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99443ea19e
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: 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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