From 57d5e47694c851ec5dc78860d725f9e63c1e6dfc Mon Sep 17 00:00:00 2001 From: Duncan Laurie Date: Fri, 1 Mar 2019 15:40:48 +0800 Subject: vendorcode/google/chromeos: Support MAC address passthru policy This change adds support for providing a MAC address that can be used by the OS network drivers to change the MAC address that a NIC uses. The Realtek r8152 driver in the Linux kernel supports a MAC address passthru feature which can result in the dock ethernet port using the same MAC address that is assigned to the internal NIC. This is done by calling an ACPI method at \_SB.AMAC() which returns a formatted string containing the MAC address for the dock to use. The Linux kernel implementation can be found at drivers/net/usb/r8152.c:vendor_mac_passthru_addr_read() This is implemented specifically for Chrome OS as it relies on VPD to determine the MAC address to supply. The policy which controls where the dock MAC address comes from is written into RW_VPD property "dock_passthru": "dock_mac" or empty: Use MAC address from RO_VPD value "dock_mac" "ethernet_mac0": Use MAC address from RO_VPD value "ethernet_mac0" "builtin": existing dock MAC address (return nothing) The MAC address in VPD is the standard format AA:BB:CC:DD:EE:FF and it must be converted into the string format expected by the OS which involves some string manipulation which ACPI is not great at handling. BUG=b:123925776 TEST=this was tested on a sarien board by setting the VPD keys to their expected values and observing if the AMAC() method returns the expected string. Change-Id: I3335e5d924155431e299844e2aaace62168294e0 Signed-off-by: Duncan Laurie Reviewed-on: https://review.coreboot.org/c/31669 Tested-by: build bot (Jenkins) Reviewed-by: Lijian Zhao --- src/vendorcode/google/chromeos/acpi/amac.asl | 85 ++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 src/vendorcode/google/chromeos/acpi/amac.asl (limited to 'src/vendorcode/google/chromeos') diff --git a/src/vendorcode/google/chromeos/acpi/amac.asl b/src/vendorcode/google/chromeos/acpi/amac.asl new file mode 100644 index 0000000000..838506abcb --- /dev/null +++ b/src/vendorcode/google/chromeos/acpi/amac.asl @@ -0,0 +1,85 @@ +/* + * This file is part of the coreboot project. + * + * Copyright 2019 Google LLC + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; version 2 of + * the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +/* + * The Realtek r8152 driver in the Linux kernel supports a MAC address + * passthru feature which can result in the dock ethernet port using the + * same MAC address that is assigned to the internal NIC. This is done + * by calling an ACPI method at \_SB.AMAC() which returns a formatted + * string containing the MAC address for the dock to use. + * + * The Linux kernel implementation can be found at + * drivers/net/usb/r8152.c:vendor_mac_passthru_addr_read() + * + * For Chrome OS, the policy which controls where the dock MAC address + * comes from is written into RW_VPD property "dock_passthru": + * + * "dock_mac" or empty: Use MAC address from RO_VPD value "dock_mac" + * "ethernet_mac0": Use MAC address from RO_VPD value "ethernet_mac0" + * "builtin": existing dock MAC address (return nothing) + */ + +Scope (\_SB) +{ + Method (AMAC, 0, Serialized) + { + /* Format expected by the Linux kernel r8152 driver */ + Name (MACA, "_AUXMAC_#XXXXXXXXXXXX#") + + /* Get "dock_passthru" value from RW_VPD */ + Local0 = \VPD.VPDF ("RW", "dock_passthru") + + Switch (ToString (Local0)) + { + Case ("ethernet_mac0") { + Local1 = \VPD.VPDF ("RO", "ethernet_mac0") + } + Case ("builtin") { + Return (Zero) + } + /* "dock_mac" or policy not found. */ + Default { + Local1 = \VPD.VPDF ("RO", "dock_mac") + } + } + If (!Local1) { + Return (Zero) + } + Printf ("MAC address returned from VPD: %o", Local1) + + /* Verify MAC address format is AA:BB:CC:DD:EE:FF */ + For (Local3 = 2, Local3 < 17, Local3 += 3) { + If (ToString (DerefOf (Local1[Local3])) != ":") { + Printf ("Invalid MAC address byte %o", Local3) + Return (Zero) + } + } + + /* Convert MAC address into format specified by MACA */ + Local2 = ToBuffer (MACA) + Local4 = 0 /* First MAC address byte in input buffer */ + Local5 = 9 /* First MAC address byte in output buffer */ + For (Local3 = 0, Local3 < 6, Local3++) { + Local2[Local5] = DerefOf (Local1[Local4]) + Local2[Local5 + 1] = DerefOf (Local1[Local4 + 1]) + Local5 += 2 + Local4 += 3 /* Skip ":" in address from VPD */ + } + + Printf ("AMAC = %o", ToString (Local2)) + Return (ToString (Local2)) + } +} -- cgit v1.2.3