From c45bfaa9211ef5936916503bdba639eae3761777 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Mon, 31 Oct 2016 14:09:52 -0700 Subject: 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 Signed-off-by: Vineet Gupta Signed-off-by: Greg Kroah-Hartman --- arch/arc/kernel/time.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'arch') diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c index dfad287f1db1..dbedc576e4ca 100644 --- a/arch/arc/kernel/time.c +++ b/arch/arc/kernel/time.c @@ -130,14 +130,17 @@ static cycle_t arc_counter_read(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; } -- cgit v1.2.3