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author | Erwan Le Ray <erwan.leray@foss.st.com> | 2021-03-04 17:22:58 +0100 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-10 09:34:10 +0100 |
commit | f264c6f6aece81a9f8fbdf912b20bd3feb476a7a (patch) | |
tree | c946c89f35db0ae80eb75482df7583920d5105bc /drivers/tty/serial/stm32-usart.c | |
parent | f4518a8a75f5be1a121b0c95ad9c6b1eb27d920e (diff) | |
download | linux-stable-f264c6f6aece81a9f8fbdf912b20bd3feb476a7a.tar.gz linux-stable-f264c6f6aece81a9f8fbdf912b20bd3feb476a7a.tar.bz2 linux-stable-f264c6f6aece81a9f8fbdf912b20bd3feb476a7a.zip |
serial: stm32: fix incorrect characters on console
Incorrect characters are observed on console during boot. This issue occurs
when init/main.c is modifying termios settings to open /dev/console on the
rootfs.
This patch adds a waiting loop in set_termios to wait for TX shift register
empty (and TX FIFO if any) before stopping serial port.
Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-4-erwan.leray@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/stm32-usart.c')
-rw-r--r-- | drivers/tty/serial/stm32-usart.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index c6ca8f964c69..eae54b8cf5e2 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -738,8 +738,9 @@ static void stm32_usart_set_termios(struct uart_port *port, unsigned int baud, bits; u32 usartdiv, mantissa, fraction, oversampling; tcflag_t cflag = termios->c_cflag; - u32 cr1, cr2, cr3; + u32 cr1, cr2, cr3, isr; unsigned long flags; + int ret; if (!stm32_port->hw_flow_control) cflag &= ~CRTSCTS; @@ -748,6 +749,15 @@ static void stm32_usart_set_termios(struct uart_port *port, spin_lock_irqsave(&port->lock, flags); + ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, + isr, + (isr & USART_SR_TC), + 10, 100000); + + /* Send the TC error message only when ISR_TC is not set. */ + if (ret) + dev_err(port->dev, "Transmission is not complete\n"); + /* Stop serial port and reset value */ writel_relaxed(0, port->membase + ofs->cr1); |