Add interfaces for PCI host and PCI device.

devices/pcidevice.h

@@ -0,0 +1,34 @@
+#ifndef PCI_DEVICE_H
+#define PCI_DEVICE_H
+
+#include <cinttypes>
+#include <string>
+#include "mmiodevice.h"
+#include "pcihost.h"
+
+/* convert little-endian DWORD to big-endian DWORD */
+#define LE2BE(x) (x >> 24) | ((x & 0x00FF0000) >> 8) | ((x & 0x0000FF00) << 8) | (x << 24)
+
+enum {
+    CFG_REG_BAR0 = 0x10 // base address register 0
+};
+
+
+class PCIDevice : public MMIODevice {
+public:
+    PCIDevice(std::string name) {this->name = name;};
+    virtual ~PCIDevice() = default;
+
+    /* configuration space access methods */
+    virtual uint32_t pci_cfg_read(uint32_t reg_offs, uint32_t size) = 0;
+    virtual void     pci_cfg_write(uint32_t reg_offs, uint32_t value, uint32_t size) = 0;
+
+    virtual void set_host(PCIHost *host_instance) = 0;
+
+protected:
+    std::string   name; // human-readable device name
+    PCIHost *host_instance; // host bridge instance to call back
+    uint32_t base_addr; // base address register 0
+};
+
+#endif /* PCI_DEVICE_H */

devices/pcihost.h

@@ -0,0 +1,15 @@
+#ifndef PCI_HOST_H
+#define PCI_HOST_H
+
+#include <cinttypes>
+
+class PCIDevice; // forward declaration to prevent errors
+
+class PCIHost {
+public:
+    virtual bool pci_register_device(int dev_num, PCIDevice *dev_instance) = 0;
+    virtual bool pci_register_mmio_region(uint32_t start_addr, uint32_t size,
+        PCIDevice *obj) = 0;
+};
+
+#endif /* PCI_HOST_H */