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=-9.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 2EC03C34022 for ; Thu, 27 Feb 2020 15:14:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F009324688 for ; Thu, 27 Feb 2020 15:14:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="n3dfJoV3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730475AbgB0POh (ORCPT ); Thu, 27 Feb 2020 10:14:37 -0500 Received: from mail-wm1-f41.google.com ([209.85.128.41]:55008 "EHLO mail-wm1-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729910AbgB0POh (ORCPT ); Thu, 27 Feb 2020 10:14:37 -0500 Received: by mail-wm1-f41.google.com with SMTP id z12so3983465wmi.4 for ; Thu, 27 Feb 2020 07:14:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=0dvq0TIvLIhYW6FRHb2k6j4t1FaEUBN90K81y+vKrss=; b=n3dfJoV3D6qtoScNIKFTLoXkidqgBL9BgtF6Y4SweATy7nHjRMGikNNWjPH/JLrt2g 5hWx1D+DIFycvH62F1+p8Ie8w8AfTz821Uzb0TAbtnFxUJw+q4URbDYjG84wx8Ue32iE 0jb5//mN0QFp334ZGFkDA2WJnMNoHOwcelt+NLw5t55RbTzKMNIkin2cFMv6b5JzWzr0 rwbII38y+SkKSK7a/KiX6l882RelEgCAAHH/7LEWEW2K1A2Ni90sUAbwmrIOrlswEP0b A8fpW1MzM+diCyT4l5bhEdp9Q04oS9OUWKS1Ue0/uW8FVdpDrLp9hLcw0443S9oWLpaX Be9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=0dvq0TIvLIhYW6FRHb2k6j4t1FaEUBN90K81y+vKrss=; b=dbB27HC7rkMeIfFJMIk8r2KghKKutQuTOGCKggIZlIuUvGBMa9VS9mokBzxYaMIPGU 4hxDCoDE6HwLEEuYOmTwcxKFkzCykVJOJWIXGTgh6xPsz8rhvpZj2icRVnGO6tAk/1kN hzofdwN9Y5Dx8CvwSTRnbgoYqzUIyzEO8CEpyTvu/9AWGrXuykCXctIVp6vPJnldmC3F C/y1op1YzJHLzsEAr1egQs0CdpK/MpLIY5cy1iVpaQKBecrB+ZA813dJ4cHBBqWm4wyi xGygvACZ++BThFVSNTnhOj75UL1YeXX57mSVfPehZL8h37bKeJuZpy1FYcbfhVjqIxMw xtJQ== X-Gm-Message-State: APjAAAWL+i4aKVlHevT5mi+iN9bVFHs9Hj8xl3zXw/ZNYkb5wlu81R9Q qopyxxaWY8tSEIZxsiInw2K0uQ== X-Google-Smtp-Source: APXvYqzyZ0jyt4lFW5kshD8LLCN+heer9j/vnrZt0b0UOmMwmVFlpTvo+3iTRCXmNrQPH0rFQ8WXmg== X-Received: by 2002:a05:600c:149:: with SMTP id w9mr10823wmm.132.1582816473630; Thu, 27 Feb 2020 07:14:33 -0800 (PST) Received: from linaro.org ([2a00:23c5:6801:1801:2dc1:e60d:4b1c:70e0]) by smtp.gmail.com with ESMTPSA id q12sm8973079wrg.71.2020.02.27.07.14.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Feb 2020 07:14:32 -0800 (PST) From: Mike Leach To: linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org, linux-doc@vger.kernel.org Cc: mathieu.poirier@linaro.org, suzuki.poulose@arm.com, Mike Leach Subject: [PATCH v5 6/6] coresight: docs: Add information about the topology representations Date: Thu, 27 Feb 2020 15:14:16 +0000 Message-Id: <20200227151416.14271-7-mike.leach@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200227151416.14271-1-mike.leach@linaro.org> References: <20200227151416.14271-1-mike.leach@linaro.org> Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Update the CoreSight documents to describe the new connections directory and the links between CoreSight devices in this directory. Signed-off-by: Mike Leach Reviewed-by: Mathieu Poirier --- .../trace/coresight/coresight-ect.rst | 5 +- Documentation/trace/coresight/coresight.rst | 85 +++++++++++++++++++ 2 files changed, 89 insertions(+), 1 deletion(-) diff --git a/Documentation/trace/coresight/coresight-ect.rst b/Documentation/trace/coresight/coresight-ect.rst index 067cee91c857..3539af895832 100644 --- a/Documentation/trace/coresight/coresight-ect.rst +++ b/Documentation/trace/coresight/coresight-ect.rst @@ -71,7 +71,7 @@ capable of generating or using trigger signals.:: >$ ls /sys/bus/coresight/devices/etm0/cti_cpu0 channels ctmid enable nr_trigger_cons mgmt power regs subsystem - triggers0 triggers1 uevent + connections triggers0 triggers1 uevent *Key file items are:-* * ``enable``: enables/disables the CTI. @@ -84,6 +84,9 @@ capable of generating or using trigger signals.:: * ``channels``: Contains the channel API - CTI main programming interface. * ``regs``: Gives access to the raw programmable CTI regs. * ``mgmt``: the standard CoreSight management registers. + * ``connections``: Links to connected *CoreSight* devices. The number of + links can be 0 to ``nr_trigger_cons``. Actual number given by ``nr_links`` + in this directory. triggers directories diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst index 108600ee1e12..0b73acb44efa 100644 --- a/Documentation/trace/coresight/coresight.rst +++ b/Documentation/trace/coresight/coresight.rst @@ -241,6 +241,91 @@ to the newer scheme, to give a confirmation that what you see on your system is not unexpected. One must use the "names" as they appear on the system under specified locations. +Topology Representation +----------------------- + +Each CoreSight component has a ``connections`` directory which will contain +links to other CoreSight components. This allows the user to explore the trace +topology and for larger systems, determine the most appropriate sink for a +given source. The connection information can also be used to establish +which CTI devices are connected to a given component. This directory contains a +``nr_links`` attribute detailing the number of links in the directory. + +For an ETM source, in this case ``etm0`` on a Juno platform, a typical +arrangement will be:: + + linaro-developer:~# ls - l /sys/bus/coresight/devices/etm0/connections + cti_cpu0 -> ../../../23020000.cti/cti_cpu0 + nr_links + out:0 -> ../../../230c0000.funnel/funnel2 + +Following the out port to ``funnel2``:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/funnel2/connections + in:0 -> ../../../23040000.etm/etm0 + in:1 -> ../../../23140000.etm/etm3 + in:2 -> ../../../23240000.etm/etm4 + in:3 -> ../../../23340000.etm/etm5 + nr_links + out:0 -> ../../../20040000.funnel/funnel0 + +And again to ``funnel0``:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/funnel0/connections + in:0 -> ../../../220c0000.funnel/funnel1 + in:1 -> ../../../230c0000.funnel/funnel2 + nr_links + out:0 -> ../../../20010000.etf/tmc_etf0 + +Finding the first sink ``tmc_etf0``. This can be used to collect data +as a sink, or as a link to propagate further along the chain:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/tmc_etf0/connections + cti_sys0 -> ../../../20020000.cti/cti_sys0 + in:0 -> ../../../20040000.funnel/funnel0 + nr_links + out:0 -> ../../../20150000.funnel/funnel4 + +via ``funnel4``:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/funnel4/connections + in:0 -> ../../../20010000.etf/tmc_etf0 + in:1 -> ../../../20140000.etf/tmc_etf1 + nr_links + out:0 -> ../../../20120000.replicator/replicator0 + +and a ``replicator0``:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/replicator0/connections + in:0 -> ../../../20150000.funnel/funnel4 + nr_links + out:0 -> ../../../20030000.tpiu/tpiu0 + out:1 -> ../../../20070000.etr/tmc_etr0 + +Arriving at the final sink in the chain, ``tmc_etr0``:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/tmc_etr0/connections + cti_sys0 -> ../../../20020000.cti/cti_sys0 + in:0 -> ../../../20120000.replicator/replicator0 + nr_links + +As described below, when using sysfs it is sufficient to enable a sink and +a source for successful trace. The framework will correctly enable all +intermediate links as required. + +Note: ``cti_sys0`` appears in two of the connections lists above. +CTIs can connect to multiple devices and are arranged in a star topology +via the CTM. See (:doc:`coresight-ect`) [#fourth]_ for further details. +Looking at this device we see 4 connections:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/cti_sys0/connections + nr_links + stm0 -> ../../../20100000.stm/stm0 + tmc_etf0 -> ../../../20010000.etf/tmc_etf0 + tmc_etr0 -> ../../../20070000.etr/tmc_etr0 + tpiu0 -> ../../../20030000.tpiu/tpiu0 + + How to use the tracer modules ----------------------------- -- 2.17.1