Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933857AbcKCXfm (ORCPT ); Thu, 3 Nov 2016 19:35:42 -0400 Received: from smtprelay2.synopsys.com ([198.182.60.111]:35441 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933423AbcKCXfh (ORCPT ); Thu, 3 Nov 2016 19:35:37 -0400 From: Vineet Gupta To: Daniel Lezcano CC: Noam Camus , , , , , Vineet Gupta , Subject: [PATCH v3 01/10] ARC: timer: rtc: implement read loop in "C" vs. inline asm Date: Thu, 3 Nov 2016 16:33:26 -0700 Message-ID: <1478216015-18931-2-git-send-email-vgupta@synopsys.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1478216015-18931-1-git-send-email-vgupta@synopsys.com> References: <1478216015-18931-1-git-send-email-vgupta@synopsys.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.10.161.44] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1409 Lines: 46 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 Acked-by: Daniel Lezcano Signed-off-by: Vineet Gupta --- 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..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; } -- 2.7.4