freebsd-dev/sys/mips/ingenic/jz4780_rtc.c
Alexander Kabaev 72565e644e Add driver for JZ4780 RTC device.
Only support basic timekeeping for now.
2016-12-24 02:31:26 +00:00

235 lines
5.6 KiB
C

/*-
* Copyright 2016 Alexander Kabaev <kan@FreeBSD.org>
* All rights reserved.
*
* 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.
*/
/*
* Ingenic JZ4780 RTC driver
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/clock.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/resource.h>
#include <machine/bus.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include "clock_if.h"
#define JZ_RTC_TIMEOUT 5000
#define JZ_RTCCR 0x00
# define JZ_RTCCR_WRDY (1u << 7)
#define JZ_RTSR 0x04
#define JZ_HSPR 0x34
#define JZ_WENR 0x3C
# define JZ_WENR_PAT 0xa55a
# define JZ_WENR_WEN (1u <<31)
struct jz4780_rtc_softc {
device_t dev;
struct resource *res[2];
};
static struct resource_spec jz4780_rtc_spec[] = {
{ SYS_RES_MEMORY, 0, RF_ACTIVE },
{ SYS_RES_IRQ, 0, RF_ACTIVE },
{ -1, 0 }
};
#define CSR_READ(sc, reg) bus_read_4((sc)->res[0], (reg))
#define CSR_WRITE(sc, reg, val) bus_write_4((sc)->res[0], (reg), (val))
static int jz4780_rtc_probe(device_t dev);
static int jz4780_rtc_attach(device_t dev);
static int jz4780_rtc_detach(device_t dev);
static int
jz4780_rtc_probe(device_t dev)
{
if (!ofw_bus_status_okay(dev))
return (ENXIO);
if (!ofw_bus_is_compatible(dev, "ingenic,jz4780-rtc"))
return (ENXIO);
device_set_desc(dev, "JZ4780 RTC");
return (BUS_PROBE_DEFAULT);
}
/* Poll control register until RTC is ready to accept register writes */
static int
jz4780_rtc_wait(struct jz4780_rtc_softc *sc)
{
int timeout;
timeout = JZ_RTC_TIMEOUT;
while (timeout-- > 0) {
if (CSR_READ(sc, JZ_RTCCR) & JZ_RTCCR_WRDY)
return (0);
}
return (EIO);
}
/*
* Write RTC register. It appears that RTC goes into read-only mode at random,
* which suggests something is up with how it is powered up, so do the pattern
* writing dance every time just in case.
*/
static int
jz4780_rtc_write(struct jz4780_rtc_softc *sc, uint32_t reg, uint32_t val)
{
int ret, timeout;
ret = jz4780_rtc_wait(sc);
if (ret != 0)
return (ret);
CSR_WRITE(sc, JZ_WENR, JZ_WENR_PAT);
ret = jz4780_rtc_wait(sc);
if (ret)
return ret;
timeout = JZ_RTC_TIMEOUT;
while (timeout-- > 0) {
if (CSR_READ(sc, JZ_WENR) & JZ_WENR_WEN)
break;
}
if (timeout < 0)
return (EIO);
CSR_WRITE(sc, reg, val);
return 0;
}
static int
jz4780_rtc_attach(device_t dev)
{
struct jz4780_rtc_softc *sc = device_get_softc(dev);
uint32_t scratch;
int ret;
sc->dev = dev;
if (bus_alloc_resources(dev, jz4780_rtc_spec, sc->res)) {
device_printf(dev, "could not allocate resources for device\n");
return (ENXIO);
}
scratch = CSR_READ(sc, JZ_HSPR);
if (scratch != 0x12345678) {
ret = jz4780_rtc_write(sc, JZ_HSPR, 0x12345678);
if (ret == 0)
ret = jz4780_rtc_write(sc, JZ_RTSR, 0);
if (ret) {
device_printf(dev, "Unable to write RTC registers\n");
jz4780_rtc_detach(dev);
return (ret);
}
}
clock_register(dev, 1000000); /* Register 1 HZ clock */
return (0);
}
static int
jz4780_rtc_detach(device_t dev)
{
struct jz4780_rtc_softc *sc;
sc = device_get_softc(dev);
bus_release_resources(dev, jz4780_rtc_spec, sc->res);
return (0);
}
static int
jz4780_rtc_gettime(device_t dev, struct timespec *ts)
{
struct jz4780_rtc_softc *sc;
uint32_t val1, val2;
int timeout;
sc = device_get_softc(dev);
timeout = JZ_RTC_TIMEOUT;
val2 = CSR_READ(sc, JZ_RTSR);
do {
val1 = val2;
val2 = CSR_READ(sc, JZ_RTSR);
} while (val1 != val2 && timeout-- >= 0);
if (timeout < 0)
return (EIO);
/* Convert secs to timespec directly */
ts->tv_sec = val1;
ts->tv_nsec = 0;
return 0;
}
static int
jz4780_rtc_settime(device_t dev, struct timespec *ts)
{
struct jz4780_rtc_softc *sc;
sc = device_get_softc(dev);
return jz4780_rtc_write(sc, JZ_RTSR, ts->tv_sec);
}
static device_method_t jz4780_rtc_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, jz4780_rtc_probe),
DEVMETHOD(device_attach, jz4780_rtc_attach),
DEVMETHOD(device_detach, jz4780_rtc_detach),
DEVMETHOD(clock_gettime, jz4780_rtc_gettime),
DEVMETHOD(clock_settime, jz4780_rtc_settime),
DEVMETHOD_END
};
static driver_t jz4780_rtc_driver = {
"jz4780_rtc",
jz4780_rtc_methods,
sizeof(struct jz4780_rtc_softc),
};
static devclass_t jz4780_rtc_devclass;
EARLY_DRIVER_MODULE(jz4780_rtc, simplebus, jz4780_rtc_driver,
jz4780_rtc_devclass, 0, 0, BUS_PASS_TIMER + BUS_PASS_ORDER_MIDDLE);