From patchwork Fri Dec 4 07:31:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: zhukeqian X-Patchwork-Id: 11950815 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=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 B0AB5C4361B for ; Fri, 4 Dec 2020 07:33:58 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5F54D22581 for ; Fri, 4 Dec 2020 07:33:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F54D22581 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-ID:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=j9VwYkoiDpehKYGsmzofDfiTCSd2CjcuFO8v3TbKp1c=; b=HkPnvfKzWgVCXWcmtOvCJjtUy P+MJgF7jKDngy3fQXClOhkZnGqcWUfkjo6tmwTVqEhl8m+otzpdxVC6F/MdB0JaE8y+NMm94pKP0x jCaBdRyyAJWrMwA6JQMiQDuDPee0Vis+7r8O+lPM72w/zOkCiV2QD+I9S+8VUBTw+Tbkh7HbfWmmK GfZhl+s3oRzuXckxjXxJMg66tYLnMzyXVsVkHCuwTWOWkFnzlXhg9vBIuctOB+YpQdnIpY3Jedvuy E9vkk/4Rd2vwzh3xJMQiIzJh4DKAz+m/U3iMALlktJN3URixkNJ0eBbnYgl4IKuOwQ5vXRvstJ4W/ wXnP3FhPg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kl5Zw-0008Ib-JW; Fri, 04 Dec 2020 07:32:32 +0000 Received: from szxga05-in.huawei.com ([45.249.212.191]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kl5Zr-0008HF-GY for linux-arm-kernel@lists.infradead.org; Fri, 04 Dec 2020 07:32:28 +0000 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4CnPXh56xczM0M1; Fri, 4 Dec 2020 15:31:48 +0800 (CST) Received: from DESKTOP-5IS4806.china.huawei.com (10.174.187.37) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.487.0; Fri, 4 Dec 2020 15:32:14 +0800 From: Keqian Zhu To: , , , Subject: [PATCH v3 2/2] clocksource: arm_arch_timer: Correct fault programming of CNTKCTL_EL1.EVNTI Date: Fri, 4 Dec 2020 15:31:26 +0800 Message-ID: <20201204073126.6920-3-zhukeqian1@huawei.com> X-Mailer: git-send-email 2.8.4.windows.1 In-Reply-To: <20201204073126.6920-1-zhukeqian1@huawei.com> References: <20201204073126.6920-1-zhukeqian1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.187.37] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201204_023227_860861_AF765A3D X-CRM114-Status: GOOD ( 13.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Suzuki K Poulose , Marc Zyngier , Keqian Zhu , Daniel Lezcano , Sean Christopherson , Alexios Zavras , Mark Brown , James Morse , Catalin Marinas , wanghaibin.wang@huawei.com, Thomas Gleixner , Will Deacon , Andrew Morton , Julien Thierry Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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. Fixes: 037f637767a8 ("drivers: clocksource: add support for ARM architected timer event stream") Suggested-by: Marc Zyngier Signed-off-by: Keqian Zhu Acked-by: Marc Zyngier --- drivers/clocksource/arm_arch_timer.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 777d38cb39b0..d0177824c518 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -822,15 +822,24 @@ static void arch_timer_evtstrm_enable(int divider) static void arch_timer_configure_evtstream(void) { - int evt_stream_div, pos; + int evt_stream_div, lsb; + + /* + * 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; + + /* + * Find the closest power of two to the divisor. If the adjacent bit + * of lsb (last set bit, starts from 0) is set, then we use (lsb + 1). + */ + lsb = fls(evt_stream_div) - 1; + if (lsb > 0 && (evt_stream_div & BIT(lsb - 1))) + lsb++; - /* Find the closest power of two to the divisor */ - evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ; - pos = fls(evt_stream_div); - if (pos > 1 && !(evt_stream_div & (1 << (pos - 2)))) - pos--; /* enable event stream */ - arch_timer_evtstrm_enable(min(pos, 15)); + arch_timer_evtstrm_enable(max(0, min(lsb, 15))); } static void arch_counter_set_user_access(void)