Suzuki K Poulose 4474f4c40a coresight: STM: Balance enable/disable ... 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 237483aa5c ("coresight: stm: adding driver for CoreSight STM component") Cc: Pratik Patel <pratikp@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: stable@vger.kernel.org # 4.7+ Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org> Reviewed-by: Chunyan Zhang <zhang.chunyan@linaro.org> Reported-by: Robert Walker <robert.walker@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2017-01-19 12:42:25 +01:00
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coresight	coresight: STM: Balance enable/disable	2017-01-19 12:42:25 +01:00
intel_th	This release has a few updates:	2016-12-15 13:49:34 -08:00
stm	This release has a few updates:	2016-12-15 13:49:34 -08:00