From: Vladimir Oltean <email@example.com> To: Russell King - ARM Linux admin <firstname.lastname@example.org> Cc: Andrew Lunn <email@example.com>, Florian Fainelli <firstname.lastname@example.org>, Heiner Kallweit <email@example.com>, "David S. Miller" <firstname.lastname@example.org>, netdev <email@example.com> Subject: Re: [PATCH net-next 0/5] add phylink support for PCS Date: Wed, 11 Mar 2020 15:57:18 +0200 [thread overview] Message-ID: <CA+h21hpk+TMofHFjg_Z-UZOPp+7zn29ZNLFP+JKreJtbZouiZQ@mail.gmail.com> (raw) In-Reply-To: <20200311125445.GO25745@shell.armlinux.org.uk> On Wed, 11 Mar 2020 at 14:54, Russell King - ARM Linux admin <firstname.lastname@example.org> wrote: > > On Wed, Mar 11, 2020 at 02:46:33PM +0200, Vladimir Oltean wrote: > > Hi Russell, > > > > On Wed, 11 Mar 2020 at 14:09, Russell King - ARM Linux admin > > <email@example.com> wrote: > > > > > > Hi, > > > > > > This series adds support for IEEE 802.3 register set compliant PCS > > > for phylink. In order to do this, we: > > > > > > 1. convert the existing (unused) mii_lpa_to_ethtool_lpa_x() function > > > to a linkmode variant. > > > 2. add a helper for clause 37 advertisements, supporting both the > > > 1000baseX and defacto 2500baseX variants. Note that ethtool does > > > not support half duplex for either of these, and we make no effort > > > to do so. > > > 3. add accessors for modifying a MDIO device register, and use them in > > > phylib, rather than duplicating the code from phylib. > > > > Have you considered accessing the PCS as a phy_device structure, a la > > drivers/net/dsa/ocelot/felix_vsc9959.c? > > I don't want to tie this into phylib, because I don't think phylib > should be dealing with PCS. It brings with it many problems, such as: > Agree that the struct mdio_device -> struct phy_device diff is pretty much useless to a PCS. > 1. how do we know whether the Clause 22 registers are supposed to be > Clause 37 format. Well, they are, aren't they? > 2. how do we program the PCS appropriately for the negotiation results > (which phylib doesn't support). You mean how to read the LPA and logically-AND it with ADV? The PCS doesn't need to be "programmed" according to the resolved link state. Maybe the MAC does. > 3. how do we deal with selecting the appropriate device for the mode > selected (LX2160A has multiple different PCS which depend on the > mode selected.) What I've been doing is to call get_phy_device with an is_c45 argument depending on the PHY interface type. Actually the real problem in your case is that the LX2160A doesn't expose a valid PHY ID in registers 2&3 (unlike other Layerscape PCS implementations), so get_phy_device is likely going to fail unless some sort of PHY ID fixup is not done. > > Note that a phy_device structure embeds a mdio_device structure, and > so these helpers can be used inside phylib if one desires - so this > approach is more flexible than "bolt it into phylib" approach would > be. > It's hard to really say without seeing more than one caller of these new helpers. For example the sja1105 DSA switch has a PCS for SGMII (not supported yet in mainline) that kind-of-emulates a C22 register map, except that it's accessed over SPI, and that the "pcs_get_state" needs to look at some vendor-specific registers too. From that perspective, I was thinking that PHYLINK could be given a phy_device structure with the advertising, supported and lp_advertising linkmode bit fields populated who-knows-how, and PHYLINK just resolves that into its phylink_link_state structure. But then I guess that sort of hardware is not among your target candidates for the generic helpers. Whoever can't expose an MDIO bus or needs to access any vendor-specific register just shouldn't use these functions. And maybe you're right, I don't really know what the balance in practice will be. > > > 4. add support for decoding the advertisement from clause 22 compatible > > > register sets for clause 37 advertisements and SGMII advertisements. > > > 5. add support for clause 45 register sets for 10GBASE-R PCS. > > > > > > These have been tested on the LX2160A Clearfog-CX platform. > > > > > > drivers/net/phy/mdio_bus.c | 55 +++++++++++ > > > drivers/net/phy/phy-core.c | 31 ------ > > > drivers/net/phy/phylink.c | 236 +++++++++++++++++++++++++++++++++++++++++++++ > > > include/linux/mdio.h | 4 + > > > include/linux/mii.h | 57 +++++++---- > > > include/linux/phy.h | 19 ++++ > > > include/linux/phylink.h | 8 ++ > > > include/uapi/linux/mii.h | 5 + > > > 8 files changed, 366 insertions(+), 49 deletions(-) > > > > > > -- > > > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > > > FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up > > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up Regards, -Vladimir
next prev parent reply other threads:[~2020-03-11 13:57 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-11 12:06 Russell King - ARM Linux admin 2020-03-11 12:07 ` [PATCH net-next 1/5] net: mii: convert mii_lpa_to_ethtool_lpa_x() to linkmode variant Russell King 2020-03-11 12:07 ` [PATCH net-next 2/5] net: mii: add linkmode_adv_to_mii_adv_x() Russell King 2020-03-11 12:07 ` [PATCH net-next 3/5] net: mdiobus: add APIs for modifying a MDIO device register Russell King 2020-03-11 12:07 ` [PATCH net-next 4/5] net: phylink: pcs: add 802.3 clause 22 helpers Russell King 2020-03-11 14:06 ` Vladimir Oltean 2020-03-11 17:09 ` Russell King - ARM Linux admin 2020-03-11 18:44 ` Vladimir Oltean 2020-03-11 19:32 ` Russell King - ARM Linux admin 2020-03-11 19:59 ` Vladimir Oltean 2020-03-11 20:32 ` Russell King - ARM Linux admin 2020-03-12 12:54 ` Vladimir Oltean 2020-03-12 13:13 ` Russell King - ARM Linux admin 2020-03-12 13:35 ` Vladimir Oltean 2020-03-11 12:07 ` [PATCH net-next 5/5] net: phylink: pcs: add 802.3 clause 45 helpers Russell King 2020-03-11 12:46 ` [PATCH net-next 0/5] add phylink support for PCS Vladimir Oltean 2020-03-11 12:54 ` Russell King - ARM Linux admin 2020-03-11 13:57 ` Vladimir Oltean [this message] 2020-03-11 17:05 ` Russell King - ARM Linux admin 2020-03-11 18:16 ` Vladimir Oltean
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