[PATCH 3/5] serial: fsl_lpuart: Remove custom frame size calculation

From: Ilpo Järvinen
Date: Thu Aug 25 2022 - 04:58:49 EST


The number of bits can be calculated using tty_get_frame_size(), no
need for the driver to do it on its own.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/fsl_lpuart.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index f6c33cd228c8..926460f1dc08 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1284,23 +1284,19 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
struct dma_slave_config dma_rx_sconfig = {};
struct circ_buf *ring = &sport->rx_ring;
int ret, nent;
- int bits, baud;
+ int baud;
struct tty_port *port = &sport->port.state->port;
struct tty_struct *tty = port->tty;
struct ktermios *termios = &tty->termios;
struct dma_chan *chan = sport->dma_rx_chan;

baud = tty_get_baud_rate(tty);
-
- bits = (termios->c_cflag & CSIZE) == CS7 ? 9 : 10;
- if (termios->c_cflag & PARENB)
- bits++;
-
/*
* Calculate length of one DMA buffer size to keep latency below
* 10ms at any baud rate.
*/
- sport->rx_dma_rng_buf_len = (DMA_RX_TIMEOUT * baud / bits / 1000) * 2;
+ sport->rx_dma_rng_buf_len = (DMA_RX_TIMEOUT * baud / tty_get_frame_size(termios->c_cflag) /
+ 1000) * 2;
sport->rx_dma_rng_buf_len = (1 << (fls(sport->rx_dma_rng_buf_len) - 1));
if (sport->rx_dma_rng_buf_len < 16)
sport->rx_dma_rng_buf_len = 16;
--
2.30.2