From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D100C433E1 for ; Mon, 17 Aug 2020 12:56:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F04222078D for ; Mon, 17 Aug 2020 12:56:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597669013; bh=ERpMAdayk233Labrw+Lu7muZTEwuPknh19NdvGNHSMI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=ZVxy0yfssqvgKPBc8M3Pt1e3W4ofUbze+VeU4O/vHCxkW1FmloR59F1XSmPc5sBNi Rb1yahejuf/Ch4tr0GDoaVvn1szl1PBhoCFMNaDKYdc0YhtRwkfKk0bH9UhusdBzCm ZWW/q95sV4tZgLsRSnlO+PE9LOr4LxNkEQqfgDY0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728509AbgHQM4v (ORCPT ); Mon, 17 Aug 2020 08:56:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:47972 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726265AbgHQM4u (ORCPT ); Mon, 17 Aug 2020 08:56:50 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ADC552072E; Mon, 17 Aug 2020 12:56:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597669009; bh=ERpMAdayk233Labrw+Lu7muZTEwuPknh19NdvGNHSMI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=q5my1Mwo8/rP50v751943fs0FGAFtFae1A+Dz+biD7l+GcRGAiMRNkn8qGgI7zspP cEpukEBSMsw3z7ejoG8++F6AGY8JyrdeuevwPlIHFlvr6yP17ft7SPLeS6htKMEAqd XXVaERjnM8M8XvIYIw2P3xjXzpyt9obh8PR2A21U= Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1k7egy-003ZLe-9G; Mon, 17 Aug 2020 13:56:48 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 17 Aug 2020 13:56:48 +0100 From: Marc Zyngier To: Keqian Zhu Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Steven Price , Andrew Jones , Catalin Marinas , Will Deacon , James Morse , Suzuki K Poulose , wanghaibin.wang@huawei.com Subject: Re: [PATCH 2/2] clocksource: arm_arch_timer: Correct fault programming of CNTKCTL_EL1.EVNTI In-Reply-To: <20200817122415.6568-3-zhukeqian1@huawei.com> References: <20200817122415.6568-1-zhukeqian1@huawei.com> <20200817122415.6568-3-zhukeqian1@huawei.com> User-Agent: Roundcube Webmail/1.4.7 Message-ID: X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: zhukeqian1@huawei.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, steven.price@arm.com, drjones@redhat.com, catalin.marinas@arm.com, will@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, wanghaibin.wang@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-08-17 13:24, Keqian Zhu wrote: > ARM virtual counter supports event stream, it can only trigger an event > when the trigger bit (the value of CNTKCTL_EL1.EVNTI) of CNTVCT_EL0 > changes, > so the actual period of event stream is 2^(cntkctl_evnti + 1). For > example, > when the trigger bit is 0, then virtual counter trigger an event for > every > two cycles. > > Signed-off-by: Marc Zyngier I have never given you this tag, you are making it up. Please read Documentation/process/submitting-patches.rst to understand what tag you can put by yourself. At best, put "Suggested-by" tag, as this is different from what I posted anyway. Thanks, M. > Signed-off-by: Keqian Zhu > --- > drivers/clocksource/arm_arch_timer.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/clocksource/arm_arch_timer.c > b/drivers/clocksource/arm_arch_timer.c > index 6e11c60..4140a37 100644 > --- a/drivers/clocksource/arm_arch_timer.c > +++ b/drivers/clocksource/arm_arch_timer.c > @@ -794,10 +794,14 @@ static void arch_timer_configure_evtstream(void) > { > int evt_stream_div, pos; > > - /* Find the closest power of two to the divisor */ > - evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ; > + /* > + * Find the closest power of two to the divisor. As the event > + * stream can at most be generated at half the frequency of the > + * counter, use half the frequency when computing the divider. > + */ > + evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ / 2; > pos = fls(evt_stream_div); > - if (pos > 1 && !(evt_stream_div & (1 << (pos - 2)))) > + if ((pos == 1) || (pos > 1 && !(evt_stream_div & (1 << (pos - 2))))) > pos--; > /* enable event stream */ > arch_timer_evtstrm_enable(min(pos, 15)); -- Jazz is not dead. It just smells funny...