(sc->sc.acells)) == -1) {
+		if (OF_getencprop(OF_parent(node), "#address-cells", &sc->sc.acells,
+		    sizeof(sc->sc.acells)) == -1) {
+			sc->sc.acells = 2;
+		}
+	}
+	if (OF_getencprop(node, "#size-cells", &sc->sc.scells,
+	    sizeof(sc->sc.scells)) == -1) {
+		if (OF_getencprop(OF_parent(node), "#size-cells", &sc->sc.scells,
+		    sizeof(sc->sc.scells)) == -1) {
+			sc->sc.scells = 1;
+		}
+	}
+
+	for (child = OF_child(node); child != 0; child = OF_peer(child)) {
+		cdev = ofw_firmware_add_device(dev, child, 0, NULL, -1, NULL);
+		if (cdev != NULL)
+			device_probe_and_attach(cdev);
+	}
+
+	return (bus_generic_attach(dev));
+}
+
+static device_method_t ofw_firmware_methods[] = {
+	/* device_if */
+	DEVMETHOD(device_probe, 	ofw_firmware_probe),
+	DEVMETHOD(device_attach, 	ofw_firmware_attach),
+
+	DEVMETHOD_END
+};
+
+DEFINE_CLASS_1(ofw_firmware, ofw_firmware_driver, ofw_firmware_methods,
+  sizeof(struct ofw_firmware_softc), simplebus_driver);
+
+EARLY_DRIVER_MODULE(ofw_firmware, simplebus, ofw_firmware_driver, 0, 0,
+    BUS_PASS_BUS + BUS_PASS_ORDER_MIDDLE);
+MODULE_VERSION(ofw_firmware, 1);