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Date: Mon, 10 Jun 2024 07:16:09 +0200
From: Oleksij Rempel <o.rempel@pengutronix.de>
To: Kory Maincent <kory.maincent@bootlin.com>
Cc: "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Donald Hunter <donald.hunter@gmail.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	Dent Project <dentproject@linuxfoundation.org>,
	kernel@pengutronix.de
Subject: Re: [PATCH net-next v2 2/8] net: ethtool: pse-pd: Expand C33 PSE
 status with class, power and extended state
Message-ID: <ZmaMGWMOvILHy8Iu@pengutronix.de>
References: <20240607-feature_poe_power_cap-v2-0-c03c2deb83ab@bootlin.com>
 <20240607-feature_poe_power_cap-v2-2-c03c2deb83ab@bootlin.com>
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In-Reply-To: <20240607-feature_poe_power_cap-v2-2-c03c2deb83ab@bootlin.com>

Hi Köry,

Thank you for your work.

On Fri, Jun 07, 2024 at 09:30:19AM +0200, Kory Maincent wrote:
> From: "Kory Maincent (Dent Project)" <kory.maincent@bootlin.com>

...

>  /**
> diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
> index 8733a3117902..ef65ad4612d2 100644
> --- a/include/uapi/linux/ethtool.h
> +++ b/include/uapi/linux/ethtool.h
> @@ -752,6 +752,47 @@ enum ethtool_module_power_mode {
>  	ETHTOOL_MODULE_POWER_MODE_HIGH,
>  };
>  
> +/* C33 PSE extended state */
> +enum ethtool_c33_pse_ext_state {
> +	ETHTOOL_C33_PSE_EXT_STATE_UNKNOWN = 1,

I assume, In case the state is unknown, better to set it to 0 and not
report it to the user space in the first place. Do we really need it?

> +	ETHTOOL_C33_PSE_EXT_STATE_DETECTION,
> +	ETHTOOL_C33_PSE_EXT_STATE_CLASSIFICATION_FAILURE,
> +	ETHTOOL_C33_PSE_EXT_STATE_HARDWARE_ISSUE,
> +	ETHTOOL_C33_PSE_EXT_STATE_VOLTAGE_ISSUE,
> +	ETHTOOL_C33_PSE_EXT_STATE_CURRENT_ISSUE,
> +	ETHTOOL_C33_PSE_EXT_STATE_POWER_BUDGET_EXCEEDED,

What is the difference between POWER_BUDGET_EXCEEDED and
STATE_CURRENT_ISSUE->CRT_OVERLOAD? If there is some difference, it
should be commented.

Please provide comments describing how all of this states and substates
should be used.

> +	ETHTOOL_C33_PSE_EXT_STATE_CONFIG,
> +	ETHTOOL_C33_PSE_EXT_STATE_TEMP_ISSUE,
> +};

...

>  /**
>   * enum ethtool_pse_types - Types of PSE controller.
>   * @ETHTOOL_PSE_UNKNOWN: Type of PSE controller is unknown
> diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
> index b49b804b9495..ccbe8294dfd5 100644
> --- a/include/uapi/linux/ethtool_netlink.h
> +++ b/include/uapi/linux/ethtool_netlink.h
> @@ -915,6 +915,10 @@ enum {
>  	ETHTOOL_A_C33_PSE_ADMIN_STATE,		/* u32 */
>  	ETHTOOL_A_C33_PSE_ADMIN_CONTROL,	/* u32 */
>  	ETHTOOL_A_C33_PSE_PW_D_STATUS,		/* u32 */
> +	ETHTOOL_A_C33_PSE_PW_CLASS,		/* u32 */
> +	ETHTOOL_A_C33_PSE_ACTUAL_PW,		/* u32 */
> +	ETHTOOL_A_C33_PSE_EXT_STATE,		/* u8 */
> +	ETHTOOL_A_C33_PSE_EXT_SUBSTATE,		/* u8 */

Please, increase the size to u32 for state and substate.

>  	/* add new constants above here */
>  	__ETHTOOL_A_PSE_CNT,
> diff --git a/net/ethtool/pse-pd.c b/net/ethtool/pse-pd.c
> index 2c981d443f27..3d74cfe7765b 100644
> --- a/net/ethtool/pse-pd.c
> +++ b/net/ethtool/pse-pd.c
> @@ -86,7 +86,14 @@ static int pse_reply_size(const struct ethnl_req_info *req_base,
>  		len += nla_total_size(sizeof(u32)); /* _C33_PSE_ADMIN_STATE */
>  	if (st->c33_pw_status > 0)
>  		len += nla_total_size(sizeof(u32)); /* _C33_PSE_PW_D_STATUS */
> -
> +	if (st->c33_pw_class > 0)
> +		len += nla_total_size(sizeof(u32)); /* _C33_PSE_PW_CLASS */
> +	if (st->c33_actual_pw > 0)
> +		len += nla_total_size(sizeof(u32)); /* _C33_PSE_ACTUAL_PW */
> +	if (st->c33_ext_state_info.c33_pse_ext_state)
> +		len += nla_total_size(sizeof(u8)); /* _C33_PSE_EXT_STATE */
> +	if (st->c33_ext_state_info.__c33_pse_ext_substate)
> +		len += nla_total_size(sizeof(u8)); /* _C33_PSE_EXT_SUBSTATE */

Substate can be properly decoded only if state is not zero.

>  	return len;
>  }
>  
> @@ -117,6 +124,26 @@ static int pse_fill_reply(struct sk_buff *skb,
>  			st->c33_pw_status))
>  		return -EMSGSIZE;
>  
> +	if (st->c33_pw_class > 0 &&
> +	    nla_put_u32(skb, ETHTOOL_A_C33_PSE_PW_CLASS,
> +			st->c33_pw_class))
> +		return -EMSGSIZE;
> +
> +	if (st->c33_actual_pw > 0 &&
> +	    nla_put_u32(skb, ETHTOOL_A_C33_PSE_ACTUAL_PW,
> +			st->c33_actual_pw))
> +		return -EMSGSIZE;
> +
> +	if (st->c33_ext_state_info.c33_pse_ext_state > 0 &&
> +	    nla_put_u8(skb, ETHTOOL_A_C33_PSE_EXT_STATE,
> +		       st->c33_ext_state_info.c33_pse_ext_state))
> +		return -EMSGSIZE;
> +
> +	if (st->c33_ext_state_info.__c33_pse_ext_substate > 0 &&
> +	    nla_put_u8(skb, ETHTOOL_A_C33_PSE_EXT_SUBSTATE,
> +		       st->c33_ext_state_info.__c33_pse_ext_substate))
> +		return -EMSGSIZE;

ditto.

Please update Documentation/networking/ethtool-netlink.rst

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