tty: serial: fsl_lpuart: adjust buffer length to the intended size
[ Upstream commit f73fd750552524b06b5d77ebfdd106ccc8fcac61 ]
Based on the fls function definition provided below, we should not
subtract 1 to obtain the correct buffer length:
fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
Fixes: 5887ad43ee02 ("tty: serial: fsl_lpuart: Use cyclic DMA for Rx")
Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Link: https://lore.kernel.org/r/20230410195555.1003900-1-shenwei.wang@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 20dd476..e7ab8ec 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -998,7 +998,7 @@ static inline int lpuart_start_rx_dma(struct lpuart_port *sport)
* 10ms at any baud rate.
*/
sport->rx_dma_rng_buf_len = (DMA_RX_TIMEOUT * baud / bits / 1000) * 2;
- sport->rx_dma_rng_buf_len = (1 << (fls(sport->rx_dma_rng_buf_len) - 1));
+ sport->rx_dma_rng_buf_len = (1 << fls(sport->rx_dma_rng_buf_len));
if (sport->rx_dma_rng_buf_len < 16)
sport->rx_dma_rng_buf_len = 16;