Commit e1ef6c0e authored by Austin Zhang's avatar Austin Zhang Committed by Eric van Gyzen
Browse files

atrtc: reads Century field from FADT table

The ACPI spec describes the FADT->Century field as:

    The RTC CMOS RAM index to the century of data value (hundred and
    thousand year decimals).  If this field contains a zero, then the
    RTC centenary feature is not supported.  If this field has a non-zero
    value, then this field contains an index into RTC RAM space that
    OSPM can use to program the centenary field.

Use this field to decide whether to program the CENTURY register
of the CMOS RTC device.

Reviewed by:, dab, vangyzen
MFC after:	1 week
Sponsored by:	Dell EMC Isilon
Differential Revision:

MFC after:	1 week
Sponsored by:	Dell EMC Isilon
parent 900a7922
......@@ -79,6 +79,7 @@ MTX_SYSINIT(atrtc_time_lock_init, &atrtc_time_lock, "atrtc_time", MTX_DEF);
int atrtcclock_disable = 0;
static int rtc_century = 0;
static int rtc_reg = -1;
static u_char rtc_statusa = RTCSA_DIVIDER | RTCSA_NOPROF;
static u_char rtc_statusb = RTCSB_24HR;
......@@ -420,6 +421,31 @@ atrtc_acpi_disabled(void)
static int
#ifdef DEV_ACPI
vm_paddr_t physaddr;
int century;
physaddr = acpi_find_table(ACPI_SIG_FADT);
if (physaddr == 0)
return (0);
fadt = acpi_map_table(physaddr, ACPI_SIG_FADT);
if (fadt == NULL)
return (0);
century = fadt->Century;
return (century);
return (0);
static int
atrtc_probe(device_t dev)
......@@ -435,6 +461,7 @@ atrtc_probe(device_t dev)
device_set_desc(dev, "AT realtime clock");
rtc_century = rtc_acpi_century_get();
return (result);
......@@ -548,9 +575,8 @@ atrtc_settime(device_t dev __unused, struct timespec *ts)
rtcout_locked(RTC_MONTH, bct.mon);
rtcout_locked(RTC_YEAR, bct.year & 0xff);
rtcout_locked(RTC_CENTURY, bct.year >> 8);
if (rtc_century)
rtcout_locked(rtc_century, bct.year >> 8);
* Re-enable RTC updates and interrupts.
......@@ -592,9 +618,8 @@ atrtc_gettime(device_t dev, struct timespec *ts) = rtcin_locked(RTC_DAY);
bct.mon = rtcin_locked(RTC_MONTH);
bct.year = rtcin_locked(RTC_YEAR);
bct.year |= rtcin_locked(RTC_CENTURY) << 8;
if (rtc_century)
bct.year |= rtcin_locked(rtc_century) << 8;
/* dow is unused in timespec conversion and we have no nsec info. */
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