The Embedded Linux Conference & IoT summit 2017 took place in the US earlier this year in February, but there will soon be a similar event with the Embedded Linux Conference *& Open Source Summit Europe 2017 to take up in Europe on October 23 – 25 in Prague, Czech Republic, and the Linux Foundation has just published the schedule. It’s always useful to find out what is being discussed during such events, even if you are not going to attend, so I went through the different sessions, and compose my own virtual schedule with some of the ones I find the most interesting.

Monday, October 23

11:15 – 11:55 – An Introduction to SPI-NOR Subsystem – Vignesh Raghavendra, Texas Instruments India Modern day embedded systems have dedicated SPI controllers to support NOR flashes. They have many hardware level features to increase the ease and efficiency of accessing SPI NOR flashes and also support different SPI bus widths and speeds. In order to support such advanced SPI NOR controllers, SPI-NOR framework was introduced under Memory Technology Devices (MTD). This presentation aims at providing an overview of SPI-NOR framework, different types of NOR flashes supported (like SPI/QSPI/OSPI) and interaction with SPI framework. It also provides an overview of how to write a new controller driver or add support for a new flash device. The presentation then covers generic improvements done and proposed while working on improving QSPI performance on a TI SoC, challenges associated when using DMA with these controllers and other limitations of the framework. The open source hardware movement is becoming more and more popular. But is it worth making open source hardware if it has been designed with expensive proprietary software? In this presentation, Leon Anavi will share his experience how to use free and open source software for making high-quality entirely open source devices: from the designing the PCB with KiCAD through making a case with OpenSCAD or FreeCAD to slicing with Cura and 3D printing. The talk will also provide information about open source hardware licenses, getting started guidelines, tips for avoiding common pitfalls and mistakes. The challenges of prototyping and low-volume manufacturing with both SMT and THT will be also discussed. In this talk, Marek introduces the increasingly popular single-chip SoC+FPGA solutions. At the beginning, the diverse chip offerings from multiple vendors are introduced, ranging from the smallest IoT-grade solutions all the way to large industrial-level chips with focus on their software support. Mainline U-Boot and Linux support for such chips is quite complete, and already deployed in production. Marek demonstrates how to load and operate the FPGA part in both U-Boot and Linux, which recently gained FPGA manager support. Yet to fully leverage the potential of the FPGA manager in combination with Device Tree (DT) Overlays, patches are still needed. Marek explains how the FPGA manager and the DT Overlays work, how they fit together and how to use them to obtain a great experience on SoC+FPGA, while pointing out various pitfalls. 15:10 – 15:50 – Cheap Complex Cameras – Pavel Machek, DENX Software Engineering GmbH

Cameras in phones are different from webcams: their main purpose is to take high-resolution still pictures. Running preview in high resolution is not feasible, so resolution switch is needed just before taking final picture. There are currently no applications for still photography that work with mainline kernel. (Pavel is working on… two, but both have some limitations). libv4l2 is doing internal processing in 8-bit, which is not enough for digital photography. Cell phones have 10 to 12-bit sensors, some DSLRs do 14-bit depth.

Differences do not end here. Cell phone camera can produce reasonable picture, but it needs complex software support. Auto-exposure / auto-gain is a must for producing anything but completely black or completely white frames. Users expect auto-focus, and it is necessary for reasonable pictures in macro range, requiring real-time processing.

16:20 – 17:00 – Bluetooth Mesh with Zephyr OS and Linux – Johan Hedberg, Open Source Technology Center, Intel

Bluetooth Mesh is a new standard that opens a whole new wave of low-power wireless use cases. It extends the range of communication from a single peer-to-peer connection to a true mesh topology covering large areas, such as an entire building. This paves the way for both home and industrial automation applications. Typical home scenarios include things like controlling the lights in your apartment or adjusting the thermostat. Although Bluetooth 5 was released end of last year, Bluetooth Mesh can be implemented on any device supporting Bluetooth 4.0 or later. This means that we’ll likely see very rapid market adoption of the feature.

The presentation will give an introduction to Bluetooth Mesh, covering how it works and what kind of features it provides. The talk will also give an overview of Bluetooth Mesh support in Zephyr OS and Linux and how to create wireless solutions with them.

17:10 – 17:50 – printk() – The Most Useful Tool is Now Showing its Age – Steven Rostedt, VMware

printk() has been the tool for debugging the Linux kernel and for being the display mechanism for Linux as long as Linux has been around. It’s the first thing one sees as the life of the kernel begins, from the kernel banner and the last message at shutdown. It’s critical as people take pictures of a kernel oops to send to the kernel developers to fix a bug, or to display on social media when that oops happens on the monitor on the back of an airplane seat in front of you.

But printk() is not a trivial utility. It serves many functionalities and some of them can be conflicting. Today with Linux running on machines with hundreds of CPUs, printk() can actually be the cause of live locks. This talk will discuss all the issues that printk() has today, and some of the possible solutions that may be discussed at Kernel Summit.

18:00 – 18:45 – BoF: Embedded Linux Size – Michael Opdenacker, Free Electrons

This “Birds of a Feather” session will start by a quick update on available resources and recent efforts to reduce the size of the Linux kernel and the filesystem it uses.

An ARM based system running the mainline kernel with about 3 MB of RAM will also be demonstrated. If you are interested in the size topic, please join this BoF and share your experience, the resources you have found and your ideas for further size reduction techniques!

Tuesday, October 24

Continuous Integration (CI) has been a hot topic for long time. With the growing number of architectures and boards, it becomes impossible for maintainers to validate a patch on all configurations, making it harder and harder to keep the same quality level without leveraging CI and test automation. Recent initiatives like LAVA, KernelCI.org, Fuego, (…) started providing a first answer, however the learning curve remains high, and the HW setup part is not covered.

Baylibre, already involved in KernelCI.org, decided, as part of the AGL project, to go one step further in CI automation and has developed a turnkey solution for developers and companies willing to instantiate a LAVA lab; called “Lab in a Box”, it aims at simplifying the configuration of a board farm (HW, SW).

Motivations, challenges, benefits and results will be discussed, with a demo of a first “Lab in a Box” instantiation.

11:45 – 12:25 – Protecting Your System from the Scum of the Universe – Gilad Ben-Yossef, Arm Holdings

Linux based systems have a plethora of security related mechanisms: DM-Crypt, DM-Verity, Secure Boot, the new TEE sub-system, FScrypt and IMA are just a few examples. This talk will describe these the various systems and provide a practical walk through of how to mix and match these mechanisms and design them into a Linux based embedded system in order to strengthen the system resilience to various nefarious attacks, whether the system discussed is a mobile phone, a tablet, a network attached DVR, a router, or an IOT hub in a way that makes maximum use of the sometime limited hardware resources of such systems.

Neuroimaging is an established medical field which is helping us to learn more about how the human brain works, the most complex human organ. This talk aims to cover neuroimaging systems, from hobbyist to professional, and how open source has been used to build state-of-the-art systems. We’ll have a look the general problem area, why open source was a good fit, and some examples of solutions including a commercial effort that we have been involved in bringing to market. Typically these solutions consist of specialist hardware, a bespoke software solutions stack, and a suite to manage and process the vast amounts of data generated during the scan. Other points of interest include how we approached building a maintainable and upgradeable system from the outset. We’ll also talk about future plans for neuroimaging, future ideas for hardware & discuss areas lacking good open source solutions. It has its challenges to write code for certain error paths for I2C bus drivers because these errors usually don’t happen on the bus. And special I2C bus testers are expensive. In this talk, a new GPIO based driver will be presented which acts on the same bus as the bus master driver under inspection. A live demonstration will be given as well as hints how to handle bugs which might have been found. The scope and limitations of this driver will be discussed. Since it will also be analyzed what actually happens on the wires, this talk also serves as a case study how to snoop busses with only Free Software and OpenHardware (i.e. sigrok). GStreamer is a complete Open Source multimedia framework, and it includes hundreds of plugins, including modern formats like DASH, HLS or the first ever RTSP 2.0 implementation. The whole framework is almost 150MB on my computer, but what if you only have 5 megs of flash available? Is it a viable choice? Yes it is, and I will show you how. Starting with simple tricks like only including the necessary plugins, all the way to statically compiling only the functions that are actually used to produce the smaller possible footprint. Industrial grade solutions have a life expectancy of 30+ years. Maintaining a Linux kernel for such a long time in the open has not been done. Many claim that is not sustainable, but corporations that build power plants, railway systems, etc. are willing to tackle this challenge. This talk will describe the work done so far on the kernel maintenance and testing front at the CIP initiative. During the talk it will be explained how we decide which parts of the kernel to cover – reducing the amount of work to be done and the risk of being unable to maintain the claimed support. The process of reviewing and backporting fixes that might be needed on an older branch will be briefly described. CIP is taking a different approach from many other projects when it comes to testing the kernel. The talk will go over it as well as the coming steps. and the future steps. Wednesday, October 24 So you want to support HDMI 4k (3840×2160) video output and/or video capture for your new product? Then this is the presentation for you! I will describe the challenges involved in 4k video from the hardware level, the HDMI protocol level and up to the kernel driver level. Special attention will be given to what to watch out for when buying 4k capable equipment and accessories such as cables and adapters since it is a Wild, Wild West out there. In my talk/presentation, I cover the technical, and design challenges in developing an autonomous Linux powered Arctic buoy. This system is a low cost, COTS based, extreme/harsh environment, autonomous sensor data gathering platform. It measures albedo, weather, water temperature and other parameters. It runs on a custom embedded Linux and is optimized for efficient use of solar & battery power. It uses a variety of low cost, high accuracy/precision sensors and satellite/terrestrial wireless communications. I talk about using Linux in this embedded environment, and how I address and solve various issues including building a custom kernel, Linux drivers, frame grabbing issues and results from cameras, limited power challenges, clock drifts due to low temperature, summer melt challenges, failure of sensors, intermittent communication issues and various other h/w & s/w challenges. 14:15 – 14:55 – Linux Storage System Bottleneck for eMMC/UFS – Bean Huo & Zoltan Szubbocsev, Micron The storage device is considered a bottleneck to the system I/O performance. This thinking drives the need for faster storage device interfaces. Commonly used flash based storage interfaces support high throughputs, eg. eMMC 400MB/s, UFS 1GB/s. Traditionally, advanced embedded systems were focusing on CPU and memory speeds and these outpaced advances in storage speed improvements. In this presentation, we explore the parameters that impact I/O performance. We describe at a high level how Linux manages I/O requests coming from user space. Specifically, we look into system performance limitations in the Linux eMMC/UFS subsystem and expose bottlenecks caused by the software through Ftrace. We show existing challenges in getting maximum performance of flash-based high-speed storage device. by this presentation, we want to motivate future optimization work on the existing storage stack. Since Linux 4.8 the GPIO sysfs interface is deprecated. Due to its many drawbacks and bad design decisions a new user space interface has been implemented in the form of the GPIO character device which is now the preferred method of interaction with GPIOs which can’t otherwise be serviced by a kernel driver. The character device brings in many new interesting features such as: polling for line events, finding GPIO chips and lines by name, changing & reading the values of multiple lines with a single ioctl (one context switch) and many more. In this presentation, Bartosz will showcase the new features of the GPIO UAPI, discuss the current state of libgpiod (user space tools for using the character device) and tell you why it’s beneficial to switch to the new interface. With the WikiLeaks release of the vault7 material, the security of the UEFI (Unified Extensible Firmware Interface) firmware used in most PCs and laptops is once again a concern. UEFI is a proprietary and closed-source operating system, with a codebase almost as large as the Linux kernel, that runs when the system is powered on and continues to run after it boots the OS (hence its designation as a “Ring -2 hypervisor”). It is a great place to hide exploits since it never stops running, and these exploits are undetectable by kernels and programs. Our answer to this is NERF (Non-Extensible Reduced Firmware), an open source software system developed at Google to replace almost all of UEFI firmware with a tiny Linux kernel and initramfs. The initramfs file system contains an init and command line utilities from the u-root project, which are written in the Go language. Unikernel is a novel software technology that links an application with OS in the form of a library and packages them into a specialized image that facilitates direct deployment on a hypervisor. But why these existing unikernels have yet to gain large popularity broadly? I’ll talk what challenges Unikernels are facing, and discuss exploration of if-how we could convert Linux as Unikernel, and IoT could be a valuable one of use cases because the feature of smaller size & footprint are good for those resource-strained IoT platforms. Those existing unikernels are not designed to address those IoT characters like power consumption and real time requirement, and they also doesn’t support versatile architectures. Most existing Unikernels just focus on X86/ARM. As a paravirtualized unikenelized Linux, especially Unikernelized Real Time Linux, really makes Unikernels to succeed. If you’d like to attend the real thing, you’ll need to register and pay a registration fee: Early Registration Fee: US$800 (through August 27, 2017)

US$800 (through August 27, 2017) Standard Registration Fee: US$950 (August 28, 2017 – September 17, 2017)

US$950 (August 28, 2017 – September 17, 2017) Late Registration Fee: US$1100 (September 18, 2017 – Event)

US$1100 (September 18, 2017 – Event) Academic Registration Fee: US$200 (Student/Faculty attendees will be required to show a valid student/faculty ID at registration.)

US$200 (Student/Faculty attendees will be required to show a valid student/faculty ID at registration.) Hobbyist Registration Fee: US$200 (only if you are paying for yourself to attend this event and are currently active in the community) There’s also another option with the Hall Pass Registration ($150) if you just want to network on visit with sponsors onsite, but do not plan to attend any sessions or keynotes.