Linux device driver
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This document discusses Linux device drivers. It provides an overview of the history and purpose of Linux and device drivers. It explains that device drivers connect hardware and software by communicating at both the logical and physical layers. It also describes the difference between kernel and user modes, and discusses how device drivers are developed by utilizing Linux system calls and supporting development environments within the Linux kernel programming interface.
![Device Driver Programming
% make
#include <linux/init.h>
#include <linux/module.h> make[1]: Entering directory `/usr/src/linux-2.6.10'
MODULE_LICENSE("Dual BSD/GPL"); CC [M] /home/ldd3/src/misc-modules/hello.o
Building modules, stage 2.
static int hello_init(void) MODPOST
{ CC
printk(KERN_ALERT "Hello, worldn");
/home/ldd3/src/misc-modules/hello.mod.o
return 0;
LD [M] /home/ldd3/src/misc-modules/hello.ko
}
make[1]: Leaving directory `/usr/src/linux-2.6.10'
static void hello_exit(void) % su
{ root# insmod ./hello.ko
printk(KERN_ALERT "Goodbye, cruel worldn"); Hello, world
} root# rmmod hello
Goodbye cruel world
module_init(hello_init);
root#
module_exit(hello_exit);
Linux kernel in a nutshell,3rd-Greg Kroah-Hartman](https://image.slidesharecdn.com/linuxdevicedriver-111029203017-phpapp01/85/Linux-device-driver-10-320.jpg)
Linux device driver
- 2. Agenda History & Why Linux kernel? Device Driver. Purpose & Design Kernel mode & User mode Development Application & API
- 3. History and Why Linux kernel? First developed by Linus Torvals. Linux base on UNIX standard. Workgroup for implement driver & patch with kernel.org. ”Just for fun” - Linux Torvals History.
- 4. Pupose & Design Connection between Hardware and Software. Design communicate on logical layer ( Port : ttyS,lp,hd) and physical layer(Handle stardard of communication protocol). Linux kernel (.ko file type) & Microsoft (.sys file type ) kernel( Monolithic,Micro,Hybird )
- 5. Linux boot sequence on x86 x86 Real Mode BIOS Bootloader ( GRUB/LILO ) Real Mode Kernel X86 Protected Arch/x86/boot/pm.c Mode Protected Mode kernel The init Process User Processes and Daemons Booting up,Essential Linux Device Drivers-Venkateswaran.
- 6. User & Kernel mode. Kernel Mode It can execute any CPU instruction and reference any memory address. Kernel mode is generally reserved for the lowest-level”. Most, ”trusted functions of the operating system”. User Mode In User mode, the executing code has no ability to directly access hardware or reference memory. Code running in user mode must delegate to system APIs to access hardware or memory. Understanding user & kernel mode,Coding Horror-Jeff Atwood
- 7. Development Linux System Call. Device Drivers Development Supporting device drivers. Kernel Programming Environment.
- 8. Linux System Call Executing in kernel mode. Kernel mode recognize and particular action is require from the device. Call to device routine which pass user process to device routine. Device routine may be shared simulataneously by user application
- 9. Device Drivers Development Supporting device drivers. A set of routines that communicate with a hardware device and provide a uniform interface to the operating system kernel. A self-contained component that can be added to, or removed from, the operating system dynamically. Management of data flow and c ontrol between user programs and a peripheral device. A user-defined section of the kernel that allows a program or a peripheral device to appear as a `` /dev '' device to the rest of the system's software. Write a Linux Hardware Device Driver.FreeSoftware Mag.
- 10. Device Driver Programming % make #include <linux/init.h> #include <linux/module.h> make[1]: Entering directory `/usr/src/linux-2.6.10' MODULE_LICENSE("Dual BSD/GPL"); CC [M] /home/ldd3/src/misc-modules/hello.o Building modules, stage 2. static int hello_init(void) MODPOST { CC printk(KERN_ALERT "Hello, worldn"); /home/ldd3/src/misc-modules/hello.mod.o return 0; LD [M] /home/ldd3/src/misc-modules/hello.ko } make[1]: Leaving directory `/usr/src/linux-2.6.10' static void hello_exit(void) % su { root# insmod ./hello.ko printk(KERN_ALERT "Goodbye, cruel worldn"); Hello, world } root# rmmod hello Goodbye cruel world module_init(hello_init); root# module_exit(hello_exit); Linux kernel in a nutshell,3rd-Greg Kroah-Hartman