| Duncan Laurie | 57d5e47 | 2019-03-01 15:40:48 +0800 | [diff] [blame^] | 1 | /* |
| 2 | * This file is part of the coreboot project. |
| 3 | * |
| 4 | * Copyright 2019 Google LLC |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU General Public License as |
| 8 | * published by the Free Software Foundation; version 2 of |
| 9 | * the License. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | */ |
| 16 | |
| 17 | /* |
| 18 | * The Realtek r8152 driver in the Linux kernel supports a MAC address |
| 19 | * passthru feature which can result in the dock ethernet port using the |
| 20 | * same MAC address that is assigned to the internal NIC. This is done |
| 21 | * by calling an ACPI method at \_SB.AMAC() which returns a formatted |
| 22 | * string containing the MAC address for the dock to use. |
| 23 | * |
| 24 | * The Linux kernel implementation can be found at |
| 25 | * drivers/net/usb/r8152.c:vendor_mac_passthru_addr_read() |
| 26 | * |
| 27 | * For Chrome OS, the policy which controls where the dock MAC address |
| 28 | * comes from is written into RW_VPD property "dock_passthru": |
| 29 | * |
| 30 | * "dock_mac" or empty: Use MAC address from RO_VPD value "dock_mac" |
| 31 | * "ethernet_mac0": Use MAC address from RO_VPD value "ethernet_mac0" |
| 32 | * "builtin": existing dock MAC address (return nothing) |
| 33 | */ |
| 34 | |
| 35 | Scope (\_SB) |
| 36 | { |
| 37 | Method (AMAC, 0, Serialized) |
| 38 | { |
| 39 | /* Format expected by the Linux kernel r8152 driver */ |
| 40 | Name (MACA, "_AUXMAC_#XXXXXXXXXXXX#") |
| 41 | |
| 42 | /* Get "dock_passthru" value from RW_VPD */ |
| 43 | Local0 = \VPD.VPDF ("RW", "dock_passthru") |
| 44 | |
| 45 | Switch (ToString (Local0)) |
| 46 | { |
| 47 | Case ("ethernet_mac0") { |
| 48 | Local1 = \VPD.VPDF ("RO", "ethernet_mac0") |
| 49 | } |
| 50 | Case ("builtin") { |
| 51 | Return (Zero) |
| 52 | } |
| 53 | /* "dock_mac" or policy not found. */ |
| 54 | Default { |
| 55 | Local1 = \VPD.VPDF ("RO", "dock_mac") |
| 56 | } |
| 57 | } |
| 58 | If (!Local1) { |
| 59 | Return (Zero) |
| 60 | } |
| 61 | Printf ("MAC address returned from VPD: %o", Local1) |
| 62 | |
| 63 | /* Verify MAC address format is AA:BB:CC:DD:EE:FF */ |
| 64 | For (Local3 = 2, Local3 < 17, Local3 += 3) { |
| 65 | If (ToString (DerefOf (Local1[Local3])) != ":") { |
| 66 | Printf ("Invalid MAC address byte %o", Local3) |
| 67 | Return (Zero) |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | /* Convert MAC address into format specified by MACA */ |
| 72 | Local2 = ToBuffer (MACA) |
| 73 | Local4 = 0 /* First MAC address byte in input buffer */ |
| 74 | Local5 = 9 /* First MAC address byte in output buffer */ |
| 75 | For (Local3 = 0, Local3 < 6, Local3++) { |
| 76 | Local2[Local5] = DerefOf (Local1[Local4]) |
| 77 | Local2[Local5 + 1] = DerefOf (Local1[Local4 + 1]) |
| 78 | Local5 += 2 |
| 79 | Local4 += 3 /* Skip ":" in address from VPD */ |
| 80 | } |
| 81 | |
| 82 | Printf ("AMAC = %o", ToString (Local2)) |
| 83 | Return (ToString (Local2)) |
| 84 | } |
| 85 | } |