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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 C4367C43331 for ; Tue, 24 Mar 2020 13:15:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9A99A208D6 for ; Tue, 24 Mar 2020 13:15:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585055755; bh=OVFFe6LVDT1McSdceRcLJ0lU84O4es66sWRpFFWGBb4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=zi7c83D3axA4cENuV457Tz2nbkL7gRTCpYnz3mCqGzukcGmceOQn2y5CkWbMaUa+l x6uBJQ/as3tu3YxiJ9EBpNldfh56+Y0mCBKHZRroe71i8ctpCmkzTcBbsdkXT+hVaf 5IenJxt1vzdoB8ORqfs7oAiEHUuJ8h3WD3Bd7c90= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728334AbgCXNPy (ORCPT ); Tue, 24 Mar 2020 09:15:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:35024 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728217AbgCXNPx (ORCPT ); Tue, 24 Mar 2020 09:15:53 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 C1150206F6; Tue, 24 Mar 2020 13:15:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585055752; bh=OVFFe6LVDT1McSdceRcLJ0lU84O4es66sWRpFFWGBb4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KLkZsk9mhfBz4Izod+3RLXASE6UorwLim3tTVqi1FGTNFO+wZB1k4XwQjAiYul9+2 3d6TqgBN7rFtSBI+egJyd3TnXBCpS7fv68EOVavJzvKkdPoqudP2PmsclKrijYfJC+ VF66Xti/dBE4E0/2ilAUtG4Ytv/euu5kv6w0HJW0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Joakim Zhang , Will Deacon , Sasha Levin Subject: [PATCH 5.4 018/102] drivers/perf: fsl_imx8_ddr: Correct the CLEAR bit definition Date: Tue, 24 Mar 2020 14:10:10 +0100 Message-Id: <20200324130808.390666280@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200324130806.544601211@linuxfoundation.org> References: <20200324130806.544601211@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joakim Zhang [ Upstream commit 049d919168458ac54e7fad27cd156a958b042d2f ] When disabling a counter from ddr_perf_event_stop(), the counter value is reset to 0 at the same time. Preserve the counter value by performing a read-modify-write of the PMU register and clearing only the enable bit. Signed-off-by: Joakim Zhang Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- drivers/perf/fsl_imx8_ddr_perf.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/perf/fsl_imx8_ddr_perf.c b/drivers/perf/fsl_imx8_ddr_perf.c index 0e51baa48b149..6eef47de8fccc 100644 --- a/drivers/perf/fsl_imx8_ddr_perf.c +++ b/drivers/perf/fsl_imx8_ddr_perf.c @@ -327,9 +327,10 @@ static void ddr_perf_counter_enable(struct ddr_pmu *pmu, int config, if (enable) { /* - * must disable first, then enable again - * otherwise, cycle counter will not work - * if previous state is enabled. + * cycle counter is special which should firstly write 0 then + * write 1 into CLEAR bit to clear it. Other counters only + * need write 0 into CLEAR bit and it turns out to be 1 by + * hardware. Below enable flow is harmless for all counters. */ writel(0, pmu->base + reg); val = CNTL_EN | CNTL_CLEAR; @@ -337,7 +338,8 @@ static void ddr_perf_counter_enable(struct ddr_pmu *pmu, int config, writel(val, pmu->base + reg); } else { /* Disable counter */ - writel(0, pmu->base + reg); + val = readl_relaxed(pmu->base + reg) & CNTL_EN_MASK; + writel(val, pmu->base + reg); } } -- 2.20.1