On Wed, Jun 19, 2019 at 11:23:01AM +0000, Parshuram Raju Thombare wrote: > >From: Russell King - ARM Linux admin <li...@armlinux.org.uk> > > > >On Wed, Jun 19, 2019 at 09:40:46AM +0100, Parshuram Thombare wrote: > > > >> This patch add support for SGMII interface) and > > > >> 2.5Gbps MAC in Cadence ethernet controller driver. > > >> switch (state->interface) { > > > >> + case PHY_INTERFACE_MODE_SGMII: > > > >> + if (bp->caps & MACB_CAPS_GIGABIT_MODE_AVAILABLE) > > > >> + phylink_set(mask, 2500baseT_Full); > > > > > > > >This doesn't look correct to me. SGMII as defined by Cisco only > >supports 1G, 100M and 10M speeds, not 2.5G. > > Cadence MAC support 2.5G SGMII by using higher clock frequency.
Ok, so why not set 2.5GBASE-X too? Does the MAC handle auto-detecting the SGMII/BASE-X speed itself or does it need to be programmed? If it needs to be programmed, you need additional handling in the validate callback to deal with that. > >> + case PHY_INTERFACE_MODE_2500BASEX: > > > >> + if (bp->caps & MACB_CAPS_GIGABIT_MODE_AVAILABLE) > > > >> + phylink_set(mask, 2500baseX_Full); > > > >> + /* fallthrough */ > > > >> + case PHY_INTERFACE_MODE_1000BASEX: > > > >> + if (bp->caps & MACB_CAPS_GIGABIT_MODE_AVAILABLE) > > > >> + phylink_set(mask, 1000baseX_Full); > > > >> + break; > > > > > > > >Please see how other drivers which use phylink deal with the validate() > >format, and please read the phylink documentation: > > > > * Note that the PHY may be able to transform from one connection > > * technology to another, so, eg, don't clear 1000BaseX just > > * because the MAC is unable to BaseX mode. This is more about > > * clearing unsupported speeds and duplex settings. > > > > There are some configs used in this driver which limits MAC speed. > Above checks just to make sure this use case does not break. That's not what I'm saying. By way of example, you're offering 1000BASE-T just because the MAC connection supports it. However, the MAC doesn't _actually_ support 1000BASE-T, it supports a connection to a PHY that _happens_ to convert the MAC connection to 1000BASE-T. It could equally well convert the MAC connection to 1000BASE-X. So, only setting 1000BASE-X when you have a PHY connection using 1000BASE-X is fundamentally incorrect. For example, you could have a MAC <-> PHY link using standard 1.25Gbps SGMII, and the PHY offers 1000BASE-T _and_ 1000BASE-X connections on a first-link-up basis. An example of a PHY that does this are the Marvell 1G PHYs (eg, 88E151x). This point is detailed in the PHYLINK documentation, which I quoted above. > >> @@ -506,18 +563,26 @@ static void gem_mac_config(struct phylink_config > >*pl_config, unsigned int mode, > >> switch (state->speed) { > >> + case SPEED_2500: > >> + gem_writel(bp, NCFGR, GEM_BIT(GBE) | > >> + gem_readl(bp, NCFGR)); > >> } > >> - macb_or_gem_writel(bp, NCFGR, reg); > >> > >> bp->speed = state->speed; > >> bp->duplex = state->duplex; > > > > > > > >This is not going to work for 802.3z nor SGMII properly when in-band > >negotiation is used. We don't know ahead of time what the speed and > >duplex will be. Please see existing drivers for examples showing > >how mac_config() should be implemented (there's good reason why its > >laid out as it is in those drivers.) > > > Ok, Here I will configure MAC only for FIXED and PHY mode. As you are not the only one who has made this error, I'm considering splitting mac_config() into mac_config_fixed() and mac_config_inband() so that it's clearer what is required. Maybe even taking separate structures so that it's impossible to access members that should not be used. -- 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