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Since the ETR could be driven either by SYSFS or by perf, it becomes complicated how we deal with the buffers used for each of these modes. The ETR driver cannot simply free the current attached buffer without knowing the provider (i.e, sysfs vs perf). To solve this issue, we provide: 1) the driver-mode specific etr buffer to be retained in the drvdata 2) the etr_buf for a session should be passed on when enabling the hardware, which will be stored in drvdata->etr_buf. This will be replaced (not free'd) as soon as the hardware is disabled, after necessary sync operation. The advantages of this are : 1) The common code path doesn't need to worry about how to dispose an existing buffer, if it is about to start a new session with a different buffer, possibly in a different mode. 2) The driver mode can control its buffers and can get access to the saved session even when the hardware is operating in a different mode. (e.g, we can still access a trace buffer from a sysfs mode even if the etr is now used in perf mode, without disrupting the current session.) Towards this, we introduce a sysfs specific data which will hold the etr_buf used for sysfs mode of operation, controlled solely by the sysfs mode handling code. Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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