Add gfrtc a driver for the real-time clock interface of Google's

Goldfish Android virtual hardware platform.  Used for the RTC on
qemu-system-riscv64 -M virt.

feedback and ok kettenis@

4 files changed, 128 insertions, 2 deletions

diff --git a/sys/arch/riscv64/conf/GENERIC b/sys/arch/riscv64/conf/GENERIC
index 2942c9cf31e..f8394e102bf 100644
--- a/sys/arch/riscv64/conf/GENERIC
+++ b/sys/arch/riscv64/conf/GENERIC
@@ -48,6 +48,7 @@ simplebus*	at mainbus0 early 1
 plic*		at simplebus? early 1
 
 syscon*		at fdt? early 1
+gfrtc*		at fdt?
 
 scsibus*        at scsi?
 sd*		at scsibus?
diff --git a/sys/arch/riscv64/conf/RAMDISK b/sys/arch/riscv64/conf/RAMDISK
index 9eb91bc90ef..8427beef0e2 100644
--- a/sys/arch/riscv64/conf/RAMDISK
+++ b/sys/arch/riscv64/conf/RAMDISK
@@ -1,4 +1,4 @@
-# $OpenBSD: RAMDISK,v 1.3 2021/04/23 13:03:41 jsg Exp $
+# $OpenBSD: RAMDISK,v 1.4 2021/04/24 05:14:45 jsg Exp $
 #
 # GENERIC machine description file
 #
@@ -67,6 +67,7 @@ simplebus*	at mainbus0 early 1
 plic*		at simplebus? early 1
 
 syscon*		at fdt? early 1
+gfrtc*		at fdt?
 
 scsibus*        at scsi?
 sd*		at scsibus?
diff --git a/sys/dev/fdt/files.fdt b/sys/dev/fdt/files.fdt
index 27578a555b4..88d3b3402dc 100644
--- a/sys/dev/fdt/files.fdt
+++ b/sys/dev/fdt/files.fdt
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.fdt,v 1.147 2021/04/07 17:12:22 kettenis Exp $
+#	$OpenBSD: files.fdt,v 1.148 2021/04/24 05:14:45 jsg Exp $
 #
 # Config file and device description for machine-independent FDT code.
 # Included by ports that need it.
@@ -156,6 +156,11 @@ device	exuart
 attach	exuart at fdt
 file	dev/fdt/exuart.c		exuart
 
+# Google Goldfish real-time clock
+device	gfrtc
+attach	gfrtc at fdt
+file	dev/fdt/gfrtc.c			gfrtc
+
 # ARM PrimeCell PL061 General Purpose Input/Output
 device	plgpio
 attach	plgpio at fdt
diff --git a/sys/dev/fdt/gfrtc.c b/sys/dev/fdt/gfrtc.c
new file mode 100644
index 00000000000..503767ea631
--- /dev/null
+++ b/sys/dev/fdt/gfrtc.c
@@ -0,0 +1,119 @@
+/*	$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");
+}