ACPI - 高级配置和电源管理接口（Advanced Configuration and Power Management Interface）

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ACPI其实是一种电源管理标准,ACPI是Advanced Configuration and Power Interface的首字母缩写,一般翻译成高级电源管理,是Intel、Microsoft和东芝共同开发的一种电源管理标准。

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基本概念

1. ACPI是一种定义BIOS和OS之间接口的方法。和DTS等不同，ACPI支持函数接口，也就是说OS可以通过“调用”BIOS ACPI表中的函数接口来实现功能；所谓的调用有几种可能：
   a. BIOS中给定一个数据结构，整体描述了一个函数，该函数本身就是CPU的本地汇编。BIOS把整个数据接口传递到OS管理的内存空间，OS直接调用这个空间中的函数。
   b. BIOS中给定一个数据结构，整体描述了一个函数，该函数本身就是CPU的本地汇编。这个数据结构留在BIOS控制的内存中，传递给OS一个指针，OS远程调用这个指令的地址，完成请求。
   c. BIOS中实现了一个本地函数，然后把这个函数的位置和格式告知OS，OS通过一个统一的接口把函数的标识和请求的参数传递给BIOS，BIOS内部完成调用，然后把结果通知OS。
   d. BIOS给定一个数据结构，整体描述了一个函数，用一种平台无关的格式标识，这个数据结构整体提供给OS，OS上有一个解释器，解释执行这个平台无关的格式，实现对功能的执行。
2. ACPI表DSDT.dsl文件中实现相关描述与Method，是一种解释型的语言，而不是被编成了二进制；
3. OS中存在一个解释器，AML是一个类似java的Bincode，通过解释器建立数据结构，从而可以解释执行；
4. Linux内核的具体实现：ACPI Method Execute-flow：acpi_evaluate_integer-->acpi_evaluate_object-->acpi_ns_evaluate-->acpi_ps_execute_method-->acpi_ps_parse_aml；
5. /sys/firmware/acpi/tables：DSDT：单板目录；
6. zypper install iasl：安装解析工具；
7. iasl -d DSDT：解析ACPI文件；
8. vim DSDT.dsl：相当于dts文件；

[vieyahn2017]

参考资料

1. Linux设备驱动--pci总线的初始化：https://blog.csdn.net/whenloce/article/details/90901438
2. 解析acpi表：
3. AML工作原理快速调研：https://zhuanlan.zhihu.com/p/113296734
4. ACPI Summary：https://maggie262.github.io/2020/02/06/acpi-summary/
5. ASL tutorial：https://acpica.org/sites/acpica/files/asl_tutorial_v20190625.pdf
6. ACPI Introduction：https://acpica.org/sites/acpica/files/ACPI-Introduction.pdf
7. 路电 x86 2146新单板启动劣化：http://rnd-isourceb.huawei.com/Euler/rtos_r3/issues/17783

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解析acpi表

下载开源acpi工具
git clone https://github.com/acpica/acpica.git
编译

ll bin
total 2772
-rwxr-xr-x 1 55416 Apr 26 20:17 acpibin
-rwxr-xr-x 1 65456 Apr 26 20:17 acpidump
-rwxr-xr-x 1 257504 Apr 26 20:17 acpiexamples
-rwxr-xr-x 1 675424 Apr 26 20:18 acpiexec
-rwxr-xr-x 1 144856 Apr 26 20:18 acpihelp
-rwxr-xr-x 1 280968 Apr 26 20:18 acpinames
-rwxr-xr-x 1 97184 Apr 26 20:18 acpisrc
-rwxr-xr-x 1 45640 Apr 26 20:18 acpi

acpidump -o ACPI_table.out 【 输出到文件 】
acpixtract -a ACPI_table.out 【从文件解析】
ll /sys/firmware/acpi/tables/
iasl -d dsdt.dat 【 生成 dsdt.dsl 】

acpidump – dump a system’s ACPI tables to an ASCII file
acpixtract – convert ASCII acpidump output to raw binary table
turbostat – gather performance statistics

IASL：ACPI Source Language compiler/decompiler

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或者 yum install acpica-tools

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iasl

Intel ACPI Component Architecture
ASL+ Optimizing Compiler/Disassembler version 20200528
Copyright (c) 2000 - 2020 Intel Corporation

Supports ACPI Specification Revision 6.3

Usage: iasl [Options] [Files]
Options:

General:
-@ Specify command file
-I

Specify additional include directory
-p Specify path/filename prefix for all output files
-v Display compiler version
-vd Display compiler build date and time
-vo Enable optimization comments
-vs Disable signon

Help:
-h This message
-hc Display operators allowed in constant expressions
-hd Info for obtaining and disassembling binary ACPI tables
-hf Display help for output filename generation
-hr Display ACPI reserved method names
-ht Display currently supported ACPI table names

Preprocessor:
-D Define symbol for preprocessor use
-li Create preprocessed output file (.i)
-P Preprocess only and create preprocessor output file (.i)
-Pn Disable preprocessor

Errors, Warnings, and Remarks:
-va Disable all errors/warnings/remarks
-ve Report only errors (ignore warnings and remarks)
-vi Less verbose errors and warnings for use with IDEs
-vr Disable remarks
-vw Ignore specific error, warning or remark
-vx Expect a specific warning, remark, or error
-w <1|2|3> Set warning reporting level
-we Report warnings as errors
-ww Report specific warning or remark as error

AML Bytecode Generation (*.aml):
-oa Disable all optimizations (compatibility mode)
-of Disable constant folding
-oi Disable integer optimization to Zero/One/Ones
-on Disable named reference string optimization
-ot Disable typechecking
-cr Disable Resource Descriptor error checking
-in Ignore NoOp operators
-r Override table header Revision (1-255)

Listings:
-l Create mixed listing file (ASL source and AML) (.lst)
-lm Create hardware summary map file (.map)
-ln Create namespace file (.nsp)
-ls Create combined source file (expanded includes) (.src)
-lx Create cross-reference file (*.xrf)

Firmware Support - C Text Output:
-tc Create hex AML table in C (.hex)
-sc Create named hex AML arrays in C (.c)
-ic Create include file in C for -sc symbols (.h)
-so Create namespace AML offset table in C (.offset.h)

Firmware Support - Assembler Text Output:
-ta Create hex AML table in assembler (.hex)
-sa Create named hex AML arrays in assembler (.asm)
-ia Create include file in assembler for -sa symbols (*.inc)

Firmware Support - ASL Text Output:
-ts Create hex AML table in ASL (Buffer object) (*.hex)

Legacy-ASL to ASL+ Converter:
-ca Convert legacy-ASL source file to new ASL+ file
(Original comments are passed through to ASL+ file)

Data Table Compiler:
-tp Compile tables with flex/bison prototype
-G Compile custom table that contains generic operators
-T |ALL Create ACPI table template/example files
-T Emit DSDT and SSDTs to same file
-vt Create verbose template files (full disassembly)

AML Disassembler:
-d <f1 f2 ...> Disassemble or decode binary ACPI tables to file (*.dsl)
(Optional, file type is automatically detected)
-da <f1 f2 ...> Disassemble multiple tables from single namespace
-db Do not translate Buffers to Resource Templates
-dc <f1 f2 ...> Disassemble AML and immediately compile it
(Obtain DSDT from current system if no input file)
-df Force disassembler to assume table contains valid AML
-dl Emit legacy ASL code only (no C-style operators)
-e <f1 f2 ...> Include ACPI table(s) for external symbol resolution
-fe Specify external symbol declaration file
-in Ignore NoOp opcodes
-l Disassemble to mixed ASL and AML code
-vt Dump binary table data in hex format within output file

Debug Options:
-bc Create converter debug file (.cdb)
-bf Create debug file (full output) (.txt)
-bs Create debug file (parse tree only) (*.txt)
-bp Prune ASL parse tree
-bt Object type to be pruned from the parse tree
-f Ignore errors, force creation of AML output file(s)
-m Set internal line buffer size (in Kbytes)
-n Parse only, no output generation
-oc Display compile times and statistics
-x Set debug level for trace output
-z Do not insert new compiler ID for DataTables

[vieyahn2017]

ll /sys/firmware/acpi/tables
total 0
-r-------- 1 root root 772 Aug 1 17:08 APIC
-r-------- 1 root root 165 Aug 1 17:08 'ASF!'
-r-------- 1 root root 48 Aug 1 17:08 BDAT
-r-------- 1 root root 48 Aug 1 17:08 BERT
-r-------- 1 root root 40 Aug 1 17:08 BOOT
drwxr-xr-x 2 root root 0 Aug 1 17:08 data
-r-------- 1 root root 52 Aug 1 17:08 DBGP
-r-------- 1 root root 280 Aug 1 17:08 DMAR
-r-------- 1 root root 186073 Aug 1 17:08 DSDT
drwxr-xr-x 2 root root 0 Aug 1 17:08 dynamic
-r-------- 1 root root 336 Aug 1 17:08 EINJ
-r-------- 1 root root 560 Aug 1 17:08 ERST
-r-------- 1 root root 268 Aug 1 17:08 FACP
-r-------- 1 root root 64 Aug 1 17:08 FACS
-r-------- 1 root root 68 Aug 1 17:08 FPDT
-r-------- 1 root root 168 Aug 1 17:08 HEST
-r-------- 1 root root 56 Aug 1 17:08 HPET
-r-------- 1 root root 60 Aug 1 17:08 MCFG
-r-------- 1 root root 209 Aug 1 17:08 PRAD
-r-------- 1 root root 108 Aug 1 17:08 SLIT
-r-------- 1 root root 65 Aug 1 17:08 SPMI
-r-------- 1 root root 976 Aug 1 17:08 SRAT
-r-------- 1 root root 1480 Aug 1 17:08 SSDT1
-r-------- 1 root root 1608 Aug 1 17:08 SSDT2
-r-------- 1 root root 566 Aug 1 17:08 UEFI1
-r-------- 1 root root 66 Aug 1 17:08 UEFI2
-r-------- 1 root root 404 Aug 1 17:08 WDAT

[vieyahn2017]

ACPI定义了很多的表，这里不一一说明，下面是其中的一些：

• Root System Description Table (RSDT)
• Fixed ACPI Description Table (FADT)
• Firmware ACPI Control Structure (FACS)
• Differentiated System Description Table (DSDT) 差异化系统描述表
• Secondary System Description Table (SSDT)
• Multiple APIC Description Table (MADT)
• Smart Battery Table (SBST)
• Extended System Description Table (XSDT)
• Embedded Controller Boot Resources Table (ECDT)
• System Locality Distance Information Table (SLIT)
• System Resource Affinity Table (SRAT)
• Corrected Platform Error Polling Table (CPEP)
• Maximum System Characteristics Table (MSCT)
• ACPI RAS Feature Table (RASF)
• Memory Power State Table (MPST)
• Platform Memory Topology Table (PMTT)
• Boot Graphics Resource Table (BGRT)
• Firmware Performance Data Table (FPDT) 固件性能数据表
• Generic Timer Description Table (GTDT)
• NVDIMM Firmware Interface Table (NFIT)

ACPI Spec的第五章ACPI Software Programming Model中对它们有介绍。

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参考
https://github.com/edk2-porting/edk2-msm/blob/7352c1a46b208ab90184cbc7e97b63d3088dc574/Platform/Xiaomi/sm6225/AcpiTables/fog/DSDT.dsl#L4

DefinitionBlock ("", "DSDT", 2, "QCOMM ", "SM6225 ", 0x00000003)

[vieyahn2017]

Linux内核深入理解定时器和时间管理（6）：x86_64 相关的时钟源（kvm-clock，tsc，acpi_pm，hpet）

https://blog.csdn.net/Rong_Toa/article/details/115350561

[vieyahn2017]

在BIOS向OS报告的ACPI表中，最重要的是SRAT（System Resource Affinity Table 系统资源亲和性表）和SLIT（System Locality Information Table 系统位置信息表）。

SRAT中包含两个结构

Processor Local APIC/SAPIC Affinity Structure：每个逻辑Processor在Proximity Domain所处的位置。每个逻辑Processor都有不同的Local APIC ID，所以Processor用Local APIC ID表示。
Memory Affinity Structure：记录内存的信息，即每块内存都从属于哪个Proximity Domain。
有了这个表OSPM就可以描绘出一个CPU和内存的关系图，包括有几个node，每个node里面有那些逻辑Processor和内存。

SLIT表则记录了各个结点之间的距离

通过这两个表，OS可以在内存中建立整体Processor和内存的亲缘关系图和距离表，作为任务调度和内存分配的依据。详细信息可以查看ACPI Spec 6.1的第17章节

=== 【这两跟NUMA相关】