Re: [PATCH v2] IGC: Remove I225_I_PHY_ID checking

[Kevin Traynor <ktraynor@redhat.com>]

On 12/10/2022 08:45, Mah, Yock Gen wrote:
> 
> 
> -----Original Message-----
> From: Kevin Traynor <ktraynor@redhat.com>
> Sent: Tuesday, 11 October, 2022 7:05 PM
> To: IOTG DPDK Ref App <iotg.dpdk.ref.app@intel.com>; Zhang, Qi Z <qi.z.zhang@intel.com>
> Cc: dev@dpdk.org
> Subject: Re: [PATCH v2] IGC: Remove I225_I_PHY_ID checking
> 
> On 31/08/2022 23:51, iotg.dpdk.ref.app@intel.com wrote:
>> From: NSWE SWS DPDK Dev <iotg.dpdk.ref.app@intel.com>
>>
>> i225 devices have only one PHY vendor. There is unnecessary to check
>> _I_PHY_ID during the link establishment and auto-negotiation process,
>> the checking also caused devices like i225-IT failed. This patch is to
>> remove the mentioned unnecessary checking.
>>
>> Cc: stable@dpdk.org
>> Signed-off-by: NSWE SWS DPDK Dev <iotg.dpdk.ref.app@intel.com>
>> ---
>>    drivers/net/igc/base/igc_i225.c | 15 ++-------------
>>    drivers/net/igc/base/igc_phy.c  |  6 ++----
>>    2 files changed, 4 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/net/igc/base/igc_i225.c
>> b/drivers/net/igc/base/igc_i225.c index 5f3d535490..af26602afb 100644
>> --- a/drivers/net/igc/base/igc_i225.c
>> +++ b/drivers/net/igc/base/igc_i225.c
>> @@ -173,19 +173,8 @@ static s32 igc_init_phy_params_i225(struct igc_hw *hw)
>>    	phy->ops.write_reg = igc_write_phy_reg_gpy;
>>    
>>    	ret_val = igc_get_phy_id(hw);
>> -	/* Verify phy id and set remaining function pointers */
>> -	switch (phy->id) {
>> -	case I225_I_PHY_ID:
>> -	case I226_LM_PHY_ID:
>> -		phy->type		= igc_phy_i225;
>> -		phy->ops.set_d0_lplu_state = igc_set_d0_lplu_state_i225;
>> -		phy->ops.set_d3_lplu_state = igc_set_d3_lplu_state_i225;
> 
>> - The commit log says it is removing a check on the ID, but it does not say why these function pointers are being removed.
> 
>> - Why are they removed, were they not needed?
> 
> 
> i225 devices have only one PHY vendor. There is no point checking _I_PHY_ID during the link establishment and auto-negotiation process.
> 

Right, that's clear about the vendor ID check. But it's not clear to me 
why the the resulting code like this:

phy->type = igc_phy_i225;

  and not like this:

phy->type = igc_phy_i225;
phy->ops.set_d0_lplu_state = igc_set_d0_lplu_state_i225;
phy->ops.set_d3_lplu_state = igc_set_d3_lplu_state_i225;

So it is using dummy null functions instead:
https://git.dpdk.org/dpdk/tree/drivers/net/igc/base/igc_phy.c#n61

Do the device registers not need to be set anymore?

>> -		/* TODO - complete with GPY PHY information */
>> -		break;
>> -	default:
>> -		ret_val = -IGC_ERR_PHY;
>> -		goto out;
>> -	}
>> +        phy->type = igc_phy_i225;
>> +
>>    
>>    out:
>>    	return ret_val;
>> diff --git a/drivers/net/igc/base/igc_phy.c
>> b/drivers/net/igc/base/igc_phy.c index 43bbe69bca..2906bae21a 100644
>> --- a/drivers/net/igc/base/igc_phy.c
>> +++ b/drivers/net/igc/base/igc_phy.c
>> @@ -1474,8 +1474,7 @@ s32 igc_phy_setup_autoneg(struct igc_hw *hw)
>>    			return ret_val;
>>    	}
>>    
>> -	if ((phy->autoneg_mask & ADVERTISE_2500_FULL) &&
>> -	    hw->phy.id == I225_I_PHY_ID) {
>> +	if (phy->autoneg_mask & ADVERTISE_2500_FULL) {
>>    	/* Read the MULTI GBT AN Control Register - reg 7.32 */
>>    		ret_val = phy->ops.read_reg(hw, (STANDARD_AN_REG_MASK <<
>>    					    MMD_DEVADDR_SHIFT) |
>> @@ -1615,8 +1614,7 @@ s32 igc_phy_setup_autoneg(struct igc_hw *hw)
>>    		ret_val = phy->ops.write_reg(hw, PHY_1000T_CTRL,
>>    					     mii_1000t_ctrl_reg);
>>    
>> -	if ((phy->autoneg_mask & ADVERTISE_2500_FULL) &&
>> -	    hw->phy.id == I225_I_PHY_ID)
>> +	if (phy->autoneg_mask & ADVERTISE_2500_FULL)
>>    		ret_val = phy->ops.write_reg(hw,
>>    					     (STANDARD_AN_REG_MASK <<
>>    					     MMD_DEVADDR_SHIFT) |
>