netdev - Re: [PATCH net-next v2 2/2] amd-xgbe: add support for rx-adaptation

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Date:   Fri, 3 Feb 2023 13:49:01 +0530
From:   Raju Rangoju <Raju.Rangoju@....com>
To:     Simon Horman <simon.horman@...igine.com>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     netdev@...r.kernel.org, davem@...emloft.net, kuba@...nel.org,
        edumazet@...gle.com, Shyam-sundar.S-k@....com
Subject: Re: [PATCH net-next v2 2/2] amd-xgbe: add support for rx-adaptation



On 2/3/2023 1:39 PM, Simon Horman wrote:
> On Thu, Feb 02, 2023 at 03:16:50PM +0100, Paolo Abeni wrote:
>> On Wed, 2023-02-01 at 18:11 +0100, Simon Horman wrote:
>>> On Wed, Feb 01, 2023 at 11:19:32AM +0530, Raju Rangoju wrote:
>>>> The existing implementation for non-Autonegotiation 10G speed modes does
>>>> not enable RX adaptation in the Driver and FW. The RX Equalization
>>>> settings (AFE settings alone) are manually configured and the existing
>>>> link-up sequence in the driver does not perform rx adaptation process as
>>>> mentioned in the Synopsys databook. There's a customer request for 10G
>>>> backplane mode without Auto-negotiation and for the DAC cables of more
>>>> significant length that follow the non-Autonegotiation mode. These modes
>>>> require PHY to perform RX Adaptation.
>>>>
>>>> The proposed logic adds the necessary changes to Yellow Carp devices to
>>>> ensure seamless RX Adaptation for 10G-SFI (LONG DAC) and 10G-KR without
>>>> AN (CL72 not present). The RX adaptation core algorithm is executed by
>>>> firmware, however, to achieve that a new mailbox sub-command is required
>>>> to be sent by the driver.
>>>>
>>>> Co-developed-by: Shyam Sundar S K <Shyam-sundar.S-k@....com>
>>>> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@....com>
>>>> Signed-off-by: Raju Rangoju <Raju.Rangoju@....com>
>>>
>>> ...
>>>
>>>> diff --git a/drivers/net/ethernet/amd/xgbe/xgbe.h b/drivers/net/ethernet/amd/xgbe/xgbe.h
>>>> index 16e73df3e9b9..ad136ed493ed 100644
>>>> --- a/drivers/net/ethernet/amd/xgbe/xgbe.h
>>>> +++ b/drivers/net/ethernet/amd/xgbe/xgbe.h
>>>> @@ -625,6 +625,7 @@ enum xgbe_mb_cmd {
>>>>   
>>>>   enum xgbe_mb_subcmd {
>>>>   	XGBE_MB_SUBCMD_NONE = 0,
>>>> +	XGBE_MB_SUBCMD_RX_ADAP,
>>>>   
>>>>   	/* 10GbE SFP subcommands */
>>>>   	XGBE_MB_SUBCMD_ACTIVE = 0,
>>>> @@ -1316,6 +1317,10 @@ struct xgbe_prv_data {
>>>>   
>>>>   	bool debugfs_an_cdr_workaround;
>>>>   	bool debugfs_an_cdr_track_early;
>>>> +	bool en_rx_adap;
>>>
>>> nit: there is a 1 byte hole here (on x86_64)
>>
>> I think even in the current form is ok. The total size of the struct is
>> not going to change, due to alignment, and the fields will sit in the
>> same cacheline in both cases.
>>
>> I guess the layout could be changed later if needed.
> 
> Ok, I did think it was worth mentioning.
> But I agree that it doesn't need to be changed at this time.

Thanks Simon for taking time to review the patch. I'll try to handle it 
at a later point in time.