Add support for the 32-bit random number generator on MediaTek SoCs.

ok?

Index: sys/dev/fdt/mtrng.c
===================================================================
RCS file: sys/dev/fdt/mtrng.c
diff -N sys/dev/fdt/mtrng.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ sys/dev/fdt/mtrng.c	11 Feb 2025 06:08:45 -0000
@@ -0,0 +1,105 @@
+/*	$OpenBSD$	*/
+/*
+ * Copyright (c) 2025 James Hastings <hastings@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/timeout.h>
+
+#include <machine/bus.h>
+#include <machine/fdt.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofw_clock.h>
+#include <dev/ofw/fdt.h>
+
+/* Registers */
+#define RNG_CONF		0x00
+#define  RNG_READY		(1U << 31)
+#define  RNG_EN			(1U <<  0)
+#define RNG_DATA		0x08
+
+struct mtrng_softc {
+	struct device		sc_dev;
+	bus_space_tag_t		sc_iot;
+	bus_space_handle_t	sc_ioh;
+
+	struct timeout		sc_to;
+};
+
+int	mtrng_match(struct device *, void *, void *);
+void	mtrng_attach(struct device *, struct device *, void *);
+
+const struct cfattach	mtrng_ca = {
+	sizeof (struct mtrng_softc), mtrng_match, mtrng_attach
+};
+
+struct cfdriver mtrng_cd = {
+	NULL, "mtrng", DV_DULL
+};
+
+void	mtrng_rnd(void *);
+
+int
+mtrng_match(struct device *parent, void *match, void *aux)
+{
+	struct fdt_attach_args *faa = aux;
+
+	return OF_is_compatible(faa->fa_node, "mediatek,mt7623-rng");
+}
+
+void
+mtrng_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct mtrng_softc *sc = (struct mtrng_softc *)self;
+	struct fdt_attach_args *faa = aux;
+
+	if (faa->fa_nreg < 1) {
+		printf(": no registers\n");
+		return;
+	}
+
+	sc->sc_iot = faa->fa_iot;
+	if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
+	    faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
+		printf(": can't map registers\n");
+		return;
+	}
+
+	clock_enable_all(faa->fa_node);
+
+	bus_space_write_4(sc->sc_iot, sc->sc_ioh, RNG_CONF, RNG_EN);
+
+	printf("\n");
+
+	timeout_set(&sc->sc_to, mtrng_rnd, sc);
+	mtrng_rnd(sc);
+}
+
+void
+mtrng_rnd(void *arg)
+{
+	struct mtrng_softc *sc = arg;
+	uint32_t sta;
+
+	sta = bus_space_read_4(sc->sc_iot, sc->sc_ioh, RNG_CONF);
+	if ((sta & RNG_READY) == RNG_READY)
+		enqueue_randomness(bus_space_read_4(sc->sc_iot,
+		    sc->sc_ioh, RNG_DATA));
+
+	timeout_add_sec(&sc->sc_to, 1);
+}
Index: sys/dev/fdt/files.fdt
===================================================================
RCS file: /cvs/src/sys/dev/fdt/files.fdt,v
retrieving revision 1.205
diff -u -p -r1.205 files.fdt
--- sys/dev/fdt/files.fdt	30 Jan 2025 00:26:44 -0000	1.205
+++ sys/dev/fdt/files.fdt	11 Feb 2025 06:08:45 -0000
@@ -340,6 +340,10 @@ device	mtintc
 attach	mtintc at fdt
 file	dev/fdt/mtintc.c		mtintc
 
+device	mtrng
+attach	mtrng at fdt
+file	dev/fdt/mtrng.c			mtrng
+
 device	rkanxdp
 attach	rkanxdp at fdt
 file	dev/fdt/rkanxdp.c		rkanxdp
Index: share/man/man4/mtrng.4
===================================================================
RCS file: share/man/man4/mtrng.4
diff -N share/man/man4/mtrng.4
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ share/man/man4/mtrng.4	11 Feb 2025 06:08:45 -0000
@@ -0,0 +1,47 @@
+.\"	$OpenBSD$
+.\"
+.\" Copyright (c) 2025 James Hastings <hastings@openbsd.org>
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.Dd $Mdocdate$
+.Dt MTRNG 4
+.Os
+.Sh NAME
+.Nm mtrng
+.Nd MediaTek random number generator
+.Sh SYNOPSIS
+.Cd "mtrng* at fdt?"
+.Sh DESCRIPTION
+The
+.Nm
+driver provides support for the random number generator found on
+MediaTek SoCs.
+.Pp
+It feeds the random subsystem's entropy pool with 32 bits of
+random data every second.
+.Sh SEE ALSO
+.Xr intro 4 ,
+.Xr random 4 ,
+.Xr arc4random 9
+.Sh HISTORY
+The
+.Nm
+driver first appeared in
+.Ox 7.7 .
+.Sh AUTHORS
+.An -nosplit
+The
+.Nm
+driver was written by
+.An James Hastings Aq Mt hastings@openbsd.org .
Index: share/man/man4/Makefile
===================================================================
RCS file: /cvs/src/share/man/man4/Makefile,v
retrieving revision 1.858
diff -u -p -r1.858 Makefile
--- share/man/man4/Makefile	30 Jan 2025 00:31:55 -0000	1.858
+++ share/man/man4/Makefile	11 Feb 2025 06:08:45 -0000
@@ -59,7 +59,7 @@ MAN=	aac.4 abcrtc.4 abl.4 ac97.4 acphy.4
 	mcprtc.4 mcx.4 midi.4 mii.4 mfi.4 mfii.4 mfokrtc.4 \
 	mlphy.4 moscom.4 mos.4 mpe.4 mpath.4 mpi.4 mpii.4 \
 	mpip.4 mpu.4 msk.4 mpw.4 msts.4 mtd.4 mtdphy.4 \
-	mtintc.4 mtio.4 mtw.4 mue.4 \
+	mtintc.4 mtio.4 mtrng.4 mtw.4 mue.4 \
 	multicast.4 mvclock.4 mvdog.4 mvgicp.4 mvgpio.4 mvicu.4 mviic.4 \
 	mvkpcie.4 mvneta.4 mvpinctrl.4 mvpp.4 mvrng.4 mvrtc.4 mvspi.4 \
 	mvtemp.4 mvsw.4 mvuart.4 myx.4 \
Index: sys/arch/arm64/conf/GENERIC
===================================================================
RCS file: /cvs/src/sys/arch/arm64/conf/GENERIC,v
retrieving revision 1.291
diff -u -p -r1.291 GENERIC
--- sys/arch/arm64/conf/GENERIC	30 Jan 2025 07:32:04 -0000	1.291
+++ sys/arch/arm64/conf/GENERIC	11 Feb 2025 06:08:46 -0000
@@ -274,6 +274,7 @@ hitemp*		at fdt?
 
 # MediaTek SoCs
 mtintc*		at fdt?
+mtrng*		at fdt?
 
 # Marvell SoCs
 mvclock*	at fdt? early 1
Index: sys/arch/arm64/conf/RAMDISK
===================================================================
RCS file: /cvs/src/sys/arch/arm64/conf/RAMDISK,v
retrieving revision 1.220
diff -u -p -r1.220 RAMDISK
--- sys/arch/arm64/conf/RAMDISK	30 Jan 2025 07:32:04 -0000	1.220
+++ sys/arch/arm64/conf/RAMDISK	11 Feb 2025 06:08:46 -0000
@@ -206,6 +206,7 @@ hireset*	at fdt? early 1
 
 # MediaTek SoCs
 mtintc*		at fdt?
+mtrng*		at fdt?
 
 # Marvell SoCs
 mvclock*	at fdt? early 1
Index: sys/arch/armv7/conf/GENERIC
===================================================================
RCS file: /cvs/src/sys/arch/armv7/conf/GENERIC,v
retrieving revision 1.143
diff -u -p -r1.143 GENERIC
--- sys/arch/armv7/conf/GENERIC	30 Jan 2025 07:32:17 -0000	1.143
+++ sys/arch/armv7/conf/GENERIC	11 Feb 2025 06:08:46 -0000
@@ -186,6 +186,7 @@ usb*		at dwctwo?
 
 # MediaTek SoCs
 mtintc*		at fdt?
+mtrng*		at fdt?
 
 # Marvell SoC
 mvacc*		at fdt? early 1
Index: sys/arch/armv7/conf/RAMDISK
===================================================================
RCS file: /cvs/src/sys/arch/armv7/conf/RAMDISK,v
retrieving revision 1.131
diff -u -p -r1.131 RAMDISK
--- sys/arch/armv7/conf/RAMDISK	30 Jan 2025 07:32:17 -0000	1.131
+++ sys/arch/armv7/conf/RAMDISK	11 Feb 2025 06:08:46 -0000
@@ -172,6 +172,7 @@ usb*		at dwctwo?
 
 # MediaTek SoCs
 mtintc*		at fdt?
+mtrng*		at fdt?
 
 # Marvell SoC
 mvacc*		at fdt? early 1