Messages in this thread |  | | Date | Sun, 29 Nov 2020 10:52:45 +0000 | From | Russell King - ARM Linux admin <> | Subject | Re: [RFC PATCH 2/3] net: sparx5: Add Sparx5 switchdev driver |
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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.
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?
+ 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.
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 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!
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