| Message ID | 559FF63E.8020209@list.ru |
|---|---|
| State | Needs Review / ACK, archived |
| Headers | show |
| Context | Check | Description |
|---|---|---|
| robh/checkpatch | warning | total: 1 errors, 0 warnings, 0 lines checked |
| robh/patch-applied | success |
On 10/07/15 09:43, Stas Sergeev wrote: > > Currently for fixed-link the MAC driver decides whether to use the > link status auto-negotiation or not. > Unfortunately the auto-negotiation may not work when expected by > the MAC driver. Sebastien Rannou explains: > << Yes, I confirm that my HW does not generate an in-band status. AFAIK, it's > a PHY that aggregates 4xSGMIIs to 1xQSGMII ; the MAC side of the PHY (with > inband status) is connected to the switch through QSGMII, and in this context > we are on the media side of the PHY. >> > https://lkml.org/lkml/2015/7/10/206 > > This patch introduces the new boolean property 'autoneg' that allows > the user to request the auto-negotiation explicitly. The implementation looks better, but the name might still be slightly controversial. I would go with "use-in-band-status" which is more strictly defined than "autoneg" which could mean anything and everything. What do you think? > > Signed-off-by: Stas Sergeev <stsp@users.sourceforge.net> > > CC: Rob Herring <robh+dt@kernel.org> > CC: Pawel Moll <pawel.moll@arm.com> > CC: Mark Rutland <mark.rutland@arm.com> > CC: Ian Campbell <ijc+devicetree@hellion.org.uk> > CC: Kumar Gala <galak@codeaurora.org> > CC: Florian Fainelli <f.fainelli@gmail.com> > CC: Grant Likely <grant.likely@linaro.org> > CC: devicetree@vger.kernel.org > CC: linux-kernel@vger.kernel.org > CC: netdev@vger.kernel.org > --- > .../devicetree/bindings/net/fixed-link.txt | 6 +++++- > drivers/of/of_mdio.c | 23 ++++++++++++++++++++-- > include/linux/of_mdio.h | 5 +++++ > 3 files changed, 31 insertions(+), 3 deletions(-) > > diff --git a/Documentation/devicetree/bindings/net/fixed-link.txt b/Documentation/devicetree/bindings/net/fixed-link.txt > index 82bf7e0..e2959a8 100644 > --- a/Documentation/devicetree/bindings/net/fixed-link.txt > +++ b/Documentation/devicetree/bindings/net/fixed-link.txt > @@ -9,8 +9,12 @@ Such a fixed link situation is described by creating a 'fixed-link' > sub-node of the Ethernet MAC device node, with the following > properties: > > +* 'autoneg' (boolean, optional), to enable the auto-negotiation of link > + state. Auto-negotiation is MII protocol, HW and driver-specific and is > + not supported in many cases, so use it only when you know what you do. > * 'speed' (integer, mandatory), to indicate the link speed. Accepted > - values are 10, 100 and 1000 > + values are 10, 100 and 1000. If the auto-negotiation is enabled, > + 'speed' may not be set. It will then be auto-negotiated, if possible. > * 'full-duplex' (boolean, optional), to indicate that full duplex is > used. When absent, half duplex is assumed. > * 'pause' (boolean, optional), to indicate that pause should be > diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c > index 1bd4305..12b2ede 100644 > --- a/drivers/of/of_mdio.c > +++ b/drivers/of/of_mdio.c > @@ -280,6 +280,22 @@ bool of_phy_is_fixed_link(struct device_node *np) > } > EXPORT_SYMBOL(of_phy_is_fixed_link); > > +bool of_phy_is_autoneg_link(struct device_node *np) > +{ > + struct device_node *dn; > + bool ret; > + > + dn = of_get_child_by_name(np, "fixed-link"); > + if (!dn) > + return false; > + > + ret = of_property_read_bool(dn, "autoneg"); > + > + of_node_put(dn); > + return ret; > +} > +EXPORT_SYMBOL(of_phy_is_autoneg_link); > + > int of_phy_register_fixed_link(struct device_node *np) > { > struct fixed_phy_status status = {}; > @@ -291,10 +307,13 @@ int of_phy_register_fixed_link(struct device_node *np) > /* New binding */ > fixed_link_node = of_get_child_by_name(np, "fixed-link"); > if (fixed_link_node) { > - status.link = 1; > + bool autoneg = of_property_read_bool(fixed_link_node, > + "autoneg"); > + status.link = !autoneg; > status.duplex = of_property_read_bool(fixed_link_node, > "full-duplex"); > - if (of_property_read_u32(fixed_link_node, "speed", &status.speed)) > + if (of_property_read_u32(fixed_link_node, "speed", > + &status.speed) != 0 && !autoneg) > return -EINVAL; > status.pause = of_property_read_bool(fixed_link_node, "pause"); > status.asym_pause = of_property_read_bool(fixed_link_node, > diff --git a/include/linux/of_mdio.h b/include/linux/of_mdio.h > index d449018..647f348 100644 > --- a/include/linux/of_mdio.h > +++ b/include/linux/of_mdio.h > @@ -65,6 +65,7 @@ static inline struct mii_bus *of_mdio_find_bus(struct device_node *mdio_np) > #if defined(CONFIG_OF) && defined(CONFIG_FIXED_PHY) > extern int of_phy_register_fixed_link(struct device_node *np); > extern bool of_phy_is_fixed_link(struct device_node *np); > +extern bool of_phy_is_autoneg_link(struct device_node *np); > #else > static inline int of_phy_register_fixed_link(struct device_node *np) > { > @@ -74,6 +75,10 @@ static inline bool of_phy_is_fixed_link(struct device_node *np) > { > return false; > } > +static inline bool of_phy_is_autoneg_link(struct device_node *np) > +{ > + return false; > +} > #endif > >
10.07.2015 21:37, Florian Fainelli пишет: > On 10/07/15 09:43, Stas Sergeev wrote: >> Currently for fixed-link the MAC driver decides whether to use the >> link status auto-negotiation or not. >> Unfortunately the auto-negotiation may not work when expected by >> the MAC driver. Sebastien Rannou explains: >> << Yes, I confirm that my HW does not generate an in-band status. AFAIK, it's >> a PHY that aggregates 4xSGMIIs to 1xQSGMII ; the MAC side of the PHY (with >> inband status) is connected to the switch through QSGMII, and in this context >> we are on the media side of the PHY. >> >> https://lkml.org/lkml/2015/7/10/206 >> >> This patch introduces the new boolean property 'autoneg' that allows >> the user to request the auto-negotiation explicitly. > The implementation looks better, but the name might still be slightly > controversial. I would go with "use-in-band-status" which is more > strictly defined than "autoneg" which could mean anything and everything. > > What do you think? I actually think autoneg is a bit better. - Autonegotiation is a widely used and known term: https://en.wikipedia.org/wiki/Autonegotiation And who knows what in-band status is? And, more importantly, who knows what is it used for? Who even knows it is used for autonegotiation? - When we set autoneg for fixed-link, we basically just say "no MDIO here, but please do autoneg by any other means, if possible". - in-band status is an implementation delail, and it is specific to a particular protocols. If you request the in-band status for some protocol that doesn't support it, perhaps you should get -EINVAL, because such a config makes no sense. With autonegotiation, the rules are not that strict: it can be "unimplemented", which doesn't necessary mean nonsense in the config. - autonegotiation is a wider term, and may be implemented by some other means than the in-band status (which is probably impossible for a fixed-link though). - In the terms that the driver uses, it is autonegotiation, eg MVNETA_GMAC_AUTONEG_CONFIG. And when you go down the implementation details, you see MVNETA_GMAC_INBAND_AN_ENABLE, which is just one AN bit of many. So I really would prefer to keep things as is. But if you insist, I can rename, but there will still be no -EINVAL checks for obviously wrong configs. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10/07/15 13:08, Stas Sergeev wrote: > 10.07.2015 21:37, Florian Fainelli пишет: >> On 10/07/15 09:43, Stas Sergeev wrote: >>> Currently for fixed-link the MAC driver decides whether to use the >>> link status auto-negotiation or not. >>> Unfortunately the auto-negotiation may not work when expected by >>> the MAC driver. Sebastien Rannou explains: >>> << Yes, I confirm that my HW does not generate an in-band status. >>> AFAIK, it's >>> a PHY that aggregates 4xSGMIIs to 1xQSGMII ; the MAC side of the PHY >>> (with >>> inband status) is connected to the switch through QSGMII, and in this >>> context >>> we are on the media side of the PHY. >> >>> https://lkml.org/lkml/2015/7/10/206 >>> >>> This patch introduces the new boolean property 'autoneg' that allows >>> the user to request the auto-negotiation explicitly. >> The implementation looks better, but the name might still be slightly >> controversial. I would go with "use-in-band-status" which is more >> strictly defined than "autoneg" which could mean anything and everything. >> >> What do you think? > I actually think autoneg is a bit better. > > - Autonegotiation is a widely used and known term: > https://en.wikipedia.org/wiki/Autonegotiation > And who knows what in-band status is? You and I apparently do because otherwise you would not have ran into this problem and more generally, anyone having some mild exposure to the (S|R)GMII protocols should at some point, but that is a pointless argument. > And, more importantly, who knows what is it used for? > Who even knows it is used for autonegotiation? It is not about what do people know most, it is about being accurate and specific. > > - When we set autoneg for fixed-link, we basically just > say "no MDIO here, but please do autoneg by any other > means, if possible". I agree with this. > > - in-band status is an implementation delail, and it is > specific to a particular protocols. If you request the > in-band status for some protocol that doesn't support > it, perhaps you should get -EINVAL, because such a > config makes no sense. With autonegotiation, the rules > are not that strict: it can be "unimplemented", which doesn't > necessary mean nonsense in the config. So by specifying "autoneg", you are not specific about the kind of auto-negotiation protocol available, which is precisely my point: you need to go down to that level of detail for this to be useful. So maybe something like: autoneg = "in-band-status" would actually be a better thing in terms of description because then you would tell what can be made available/working? > > - autonegotiation is a wider term, and may be implemented > by some other means than the in-band status (which is > probably impossible for a fixed-link though). > > - In the terms that the driver uses, it is autonegotiation, eg > MVNETA_GMAC_AUTONEG_CONFIG. And when you go down > the implementation details, you see MVNETA_GMAC_INBAND_AN_ENABLE, > which is just one AN bit of many. But arguably, there could be another auto-negotiation method, which is not in-band status related, which means that you would need a way to distinguish between using in-band status, or using something else or nothing, would not you? > > So I really would prefer to keep things as is. > But if you insist, I can rename, but there will still be no > -EINVAL checks for obviously wrong configs.
10.07.2015 23:39, Florian Fainelli пишет: >> - in-band status is an implementation delail, and it is >> specific to a particular protocols. If you request the >> in-band status for some protocol that doesn't support >> it, perhaps you should get -EINVAL, because such a >> config makes no sense. With autonegotiation, the rules >> are not that strict: it can be "unimplemented", which doesn't >> necessary mean nonsense in the config. > So by specifying "autoneg", you are not specific about the kind of > auto-negotiation protocol available, which is precisely my point: you > need to go down to that level of detail for this to be useful. So maybe > something like: > > autoneg = "in-band-status" would actually be a better thing in terms of > description because then you would tell what can be made available/working? I would agree with this if your argument below is true (see below). >> - autonegotiation is a wider term, and may be implemented >> by some other means than the in-band status (which is >> probably impossible for a fixed-link though). >> >> - In the terms that the driver uses, it is autonegotiation, eg >> MVNETA_GMAC_AUTONEG_CONFIG. And when you go down >> the implementation details, you see MVNETA_GMAC_INBAND_AN_ENABLE, >> which is just one AN bit of many. > But arguably, there could be another auto-negotiation method, which is > not in-band status related, which means that you would need a way to > distinguish between using in-band status, or using something else or > nothing, would not you? "something else" is a big question here. Can you think of _any_ other way that is both not an MDIO (suits to fixed-link) and not an in-band? If the answer is yes (even theoretically), then autoneg = "in-band" | "off" may make sense. Otherwise boolean just looks enough. If we would implement autoneg outside of the fixed-link, then its semantic would likely be autoneg = "mdio" | "in-band" | "off" But the fact that we put it under fixed-link where only a single AN possibility exist, may probably be underlined by a semantic specific to fixed-link. One may also argue that autoneg = "any-possible-autoneg-that-works" is better than specifying it explicitly, which is exactly what the boolean does. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 10/07/15 14:02, Stas Sergeev wrote: > 10.07.2015 23:39, Florian Fainelli пишет: >>> - in-band status is an implementation delail, and it is >>> specific to a particular protocols. If you request the >>> in-band status for some protocol that doesn't support >>> it, perhaps you should get -EINVAL, because such a >>> config makes no sense. With autonegotiation, the rules >>> are not that strict: it can be "unimplemented", which doesn't >>> necessary mean nonsense in the config. >> So by specifying "autoneg", you are not specific about the kind of >> auto-negotiation protocol available, which is precisely my point: you >> need to go down to that level of detail for this to be useful. So maybe >> something like: >> >> autoneg = "in-band-status" would actually be a better thing in terms of >> description because then you would tell what can be made >> available/working? > I would agree with this if your argument below is true (see below). > >>> - autonegotiation is a wider term, and may be implemented >>> by some other means than the in-band status (which is >>> probably impossible for a fixed-link though). >>> >>> - In the terms that the driver uses, it is autonegotiation, eg >>> MVNETA_GMAC_AUTONEG_CONFIG. And when you go down >>> the implementation details, you see MVNETA_GMAC_INBAND_AN_ENABLE, >>> which is just one AN bit of many. >> But arguably, there could be another auto-negotiation method, which is >> not in-band status related, which means that you would need a way to >> distinguish between using in-band status, or using something else or >> nothing, would not you? > "something else" is a big question here. > Can you think of _any_ other way that is both not an MDIO > (suits to fixed-link) and not an in-band? Yes, I could think about I2C or SPI PHYs that you could use alongside an Ethernet controller that would qualify for out-of-band, not in-band, yet could still provide auto-negotiation. You may have special hardware with such a SPI or I2C controller which provides automatic decoding of the auto-neg registers. Have not looked at e.g: SFP form factors or fiber links, but they could also have additional out-of-band type of auto-negotiation available. > If the answer is yes (even theoretically), then > autoneg = "in-band" | "off" > may make sense. Otherwise boolean just looks enough. I think the answer is yes. > If we would implement autoneg outside of the fixed-link, > then its semantic would likely be > autoneg = "mdio" | "in-band" | "off" > But the fact that we put it under fixed-link where only a > single AN possibility exist, may probably be underlined by > a semantic specific to fixed-link. Right, if auto-negotiation was defined outside of fixed-link, that is indeed how I would also specify this. > > One may also argue that > autoneg = "any-possible-autoneg-that-works" is better than > specifying it explicitly, which is exactly what the boolean does. I prefer excess of information rather than lack of information, because you can always choose what to do with it. Especially when it comes to Device Tree, plan carefully :)
11.07.2015 03:22, Florian Fainelli пишет: > On 10/07/15 14:02, Stas Sergeev wrote: >> 10.07.2015 23:39, Florian Fainelli пишет: >>>> - in-band status is an implementation delail, and it is >>>> specific to a particular protocols. If you request the >>>> in-band status for some protocol that doesn't support >>>> it, perhaps you should get -EINVAL, because such a >>>> config makes no sense. With autonegotiation, the rules >>>> are not that strict: it can be "unimplemented", which doesn't >>>> necessary mean nonsense in the config. >>> So by specifying "autoneg", you are not specific about the kind of >>> auto-negotiation protocol available, which is precisely my point: you >>> need to go down to that level of detail for this to be useful. So maybe >>> something like: >>> >>> autoneg = "in-band-status" would actually be a better thing in terms of >>> description because then you would tell what can be made >>> available/working? >> I would agree with this if your argument below is true (see below). >> >>>> - autonegotiation is a wider term, and may be implemented >>>> by some other means than the in-band status (which is >>>> probably impossible for a fixed-link though). >>>> >>>> - In the terms that the driver uses, it is autonegotiation, eg >>>> MVNETA_GMAC_AUTONEG_CONFIG. And when you go down >>>> the implementation details, you see MVNETA_GMAC_INBAND_AN_ENABLE, >>>> which is just one AN bit of many. >>> But arguably, there could be another auto-negotiation method, which is >>> not in-band status related, which means that you would need a way to >>> distinguish between using in-band status, or using something else or >>> nothing, would not you? >> "something else" is a big question here. >> Can you think of _any_ other way that is both not an MDIO >> (suits to fixed-link) and not an in-band? > Yes, I could think about I2C or SPI PHYs that you could use alongside an > Ethernet controller that would qualify for out-of-band, not in-band, yet > could still provide auto-negotiation. You may have special hardware with > such a SPI or I2C controller which provides automatic decoding of the > auto-neg registers. Have not looked at e.g: SFP form factors or fiber > links, but they could also have additional out-of-band type of > auto-negotiation available. > >> If the answer is yes (even theoretically), then >> autoneg = "in-band" | "off" >> may make sense. Otherwise boolean just looks enough. > I think the answer is yes. > >> If we would implement autoneg outside of the fixed-link, >> then its semantic would likely be >> autoneg = "mdio" | "in-band" | "off" >> But the fact that we put it under fixed-link where only a >> single AN possibility exist, may probably be underlined by >> a semantic specific to fixed-link. > Right, if auto-negotiation was defined outside of fixed-link, that is > indeed how I would also specify this. Hmm, okey. But then this all doesn't fit into a fixed-link. The inband autoneg is a very small xtension, it only allows to notify MAC about some changes on the other end, but never control such changes, so from some POV it is still pretty much fixed. And it also built into the protocols that fixed-link already use, so that looked like a natural xtension to me. But if there are so many possible ways to abuse fixed-link making it _fully managed_, I am really starting to think about the possibility of defining the autoneg outside of it, and leave the poor fixed-link alone. The patch will be bigger, but... what do you think? This will of course first require defining the fixed-link in the docs more strictly, as currently it is (vaguely) defined as "non-MDIO", which leaves a lot to speculate and abuse. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/devicetree/bindings/net/fixed-link.txt b/Documentation/devicetree/bindings/net/fixed-link.txt index 82bf7e0..e2959a8 100644 --- a/Documentation/devicetree/bindings/net/fixed-link.txt +++ b/Documentation/devicetree/bindings/net/fixed-link.txt @@ -9,8 +9,12 @@ Such a fixed link situation is described by creating a 'fixed-link' sub-node of the Ethernet MAC device node, with the following properties: +* 'autoneg' (boolean, optional), to enable the auto-negotiation of link + state. Auto-negotiation is MII protocol, HW and driver-specific and is + not supported in many cases, so use it only when you know what you do. * 'speed' (integer, mandatory), to indicate the link speed. Accepted - values are 10, 100 and 1000 + values are 10, 100 and 1000. If the auto-negotiation is enabled, + 'speed' may not be set. It will then be auto-negotiated, if possible. * 'full-duplex' (boolean, optional), to indicate that full duplex is used. When absent, half duplex is assumed. * 'pause' (boolean, optional), to indicate that pause should be diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c index 1bd4305..12b2ede 100644 --- a/drivers/of/of_mdio.c +++ b/drivers/of/of_mdio.c @@ -280,6 +280,22 @@ bool of_phy_is_fixed_link(struct device_node *np) } EXPORT_SYMBOL(of_phy_is_fixed_link); +bool of_phy_is_autoneg_link(struct device_node *np) +{ + struct device_node *dn; + bool ret; + + dn = of_get_child_by_name(np, "fixed-link"); + if (!dn) + return false; + + ret = of_property_read_bool(dn, "autoneg"); + + of_node_put(dn); + return ret; +} +EXPORT_SYMBOL(of_phy_is_autoneg_link); + int of_phy_register_fixed_link(struct device_node *np) { struct fixed_phy_status status = {}; @@ -291,10 +307,13 @@ int of_phy_register_fixed_link(struct device_node *np) /* New binding */ fixed_link_node = of_get_child_by_name(np, "fixed-link"); if (fixed_link_node) { - status.link = 1; + bool autoneg = of_property_read_bool(fixed_link_node, + "autoneg"); + status.link = !autoneg; status.duplex = of_property_read_bool(fixed_link_node, "full-duplex"); - if (of_property_read_u32(fixed_link_node, "speed", &status.speed)) + if (of_property_read_u32(fixed_link_node, "speed", + &status.speed) != 0 && !autoneg) return -EINVAL; status.pause = of_property_read_bool(fixed_link_node, "pause"); status.asym_pause = of_property_read_bool(fixed_link_node, diff --git a/include/linux/of_mdio.h b/include/linux/of_mdio.h index d449018..647f348 100644 --- a/include/linux/of_mdio.h +++ b/include/linux/of_mdio.h @@ -65,6 +65,7 @@ static inline struct mii_bus *of_mdio_find_bus(struct device_node *mdio_np) #if defined(CONFIG_OF) && defined(CONFIG_FIXED_PHY) extern int of_phy_register_fixed_link(struct device_node *np); extern bool of_phy_is_fixed_link(struct device_node *np); +extern bool of_phy_is_autoneg_link(struct device_node *np); #else static inline int of_phy_register_fixed_link(struct device_node *np) { @@ -74,6 +75,10 @@ static inline bool of_phy_is_fixed_link(struct device_node *np) { return false; } +static inline bool of_phy_is_autoneg_link(struct device_node *np) +{ + return false; +} #endif
Currently for fixed-link the MAC driver decides whether to use the link status auto-negotiation or not. Unfortunately the auto-negotiation may not work when expected by the MAC driver. Sebastien Rannou explains: << Yes, I confirm that my HW does not generate an in-band status. AFAIK, it's a PHY that aggregates 4xSGMIIs to 1xQSGMII ; the MAC side of the PHY (with inband status) is connected to the switch through QSGMII, and in this context we are on the media side of the PHY. >> https://lkml.org/lkml/2015/7/10/206 This patch introduces the new boolean property 'autoneg' that allows the user to request the auto-negotiation explicitly. Signed-off-by: Stas Sergeev <stsp@users.sourceforge.net> CC: Rob Herring <robh+dt@kernel.org> CC: Pawel Moll <pawel.moll@arm.com> CC: Mark Rutland <mark.rutland@arm.com> CC: Ian Campbell <ijc+devicetree@hellion.org.uk> CC: Kumar Gala <galak@codeaurora.org> CC: Florian Fainelli <f.fainelli@gmail.com> CC: Grant Likely <grant.likely@linaro.org> CC: devicetree@vger.kernel.org CC: linux-kernel@vger.kernel.org CC: netdev@vger.kernel.org --- .../devicetree/bindings/net/fixed-link.txt | 6 +++++- drivers/of/of_mdio.c | 23 ++++++++++++++++++++-- include/linux/of_mdio.h | 5 +++++ 3 files changed, 31 insertions(+), 3 deletions(-)