Introduction: from 2.4 to 2.6, the Linux kernel has greatly changed in terms of the module mechanism, device model, and some core APIs that can be loaded, device driver developers are faced with porting drivers from 2.4 to 2.6 kernels, or enabling drivers to support both 2.4 and 2.6 kernels... news nbsp
Introduction: from 2.4 to 2.6, the
Distory function*/
int Cleanup_module ()
{
PRINTK ("I'll shut down myself in Kernerl mod/n)";
RETUTN 0;
}Such an example is done. We also write a makefile example to fit our application in large program heavy applications. This is the content of the Makfile file.
# A Makefile for a module
cc=gcc
modcflags:=-wall _dmodule-d_kernel_-dlinux
HELLO.O Hello.c/usr/inculde? Linux/version.h
CC $ (modcflags) 0c hello.c
echo the module is Complie completely
The
of the LCD controller.
Specifically:
Fill in a fbinfo Structure
Use reigster_framebuffer (fbinfo *) to register the fbinfo structure to the kernel
For the fbinfo structure, the most important thing is its fs_ops member. You need to implement interfaces in fs_ops for specific devices.
Whether to use interrupt handling
Memory Access
If the video card does not have its own video memory, the system memory is allocated as the video memory.
The graphics card comes with a vide
The driver can be compiled in two ways. One is to statically compile the program into the kernel, and the other is to compile the program into a module for dynamic loading. Because uClinux does not support dynamic module loading, and embedded Linux cannot use insmod/rmmod as flexibly as Desktop Linux does, so here we will only introduce how to statically compile the device driver into the uClinux kernel.The
multiplier effect. In fact, many well-known companies to recruit the topic, a lot of it from this book, it can be seen that it is really a description of the Linux Kernel classic books.Linux device driver, Corbett"Linux device Drivers", recommended index: ★ ¡ïprogram development, high salary in Linux,
) + + hello/When Config_hello is Y or M, the system can find the Hello-driven makefile.
Under the linux-2.6.25 directory, make menuconfig, select the Hello Driver added by Dong item, such as M, under the device Drivers menu as module. Then save the configuration, execute make command, you can see the CC [M] drivers/hello/hello.o log, the Hello directory generate
version
When the device driver needs to support different kernel versions at the same time, in the compilation phase, the kernel module needs to know the version of the currently used kernel source code to use the corresponding kernel API. In the 2.4 and 2.6 kernels, the source code header file Linux/version. H is defined as follows:
Linux_version_code: the binary representation of the kernel version. Each of the primary, slave, and revision versions
Article title: device drivers in LINUX. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.
3. device drivers in UNIX systems
3.1 Basic s
The function of counting the number of words is encapsulated in the Linux driver. The Linux system maps each driver into a single file. These files are called device files or drive files and are stored in the/dev directory. The steps for writing a Linux driver are as follows:1. Build Linux drive skeleton (load and unlo
Linux-driven work and access is one of the highlights of Linux, and has been widely praised by the industry. The Linux system maps each driver into a single file. These files are called device files or drive files.To write a Linux driver:First step: Build Linux driver skelet
Introduction plan for linux Device Drivers-general Linux technology-Linux programming and kernel information. For details, see the following section. Ldd2, that is, linux device driver 2nd. This book helps you understand the implementation of most hardware work through the
In the Linux kernel, The framebuffer (POST buffer) driver is the display driver standard. framebuffer abstracts the display device as the POST buffer. After the user maps the memory to the process address space, you can directly perform read/write operations, and write operations can be immediately displayed on the screen. Related display drivers and interfaces are available in
.
Specifically:
Fill in a fbinfo Structure
Use reigster_framebuffer (fbinfo *) to register the fbinfo structure to the kernel
For the fbinfo structure, the most important thing is its fs_ops member. You need to implement interfaces in fs_ops for specific devices.
Whether to use interrupt handling
Memory Access
If the video card does not have its own video memory, the system memory is allocated as the video memory.
The graphics card comes with a vide
int Dma_map_device (struct device *dev,struct scatterlist *sg, int nents,enum dma_data_directiondirection);
There can be a relatively simple way to pre-allocate buffers in a Linux system, which is to synchronize the "mem=" parameter to reserve memory. For example, for a system with a memory of 64MB, passing the MEM=62MB command-line argument to it allowsThe top 2MB memory is reserved for use as IO memory, this 2MB memory can be statica
Starting with 2.6.13-RC3, the Linux kernel provides the ability to dynamically bind and Unbind devices and device drivers in user space. Prior to this, the insmod can only be bound and reconciled through the modprobe and rmmod, and this binding and bundling is for the driver and all devices. The new feature can set the connection between the driver and the individual device.Here, we take the NVMe SSD for PC
1. Get the kernel version
When the device driver needs to support different kernel versions at the same time, in the compilation phase, the kernel module needs to know the version of the currently used kernel source code to use the corresponding kernel API. In the 2.4 and 2.6 kernels, the source code header file Linux/version. H is defined as follows:
Linux_version_code: the binary representation of the kernel version. Each of the primary, slave, and
Note: a good article on understanding PCI devices and PCI drivers
To understand the Linux PCI device driver, first understand that the so-called Linux PCI device driver actually includes the Linux PCI device driver and the device driver. I do not know whether the reader understands this sentence. I think this sentence
!Released on: February 1, February 09, 2006Level: elementaryAccess status: 3751 viewsSuggestion: 0 (add comments)
1. Get the kernel versionWhen the device driver needs to support different kernel versions at the same time, in the compilation phase, the kernel module needs to know the version of the currently used kernel source code to use the corresponding kernel API. In the 2.4 and 2.6 kernels, the source code header file linux/version. h is defined
First, the steps to write a Linux driver1. Build Linux Drive skeleton: that is, load and unload Linux drivers. In the Linux driver, you need to provide two functions to handle the operation of the driver initialization and exit separately. These two functions are specified b
Recently read a lot of kernel programming and drive development tutorials, also refer to some of the Development Board examples. The conclusion is not as high as you can imagine. Developing a driver requires a certain understanding of the kernel, not a thorough interpretation.
The drivers referred to below are for specific devices and are made to work in dynamic loading of modules. The driver framework is layered, some
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