PORT_CMD_START
if ((tmp & (PORT_CMD_START | PORT_CMD_LIST_ON)) == 0)
tmp &= ~PORT_CMD_START;
sunxi_setbits(port_mmio + PORT_CMD, PORT_CMD_START);
tmp |= PORT_CMD_START;
if ((tmp & (PORT_CMD_START | PORT_CMD_LIST_ON)) == 0)
tmp &= ~PORT_CMD_START;
writel(tmp | PORT_CMD_START, port->mmio + PORT_CMD);
writel(tmp & ~PORT_CMD_START, port->mmio + PORT_CMD);
return (((tmp & PORT_CMD_START) == PORT_CMD_START));