Dynamic memory allocation in Device Driver by Kmalloc and Vmalloc In this chapter we will discuss about memory allocation in Linux device drivers, kmalloc and vmalloc , what are the differences between kmalloc and vmalloc, when to use kmalloc and vmalloc. While writing device drivers we might need to allocate …
CPU connects to multiple external devices like LCD, Hard Disks etc. CPU used for sending and receiving data to/from the devices. Data rate for this transaction might vary from bits to gigabytes . Process of transaction of data between CPU and Devices, CPU supports multiple ports which are called IO …
Linux Device driver MMAP() We have Discussed Architecture of Linux Operating System (==>) in our previous Linux Device Tutorials . Now You must be knowing that every device in Linux operating system is represented as a Device file . This device file is just like the other files which can …
Module Parameters In previous chapter we discussed about kernel modules http://www.tutorialsdaddy.com/courses/linux-device-driver/8486-linux-kernel-module/ and there features . So when we write any kernel module, we might need to pass some information to module at the time of loading modules And these parameters might vary from system to system. Fortunately Linux kernel provides us …
Now we have understood like what is device driver, basic components of device drivers ,functionality of device driver. As we have in almost every driver have basic functions support like open, close , read and write. Besides of these generic function every driver may have their own particular functionality exposed to user …
In this chapter we will discuss about Loadable kernel modules. We will understand what are Loadable kernel modules, why Loadable kernel modules were introduced, what are the benefits of kernel modules, what are the usage of Loadable kernel modules and how Loadable kernel modules are different with user space modules. …
In this chapter we will discuss about Loadable kernel modules. We will understand what are Loadable kernel modules, why Loadable kernel modules were introduced, what are the benefits of kernel modules, what are the usage of Loadable kernel modules and how Loadable kernel modules are different with user space modules. …
In this article we will write a character driver which will support various function like open, close , read and write. In basic character driver structure as we have discussed the components of a driver. following are the steps to write a character driver. 1) write character driver code:- character …
“Hello World” driver In this article we will be writing simple character driver and will hook this character driver in our running kernel of your Linux machine. As we discussed about multiple component of a character driver. If we put all component together our code looks like below image and …
Driver Generic structure Basic structure of driver for every device is similar for every device. We can divide driver structure in following sections. 1) Init and Exit Calls 2) fops structure 3)Interrupt Routine lets discuss in brief about each section. 1) Init and Exit Calls As we already discussed that …