<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/drivers/hwtracing, branch v4.9.95</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>coresight: tmc: Configure DMA mask appropriately</title>
<updated>2018-04-13T17:48:26+00:00</updated>
<author>
<name>Robin Murphy</name>
<email>robin.murphy@arm.com</email>
</author>
<published>2017-06-05T20:15:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=9606743ca7f8f45b0e589e5ff8dd93a3e49dcdd1'/>
<id>9606743ca7f8f45b0e589e5ff8dd93a3e49dcdd1</id>
<content type='text'>
[ Upstream commit a3959c50b02f57df4c4e4f14f632220f1c0b1f79 ]

Before making any DMA API calls, the ETR driver should really be setting
its masks to ensure that DMA is possible. Especially since it can
address more than the 32-bit default mask set by the AMBA bus code.

Signed-off-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Tested-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit a3959c50b02f57df4c4e4f14f632220f1c0b1f79 ]

Before making any DMA API calls, the ETR driver should really be setting
its masks to ensure that DMA is possible. Especially since it can
address more than the 32-bit default mask set by the AMBA bus code.

Signed-off-by: Robin Murphy &lt;robin.murphy@arm.com&gt;
Tested-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>coresight: Fix reference count for software sources</title>
<updated>2018-04-13T17:48:25+00:00</updated>
<author>
<name>Suzuki K Poulose</name>
<email>suzuki.poulose@arm.com</email>
</author>
<published>2017-06-05T20:15:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=41830b8672a801adb74486d37fee4c35c9ca42b2'/>
<id>41830b8672a801adb74486d37fee4c35c9ca42b2</id>
<content type='text'>
[ Upstream commit 022aa1a81b778789ee7cf3124595854276a0330d ]

For software sources (i.e STM), there could be multiple agents
generating the trace data, unlike the ETMs. So we need to
properly do the accounting for the active number of users
to disable the device when the last user goes away. Right
now, the reference counting is broken for sources as we skip
the actions when we detect that the source is enabled.

This patch fixes the problem by adding the refcounting for
software sources, even when they are enabled.

Cc: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Reported-by: Robert Walker &lt;robert.walker@arm.com&gt;
Signed-off-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 022aa1a81b778789ee7cf3124595854276a0330d ]

For software sources (i.e STM), there could be multiple agents
generating the trace data, unlike the ETMs. So we need to
properly do the accounting for the active number of users
to disable the device when the last user goes away. Right
now, the reference counting is broken for sources as we skip
the actions when we detect that the source is enabled.

This patch fixes the problem by adding the refcounting for
software sources, even when they are enabled.

Cc: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Reported-by: Robert Walker &lt;robert.walker@arm.com&gt;
Signed-off-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>coresight: Fix disabling of CoreSight TPIU</title>
<updated>2018-03-24T10:00:25+00:00</updated>
<author>
<name>Robert Walker</name>
<email>robert.walker@arm.com</email>
</author>
<published>2017-12-18T18:05:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=ba936f25f95378142e854cc70e35375a452815a9'/>
<id>ba936f25f95378142e854cc70e35375a452815a9</id>
<content type='text'>
[ Upstream commit 11595db8e17faaa05fadc25746c870e31276962f ]

The CoreSight TPIU should be disabled when tracing to other sinks to allow
them to operate at full bandwidth.

This patch fixes tpiu_disable_hw() to correctly disable the TPIU by
configuring the TPIU to stop on flush, initiating a manual flush, waiting
for the flush to complete and then waits for the TPIU to indicate it has
stopped.

Signed-off-by: Robert Walker &lt;robert.walker@arm.com&gt;
Tested-by: Mike Leach &lt;mike.leach@linaro.org&gt;
Signed-off-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 11595db8e17faaa05fadc25746c870e31276962f ]

The CoreSight TPIU should be disabled when tracing to other sinks to allow
them to operate at full bandwidth.

This patch fixes tpiu_disable_hw() to correctly disable the TPIU by
configuring the TPIU to stop on flush, initiating a manual flush, waiting
for the flush to complete and then waits for the TPIU to indicate it has
stopped.

Signed-off-by: Robert Walker &lt;robert.walker@arm.com&gt;
Tested-by: Mike Leach &lt;mike.leach@linaro.org&gt;
Signed-off-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>coresight: Fixes coresight DT parse to get correct output port ID.</title>
<updated>2018-03-22T08:17:49+00:00</updated>
<author>
<name>Mike Leach</name>
<email>mike.leach@linaro.org</email>
</author>
<published>2017-03-27T17:09:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=b1a579996f63e2b6a88e8360953884bb6f965ced'/>
<id>b1a579996f63e2b6a88e8360953884bb6f965ced</id>
<content type='text'>
[ Upstream commit eeedc5421dd3b51de73e6106405c5c77f920f281 ]

Corrected to get the port numbering to allow programmable replicator driver
to operate correctly.

By convention, CoreSight devices number ports, not endpoints in
the .dts files:-

port {
     reg&lt;N&gt;
     endpoint {
     }
}

Existing code read endpoint number - always 0x0, rather than the correct
port number.

Signed-off-by: Mike Leach &lt;mike.leach@linaro.org&gt;
Signed-off-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit eeedc5421dd3b51de73e6106405c5c77f920f281 ]

Corrected to get the port numbering to allow programmable replicator driver
to operate correctly.

By convention, CoreSight devices number ports, not endpoints in
the .dts files:-

port {
     reg&lt;N&gt;
     endpoint {
     }
}

Existing code read endpoint number - always 0x0, rather than the correct
port number.

Signed-off-by: Mike Leach &lt;mike.leach@linaro.org&gt;
Signed-off-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>intel_th: pci: Add Gemini Lake support</title>
<updated>2017-12-20T09:07:22+00:00</updated>
<author>
<name>Alexander Shishkin</name>
<email>alexander.shishkin@linux.intel.com</email>
</author>
<published>2016-06-30T13:10:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=18b39b61b2c66556396f8584f0769f221d3383f6'/>
<id>18b39b61b2c66556396f8584f0769f221d3383f6</id>
<content type='text'>
[ Upstream commit 340837f985c2cb87ca0868d4aa9ce42b0fab3a21 ]

This adds Intel(R) Trace Hub PCI ID for Gemini Lake SOC.

Signed-off-by: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 340837f985c2cb87ca0868d4aa9ce42b0fab3a21 ]

This adds Intel(R) Trace Hub PCI ID for Gemini Lake SOC.

Signed-off-by: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Signed-off-by: Sasha Levin &lt;alexander.levin@verizon.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>stm class: Fix a use-after-free</title>
<updated>2017-10-12T09:51:24+00:00</updated>
<author>
<name>Alexander Shishkin</name>
<email>alexander.shishkin@linux.intel.com</email>
</author>
<published>2017-09-19T15:47:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3ff8bc813b1301ee1395b4629b5136559e3fc6ba'/>
<id>3ff8bc813b1301ee1395b4629b5136559e3fc6ba</id>
<content type='text'>
commit fd085bb1766d6a598f53af2308374a546a49775a upstream.

For reasons unknown, the stm_source removal path uses device_destroy()
to kill the underlying device object. Because device_destroy() uses
devt to look for the device to destroy and the fact that stm_source
devices don't have one (or all have the same one), it just picks the
first device in the class, which may well be the wrong one.

That is, loading stm_console and stm_heartbeat and then removing both
will die in dereferencing a freed object.

Since this should have been device_unregister() in the first place,
use it instead of device_destroy().

Signed-off-by: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Fixes: 7bd1d4093c2 ("stm class: Introduce an abstraction for System Trace Module devices")
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit fd085bb1766d6a598f53af2308374a546a49775a upstream.

For reasons unknown, the stm_source removal path uses device_destroy()
to kill the underlying device object. Because device_destroy() uses
devt to look for the device to destroy and the fact that stm_source
devices don't have one (or all have the same one), it just picks the
first device in the class, which may well be the wrong one.

That is, loading stm_console and stm_heartbeat and then removing both
will die in dereferencing a freed object.

Since this should have been device_unregister() in the first place,
use it instead of device_destroy().

Signed-off-by: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Fixes: 7bd1d4093c2 ("stm class: Introduce an abstraction for System Trace Module devices")
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>intel_th: pci: Add Cannon Lake PCH-LP support</title>
<updated>2017-09-09T15:39:39+00:00</updated>
<author>
<name>Alexander Shishkin</name>
<email>alexander.shishkin@linux.intel.com</email>
</author>
<published>2016-06-30T13:11:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d8b992d93555af94d31264be3fbe73aca1945947'/>
<id>d8b992d93555af94d31264be3fbe73aca1945947</id>
<content type='text'>
commit efb3669e14fe17d0ec4ecf57d0365039fe726f59 upstream.

This adds Intel(R) Trace Hub PCI ID for Cannon Lake PCH-LP.

Signed-off-by: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit efb3669e14fe17d0ec4ecf57d0365039fe726f59 upstream.

This adds Intel(R) Trace Hub PCI ID for Cannon Lake PCH-LP.

Signed-off-by: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>intel_th: pci: Add Cannon Lake PCH-H support</title>
<updated>2017-09-09T15:39:39+00:00</updated>
<author>
<name>Alexander Shishkin</name>
<email>alexander.shishkin@linux.intel.com</email>
</author>
<published>2016-06-30T13:11:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a22d561178ee2e96ca4bf519669d533144e7145c'/>
<id>a22d561178ee2e96ca4bf519669d533144e7145c</id>
<content type='text'>
commit 84331e1390b6378a5129a3678c87a42c6f697d29 upstream.

This adds Intel(R) Trace Hub PCI ID for Cannon Lake PCH-H.

Signed-off-by: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 84331e1390b6378a5129a3678c87a42c6f697d29 upstream.

This adds Intel(R) Trace Hub PCI ID for Cannon Lake PCH-H.

Signed-off-by: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>intel_th: Don't leak module refcount on failure to activate</title>
<updated>2017-03-30T07:41:27+00:00</updated>
<author>
<name>Alexander Shishkin</name>
<email>alexander.shishkin@linux.intel.com</email>
</author>
<published>2017-02-24T14:04:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=3076066bb5076411627f9dffd9d59ff2497f7eac'/>
<id>3076066bb5076411627f9dffd9d59ff2497f7eac</id>
<content type='text'>
commit e609ccef5222c73b46b322be7d3796d60bff353d upstream.

Output 'activation' may fail for the reasons of the output driver,
for example, if msc's buffer is not allocated. We forget, however,
to drop the module reference in this case. So each attempt at
activation in this case leaks a reference, preventing the module
from ever unloading.

This patch adds the missing module_put() in the activation error
path.

Signed-off-by: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e609ccef5222c73b46b322be7d3796d60bff353d upstream.

Output 'activation' may fail for the reasons of the output driver,
for example, if msc's buffer is not allocated. We forget, however,
to drop the module reference in this case. So each attempt at
activation in this case leaks a reference, preventing the module
from ever unloading.

This patch adds the missing module_put() in the activation error
path.

Signed-off-by: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>coresight: STM: Balance enable/disable</title>
<updated>2017-03-12T05:41:42+00:00</updated>
<author>
<name>Suzuki K Poulose</name>
<email>suzuki.poulose@arm.com</email>
</author>
<published>2017-01-16T18:00:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=59cd503c8cfd3f69f8126165b274860bbbd058db'/>
<id>59cd503c8cfd3f69f8126165b274860bbbd058db</id>
<content type='text'>
commit 4474f4c40a9c607c7317e686b23619b7b768004f upstream.

The stm is automatically enabled when an application sets the policy
via -&gt;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 &gt; $CS_DEVS/$ETR/enable_sink
 $ mkdir -p $CONFIG_FS/stp-policy/$source.0/stm_test/
 $ echo 32768 65535 &gt; $CONFIG_FS/stp-policy/$source.0/stm_test/channels
 $ echo 64 &gt; $CS_DEVS/$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()-&gt;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 &lt;pratikp@codeaurora.org&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Acked-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Reviewed-by: Chunyan Zhang &lt;zhang.chunyan@linaro.org&gt;
Reported-by: Robert Walker &lt;robert.walker@arm.com&gt;
Signed-off-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 4474f4c40a9c607c7317e686b23619b7b768004f upstream.

The stm is automatically enabled when an application sets the policy
via -&gt;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 &gt; $CS_DEVS/$ETR/enable_sink
 $ mkdir -p $CONFIG_FS/stp-policy/$source.0/stm_test/
 $ echo 32768 65535 &gt; $CONFIG_FS/stp-policy/$source.0/stm_test/channels
 $ echo 64 &gt; $CS_DEVS/$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()-&gt;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 &lt;pratikp@codeaurora.org&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Acked-by: Mathieu Poirier &lt;mathieu.poirier@linaro.org&gt;
Reviewed-by: Chunyan Zhang &lt;zhang.chunyan@linaro.org&gt;
Reported-by: Robert Walker &lt;robert.walker@arm.com&gt;
Signed-off-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

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