Re: [PATCH 07/14] net: axienet: Fix SGMII support
From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Date: 2020-01-10 15:04:24
Also in:
linux-arm-kernel, lkml
On Fri, Jan 10, 2020 at 02:20:38PM +0000, Andre Przywara wrote:
On Fri, 10 Jan 2020 15:04:15 +0100 Andrew Lunn [off-list ref] wrote: Hi Andrew,quoted
On Fri, Jan 10, 2020 at 11:54:08AM +0000, Andre Przywara wrote:quoted
With SGMII, the MAC and the PHY can negotiate the link speed between themselves, without the host needing to mediate between them. Linux recognises this, and will call phylink's mac_config with the speed member set to SPEED_UNKNOWN (-1). Currently the axienet driver will bail out and complain about an unsupported link speed. Teach axienet's mac_config callback to leave the MAC's speed setting alone if the requested speed is SPEED_UNKNOWN.Hi Andre Is there an interrupt when SGMII signals a change in link state? If so, you should call phylink_mac_change().Good point. The doc describes a "Auto-Negotiation Complete" interrupt status bit, which signal that " ... auto-negotiation of the SGMII or 1000BASE-X interface has completed."
It depends what they mean by "Auto-negotiation complete" in SGMII. SGMII can complete the handshake, yet the config_reg word indicate link down. If such an update causes an "Auto-negotiation complete" interrupt, then that's sufficient. However, looking at axienet_mac_pcs_get_state(), that is just reading back what the MAC was set to in axienet_mac_config(), which is not how this is supposed to work. axienet_mac_pcs_get_state() is supposed to get the results of the SGMII/1000BASE-X "negotiation". That also needs to be fixed. -- 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