On Wed, 26 Jun 2019 at 00:53, Russell King - ARM Linux admin <li...@armlinux.org.uk> wrote: > > On Tue, Jun 25, 2019 at 11:24:01PM +0300, Vladimir Oltean wrote: > > Hi Russell, > > > > On 6/24/19 6:39 PM, Russell King - ARM Linux admin wrote: > > > This should be removed - state->link is not for use in mac_config. > > > Even in fixed mode, the link can be brought up/down by means of a > > > gpio, and this should be dealt with via the mac_link_* functions. > > > > > > > What do you mean exactly that state->link is not for use, is that true in > > general? > > Yes. mac_config() should not touch it; it is not always in a defined > state. For example, if you set modes via ethtool (the > ethtool_ksettings_set API) then state->link will probably contain > zero irrespective of the true link state. >
Experimentally, state->link is zero at the same time as state->speed is -1, so just ignoring !state->link made sense. This is not in-band AN. What is your suggestion? Should I proceed to try and configure the MAC for SPEED_UNKNOWN? > It exists in this structure because it was convenient to just use one > structure to store all the link information in various parts of the > code, and when requesting the negotiated in-band MAC configuration. > > I've come to the conclusion that that decision was a mistake, based > on patches such as the above mistakenly thinking that everything in > the state structure is fair game. I've since updated the docs to > explicitly spell it out, but I'm also looking at the feasibility of > changing the mac_config() interface entirely - splitting it into two > (mac_config_fixed() and mac_config_inband()) and passing only the > appropriate parameters to each. > > However, having looked at that, I think such a change will make some > MAC drivers quite a bit more complicated - having all the config > steps in one method appears to make the configuration of MAC drivers > easier (eg, mvneta, mvpp2.) > > > In drivers/net/dsa/sja1105/sja1105_main.c, if I remove the "if > > (!state->link)" guard, I see PHYLINK calls with a SPEED_UNKNOWN argument for > > ports that are BR_STATE_DISABLED. Is that normal? > > This looks like another driver which has been converted to phylink > without my review; I certainly wasn't aware of it. It gets a few > things wrong, such as: > > 1) not checking state->interface in the validate callback - so it > is basically saying that it can support any PHY interface mode > that the kernel happens to support. > Partially true. It does check the DT bindings for supported MII modes in sja1105_init_mii_settings (for fundamental reasons... the switch expects an 'all-in-one' configuration buffer with the operating modes of all MACs - don't ask me to delay the uploading of this static config until all ports collected their interface_mode from phylink via the mac_config callback - it's a deadlock). It is a gigabit switch with MII/RMII/RGMII MACs - I have never seen any PHY wired for these modes that can change system interface type. > 2) if phylink is configured to use in-band, then state->speed is > undefined; this driver will fail. (If folk don't want to support > that, we ought to have a way to tell phylink to reject anything > that attempts to set it to in-band mode!) > Ok. > 3) it doesn't implement phylink_mac_link_state DSA ops, so it doesn't > support SGMII or 802.3z phy interface modes (see 1). > No, it doesn't. Some odd switch in this device family supports SGMII on 1 of its ports, however I haven't put my hands on it. When I do I'll add checks for strange scenarios, like connecting it to an Aquantia PHY that can switch between SGMII and USXGMII (although why would anyone pair a 10G capable PHY to a 1G capable MAC...) > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up > According to speedtest.net: 11.9Mbps down 500kbps up Thanks, -Vladimir
