USR1
usr1 = imx_uart_readl(sport, USR1);
imx_uart_writel(sport, USR1_AGTIM, USR1);
imx_uart_writel(sport, USR1_DTRD, USR1);
imx_uart_writel(sport, USR1_AWAKE, USR1);
usr1 = imx_uart_readl(sport, USR1);
imx_uart_writel(sport, USR1_FRAMERR, USR1);
imx_uart_writel(sport, USR1_PARITYERR, USR1);
imx_uart_writel(sport, USR1_RTSD | USR1_DTRD, USR1);
status = imx_uart_readl(sport, USR1);
usr1 = imx_uart_readl(sport, USR1);
imx_uart_writel(sport, USR1_AWAKE, USR1);
imx_uart_writel(sport, USR1_RTSD, USR1);
imx_uart_writel(sport, USR1_RTSD, USR1);
usr1 = imx_uart_readl(sport, USR1) & USR1_RTSS;
unsigned usr1 = imx_uart_readl(sport, USR1);
P_SIGNUM(USR1);