With commit 132f2d45fb23 ("can: c_can: add support to 64 message objects") the number of message objects used for reception / transmission depends on FIFO size. The ethtools API support allows you to retrieve this info. Driver info has been added too. Link: https://lore.kernel.org/r/20210514165549.14365-2-dariobin@libero.it Signed-off-by: Dario Binacchi <dariobin@libero.it> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>