From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752465AbdASLk2 (ORCPT ); Thu, 19 Jan 2017 06:40:28 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:39698 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752444AbdASLkZ (ORCPT ); Thu, 19 Jan 2017 06:40:25 -0500 Date: Thu, 19 Jan 2017 12:40:37 +0100 From: Greg KH To: Suzuki K Poulose Cc: mathieu.poirier@linaro.org, zhang.chunyan@linaro.org, pratikp@codeaurora.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, stable@vger.kernel.org Subject: Re: [PATCH] coresight: STM: Balance enable/disable Message-ID: <20170119114037.GR28024@kroah.com> References: <1484589600-21397-1-git-send-email-suzuki.poulose@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1484589600-21397-1-git-send-email-suzuki.poulose@arm.com> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 16, 2017 at 06:00:00PM +0000, Suzuki K Poulose wrote: > The stm is automatically enabled when an application sets the policy > via ->link() call back by using coresight_enable(), which keeps the > refcount of the current users of the STM. However, the unlink() callback > issues stm_disable() directly, which leaves the STM turned off, without > the coresight layer knowing about it. This prevents any further uses > of the STM hardware as the coresight layer still thinks the STM is > turned on and doesn't enable the hardware when required. Even manually > enabling the STM via sysfs can't really enable the hw. > > e.g, > > $ echo 1 > $CS_DEVS/$ETR/enable_sink > $ mkdir -p $CONFIG_FS/stp-policy/$source.0/stm_test/ > $ echo 32768 65535 > $CONFIG_FS/stp-policy/$source.0/stm_test/channels > $ echo 64 > $CS_DEVS/$source/traceid > $ ./stm_app > Sending 64000 byte blocks of pattern 0 at 0us intervals > Success to map channel(32768~32783) to 0xffffa95fa000 > Sending on channel 32768 > $ dd if=/dev/$ETR of=~/trace.bin.1 > 597+1 records in > 597+1 records out > 305920 bytes (306 kB) copied, 0.399952 s, 765 kB/s > $ ./stm_app > Sending 64000 byte blocks of pattern 0 at 0us intervals > Success to map channel(32768~32783) to 0xffff7e9e2000 > Sending on channel 32768 > $ dd if=/dev/$ETR of=~/trace.bin.2 > 0+0 records in > 0+0 records out > 0 bytes (0 B) copied, 0.0232083 s, 0.0 kB/s > > Note that we don't get any data from the ETR for the second session. > > Also dmesg shows : > > [ 77.520458] coresight-tmc 20800000.etr: TMC-ETR enabled > [ 77.537097] coresight-replicator etr_replicator@20890000: REPLICATOR enabled > [ 77.558828] coresight-replicator main_replicator@208a0000: REPLICATOR enabled > [ 77.581068] coresight-funnel 208c0000.main_funnel: FUNNEL inport 0 enabled > [ 77.602217] coresight-tmc 20840000.etf: TMC-ETF enabled > [ 77.618422] coresight-stm 20860000.stm: STM tracing enabled > [ 139.554252] coresight-stm 20860000.stm: STM tracing disabled > # End of first tracing session > [ 146.351135] coresight-tmc 20800000.etr: TMC read start > [ 146.514486] coresight-tmc 20800000.etr: TMC read end > # Note that the STM is not turned on via stm_generic_link()->coresight_enable() > # and hence none of the components are turned on. > [ 152.479080] coresight-tmc 20800000.etr: TMC read start > [ 152.542632] coresight-tmc 20800000.etr: TMC read end > > This patch fixes the problem by balancing the unlink operation by using > the coresight_disable(), keeping the coresight layer in sync with the > hardware state and thus allowing normal usage of the STM component. > > Fixes: commit 237483aa5cf43 ("coresight: stm: adding driver for CoreSight STM component") > Cc: Pratik Patel > Cc: Greg Kroah-Hartman > Cc: stable@vger.kernel.org # 4.7+ > Acked-by: Mathieu Poirier > Reviewed-by: Chunyan Zhang > Reported-by: Robert Walker > Signed-off-by: Suzuki K Poulose > --- > > Greg, > > Without this patch, the coresight STM IP can only be used for one tracing > session per boot, seriously limiting its usability. When you resend a patch, please tell me what is different from the previous version you sent. I figured it out here, but please do this next time. thanks, greg k-h From mboxrd@z Thu Jan 1 00:00:00 1970 From: gregkh@linuxfoundation.org (Greg KH) Date: Thu, 19 Jan 2017 12:40:37 +0100 Subject: [PATCH] coresight: STM: Balance enable/disable In-Reply-To: <1484589600-21397-1-git-send-email-suzuki.poulose@arm.com> References: <1484589600-21397-1-git-send-email-suzuki.poulose@arm.com> Message-ID: <20170119114037.GR28024@kroah.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jan 16, 2017 at 06:00:00PM +0000, Suzuki K Poulose wrote: > The stm is automatically enabled when an application sets the policy > via ->link() call back by using coresight_enable(), which keeps the > refcount of the current users of the STM. However, the unlink() callback > issues stm_disable() directly, which leaves the STM turned off, without > the coresight layer knowing about it. This prevents any further uses > of the STM hardware as the coresight layer still thinks the STM is > turned on and doesn't enable the hardware when required. Even manually > enabling the STM via sysfs can't really enable the hw. > > e.g, > > $ echo 1 > $CS_DEVS/$ETR/enable_sink > $ mkdir -p $CONFIG_FS/stp-policy/$source.0/stm_test/ > $ echo 32768 65535 > $CONFIG_FS/stp-policy/$source.0/stm_test/channels > $ echo 64 > $CS_DEVS/$source/traceid > $ ./stm_app > Sending 64000 byte blocks of pattern 0 at 0us intervals > Success to map channel(32768~32783) to 0xffffa95fa000 > Sending on channel 32768 > $ dd if=/dev/$ETR of=~/trace.bin.1 > 597+1 records in > 597+1 records out > 305920 bytes (306 kB) copied, 0.399952 s, 765 kB/s > $ ./stm_app > Sending 64000 byte blocks of pattern 0 at 0us intervals > Success to map channel(32768~32783) to 0xffff7e9e2000 > Sending on channel 32768 > $ dd if=/dev/$ETR of=~/trace.bin.2 > 0+0 records in > 0+0 records out > 0 bytes (0 B) copied, 0.0232083 s, 0.0 kB/s > > Note that we don't get any data from the ETR for the second session. > > Also dmesg shows : > > [ 77.520458] coresight-tmc 20800000.etr: TMC-ETR enabled > [ 77.537097] coresight-replicator etr_replicator at 20890000: REPLICATOR enabled > [ 77.558828] coresight-replicator main_replicator at 208a0000: REPLICATOR enabled > [ 77.581068] coresight-funnel 208c0000.main_funnel: FUNNEL inport 0 enabled > [ 77.602217] coresight-tmc 20840000.etf: TMC-ETF enabled > [ 77.618422] coresight-stm 20860000.stm: STM tracing enabled > [ 139.554252] coresight-stm 20860000.stm: STM tracing disabled > # End of first tracing session > [ 146.351135] coresight-tmc 20800000.etr: TMC read start > [ 146.514486] coresight-tmc 20800000.etr: TMC read end > # Note that the STM is not turned on via stm_generic_link()->coresight_enable() > # and hence none of the components are turned on. > [ 152.479080] coresight-tmc 20800000.etr: TMC read start > [ 152.542632] coresight-tmc 20800000.etr: TMC read end > > This patch fixes the problem by balancing the unlink operation by using > the coresight_disable(), keeping the coresight layer in sync with the > hardware state and thus allowing normal usage of the STM component. > > Fixes: commit 237483aa5cf43 ("coresight: stm: adding driver for CoreSight STM component") > Cc: Pratik Patel > Cc: Greg Kroah-Hartman > Cc: stable at vger.kernel.org # 4.7+ > Acked-by: Mathieu Poirier > Reviewed-by: Chunyan Zhang > Reported-by: Robert Walker > Signed-off-by: Suzuki K Poulose > --- > > Greg, > > Without this patch, the coresight STM IP can only be used for one tracing > session per boot, seriously limiting its usability. When you resend a patch, please tell me what is different from the previous version you sent. I figured it out here, but please do this next time. thanks, greg k-h