diff --git a/include/drivers/io_driver.h b/include/drivers/io_driver.h
index cc01d3b..f34c71d 100644
--- a/include/drivers/io_driver.h
+++ b/include/drivers/io_driver.h
@@ -39,7 +39,7 @@
 /* Generic IO entity structure,representing an accessible IO construct on the
  * device, such as a file */
 typedef struct io_entity {
-	io_dev_handle dev_handle;
+	struct io_dev_info *dev_handle;
 	uintptr_t info;
 } io_entity_t;
 
@@ -47,7 +47,7 @@
 /* Device info structure, providing device-specific functions and a means of
  * adding driver-specific state */
 typedef struct io_dev_info {
-	struct io_dev_funcs *funcs;
+	const struct io_dev_funcs *funcs;
 	uintptr_t info;
 } io_dev_info_t;
 
@@ -55,23 +55,23 @@
 /* Structure used to create a connection to a type of device */
 typedef struct io_dev_connector {
 	/* dev_open opens a connection to a particular device driver */
-	int (*dev_open)(void *spec, io_dev_info_t **dev_info);
+	int (*dev_open)(const uintptr_t dev_spec, io_dev_info_t **dev_info);
 } io_dev_connector_t;
 
 
 /* Structure to hold device driver function pointers */
 typedef struct io_dev_funcs {
 	io_type_t (*type)(void);
-	int (*open)(io_dev_info_t *dev_info, const void *spec,
+	int (*open)(io_dev_info_t *dev_info, const uintptr_t spec,
 			io_entity_t *entity);
 	int (*seek)(io_entity_t *entity, int mode, ssize_t offset);
 	int (*size)(io_entity_t *entity, size_t *length);
-	int (*read)(io_entity_t *entity, void *buffer, size_t length,
+	int (*read)(io_entity_t *entity, uintptr_t buffer, size_t length,
 			size_t *length_read);
-	int (*write)(io_entity_t *entity, const void *buffer,
+	int (*write)(io_entity_t *entity, const uintptr_t buffer,
 			size_t length, size_t *length_written);
 	int (*close)(io_entity_t *entity);
-	int (*dev_init)(io_dev_info_t *dev_info, const void *init_params);
+	int (*dev_init)(io_dev_info_t *dev_info, const uintptr_t init_params);
 	int (*dev_close)(io_dev_info_t *dev_info);
 } io_dev_funcs_t;
 
@@ -79,7 +79,7 @@
 /* IO platform data - used to track devices registered for a specific
  * platform */
 typedef struct io_plat_data {
-	io_dev_info_t *devices[MAX_IO_DEVICES];
+	const io_dev_info_t *devices[MAX_IO_DEVICES];
 	unsigned int dev_count;
 } io_plat_data_t;
 
@@ -90,6 +90,6 @@
 void io_init(io_plat_data_t *data);
 
 /* Register a device driver */
-int io_register_device(io_dev_info_t *dev_info);
+int io_register_device(const io_dev_info_t *dev_info);
 
 #endif  /* __IO_DRIVER_H__ */