From d63a631e72441687910b8ec4a9396ac5d05029fb Mon Sep 17 00:00:00 2001 From: Jessica Clarke Date: Sun, 26 Jul 2020 18:15:16 +0000 Subject: [PATCH] Add Goldfish RTC device driver for RISC-V This device was originally used as part of the goldfish virtual hardware platform used for emulating Android on QEMU, but is now also used as the RTC for the RISC-V virt machine in QEMU. It provides a simple 64-bit nanosecond timer exposed via a pair of memory-mapped 32-bit registers, although only with 1s granularity. Reviewed by: brooks (mentor), jhb (mentor), kp Approved by: brooks (mentor), jhb (mentor), kp Obtained from: CheriBSD Differential Revision: https://reviews.freebsd.org/D25717 --- sys/conf/files | 1 + sys/dev/goldfish/goldfish_rtc.c | 182 ++++++++++++++++++++++++++++++++ sys/riscv/conf/GENERIC | 2 + 3 files changed, 185 insertions(+) create mode 100644 sys/dev/goldfish/goldfish_rtc.c diff --git a/sys/conf/files b/sys/conf/files index da06f0250d3e..63f3eecaf0ad 100644 --- a/sys/conf/files +++ b/sys/conf/files @@ -1736,6 +1736,7 @@ dev/fxp/if_fxp.c optional fxp dev/fxp/inphy.c optional fxp dev/gem/if_gem.c optional gem dev/gem/if_gem_pci.c optional gem pci +dev/goldfish/goldfish_rtc.c optional goldfish_rtc fdt dev/gpio/dwgpio/dwgpio.c optional gpio dwgpio fdt dev/gpio/dwgpio/dwgpio_bus.c optional gpio dwgpio fdt dev/gpio/dwgpio/dwgpio_if.m optional gpio dwgpio fdt diff --git a/sys/dev/goldfish/goldfish_rtc.c b/sys/dev/goldfish/goldfish_rtc.c new file mode 100644 index 000000000000..d1c2b6627ae2 --- /dev/null +++ b/sys/dev/goldfish/goldfish_rtc.c @@ -0,0 +1,182 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * Copyright (c) 2020 Jessica Clarke + * + * 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. + */ + +/* + * RTC for the goldfish virtual hardware platform implemented in QEMU, + * initially for Android but now also used for RISC-V's virt machine. + * + * https://android.googlesource.com/platform/external/qemu/+/master/docs/GOLDFISH-VIRTUAL-HARDWARE.TXT + */ + +#include +__FBSDID("$FreeBSD$"); + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include +#include +#include + +#include "clock_if.h" + +#define GOLDFISH_RTC_TIME_LOW 0x00 +#define GOLDFISH_RTC_TIME_HIGH 0x04 + +struct goldfish_rtc_softc { + struct resource *res; + int rid; + struct mtx mtx; +}; + +static int +goldfish_rtc_probe(device_t dev) +{ + + if (!ofw_bus_status_okay(dev)) + return (ENXIO); + + if (ofw_bus_is_compatible(dev, "google,goldfish-rtc")) { + device_set_desc(dev, "Goldfish RTC"); + return (BUS_PROBE_DEFAULT); + } + + return (ENXIO); +} + +static int +goldfish_rtc_attach(device_t dev) +{ + struct goldfish_rtc_softc *sc; + + sc = device_get_softc(dev); + + sc->rid = 0; + sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &sc->rid, + RF_ACTIVE); + if (sc->res == NULL) { + device_printf(dev, "could not allocate resource\n"); + return (ENXIO); + } + + mtx_init(&sc->mtx, device_get_nameunit(dev), NULL, MTX_DEF); + + /* + * Register as a system realtime clock with 1 second resolution. + */ + clock_register_flags(dev, 1000000, CLOCKF_SETTIME_NO_ADJ); + clock_schedule(dev, 1); + + return (0); +} + +static int +goldfish_rtc_detach(device_t dev) +{ + struct goldfish_rtc_softc *sc; + + sc = device_get_softc(dev); + + clock_unregister(dev); + mtx_destroy(&sc->mtx); + bus_release_resource(dev, SYS_RES_MEMORY, sc->rid, sc->res); + + return (0); +} + +static int +goldfish_rtc_gettime(device_t dev, struct timespec *ts) +{ + struct goldfish_rtc_softc *sc; + uint64_t low, high, nsec; + + sc = device_get_softc(dev); + + /* + * Reading TIME_HIGH is defined in the documentation to give the high + * 32 bits corresponding to the last TIME_LOW read, so must be done in + * that order, but means we have atomicity guaranteed. + */ + mtx_lock(&sc->mtx); + low = bus_read_4(sc->res, GOLDFISH_RTC_TIME_LOW); + high = bus_read_4(sc->res, GOLDFISH_RTC_TIME_HIGH); + mtx_unlock(&sc->mtx); + + nsec = (high << 32) | low; + ts->tv_sec = nsec / 1000000000; + ts->tv_nsec = nsec % 1000000000; + + return (0); +} + +static int +goldfish_rtc_settime(device_t dev, struct timespec *ts) +{ + struct goldfish_rtc_softc *sc; + uint64_t nsec; + + sc = device_get_softc(dev); + + nsec = (uint64_t)ts->tv_sec * 1000000000 + ts->tv_nsec; + + mtx_lock(&sc->mtx); + bus_write_4(sc->res, GOLDFISH_RTC_TIME_HIGH, nsec >> 32); + bus_write_4(sc->res, GOLDFISH_RTC_TIME_LOW, nsec); + mtx_unlock(&sc->mtx); + + return (0); +} + +static device_method_t goldfish_rtc_methods[] = { + /* Device interface */ + DEVMETHOD(device_probe, goldfish_rtc_probe), + DEVMETHOD(device_attach, goldfish_rtc_attach), + DEVMETHOD(device_detach, goldfish_rtc_detach), + + /* Clock interface */ + DEVMETHOD(clock_gettime, goldfish_rtc_gettime), + DEVMETHOD(clock_settime, goldfish_rtc_settime), + + DEVMETHOD_END, +}; + +DEFINE_CLASS_0(goldfish_rtc, goldfish_rtc_driver, goldfish_rtc_methods, + sizeof(struct goldfish_rtc_softc)); +static devclass_t goldfish_rtc_devclass; + +DRIVER_MODULE(goldfish_rtc, simplebus, goldfish_rtc_driver, + goldfish_rtc_devclass, NULL, NULL); diff --git a/sys/riscv/conf/GENERIC b/sys/riscv/conf/GENERIC index 6086229b640c..2d26d28f8539 100644 --- a/sys/riscv/conf/GENERIC +++ b/sys/riscv/conf/GENERIC @@ -101,6 +101,8 @@ device uart # Generic UART driver device uart_lowrisc # lowRISC UART driver device uart_ns8250 # ns8250-type UART driver +# RTC +device goldfish_rtc # QEMU RTC # Ethernet drivers device miibus # MII bus support