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| -rw-r--r-- | src/vendorcode/google/chromeos/acpi/vpd.asl | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/src/vendorcode/google/chromeos/acpi/vpd.asl b/src/vendorcode/google/chromeos/acpi/vpd.asl new file mode 100644 index 0000000000..3b262f75a8 --- /dev/null +++ b/src/vendorcode/google/chromeos/acpi/vpd.asl @@ -0,0 +1,226 @@ +/* + * 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. + */ + +/* + * This device provides an ACPI interface to read VPD keys from either + * the RO_VPD or RW_VPD region. For example: + * + * VPD.VPDF ("RO", "ro_key_name") + * VPD.VPDF ("RW", "rw_key_name") + */ + +Device (VPD) +{ + Name (_HID, "GOOG000F") + Name (_UID, 1) + Name (_STA, 0xf) + + Name (VOFS, 0x600) /* Start of VPD header in VPD region */ + Name (VIHL, 0x10) /* Length of VPD info header */ + Name (VPET, 0x00) /* VPD Entry Type: Terminator */ + Name (VPES, 0x01) /* VPD Entry Type: String */ + Name (VPEI, 0xfe) /* VPD Entry Type: Info (header) */ + Name (MORE, 0x80) /* Bit to indicate more length bytes */ + + Name (VPTR, Zero) /* Pointer to current byte in VPD for parser */ + Name (VEND, Zero) /* End of VPD region */ + + /* + * VLOC() - Return location and length of VPD region in memory. + * These values must be initialized in GNVS by coreboot. + * + * Returns: Package indicating start and length of region: + * [0] = Address of the start of VPD region. + * [1] = Length of the VPD region. + */ + Method (VLOC, 1, Serialized) + { + Switch (ToString (Arg0)) + { + Case ("RO") { + Return (Package () { \ROVP, \ROVL }) + } + Case ("RW") { + Return (Package () { \RWVP, \RWVL }) + } + Default { + Return (Package () { Zero, Zero }) + } + } + } + + /* + * VVPD() - Verify VPD info header. + * Arg0: VPD partition base address. + * Returns: VPD length or Zero if VPD header is not valid. + */ + Method (VVPD, 1, Serialized) + { + Local0 = Arg0 + ^VOFS + + OperationRegion (VPDH, SystemMemory, Local0, ^VIHL) + Field (VPDH, DWordAcc, NoLock, Preserve) + { + TYPE, 8, /* VPD Header Tag (=0xfe) */ + KLEN, 8, /* Key length (=9) */ + IVER, 8, /* Info version (=1) */ + SIGN, 64, /* Signature (="gVpdInfo") */ + VLEN, 8, /* Value length (=4) */ + SIZE, 32, /* VPD length */ + } + + If (TYPE != ^VPEI) { + Return (Zero) + } + If (KLEN != 9) { + Return (Zero) + } + If (IVER != 1) { + Return (Zero) + } + If (ToString (SIGN) != "gVpdInfo") { + Return (Zero) + } + If (VLEN != 4) { + Return (Zero) + } + + Return (SIZE) + } + + /* Return next byte from VPD at pointer VPTR, and increment VPTR. */ + Method (VPRB, 0, Serialized) + { + If (^VPTR > ^VEND) { + Printf ("Access beyond end of VPD region") + Return (Zero) + } + + Local0 = ^VPTR + OperationRegion (VPDR, SystemMemory, Local0, One) + Field (VPDR, DWordAcc, NoLock, Preserve) + { + BYTE, 8, + } + + /* Increment address pointer */ + ^VPTR++ + Return (BYTE) + } + + /* Extract and return next string from VPD. */ + Method (VPDE, 0, Serialized) + { + Local0 = One /* Indicates if there are more bytes */ + Local1 = Zero /* Length */ + + /* Decode the string length */ + While (Local0) { + /* Read the next byte at indicated address */ + Local2 = ^VPRB () + + /* Update the more bit from the byte in Local2 */ + Local0 = Local2 >> 7 + + /* Save the length bits from Local2 */ + Local1 <<= 7 + Local1 |= Local2 & 0x7f + } + If (!Local1) { + Return (Zero) + } + + /* Extract the string */ + Local3 = Zero + Local4 = "" + While (Local3 < Local1) { + Concatenate (Local4, ToString (^VPRB ()), Local4) + Local3++ + } + + Return (Local4) + } + + /* + * VPDS() - Find next VPD key and value. + * Returns: Package containing key and value: + * [0] = VPD key string + * [1] = VPD value string + */ + Method (VPDS, 0, Serialized) + { + Name (VPKV, Package () { Zero, Zero }) + + /* Read the VPD type and ensure it is a string */ + If (^VPRB () != ^VPES) { + Printf ("VPDS: Type is not a string") + Return (VPKV) + } + + /* Extract the key string and value */ + VPKV[0] = VPDE () + VPKV[1] = VPDE () + + Return (VPKV) + } + + /* + * VPDF() - Find VPD key with matching name. + * Arg0: VPD Partition, either "RO" or "RW". + * Arg1: VPD key name to search for. + * Returns: VPD string corresponding to VPD key, or Zero if not found. + */ + Method (VPDF, 2, Serialized) + { + Local0 = VLOC (Arg0) + + /* Start of VPD region */ + ^VPTR = DerefOf (Local0[0]) + + /* End address of VPD region */ + ^VEND = ^VPTR + DerefOf (Local0[1]) + + If (!^VPTR || !^VEND) { + Printf ("Unable to find VPD region") + Return (Zero) + } + + /* Verify VPD info header and save size */ + Local0 = VVPD (^VPTR) + If (!Local0) { + Printf ("VPD region %o did not verify", Arg0) + Return (Zero) + } + + /* Set VPD pointer to start of VPD entries */ + ^VPTR += ^VOFS + ^VIHL + + /* Search through VPD entries until key is found */ + Local1 = "" + While (Local1 != ToString (Arg1)) { + Local2 = VPDS () + Local1 = DerefOf (Local2[0]) + If (!Local1) { + Printf ("VPD KEY %o not found", Arg1) + Return (Zero) + } + } + Local3 = DerefOf (Local2[1]) + + Printf ("Found VPD KEY %o = %o", Local1, Local3) + Return (Local3) + } +} |