Driver for Cadence HPNFC NAND flash controller.
HW DMA interface
Page write and page read operations are executed in Command DMA mode.
Commands are defined by DMA descriptors.
In CDMA mode controller own DMA engine is used (Master DMA mode).
Other operations defined by nand_op_instr are executed in "Generic" mode.
In that mode data can be transferred only in by Slave DMA interface.
Slave DMA interface can be connected directly to AXI or to an external
DMA engine.