DMA_CHAN_OFFSET
#define ETH0_RX_DMA_ADDR (DMA0_BASE_ADDR + 0 * DMA_CHAN_OFFSET)
#define ETH0_TX_DMA_ADDR (DMA0_BASE_ADDR + 1 * DMA_CHAN_OFFSET)
.end = ETH0_RX_DMA_ADDR + DMA_CHAN_OFFSET - 1,
.end = ETH0_TX_DMA_ADDR + DMA_CHAN_OFFSET - 1,
int offset = channel * DMA_CHAN_SIZE + DMA_CHAN_OFFSET;