This document describes how to use ctl_code to communicate with a Windows NT driver. generally, user-Mode Applications can communicate with kernel-mode drivers by calling createfile and deviceiocontrol, if a driver in the kernel state wants to perform similar operations with another driver, how can this problem be achieved? Next, we will provide a detailed description.
The main idea is to first get the hand
. These are common for all RTC, and only the underlying implementation is device-related. Therefore, drivers/RTC/rtc-dev.c realizes the RTC driver generic character device driver layer, which implements the file_opearations member function and some general control code about RTC, export rtc_device_register () and rtc_device_unregister () to the underlying layer f
interaction module, he external to the operating system API, no longer give application software engineer directly interface.Then we have to ask, with the operating system, the driver becomes complex, then what does the operating system do?First, a complex software system needs to handle multiple concurrent tasks, without operating systems, and it is difficult to accomplish multitasking.Second, the operating system provides us with a memory management mechanism. A typical example is that, for m
the operating system API, no longer give application software engineer directly interface.Then we have to ask, with the operating system, the driver becomes complex, then what does the operating system do?First, a complex software system needs to handle multiple concurrent tasks, without operating systems, and it is difficult to accomplish multitasking.Second, the operating system provides us with a memory management mechanism. A typical example is that, for most processors with MMU,
!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
entire drive from the compilation to the test program to test the whole process, need to master the various operational commands 1. In globalmen this directory, make a first, GLOBALMEM.C compiled into modules Globalmem.ko 2. Lsmod See if this Linux has globalmem module 3.insmod globalmem.ko load globalmem module 4.lsmod See if load succeeded 5.cat/proc/ Devices view the device that is generated when the driver is loaded (the proc directory is a
pse tsc msr pae mce cx8 APIC mtrr pge mca cmov Pat limit 36 MMX fxsr SSE syscall mmxext 3 dnowext 3 dnow
Bogomips: 2998.27
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/Proc/devices File
This file lists the characters and main device numbers of Block devices, and the names of devices allocated to these device numbers.
Example:
[Root @ localhost/] # Cat/proc/devices
Chara
Level 1)
Basic knowledge:
Understand the role of a device driver as a function module in LinuxOS and its position in the entire hybrid body,
The concepts and usage of Linux kernel loaded modules are clarified. In Chap11, the implementation policies of kernel module mechanisms are also given.
Chapter 1. An Introduction to Device Drivers
Chapter 2. Building and
Chapter 1 2: An Introduction to device driver building and running modules
1. Concurrent, security -- module writting notes
2. Kernel stack is small, normally one page (4 K). So don't create a lot of local variables and don't have a long call stack.
3. kernel can't handle float pointing computing.
4. Compiling Build:
OBJ-M: = module. o
Module-objs: = file1.o file2.o
Make-C ~ /Kernel-2.6 m = 'pwd' modules
5./proc/modules saves all modules load. lsmo
communication mode development and precautions
Serialization | Iot framework ServerSuperIO tutorial-7. Self-control communication mode development and precautions
Serialization | Iot framework ServerSuperIO tutorial-8. single-instance communication mode development and precautions
Serialization | Iot framework ServerSuperIO tutorial-9. protocol filter to solve multiple packet-related, sticky packet, and redundant data
Serialization | Iot framework ServerSuperIO tutorial-
blocking and non-blocking IO in Linux device drivers:Blocking and non-blocking in 1.Linux device drivers Summary: http://m.blog.csdn.net/blog/dongteen/17264501Blocking and non-blocking io:http://m.blog.csdn.net/blog/dongteen/17264501 in 2.Linux device driversBlocking and non-blocking I/O in 3.Linux
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 Linux kernel/Linux/
holds the processor context snapshot before the processor enters the interrupt code
The interrupt processing routine should return a value that indicates whether an interrupt was actually handled, and if the processing routine finds that its device does need to be processed, it should return irq_handled, otherwise the return value should be Irq_none
Enable and disable interrupts
sometimes
available to the driver)
struct Pt_reg *regs are very rarely used. It holds the processor context snapshot before the processor enters the interrupt code
The interrupt processing routine should return a value. Used to indicate whether an interrupt was actually handled. If the processing routine finds that its device does need to be processed, it should return irq_handled. Otherwise. The return value should be Irq_none
Ena
up
Linux device driver Development related content:
Armlinux working mode.SVC (Management) mode, USR mode;usr mode switches to svc mode. switching through software interrupts;When the code is running in USR mode, the software corresponds to the user space;When the code is running in SVC mode, the software runs in the kernel space.
User space and kernel space:User space:Included software: application (software), C library, its own encapsulation of the
Block device drivers for flash memory devices The first version of Windows CE was used solely on platforms with battery-backed Ram storage with a simple file system to manage the storage. however, Windows CE versions 2.10 and later are often used on embedded systems that require persistent storage and cannot depe
Precautions for developing Device Drivers in Visual C ++
To put it simply, the process of using the makefile project to create a device driver is to call the DDK command in Visual C ++. The execution sequence of the command window is the same as that of the DDK Command Prompt window, the executable files of the driver are also stored in the same directory. The di
Skb_release_data function has 0xc4 so large, and oops occurs at 0x74 place. So let's take a look at where the Skb_release_data starts:#grep Skb_release_data./system.mapC0282AF4 T Skb_release_dataSo we know that when the system error occurs, the program pointer is c0282af4+0x74=c0282b68(2) Then use GDB to view the GDB./vmlinux (executed under the Linux directory) and enter debug mode.gdb$ b *0xc0282b68Breakpoint 1 at 0xc0282b68:file NET/CORE/SKBUFF.C, line312This is to tell us in which file, in
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