Just focus on how to actually use the UIO driver and the most important function calls mmap(), read(), and write(). You can ignore anything that refers to writing your own kernel driver as we are not doing that. Make sure you read the short section on this variant: uio_pdrv_genirq. This UIO variant is designed for embedded systems, and provides a generic interrupt handler. In this class we are using the uio_pdrv_genirq variant (UIO, Platform Driver, Generic IRQ). Linux provides a number of UIO variants, for different types of devices that a system might contain. The UIO device files for each hardware device are listed on the Software Stack page. You can gain a virtual address pointer to the device by using mmap() on the UIO device file for the device. Since Linux uses a virtual address system, you cannot directly access the physical addresses of devices. At minimum, read the section on How UIO works.įor this class we will use the UIO for two purposes: See the Software Stack page.ĭocumentation of the UIO is available here. In the system you are given in this class, the buttons, LEDs, switches and interrupt controller are all accessed via UIO. In Linux, user programs cannot access hardware directly so the UIO bridges this gap. The purpose of the driver is to act as a thin layer between user space programs and the hardware. The UIO is a general purpose kernel driver that can be accessed from user space.

How to install uio