From: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> [ Upstream commit 1deeda8d2877c18bc2b9eeee10dd6d2628852848 ] Add CSIZE sanitization for unsupported CSIZE configurations. In addition, if parity is asked for but CSx was unsupported, the sensible result is CS8+parity which requires setting USART_CR1_M0 like with 9 bits. Incorrect CSIZE results in miscalculation of the frame bits in tty_get_char_size() or in its predecessor where the roughly the same code is directly within uart_update_timeout(). Fixes: c8a9d043947b (serial: stm32: fix word length configuration) Cc: Erwan Le Ray <erwan.leray@xxxxxx> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220519081808.3776-9-ilpo.jarvinen@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/tty/serial/stm32-usart.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 9570002d07e7..9bc970be59ba 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -1037,13 +1037,22 @@ static void stm32_usart_set_termios(struct uart_port *port, * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00 * M0 and M1 already cleared by cr1 initialization. */ - if (bits == 9) + if (bits == 9) { cr1 |= USART_CR1_M0; - else if ((bits == 7) && cfg->has_7bits_data) + } else if ((bits == 7) && cfg->has_7bits_data) { cr1 |= USART_CR1_M1; - else if (bits != 8) + } else if (bits != 8) { dev_dbg(port->dev, "Unsupported data bits config: %u bits\n" , bits); + cflag &= ~CSIZE; + cflag |= CS8; + termios->c_cflag = cflag; + bits = 8; + if (cflag & PARENB) { + bits++; + cr1 |= USART_CR1_M0; + } + } if (ofs->rtor != UNDEF_REG && (stm32_port->rx_ch || (stm32_port->fifoen && -- 2.35.1
