Add Pci enumeration files

src/pci.c

+// pci.c
+//
+// Contains implementations of the functions for dealing with PCI
+// defined in pci.h
+
+#include "pci.h"
+#include "serial.h"
+
+// reads a word from the io port using the pci addressing scheme
+uint16_t pciConfigReadWord(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset)
+{
+    uint32_t address;
+    uint32_t lbus  = (uint32_t)bus;
+    uint32_t lslot = (uint32_t)slot;
+    uint32_t lfunc = (uint32_t)func;
+
+    address = (uint32_t)((lbus << 16) |
+                         (lslot << 11) |
+                         (lfunc << 8) |
+                         (offset & 0xfc) |
+                         ((uint32_t)0x80000000));
+    outl(PCI_CONFIG_OUT, address);
+
+    // return the contents of the address clipped
+    return (uint16_t)((inl(0xCFC) >> ((offset & 2) * 8)) & 0xffff);
+}
+
+// Check function also prints out stuff
+void checkFunction(uint8_t bus, uint8_t device, uint8_t function) {
+    uint16_t class;
+
+    class = pciConfigReadWord(bus, device, function, 0x08);
+
+    // Print out information about the device
+    serial_writestring("0x");
+    serial_hexhword(class);
+    serial_writestring(" on bus ");
+    serial_hexbyte(bus);
+    serial_writestring(" device ");
+    serial_hexbyte(bus);
+    serial_writestring(" function ");
+    serial_hexbyte(function);
+    serial_writestring("\n");
+}
+
+void checkDevice(uint8_t bus, uint8_t device)
+{
+    uint8_t function = 0;
+
+    uint16_t vendorID = pciConfigReadWord(bus, device, function, 2);
+    if (vendorID == 0xFFFF)
+    {
+        return;
+    }
+
+    checkFunction(bus, device, function);
+    uint8_t headerType = (pciConfigReadWord(bus, device, function, 0x0C) & 0xff00) >> 8;
+    if( (headerType & 0x80) != 0)
+    {
+        // It is a multi-function device, so check remaining functions
+        for(function = 1; function < 8; function++)
+        {
+            if(pciConfigReadWord(bus, device, function, 2) != 0xFFFF)
+            {
+                checkFunction(bus, device, function);
+            }
+        }
+    }
+}
+
+
+void checkAllBuses(void)
+{
+    uint8_t bus;
+    uint8_t device;
+
+    for(bus = 0; bus < 255; bus++)
+    {
+        for(device = 0; device < 32; device++)
+        {
+            checkDevice(bus, device);
+        }
+    }
+}

src/pci.h

+// pci.h
+//
+// Contains headers for functions related to dealivg with PCI
+
+#ifndef _PCI_INC
+#define _PCI_INC
+
+#include <stdint.h>
+
+#include "asm.h"
+
+#define PCI_CONFIG_OUT 0xCF8
+#define PCI_CONFIG_IN 0xCF8
+
+uint16_t pciConfigReadWord(uint8_t bus, uint8_t slot, uint8_t func, uint8_t offset);
+
+uint16_t pciCheckVendor(uint8_t bus, uint8_t slot);
+
+void checkAllBuses(void);
+
+#endif