• Alexander Shishkin's avatar
    stm class: Introduce an abstraction for System Trace Module devices · 7bd1d409
    Alexander Shishkin authored
    A System Trace Module (STM) is a device exporting data in System Trace
    Protocol (STP) format as defined by MIPI STP standards. Examples of such
    devices are Intel(R) Trace Hub and Coresight STM.
    This abstraction provides a unified interface for software trace sources
    to send their data over an STM device to a debug host. In order to do
    that, such a trace source needs to be assigned a pair of master/channel
    identifiers that all the data from this source will be tagged with. The
    STP decoder on the debug host side will use these master/channel tags to
    distinguish different trace streams from one another inside one STP
    This abstraction provides a configfs-based policy management mechanism
    for dynamic allocation of these master/channel pairs based on trace
    source-supplied string identifier. It has the flexibility of being
    defined at runtime and at the same time (provided that the policy
    definition is aligned with the decoding end) consistency.
    For userspace trace sources, this abstraction provides write()-based and
    mmap()-based (if the underlying stm device allows this) output mechanism.
    For kernel-side trace sources, we provide "stm_source" device class that
    can be connected to an stm device at run time.
    Cc: linux-api@vger.kernel.org
    Reviewed-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
    Signed-off-by: default avatarAlexander Shishkin <alexander.shishkin@linux.intel.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Makefile 4.79 KB