--- /dev/null
+/* $OpenBSD: gfrtc.c,v 1.1 2021/04/24 05:14:45 jsg Exp $ */
+
+/*
+ * Copyright (c) 2021 Jonathan Gray <jsg@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.
+ */
+
+/*
+ * Google Goldfish virtual real-time clock described in
+ * https://android.googlesource.com/platform/external/qemu/+/master/docs/GOLDFISH-VIRTUAL-HARDWARE.TXT
+ */
+
+#include <sys/param.h>
+#include <sys/device.h>
+#include <sys/malloc.h>
+#include <sys/systm.h>
+
+#include <machine/bus.h>
+#include <machine/fdt.h>
+#include <dev/clock_subr.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/fdt.h>
+
+#define TIME_LOW 0x00
+#define TIME_HIGH 0x04
+#define ALARM_LOW 0x0c
+#define CLEAR_INTERRUPT 0x10
+
+extern todr_chip_handle_t todr_handle;
+
+struct gfrtc_softc {
+ struct device sc_dev;
+ bus_space_tag_t sc_iot;
+ bus_space_handle_t sc_ioh;
+ struct todr_chip_handle sc_todr;
+};
+
+int gfrtc_match(struct device *, void *, void *);
+void gfrtc_attach(struct device *, struct device *, void *);
+int gfrtc_gettime(struct todr_chip_handle *, struct timeval *);
+int gfrtc_settime(struct todr_chip_handle *, struct timeval *);
+
+struct cfattach gfrtc_ca = {
+ sizeof(struct gfrtc_softc), gfrtc_match, gfrtc_attach
+};
+
+struct cfdriver gfrtc_cd = {
+ NULL, "gfrtc", DV_DULL
+};
+
+int
+gfrtc_gettime(todr_chip_handle_t handle, struct timeval *tv)
+{
+ struct gfrtc_softc *sc = handle->cookie;
+ uint64_t tl, th;
+
+ tl = bus_space_read_4(sc->sc_iot, sc->sc_ioh, TIME_LOW);
+ th = bus_space_read_4(sc->sc_iot, sc->sc_ioh, TIME_HIGH);
+
+ NSEC_TO_TIMEVAL((th << 32) | tl, tv);
+
+ return 0;
+}
+
+int
+gfrtc_settime(todr_chip_handle_t handle, struct timeval *tv)
+{
+ struct gfrtc_softc *sc = handle->cookie;
+ uint64_t ns;
+
+ ns = TIMEVAL_TO_NSEC(tv);
+
+ bus_space_write_4(sc->sc_iot, sc->sc_ioh, TIME_HIGH, ns >> 32);
+ bus_space_write_4(sc->sc_iot, sc->sc_ioh, TIME_LOW, ns);
+
+ return 0;
+}
+
+int
+gfrtc_match(struct device *parent, void *match, void *aux)
+{
+ struct fdt_attach_args *faa = aux;
+
+ return OF_is_compatible(faa->fa_node, "google,goldfish-rtc");
+}
+
+void
+gfrtc_attach(struct device *parent, struct device *self, void *aux)
+{
+ struct fdt_attach_args *faa = aux;
+ struct gfrtc_softc *sc = (struct gfrtc_softc *) self;
+
+ 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(": failed to map mem space\n");
+ return;
+ }
+
+ sc->sc_todr.cookie = sc;
+ sc->sc_todr.todr_gettime = gfrtc_gettime;
+ sc->sc_todr.todr_settime = gfrtc_settime;
+ todr_handle = &sc->sc_todr;
+
+ printf("\n");
+}