// HAL PCI configuration access. This file owns legacy mechanism-1 PCI config port I/O.

#include <stdint.h>
#include <ntlite/ddi/hal_api.h>

#define PCI_CONFIG_ADDR  0xCF8
#define PCI_CONFIG_DATA  0xCFC

// Creates addr.
static uint32_t MakeAddr(uint8_t bus, uint8_t dev, uint8_t fn, uint16_t offset) {
    return 0x80000000UL
         | ((uint32_t)bus << 16)
         | ((uint32_t)(dev & 0x1F) << 11)
         | ((uint32_t)(fn  & 0x07) <<  8)
         | ((uint32_t)offset & 0xFCu);
}

static uint32_t PciRead32(uint16_t segment,
                          uint8_t bus,
                          uint8_t dev,
                          uint8_t fn,
                          uint16_t offset) {
    if (segment != 0 || offset > 0xFCu)
        return 0xFFFFFFFFu;

    __outdword(PCI_CONFIG_ADDR, MakeAddr(bus, dev, fn, offset));
    return __indword(PCI_CONFIG_DATA);
}

static void PciWrite32(uint16_t segment,
                       uint8_t bus,
                       uint8_t dev,
                       uint8_t fn,
                       uint16_t offset,
                       uint32_t value) {
    if (segment != 0 || offset > 0xFCu)
        return;

    __outdword(PCI_CONFIG_ADDR, MakeAddr(bus, dev, fn, offset));
    __outdword(PCI_CONFIG_DATA, value);
}

// Implements the pci Initialize operation.
void HalPciInitialize(HAL_PCI* out) {
    out->Read32  = PciRead32;
    out->Write32 = PciWrite32;
}