UCR2_SRST
ucr2 |= UCR2_SRST | UCR2_IRTS;
imx_uart_writel(sport, sport->saved_reg[1] | UCR2_SRST, UCR2);
imx_uart_writel(sport, ucr2 & ~UCR2_SRST, UCR2);
while (!(imx_uart_readl(sport, UCR2) & UCR2_SRST) && (--i > 0))