Writing Device Drivers for HelenOS

Overview of Drivers in HelenOS

DDF (Device Driver Framework)

DDF Driver Structure

• #include <ddf/driver.h>
• driver_t
• driver_ops_t
• ddf_dev_ops_t

Device and Function Life Cycle

• ddf_fun_create()
• ddf_fun_destroy()
• ddf_fun_add_match_id()
• ddf_fun_add_to_category()
• ddf_fun_bind()
• ddf_fun_unbind()
• ddf_fun_online()
• ddf_fun_offline()

Soft State Management

• ddf_dev_data_alloc()
• ddf_fun_data_alloc()

Exposing Driver Services to Clients

Traditional I/O Device Drivers

Programmed I/O

Interrupts

DMA

USB Device Drivers