CIMWare - Principal Engineer _CTO's Office

Company - CIMWare 

Principal Engineer – CTO's Office

Work Mode- 5 Days Onsite

Introduction :- 
CIMware is an equal job opportunity employer and looking forward to having team of 4 engineers for
CTO's office, reporting directly to CTO.

A Linux PCIe (Peripheral Component Interconnect Express) device driver developer occupies a
crucial role in the creation and maintenance of hardware interface software, enabling a wide variety
of PCIe devices — such as network cards, storage controllers, graphics adapters and custom
hardware accelerators — to function seamlessly with the Linux operating system. Developing drivers
for PCIe devices, a keen understanding of kernel subsystems and a disciplined approach to software
engineering. This document outlines the typical requirements, competencies, and expectations for a
professional specializing in this domain.
Core Technical Skills
Linux Kernel Programming
● Deep Understanding of Linux Kernel Architecture: Familiarity with kernel space versus user
space, kernel modules, device driver concepts, and memory management.
● Kernel Module Development: Experience writing loadable kernel modules (LKMs) and
integrating them with the Linux build system.
● Debugging and Profiling: Proficiency with debugging tools such as kgdb, ftrace, perf, dmesg,
and sysfs interfaces to troubleshoot and optimize drivers.
C/C++ Programming
● Expertise in C Language: Mastery of C for low-level, performance-sensitive code, including
bitwise operations, memory management, pointer arithmetic, and data structure optimization.
● Familiarity with C++: Advantageous for certain projects, though most Linux kernel drivers are
written in C. Understanding object-oriented concepts in a C context is also helpful.
PCIe Protocol and Hardware Knowledge
● Comprehensive Understanding of PCIe Specification: Knowledge of the PCIe standard,
including enumeration, configuration space, BARs (Base Address Registers), MSI/MSI-X
interrupts, and bus mastering.
● Device Datasheet Interpretation: Ability to read and interpret PCIe device hardware
documentation, including register maps, timing requirements, and signaling protocols.
● Interfacing with Firmware/BIOS: Understanding how PCIe devices are initialized during
system boot, and the mechanisms by which firmware and BIOS communicate with hardware.

Device Driver Development Lifecycle
● Probing and Initialization: Experience writing probe() and remove() functions to handle device
enumeration and teardown.
● Resource Management: Skills in managing memory and hardware resources, including DMA
(Direct Memory Access), I/O regions, and interrupt lines.
● Interrupt Handling: Ability to write efficient and robust interrupt handlers, using mechanisms
such as bottom halves, tasklets, work queues, and threaded interrupts.
● Power Management: Familiarity with runtime and system power management interfaces,
including suspend/resume operations.
● Concurrency and Synchronization: Understanding race conditions, atomic operations,
spinlocks, mutexes, and semaphores in a preemptible kernel environment.
Required Experience and Education
● Bachelor's or Master's Degree: In Computer Science, Electrical or Computer Engineering, or
a related technical field.
● Professional Experience: 15+ years of experience with Linux device driver development,
preferably with a focus on PCIe devices.

● Open Source Contribution: Experience contributing to the Linux kernel or relevant open-
source projects is highly valued.

Familiarity with Linux Driver Subsystems

● Character and Block Device Drivers: Understanding the differences and appropriate use-
cases for each device class.

● Sysfs and Procfs Interfaces: Skills in exposing driver parameters and status to user space,
and handling configuration via these interfaces.
● Networking, Storage, and Graphics Stacks: Knowledge of subsystem-specific APIs when
developing drivers for devices in these categories.
Development Tools and Environment
● Cross-Compilation and Toolchains: Familiarity with building for different hardware
architectures (x86, ARM, PowerPC, etc).
● Version Control: Proficiency with git and collaborative workflows such as pull requests and
code reviews.
● Continuous Integration: Experience with automated build and test systems, static analysis,
and quality assurance for kernel code.
● Emulators and Hardware Debuggers: Working knowledge of QEMU, JTAG, and other
hardware-in-the-loop debugging tools.
● Testing and Validation: Skills in writing and executing test cases, using tools like KUnit, LTP,
or custom user space utilities for driver validation.

Soft Skills and Professional Qualities
● Analytical Thinking: Ability to decompose complex problems and design robust, maintainable
solutions.
● Attention to Detail: Careful and methodical approach to low-level programming, where small
mistakes can have significant consequences.
● Collaboration: Strong communication skills for working with hardware teams, QA, and other
software engineers.
● Documentation: Ability to write clear, comprehensive documentation for driver interfaces,
installation, and troubleshooting.
● Adaptability: Willingness to learn new technologies, adapt to evolving kernel APIs, and
respond to feedback from code reviews and the open-source community.
Security and Reliability Considerations
● Secure Coding Practices: Understanding common vulnerabilities in kernel code, such as
buffer overflows, race conditions, and privilege escalation risks.
● Robust Error Handling: Ensuring drivers handle hardware faults, invalid inputs, and
unexpected states gracefully, without compromising system stability.
● Compliance: Awareness of licensing and intellectual property guidelines for kernel code,
especially when integrating proprietary firmware or hardware components.
Desirable Additional Qualifications
● Knowledge of Other Operating Systems: Familiarity with Windows, FreeBSD or RTOS driver
models for cross-platform development.
● Experience with FPGA, SoC, or Custom Hardware: Useful for teams working on nonstandard
PCIe endpoints or accelerators.
● Performance Tuning: Skills in profiling and optimizing for low-latency, high-throughput data
paths.
● Community Engagement: Involvement in Linux kernel mailing lists, conferences (such as
Linux Plumbers Conference), or speaking at industry events.
Job Description of a Principal Engineer
● Design, implement, and maintain PCIe device drivers for the
Linux kernel.
● Collaborate with hardware engineers to define device requirements and troubleshoot issues.
● Optimize driver performance for reliability, low latency, and high throughput.
● Write and maintain technical documentation for driver software and APIs.
● Participate in code reviews, testing, and release processes.
● Contribute to upstream Linux kernel or open-source projects as needed.

Conclusion
A Principal Engineer must master both the art and science of low-level software engineering,
combining a deep technical understanding of hardware and kernel architectures with the discipline to write maintainable, robust, and secure code.