Re: [PATCH net-next v3] net: marvell: prestera: add firmware v4.0 support

Hi Andrew

On Wed, Oct 20, 2021 at 12:32:28PM +0300, Volodymyr Mytnyk wrote:

quoted

From: Volodymyr Mytnyk <redacted>

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.

So if we decide to merge this, we will hold you to this statement. You can never again break the ABI. The driver will always support v4.0 firmware.

Are you really sure you have it correct this time?

    Andrew

So, the v4.0 FW supports stable ABI for the following set of features:

  - L1 port management
  - lag, vlans
  - routing, ecmp
  - tc templates, chains, conntrack, policer
  - bridge port insolation
  - HW counters
  - storm control

Some of those features are not fully supported yet by the driver. So, while we support these in the driver, the ABI is not expected to be changed.
Of course, with new features to come, the FW will be extended, while the backward compatibility will remain stable with the previous FW version. 
Bottom line, for this set of features, the ABI is expected to remain as is.

  Volodymyr