UART011_CR_RXE is set in pl011_startup() during normal initialization, and cleared by pl011_disable_uart() during port shutdown. You can use a none-console port in poll mode like kgdboc does with tty_find_polling_driver() after a port shutdown. But pl011_startup() is not called in tty_find_polling_driver(). So you need to set UART011_CR_RXE to reenable receive function. Not sure setting UART011_CR_RXE in pl011_set_termios() is a good idea through. Signed-off-by: Hongyu Xie <xiehongyu1@xxxxxxxxxx> --- drivers/tty/serial/amba-pl011.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index d8c2f3455eeb..c5c3f4674459 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2166,6 +2166,13 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios, * ----------^----------^----------^----------^----- */ pl011_write_lcr_h(uap, lcr_h); + + /* + * Receive was disabled by pl011_disable_uart during shutdown. + * Need to reenable receive if you need to use a tty_driver + * returns from tty_find_polling_driver() after a port shutdown. + */ + old_cr |= UART011_CR_RXE; pl011_write(old_cr, uap, REG_CR); spin_unlock_irqrestore(&port->lock, flags); -- 2.34.1
