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Add reset capability to mv_rtc driver

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This commit enables optional reset of the RTC, in case
its registers' contents did not sustain the reboot or power-off/on
sequence. Without it, further usage of RTC is impossible
(e.g. writing values to RTC_TIME register will not succeed).

The reset is performed only if Clock Correction register
does not comprise RTC_NOMINAL_TIMING, what helps to distinguish,
whether the software configured RTC before or it comprises
the default value.

Submitted by: Bartosz Szczepanek <bsz@semihalf.com>
Obtained from: Semihalf
Sponsored by: Stormshield
Differential revision: https://reviews.freebsd.org/D10900
This commit is contained in:
Zbigniew Bodek 2017-06-08 16:46:38 +00:00
parent 4bd7e351f1
commit 054beaac09
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=319703
1 changed files with 55 additions and 0 deletions
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55
sys/arm/mv/armada38x/rtc.c
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@ -56,6 +56,18 @@ __FBSDID("$FreeBSD$");
#define RTC_STATUS 0x0
#define RTC_TIME 0xC
#define RTC_TEST_CONFIG 0x1C
#define RTC_IRQ_1_CONFIG 0x4
#define RTC_IRQ_2_CONFIG 0x8
#define RTC_ALARM_1 0x10
#define RTC_ALARM_2 0x14
#define RTC_CLOCK_CORR 0x18
#define RTC_NOMINAL_TIMING 0x2000
#define RTC_NOMINAL_TIMING_MASK 0x7fff
#define RTC_STATUS_ALARM1_MASK 0x1
#define RTC_STATUS_ALARM2_MASK 0x2
#define MV_RTC_LOCK(sc) mtx_lock(&(sc)->mutex)
#define MV_RTC_UNLOCK(sc) mtx_unlock(&(sc)->mutex)
@ -103,6 +115,43 @@ static devclass_t mv_rtc_devclass;
DRIVER_MODULE(mv_rtc, simplebus, mv_rtc_driver, mv_rtc_devclass, 0, 0);
static void
mv_rtc_reset(device_t dev)
{
struct mv_rtc_softc *sc;
sc = device_get_softc(dev);
/* Reset Test register */
mv_rtc_reg_write(sc, RTC_TEST_CONFIG, 0);
DELAY(500000);
/* Reset Time register */
mv_rtc_reg_write(sc, RTC_TIME, 0);
DELAY(62);
/* Reset Status register */
mv_rtc_reg_write(sc, RTC_STATUS, (RTC_STATUS_ALARM1_MASK | RTC_STATUS_ALARM2_MASK));
DELAY(62);
/* Turn off Int1 and Int2 sources & clear the Alarm count */
mv_rtc_reg_write(sc, RTC_IRQ_1_CONFIG, 0);
mv_rtc_reg_write(sc, RTC_IRQ_2_CONFIG, 0);
mv_rtc_reg_write(sc, RTC_ALARM_1, 0);
mv_rtc_reg_write(sc, RTC_ALARM_2, 0);
/* Setup nominal register access timing */
mv_rtc_reg_write(sc, RTC_CLOCK_CORR, RTC_NOMINAL_TIMING);
/* Reset Time register */
mv_rtc_reg_write(sc, RTC_TIME, 0);
DELAY(10);
/* Reset Status register */
mv_rtc_reg_write(sc, RTC_STATUS, (RTC_STATUS_ALARM1_MASK | RTC_STATUS_ALARM2_MASK));
DELAY(50);
}
static int
mv_rtc_probe(device_t dev)
{
@ -198,6 +247,12 @@ mv_rtc_settime(device_t dev, struct timespec *ts)
MV_RTC_LOCK(sc);
if ((mv_rtc_reg_read(sc, RTC_CLOCK_CORR) & RTC_NOMINAL_TIMING_MASK) !=
RTC_NOMINAL_TIMING) {
/* RTC was not resetted yet */
mv_rtc_reset(dev);
}
/*
* According to errata FE-3124064, Write to RTC TIME register
* may fail. As a workaround, before writing to RTC TIME register,