Problem Statement
Create a simple device driver (character device) for the compiled kernel (in Assignment-1) and test it with a sample application.
EXECUTION OF CHARACTER DEVICE DRIVER
1) assgn2_simple_char_drv.c
This C file contains the code of a CHARACTER DEVICE DRIVER.
Character device drivers normally perform I/O in a byte stream. Examples of devices using character drivers include tape
drives and serial ports. Character device drivers can also provide additional interfaces not present in block drivers,
such as I/O control (ioctl) commands, memory mapping, and device polling.
MAKEFILE
1) Makefile
This is the makefile for our character device driver. This is responsible for building objects, it is our present working
directory. Our main objective is to make a kbuild makefile so our makefile code contain a single line command i.e
obj -m := ex07_simple_char_drv.o
all:
make -C /lib/modules/$(uname -r)/build M=$PWD modules
clean:
make -C /lib/modules/$(uname -r)/build M=$PWD clean
This tells there is a object in the directory named ebbchar.o and obj-m tells that this object should be built as a
module
COMMANDS THAT ARE FOLLOWED
-
Makesure that the terminal is in the correct directory where the source code and makefile are present.
-
To compile the modules of driver run
make -
To insert our compiled module to the kernel run
sudo insmod assgn2_simple_char_drv.ko -
To verify wheteher module inserted or not run
lsmod |grep assgn2 -
To show list of character devices and block devices run
cat /proc/devices -
To make the device accessible run
sudo mknod -m 666 /dev/simple_char_device c 240 0 -
To verify whether char_device is available for the given node run
ls -l /dev/simple_char_device -
To show the system log console run
sudo tail -f /var/log/syslog