[PATCH 5.4 080/107] can: j1939: add rxtimer for multipacket broadcast session

Greg Kroah-Hartman
2020-08-24T09:36:53Z

From: Zhang Changzhong <zhangchangzhong@huawei.com>

[ Upstream commit 0ae18a82686f9b9965a8ce0dd81371871b306ffe ]

According to SAE J1939/21 (Chapter 5.12.3 and APPENDIX C), for transmit side
the required time interval between packets of a multipacket broadcast message
is 50 to 200 ms, the responder shall use a timeout of 250ms (provides margin
allowing for the maximumm spacing of 200ms). For receive side a timeout will
occur when a time of greater than 750 ms elapsed between two message packets
when more packets were expected.

So this patch fix and add rxtimer for multipacket broadcast session.

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Link: https://lore.kernel.org/r/1596599425-5534-5-git-send-email-zhangchangzhong@huawei.com
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/can/j1939/transport.c | 28 ++++++++++++++++++++--------
1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index e3167619b196f..dbd215cbc53d8 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c
@@ -723,10 +723,12 @@ static int j1939_session_tx_rts(struct j1939_session *session)
return ret;

session->last_txcmd = dat[0];
- if (dat[0] == J1939_TP_CMD_BAM)
+ if (dat[0] == J1939_TP_CMD_BAM) {
j1939_tp_schedule_txtimer(session, 50);
-
- j1939_tp_set_rxtimeout(session, 1250);
+ j1939_tp_set_rxtimeout(session, 250);
+ } else {
+ j1939_tp_set_rxtimeout(session, 1250);
+ }

netdev_dbg(session->priv->ndev, "%s: 0x%p\n", __func__, session);

@@ -1687,11 +1689,15 @@ static void j1939_xtp_rx_rts(struct j1939_priv *priv, struct sk_buff *skb,
}
session->last_cmd = cmd;

- j1939_tp_set_rxtimeout(session, 1250);
-
- if (cmd != J1939_TP_CMD_BAM && !session->transmission) {
- j1939_session_txtimer_cancel(session);
- j1939_tp_schedule_txtimer(session, 0);
+ if (cmd == J1939_TP_CMD_BAM) {
+ if (!session->transmission)
+ j1939_tp_set_rxtimeout(session, 750);
+ } else {
+ if (!session->transmission) {
+ j1939_session_txtimer_cancel(session);
+ j1939_tp_schedule_txtimer(session, 0);
+ }
+ j1939_tp_set_rxtimeout(session, 1250);
}

j1939_session_put(session);
@@ -1742,6 +1748,7 @@ static void j1939_xtp_rx_dat_one(struct j1939_session *session,
int offset;
int nbytes;
bool final = false;
+ bool remain = false;
bool do_cts_eoma = false;
int packet;

@@ -1804,6 +1811,8 @@ static void j1939_xtp_rx_dat_one(struct j1939_session *session,
j1939_cb_is_broadcast(&session->skcb)) {
if (session->pkt.rx >= session->pkt.total)
final = true;
+ else
+ remain = true;
} else {
/* never final, an EOMA must follow */
if (session->pkt.rx >= session->pkt.last)
@@ -1813,6 +1822,9 @@ static void j1939_xtp_rx_dat_one(struct j1939_session *session,
if (final) {
j1939_session_timers_cancel(session);
j1939_session_completed(session);
+ } else if (remain) {
+ if (!session->transmission)
+ j1939_tp_set_rxtimeout(session, 750);
} else if (do_cts_eoma) {
j1939_tp_set_rxtimeout(session, 1250);
if (!session->transmission)
--
2.25.1