From ee443c8d3e7cf6edbc20c6a2322df31001ff84c7 Mon Sep 17 00:00:00 2001
From: Nico Huber <nico.h@gmx.de>
Date: Mon, 1 Aug 2022 20:23:13 +0200
Subject: drivers/i2c/dw_i2c: Re-add check for empty i2c transfer list

The check was recently removed to allow callers to pass `count == 0`.
Dereferencing the `msg` array is invalid in that case, though. Linux,
where we borrowed the i2c interface from, also treats this with -EINVAL.

Change-Id: I1eec02dd3a3fcf2d477a62cc65292fca40e469d3
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66341
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: Tim Crawford <tcrawford@system76.com>
---
 src/drivers/i2c/designware/dw_i2c.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/drivers/i2c/designware/dw_i2c.c b/src/drivers/i2c/designware/dw_i2c.c
index fdedf63b56..ecd9e88698 100644
--- a/src/drivers/i2c/designware/dw_i2c.c
+++ b/src/drivers/i2c/designware/dw_i2c.c
@@ -467,7 +467,7 @@ static enum cb_err dw_i2c_transfer(unsigned int bus, const struct i2c_msg *msg,
 	size_t start;
 	uint16_t addr;
 
-	if (!msg)
+	if (count == 0 || !msg)
 		return -1;
 
 	/* Break up the transfers at the differing slave address boundary. */
-- 
cgit v1.2.3