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| author | Ingo Molnar <mingo@kernel.org> | 2021-02-17 14:04:39 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2021-02-17 14:04:39 +0100 |
| commit | ed3cd45f8ca873dd320ff7e6b4c1c8f83a65302c (patch) | |
| tree | 783a02c1e78964654fe6d9a9c14b24bfc50e6b3b /drivers/rtc/rtc-mc146818-lib.c | |
| parent | bae4ec13640b0915e7dd86da7e65c5d085160571 (diff) | |
| parent | f40ddce88593482919761f74910f42f4b84c004b (diff) | |
Merge tag 'v5.11' into sched/core, to pick up fixes & refresh the branch
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/rtc/rtc-mc146818-lib.c')
| -rw-r--r-- | drivers/rtc/rtc-mc146818-lib.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c index 972a5b9a629d..dcfaf09946ee 100644 --- a/drivers/rtc/rtc-mc146818-lib.c +++ b/drivers/rtc/rtc-mc146818-lib.c @@ -21,6 +21,13 @@ unsigned int mc146818_get_time(struct rtc_time *time) again: spin_lock_irqsave(&rtc_lock, flags); + /* Ensure that the RTC is accessible. Bit 6 must be 0! */ + if (WARN_ON_ONCE((CMOS_READ(RTC_VALID) & 0x40) != 0)) { + spin_unlock_irqrestore(&rtc_lock, flags); + memset(time, 0xff, sizeof(*time)); + return 0; + } + /* * Check whether there is an update in progress during which the * readout is unspecified. The maximum update time is ~2ms. Poll |