On 25.10.2021 14:27:06, Andrew Lunn wrote: > I would not consider it as two different modes, but as N modes. That > way, we are prepared for CAN-3.0 which might need other ring > parameters. ACK - there's CAN-XL, but I haven't seen any HW, yet. Let's follow the zero one infinity rule :) > The netlink API is extensible, unlike the IOCTL interface. I would add > an additional optional attribute, ETHTOOL_A_RINGS_MODE, with values like: > > ETHTOOL_A_RINGS_MODE_DEFAULT > ETHTOOL_A_RINGS_MODE_CAN_2 > ETHTOOL_A_RINGS_MODE_CAN_FD > > The IOCTL would always be for mode _DEFAULT, and it would get/set the > current used setting. If the optionally attribute is missing, then the > calling into the driver would also use _DEFAULT. However, if it is > present, the driver can store away the ring parameters for a > particular mode, and maybe actually put them into use if the mode is > currently active. > > You cannot change > > struct ethtool_ringparam { > __u32 cmd; > __u32 rx_max_pending; > __u32 rx_mini_max_pending; > __u32 rx_jumbo_max_pending; > __u32 tx_max_pending; > __u32 rx_pending; > __u32 rx_mini_pending; > __u32 rx_jumbo_pending; > __u32 tx_pending; > }; > > Since that is ABI. ACK > But you can add an > > struct ethtool_kringparam { > __u32 cmd; > __u32 mode; > __u32 rx_max_pending; > __u32 rx_mini_max_pending; > __u32 rx_jumbo_max_pending; > __u32 tx_max_pending; > __u32 rx_pending; > __u32 rx_mini_pending; > __u32 rx_jumbo_pending; > __u32 tx_pending; > }; > > and use this structure between the ethtool core and the drivers. This > has already been done at least once to allow extending the > API. Semantic patches are good for making the needed changes to all > the drivers. What about the proposed "two new parameters ringparam_ext and extack for .get_ringparam and .set_ringparam to extend more ring params through netlink." by Hao Chen/Guangbin Huang in: https://lore.kernel.org/all/20211014113943.16231-5-huangguangbin2@xxxxxxxxxx/ I personally like the conversion of the in in-kernel API to struct ethtool_kringparam better than adding ringparam_ext. Thanks for you input, regards, Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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