diff options
| author | Vineet Gupta <vgupta@synopsys.com> | 2016-10-31 14:09:52 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-11-18 10:51:45 +0100 |
| commit | 7fac0361f94e24b179c5a7d1cfc57790f33624b8 (patch) | |
| tree | 7abe4e89cd03b171762bec184c0c77986a2e240a /arch | |
| parent | 4058116db4d0afb9b03d90869ae7063c589ada34 (diff) | |
| download | lwn-7fac0361f94e24b179c5a7d1cfc57790f33624b8.tar.gz lwn-7fac0361f94e24b179c5a7d1cfc57790f33624b8.zip | |
ARC: timer: rtc: implement read loop in "C" vs. inline asm
commit 922cc171998ac3dbe74d57011ef7ed57e9b0d7df upstream.
The current code doesn't even compile as somehow the inline assembly
can't see the register names defined as ARC_RTC_*
I'm pretty sure It worked when I first got it merged, but the tools were
definitely different then.
So better to write this in "C" anyways.
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arc/kernel/time.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c index f927b8dc6edd..c10390d1ddb6 100644 --- a/arch/arc/kernel/time.c +++ b/arch/arc/kernel/time.c @@ -152,14 +152,17 @@ static cycle_t arc_read_rtc(struct clocksource *cs) cycle_t full; } stamp; - - __asm__ __volatile( - "1: \n" - " lr %0, [AUX_RTC_LOW] \n" - " lr %1, [AUX_RTC_HIGH] \n" - " lr %2, [AUX_RTC_CTRL] \n" - " bbit0.nt %2, 31, 1b \n" - : "=r" (stamp.low), "=r" (stamp.high), "=r" (status)); + /* + * hardware has an internal state machine which tracks readout of + * low/high and updates the CTRL.status if + * - interrupt/exception taken between the two reads + * - high increments after low has been read + */ + do { + stamp.low = read_aux_reg(AUX_RTC_LOW); + stamp.high = read_aux_reg(AUX_RTC_HIGH); + status = read_aux_reg(AUX_RTC_CTRL); + } while (!(status & _BITUL(31))); return stamp.full; } |