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| /** @file
| SSDT for the ACPI Debug feature.
|
| Copyright (c) 2019, Intel Corporation. All rights reserved.<BR>
| SPDX-License-Identifier: BSD-2-Clause-Patent
|
| **/
|
| DefinitionBlock (
| "AcpiDebug.aml",
| "SSDT",
| 2,
| "Intel ",
| "ADebTabl",
| 0x1000
| )
| {
| Scope(\)
| {
| //
| // These pointers are patched during POST.
| //
| Name (DPTR, 0x80000000) // Address of Acpi debug memory buffer, fixed up during POST
| Name (EPTR, 0x80000000) // End of Acpi debug memory buffer, fixed up during POST
| Name (CPTR, 0x80000000) // Current pointer used as an index into the buffer(starts after the Acpi Debug head), fixed up during POST
|
| //
| // Use a Mutex to prevent multiple calls from simutaneously writing to the same memory.
| //
| Mutex (MMUT, 0)
|
| //
| // Operational region for SMI port access
| //
| OperationRegion (ADBP, SystemIO, 0xB2, 2)
| Field (ADBP, ByteAcc, NoLock, Preserve)
| {
| B2PT, 8,
| B3PT, 8,
| }
|
| //
| // Write a string to a memory buffer
| //
| Method (MDBG, 1, Serialized)
| {
| OperationRegion (ADHD, SystemMemory, DPTR, 32) // Operation region for Acpi Debug buffer first 0x20 bytes
| Field (ADHD, ByteAcc, NoLock, Preserve)
| {
| Offset (0x0),
| ASIG, 128, // 16 bytes is Signature
| Offset (0x10),
| ASIZ, 32, // 4 bytes is buffer size
| ACHP, 32, // 4 bytes is current head pointer, normally is DPTR + 0x20,
| // if there's SMM handler to print, then it's the starting of the info hasn't been printed yet.
| ACTP, 32, // 4 bytes is current tail pointer, is the same as CPTR
| SMIN, 8, // 1 byte of SMI Number for trigger callback
| WRAP, 8, // 1 byte of wrap status
| SMMV, 8, // 1 byte of SMM version status
| TRUN, 8 // 1 byte of truncate status
| }
|
| Store (Acquire (MMUT, 1000), Local0) // save Acquire result so we can check for Mutex acquired
| If (LEqual (Local0, Zero)) // check for Mutex acquired
| {
| OperationRegion (ABLK, SystemMemory, CPTR, 32) // Operation region to allow writes to ACPI debug buffer
| Field (ABLK, ByteAcc, NoLock, Preserve)
| {
| Offset (0x0),
| AAAA, 256 // 32 bytes is max size for string or data
| }
| ToHexString (Arg0, Local1) // convert argument to Hexadecimal String
| Store (0, TRUN)
| If (LGreaterEqual (SizeOf (Local1), 32))
| {
| Store (1, TRUN) // the input from ASL >= 32
| }
| Mid (Local1, 0, 31, AAAA) // extract the input to current buffer
|
| Add (CPTR, 32, CPTR) // advance current pointer to next string location in memory buffer
| If (LGreaterEqual (CPTR, EPTR) ) // check for end of 64kb Acpi debug buffer
| {
| Add (DPTR, 32, CPTR) // wrap around to beginning of buffer if the end has been reached
| Store (1, WRAP)
| }
| Store (CPTR, ACTP)
|
| If (SMMV)
| {
| //
| // Trigger the SMI to print
| //
| Store (SMIN, B2PT)
| }
| Release (MMUT)
| }
|
| Return (Local0) // return error code indicating whether Mutex was acquired
| }
|
| } // End Scope
| } // End SSDT
|
|
