From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752392AbeENSyw (ORCPT ); Mon, 14 May 2018 14:54:52 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:46744 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752250AbeENSyu (ORCPT ); Mon, 14 May 2018 14:54:50 -0400 Subject: Re: [PATCH v2] coresight: documentation: update sysfs section To: Kim Phillips , Mathieu Poirier Cc: Jonathan Corbet , linux-arm-kernel , "open list:DOCUMENTATION" , linux-kernel@vger.kernel.org References: <20180507172915.c032cd71c07b1849bf419a5f@arm.com> <20180514121959.a9a3d2fb3d3d270849ffbc39@arm.com> From: Randy Dunlap Message-ID: Date: Mon, 14 May 2018 11:54:48 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180514121959.a9a3d2fb3d3d270849ffbc39@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/14/2018 10:19 AM, Kim Phillips wrote: > - Align and show updated ls devices output from the TC2, based on > current driver > > - Provide an example from an ETMv4 based system (Juno) > > - Reflect changes to the way the RAM write pointer is accessed since > it got changed in commit 7d83d17795ef ("coresight: tmc: adding sysFS > management entries"). > > Cc: Mathieu Poirier > Cc: Jonathan Corbet > Signed-off-by: Kim Phillips > --- > v2: address Mathieu's comment about clarifying the sinks on the Juno > vs. TC2 platforms. > > Documentation/trace/coresight.txt | 41 +++++++++++++++++++------------ > 1 file changed, 25 insertions(+), 16 deletions(-) > > diff --git a/Documentation/trace/coresight.txt > b/Documentation/trace/coresight.txt index 6f0120c3a4f1..134994e9fa6d > 100644 > --- a/Documentation/trace/coresight.txt > +++ b/Documentation/trace/coresight.txt > @@ -144,10 +144,22 @@ If everything goes well during the registration > process the new devices will show up under /sys/bus/coresight/devices, > as showns here for a TC2 platform: as shown here > root:~# ls /sys/bus/coresight/devices/ > -replicator 20030000.tpiu 2201c000.ptm 2203c000.etm 2203e000.etm > -20010000.etb 20040000.funnel 2201d000.ptm 2203d000.etm > +20010000.etb 20040000.funnel 2201d000.ptm 2203d000.etm > replicator +20030000.tpiu 2201c000.ptm 2203c000.etm > 2203e000.etm root:~# > > +and here for a Juno platform: > + > +root@juno:~# ls /sys/bus/coresight/devices/ > +20010000.etf 20120000.replicator 22040000.etm > 230c0000.funnel +20030000.tpiu 20130000.funnel > 220c0000.funnel 23140000.etm +20040000.funnel > 20140000.etf 22140000.etm 23240000.etm > +20070000.etr 20150000.funnel 23040000.etm > 23340000.etm +root@juno:~# + > +Note that on Juno users can select the ETF, ETR and TPIU as a sink > target while +on TC2, the ETB and TPIU can be selected. > + > The functions take a "struct coresight_device", which looks like this: > > struct coresight_desc { > @@ -193,16 +205,16 @@ the information carried in "THIS_MODULE". > How to use the tracer modules > ----------------------------- > > -Before trace collection can start, a coresight sink needs to be > identify. +Before trace collection can start, a coresight sink needs to The - and + lines seems to be merged... > be identified. There is no limit on the amount of sinks (nor sources) > that can be enabled at any given moment. As a generic operation, all > device pertaining to the sink class will have an "active" entry in > sysfs: > root:/sys/bus/coresight/devices# ls > -replicator 20030000.tpiu 2201c000.ptm 2203c000.etm 2203e000.etm > -20010000.etb 20040000.funnel 2201d000.ptm 2203d000.etm > +20010000.etb 20040000.funnel 2201d000.ptm 2203d000.etm > replicator +20030000.tpiu 2201c000.ptm 2203c000.etm > 2203e000.etm root:/sys/bus/coresight/devices# ls 20010000.etb > -enable_sink status trigger_cntr > +enable_sink mgmt power subsystem trigger_cntr uevent > root:/sys/bus/coresight/devices# echo 1 > 20010000.etb/enable_sink > root:/sys/bus/coresight/devices# cat 20010000.etb/enable_sink > 1 > @@ -216,16 +228,13 @@ trigger a trace capture: > root:/sys/bus/coresight/devices# echo 1 > 2201c000.ptm/enable_source > root:/sys/bus/coresight/devices# cat 2201c000.ptm/enable_source > 1 > -root:/sys/bus/coresight/devices# cat 20010000.etb/status > -Depth: 0x2000 > -Status: 0x1 > -RAM read ptr: 0x0 > -RAM wrt ptr: 0x19d3 <----- The write pointer is moving > -Trigger cnt: 0x0 > -Control: 0x1 > -Flush status: 0x0 > -Flush ctrl: 0x2001 > -root:/sys/bus/coresight/devices# > + > +Observe the write pointer moving: > + > +root:/sys/bus/coresight/devices# cat 20010000.etb/mgmt/rwp > +0x1a8 > +root:/sys/bus/coresight/devices# cat 20010000.etb/mgmt/rwp > +0x19a6 > > Trace collection is stopped the same way: > > -- ~Randy