From patchwork Mon Dec 14 17:37:25 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: 11972587 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 BF490C4361B for ; Mon, 14 Dec 2020 17:44:08 +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 71766207A0 for ; Mon, 14 Dec 2020 17:44:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 71766207A0 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=rM0zIrbkw5H5fWjNeQ+k2KlGRICBTIxFrJgR8nwr7Cw=; b=L4y+XBjmUHJ4lpSfit4O+cWHz cVKvdNQqvzEkgPwOit9ZkQzgAVs5SngeXS0YuKwD2zCg8ZW916G9QOM4pk3wpfzf2K1M8gg8JjjYl lp0qX/WlHU5Iq/F6w8e2v0WBjWsVU8r0s8Dd+9GUkIQbm68/m77pV9LVt7e0UDeQWk0POQ1HCcPPH jMrqyae04brWvHTfwb6176W5XfaOkpWPuifsqV4FpQTpY3V8xwRWIJ7LEyzYoM8lAGVdbx8WKaO5u wGoTrR79Fng16KM66ahqB0uJSJLffhz4MCbUHw9b4wB27PzQ25MfvNDgKtg2omwt7Zr2oqv5WBOHO tWvU8AbxA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1korrL-0007IH-Rk; Mon, 14 Dec 2020 17:42:07 +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 1kornW-0005JY-VP for linux-arm-kernel@lists.infradead.org; Mon, 14 Dec 2020 17:38:12 +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 8C62A1480; Mon, 14 Dec 2020 09:38:10 -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 528103F66E; Mon, 14 Dec 2020 09:38:09 -0800 (PST) From: Suzuki K Poulose To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 19/25] coresight: etm4x: Add necessary synchronization for sysreg access Date: Mon, 14 Dec 2020 17:37:25 +0000 Message-Id: <20201214173731.302520-20-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201214173731.302520-1-suzuki.poulose@arm.com> References: <20201214173731.302520-1-suzuki.poulose@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201214_123811_136790_DE41DAEA X-CRM114-Status: GOOD ( 13.65 ) 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, Suzuki K Poulose , catalin.marinas@arm.com, linux-kernel@vger.kernel.org, leo.yan@linaro.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 128390f9b7fd..366fae810b55 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,