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| -rw-r--r-- | src/vendorcode/google/chromeos/acpi/amac.asl | 85 |
1 files changed, 85 insertions, 0 deletions
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)) + } +} |