Messages in this thread |  | | Date | Mon, 30 Nov 2020 15:15:56 +0100 | From | Steen Hegelund <> | Subject | Re: [RFC PATCH 2/3] net: sparx5: Add Sparx5 switchdev driver |
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On 29.11.2020 10:52, Russell King - ARM Linux admin wrote: >EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > >On Sat, Nov 28, 2020 at 10:28:28PM +0000, Russell King - ARM Linux admin wrote: >> On Sat, Nov 28, 2020 at 08:06:16PM +0100, Andrew Lunn wrote: >> > > +static void sparx5_phylink_mac_config(struct phylink_config *config, >> > > + unsigned int mode, >> > > + const struct phylink_link_state *state) >> > > +{ >> > > + struct sparx5_port *port = netdev_priv(to_net_dev(config->dev)); >> > > + struct sparx5_port_config conf; >> > > + int err = 0; >> > > + >> > > + conf = port->conf; >> > > + conf.autoneg = state->an_enabled; >> > > + conf.pause = state->pause; >> > > + conf.duplex = state->duplex; >> > > + conf.power_down = false; >> > > + conf.portmode = state->interface; >> > > + >> > > + if (state->speed == SPEED_UNKNOWN) { >> > > + /* When a SFP is plugged in we use capabilities to >> > > + * default to the highest supported speed >> > > + */ >> > >> > This looks suspicious. >> >> Yes, it looks highly suspicious. The fact that >> sparx5_phylink_mac_link_up() is empty, and sparx5_phylink_mac_config() >> does all the work suggests that this was developed before the phylink >> re-organisation, and this code hasn't been updated for it. >> >> Any new code for the kernel really ought to be updated for the new >> phylink methodology before it is accepted. >> >> Looking at sparx5_port_config(), it also seems to use >> PHY_INTERFACE_MODE_1000BASEX for both 1000BASE-X and 2500BASE-X. All >> very well for the driver to do that internally, but it's confusing >> when it comes to reviewing this stuff, especially when people outside >> of the driver (such as myself) reviewing it need to understand what's >> going on with the configuration. >
Hi Russell,
>There are other issues too. > >Looking at sparx5_get_1000basex_status(), we have: > > + status->link = DEV2G5_PCS1G_LINK_STATUS_LINK_STATUS_GET(value) | > + DEV2G5_PCS1G_LINK_STATUS_SYNC_STATUS_GET(value); >
>Why is the link status the logical OR of these?
Oops: It should have been AND. Well spotted.
> > + if ((lp_abil >> 8) & 1) /* symmetric pause */ > + status->pause = MLO_PAUSE_RX | MLO_PAUSE_TX; > + if (lp_abil & (1 << 7)) /* asymmetric pause */ > + status->pause |= MLO_PAUSE_RX; > >is actually wrong, and I see I need to improve the documentation for >mac_pcs_get_state(). The intention in the documentation was concerning >hardware that indicated the _resolved_ status of pause modes. It was >not intended that drivers resolve the pause modes themselves. > >Even so, the above is still wrong; it takes no account of what is being >advertised at the local end. If one looks at the implementation in >phylink_decode_c37_word(), one will notice there is code to deal with >this. > >I think we ought to make phylink_decode_c37_word() and >phylink_decode_sgmii_word() public functions, and then this driver can >use these helpers to decode the link partner advertisement to the >phylink state.
Should I remove the current implementation and use something like what is in phylink_decode_c37_word() and phylink_decode_sgmii_word() in the meantime?
> >Does the driver need to provide an ethtool .get_link function? That >seems to bypass phylink. Why can't ethtool_op_get_link() be used?
I think that I tried that earlier, but ran into problems. I better revisit this, and try out your suggestion.
> >I think if ethtool_op_get_link() is used, we then have just one caller >for sparx5_get_port_status(), which means "struct sparx5_port_status" >can be eliminated and the code cleaned up to use the phylink decoding >helpers. > >-- >RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ >FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
Thanks for your comments.
BR Steen
--------------------------------------- Steen Hegelund steen.hegelund@microchip.com
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