Embedded Linux Conference & IoT summit 2016 first took place in the US in April, but the events are now also scheduled in Europe on October 11 – 13 in Berlin, Germany, and the schedule has now been published. Even if you are no going to attend, it’s always interesting to find out more about the topic covered in that type of events, so I had a look, and created my own virtual schedule with some of the sessions.
Configuring the rootfs to be read-only makes embedded systems more robust and reduces the wear on flash storage. In addition, by removing all state from the rootfs it becomes easier to implement system image updates and factory reset.
In this presentation, Chris shows how to identify components that need to store some state, and to split it into volatile state that is needed only until the device shuts down and non-volatile state that is required permanently. He gives examples and shows various techniques of mapping writes onto volatile or non-volatile storage. To show how this works in practice, he uses a standard Yocto Project build and shows what changes you have to make to achieve a real-world embedded system with read-only rootfs. In the last section, Chris considers the implications for software image update. Expect a live demonstration.
- 14:00 – 14:50 – Comparison of Linux Software Update Technologies – Matt Porter, Konsulko
The update of software in an embedded Linux system has always been an important part of any product. In the past, however, planning and design for software update was often an afterthought in system design. Further, software update mechanisms for embedded Linux products were typically implemented as ad hoc one-off projects within each product company. As the requirements for products have matured to include security updates at a frequent intervals, software update strategy has become a focal point of product development. This session will explore a number of different Linux software update technologies that are FOSS projects, comparing each for their strengths and weaknesses. In order to better understand the applicability of these technologies, we will also deep dive into both common and uncommon use cases that drive requirements for these software update mechanisms.
- 15:00 – 15:50 – Building a Micro HTTP Server for Embedded System – Jian-Hong Pan
Apache HTTP Server, NGINX .. are famous web servers in the world. More and more web server frameworks come and follow up, like Node.js, Bottle of Python .., etc. All of them make us have the abilities to get or connect to the resources behind the web server. However, considering the limitations and portability, they may not be ported directly to the embedded system which has restricted resources. Therefore, we need to re-implement an HTTP server to fulfill that requirement.
Jian-Hong will introduce how he used the convenience of Python to implement a Micro HTTP Server prototype according to RFC 2616/HTTP 1.1. Then, re-write the codes in C to build the Micro HTTP Server and do the automated testing with Python Unit Testing Framework. Finally, he’ll explain how he combined the Micro HTTP Server with an RTOS, and lit the LEDs on an STM32F4-Discovery board.
- 16:10 – 17:00 – Stuck in 2009 – How I Survived – Will Sheppard, Embedded Bits Limited
When developing Linux based products it’s desirable to use the latest version of the Linux kernel – however this is not always possible. In this presentation Will Sheppard will enlighten you with his experiences in developing a product based on a 2.6.28 kernel. Throughout the presentation he will share with you the reasons why you can be stuck with an old kernel, the issues this causes and the surprising and unexpected benefits that also arise. The presentation will also give you an indication as to how far the kernel has developed since 2009 and perhaps some hope if you too are also stuck working in the past.
- 17:10 – 18:00 – Power Management Challenges in IoT and How Zephyr RTOS Meets Them – Ramesh Thomas, Intel
An OS that runs on tiny IoT devices is already meeting several challenges. These challenges are due to the limited resources in these devices and the diverse nature of the applications and the ecosystem. These same reasons make adding an effective power management infrastructure extremely complex. These devices that run on tiny batteries for extensive periods, mostly unattended, have a very critical need to conserve power.
Zephyr is a RTOS from Intel, designed for IoT and wearable devices. It is open source and supports x86, ARM and ARC SoC platforms. It has a small footprint and can run with very less memory. Power management is built in the core of its scheduling and idling design. It exports infrastructure for PM services to implement custom power policies.
This presentation will give an insight into the Zephyr power management design and the philosophies behind it.
- 18:10 – 19:00 – BoF: Linux Device Performance Framework – Michael Turquette, BayLibre
Complex system-on-chip processors provide performance levels for their devices and peripherals. The same chips also provide interconnects with performance knobs connecting these devices. For years, Linux has not provided a way to express the relationship between a device and its performance states, nor a uniform method for drivers to change these states. There are many solutions to this in downstream vendor trees. Let’s fix that.
The purpose of this BoF is to start a discussion around the topic with a wide audience, solicit feedback on the currently proposed approach and move forward with consensus. This BoF will discuss the types of performance states that need to be modeled, existing Linux driver frameworks that can be re-used, new code that needs to be written and how Device Tree plays a role. Will we write a new DVFS or Interconnect Framework? Attend and find out!
- 09:00 – 09:50 – Supporting the Camera Interface on the C.H.I.P – Maxime Ripard, Free Electrons
Every modern multimedia-oriented ARM SoC usually has some kind of camera interface to be able to capture a video (or photo) stream from an external camera. The framework of choice to support these controllers in Linux is the Video4Linux subsystem, also called v4l2.
This talk will walk through the v4l2 stack, the architecture of a v4l2 driver and the interaction between the SoC driver and its camera’s. The presentation is based on the work Free Electrons has done to develop such a driver for the Allwinner SoCs, as part of enabling the C.H.I.P platform with the upstream Linux kernel.
- 10:00 – 10:50 – How to Develop the ARM 64bit Board, Samsung TM2 with Exynos5433 – Chanwoo Choi, Samsung Electronics
In the last period of twenty years ARM has been undisputed leader for processor’s architecture in the embedded and mobile industry. With its 64 bit platform, ARM widens up its field of applicability. The ARMv8 introduces a new register set, it is compatible with its 32 bit predecessor ARMv7 and suits best those system that try to be amongst the high end performance devices. Tizen OS is an open multi profile platform that can run on TV, mobile, cars and wearables. Samsung TM2 board based on Exynos5433, which patches has been recently posted to mainline, is an ARM 64-bit board supported by Tizen 64-bit. However, during the bring-up, the kernel developers have faced many challenges that will be presented in this session. The presentation will go through a number of issues and the way they have been solved in order to make Tizen run on a 64 bit platform.
- 10:45 – 11:35 – Devicetree Hardware Autoconfiguration – Hans de Goede, Red Hat
One can buy 7″ android tablets for around $35 now, assuming one gets the standard Q8 Allwinner based model, these are actually supported by the mainline linux kernel now. These tablets use a standard case + SoC + display, which get paired with a different touchscreen-controller, accelerometer and wifi chip for every other batch.
This talk will outline my experience in making a single devicetree file covering all variants using an in kernel hardware auto-detection module which creates and applies devicetree changesets depending on the detected hardware. This talk will give the audience an idea what is and is not possible wrt dynamic devicetree usage as well as give does and don’ts for people who want to use dynamic devicetree themselves.
- 11:45 – 12:35 – Wyliodrin STUDIO: An Open Source Tool for IoT Development – Alexandru Radovici, Wyliodrin
Have you been using your development board (like the Raspberry pi for example) as a glorified computer? Are you tired of needing to hookup your boards to a display and keyboard any time you want to program them?
Wyliodrin STUDIO is a software development tool especially created for the design of IoT projects. It comes as an open source Chrome extension so that programmers can use it independently of their specific OS platform and with little setup overhead.
Wyliodrin STUDIO abstract away many of the issues regarding setting up your development boards and allows programmers to directly focus on their projects. It offers a friendly programming environment with many of the features of advanced IDEs, like Eclipse. For beginners, Wyliodrin STUDIO offers a large range of tutorials to help people take their first steps in IoT development. MagPi gave Wylidorin STUDIO a 5/5 rating.
- 14:00 – 14:50 – ASoC: Supporting Audio on an Embedded Board – Alexandre Belloni, Free Electrons
ASoC, which stands for ALSA System on Chip, is a Linux kernel subsystem created to provide better ALSA support for system-on-chip and portable audio codecs. It allows to reuse codec drivers across multiple architectures and provides an API to integrate them with the SoC audio interface.
This talk will present the typical hardware architecture of audio devices on embedded platforms, present the ASoC API and how to use it for machine drivers, which are used to glue audio codecs with the processor audio interface. Examples, common issues and debugging tips will also be discussed.
- 15:00 – 15:50 – Cameras in Embedded Systems: Device Tree and ACPI View – Sakari Ailus, Intel
Cameras in embedded systems are often collections of different components rather than monolithic devices such as USB webcams. They consist of sensors, lenses, LED or xenon flashes and ISPs, each of which are individual devices with their specific drivers.
Once the prevalent solution for supporting hardware variation between different ARM based systems was platform data. Since around 2011 new platform data files have had hard time getting to mainline, the preferred solution being the Device tree. However, Device tree support in the V4L2 framework was not around until over a years after that, additionally help from the V4L2 async framework is also required in order to achieve the same functionality as with platform data.
This talk shows how the frameworks are used in drivers and Device tree source, reviews the status of ACPI and discuss potential future developments.
- 16:30 – 17:20 – Swapping and Embedded: Compression is the Key – Vitaly Wool
Ever since Linux started running on embedded devices, having a swap for such had been considered a misconfiguration rather than a method for overcoming RAM shortage or performance booster. This attitude started to change with the spread of Android devices which usually don’t have a problem utilizing virtually any amount of memory. An with the introduction of ZRAM the usage of a compressed swap in RAM became more useful and more popular. This talk will give a comprehensive description of ZRAM and its counterpart, zswap, a summary of pros and cons of both. This talk will also cover a brand new z3fold compressed memory allocator which can be used for both zswap and ZRAM, of course presenting measurement results for these, obtained on various devices, ranging from set top boxes to laptops, not to forget Android phones.
- 09:00 – 09:50 – Time is Ready for the Civil Infrastructure Platform – Yoshitake Kobayashi, Corporate Software Engineering Center & Urs Gleim, Seimens
The Civil Infrastructure Platform (CIP) – launched in April – CIP defined and started to realize a super long-term supported open source “base layer” for industrial grade software. This base layer aims to be used for current and future industrial systems which supports machine-to-machine connectivity for digital future. This kind of systems, being the field for decades, should have long-term support for security and robustness reasons. In this talk, we will show the first steps on CIP development. This includes initial set of components for the base layer and its maintainers. Are you ready? It’s time to start your development with and for the CIP.
- 10:00 – 10:50 – Introduction to Memory Management in Linux – Alan Ott, Signal 11 Software
All modern non-microcontroller CPUs contain a memory management unit and utilize the concept of virtual memory. This presentation will describe the different types of virtual memory spaces and mappings used in the Linux kernel, the cases in which they are useful, how they are implemented in the kernel, and how they differ from user space memory. Concepts such as the hardware memory-management unit (MMU) and translation lookaside buffer (TLB) will be discussed, as well as software concepts like kernel page tables. User space concepts such as growable stacks, memory paging, memory mapping, page faults, exceptions, and other memory-related conditions will be covered as well.
With the introduction of the Zephyr Project, a small scalable real-time operating system for use on resource-constrained systems, the need for an easy to use platforms to enable Internet of Things development has grown. With the idea of enabling both hardware and software developers to quickly prototype and develop proof-of-concept, as well as transitioning directly to product, the MinnowBoard Delta was designed as an open source hardware platform to highlight the Zephyr Project. This presentation will cover design considerations as well as implementation methods for creating open source hardware specifically for open source software.
- 12:15 – 13:05 – Cloud Platforms for the Internet of Things: How Do They Stack Up? – Koustabh Dolui, Politecnico di Milano
With the advent of the Internet of Things (IoT), there has been a recent surge in the number of cloud platforms offering their services for data collection and processing from IoT devices. These platforms, open-source and closed, are diverse in terms of ease of use, architecture, data storage, privacy, security and communication protocols. However, how these cloud platforms measure up against each other, given the set of tradeoffs that they present, remains quite unexplored in existing literature. In this presentation, Koustabh will present a detailed study on the architecture that these platforms are based on and how the open source platforms compare against closed platforms. Koustabh will compare the platforms based on a real data-set generated from a sensor network deployed at the heritage site of Circo Massimo, Rome, as a part of an ongoing project at Politecnico di Milano, Italy.
- 14:30 – 15:20 – GPIO for Engineers and Makers – Linus Walleij
- 15:30 – 16:20 – FDO: Magic ‘Make My Program Faster’ Compilation Option? – Pawel Moll, ARM
Feedback Driven Optimisation (FDO), also known as Profile Guided Optimisation (PGO) is a well known code optimisation technique, employed by compilers since mid XX century, yet not widely used in the wild these days. It relies on providing runtime-captured information about code execution (eg. “branch taken or not?”) during next code compilation, improving quality of decisions made by compiler heuristics.
To be fair, there were good reasons for its demise which I hope to discuss, mainly time and complexity overhead and deployment difficulties, but there is some hope on the horizon, coming with new approach, called AutoFDO and originating at Google, based on statistical profiling (namely Linux perf + extra tools) and source code level attribution. I’ll discuss existing support for it available in mainline GCC and LLVM and give examples of real-life, successful deployments.
If you’d like to attend the event, you can do so by registering online, and paying the entry fee:
Early Registration Fee: US$550 (through August 1, 2016)
- Standard Registration Fee: US$650 (August 2, 2016 – September 3, 2016)
- Late Registration Fee: US$850 (September 4, 2016 – Event)
- Student Registration Fee: US$175 (valid student ID required)
- Hobbyist Registration Fee: US$175