intel_th: msu: Introduce buffer interface

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Introduces a concept of external buffers, which is a mechanism for creating
trace sinks that would receive trace data from MSC buffers and transfer it
elsewhere.

A external buffer can implement its own window allocation/deallocation if
it has to. It must provide a callback that's used to notify it when a
window fills up, so that it can then start a DMA transaction from that
window 'elsewhere'. This window remains in a 'locked' state and won't be
used for storing new trace data until the buffer 'unlocks' it with a
provided API call, at which point the window can be used again for storing
trace data.

This relies on a functional "last block" interrupt, so not all versions of
Trace Hub can use this feature, which does not reflect on existing users.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190705141425.19894-2-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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This commit is contained in:

Alexander Shishkin 2019-07-05 17:14:21 +03:00 • committed by Greg Kroah-Hartman

parent db4ad308a5

commit 615c164da0

5 changed files with 461 additions and 30 deletions

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3

Documentation/ABI/testing/sysfs-bus-intel_th-devices-msc

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MAINTAINERS

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drivers/hwtracing/intel_th/msu.c

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drivers/hwtracing/intel_th/msu.h

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include/linux/intel_th.h

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