Working of character driver :see diagram & also see some queries of character driver.
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The above diagram show how the character driver works in linux , user space to kernel space .
but when we implementing the driver there are many issues are find from inserting a driver to Removing the driver.
some are following:
why we use use sculldev because only cdev work as device of application ?
why we use container_of function if it,s only use of access the cdev address then what is its internal operations and how it work ?
we use kmalloc for providing the memory to sculldev if we want to print the value of sculldev which is garbage then that show errors : the variable is struct sculldev but we print value with %c ,there have no effect if we use type casting , what is solution ?
we use memset for fill the null values in sculldev how we can check sculldev filled with null ?
In cleanup function we use kfree ,that means free the memory of sculldev ,how we can check memory is totally free ,i mean how we can see that ?
The return type of unregister_chrdev_region is void ,if we want check our device is unregistered sucessfully using printk statement.
what is motive of using cdev_del function because we already use rmmod,unregister function and after that cdev_del function ,what main purpose of this function ,we can see the output of this function.
what fundamentals of struct file and why we make the struct file_operations because that is already included in header file which is fs.h and cdev.h .
Cdev is used for attachment of kernel to driver as an interface so that driver module may run with running module while sculldev will act as a virtual device....in which we perform write or read..
