Commit 6d8c1fca authored May 01, 2023 by Hongyu Xie Committed by Greg Kroah-Hartman May 13, 2023

serial: pl011: set UART011_CR_RXE in pl011_set_termios after port shutdown



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@kylinos.cn>
Link: https://lore.kernel.org/r/20230501070909.1144547-1-xiehongyu1@kylinos.cn


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent cf9aa72d

drivers/tty/serial/amba-pl011.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -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);