Based on kernel version 6.8
. Page generated on 2024-03-11 21:26 EST
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 | .. SPDX-License-Identifier: GPL-2.0 ========================= MDIO bus and PHYs in ACPI ========================= The PHYs on an MDIO bus [phy] are probed and registered using fwnode_mdiobus_register_phy(). Later, for connecting these PHYs to their respective MACs, the PHYs registered on the MDIO bus have to be referenced. This document introduces two _DSD properties that are to be used for connecting PHYs on the MDIO bus [dsd-properties-rules] to the MAC layer. These properties are defined in accordance with the "Device Properties UUID For _DSD" [dsd-guide] document and the daffd814-6eba-4d8c-8a91-bc9bbf4aa301 UUID must be used in the Device Data Descriptors containing them. phy-handle ---------- For each MAC node, a device property "phy-handle" is used to reference the PHY that is registered on an MDIO bus. This is mandatory for network interfaces that have PHYs connected to MAC via MDIO bus. During the MDIO bus driver initialization, PHYs on this bus are probed using the _ADR object as shown below and are registered on the MDIO bus. .. code-block:: none Scope(\_SB.MDI0) { Device(PHY1) { Name (_ADR, 0x1) } // end of PHY1 Device(PHY2) { Name (_ADR, 0x2) } // end of PHY2 } Later, during the MAC driver initialization, the registered PHY devices have to be retrieved from the MDIO bus. For this, the MAC driver needs references to the previously registered PHYs which are provided as device object references (e.g. \_SB.MDI0.PHY1). phy-mode -------- The "phy-mode" _DSD property is used to describe the connection to the PHY. The valid values for "phy-mode" are defined in [ethernet-controller]. managed ------- Optional property, which specifies the PHY management type. The valid values for "managed" are defined in [ethernet-controller]. fixed-link ---------- The "fixed-link" is described by a data-only subnode of the MAC port, which is linked in the _DSD package via hierarchical data extension (UUID dbb8e3e6-5886-4ba6-8795-1319f52a966b in accordance with [dsd-guide] "_DSD Implementation Guide" document). The subnode should comprise a required property ("speed") and possibly the optional ones - complete list of parameters and their values are specified in [ethernet-controller]. The following ASL example illustrates the usage of these properties. DSDT entry for MDIO node ------------------------ The MDIO bus has an SoC component (MDIO controller) and a platform component (PHYs on the MDIO bus). a) Silicon Component This node describes the MDIO controller, MDI0 --------------------------------------------- .. code-block:: none Scope(_SB) { Device(MDI0) { Name(_HID, "NXP0006") Name(_CCA, 1) Name(_UID, 0) Name(_CRS, ResourceTemplate() { Memory32Fixed(ReadWrite, MDI0_BASE, MDI_LEN) Interrupt(ResourceConsumer, Level, ActiveHigh, Shared) { MDI0_IT } }) // end of _CRS for MDI0 } // end of MDI0 } b) Platform Component The PHY1 and PHY2 nodes represent the PHYs connected to MDIO bus MDI0 --------------------------------------------------------------------- .. code-block:: none Scope(\_SB.MDI0) { Device(PHY1) { Name (_ADR, 0x1) } // end of PHY1 Device(PHY2) { Name (_ADR, 0x2) } // end of PHY2 } DSDT entries representing MAC nodes ----------------------------------- Below are the MAC nodes where PHY nodes are referenced. phy-mode and phy-handle are used as explained earlier. ------------------------------------------------------ .. code-block:: none Scope(\_SB.MCE0.PR17) { Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package (2) {"phy-mode", "rgmii-id"}, Package (2) {"phy-handle", \_SB.MDI0.PHY1} } }) } Scope(\_SB.MCE0.PR18) { Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package (2) {"phy-mode", "rgmii-id"}, Package (2) {"phy-handle", \_SB.MDI0.PHY2}} } }) } MAC node example where "managed" property is specified. ------------------------------------------------------- .. code-block:: none Scope(\_SB.PP21.ETH0) { Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package () {"phy-mode", "sgmii"}, Package () {"managed", "in-band-status"} } }) } MAC node example with a "fixed-link" subnode. --------------------------------------------- .. code-block:: none Scope(\_SB.PP21.ETH1) { Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package () {"phy-mode", "sgmii"}, }, ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"), Package () { Package () {"fixed-link", "LNK0"} } }) Name (LNK0, Package(){ // Data-only subnode of port ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package () {"speed", 1000}, Package () {"full-duplex", 1} } }) } References ========== [phy] Documentation/networking/phy.rst [dsd-properties-rules] Documentation/firmware-guide/acpi/DSD-properties-rules.rst [ethernet-controller] Documentation/devicetree/bindings/net/ethernet-controller.yaml [dsd-guide] DSD Guide. https://github.com/UEFI/DSD-Guide/blob/main/dsd-guide.adoc, referenced 2021-11-30. |