From: Ilpo Järvinen ilpo.jarvinen@linux.intel.com
[ 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@st.com Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Link: https://lore.kernel.org/r/20220519081808.3776-9-ilpo.jarvinen@linux.intel.co... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 6afae051ba8d..8cd9e5b077b6 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -810,13 +810,22 @@ 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)) {