From: Mingrui Ren
mainline inclusion
from mainline-v5.11-rc1
commit aef1b6a27970607721a618a0b990716ca8dbbf9
category: bugfix
issue: #I3ZXZF
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
-------------------------------------------------
As described in Documentation, poll_init() is called by kgdb to initialize
hardware which supports both poll_put_char() and poll_get_char().
It's necessary to enable TXEN bit, otherwise, it will cause hardware fault
and kernel panic when calling imx_poll_put_char().
Generally, if use /dev/ttymxc0 as kgdb console as well as system
console, ttymxc0 is initialized early by system console which does enable
TXEN bit.But when use /dev/ttymxc1 as kgbd console, ttymxc1 is only
initialized by imx_poll_init() cannot enable the TXEN bit, which will
cause kernel panic.
Signed-off-by: Mingrui Ren
Link: https://lore.kernel.org/r/20201202072543.151-1-972931182@qq.com
Signed-off-by: Greg Kroah-Hartman
Signed-off-by: Lu Jialin
Reviewed-by: Xiu Jianfeng
Signed-off-by: Chen Jun
Signed-off-by: Yu Changchun
---
drivers/tty/serial/imx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index cacf7266a262..a66301b3b33d 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1881,7 +1881,7 @@ static int imx_uart_poll_init(struct uart_port *port)
ucr1 |= UCR1_UARTEN;
ucr1 &= ~(UCR1_TRDYEN | UCR1_RTSDEN | UCR1_RRDYEN);
- ucr2 |= UCR2_RXEN;
+ ucr2 |= UCR2_RXEN | UCR2_TXEN;
ucr2 &= ~UCR2_ATEN;
imx_uart_writel(sport, ucr1, UCR1);
--
2.22.0
