From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S941415AbdAJRgu (ORCPT ); Tue, 10 Jan 2017 12:36:50 -0500 Received: from mail-io0-f174.google.com ([209.85.223.174]:34252 "EHLO mail-io0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941134AbdAJRgq (ORCPT ); Tue, 10 Jan 2017 12:36:46 -0500 Date: Tue, 10 Jan 2017 10:36:37 -0700 From: Mathieu Poirier To: Suzuki K Poulose Cc: zhang.chunyan@linaro.org, pratikp@codeaurora.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, gregkh@linuxfoundation.org, stable@vger.kernel.org Subject: Re: [PATCH] coresight: STM: Balance enable/disable Message-ID: <20170110173637.GA12100@linaro.org> References: <1484047315-14407-1-git-send-email-suzuki.poulose@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1484047315-14407-1-git-send-email-suzuki.poulose@arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 10, 2017 at 11:21:55AM +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 issue an stm_enable(). 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 balances the unlink operation by using the coresight_disable(), > keeping the coresight layer in sync with the hardware state. > > Fixes: commit 237483aa5cf43 ("coresight: stm: adding driver for CoreSight STM component") > Cc: Pratik Patel > Cc: Mathieu Poirier > Cc: Chunyan Zhang > Cc: Greg Kroah-Hartman > Cc: stable@vger.kernel.org # 4.7+ > Reported-by: Robert Walker > Signed-off-by: Suzuki K Poulose > --- > drivers/hwtracing/coresight/coresight-stm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c > index 3524452..57b7330 100644 > --- a/drivers/hwtracing/coresight/coresight-stm.c > +++ b/drivers/hwtracing/coresight/coresight-stm.c > @@ -356,7 +356,7 @@ static void stm_generic_unlink(struct stm_data *stm_data, > if (!drvdata || !drvdata->csdev) > return; > > - stm_disable(drvdata->csdev, NULL); > + coresight_disable(drvdata->csdev); This looks valid to me. Chunyan, any reason to use stm_disable() directly rather than calling it as part of the device OPS in coresight_disable()? Thanks, Mathieu > } > > static phys_addr_t > -- > 2.7.4 > From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathieu.poirier@linaro.org (Mathieu Poirier) Date: Tue, 10 Jan 2017 10:36:37 -0700 Subject: [PATCH] coresight: STM: Balance enable/disable In-Reply-To: <1484047315-14407-1-git-send-email-suzuki.poulose@arm.com> References: <1484047315-14407-1-git-send-email-suzuki.poulose@arm.com> Message-ID: <20170110173637.GA12100@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Jan 10, 2017 at 11:21:55AM +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 issue an stm_enable(). 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 balances the unlink operation by using the coresight_disable(), > keeping the coresight layer in sync with the hardware state. > > Fixes: commit 237483aa5cf43 ("coresight: stm: adding driver for CoreSight STM component") > Cc: Pratik Patel > Cc: Mathieu Poirier > Cc: Chunyan Zhang > Cc: Greg Kroah-Hartman > Cc: stable at vger.kernel.org # 4.7+ > Reported-by: Robert Walker > Signed-off-by: Suzuki K Poulose > --- > drivers/hwtracing/coresight/coresight-stm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c > index 3524452..57b7330 100644 > --- a/drivers/hwtracing/coresight/coresight-stm.c > +++ b/drivers/hwtracing/coresight/coresight-stm.c > @@ -356,7 +356,7 @@ static void stm_generic_unlink(struct stm_data *stm_data, > if (!drvdata || !drvdata->csdev) > return; > > - stm_disable(drvdata->csdev, NULL); > + coresight_disable(drvdata->csdev); This looks valid to me. Chunyan, any reason to use stm_disable() directly rather than calling it as part of the device OPS in coresight_disable()? Thanks, Mathieu > } > > static phys_addr_t > -- > 2.7.4 >