Forward the offload's sync_id to the register map, by defining an
additional AXI stream interface between the offload and axi_spi_engine.
The last sync_id of the offload module can read out from the
register 0x00C4. It also can generate and interrupt if the irq mask is
configured accordingly.
SPI Engine is a highly flexible and powerful SPI controller framework. It
consist out of multiple sub-modules which communicate over well defined
interfaces. This allows a high degree of flexibility and re-usability while
at the same time staying highly customizable and easily extensible.
Currently included are four components:
* SPI Engine execution module: The excution module is responsible for
handling the low-level physical interface SPI logic.
* SPI Engine AXI interface module: The AXI interface module allows
memory mapped acccess to a SPI bus control stream and can be used to
implement a software driver that controls the SPI bus.
* SPI Engine offload module: The offload module allows to store a
predefined SPI Engine command and data stream which will be send out
when a external trigger signal is asserted.
* SPI Engine interconnect module: The interconnect module allows to
combine multiple control streams into a single stream giving multiple
control modules access to a execution module.
For more information see: http://wiki.analog.com/resources/fpga/peripherals/spi_engine
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>