From patchwork Thu Nov 19 16:45:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suzuki K Poulose X-Patchwork-Id: 11918353 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=-16.8 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=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 11ACFC6369E for ; Thu, 19 Nov 2020 16:54:32 +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 725E424199 for ; Thu, 19 Nov 2020 16:54:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="bIBRWe8y" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 725E424199 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=YYs/GlffLn1+ycP0OaKzhSqztSbI3V345jS6Ogi0TZ8=; b=bIBRWe8yyJ0ezpu96g69950om lxh0sDJ60wvsFgIUXYktdCSdBFxJeQfnfnc37Ri0BirvpcKCrmF5hgh3ePoY0btv14g7GH9Aj4pfn wpr4zZlRgfe4lJQQ6qdy9p7AS9zxyW+Zz28cgDcX1Fsbk69iIzDcWT4ZNgFkAKdSK6SzagV0KNTZ4 vTYPR7Mubv3lYa8YhTfkFm+aOaovNNr2TXGwbEfvrvW4H5qALZznpkGSyxcZiglIjBxqaeK+VpUUr Eo+nkyRFe+TwQ0x9duIHA2tn4iYizJt/x0yTrlFFWPdUBPTsjEP9aSl2Pm4HjsNSsGQcfjC2VUQx+ WjRSCweyA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kfnBc-0003sb-PN; Thu, 19 Nov 2020 16:53:32 +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 1kfn4m-0000z5-RP for linux-arm-kernel@lists.infradead.org; Thu, 19 Nov 2020 16:46:48 +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 5477815EC; Thu, 19 Nov 2020 08:46:28 -0800 (PST) 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 D577F3F718; Thu, 19 Nov 2020 08:46:26 -0800 (PST) From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v4 19/25] coresight: etm4x: Add necessary synchronization for sysreg access Date: Thu, 19 Nov 2020 16:45:41 +0000 Message-Id: <20201119164547.2982871-20-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201119164547.2982871-1-suzuki.poulose@arm.com> References: <20201119164547.2982871-1-suzuki.poulose@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201119_114629_098742_11469C39 X-CRM114-Status: GOOD ( 13.83 ) 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: mathieu.poirier@linaro.org, anshuman.khandual@arm.com, coresight@lists.linaro.org, Suzuki K Poulose , linux-kernel@vger.kernel.org, jonathan.zhouwen@huawei.com, mike.leach@linaro.org 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 Reviewed-by: 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 f1908e6f2180..7ac0a185c146 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -187,6 +187,15 @@ 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, @@ -265,6 +274,10 @@ 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,