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net: dsa: validate that DT nodes of shared ports have the properties …
…they need Russell King points out that the phylink_pcs conversion of DSA drivers he is working on is likely to break drivers, because of the movement of code that didn't use to depend on phylink towards phylink callbacks. One example is mv88e6xxx, where DSA and CPU ports are configured during mv88e6xxx_setup() -> mv88e6xxx_setup_port() (therefore outside of phylink). DSA was not always integrated with phylink, and when the early drivers were converted from platform data to the new DSA bindings, there was no information kept in the platform data structures about port link speeds, so as a result, there was no information translated into the first DT bindings. https://lore.kernel.org/all/YtXFtTsf++AeDm1l@lunn.ch/ DSA first became integrated with phylink for user ports, where the interpretation of a port OF node with lacking information is different. Then there was an initial attempt to integrate phylink with CPU and DSA ports as well (these have no net devices), which was fixed up by a workaround added in commit a20f997 ("net: dsa: Don't instantiate phylink for CPU/DSA ports unless needed"). The above workaround checks for the presence of phy-handle/fixed-link/ managed properties inside the OF nodes of CPU and DSA ports, and avoids registering phylink if they're missing. This is the state of things today, but what the workaround commit could have done better is that it didn't stop the proliferation of port OF nodes with lacking information. Today we have drivers introduced years after the phylink migration of CPU/DSA ports, and yet we're still not completely sure whether all new drivers use phylink, because this depends on dynamic information (DT blob, which may very well not be upstream, because why would it). Driver maintainers may even be unaware about the fact that not specifying fixed-link/phy-handle for CPU/DSA ports is legal for the old drivers, and even works. In this change we add central validation in DSA for the OF properties required by phylink, in an attempt to sanitize the environment for future driver writers, and as much as possible for existing driver maintainers. Technically no driver except sja1105 and felix (partially) validates these properties, but perhaps due to subtle reasons, some of the other existing drivers may not actually work properly with a port OF node that lacks a complete description. There isn't any way to know except by deleting the fixed-link (or phy-mode or both) on a CPU port and trying. There isn't a desire to make drivers that never worked start working with these DT blobs, but rather to eventually move all drivers towards using phylink on shared ports, including when the DT information is lacking. There is a parallel effort to artificially create a description for phylink for these ports; however it involves guesswork and may get things wrong. This is where this change comes in: drivers which do not opt out of strict validation do not need to concern themselves with how to artificially create the description, and how to configure themselves for the "maximum speed" mode. We can't fully know what is the situation with downstream DT blobs, but we can guess the overall trend by studying the DT blobs that were submitted upstream. If there are upstream blobs that have lacking descriptions, we take it as very likely that there are many more downstream blobs that do so too. If all upstream blobs have complete descriptions, we take that as a hint that the driver is a candidate for strict validation (considering that most bindings are copy-pasted). If there are no upstream DT blobs, we take the conservative route of skipping validation, unless the driver maintainer instructs us otherwise. The driver situation is as follows: mv88e6xxx ~~~~~~~~~ compatible strings: - marvell,mv88e6085 - marvell,mv88e6190 - marvell,mv88e6250 Device trees that have incomplete descriptions of CPU or DSA ports: arch/arm64/boot/dts/freescale/imx8mq-zii-ultra.dtsi - lacks phy-mode arch/arm64/boot/dts/marvell/cn9130-crb.dtsi - lacks phy-mode and fixed-link arch/arm/boot/dts/vf610-zii-ssmb-spu3.dts - lacks phy-mode arch/arm/boot/dts/kirkwood-mv88f6281gtw-ge.dts - lacks phy-mode arch/arm/boot/dts/vf610-zii-spb4.dts - lacks phy-mode arch/arm/boot/dts/vf610-zii-cfu1.dts - lacks phy-mode arch/arm/boot/dts/vf610-zii-dev-rev-c.dts - lacks phy-mode on CPU port, fixed-link on DSA ports arch/arm/boot/dts/vf610-zii-dev-rev-b.dts - lacks phy-mode on CPU port arch/arm/boot/dts/armada-381-netgear-gs110emx.dts - lacks phy-mode arch/arm/boot/dts/vf610-zii-scu4-aib.dts - lacks fixed-link on xgmii DSA ports and/or in-band-status on 2500base-x DSA ports, and phy-mode on CPU port arch/arm/boot/dts/imx6qdl-gw5904.dtsi - lacks phy-mode and fixed-link arch/arm/boot/dts/armada-385-clearfog-gtr-l8.dts - lacks phy-mode and fixed-link arch/arm/boot/dts/vf610-zii-ssmb-dtu.dts - lacks phy-mode arch/arm/boot/dts/kirkwood-dir665.dts - lacks phy-mode arch/arm/boot/dts/kirkwood-rd88f6281.dtsi - lacks phy-mode arch/arm/boot/dts/orion5x-netgear-wnr854t.dts - lacks phy-mode and fixed-link arch/arm/boot/dts/armada-388-clearfog.dts - lacks phy-mode arch/arm/boot/dts/armada-xp-linksys-mamba.dts - lacks phy-mode arch/arm/boot/dts/armada-385-linksys.dtsi - lacks phy-mode arch/arm/boot/dts/imx6q-b450v3.dts arch/arm/boot/dts/imx6q-b850v3.dts - has a phy-handle but not a phy-mode? arch/arm/boot/dts/armada-370-rd.dts - lacks phy-mode arch/arm/boot/dts/kirkwood-linksys-viper.dts - lacks phy-mode arch/arm/boot/dts/imx51-zii-rdu1.dts - lacks phy-mode arch/arm/boot/dts/imx51-zii-scu2-mezz.dts - lacks phy-mode arch/arm/boot/dts/imx6qdl-zii-rdu2.dtsi - lacks phy-mode arch/arm/boot/dts/armada-385-clearfog-gtr-s4.dts - lacks phy-mode and fixed-link Verdict: opt out of validation. ar9331 ~~~~~~ compatible strings: - qca,ar9331-switch 1 occurrence in mainline device trees, part of SoC dtsi (arch/mips/boot/dts/qca/ar9331.dtsi), description is not problematic. Verdict: opt into validation. qca8k ~~~~~ compatible strings: - qca,qca8327 - qca,qca8328 - qca,qca8334 - qca,qca8337 5 occurrences in mainline device trees, none of the descriptions are problematic. Verdict: opt into validation. hellcreek ~~~~~~~~~ compatible strings: - hirschmann,hellcreek-de1soc-r1 No occurrence in mainline device trees, we don't know. Verdict: opt out of validation. lan9303 ~~~~~~~ compatible strings: - smsc,lan9303-mdio - smsc,lan9303-i2c 1 occurrence in mainline device trees: arch/arm/boot/dts/imx53-kp-hsc.dts - no phy-mode, no fixed-link Verdict: opt out of validation. microchip ksz ~~~~~~~~~~~~~ compatible strings: - microchip,ksz8765 - microchip,ksz8794 - microchip,ksz8795 - microchip,ksz8863 - microchip,ksz8873 - microchip,ksz9477 - microchip,ksz9897 - microchip,ksz9893 - microchip,ksz9563 - microchip,ksz8563 - microchip,ksz9567 - microchip,lan9370 - microchip,lan9371 - microchip,lan9372 - microchip,lan9373 - microchip,lan9374 5 occurrences in mainline device trees, all descriptions are valid. But we had a snafu for the ksz8795 and ksz9477 drivers where the phy-mode property would be expected to be located directly under the 'switch' node rather than under a port OF node. It was fixed by commit edecfa9 ("net: dsa: microchip: look for phy-mode in port nodes"). The driver still has compatibility with the old DT blobs. The lan937x support was added later than the above snafu was fixed, and even though it has support for the broken DT blobs by virtue of sharing a common probing function, I'll take it that its DT blobs are correct. Verdict: opt lan937x into validation, and the others out. bcm_sf2 ~~~~~~~ compatible strings: - brcm,bcm4908-switch - brcm,bcm7445-switch-v4.0 - brcm,bcm7278-switch-v4.0 - brcm,bcm7278-switch-v4.8 A single occurrence in mainline (arch/arm64/boot/dts/broadcom/bcm4908/bcm4908.dtsi), part of a SoC dtsi, valid description. Verdict: opt into strict validation the switch we know, and opt out the ones we don't. ocelot ~~~~~~ compatible strings: - mscc,vsc9953-switch - felix (arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi) is a PCI device, has no compatible string 2 occurrences in mainline, both are part of SoC dtsi and complete. Verdict: opt into strict validation. mv88e6060 ~~~~~~~~~ compatible string: - marvell,mv88e6060 no occurrences in mainline, nobody knows anybody who uses it. Verdict: opt out of strict validation. xrs700x ~~~~~~~ compatible strings: - arrow,xrs7003e - arrow,xrs7003f - arrow,xrs7004e - arrow,xrs7004f no occurrences in mainline Verdict: opt out of strict validation. mt7530 ~~~~~~ compatible strings - mediatek,mt7621 - mediatek,mt7530 - mediatek,mt7531 Multiple occurrences in mainline device trees, one is part of an SoC dtsi (arch/mips/boot/dts/ralink/mt7621.dtsi), all descriptions are fine. Verdict: opt into strict validation. lantiq_gswip ~~~~~~~~~~~~ compatible strings: - lantiq,xrx200-gswip - lantiq,xrx300-gswip - lantiq,xrx330-gswip No occurrences in mainline device trees. Verdict: opt out of validation, because we don't know. vsc73xx ~~~~~~~ compatible strings: - vitesse,vsc7385 - vitesse,vsc7388 - vitesse,vsc7395 - vitesse,vsc7398 2 occurrences in mainline device trees, both descriptions are fine. Verdict: opt into validation. rzn1_a5psw ~~~~~~~~~~ compatible strings: - renesas,rzn1-a5psw One single occurrence, part of SoC dtsi (arch/arm/boot/dts/r9a06g032.dtsi), description is fine. Verdict: opt into validation. sja1105 ~~~~~~~ Driver already validates its port OF nodes in sja1105_parse_ports_node(). Verdict: opt into validation. realtek ~~~~~~~ compatible strings: - realtek,rtl8366rb - realtek,rtl8365mb 2 occurrences in mainline, both descriptions are fine, additionally rtl8365mb.c has a comment "The device tree firmware should also specify the link partner of the extension port - either via a fixed-link or other phy-handle." Verdict: opt into validation. b53 ~~~ compatible strings: - brcm,bcm5325 - brcm,bcm53115 - brcm,bcm53125 - brcm,bcm53128 - brcm,bcm5365 - brcm,bcm5389 - brcm,bcm5395 - brcm,bcm5397 - brcm,bcm5398 - brcm,bcm53010-srab - brcm,bcm53011-srab - brcm,bcm53012-srab - brcm,bcm53018-srab - brcm,bcm53019-srab - brcm,bcm5301x-srab - brcm,bcm11360-srab - brcm,bcm58522-srab - brcm,bcm58525-srab - brcm,bcm58535-srab - brcm,bcm58622-srab - brcm,bcm58623-srab - brcm,bcm58625-srab - brcm,bcm88312-srab - brcm,cygnus-srab - brcm,nsp-srab - brcm,omega-srab - brcm,bcm3384-switch - brcm,bcm6328-switch - brcm,bcm6368-switch - brcm,bcm63xx-switch I've found at least these mainline DT blobs with problems: arch/arm/boot/dts/bcm47094-linksys-panamera.dts - lacks phy-mode arch/arm/boot/dts/bcm47189-tenda-ac9.dts - lacks phy-mode and fixed-link arch/arm/boot/dts/bcm47081-luxul-xap-1410.dts arch/arm/boot/dts/bcm47081-luxul-xwr-1200.dts arch/arm/boot/dts/bcm47081-buffalo-wzr-600dhp2.dts - lacks phy-mode and fixed-link arch/arm/boot/dts/bcm47094-luxul-xbr-4500.dts arch/arm/boot/dts/bcm4708-smartrg-sr400ac.dts arch/arm/boot/dts/bcm4708-luxul-xap-1510.dts arch/arm/boot/dts/bcm953012er.dts arch/arm/boot/dts/bcm4708-netgear-r6250.dts arch/arm/boot/dts/bcm4708-buffalo-wzr-1166dhp-common.dtsi arch/arm/boot/dts/bcm4708-luxul-xwc-1000.dts arch/arm/boot/dts/bcm47094-luxul-abr-4500.dts - lacks phy-mode and fixed-link arch/arm/boot/dts/bcm53016-meraki-mr32.dts - lacks phy-mode Verdict: opt all switches out of strict validation. Because there is a pattern where newly added switches reuse existing drivers more often than introducing new ones, I've opted for deciding who gets to skip validation based on an OF compatible match table in the DSA core. The alternative would have been to add another boolean property to struct dsa_switch, like configure_vlan_while_not_filtering. But this avoids situations where sometimes driver maintainers obfuscate what goes on by sharing a common probing function, and therefore making new switches inherit old quirks. This change puts an upper bound to the number of switches for which a link management description must be faked, and also makes it clearer which switches need to be tested using that logic and which don't. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
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