Commit b5a3d086 authored Sep 06, 2022 by Marc Kleine-Budde

can: bittiming: can_sjw_check(): check that SJW is not longer than either Phase Buffer Segment

According to "The Configuration of the CAN Bit Timing" [1] the SJW
"may not be longer than either Phase Buffer Segment".

Check SJW against length of both Phase buffers. In case the SJW is
greater, report an error via netlink to user space and bail out.

[1] http://web.archive.org/http://www.oertel-halle.de/files/cia99paper.pdf

Link: https://lore.kernel.org/all/20230202110854.2318594-14-mkl@pengutronix.de


Suggested-by: Vincent Mailhol <vincent.mailhol@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

parent 0c017f09

drivers/net/can/dev/bittiming.c

+14 −0

Original line number	Diff line number	Diff line
		@@ -24,6 +24,20 @@ int can_sjw_check(const struct net_device dev, const struct can_bittiming bt,
		return -EINVAL;
		}

		if (bt->sjw > bt->phase_seg1) {
		NL_SET_ERR_MSG_FMT(extack,
		"sjw: %u greater than phase-seg1: %u",
		bt->sjw, bt->phase_seg1);
		return -EINVAL;
		}

		if (bt->sjw > bt->phase_seg2) {
		NL_SET_ERR_MSG_FMT(extack,
		"sjw: %u greater than phase-seg2: %u",
		bt->sjw, bt->phase_seg2);
		return -EINVAL;
		}

		return 0;
		}