On Thu, 14 Jul 2022, Shenwei Wang wrote:
> The LPUART hardware doesn't zero out the parity bit on the received
> characters. This behavior won't impact the use cases of CS8 because
> the parity bit is the 9th bit which is not currently used by software.
> But the parity bit for CS7 must be zeroed out by software in order to
> get the correct raw data.
This problem only occurs with the lpuart32 variant? Or should the other
functions be changed as well?
--
i.
> Signed-off-by: Shenwei Wang <shenwei.wang@xxxxxxx>
> ---
> changes in v2
> - remove the "inline" keyword from the function of lpuart_tty_insert_flip_string;
>
> changes in v1
> - fix the code indent and whitespace issue;
>
> drivers/tty/serial/fsl_lpuart.c | 26 ++++++++++++++++++++++++--
> 1 file changed, 24 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
> index fc7d235a1e270..afa0f941c862f 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -274,6 +274,8 @@ struct lpuart_port {
> int rx_dma_rng_buf_len;
> unsigned int dma_tx_nents;
> wait_queue_head_t dma_wait;
> + bool is_cs7; /* Set to true when character size is 7 */
> + /* and the parity is enabled */
> };
>
> struct lpuart_soc_data {
> @@ -1022,6 +1024,9 @@ static void lpuart32_rxint(struct lpuart_port *sport)
> flg = TTY_OVERRUN;
> }
>
> + if (sport->is_cs7)
> + rx &= 0x7F;
> +
> if (tty_insert_flip_char(port, rx, flg) == 0)
> sport->port.icount.buf_overrun++;
> }
> @@ -1107,6 +1112,17 @@ static void lpuart_handle_sysrq(struct lpuart_port *sport)
> }
> }
>
> +static int lpuart_tty_insert_flip_string(struct tty_port *port,
> + unsigned char *chars, size_t size, bool is_cs7)
> +{
> + int i;
> +
> + if (is_cs7)
> + for (i = 0; i < size; i++)
> + chars[i] &= 0x7F;
> + return tty_insert_flip_string(port, chars, size);
> +}
> +
> static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
> {
> struct tty_port *port = &sport->port.state->port;
> @@ -1217,7 +1233,8 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
> if (ring->head < ring->tail) {
> count = sport->rx_sgl.length - ring->tail;
>
> - copied = tty_insert_flip_string(port, ring->buf + ring->tail, count);
> + copied = lpuart_tty_insert_flip_string(port, ring->buf + ring->tail,
> + count, sport->is_cs7);
> if (copied != count)
> sport->port.icount.buf_overrun++;
> ring->tail = 0;
> @@ -1227,7 +1244,8 @@ static void lpuart_copy_rx_to_tty(struct lpuart_port *sport)
> /* Finally we read data from tail to head */
> if (ring->tail < ring->head) {
> count = ring->head - ring->tail;
> - copied = tty_insert_flip_string(port, ring->buf + ring->tail, count);
> + copied = lpuart_tty_insert_flip_string(port, ring->buf + ring->tail,
> + count, sport->is_cs7);
> if (copied != count)
> sport->port.icount.buf_overrun++;
> /* Wrap ring->head if needed */
> @@ -2066,6 +2084,7 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios,
> ctrl = old_ctrl = lpuart32_read(&sport->port, UARTCTRL);
> bd = lpuart32_read(&sport->port, UARTBAUD);
> modem = lpuart32_read(&sport->port, UARTMODIR);
> + sport->is_cs7 = false;
> /*
> * only support CS8 and CS7, and for CS7 must enable PE.
> * supported mode:
> @@ -2184,6 +2203,9 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios,
> lpuart32_write(&sport->port, ctrl, UARTCTRL);
> /* restore control register */
>
> + if ((ctrl & (UARTCTRL_PE | UARTCTRL_M)) == UARTCTRL_PE)
> + sport->is_cs7 = true;
> +
> if (old && sport->lpuart_dma_rx_use) {
> if (!lpuart_start_rx_dma(sport))
> rx_dma_timer_init(sport);
> --
> 2.25.1
>
