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[PATCH v2 01/10] ARC: timer: rtc: implement read loop in "C" vs. inline asm

From Vineet Gupta <Vineet.Gupta1@synopsys.com>
Newsgroups linux.kernel
Subject [PATCH v2 01/10] ARC: timer: rtc: implement read loop in "C" vs. inline asm
Date 2016-11-03 22:40 +0100
Message-ID <szxTP-UG-9@gated-at.bofh.it> (permalink)
References <szxTP-UG-11@gated-at.bofh.it>
Organization linux.* mail to news gateway

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The current code doesn't even compile ....

CC: stable@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/kernel/time.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c
index f927b8dc6edd..1a117b999c0c 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;
 }
-- 
2.7.4

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Thread

[PATCH v2 00/10] Move ARC timer code into drivers/clocksource/ Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
  [PATCH v2 01/10] ARC: timer: rtc: implement read loop in "C" vs. inline asm Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
    Re: [PATCH v2 01/10] ARC: timer: rtc: implement read loop in "C" vs.  inline asm Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-11-03 23:00 +0100
      Re: [PATCH v2 01/10] ARC: timer: rtc: implement read loop in "C" vs.  inline asm Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 23:30 +0100
        Re: [PATCH v2 01/10] ARC: timer: rtc: implement read loop in "C" vs.  inline asm Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-11-03 23:40 +0100
          Re: [PATCH v2 01/10] ARC: timer: rtc: implement read loop in "C" vs.  inline asm Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-11-03 23:50 +0100
          Re: [PATCH v2 01/10] ARC: timer: rtc: implement read loop in "C" vs.  inline asm Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 23:50 +0100
    RE: [PATCH v2 01/10] ARC: timer: rtc: implement read loop in "C"  vs. inline asm Alexey Brodkin <Alexey.Brodkin@synopsys.com> - 2016-11-04 19:00 +0100
  [PATCH v2 05/10] ARC: time: move time_init() out of the driver Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
  [PATCH v2 07/10] ARC: breakout aux handling into a separate header Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
  [PATCH v2 08/10] ARC: move mcip.h into include/soc and adjust the includes Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
  [PATCH v2 02/10] ARC: timer: gfrc, rtc: deuglify big endian code Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
    Re: [PATCH v2 02/10] ARC: timer: gfrc, rtc: deuglify big endian code Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-11-03 23:00 +0100
      Re: [PATCH v2 02/10] ARC: timer: gfrc, rtc: deuglify big endian code Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 23:20 +0100
    RE: [PATCH v2 02/10] ARC: timer: gfrc, rtc: deuglify big endian code Alexey Brodkin <Alexey.Brodkin@synopsys.com> - 2016-11-04 19:20 +0100
  [PATCH v2 03/10] ARC: timer: gfrc, rtc: Read BCR to detect whether hardware exists ... Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
  [PATCH v2 10/10] clocksource: import ARC timer driver Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
    Re: [PATCH v2 10/10] clocksource: import ARC timer driver Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-11-03 23:40 +0100
      Re: [PATCH v2 10/10] clocksource: import ARC timer driver Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-04 00:00 +0100
        Re: [PATCH v2 10/10] clocksource: import ARC timer driver Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-04 00:10 +0100
        Re: [PATCH v2 10/10] clocksource: import ARC timer driver Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-11-04 00:10 +0100
  [PATCH v2 09/10] ARC: breakout timer include code into separate header ... Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
  [PATCH v2 04/10] ARC: timer: gfrc: boot print alongside other timers Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
  [PATCH v2 06/10] ARC: timer: Build gfrc, rtc under same option (64-bit timers) Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-11-03 22:40 +0100
    Re: [PATCH v2 06/10] ARC: timer: Build gfrc, rtc under same option  (64-bit timers) Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-11-03 23:20 +0100

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