serial: qcom-geni: Keep FIFO RX active during console TX

The GENI main sequencer handles console TX while the secondary sequencer
handles FIFO RX. Before nbcon, the legacy console writer disabled both
interrupt domains while it performed a long polled M-side transfer. This
left the small S-side FIFO unserviced, allowing console input to overrun
and be lost.

The nbcon conversion replaces IRQ masking with the UART port lock, but a
threaded console write still prevents the RX handler from draining the
FIFO. Keep S-side RX enabled independently of M-side TX and drain it
while refilling each bounded console command. This preserves interactive
input during console output.

Atomic output masks only M-side TX state, leaving FIFO RX handling
independent. The threaded writer can also detect a SysRq character while
it drains RX, so defer delivery until device_unlock() drops the UART port
lock, as the existing IRQ path does with uart_unlock_and_check_sysrq().

Assisted-by: OpenCode:GPT-5.5
Signed-off-by: Bjorn Andersson <bjorn.andersson@oss.qualcomm.com>
Link: https://patch.msgid.link/20260729-qcom-geni-nbcon-v1-2-3053b96465ed@oss.qualcomm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions