lkml.org 
[lkml]   [2022]   [Nov]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v5 2/3] tty: serial: use uart_port_tx() helper
Date
From: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>

Hi Jiri,

> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index bd07f79a2df9..a6b4d30c5888 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -824,30 +824,14 @@ static void atmel_rx_chars(struct uart_port *port)
> */
> static void atmel_tx_chars(struct uart_port *port)
> {
> - struct circ_buf *xmit = &port->state->xmit;
> struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> + bool pending;
> + u8 ch;
>
> - if (port->x_char &&
> - (atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY)) {
> - atmel_uart_write_char(port, port->x_char);
> - port->icount.tx++;
> - port->x_char = 0;
> - }
> - if (uart_circ_empty(xmit) || uart_tx_stopped(port))
> - return;
> -
> - while (atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY) {
> - atmel_uart_write_char(port, xmit->buf[xmit->tail]);
> - xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
> - port->icount.tx++;
> - if (uart_circ_empty(xmit))
> - break;
> - }
> -
> - if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
> - uart_write_wakeup(port);
> -
> - if (!uart_circ_empty(xmit)) {
> + pending = uart_port_tx(port, ch,
> + atmel_uart_readl(port, ATMEL_US_CSR) & ATMEL_US_TXRDY,
> + atmel_uart_write_char(port, ch));
> + if (pending) {
> /* we still have characters to transmit, so we should continue
> * transmitting them when TX is ready, regardless of
> * mode or duplexity

This will break serial output for the userspace on my board
(arch/arm/boot/dts/lan966x-kontron-kswitch-d10-mmt*dts). The uart_port_tx()
helper will call __port->ops->stop_tx(__port) if uart_circ_chars_pending()
returns 0. But the code above, doesn't do that. In fact, removing the
stop_tx() call in the helper macro, will fix the console output.

Any ideas how to fix that?

-michael

\
 
 \ /
  Last update: 2022-11-21 21:28    [W:0.679 / U:0.192 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site