The watermark bits are set in the interrupt pending register according
to the configuration of txcnt and rxcnt in the txctrl and rxctrl
registers.
Since the UART TX does not implement a FIFO, the txwm bit is set as long
as the TX watermark level is greater than zero.
Signed-off-by: Nathaniel Graff <nathaniel.graff@sifive.com>
Reviewed-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
QEMU model of the UART on the SiFive E300 and U500 series SOCs.
BBL supports the SiFive UART for early console access via the SBI
(Supervisor Binary Interface) and the linux kernel SBI console.
The SiFive UART implements the pre qom legacy interface consistent
with the 16550a UART in 'hw/char/serial.c'.
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Stefan O'Rear <sorear2@gmail.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
Nathaniel Graff
Michael Clark