From 52bb1cb7118564166b04d52387bd8403632f5190 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Date: Thu, 19 May 2022 11:18:06 +0300
Subject: [PATCH] serial: st-asc: Sanitize CSIZE and correct PARENB for CS7
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Git-commit: 52bb1cb7118564166b04d52387bd8403632f5190
Patch-mainline: v5.19-rc1
References: git-fixes

Only CS7 and CS8 seem supported but CSIZE is not sanitized from CS5 or
CS6 to CS8. In addition, ASC_CTL_MODE_7BIT_PAR suggests that CS7 has
to have parity, thus add PARENB.

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: c4b058560762 (serial:st-asc: Add ST ASC driver.)
Cc: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220519081808.3776-8-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/tty/serial/st-asc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c
index d7fd692286cf..1b0da603ab54 100644
--- a/drivers/tty/serial/st-asc.c
+++ b/drivers/tty/serial/st-asc.c
@@ -535,10 +535,14 @@ static void asc_set_termios(struct uart_port *port, struct ktermios *termios,
 	/* set character length */
 	if ((cflag & CSIZE) == CS7) {
 		ctrl_val |= ASC_CTL_MODE_7BIT_PAR;
+		cflag |= PARENB;
 	} else {
 		ctrl_val |= (cflag & PARENB) ?  ASC_CTL_MODE_8BIT_PAR :
 						ASC_CTL_MODE_8BIT;
+		cflag &= ~CSIZE;
+		cflag |= CS8;
 	}
+	termios->c_cflag = cflag;
 
 	/* set stop bit */
 	ctrl_val |= (cflag & CSTOPB) ? ASC_CTL_STOP_2BIT : ASC_CTL_STOP_1BIT;
-- 
2.35.3