Re: [Intel-wired-lan] [PATCH v2 iwl-net] ice: fix destination CGU for dual complex E825

[Simon Horman <horms@kernel.org>]

On Mon, Sep 29, 2025 at 05:29:05PM +0200, Grzegorz Nitka wrote:
> On dual complex E825, only complex 0 has functional CGU (Clock
> Generation Unit), powering all the PHYs.
> SBQ (Side Band Queue) destination device 'cgu' in current implementation
> points to CGU on current complex and, in order to access primary CGU
> from the secondary complex, the driver should use 'cgu_peer' as
> a destination device in read/write CGU registers operations.
> 
> Define new 'cgu_peer' (15) as RDA (Remote Device Access) client over
> SB-IOSF interface and use it as device target when accessing CGU from
> secondary complex.
> 
> This problem has been identified when working on recovery clock
> enablement [1]. In existing implementation for E825 devices, only PF0,
> which is clock owner, is involved in CGU configuration, thus the
> problem was not exposed to the user.
> 
> [1] https://patchwork.ozlabs.org/project/intel-wired-lan/patch/20250905150947.871566-1-grzegorz.nitka@intel.com/
> 
> Fixes: e2193f9f9ec9 ("ice: enable timesync operation on 2xNAC E825 devices")
> Signed-off-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
> Reviewed-by: Arkadiusz Kubalewski <Arkadiusz.kubalewski@intel.com>
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
> ---
> v1->v2:
> - rebased
> - fixed code style coomments (skipped redundant 'else', improved
>   'Return'
>   description in function doc-string)

Reviewed-by: Simon Horman <horms@kernel.org>