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>
* ----------^----------^----------^----------^-----
*/
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);