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2023-02-07can: j1939: do not wait 250 ms if the same addr was already claimedDevid Antonio Filoni
The ISO 11783-5 standard, in "4.5.2 - Address claim requirements", states: d) No CF shall begin, or resume, transmission on the network until 250 ms after it has successfully claimed an address except when responding to a request for address-claimed. But "Figure 6" and "Figure 7" in "4.5.4.2 - Address-claim prioritization" show that the CF begins the transmission after 250 ms from the first AC (address-claimed) message even if it sends another AC message during that time window to resolve the address contention with another CF. As stated in "4.4.2.3 - Address-claimed message": In order to successfully claim an address, the CF sending an address claimed message shall not receive a contending claim from another CF for at least 250 ms. As stated in "4.4.3.2 - NAME management (NM) message": 1) A commanding CF can d) request that a CF with a specified NAME transmit the address- claimed message with its current NAME. 2) A target CF shall d) send an address-claimed message in response to a request for a matching NAME Taking the above arguments into account, the 250 ms wait is requested only during network initialization. Do not restart the timer on AC message if both the NAME and the address match and so if the address has already been claimed (timer has expired) or the AC message has been sent to resolve the contention with another CF (timer is still running). Signed-off-by: Devid Antonio Filoni <devid.filoni@egluetechnologies.com> Acked-by: Oleksij Rempel <o.rempel@pengutronix.de> Link: https://lore.kernel.org/all/20221125170418.34575-1-devid.filoni@egluetechnologies.com Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2019-09-04can: add support of SAE J1939 protocolThe j1939 authors
SAE J1939 is the vehicle bus recommended practice used for communication and diagnostics among vehicle components. Originating in the car and heavy-duty truck industry in the United States, it is now widely used in other parts of the world. J1939, ISO 11783 and NMEA 2000 all share the same high level protocol. SAE J1939 can be considered the replacement for the older SAE J1708 and SAE J1587 specifications. Acked-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Bastian Stender <bst@pengutronix.de> Signed-off-by: Elenita Hinds <ecathinds@gmail.com> Signed-off-by: kbuild test robot <lkp@intel.com> Signed-off-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be> Signed-off-by: Maxime Jayat <maxime.jayat@mobile-devices.fr> Signed-off-by: Robin van der Gracht <robin@protonic.nl> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>