Add rkrng(4), a driver for the random number generator found on various

Rockchip SoCs.

ok kurt@

sys/arch/arm64/conf/GENERIC

@@ -1,4 +1,4 @@
-# $OpenBSD: GENERIC,v 1.148 2020/03/29 09:31:10 kettenis Exp $
+# $OpenBSD: GENERIC,v 1.149 2020/04/03 16:29:17 kettenis Exp $
 #
 # GENERIC machine description file
 #
@@ -205,6 +205,7 @@ iic*		at rkiic?
 rkpcie*		at fdt?
 pci*		at rkpcie?
 rkpwm*		at fdt?
+rkrng*		at fdt?
 rktemp*		at fdt?
 rkvop*		at fdt?
 rkdwusb*	at fdt?

sys/arch/arm64/conf/RAMDISK

@@ -1,4 +1,4 @@
-# $OpenBSD: RAMDISK,v 1.111 2020/03/20 09:25:42 patrick Exp $
+# $OpenBSD: RAMDISK,v 1.112 2020/04/03 16:29:17 kettenis Exp $
 #
 # GENERIC machine description file
 #
@@ -178,6 +178,7 @@ iic*		at rkiic?
 rkpcie*		at fdt?
 pci*		at rkpcie?
 rkpwm*		at fdt?
+rkrng*		at fdt?
 rkdwusb*	at fdt?
 dwmmc*		at fdt?
 sdmmc*		at dwmmc?

sys/dev/fdt/files.fdt

@@ -1,4 +1,4 @@
-#	$OpenBSD: files.fdt,v 1.116 2020/03/29 09:31:11 kettenis Exp $
+#	$OpenBSD: files.fdt,v 1.117 2020/04/03 16:29:17 kettenis Exp $
 #
 # Config file and device description for machine-independent FDT code.
 # Included by ports that need it.
@@ -278,6 +278,10 @@ device	rkpwm
 attach	rkpwm at fdt
 file	dev/fdt/rkpwm.c			rkpwm
 
+device	rkrng
+attach	rkrng at fdt
+file	dev/fdt/rkrng.c			rkrng
+
 device	rktemp
 attach	rktemp at fdt
 file	dev/fdt/rktemp.c		rktemp

sys/dev/fdt/rkrng.c

@@ -0,0 +1,124 @@
+/*	$OpenBSD: rkrng.c,v 1.1 2020/04/03 16:29:17 kettenis Exp $	*/
+/*
+ * Copyright (c) 2020 Mark Kettenis <kettenis@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/rndvar.h>
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/fdt.h>
+
+/* Registers */
+#define RNG_CTRL			0x0008
+#define  RNG_CTRL_START			(1 << 8)
+#define RNG_TRNG_CTRL			0x0200
+#define  RNG_TRNG_CTRL_OSC_ENABLE	(1 << 16)
+#define  RNG_TRNG_CTRL_SAMPLE_PERIOD(x)	(x)
+#define RNG_DATA0			0x0204
+
+#define HREAD4(sc, reg)							\
+	(bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
+#define HWRITE4(sc, reg, val)						\
+	bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
+
+struct rkrng_softc {
+	struct device		sc_dev;
+	bus_space_tag_t		sc_iot;
+	bus_space_handle_t	sc_ioh;
+
+	struct timeout		sc_to;
+	int			sc_started;
+};
+
+int	rkrng_match(struct device *, void *, void *);
+void	rkrng_attach(struct device *, struct device *, void *);
+
+struct cfattach	rkrng_ca = {
+	sizeof (struct rkrng_softc), rkrng_match, rkrng_attach
+};
+
+struct cfdriver rkrng_cd = {
+	NULL, "rkrng", DV_DULL
+};
+
+void	rkrng_rnd(void *);
+
+int
+rkrng_match(struct device *parent, void *match, void *aux)
+{
+	struct fdt_attach_args *faa = aux;
+
+	return OF_is_compatible(faa->fa_node, "rockchip,cryptov1-rng");
+}
+
+void
+rkrng_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct rkrng_softc *sc = (struct rkrng_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;
+	}
+
+	printf("\n");
+
+	timeout_set(&sc->sc_to, rkrng_rnd, sc);
+	rkrng_rnd(sc);
+}
+
+void
+rkrng_rnd(void *arg)
+{
+	struct rkrng_softc *sc = arg;
+	bus_size_t off;
+
+	if (!sc->sc_started) {
+		HWRITE4(sc, RNG_TRNG_CTRL, RNG_TRNG_CTRL_OSC_ENABLE |
+		    RNG_TRNG_CTRL_SAMPLE_PERIOD(100));
+		HWRITE4(sc, RNG_CTRL, (RNG_CTRL_START << 16) | RNG_CTRL_START);
+		sc->sc_started = 1;
+		timeout_add_usec(&sc->sc_to, 100);
+		return;
+	}
+
+	if (HREAD4(sc, RNG_CTRL) & RNG_CTRL_START) {
+		timeout_add_usec(&sc->sc_to, 100);
+		return;
+	}
+
+	for (off = 0; off < 32; off += 4)
+		enqueue_randomness(HREAD4(sc, RNG_DATA0 + off));
+
+	HWRITE4(sc, RNG_CTRL, (RNG_CTRL_START << 16) | 0);
+	sc->sc_started = 0;
+
+	timeout_add_sec(&sc->sc_to, 1);
+}