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Date: Mon, 10 Jun 2024 11:25:59 +0200
From: Kory Maincent <kory.maincent@bootlin.com>
To: Oleksij Rempel <o.rempel@pengutronix.de>
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: <20240610112559.57806b8c@kmaincent-XPS-13-7390>
In-Reply-To: <ZmaMGWMOvILHy8Iu@pengutronix.de>
References: <20240607-feature_poe_power_cap-v2-0-c03c2deb83ab@bootlin.com>
	<20240607-feature_poe_power_cap-v2-2-c03c2deb83ab@bootlin.com>
	<ZmaMGWMOvILHy8Iu@pengutronix.de>
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Hello Oleksij,

On Mon, 10 Jun 2024 07:16:09 +0200
Oleksij Rempel <o.rempel@pengutronix.de> wrote:

> Hi K=C3=B6ry,
>=20
> Thank you for your work.
>=20
> On Fri, Jun 07, 2024 at 09:30:19AM +0200, Kory Maincent wrote:
> > From: "Kory Maincent (Dent Project)" <kory.maincent@bootlin.com> =20
>=20
> ...
>=20
> >  /**
> > 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,
> >  };
> > =20
> > +/* C33 PSE extended state */
> > +enum ethtool_c33_pse_ext_state {
> > +	ETHTOOL_C33_PSE_EXT_STATE_UNKNOWN =3D 1, =20
>=20
> 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?

The pd692x0 report this for the unknown state: "Port is not mapped to physi=
cal
port, port is in unknown state, or PD692x0 fails to communicate with PD69208
device allocated for this port."
Also it has a status for open port (not connected) state.
(ETHTOOL_C33_PSE_EXT_SUBSTATE_V_OPEN)
Do you prefer to use the same error for both state?
=20
> > +	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, =20
>=20
> What is the difference between POWER_BUDGET_EXCEEDED and
> STATE_CURRENT_ISSUE->CRT_OVERLOAD? If there is some difference, it
> should be commented.

Current overload seems to be describing the "Overload current detection ran=
ge
(Icut)" As described in the IEEE standard.
Not sure If budget exceeded should use the same error.

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

The enum errors I wrote is a bit subjective and are taken from the PD692x0
port status list. Go ahead to purpose any change, I have tried to make
categories that make sense but I might have made wrong choice.

> >  /**
> >   * 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 */ =20
>=20
> Please, increase the size to u32 for state and substate.

Ack,

> >  	/* 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 +=3D nla_total_size(sizeof(u32)); /* _C33_PSE_ADMIN_STAT=
E */
> >  	if (st->c33_pw_status > 0)
> >  		len +=3D nla_total_size(sizeof(u32)); /*
> > _C33_PSE_PW_D_STATUS */ -
> > +	if (st->c33_pw_class > 0)
> > +		len +=3D nla_total_size(sizeof(u32)); /* _C33_PSE_PW_CLASS */
> > +	if (st->c33_actual_pw > 0)
> > +		len +=3D nla_total_size(sizeof(u32)); /* _C33_PSE_ACTUAL_PW
> > */
> > +	if (st->c33_ext_state_info.c33_pse_ext_state)
> > +		len +=3D nla_total_size(sizeof(u8)); /* _C33_PSE_EXT_STATE */
> > +	if (st->c33_ext_state_info.__c33_pse_ext_substate)
> > +		len +=3D nla_total_size(sizeof(u8)); /*
> > _C33_PSE_EXT_SUBSTATE */ =20
>=20
> Substate can be properly decoded only if state is not zero.

Indeed, thanks for spotting that mistake.
=20
> Please update Documentation/networking/ethtool-netlink.rst

Oh right, indeed. Forgot to add the netlink docs.=20

Regards,
--=20
K=C3=B6ry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com