[PATCH V3] tty: serial: fsl_lpuart: count tty buffer overruns

From: Sherry Sun
Date: Tue Jan 11 2022 - 03:52:48 EST


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

Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx>
---
changes in V3

1. Remove the initialization for copied as it is not necessary.
---
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..7d90c5a530ee 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;

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