[PATCH 1/2] serial: core: introduce uart_port_tx_limited_flags()

[PATCH 1/2] serial: core: introduce uart_port_tx_limited_flags()

[Jonas Gorski]

Analogue to uart_port_tx_flags() introduced in commit 3ee07964d407
("serial: core: introduce uart_port_tx_flags()"), add a _flags variant
for uart_port_tx_limited().

Fixes: d11cc8c3c4b6 ("tty: serial: use uart_port_tx_limited()")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
---
 include/linux/serial_core.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 55b1f3ba48ac..e25e20034a19 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -825,6 +825,24 @@ enum UART_TX_FLAGS {
 			__count--);					      \
 })
 
+/**
+ * uart_port_tx_limited_flags -- transmit helper for uart_port with count limiting with flags
+ * @port: uart port
+ * @ch: variable to store a character to be written to the HW
+ * @flags: %UART_TX_NOSTOP or similar
+ * @count: a limit of characters to send
+ * @tx_ready: can HW accept more data function
+ * @put_char: function to write a character
+ * @tx_done: function to call after the loop is done
+ *
+ * See uart_port_tx_limited() for more details.
+ */
+#define uart_port_tx_limited_flags(port, ch, flags, count, tx_ready, put_char, tx_done) ({ \
+	unsigned int __count = (count);							   \
+	__uart_port_tx(port, ch, flags, tx_ready, put_char, tx_done, __count,		   \
+			__count--);							   \
+})
+
 /**
  * uart_port_tx -- transmit helper for uart_port
  * @port: uart port
-- 
2.34.1

[PATCH 2/2] serial: bcm63xx-uart: fix tx after conversion to uart_port_tx_limited()

[Jonas Gorski]

When bcm63xx-uart was converted to uart_port_tx_limited(), it implicitly
added a call to stop_tx(). This causes garbage to be put out on the
serial console. To fix this, pass UART_TX_NOSTOP in flags, and manually
call stop_tx() ourselves analogue to how a similar issue was fixed in
commit 7be50f2e8f20 ("serial: mxs-auart: fix tx").

Fixes: d11cc8c3c4b6 ("tty: serial: use uart_port_tx_limited()")
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
---
 drivers/tty/serial/bcm63xx_uart.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/bcm63xx_uart.c b/drivers/tty/serial/bcm63xx_uart.c
index a3cefa153456..259fe5895032 100644
--- a/drivers/tty/serial/bcm63xx_uart.c
+++ b/drivers/tty/serial/bcm63xx_uart.c
@@ -309,8 +309,8 @@ static void bcm_uart_do_tx(struct uart_port *port)
 
 	val = bcm_uart_readl(port, UART_MCTL_REG);
 	val = (val & UART_MCTL_TXFIFOFILL_MASK) >> UART_MCTL_TXFIFOFILL_SHIFT;
-
-	pending = uart_port_tx_limited(port, ch, port->fifosize - val,
+	pending = uart_port_tx_limited_flags(port, ch, UART_TX_NOSTOP,
+		port->fifosize - val,
 		true,
 		bcm_uart_writel(port, ch, UART_FIFO_REG),
 		({}));
@@ -321,6 +321,9 @@ static void bcm_uart_do_tx(struct uart_port *port)
 	val = bcm_uart_readl(port, UART_IR_REG);
 	val &= ~UART_TX_INT_MASK;
 	bcm_uart_writel(port, val, UART_IR_REG);
+
+	if (uart_tx_stopped(port))
+		bcm_uart_stop_tx(port);
 }
 
 /*
-- 
2.34.1

Re: [PATCH 2/2] serial: bcm63xx-uart: fix tx after conversion to uart_port_tx_limited()

[Greg Kroah-Hartman]

On Sun, Feb 25, 2024 at 04:14:26PM +0100, Jonas Gorski wrote:
> When bcm63xx-uart was converted to uart_port_tx_limited(), it implicitly
> added a call to stop_tx(). This causes garbage to be put out on the
> serial console. To fix this, pass UART_TX_NOSTOP in flags, and manually
> call stop_tx() ourselves analogue to how a similar issue was fixed in
> commit 7be50f2e8f20 ("serial: mxs-auart: fix tx").
> 
> Fixes: d11cc8c3c4b6 ("tty: serial: use uart_port_tx_limited()")
> Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
> ---
>  drivers/tty/serial/bcm63xx_uart.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/bcm63xx_uart.c b/drivers/tty/serial/bcm63xx_uart.c
> index a3cefa153456..259fe5895032 100644
> --- a/drivers/tty/serial/bcm63xx_uart.c
> +++ b/drivers/tty/serial/bcm63xx_uart.c
> @@ -309,8 +309,8 @@ static void bcm_uart_do_tx(struct uart_port *port)
>  
>  	val = bcm_uart_readl(port, UART_MCTL_REG);
>  	val = (val & UART_MCTL_TXFIFOFILL_MASK) >> UART_MCTL_TXFIFOFILL_SHIFT;
> -
> -	pending = uart_port_tx_limited(port, ch, port->fifosize - val,
> +	pending = uart_port_tx_limited_flags(port, ch, UART_TX_NOSTOP,
> +		port->fifosize - val,
>  		true,
>  		bcm_uart_writel(port, ch, UART_FIFO_REG),
>  		({}));
> @@ -321,6 +321,9 @@ static void bcm_uart_do_tx(struct uart_port *port)
>  	val = bcm_uart_readl(port, UART_IR_REG);
>  	val &= ~UART_TX_INT_MASK;
>  	bcm_uart_writel(port, val, UART_IR_REG);
> +
> +	if (uart_tx_stopped(port))
> +		bcm_uart_stop_tx(port);
>  }
>  
>  /*
> -- 
> 2.34.1
> 
> 

Hi,

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