Re: [PATCH net-next v9 02/12] net: phylink: introduce internal phylink PCS handling

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Hi,

On 7/17/26 08:54, Christian Marangi wrote:
> Introduce internal handling of PCS for phylink. This is an alternative
> way to .mac_select_pcs that moves the selection logic of the PCS entirely
> to phylink with the usage of the supported_interface value in the PCS
> struct.
> 
> MAC should now provide a callback to fill the available PCS in
> phylink_config in .fill_available_pcs and fill the .num_possible_pcs with
> the number of elements in the array. MAC should also define a new bitmap,
> pcs_interfaces, in phylink_config to define for what interface mode a
> dedicated PCS is required.
> 
> On phylink_create(), an array of PCS pointer is allocated of size
> .num_possible_pcs from phylink_config and .fill_available_pcs from
> phylink_config is called passing as args the just allocated array and
> the number of possible element in it.
> 
> MAC will fill this passed array with all the available PCS.
> 
> This array is then parsed and a linked list of PCS is created based on
> the allocated PCS array filled by MAC via .fill_available_pcs().
> 
> Every PCS in phylink PCS list gets then linked to the phylink instance
> by setting the phylink value in phylink_pcs struct to the phylink instance.
> Also the supported_interface value in phylink struct is updated with
> the new supported_interface from the provided PCS.
> 
> On phylink_destroy(), every PCS in phylink PCS list is unlinked from the
> phylink instance by setting the phylink value in phylink_pcs struct to NULL
> and removed from the PCS list.
> 
> phylink_validate_mac_and_pcs(), phylink_major_config() and
> phylink_inband_caps() are updated to support this new implementation
> with the PCS list stored in phylink.
> 
> They will make use of phylink_validate_pcs_interface() that will loop
> for every PCS in the phylink PCS available list and find one that supports
> the passed interface.
> 
> phylink_validate_pcs_interface() applies the same logic of .mac_select_pcs
> where if a supported_interface value is not set for the PCS struct, then
> it's assumed every interface is supported.
> 
> A MAC is required to implement either a .mac_select_pcs or make use of
> the PCS list implementation. Implementing both will result in a fail
> on phylink_create().
> 
> A MAC defining .num_possible_pcs in phylink_config MUST also define a
> .fill_available_pcs or phylink_create() will fail with an negative error.
> 
> phylink value in phylink_pcs struct with this implementation is used to
> track from PCS side when it's attached to a phylink instance. PCS driver
> will make use of this information to correctly detach from a phylink
> instance if needed.
> 
> phylink_pcs_change() is also changed to verify that the PCS that triggered
> a link change is the one that is currently used by the phylink instance.
> 
> The .mac_select_pcs implementation is not changed but it's expected that
> every MAC driver migrates to the new implementation to later deprecate
> and remove .mac_select_pcs.
> 
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>

Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Maxime