| Message ID | 581CA300.1060609@laposte.net |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Fri, Nov 04, 2016 at 04:02:24PM +0100, Sebastian Frias wrote: > The delay can be applied at PHY or MAC level, but since > PHY drivers will apply the delay at PHY level when using > one of the "internal delay" declinations of RGMII mode > (like PHY_INTERFACE_MODE_RGMII_TXID), applying it again > at MAC level causes issues. > > Signed-off-by: Sebastian Frias <sf84@laposte.net> > --- > drivers/net/ethernet/aurora/nb8800.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/aurora/nb8800.c b/drivers/net/ethernet/aurora/nb8800.c > index b59aa35..d2855c9 100644 > --- a/drivers/net/ethernet/aurora/nb8800.c > +++ b/drivers/net/ethernet/aurora/nb8800.c > @@ -1282,7 +1282,7 @@ static int nb8800_tangox_init(struct net_device *dev) > break; > > case PHY_INTERFACE_MODE_RGMII_TXID: > - pad_mode = PAD_MODE_RGMII | PAD_MODE_GTX_CLK_DELAY; > + pad_mode = PAD_MODE_RGMII; > break; How many boards use this Ethernet driver? How many boards are your potentially breaking, because they need this delay? I guess it is a small number, because doesn't it require the PHY is also broken, not adding a delay when it should? Andrew
Sebastian Frias <sf84@laposte.net> writes: > The delay can be applied at PHY or MAC level, but since > PHY drivers will apply the delay at PHY level when using > one of the "internal delay" declinations of RGMII mode > (like PHY_INTERFACE_MODE_RGMII_TXID), applying it again > at MAC level causes issues. The Broadcom GENET driver does the same thing. > Signed-off-by: Sebastian Frias <sf84@laposte.net> > --- > drivers/net/ethernet/aurora/nb8800.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/aurora/nb8800.c b/drivers/net/ethernet/aurora/nb8800.c > index b59aa35..d2855c9 100644 > --- a/drivers/net/ethernet/aurora/nb8800.c > +++ b/drivers/net/ethernet/aurora/nb8800.c > @@ -1282,7 +1282,7 @@ static int nb8800_tangox_init(struct net_device *dev) > break; > > case PHY_INTERFACE_MODE_RGMII_TXID: > - pad_mode = PAD_MODE_RGMII | PAD_MODE_GTX_CLK_DELAY; > + pad_mode = PAD_MODE_RGMII; > break; > > default: > -- > 1.7.11.2 If this change is correct (and I'm not convinced it is), that case should be merged with the one above it and PHY_INTERFACE_MODE_RGMII_RXID added as well.
Andrew Lunn <andrew@lunn.ch> writes: > On Fri, Nov 04, 2016 at 04:02:24PM +0100, Sebastian Frias wrote: >> The delay can be applied at PHY or MAC level, but since >> PHY drivers will apply the delay at PHY level when using >> one of the "internal delay" declinations of RGMII mode >> (like PHY_INTERFACE_MODE_RGMII_TXID), applying it again >> at MAC level causes issues. If this is correct, most of the PHY drivers are broken. >> Signed-off-by: Sebastian Frias <sf84@laposte.net> >> --- >> drivers/net/ethernet/aurora/nb8800.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/ethernet/aurora/nb8800.c b/drivers/net/ethernet/aurora/nb8800.c >> index b59aa35..d2855c9 100644 >> --- a/drivers/net/ethernet/aurora/nb8800.c >> +++ b/drivers/net/ethernet/aurora/nb8800.c >> @@ -1282,7 +1282,7 @@ static int nb8800_tangox_init(struct net_device *dev) >> break; >> >> case PHY_INTERFACE_MODE_RGMII_TXID: >> - pad_mode = PAD_MODE_RGMII | PAD_MODE_GTX_CLK_DELAY; >> + pad_mode = PAD_MODE_RGMII; >> break; > > How many boards use this Ethernet driver? How many boards are your > potentially breaking, because they need this delay? > > I guess it is a small number, because doesn't it require the PHY is > also broken, not adding a delay when it should? What if the PHY doesn't have that option?
Hi Andrew, On 11/04/2016 04:11 PM, Andrew Lunn wrote: > On Fri, Nov 04, 2016 at 04:02:24PM +0100, Sebastian Frias wrote: >> The delay can be applied at PHY or MAC level, but since >> PHY drivers will apply the delay at PHY level when using >> one of the "internal delay" declinations of RGMII mode >> (like PHY_INTERFACE_MODE_RGMII_TXID), applying it again >> at MAC level causes issues. >> >> Signed-off-by: Sebastian Frias <sf84@laposte.net> >> --- >> drivers/net/ethernet/aurora/nb8800.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/ethernet/aurora/nb8800.c b/drivers/net/ethernet/aurora/nb8800.c >> index b59aa35..d2855c9 100644 >> --- a/drivers/net/ethernet/aurora/nb8800.c >> +++ b/drivers/net/ethernet/aurora/nb8800.c >> @@ -1282,7 +1282,7 @@ static int nb8800_tangox_init(struct net_device *dev) >> break; >> >> case PHY_INTERFACE_MODE_RGMII_TXID: >> - pad_mode = PAD_MODE_RGMII | PAD_MODE_GTX_CLK_DELAY; >> + pad_mode = PAD_MODE_RGMII; >> break; > > How many boards use this Ethernet driver? How many boards are your > potentially breaking, because they need this delay? > This part is specific to the Tango architecture, as noted by the function name "nb8800_tangox_init". Also the register used here is Sigma-specific (i.e.: not related to the Aurora VLSI MAC, "au-nb8800") The thing is that without this patch if we set phy-connection-type="rgmii-txid" on the DT, then both, the PHY and the MAC, will apply the delay. Best regards, Sebastian > I guess it is a small number, because doesn't it require the PHY is > also broken, not adding a delay when it should? > > Andrew >
Hi Måns, On 11/04/2016 04:18 PM, Måns Rullgård wrote: > Sebastian Frias <sf84@laposte.net> writes: > >> The delay can be applied at PHY or MAC level, but since >> PHY drivers will apply the delay at PHY level when using >> one of the "internal delay" declinations of RGMII mode >> (like PHY_INTERFACE_MODE_RGMII_TXID), applying it again >> at MAC level causes issues. > > The Broadcom GENET driver does the same thing. > Well, I don't know who uses that driver, or why they did it that way. However, with the current code and DT bindings, if one requires the delay, phy-connection-type="rgmii-txid" must be set. But when doing so, both the Atheros 8035 and the Aurora NB8800 drivers will apply the delay. I think a better way of dealing with this is that both, PHY and MAC drivers exchange information so that the delay is applied only once. I can see how to do that in another patch set. >> Signed-off-by: Sebastian Frias <sf84@laposte.net> >> --- >> drivers/net/ethernet/aurora/nb8800.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/ethernet/aurora/nb8800.c b/drivers/net/ethernet/aurora/nb8800.c >> index b59aa35..d2855c9 100644 >> --- a/drivers/net/ethernet/aurora/nb8800.c >> +++ b/drivers/net/ethernet/aurora/nb8800.c >> @@ -1282,7 +1282,7 @@ static int nb8800_tangox_init(struct net_device *dev) >> break; >> >> case PHY_INTERFACE_MODE_RGMII_TXID: >> - pad_mode = PAD_MODE_RGMII | PAD_MODE_GTX_CLK_DELAY; >> + pad_mode = PAD_MODE_RGMII; >> break; >> >> default: >> -- >> 1.7.11.2 > > If this change is correct (and I'm not convinced it is), that case > should be merged with the one above it and PHY_INTERFACE_MODE_RGMII_RXID > added as well. > I can do a single patch. The reason I made two patches was that it was clear what this patch does, i.e.: do not apply the delay at MAC level, and what the subsequent patch does, i.e.: handle all RGMII declinations. Best regards, Sebastian
On 11/04/2016 08:36 AM, Sebastian Frias wrote: > Hi Måns, > > On 11/04/2016 04:18 PM, Måns Rullgård wrote: >> Sebastian Frias <sf84@laposte.net> writes: >> >>> The delay can be applied at PHY or MAC level, but since >>> PHY drivers will apply the delay at PHY level when using >>> one of the "internal delay" declinations of RGMII mode >>> (like PHY_INTERFACE_MODE_RGMII_TXID), applying it again >>> at MAC level causes issues. >> >> The Broadcom GENET driver does the same thing. >> > > Well, I don't know who uses that driver, or why they did it that way. I do use this driver and it works for me (tm), although I tested mostly with Broadcom PHYs and Ethernet switches, rarely with third party PHYs, but had that too, but all of that is in tree though, drivers/net/phy/broadcom.com, drivers/net/dsa/b53/ so feel free to "audit" that part of the code too. The configuration of the GENET port multiplexer requires us to specify how we want to align the clock and data, if we don't do that, and the PHY is also not agreeing with how its own delays should be configured, mayhem ensues, ranging from occasional transmit success, to high rates of CRC/FCS errors in best cases. I did verify that the settings were correct using a scope FWIW. > > However, with the current code and DT bindings, if one requires > the delay, phy-connection-type="rgmii-txid" must be set. Yes, and we would set it correctly for our Broadcom reference boards using this driver. > > But when doing so, both the Atheros 8035 and the Aurora NB8800 drivers > will apply the delay. > > I think a better way of dealing with this is that both, PHY and MAC > drivers exchange information so that the delay is applied only once. Exchange what information? The PHY device interface (phydev->interface) conveys the needed information for both entities. > > I can see how to do that in another patch set. > >>> Signed-off-by: Sebastian Frias <sf84@laposte.net> >>> --- >>> drivers/net/ethernet/aurora/nb8800.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/net/ethernet/aurora/nb8800.c b/drivers/net/ethernet/aurora/nb8800.c >>> index b59aa35..d2855c9 100644 >>> --- a/drivers/net/ethernet/aurora/nb8800.c >>> +++ b/drivers/net/ethernet/aurora/nb8800.c >>> @@ -1282,7 +1282,7 @@ static int nb8800_tangox_init(struct net_device *dev) >>> break; >>> >>> case PHY_INTERFACE_MODE_RGMII_TXID: >>> - pad_mode = PAD_MODE_RGMII | PAD_MODE_GTX_CLK_DELAY; >>> + pad_mode = PAD_MODE_RGMII; >>> break; >>> >>> default: >>> -- >>> 1.7.11.2 >> >> If this change is correct (and I'm not convinced it is), that case >> should be merged with the one above it and PHY_INTERFACE_MODE_RGMII_RXID >> added as well. >> > > I can do a single patch. > > The reason I made two patches was that it was clear what this patch > does, i.e.: do not apply the delay at MAC level, and what the subsequent > patch does, i.e.: handle all RGMII declinations. > > Best regards, > > Sebastian >
Florian Fainelli <f.fainelli@gmail.com> writes: > On 11/04/2016 08:36 AM, Sebastian Frias wrote: >> Hi Måns, >> >> On 11/04/2016 04:18 PM, Måns Rullgård wrote: >>> Sebastian Frias <sf84@laposte.net> writes: >>> >>>> The delay can be applied at PHY or MAC level, but since >>>> PHY drivers will apply the delay at PHY level when using >>>> one of the "internal delay" declinations of RGMII mode >>>> (like PHY_INTERFACE_MODE_RGMII_TXID), applying it again >>>> at MAC level causes issues. >>> >>> The Broadcom GENET driver does the same thing. >>> >> >> Well, I don't know who uses that driver, or why they did it that way. > > I do use this driver and it works for me (tm), although I tested mostly > with Broadcom PHYs and Ethernet switches, rarely with third party PHYs, > but had that too, but all of that is in tree though, > drivers/net/phy/broadcom.com, drivers/net/dsa/b53/ so feel free to > "audit" that part of the code too. > > The configuration of the GENET port multiplexer requires us to specify > how we want to align the clock and data, if we don't do that, and the > PHY is also not agreeing with how its own delays should be configured, > mayhem ensues, ranging from occasional transmit success, to high rates > of CRC/FCS errors in best cases. > > I did verify that the settings were correct using a scope FWIW. > >> >> However, with the current code and DT bindings, if one requires >> the delay, phy-connection-type="rgmii-txid" must be set. > > Yes, and we would set it correctly for our Broadcom reference boards > using this driver. > >> >> But when doing so, both the Atheros 8035 and the Aurora NB8800 drivers >> will apply the delay. >> >> I think a better way of dealing with this is that both, PHY and MAC >> drivers exchange information so that the delay is applied only once. > > Exchange what information? The PHY device interface (phydev->interface) > conveys the needed information for both entities. There doesn't seem to be any consensus among the drivers regarding where the delay should be applied. Since only a few drivers, MAC or PHY, act on this property, most combinations still work by chance. It is common for boards to set the delay at the PHY using external config pins so no software setup is required (although I have one Sigma based board that gets this wrong). I suspect if drivers/net/ethernet/broadcom/genet were used with one of the four PHY drivers that also set the delay based on this DT property, things would go wrong.
diff --git a/drivers/net/ethernet/aurora/nb8800.c b/drivers/net/ethernet/aurora/nb8800.c index b59aa35..d2855c9 100644 --- a/drivers/net/ethernet/aurora/nb8800.c +++ b/drivers/net/ethernet/aurora/nb8800.c @@ -1282,7 +1282,7 @@ static int nb8800_tangox_init(struct net_device *dev) break; case PHY_INTERFACE_MODE_RGMII_TXID: - pad_mode = PAD_MODE_RGMII | PAD_MODE_GTX_CLK_DELAY; + pad_mode = PAD_MODE_RGMII; break; default:
The delay can be applied at PHY or MAC level, but since PHY drivers will apply the delay at PHY level when using one of the "internal delay" declinations of RGMII mode (like PHY_INTERFACE_MODE_RGMII_TXID), applying it again at MAC level causes issues. Signed-off-by: Sebastian Frias <sf84@laposte.net> --- drivers/net/ethernet/aurora/nb8800.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)