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ARC: timer: rtc: implement read loop in "C" vs. inline asm

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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.

CC: stable@vger.kernel.org	#4.2+
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta 2016-10-31 14:09:52 -07:00
parent e6e335bf3a
commit 922cc17199
1 changed files with 11 additions and 8 deletions
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19
arch/arc/kernel/time.c
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@ -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;
}