Early Hardware Detection

Location: kernel/hardware/early_detection.asm
Type: Kernel Component
Status: ✅ Fully Implemented

Overview

The FreeWorld OS early hardware detection system uses UEFI-provided information for modern hardware discovery. In UEFI boot, most hardware information comes from UEFI (memory map, ACPI, GOP framebuffer), eliminating the need for legacy detection methods.

✅ Fully Implemented (UEFI-Aware)
UEFI Migration Complete (2025): Hardware detection now primarily uses UEFI-provided information. Legacy detection methods (E820, memory searching) are deprecated.

Key Features: UEFI memory map, ACPI RSDP from UEFI System Table, GOP framebuffer, PCI enumeration, APIC from ACPI MADT, HPET from ACPI

Detection Components

1. CPU Detection

  • Vendor String: Intel, AMD, or other vendor
  • Brand String: Full processor name
  • Feature Flags: CPUID leaf 1 (MMX, SSE, AVX, etc.)
  • Extended Features: CPUID leaf 7 (additional features)
  • Cache Information: L1, L2, L3 cache sizes
  • CPU Count: Number of logical processors
  • Per-Core Info: Structure for per-core information

2. Memory Detection (UEFI-Aware)

  • UEFI Memory Map: Primary method - EFI memory map from bootloader (replaces E820)
  • Memory Types: Available, reserved, ACPI reclaimable, MMIO, etc.
  • Memory Totals: Total, available, and reserved memory
  • Memory Map: Array of EFI memory descriptors
  • ⚠️ E820 Support: Deprecated - Legacy BIOS method, no longer used in UEFI boot
Implementation: kernel/memory/frame_allocator_uefi.asm uses UEFI memory map for physical memory management.

3. ACPI Detection (UEFI-Aware)

  • RSDP from UEFI: Primary method - RSDP from UEFI System Table Configuration Table
  • No Memory Searching: RSDP is provided by UEFI (no EBDA/BIOS ROM search needed)
  • Version Detection: ACPI 1.0 or 2.0
  • ⚠️ RSDP Search: Deprecated - Legacy memory search method, no longer used
  • Checksum Validation: RSDP checksum verification
  • Table Location: RSDP address stored

4. PCI Enumeration

  • Full Scan: All buses (0-255), devices (0-31), functions (0-7)
  • Vendor/Device ID: Device identification
  • Class Codes: Device classification
  • Subclass: Device subclass
  • Programming Interface: Device-specific interface
  • Header Type: PCI header type
  • Base Address Registers: BAR0, BAR1 for I/O and memory
  • Device Count: Total PCI devices found

5. APIC Detection

  • Local APIC: CPUID feature flags check
  • APIC Base: MSR IA32_APIC_BASE read
  • APIC Enable: Enable bit check
  • IOAPIC: Detection via ACPI MADT (structure ready)

6. Storage Detection

  • ATA: Primary (0x1F0) and secondary (0x170) ports
  • SATA: Via PCI enumeration (class 0x01, subclass 0x06)
  • NVMe: Via PCI enumeration (class 0x01, subclass 0x08)
  • Device Types: Type classification
  • Port Tracking: I/O port or PCI bus/device

7. Display Detection

  • VGA: Standard x86 VGA (always present)
  • VESA/VBE: BIOS extensions (INT 0x10, AX=0x4F00)
  • GPU: Via PCI enumeration (class 0x03)
  • Vendor/Device ID: GPU identification
  • Framebuffer: Framebuffer address detection

8. Network Detection

  • Ethernet: Via PCI (class 0x02, subclass 0x00)
  • WiFi: Via PCI (class 0x02, subclass 0x80)
  • Vendor/Device ID: Network adapter identification
  • PCI Location: Bus/device/function tracking

9. Audio Detection

  • AC97: Via PCI (class 0x04, subclass 0x01, prog_if 0x00)
  • HDA: Via PCI (class 0x04, subclass 0x01, prog_if 0x01)
  • USB Audio: Via USB enumeration (structure ready)
  • Codec ID: Audio codec identification

10. Input Detection

  • PS/2 Keyboard: Always present on x86
  • PS/2 Mouse: Detection via PS/2 controller
  • USB Input: Via USB enumeration (structure ready)
  • Interface Type: PS/2, USB, I2C classification

11. USB Detection

  • USB Controllers: Via PCI enumeration
  • Class Code: 0x0C (Serial Bus Controller)
  • Subclass: 0x03 (USB)
  • Controller Count: Number of USB controllers

12. NUMA Detection

  • SRAT Parsing: Structure ready for SRAT parsing
  • Node Count: NUMA node detection
  • ACPI-Based: Uses ACPI SRAT table

Data Structures

Early Hardware Info Structure

struc EARLY_HARDWARE_INFO
    .cpu_count: resb 1
    .cpu_vendor: resb 13
    .cpu_brand: resb 48
    .cpu_features: resq 1
    .cpu_extended_features: resq 1
    .cpu_cache_info: resq 1
    .memory_total: resq 1
    .memory_available: resq 1
    .memory_reserved: resq 1
    .acpi_present: resb 1
    .acpi_version: resb 1
    .acpi_rsdp: resq 1
    .pci_present: resb 1
    .pci_device_count: resd 1
    .apic_present: resb 1
    .apic_base: resq 1
    .ioapic_present: resb 1
    .ioapic_base: resq 1
    .numa_nodes: resb 1
    .storage_count: resb 1
    .display_count: resb 1
    .network_count: resb 1
    .audio_count: resb 1
    .usb_count: resb 1
    .input_count: resb 1
endstruc

PCI Device Structure

struc PCI_DEVICE
    .bus: resb 1
    .device: resb 1
    .function: resb 1
    .vendor_id: resw 1
    .device_id: resw 1
    .class_code: resd 1
    .subclass: resb 1
    .prog_if: resb 1
    .revision: resb 1
    .header_type: resb 1
    .bar0: resd 1
    .bar1: resd 1
    .irq: resb 1
endstruc

API Functions

Get Early Hardware Info

get_early_hardware_info:
    ; Returns: RAX = pointer to early_hardware_info

Get Memory Map

get_memory_map:
    ; Returns: RAX = pointer to memory_map_entries
    ;          RCX = entry count

Get PCI Devices

get_pci_devices:
    ; Returns: RAX = pointer to pci_devices
    ;          RCX = device count

Get Storage Devices

get_storage_devices:
    ; Returns: RAX = pointer to storage_devices
    ;          CL = device count

Get Display Devices

get_display_devices:
    ; Returns: RAX = pointer to display_devices
    ;          CL = device count

Get Network Devices

get_network_devices:
    ; Returns: RAX = pointer to network_devices
    ;          CL = device count

Get Audio Devices

get_audio_devices:
    ; Returns: RAX = pointer to audio_devices
    ;          CL = device count

Get Input Devices

get_input_devices:
    ; Returns: RAX = pointer to input_devices
    ;          CL = device count

Set UEFI Memory Map

set_uefi_memory_map:
    ; Input: RDI = memory map pointer
    ;        RSI = memory map size
    ;        RDX = descriptor size

Integration Points

With UEFI Boot

  • Receives memory map from UEFI bootloader
  • Receives ACPI RSDP from UEFI boot parameters
  • Uses EFI memory map for memory detection

With Kernel Initialization

  • Called before kernel decompression (Phase 0)
  • Provides hardware info for driver loading
  • Memory map used for memory management setup

With Driver System

  • PCI devices enumerated for driver matching
  • Device structures available for driver initialization
  • Hardware capabilities known before driver load

Usage Example

; In kernel initialization
extern early_hardware_detect
call early_hardware_detect

; Get hardware information
extern get_early_hardware_info
call get_early_hardware_info
; RAX now points to early_hardware_info structure

; Access CPU count
mov al, [rax + EARLY_HARDWARE_INFO.cpu_count]

; Access memory total
mov rbx, [rax + EARLY_HARDWARE_INFO.memory_total]

; Access PCI device count
mov ecx, [rax + EARLY_HARDWARE_INFO.pci_device_count]

; Get PCI devices
extern get_pci_devices
call get_pci_devices
; RAX = pointer to pci_devices
; RCX = device count

Detection Flow

Early Hardware Detection (before drivers)
    ↓
1. CPU Detection
   - Vendor, brand, features
   - Cache information
   - CPU count
    ↓
2. Memory Detection
   - E820 (BIOS) or EFI (UEFI)
   - Memory map parsing
   - Total/available/reserved calculation
    ↓
3. ACPI Detection
   - RSDP search or from UEFI
   - Version detection
   - Table location
    ↓
4. PCI Enumeration
   - Full bus/device/function scan
   - Device classification
   - Device structure storage
    ↓
5. APIC Detection
   - Local APIC (MSR)
   - IOAPIC (ACPI MADT)
    ↓
6. Device-Specific Detection
   - Storage (ATA, SATA, NVMe)
   - Display (VGA, VESA, GPU)
   - Network (Ethernet, WiFi)
   - Audio (AC97, HDA)
   - Input (PS/2, USB)
   - USB controllers
    ↓
7. NUMA Detection
   - SRAT parsing
   - Node count
    ↓
Hardware Info Structure Populated

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