From patchwork Mon Apr 5 16:43:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suzuki K Poulose X-Patchwork-Id: 12183335 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=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 6D6F4C433B4 for ; Mon, 5 Apr 2021 16:48:23 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 86E11611AF for ; Mon, 5 Apr 2021 16:48:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 86E11611AF 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=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=f0g1bEtbab0IFoLYWmPVUdcx+yJnd3zcQoy1gUZDsBM=; b=ZGM8+8vQZMHkevvlY6KvoMiD8 Kz2lhbCC5JapVyeRrThumJ4JX+/purECAzbP9PbhcXuhH+dq0sOb/C61itC5cTm+nQsuP9bj6rwh0 qSdaRy+TMZ0IJFfYUSkwYfdkEpMoB12592Q0d4YlNeiUf5Dp1VGgvcf/kaRuFHREJhaOzA9fHEKjm s5GkOc6ofWBn5Xm+oIdSVVsqIFGyvirFlWtmU79TlUsJd0DmAMhnkg69jpHYaqN0OE0vyEhKi2wnl TnF/iJCYm0Q1ae6jqTP94A2wKWmf1HuUEPNU9rZngEIlywm6LcRizp7MmF6qKENN8kdeKRbxlEloD Wl8XGnuQQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lTSNV-0009zb-7n; Mon, 05 Apr 2021 16:47:05 +0000 Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lTSKa-0008NV-13 for linux-arm-kernel@lists.infradead.org; Mon, 05 Apr 2021 16:44:06 +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 1BA401424; Mon, 5 Apr 2021 09:44:03 -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 3994D3F694; Mon, 5 Apr 2021 09:44:01 -0700 (PDT) From: Suzuki K Poulose To: maz@kernel.org, mathieu.poirier@linaro.org Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, anshuman.khandual@arm.com, mike.leach@linaro.org, catalin.marinas@arm.com, will@kernel.org, peterz@infradead.org, leo.yan@linaro.org, robh@kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org, Suzuki K Poulose Subject: [PATCH v6 19/20] Documentation: trace: Add documentation for TRBE Date: Mon, 5 Apr 2021 17:43:06 +0100 Message-Id: <20210405164307.1720226-20-suzuki.poulose@arm.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20210405164307.1720226-1-suzuki.poulose@arm.com> References: <20210405164307.1720226-1-suzuki.poulose@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210405_174404_311483_F6F6B0D4 X-CRM114-Status: GOOD ( 12.93 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Anshuman Khandual Add documentation for the TRBE under trace/coresight. Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Reviewed-by: Mathieu Poirier Signed-off-by: Anshuman Khandual [ Split from the TRBE driver patch ] Signed-off-by: Suzuki K Poulose --- .../trace/coresight/coresight-trbe.rst | 38 +++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 Documentation/trace/coresight/coresight-trbe.rst diff --git a/Documentation/trace/coresight/coresight-trbe.rst b/Documentation/trace/coresight/coresight-trbe.rst new file mode 100644 index 000000000000..b9928ef148da --- /dev/null +++ b/Documentation/trace/coresight/coresight-trbe.rst @@ -0,0 +1,38 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============================== +Trace Buffer Extension (TRBE). +============================== + + :Author: Anshuman Khandual + :Date: November 2020 + +Hardware Description +-------------------- + +Trace Buffer Extension (TRBE) is a percpu hardware which captures in system +memory, CPU traces generated from a corresponding percpu tracing unit. This +gets plugged in as a coresight sink device because the corresponding trace +generators (ETE), are plugged in as source device. + +The TRBE is not compliant to CoreSight architecture specifications, but is +driven via the CoreSight driver framework to support the ETE (which is +CoreSight compliant) integration. + +Sysfs files and directories +--------------------------- + +The TRBE devices appear on the existing coresight bus alongside the other +coresight devices:: + + >$ ls /sys/bus/coresight/devices + trbe0 trbe1 trbe2 trbe3 + +The ``trbe`` named TRBEs are associated with a CPU.:: + + >$ ls /sys/bus/coresight/devices/trbe0/ + align flag + +*Key file items are:-* + * ``align``: TRBE write pointer alignment + * ``flag``: TRBE updates memory with access and dirty flags