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=-8.3 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_SANE_1 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 4425FC35242 for ; Fri, 14 Feb 2020 23:10:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0075F206B6 for ; Fri, 14 Feb 2020 23:10:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="XyWet7eH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727458AbgBNXKz (ORCPT ); Fri, 14 Feb 2020 18:10:55 -0500 Received: from mail-yb1-f193.google.com ([209.85.219.193]:35816 "EHLO mail-yb1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726164AbgBNXKz (ORCPT ); Fri, 14 Feb 2020 18:10:55 -0500 Received: by mail-yb1-f193.google.com with SMTP id p123so5608173ybp.2 for ; Fri, 14 Feb 2020 15:10:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=R4zEiG9M2nzyirDMOJKoPf8/4dfn9S+XuRnFrH9sQ6c=; b=XyWet7eHMyp6S6IWx6Cartw8k9pGGGCDapQO47WtToplCNfHPfc3ZwAgSHrnFMXi5e L7o+OWpOn72Wzqhpzj+lltqH14MsQTaxXwcbcw1aCwTr8f/TUtdoeLRn9eA+k0q4+n3g sZZC1GYjQBpsgCPTahVK2AnM+ZJ3L+ut/9OeoTcEfVU+OBYS6nQqFQKu6ovlhB88o/GW Ah3jHPfAYPU7iD+0FBvS1VDel7UpDIaQhRbC8zVCb9cP/9ID/bKN2Pw1wWsAzISRJym5 QV/tmfZj0pShUXZHkLYi6/vKPxlkBBBoBE1VDHT6L0PcyB5l+TN2PAk3KLz0kGxl3E9I Ph/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=R4zEiG9M2nzyirDMOJKoPf8/4dfn9S+XuRnFrH9sQ6c=; b=OzHPCRnRABqsMAUftDzmGTVmDR9XV6fEjr2cs/704doCcKIOaYU+iXpDezVC+X6MnE 64BxhUoA58+ThFsTcNmPd/dUmKDiVOCM+B/iroQoTo1pYlyl4mffnMhohz4Sl2GdmrsP 505OPPOu7uRGbOzndECD2VckI+PMuj43qP/v0EaPy6hidrc2ZTABucjwi0L67T9nNFlJ VUfdIy0P2w0/mAL8Y6HW3YLjdfRoh9q9nE3Y2g6961FGRjJXyV9lKml9KWejkKXXzEMV Z98/Bqmgiz9dp09dRw1DxxJl6V2BIvRPFQUsb8fIzDdAhETHiPUbIkQ3AZdZhPu8zQ0d qU2Q== X-Gm-Message-State: APjAAAXBMUQbagRtV1posTpyonJ4r4/I/zk8pZdZpVQWnCh65FrnGdq5 qDUGhHoKXBTjLQb4ED2vNYWf0A== X-Google-Smtp-Source: APXvYqyk1bdsJxDMEe/Qm6Vx/7uHGpcCH3yPcLvJFkaX91k7VyiUR506kCrmphDX3fiy8oOvN47Syg== X-Received: by 2002:a25:ad27:: with SMTP id y39mr4844354ybi.517.1581721854000; Fri, 14 Feb 2020 15:10:54 -0800 (PST) Received: from xps15 (S0106002369de4dac.cg.shawcable.net. [68.147.8.254]) by smtp.gmail.com with ESMTPSA id m203sm2908828ywc.10.2020.02.14.15.10.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Feb 2020 15:10:53 -0800 (PST) Date: Fri, 14 Feb 2020 16:10:51 -0700 From: Mathieu Poirier To: Mike Leach Cc: linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org, linux-doc@vger.kernel.org, suzuki.poulose@arm.com Subject: Re: [PATCH v4 6/6] coresight: docs: Add information about the topology representations. Message-ID: <20200214231051.GC20024@xps15> References: <20200211105808.27884-1-mike.leach@linaro.org> <20200211105808.27884-7-mike.leach@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200211105808.27884-7-mike.leach@linaro.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Tue, Feb 11, 2020 at 10:58:08AM +0000, Mike Leach wrote: > Update the CoreSight documents to describe the new connections directory > and the links between CoreSight devices in this directory. > > Signed-off-by: Mike Leach > --- > .../trace/coresight/coresight-ect.rst | 5 +- > Documentation/trace/coresight/coresight.rst | 85 +++++++++++++++++++ > 2 files changed, 89 insertions(+), 1 deletion(-) > Reviewed-by: Mathieu Poirier > 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 >