Messages in this thread | | | From | "Volodymyr Mytnyk [C]" <> | Subject | Re: [PATCH net-next v3] net: marvell: prestera: add firmware v4.0 support | Date | Fri, 22 Oct 2021 22:27:01 +0000 |
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> On Wed, Oct 20, 2021 at 12:32:28PM +0300, Volodymyr Mytnyk wrote: > > From: Volodymyr Mytnyk <vmytnyk@marvell.com> > > > > Add firmware (FW) version 4.0 support for Marvell Prestera > > driver. > > > > Major changes have been made to new v4.0 FW ABI to add support > > of new features, introduce the stability of the FW ABI and ensure > > better forward compatibility for the future driver vesrions. > > > > Current v4.0 FW feature set support does not expect any changes > > to ABI, as it was defined and tested through long period of time. > > The ABI may be extended in case of new features, but it will not > > break the backward compatibility. > > > > ABI major changes done in v4.0: > > - L1 ABI, where MAC and PHY API configuration are split. > > - ACL has been split to low-level TCAM and Counters ABI > > to provide more HW ACL capabilities for future driver > > versions. > > > > To support backward support, the addition compatibility layer is > > required in the driver which will have two different codebase under > > "if FW-VER elif FW-VER else" conditions that will be removed > > in the future anyway, So, the idea was to break backward support > > and focus on more stable FW instead of supporting old version > > with very minimal and limited set of features/capabilities. > > > +/* TODO: add another parameters here: modes, etc... */ > > +struct prestera_port_phy_config { > > + bool admin; > > + u32 mode; > > + u8 mdix; > > +}; > > > @@ -242,10 +246,44 @@ union prestera_msg_port_param { > > u8 duplex; > > u8 fec; > > u8 fc; > > - struct prestera_msg_port_mdix_param mdix; > > - struct prestera_msg_port_autoneg_param autoneg; > > + > > + union { > > + struct { > > + /* TODO: merge it with "mode" */ > > > + struct { > > + /* TODO: merge it with "mode" */ > > + u8 admin:1; > > + u8 adv_enable; > > + u64 modes; > > + /* TODO: merge it with modes */ > > + u32 mode; > > + u8 mdix; > > + } phy; > > You claim this is stable, yet there are four TODOs. Please could you > convince us you can actually do these TODO without breaking the > ABI. Can you add more members to the end of these structures, and the > firmware/driver can know they are there? Since these are often unions, > you might not be able to tell from the length of the message > exchanged.
Those TODOs are not valid anymore, will just remove the comments. No merge is needed :) Adding new members to the end will be fine for the firmware & driver.
> > As Jakub pointed out, your structures have horrible alignment. Have > you run this on both 32 and 64 bit systems? It would be good to add > > BUILD_BUG_ON(sizeof(*foo) != 42) > > for all the structures that get passed to/from the firmware. > > Andrew
Most of the testing is done on 64 bit system. On 32 should be fine also, as the structure is packed & aligned. Anyway, I think to add build checking is good idea to make sure the size is fine on both systems. Thanks.
Volodymyr
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