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D3Linux Drivers Writing Linux Drivers
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Objectives
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- This course is for engineers that install Linux on a custom platform and have to create specific device drivers.
- Theoretical course
- PDF course material (in English) supplemented by a printed version.
- The trainer answers trainees' questions during the training and provide technical and pedagogical assistance.
- Practical activities
- Practical activities represent from 40% to 50% of course duration.
- Code examples, exercises and solutions
- One PC (Linux ou Windows) for the practical activities with, if appropriate, a target board.
- One PC for two trainees when there are more than 6 trainees.
- For onsite trainings:
- An installation and test manual is provided to allow preinstallation of the needed software.
- The trainer come with target boards if needed during the practical activities (and bring them back at the end of the course).
- Downloadable preconfigured virtual machine for post-course practical activities
- At the start of each session the trainer will interact with the trainees to ensure the course fits their expectations and correct if needed
- Good C programming skills
- Preferably knowledge of Linux user programming (see our D0 - Linux user mode programming course or oD0 - Linux User Mode Programming course)
- The prerequisites indicated above are assessed before the training by the technical supervision of the traineein his company, or by the trainee himself in the exceptional case of an individual trainee.
- Trainee progress is assessed in two different ways, depending on the course:
- For courses lending themselves to practical exercises, the results of the exercises are checked by the trainer while, if necessary, helping trainees to carry them out by providing additional details.
- Quizzes are offered at the end of sections that do not include practical exercises to verifythat the trainees have assimilated the points presented
- At the end of the training, each trainee receives a certificate attesting that they have successfully completed the course.
- In the event of a problem, discovered during the course, due to a lack of prerequisites by the trainee a different or additional training is offered to them, generally to reinforce their prerequisites,in agreement with their company manager if applicable.
Course Outline
- Development in the Linux kernel
- Memory allocation
- Linked lists
| Exercise: | Writing the "hello world" kernel module | |
| Exercise: | Adding a driver to kernel sources and configuration menu | |
| Exercise: | Using module parameters | |
| Exercise: | Writing interdependent modules using memory allocations, reference counting and linked lists | |
- The /proc and debugfs filesystems
- Traces
- The kernel Dynamic Debugging interface
- The Kernel Address Sanitizer
- Debugging memory problems with kmemleak
- Using the Undefined Behavior Sanitizer
- Code coverage using gcov
- Debugging with kgdb
- Debugging with a JTAG probe
| Exercise: | Display dynamic traces on the running kernel | |
| Exercise: | Debug a module initialization using kgdb | |
- Task handling
- Concurrent programming
- Timers
- Kernel threads
| Exercise: | Fixing race conditions in the previous lab with mutexes | |
- Accessing the device driver from user space
- Driver registration
| Exercise: | Step by step implementation of a character driver: | |
| • | driver registration (major/minor reservation) and device special file creation (/dev) | |
- Kernel structures used by drivers
- Opening and closing devices
- Data transfers
- Controlling the device
- Mapping device memory
| Exercise: | Step by step implementation of a character driver: | |
| • | Implementing open and release | |
| • | Implementing read and write | |
| • | Implementing ioctl | |
| • | Implementing mmap | |
- Task synchronization
- Synchronous request
- Asynchronous requests
| Exercise: | implementation of a pipe-like driver: | |
| • | implementing waiting and waking | |
| • | adding non-blocking, asynchronous and multiplexed operations (O_NONBLOCK, SIGIO, poll/select) | |
- Memory-mapped registers
- Interrupts
- Gpios
- User-level access through /sys or the GPIO character driver
| Exercise: | Polling gpio driver with raw register access | |
| Exercise: | Interrupt-based gpio driver with raw register access | |
| Exercise: | gpio driver using the gpiolib | |
- Plug-and-Play management
- Static devices declaration
- in the BSP code
- in the device tree
- Platform bus
- PCI
- SPI
- Power management
- System sleep
- Implementing power management in drivers
- Remote wakeup
| Exercise: | Implementing a platform driver and customizing the device tree to associate it to its device (a serial port) | |
| Exercise: | Implementing power management in the previous driver | |
| Exercise: | Implementing remote wakeup in the previous driver | |
- Linux Driver Model Architecture
- Overview
- Classes
- Busses
- Hot plug management
- Plugging devices
- Removing devices
- Writing udev rules
| Exercise: | Writing a custom class driver | |
| Exercise: | Writing a misc driver | |
- Direct Memory Access
- DMA scenarios
- Buffer access
- DMA programming
- Bus master DMA
- Slave DMA
- Memory barriers
| Exercise: | Implementing slave DMA in a serial port driver | |
- The USB bus
- USB devices
- User-space USB interface
- USB descriptors
- USB requests
- USB device drivers
| Exercise: | Writing a USB host driver | |
- structures
- network interface representation (struct net_device)
- network packet (struct sk_buff)
- scatter/gather
- interface
- receiving packets
- sending packets
- lost packets management
- network interface statistics
- New network API (NAPI)
- "interrupt mitigation" (suppression of unneeded IRQs)
- "packet throttling" (suppression of packets in the driver itself when system is overwhelmed)
- Virtual Memory
- Memory Allocation
- Free page management
- Normal memory allocation
- Virtual memory allocation
- Huge allocations
More
To book a training session or for more information, please contact us on info@ac6-training.com.
Registrations are accepted till one week before the start date for scheduled classes. For late registrations, please consult us.
You can also fill and send us the registration form
This course can be provided either remotely, in our Paris training center or worldwide on your premises.
Scheduled classes are confirmed as soon as there is two confirmed bookings. Bookings are accepted until 1 week before the course start.
Last update of course schedule: 15 November 2022
Booking one of our trainings is subject to our General Terms of Sales