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tty/serial/imx: Enable TXEN bit in imx_poll_init(). 

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 <jiladahe1997@gmail.com>
Link: https://lore.kernel.org/r/20201202072543.151-1-972931182@qq.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zero-sugar-mainline-defconfig
Mingrui Ren 2020-12-02 15:25:43 +08:00 committed by Greg Kroah-Hartman
parent 7af77ba424
commit aef1b6a279
1 changed files with 1 additions and 1 deletions
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2
drivers/tty/serial/imx.c
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@ -1861,7 +1861,7 @@ 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);