dmaengine: dw-axi-dmac: support parallel memory <--> peripheral transfers

From: Pandith N <redacted>

Added support for multiple DMA_MEM_TO_DEV, DMA_DEV_TO_MEM transfers in
parallel. Peripherals can use DMA for both transmit and receive
operations in parallel.

To setup DMA handshaking, the peripheral source number to be programmed
in respective channel select slot of AXIDMA_CTRL_DMA_HS_SEL. No need to
check for free slot in dw_axi_dma_set_hw_channel().
The channel slot used in AXIDMA_CTRL_DMA_HS_SEL needs to be set in
src_per/dst_per of CHx_CFG register.

The changes are validated with parallel SPI transmit and receive
transfers in dma mode.

Pandith N (1):
  dmaengine: dw-axi-dmac: support parallel memory <--> peripheral
    transfers

 .../dma/dw-axi-dmac/dw-axi-dmac-platform.c    | 56 +++++++++----------
 drivers/dma/dw-axi-dmac/dw-axi-dmac.h         |  4 ++
 2 files changed, 29 insertions(+), 31 deletions(-)

-- 
2.17.1