SDMA_CMD
wrl(pep, SDMA_CMD, SDMA_CMD_TXDH | SDMA_CMD_ERD);
wrl(pep, SDMA_CMD, SDMA_CMD_AR | SDMA_CMD_AT);
while ((rdl(pep, SDMA_CMD) & (SDMA_CMD_AR | SDMA_CMD_AT))
val = rdl(pep, SDMA_CMD);
wrl(pep, SDMA_CMD, val);
val = rdl(pep, SDMA_CMD);