UART_TSH
writel(c, port->membase + UART_TSH(port));
writel(ch, port->membase + UART_TSH(port)),
writel(c, port->membase + UART_TSH(port));
writel(ch, port->membase + UART_TSH(port));
mvuart->pm_regs.tsh = readl(port->membase + UART_TSH(port));
writel(mvuart->pm_regs.tsh, port->membase + UART_TSH(port));