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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 91024C2D0C3 for ; Mon, 30 Dec 2019 22:32:05 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 620DC20658 for ; Mon, 30 Dec 2019 22:32:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="U6xrTh6t" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 620DC20658 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=kenqm3EwNQdBL7jSBz7HaUgjbNSsL/3///+xIZIsotw=; b=U6xrTh6tqRqkhV glpZ+ihXaL894yOzsqaklLkE33RAYzYZvyqDpVuW0bW0nYXmckVix57bf9uNFg4KSU3D0wlOmsxvD GicLD7N75cab4oCi2h8Uslz+n3FWs1wq5ht5KOV6B63nirfwA2EoheLxP1v0UY+NOkWZtuHZGJghb 3UJmUvFed++gwqDMyb/u7cfsUxFlREEMPQI7wW/e8fqjE30l30gNgkYEEW+Ji4BmqwIc4wyXNicNz Hy9kCCImEcS86SZzaL/Dj30W1vhZxJuuClxwHnqNPeGc2vwLAKjryfKNm7P0WBkK6c5f5UGJbcw2e vfUOmUrlWXW/9GE9BxFQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1im3Zp-0006OW-1n; Mon, 30 Dec 2019 22:31:53 +0000 Received: from [2601:1c0:6280:3f0::34d9] by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1im3Zm-0006NR-Du; Mon, 30 Dec 2019 22:31:50 +0000 Subject: Re: [PATCH v7 13/15] docs: coresight: Update documentation for CoreSight to cover CTI. To: Mike Leach , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, coresight@lists.linaro.org, linux-doc@vger.kernel.org References: <20191230164441.28375-1-mike.leach@linaro.org> From: Randy Dunlap Message-ID: <5948ee00-c3e8-749d-2354-5089b0103cee@infradead.org> Date: Mon, 30 Dec 2019 14:31:48 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.1 MIME-Version: 1.0 In-Reply-To: <20191230164441.28375-1-mike.leach@linaro.org> Content-Language: en-US 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: lorenzo.pieralisi@arm.com, mathieu.poirier@linaro.org, suzuki.poulose@arm.com, linux-arm-msm@vger.kernel.org, corbet@lwn.net, liviu.dudau@arm.com, agross@kernel.org, robh+dt@kernel.org, maxime@cerno.tech, sudeep.holla@arm.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Mike, Just a couple of small nits below. On 12/30/19 8:44 AM, Mike Leach wrote: > Add new document covering CTI / CTM usage in CoreSight. > > Add section in coresight.rst introducing CTI and CTM modules with link > to new document. > > Signed-off-by: Mike Leach > Reviewed-by: Suzuki K Poulose > Reviewed-by: Mathieu Poirier > --- > .../trace/coresight/coresight-ect.rst | 211 ++++++++++++++++++ > Documentation/trace/coresight/coresight.rst | 13 ++ > 2 files changed, 224 insertions(+) > create mode 100644 Documentation/trace/coresight/coresight-ect.rst > > diff --git a/Documentation/trace/coresight/coresight-ect.rst b/Documentation/trace/coresight/coresight-ect.rst > new file mode 100644 > index 000000000000..3e06588f24fa > --- /dev/null > +++ b/Documentation/trace/coresight/coresight-ect.rst > @@ -0,0 +1,211 @@ > +============================================= > +CoreSight Embedded Cross Trigger (CTI & CTM). > +============================================= > + > + :Author: Mike Leach > + :Date: November 2019 > + > +Hardware Description > +-------------------- > + > +The CoreSight Cross Trigger Interface (CTI) is a hardware device that takes > +individual input and output hardware signals known as triggers to and from > +devices and interconnects them via the Cross Trigger Matrix (CTM) to other > +devices via numbered channels, in order to propagate events between devices. > + > +e.g.:: > + > + 0000000 in_trigs ::::::: > + 0 C 0----------->: : +======>(other CTI channel IO) > + 0 P 0<-----------: : v > + 0 U 0 out_trigs : : Channels ***** ::::::: > + 0000000 : CTI :<=========>*CTM*<====>: CTI :---+ > + ####### in_trigs : : (id 0-3) ***** ::::::: v > + # ETM #----------->: : ^ ####### > + # #<-----------: : +---# ETR # > + ####### out_trigs ::::::: ####### > + > +The CTI driver enables the programming of the CTI to attach triggers to > +channels. When an input trigger becomes active, the attached channel will > +become active. Any output trigger attached to that channel will also > +become active. The active channel is propagated to other CTIs via the CTM, > +activating connected output triggers there, unless filtered by the CTI > +channel gate. > + > +It is also possible to activate a channel using system software directly > +programming registers in the CTI. > + > +The CTIs are registered by the system to be associated with CPUs and/or other > +CoreSight devices on the trace data path. When these devices are enabled the > +attached CTIs will also be enabled. By default/on power up the CTIs have > +no programmed trigger/channel attachments, so will not affect the system > +until explicitly programmed. > + > +The hardware trigger connections between CTIs and devices is implementation > +defined, unless the CPU/ETM combination is a v8 architecture, in which case > +the connections have an architecturally defined standard layout. > + > +The hardware trigger signals can also be connected to non-CoreSight devices > +(e.g. UART), or be propagated off chip as hardware IO lines. > + > +All the CTI devices are associated with a CTM. On many systems there will be a > +single effective CTM (one CTM, or multiple CTMs all interconnected), but it is > +possible that systems can have nets of CTIs+CTM that are not interconnected by > +a CTM to each other. On these systems a CTM index is declared to associate > +CTI devices that are interconnected via a given CTM. > + > +Sysfs files and directories > +--------------------------- > + > +The CTI devices appear on the existing CoreSight bus alongside the other > +CoreSight devices:: > + > + >$ ls /sys/bus/coresight/devices > + cti_cpu0 cti_cpu2 cti_sys0 etm0 etm2 funnel0 replicator0 tmc_etr0 > + cti_cpu1 cti_cpu3 cti_sys1 etm1 etm3 funnel1 tmc_etf0 tpiu0 > + > +The ``cti_cpu`` named CTIs are associated with a CPU, and any ETM used by > +that core. the ``cti_sys`` CTIs are general system infrastructure CTIs that The > +can be associated with other CoreSight devices, or other system hardware > +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 > + > +*Key file items are:-* > + * ``enable``: enables/disables the CTI. > + * ``ctmid`` : associated CTM - only relevant if system has multiple CTI+CTM > + clusters that are not interconnected. > + * ``nr_trigger_cons`` : total connections - triggers directories. > + > +*Sub-directories:-* > + * ``triggers``: contains list of triggers for an individual connection. > + * ``channels``: Contains the channel API - CTI main programming interface. > + * ``regs``: Gives access to the raw programmable CTI regs. > + * ``mgmt``: the standard CoreSight management registers. > + > + > +triggers directories > +~~~~~~~~~~~~~~~~~~~~~~~ > + > +Individual trigger connection information. This describes trigger signals for > +CoreSight and non-CoreSight connections. > + > +Each triggers directory has a set of parameters describing the triggers for > +the connection. > + > + * ``name`` : name of connection > + * ``in_signals`` : input trigger signal indexes used in this connection. > + * ``in_types`` : functional types for in signals. > + * ``out_signals`` : output trigger signals for this connection. > + * ``out_types`` : functional types for out signals. > + > +e.g:: > + > + >$ ls ./cti_cpu0/triggers0/ > + in_signals in_types name out_signals out_types > + >$ cat ./cti_cpu0/triggers0/name > + cpu0 > + >$ cat ./cti_cpu0/triggers0/out_signals > + 0-2 > + >$ cat ./cti_cpu0/triggers0/out_types > + pe_edbgreq pe_dbgrestart pe_ctiirq > + >$ cat ./cti_cpu0/triggers0/in_signals > + 0-1 > + >$ cat ./cti_cpu0/triggers0/in_types > + pe_dbgtrigger pe_pmuirq > + > +If a connection has zero signals in either the 'in' or 'out' triggers then > +those parameters will be omitted. > + > +Channels API Directory > +~~~~~~~~~~~~~~~~~~~~~~ > + > +This provides an easy way to attach triggers to channels, without needing > +the multiple register operations that are required if manipulating the > +'regs' sub-dir elements directly. spell out: sub-directory > + > +A number of files provide this API:: > + > + >$ ls ./cti_sys0/channels/ > + chan_clear chan_inuse chan_xtrigs_view trigin_detach > + chan_free chan_pulse chan_xtrigs_view_sel trigout_attach > + chan_gate_disable chan_set trig_filter_enable trigout_detach > + chan_gate_enable chan_xtrigs_reset trigin_attach trigout_filtered > + > +Most access to these elements take the form:: > + > + echo [] > // > + > +where the optional is only needed for trigXX_attach | detach > +operations. > + > +e.g.:: > + > + >$ echo 0 1 > ./cti_sys0/channels/trigout_attach > + >$ echo 0 > ./cti_sys0/channels/chan_set > + > +Attaches trigout(1) to channel(0), then activates channel(0) generating a > +set state on cti_sys0.trigout(1) > + > + > +*API operations* > + > + * ``trigin_attach, trigout_attach``: Attach a channel to a trigger signal. > + * ``trigin_detach, trigout_detach``: Detach a channel from a trigger signal. > + * ``chan_set``: Set the channel - the set state will be propagated around > + the CTM to other connected devices. > + * ``chan_clear``: Clear the channel. > + * ``chan_pulse``: Set the channel for a single CoreSight clock cycle. > + * ``chan_gate_enable``: Write operation sets the CTI gate to propagate > + (enable) the channel to other devices. This operation takes a channel > + number. CTI gate is enabled for all channels by default at power up. Read > + to list the currently enabled channels on the gate. > + * ``chan_gate_disable``: Write channel number to disable gate for that > + channel. > + * ``chan_inuse``: Show the current channels attached to any signal > + * ``chan_free``: Show channels with no attached signals. > + * ``chan_xtrig_view``: write a channel number to select a channel to view, > + read to show the cross triggers programmed for the selected channel. > + * ``trig_filter_enable``: Defaults to enabled, disable to allow potentially > + dangerous output signals to be set. > + * ``trigout_filtered``: Trigger out signals that are prevented from being > + set if filtering ``trig_filter_enable`` is enabled. One use is to prevent > + accidental ``EDBGREQ`` signals stopping a core. > + * ``chan_xtrigs_reset``: Write 1 to clear all channel / trigger programming. > + Resets device hardware to default state. > + > + > +The example below attaches input trigger index 1 to channel 2, and output > +trigger index 6 to the same channel. It then examines the state of the > +channel / trigger connections using the appropriate sysfs attributes. > + > +The settings mean that if either input trigger 1, or channel 2 go active then > +trigger out 6 will go active. We then enable the CTI, and use the software > +channel control to activate channel 2. We see the active channel on the > +``choutstatus`` register and the active signal on the ``trigoutstatus`` > +register. Finally clearing the channel removes this. > + > +e.g.:: > + > + .../cti_sys0/channels# echo 2 1 > trigin_attach > + .../cti_sys0/channels# echo 2 6 > trigout_attach > + .../cti_sys0/channels# cat chan_free > + 0-1,3 > + .../cti_sys0/channels# cat chan_inuse > + 2 > + .../cti_sys0/channels# echo 2 > chan_xtrigs_view > + .../cti_sys0/channels# cat chan_xtrigs_view > + [2] IN: 1 OUT: 6 > + .../cti_sys0/# echo 1 > enable > + .../cti_sys0/channels# echo 2 > chan_set > + .../cti_sys0/channels# cat ../regs/choutstatus > + 0x4 > + .../cti_sys0/channels# cat ../regs/trigoutstatus > + 0x40 > + .../cti_sys0/channels# echo 2 > chan_clear > + .../cti_sys0/channels# cat ../regs/trigoutstatus > + 0x0 > + .../cti_sys0/channels# cat ../regs/choutstatus > + 0x0 Reviewed-by: Randy Dunlap thanks. -- ~Randy _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel