Advanced Configuration and Power Interface Specification

ACPI Software Programming Model
// Create the GenericSerialBus data buffer as BUFF
Name(BUFF, Buffer(34)())
// Create GenericSerialBus data buffer as BUFF
CreateByteField(BUFF, 0x00, STAT) // STAT = Status (Byte)
CreateByteField(BUFF, 0x01, LEN) // LEN = Length (Byte)
CreateWordField(BUFF,0x02, DATW) // Data (Bytes 2 and 3)
CreateField(BUFF, 0x10, 256, DATA) // Data (Block)
Store(0x0B,DATW)
//Store appropriate reference data for driver to interpret
// Process Call with input value "ACPI" to the device
Store("ACPI", DATA)
// Fill in outgoing data
Store(8, LEN)
// Length of the valid data
Store(Store(BUFF, FLD0), BUFF) // Execute the PC
if (LEqual(STAT, 0x00))
// Test the status
{
// BUFF now contains information returned from PC
// LEN now equals size of data returned
}
Raw accesses assume that the writer has knowledge of the bus that the access is made over and the
device that is being accessed. The protocol may only ensure that the buffer is transmitted to the
appropriate driver, but the driver must be able to interpret the buffer to communicate to a register.
5.6 ACPI Event Programming Model
The ACPI event programming model is based on the SCI interrupt and General-Purpose Event
(GPE) register. ACPI provides an extensible method to raise and handle the SCI interrupt, as
described in this section.
Hardware-reduced ACPI platforms (Section 4.1) use GPIO Interrupt Connections to signal ACPI
Events, described in Section 5.6.5.
5.6.1 ACPI Event Programming Model Components
The components of the ACPI event programming model are the following:
• OSPM
• FADT
• PM1a_STS, PM1b_STS and PM1a_EN, PM1b_EN fixed register blocks
• GPE0_BLK and GPE1_BLK register blocks
• GPE register blocks defined in GPE block devices
• SCI interrupt
• ACPI AML code general-purpose event model
• ACPI device-specific model events
• ACPI Embedded Controller event model
The role of each component in the ACPI event programming model is described in the following
table.
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