1. MSI
MSI
Micro-Star International

2. Advanced Configuration and Power Interface
ACPI
Advanced Configuration and Power Interface
Reporter :Wequalwu

3. Contents ACPI Overview ASL (ACPI Source Language)
ACPI Implementer in AWARD BIOS

4. History of Power Management
SL technology
First seen on the 386SL and still included in all of today’s Pentium and Pentium II processors
Operating system had no idea of what the power management BIOS was up to.
Advanced Power Management
Intel & Microsoft co-developed
OS and power management BIOS could now talk to each other
No cooperation among system components
Add-on components do not participate in power management
ACPI (Advanced Configuration and Power Interface)
Intel, Toshiba and Microsoft
Open industry, all encompassing, PC hardware, operating system and peripheral device interface specifications
Primary goal is to let O.S. manage all power activity

5. ACPI Introduction 1. industry common interfaces
2. The key element in Operating System-directed
configuration and Power Management (OSPM).
3. stretch the limits of current Plug and Play interfaces.
4. more robust, and potentially more efficient manner.
5. collection of power management BIOS code, Advanced Power Management (APM) application programming interfaces (APIs, PNPBIOS APIs, Multiprocessor Specification (MPS)
6. suitable to all classes of computers including (but not limited to) desktop, mobile, workstation, and server machines

6. Principal Goals
1. ACPI provides OSPM with direct and exclusive control over the power management and motherboard device configuration functions of a computer. OS plays a central role and uses global information to optimize system behavior. ACPI is the key element in OSPM
2. Enable all computer systems to implement motherboard configuration and power management functions
3. Enhance power management functionality and robustness.
4. Facilitate and accelerate industry-wide implementation of power management.
5. Create a robust interface for configuring motherboard devices.

7. ACPI Function System power management Device power management
Processor power management
Plug and Play
System Events
Battery management
Thermal management
Embedded Controller
SMBus Controller

8. Seven Operation Region Types
0 – SystemMemory
1 – SystemIO
2 – PCI_Config
3 – EmbeddedControl
4 – SMBus
5 – CMOS
6 – PCIBARTarget

9. OSPM/ACPI Global System

10. ACPI run-time components
ACPI Tables
Describe the interfaces to the hardware.
ACPI Registers
The constrained part of the hardware interface, described (at least in location) by the ACPI System Description Tables.
ACPI BIOS
ACPI system firmware.The firmwares boots the machine and compatible with ACPI spec.

11. ACPI Power States Global System States
G Working (System Operational)
G Sleeping - no user threads, system looks off
G2/S5 --Soft Off
G Mechanical off (Physical off switch)
Device Power States
D3 - Off - Power off to device
D2 - Less power than D1 (Depends on device)
D1 - Less power than D0 (Depends on Device)
D0 - Fully-On
Processor Power States
C0 - Full power, instructions execute
C1 - Processor stopped
C2 - Processor stopped, less power than C1
C3 - Processor stopped, caches ignore snoops
Sleeping States
S0 - system Working
S1 - Low Latency Sleeping State Processor Context Maintained
S2 - Low Latency Sleeping State Processor Context Not Maintained
S3 - Low Latency Sleeping State DRAM still maintained
S4 - Lowest power longest wake-up - DRAM not maintained
S5 - Soft Off State

12. System Power States

13. OSPM Implementations
1.Use system address map reporting interfaces. (int15h,e820h)
2.Find and consume the ACPI System Description Tables.
3.Interpret ACPI machine language (AML).
4.Enumerate and configure motherboard devices described in the ACPI Namespace.
5.Interface with the power management timer.
6.Interface with the real-time clock wake alarm.
7.Enter ACPI mode (on legacy hardware systems).
8.Implement device power management policy.
9.Implement power resource management.
10.Implement processor power states in the scheduler idle handlers.
11.Control processor and device performance states.
12.Implement the ACPI thermal model.
13.Support the ACPI Event programming model including handling SCI interrupts, managing fixed events, general-purpose events, embedded controller interrupts, and dynamic device support.
14.Support acquisition and release of the Global Lock.
15.Use the reset register to reset the system.
16.Provide APIs to influence power management policy.
17.Implement driver support for ACPI-defined devices.
18.Implement APIs supporting the system indicators.
19.Support all system states S1–S5.

14. ACPI Hardware Fixed Hardware Programming Model
Performance sensitive features
Features that drivers require during wake
Features that enable catastrophic OS software failure recovery
CPU clock control
Power management timer
Fixed hardware registers
Generic Hardware Programming Model
OEM-provided AML code

15. Generic Hardware Feature Model

16. Global States and Their Transitions

17. Register model Fixed hardware registers and Generic hardware registers
System I/O
System memory
PCI configuration
SMBus
Embedded controller
Functional Fixed Hardware

20. Example: PM1

22. ACPI Software
ACPI uses tables to describe system information, features, and methods for controlling features.
RSDT--Root System Description Table.
XSDT--Extended System Description Table.
FADT--Fixed ACPI Description Table.
DSDT--Differentiated System Description Table.
FACS--Firmware ACPI Control Structure.
SSDT--Secondary System Description Table. ……

23. System Description Table Architecture
F000:xxxx
Top Memory
RSD PTR
RSDT(XSDT)
FACS
RSD PTR:Root System Description Pointer
RSDT:Root System Description Table
FADT:Fixed ACPI Description Table
FACS:Fimware ACPI Control Structure
DSDT:Differentiated System Description table
SSDT:Secondary System Description Table
FADT
DSDT
DBGP
APIC
MP(APIC)
BOOT
Simple boot flag
SSDT

25. RSD_PTR: db "RSD PTR “ ;RSD PTR Signature
W6555
Acpi.asm
;Build RSD PTR table
ALIGN 16
Public RSD_PTR
RSD_PTR: db "RSD PTR “ ;RSD PTR Signature
RSD_CKSM: db 0 ;Checksum, fill in at POST ……
RSDT_Ptr: db 4 dup (?) ;RSDT physical address, fill in at POST
RSDPTRLength EQU ($-RSD_PTR)

26. ……

27. db "RSDT" ;Signaturedb 4 dup (?) ……
W6555
Acpitbl.asm
;RSDT table
RSDTtable:
db "RSDT" ;Signaturedb 4 dup (?) ……
db 4 dup (?) ;Pointer of FACP table
ifdef SIMPLE_BOOT_SUPPORT
db 4 dup (?) ; Pointer of BOOT table
endif ;SIMPLE_BOOT_SUPPORT
ifdef Debug_port_table ;R09
db 4 dup (?) ;R09 Pointer of DBGP table
endif ;Debug_port_table ;R09

29. Fixed ACPI Description Table (FADT)
FADT defines various fixed hardware ACPI information vital to an ACPI-compatible OS, such as the base address for the following hardware registers blocks:
PM1a_EVT_BLK, PM1b_EVT_BLK, PM1a_CNT_BLK, PM1b_CNT_BLK……

30. …… …… ……

31. db 4 dup (?) ;Pointer of FACS table
W6555
Acpitbl.asm
FACPtable:
db "FACP" ;Signature ……
db 4 dup (?) ;Pointer of FACS table
db 4 dup (?) ;Pointer of DSDT table
dd PM1a_EVT_BLK
dd PM1b_EVT_BLK
dd GPE0_BLK
dd GPE1_BLK
db PM1_EVT_LEN

32. Firmware ACPI Control Structure (FACS)
FACS is a structure in read/write memory that the BIOS reserves for ACPI usage.
Hardware Signature
Used in waking from S4 state
Firmware_waking_Vector
Physical memory address of an OS wake function
Global_lock

33. dd 0 ;Hardware Signature dd 0 ;Firmware Waking Vector
Acpitbl.asm
;FACS Table
FACStable:
db "FACS" ;Signature
dd FACSLength ;Length
dd 0 ;Hardware Signature
dd 0 ;Firmware Waking Vector
dd 0 ;Global Lock
dd FACSFlag
db 40 dup (0) ;Reserved
FACSLength EQU ($-FACStable)

34. Differentiated System Description Table (DSDT)
DSDT is part of the system fixed description.
Table header
Data in Definition Block

36. ASL (ACPI Source Language)
ASL Name define
All name are a fixed 32 bits.
First byte is ‘A’-’Z’,’_’
Inclusive of ‘A’-’Z’,’0’-’9’,’_’
Name begin with ’_’ are reserved
Name proceeded with ‘\’ refer to the root
Name proceeded with ‘^’ refer to the parent

37. ASL Language Grammer
Multiple blanks are the same as one. Blank, (, ), ‘,’ and newline are all token separators.
// marks the beginning of a comment, which continues from the // to the end of the line.
/* marks the beginning of a comment, which continues from the /* to the next */.
“” surround an ASCII string.
Single quotes (‘ ’)Indicate constant characters.‘A’
Numeric constants can be written in three ways: ordinary decimal, octal (using 0ddd) or hexadecimal, using the notation 0xdd.
Nothing indicates an empty item. For example, { Nothing } is equivalent to {}.

38. ASL Data Type Description [Uninitialized]
No assigned type or value. This is the type of all control method LocalX variables and unused ArgX variables at the beginning of method execution, as well as all uninitialized Package elements. Uninitialized objects must be initialized (via Store or CopyObject) before they may be used as source operands in ASL expressions.
Buffer
An array of bytes. Uninitialized elements are zero by default.
Buffer Field
Portion of a buffer created using CreateBitField, CreateByteField, CreateWordField, CreateQWordField, CreateField, or returned by the Index operator.
DDB Handle
Definition block handle returned by the Load operator
Debug Object
Debug output object. Formats an object and prints it to the system debug port. Has no effect if debugging is not active.
Device
Device or bus object
Event
Event synchronization object
Field Unit (within an Operation Region)
Portion of an address space, bit-aligned and of one-bit granularity. Created using Field, BankField, or IndexField.
Integer
An n-bit little-endian unsigned integer. In ACPI 1.0 this was at least 32-bits. In ACPI 2.0 this is at least 64.bits.
Integer Constant
Created by the ASL terms “Zero”, “One”, “Ones”, and “Revision”.
Method
Control Method (Executable AML function)
Mutex
Mutex synchronization object
Object Reference
Reference to an object created using the RefOf operator
Operation Region
Operation Region (A region within an Address Space)
Package
Collection of ASL objects with a fixed number of elements (up to 255).
Power Resource
Power Resource description object
Processor
Processor description object
String
Null-terminated ASCII string with up to 200 characters.
Thermal Zone
Thermal Zone description object

39. ASL Language and Terms
DefinitionBlock( AMLFileName, //StringData TableSignature, //StringData ComplianceRevision, //ByteConst OEMID, //StringData TableID, //StringData OEMRevision //DWordConst ) {
ObjectList }

40. HEAD BODY W6555 Dsdt.asl DefinitionBlock ( "DSDT.AML", "DSDT", 0x01,
"INTELR", //OEMID
"AWRDACPI",
0x1000 )
{ // Start of ASL File
Scope(\_PR) {
Processor(\_PR.CPU0,
1, //processor number
0x4010, //System IO address of Pblk Registers
0x06 //length in bytes of PBlk
) {} } ……
Name(\_S0,Package(){0,0,0,0}) //R36
HEAD
BODY

41. Example // Define a control method power button
Device(\_SB.PWRB){ //_SB System bus scope
Name(_HID, EISAID(“PNP0C0C”)) //_HID hardware ID
Name(_PRW,Package(){0, 0x4}) //_PRW power resource for wake }
OperationRegion(\Pho, SystemIO, 0x200, 0x1)
Field(\Pho, ByteAcc, NoLock, WriteAsZeros){
PBP, 1, // sleep/off request
PBW, 1 // wakeup request
} // end of power button device object
//_Lxx /_Exx Control method executed as a result of a GPE
Scope(\_GPE){ // Root level event handlers //general-purpose event.
Method(_L00){ // uses bit 0 of GP0_STS register
If(PBP){
Store(One, PBP) // clear power button status
Notify(\_SB.PWRB, 0x80) // Notify OS of event
IF(PBW){
Store(One, PBW)
Notify(\_SB.PWRB, 0x2)
} // end of _L00 handler
} // end of \_GPE scope

42. Wake Sleep _PTS _GTS _WAK _BFS Prepare To Sleep Going To Sleep
System Wake
Back From Sleep

43. ACPI In BIOS

44. Relative files in source code
*.asx*.asl*.aml
ACPITBL.EXEACPITBL.BIN
ACPI.ASM
ACPI.EQU
ACPI.INC
ACPI_CT.INC
ACPI_IO.EQU
ACPIPOST.ASM
ACPITBL.ASM
ACPILED.ASXACPILED.ASL

46. ACPI Name space
A hierarchical tree structure in OS-controlled memory that contains named
objects. These objects may be data objects, control method objects,
bus/device package objects, and so on. The OS dynamically changes the
contents of the namespace at run-time by loading and/or unloading
definition blocks from the ACPI Tables that reside in the ACPI BIOS. All
the information in the ACPI Namespace comes from the Differentiated
System Description Table (DSDT), which contains the Differentiated
Definition Block, and one or more other definition blocks.
For all Definition Blocks, the system maintains a single hierarchical
namespace that it uses to refer to objects. All Definition Blocks load into
the same namespace.

47. Example ACPI NameSpace

50. W6555 Dsdt.asx \_PR \_S0 \_S1 \_S4 \_S5 \_PTS \_WAK \_SI _MSG _SST
\_SB
PWRB
_HID
_STA
SLPB
_PRW
PCI0
_ADR
_UID
_S3D
_CRS
PICM
APIC
_PRT
PX40
USB0
USB1
USB2
USB3
PX43
SMBB
MODM
PMIO
W6555
Dsdt.asx
\_PR
\_S0
\_S1
\_S4
\_S5
\_PTS
\_WAK
\_SI
_MSG
_SST
\_GPE
_L05
_L03
_L04
_L0B
_L08
_L1B
_L0C
_L0D
\_SB

51. BIOS Initialization Non-Volatile-Sleeping Memory(NVS) Boot Vector Yes
SLP_TYP=S3 ? No
Initialize CPU
Init memory controller
Enable Memory
Init chipset
Initialize CPU
Enable Memory
Yes
Restore Memory Image
S4BIOS ? No
POST …
ACPI NVS
ACPI Reclaim
ACPI Tables
Call Waking Vector
Boot OS Loader
Non-Volatile-Sleeping Memory(NVS)

52. SETUP ACPI TABLE ACPI memory range type: ACPI Reclaim Memory
Be free when finish using ACPI table
ACPI Non-Volatile-Sleeping Memory(NVS)
Reserved by BIOS

53. Process of Setup ACPI Table
Determine the size and address of the physical memory.
Allocate the ACPI Reserved area at top of memory for ACPI NVS and ACPI Reclaim memory areas.
Fix up the ACPI table pointers with address values.
Copy FACS into NVS;copy RSET,RACP,DSDT into ACPI Reclaim memory area;copy RSD pointer into E000:F000 memory segment.

55. cmp dword ptr ACPI_TABLE_FLAG[bp],0 jz short No_ACPI_table
E8post.asm
ifdef ACPI_Support
cmp dword ptr ACPI_TABLE_FLAG[bp],0
jz short No_ACPI_table
mov di,(ACPITBL_Expand_Address+1)*4
call POST_decompress
extrn SetupACPI:near
call SetupACPI ;call to setup ACPI table
No_ACPI_table:
endif; ACPI_Support

56. call SetRealModeLimit ;Enter big real mode
W6555
acpi.asm
call SetRealModeLimit ;Enter big real mode
F000_Call F000_Shadow_W ;Set F000 shadow to writeable
call GetACPIReclaimArea ;Return EAX=physical address of reclaim memory area
call MoveACPIToReclaim ;Move RSDT, FACP, DSDT tables to reclaim area
call GetACPINVSArea ;Return EAX=physical address of ACPI NVS area
call MoveACPItoNVS ;Move FACS table to NVS area.
call FillACPIAddress ;Fill in the pointers for all tables
call FillACPIChecksum ;Fill in check sum for all tables
call SetRealModelimit ;Leave big real mode

57. BOOTROM.ASM ACPI.ASM ACPITBL.ASM Detected system sleep resume state
Enable ACPI I/O space
Turn_On_ACPI_IO(chiprun.asm)
ACPI.ASM
Move codes to the top of memory,filled in all pointers,checksum.
ACPI Patch (Ct_parse_AML)
Replacesuspendtype PROC
ModifySuspendType PROC
ReplaceAML_String PROC
ACPITBL.ASM
All ACPI Tables puts here.

58. E0post.ASM E8post.ASM Setup INT15h function E820h – memory report
POST code 067h
Setup INT15h function E820h – memory report
ACPI table address & size
E8post.ASM
POST code 089h - SetupACPI
ACPI Table initialize
AML initialize
Dynamically modify ACPI tables and AML

59. Enable SCI to transfer to ACPI mode.
ACPI_ENABLE (0A1h)
out SMI_CMD,0A1H
Enable SCI to transfer to ACPI mode.
Save some chipset configuration.
ACPI_DISABLE (0A0h)
out SMI_CMD,0A0H
Disable SCI to transfer to Legacy mode.
Restore original chipset configuration.
S4BIOS_REQ (0A4h)
out SMI_CMD,0A4H
Save system context to heardisk and put system state to S4.

60. Questions How does OS get SCI information?
Is ACPI table dynamical created by BIOS Post?
Can modify ACPI table in OS?

61. THE END
Thank you