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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 CB6ABC388F7 for ; Wed, 28 Oct 2020 22:22:17 +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 3F5E4206D4 for ; Wed, 28 Oct 2020 22:22:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ITz5clAs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F5E4206D4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.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=pPsoKQt430oH1nQXRQyo/MEVrlwQCx1sGjRJNfMnOTs=; b=ITz5clAs34+S/3VxIeyf80xdM hGbcINje+7YCu3iK0OsDGEAFo+y0xIhsgVBs3JznS/tLVY7IMTRQEtnu8rvMdMfLCMGtauapRcq9f 1sIclg/nm3icMxj5/54O4VwabWWxhq349LEVBBRmcRREIrlH74RYv0TNJ32NEKgry9gKnXffqgGeq eszyIytElkYJtF3zecmCCWnBGBJv8wtcdc9cMid7WSGjDhAb4jvvr4k1SVvWTg6TLN6tZHBsPJ5ee +OhYxtfdI2eWRwzuwPvP/NkmAOlE8oeEZGxjZBplwigJlsMApZOCZs4IOpQErUtd68AlIbUPL0GHK 723oK9+LA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kXtmx-0008U2-23; Wed, 28 Oct 2020 22:19:27 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kXteE-0004jm-1o for linux-arm-kernel@lists.infradead.org; Wed, 28 Oct 2020 22:10:38 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5F8721AC1; Wed, 28 Oct 2020 15:10:25 -0700 (PDT) Received: from ewhatever.cambridge.arm.com (ewhatever.cambridge.arm.com [10.1.197.1]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 7A3273F68F; Wed, 28 Oct 2020 15:10:24 -0700 (PDT) From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 22/26] coresight: etm4x: Add necessary synchronization for sysreg access Date: Wed, 28 Oct 2020 22:09:41 +0000 Message-Id: <20201028220945.3826358-24-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201028220945.3826358-1-suzuki.poulose@arm.com> References: <20201028220945.3826358-1-suzuki.poulose@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201028_181026_223382_7C208DC9 X-CRM114-Status: GOOD ( 13.88 ) 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: coresight@lists.linaro.org, Suzuki K Poulose , linux-kernel@vger.kernel.org, mathieu.poirier@linaro.org, mike.leach@linaro.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org As per the specification any update to the TRCPRGCTLR must be synchronized by a context synchronization event (in our case an explicist ISB) before the TRCSTATR is checked. Cc: Mike Leach Cc: Mathieu Poirier Signed-off-by: Suzuki K Poulose --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index e36bc1c722c7..4bc2f15b6332 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -178,6 +178,15 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata) /* Disable the trace unit before programming trace registers */ etm4x_relaxed_write32(csa, 0, TRCPRGCTLR); + /* + * If we use system instructions, we need to synchronize the + * write to the TRCPRGCTLR, before accessing the TRCSTATR. + * See ARM IHI0064F, section + * "4.3.7 Synchronization of register updates" + */ + if (!csa->io_mem) + isb(); + /* wait for TRCSTATR.IDLE to go up */ if (coresight_timeout(csa, TRCSTATR, TRCSTATR_IDLE_BIT, 1)) dev_err(etm_dev, @@ -256,6 +265,10 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata) /* Enable the trace unit */ etm4x_relaxed_write32(csa, 1, TRCPRGCTLR); + /* Synchronize the register updates for sysreg access */ + if (!csa->io_mem) + isb(); + /* wait for TRCSTATR.IDLE to go back down to '0' */ if (coresight_timeout(csa, TRCSTATR, TRCSTATR_IDLE_BIT, 0)) dev_err(etm_dev, -- 2.24.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel