UART_MCTL_TXFIFOTHRESH_SHIFT  457 drivers/tty/serial/bcm63xx_uart.c 	val |= (port->fifosize / 2) << UART_MCTL_TXFIFOTHRESH_SHIFT;
UART_MCTL_TXFIFOTHRESH_SHIFT   54 include/linux/serial_bcm63xx.h #define UART_MCTL_TXFIFOTHRESH_MASK	(0xf << UART_MCTL_TXFIFOTHRESH_SHIFT)