• Suzuki K Poulose's avatar
    coresight: Add generic TMC sg table framework · 99443ea1
    Suzuki K Poulose authored
    This patch introduces a generic sg table data structure and
    associated operations. An SG table can be used to map a set
    of Data pages where the trace data could be stored by the TMC
    ETR. The information about the data pages could be stored in
    different formats, depending on the type of the underlying
    SG mechanism (e.g, TMC ETR SG vs Coresight CATU). The generic
    structure provides book keeping of the pages used for the data
    as well as the table contents. The table should be filled by
    the user of the infrastructure.
    
    A table can be created by specifying the number of data pages
    as well as the number of table pages required to hold the
    pointers, where the latter could be different for different
    types of tables. The pages are mapped in the appropriate dma
    data direction mode (i.e, DMA_TO_DEVICE for table pages
    and DMA_FROM_DEVICE for data pages).  The framework can optionally
    accept a set of allocated data pages (e.g, perf ring buffer) and
    map them accordingly. The table and data pages are vmap'ed to allow
    easier access by the drivers. The framework also provides helpers to
    sync the data written to the pages with appropriate directions.
    
    This will be later used by the TMC ETR SG unit and CATU.
    
    Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
    Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
    Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    99443ea1
coresight-tmc-etr.c 15.1 KB