Book Image

Linux Device Drivers Development

By : John Madieu
Book Image

Linux Device Drivers Development

By: John Madieu

Overview of this book

Linux kernel is a complex, portable, modular and widely used piece of software, running on around 80% of servers and embedded systems in more than half of devices throughout the World. Device drivers play a critical role in how well a Linux system performs. As Linux has turned out to be one of the most popular operating systems used, the interest in developing proprietary device drivers is also increasing steadily. This book will initially help you understand the basics of drivers as well as prepare for the long journey through the Linux Kernel. This book then covers drivers development based on various Linux subsystems such as memory management, PWM, RTC, IIO, IRQ management, and so on. The book also offers a practical approach on direct memory access and network device drivers. By the end of this book, you will be comfortable with the concept of device driver development and will be in a position to write any device driver from scratch using the latest kernel version (v4.13 at the time of writing this book).
Table of Contents (23 chapters)
Free Chapter
1
Introduction to Kernel Development

Memory allocation mechanism

Let's look at the following diagram, showing us the different memory allocators that exist on a Linux-based system, and discuss it later. (inspired by http://free-electrons.com/doc/training/linux-kernel/linux-kernel-slides.pdf):

Overview of kernel memory allocator

There is an allocation mechanism to satisfy any kind of memory request. Depending on what you need memory for, you can choose the one closest to your goal. The main allocator is the Page Allocator, which only works with pages (a page being the smallest memory unit it can deliver). Then comes the SLAB Allocator which is built on top of the page allocator, getting pages from it and returning smaller memory entities (by mean of slabs and caches). This is the allocator on which the kmalloc Allocator relies.

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