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aw_rtc: bump settime() delays

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There are delay loops, checking the BUSY status bit, before writing to
the date or time registers. Each iteration contains a 1usec delay, for a
maximum of 70 iterations.

This is frequently not enough on the D1 platform, where the message is
emitted:

  rtc0: could not set date, RTC busy

Bump the loop delay to 10usecs each, and the maximum number of
iterations to 150, for a maximum delay of 1.5msecs between each write of
the register.

In my testing this seems to be adequate.

The loop variable is renamed for clarity/simplicity.

Reviewed by:	manu
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D54180
This commit is contained in:
Mitchell Horne 2025-12-15 11:29:21 -04:00
parent b9b1262a8e
commit cae9ae66ad
1 changed files with 12 additions and 11 deletions
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23
sys/arm/allwinner/aw_rtc.c
View file

@ -87,7 +87,7 @@
#define HALF_OF_SEC_NS 500000000
#define RTC_RES_US 1000000
#define RTC_TIMEOUT 70
#define RTC_TIMEOUT 150
#define RTC_READ(sc, reg) bus_read_4((sc)->res, (reg))
#define RTC_WRITE(sc, reg, val) bus_write_4((sc)->res, (reg), (val))
@ -321,7 +321,8 @@ aw_rtc_settime(device_t dev, struct timespec *ts)
{
struct aw_rtc_softc *sc = device_get_softc(dev);
struct clocktime ct;
uint32_t clk, rdate, rtime;
uint32_t rdate, rtime;
u_int i;
/* RTC resolution is 1 sec */
if (ts->tv_nsec >= HALF_OF_SEC_NS)
@ -335,12 +336,12 @@ aw_rtc_settime(device_t dev, struct timespec *ts)
return (EINVAL);
}
for (clk = 0; RTC_READ(sc, LOSC_CTRL_REG) & LOSC_BUSY_MASK; clk++) {
if (clk > RTC_TIMEOUT) {
for (i = 0; RTC_READ(sc, LOSC_CTRL_REG) & LOSC_BUSY_MASK; i++) {
if (i > RTC_TIMEOUT) {
device_printf(dev, "could not set time, RTC busy\n");
return (EINVAL);
}
DELAY(1);
DELAY(10);
}
/* reset time register to avoid unexpected date increment */
RTC_WRITE(sc, sc->conf->rtc_time, 0);
@ -352,21 +353,21 @@ aw_rtc_settime(device_t dev, struct timespec *ts)
rtime = SET_SEC_VALUE(ct.sec) | SET_MIN_VALUE(ct.min) |
SET_HOUR_VALUE(ct.hour);
for (clk = 0; RTC_READ(sc, LOSC_CTRL_REG) & LOSC_BUSY_MASK; clk++) {
if (clk > RTC_TIMEOUT) {
for (i = 0; RTC_READ(sc, LOSC_CTRL_REG) & LOSC_BUSY_MASK; i++) {
if (i > RTC_TIMEOUT) {
device_printf(dev, "could not set date, RTC busy\n");
return (EINVAL);
}
DELAY(1);
DELAY(10);
}
RTC_WRITE(sc, sc->conf->rtc_date, rdate);
for (clk = 0; RTC_READ(sc, LOSC_CTRL_REG) & LOSC_BUSY_MASK; clk++) {
if (clk > RTC_TIMEOUT) {
for (i = 0; RTC_READ(sc, LOSC_CTRL_REG) & LOSC_BUSY_MASK; i++) {
if (i > RTC_TIMEOUT) {
device_printf(dev, "could not set time, RTC busy\n");
return (EINVAL);
}
DELAY(1);
DELAY(10);
}
RTC_WRITE(sc, sc->conf->rtc_time, rtime);