Linux is an open-source operating system that can be used as a platform to run desktop apps, servers, and embedded software. Due to its modular open-source nature, it can offer great flexibility and diversity. In comparison to other operating systems, it provides lots of technical advantages.
As a result, it is extensively implemented in several spheres, varying from businesses of all sizes to governmental bodies. It can be used on supercomputers, laptops, tablets, smartphones, and other digital devices.
A properly developed device driver ensures the smooth functioning of the system. In this article, we will examine the basic technical characteristics that can help you with device driver development.
Introduction to Linux Kernel Development
Being the central item of an OS, it functions as the main interface between the hardware and its processes. The kernel manages all the pivotal operations of any kind of device. The question of how to develop device drivers with the help of a firmware development company is gaining traction, caused by the skyrocketing popularity of Linux OS.
The kernel operates in the kernel space, not visible to the users. Users can observe only user-space — web browsers and files, which interact with the kernel through the system call interface.
Major functions of Linux kernel:
- Management of all the hardware resources: CPU, memory, I/O
- Providing a set of portable, architecture and hardware-independent APIs
- Control of all system processes
- Handling concurrent accesses and usage of hardware resources from different apps
- Receiving system requests and ensuring security
Major Advantages of Linux Kernel
Known as a well-protected OS, Linux helps in supporting your safety and keeping your confidential information safe. All the layers help improve the level of protection against cybercriminals. Hacker and viral attacks on the systems are comparatively rare thanks to these features. Another reason is that not all users are granted admin access to the system automatically.
From time to time, all systems can encounter minor errors or bugs. Thanks to comprehensive testing before the release, and regular upgrading, Linux is renowned for its durability and steadiness.
Due to its open-source licensing nature, customers do not have to pay money for its downloading, installing, and subsequent use. What is more, it implies that users can become valuable contributors to the Linux system and carry out the examination of code and its functionalities. To enhance the technological capacity of your infrastructure, you can load a variety of programs for free as well.
In case users have a good understanding of basic principles of usage, it will be simple enough to handle the system every day. Learning fundamentals is essential to grasp the most important features so that you can customize the system and employ all the available instruments ready at hand.
You are absolutely free to take any necessary decision that you think is fit. This gives you significant independence over customization and tweaking the system based only on your own preferences, without stint, and only the sky’s the limit.
The Linux ecosystem is undemanding and remains resourceful even under the conditions of implementing heavyweight PC.
Wise Resource Allocation
Being a highly-efficient solution, Linux does not require lots of space. In fact, it can function pretty well even when there is limited empty space, without affecting its robust performance.
As an incredibly privacy-friendly solution that an established firmware development company can offer, Linux will not hoard your personal data and behavioral patterns for targeting purposes.
Many users consider one of the most significant advantages to be the easy installation process.
Unlike its competitors, Linux device driver programming provides quick updating opportunities, with the annual release of a new version, which allows updating the current one without its deinstallation.
Allocation and Initialization of Kernel Structures
The kernel always offers two possible allocation mechanisms for its data structures and facilities.
Examples of kernel structures:
Dynamical initializers are macros and you should write them in capital letters.
Data structures representing framework devices should be allocated dynamically. Each data structure has its own allocation API.
The examples of framework device types:
- Input device
- Char device
- IIO device
- PWM device
Static objects are visible by the driver and all the devices that are managed by the driver. If the objects are dynamically allocated, they are visible only to the devices that use the provided module instance.
Linux Coding Style
The coding style is a personal choice of every developer. Further, we will explore some of the most commonly accepted coding style features.
Short Code Lines
It’s important to keep your code readable and maintainable. Make sure the length of your code lines does not exceed the preferable 80 columns.
Linux uses C programming language, so try to avoid too intricate and long names written in mixed cases, and provide simple and concise names, especially for your local functions. In case of a global variable, give it a descriptive naming.
Keep your functions short. They shouldn’t comprise more than five-ten local variables, as it is easier for the correct perception.
In comments, don’t explain how your code works, but rather focus on what it does, and, in some cases, why it does it.
Reference Counts for Data Structures
If data structures are visible beyond the pale of the single-threaded environment where they are created and destroyed, they must have reference counts. If another thread happens to find data structures without reference counts on them, it means the error in the program.
Take a look at some basic rules for kernel messaging below
- Make sure you spell the words in the kernel messages correctly.
- Keep away from ambiguous words, convey the meaning explicitly.
- Avoid terminating messages with a period.
- Do not print numbers in parentheses.
Programmers often consider inlines in gcc to be a magical tool for increasing the speed. However, bear in mind that the excessive use of inlines causes a bigger kernel, and, as a result, the program performs slower.
You can implement inline assembly in the interface with CPU or platform functionality in the coding with specific architecture.
In this article, we have studied the characteristics of Linux device driver development, learned Linux coding style peculiarities, and examined the trustworthy sources that can help in Linux development. Highly efficient performance of Linux device drivers will help establish better workflows, more effective business processes, and boost customer satisfaction with your services.