diff --git a/hw/pm_smbus.h b/hw/pm_smbus.h
new file mode 100644
index 0000000..4750a40
--- /dev/null
+++ b/hw/pm_smbus.h
@@ -0,0 +1,21 @@
+#ifndef PM_SMBUS_H
+#define PM_SMBUS_H
+
+typedef struct PMSMBus {
+    i2c_bus *smbus;
+
+    uint8_t smb_stat;
+    uint8_t smb_ctl;
+    uint8_t smb_cmd;
+    uint8_t smb_addr;
+    uint8_t smb_data0;
+    uint8_t smb_data1;
+    uint8_t smb_data[32];
+    uint8_t smb_index;
+} PMSMBus;
+
+void pm_smbus_init(DeviceState *parent, PMSMBus *smb);
+void smb_ioport_writeb(void *opaque, uint32_t addr, uint32_t val);
+uint32_t smb_ioport_readb(void *opaque, uint32_t addr);
+
+#endif /* !PM_SMBUS_H */