tree 9121bd92b12914638f9d03d7aab4cbba8d52429f
parent 4a0e8ca322d2a5ec9bdd9409cb02d4c08a07bef6
author Alistair Francis <alistair.francis@wdc.com> 1723683448 +1000
committer Alistair Francis <alistair.francis@wdc.com> 1730251328 +1000

hw/char: sifive_uart: Print uart characters async

The current approach of using qemu_chr_fe_write() and ignoring the
return values results in dropped characters [1].

Let's update the SiFive UART to use a async sifive_uart_xmit() function
to transmit the characters and apply back pressure to the guest with
the SIFIVE_UART_TXFIFO_FULL status.

This should avoid dropped characters and more realisticly model the
hardware.

1: https://gitlab.com/qemu-project/qemu/-/issues/2114

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20240910045419.1252277-3-alistair.francis@wdc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>