AT Keyboard Controller Emulation

This document describes the AT keyboard controller emulation implementation in the ACRN Device Model. The Atkbdc device emulates a PS2 keyboard and mouse.

Overview

The PS2 port is a 6-pin mini-Din connector used for connecting keyboards and mice to a PC-compatible computer system. Its name comes from the IBM Personal System/2 series of personal computers, with which it was introduced in 1987. PS2 keyboard/mouse emulation is based on ACPI emulation. We can add an ACPI description of the PS2 keyboard/mouse to the virtual DSDT table to emulate the keyboard/mouse in the User VM.

Figure 183 AT Keyboard Controller Emulation Architecture

PS2 Keyboard Emulation

ACRN supports an AT keyboard controller for PS2 keyboard that can be accessed through I/O ports (0x60 and 0x64). 0x60 is used to access the AT keyboard controller data register; 0x64 is used to access the AT keyboard controller address register.

PS2 keyboard ACPI description:

Device (KBD)
{
        Name (_HID, EisaId ("PNP0303") /* IBM Enhanced Keyboard (101/102-key, PS/2 Mouse) */) // _HID: Hardware ID
        Name (_CRS, ResourceTemplate () // _CRS: Current Resource Settings
        {
                IO (Decode16,
                    0x0060, // Range Minimum
                    0x0060, // Range Maximum
                    0x01, // Alignment
                    0x01, // Length
                    )
                IO (Decode16,
                    0x0064, // Range Minimum
                    0x0064, // Range Maximum
                    0x01, // Alignment
                    0x01, // Length
                    )
                IRQNoFlags ()
                   {1}
        })
}

PS2 Mouse Emulation

ACRN supports an AT keyboard controller for PS2 mouse that can be accessed through I/O ports (0x60 and 0x64). 0x60 is used to access the AT keyboard controller data register; 0x64 is used to access the AT keyboard controller address register.

PS2 mouse ACPI description:

Device (MOU)
{
        Name (_HID, EisaId ("PNP0F13") /* PS/2 Mouse */) // _HID: Hardware ID
        Name (_CRS, ResourceTemplate () // _CRS: Current Resource Settings
        {
                IO (Decode16,
                    0x0060, // Range Minimum
                    0x0060, // Range Maximum
                    0x01, // Alignment
                    0x01, // Length
                    )
                IO (Decode16,
                    0x0064, // Range Minimum
                    0x0064, // Range Maximum
                    0x01, // Alignment
                    0x01, // Length
                    )
                IRQNoFlags ()
                   {12}
        })
}