[PATCH V2] tty: serial: fsl_lpuart: count tty buffer overruns

[PATCH V2] tty: serial: fsl_lpuart: count tty buffer overruns

[Sherry Sun]

Added support for counting the tty buffer overruns in fsl_lpuart driver
like other uart drivers.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>

---
changes in V2
1. Change the copied type to int to avoid implicit conversion, as the
tty_insert_flip_string return type is int.
---
 drivers/tty/serial/fsl_lpuart.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index ce3e26144689..82a1a2817750 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -931,7 +931,8 @@ static void lpuart_rxint(struct lpuart_port *sport)
 			sport->port.sysrq = 0;
 		}
 
-		tty_insert_flip_char(port, rx, flg);
+		if (tty_insert_flip_char(port, rx, flg) == 0)
+			sport->port.icount.buf_overrun++;
 	}
 
 out:
@@ -1024,7 +1025,8 @@ static void lpuart32_rxint(struct lpuart_port *sport)
 				flg = TTY_OVERRUN;
 		}
 
-		tty_insert_flip_char(port, rx, flg);
+		if (tty_insert_flip_char(port, rx, flg) == 0)
+			sport->port.icount.buf_overrun++;
 	}
 
 out:
@@ -1116,7 +1118,7 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
 	struct dma_chan *chan = sport->dma_rx_chan;
 	struct circ_buf *ring = &sport->rx_ring;
 	unsigned long flags;
-	int count = 0;
+	int count = 0, copied = 0;
 
 	if (lpuart_is_32(sport)) {
 		unsigned long sr = lpuart32_read(&sport->port, UARTSTAT);
@@ -1218,20 +1220,24 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
 	if (ring->head < ring->tail) {
 		count = sport->rx_sgl.length - ring->tail;
 
-		tty_insert_flip_string(port, ring->buf + ring->tail, count);
+		copied = tty_insert_flip_string(port, ring->buf + ring->tail, count);
+		if (copied != count)
+			sport->port.icount.buf_overrun++;
 		ring->tail = 0;
-		sport->port.icount.rx += count;
+		sport->port.icount.rx += copied;
 	}
 
 	/* Finally we read data from tail to head */
 	if (ring->tail < ring->head) {
 		count = ring->head - ring->tail;
-		tty_insert_flip_string(port, ring->buf + ring->tail, count);
+		copied = tty_insert_flip_string(port, ring->buf + ring->tail, count);
+		if (copied != count)
+			sport->port.icount.buf_overrun++;
 		/* Wrap ring->head if needed */
 		if (ring->head >= sport->rx_sgl.length)
 			ring->head = 0;
 		ring->tail = ring->head;
-		sport->port.icount.rx += count;
+		sport->port.icount.rx += copied;
 	}
 
 exit:
-- 
2.17.1

Re: [PATCH V2] tty: serial: fsl_lpuart: count tty buffer overruns

[Jiri Slaby]

On 11. 01. 22, 9:22, Sherry Sun wrote:
> Added support for counting the tty buffer overruns in fsl_lpuart driver
> like other uart drivers.
> 
> Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
> 
> ---
> changes in V2
> 1. Change the copied type to int to avoid implicit conversion, as the
> tty_insert_flip_string return type is int.
> ---
>   drivers/tty/serial/fsl_lpuart.c | 20 +++++++++++++-------
>   1 file changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
> index ce3e26144689..82a1a2817750 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
...
> @@ -1116,7 +1118,7 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
>   	struct dma_chan *chan = sport->dma_rx_chan;
>   	struct circ_buf *ring = &sport->rx_ring;
>   	unsigned long flags;
> -	int count = 0;
> +	int count = 0, copied = 0;

Why is it necessary to initialize copied?

Actually neither count needs to be initialized AFAICT. Care to fix that 
too (in a separate patch).

thanks,
-- 
js
suse labs

RE: [PATCH V2] tty: serial: fsl_lpuart: count tty buffer overruns

[Sherry Sun]

Hi Jiri,

> > Added support for counting the tty buffer overruns in fsl_lpuart
> > driver like other uart drivers.
> >
> > Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
> >
> > ---
> > changes in V2
> > 1. Change the copied type to int to avoid implicit conversion, as the
> > tty_insert_flip_string return type is int.
> > ---
> >   drivers/tty/serial/fsl_lpuart.c | 20 +++++++++++++-------
> >   1 file changed, 13 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/tty/serial/fsl_lpuart.c
> > b/drivers/tty/serial/fsl_lpuart.c index ce3e26144689..82a1a2817750
> > 100644
> > --- a/drivers/tty/serial/fsl_lpuart.c
> > +++ b/drivers/tty/serial/fsl_lpuart.c
> ...
> > @@ -1116,7 +1118,7 @@ static void lpuart_copy_rx_to_tty(struct
> lpuart_port *sport)
> >   	struct dma_chan *chan = sport->dma_rx_chan;
> >   	struct circ_buf *ring = &sport->rx_ring;
> >   	unsigned long flags;
> > -	int count = 0;
> > +	int count = 0, copied = 0;
> 
> Why is it necessary to initialize copied?
> 
> Actually neither count needs to be initialized AFAICT. Care to fix that too (in a
> separate patch).
> 
You are right, actually here the initialization for copied is not necessary. I will remove it in V3.
For the initialization for count, I can send another patch to remove it.

Best regards
Sherry