On 7/11/19 2:36 PM, Max Staudt wrote: > This is the elmcan driver. It does a surprisingly good job at turning > ELM327 based OBD-II interfaces into cheap CAN interfaces for simple > homebrew projects. > > Please see the included documentation for details and limitations: > Documentation/networking/device_drivers/elmcan.rst > > Thanks to Oliver Neukum for his reviews, wisdom, and encouragement > while writing this. > > CC TTY maintainers for their opinion as this patch adds a new ldisc. Can you convert the driver from a ldisc to a serdev driver? There is also the problem of using netif_rx_ni(skb) to push the frames into networking stack. With this function the CAN frames might not end up in the user space in the correct order. You have to use netif_receive_skb(skb) to avoid this problem. However this is a bit more complicated, as you can only use this function from the NAPI context. You can setup a rx_offload, via can_rx_offload_add_fifo() and then use can_rx_offload_queue_tail() to push the CAN frames to the networking stack. See the flexcan driver as an example. Use this [1] version as a reference how to use can_rx_offload_queue_tail(). It's used here for error frames, but you can use it for normal frames as well. Marc [1] https://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can.git/tree/drivers/net/can/flexcan.c?id=4530ec36bb1e0d24f41c33229694adacda3d5d89#n613 -- Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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