Paul Kocialkowski

This talk will present how support for an advanced camera use case was integrated into the mainline Linux kernel, using the Media and V4L2 APIs. It involves supporting a sensor using the raw Bayer RGB format, transmission over the MIPI CSI-2 bus as well as support for the Image Signal Processor (ISP) found on Allwinner platforms. A specific focus will be set on this ISP, with details about the features it implements as well as the internal and userspace APIs that are used to support it.

Capturing pixels with a camera involves a number of steps, from the ADC reading the photosites in the image sensor to the final pixel values that are ready for encode/display, with various processing and transmission taking place along the way.

While simple cases put most of the heavy lifting on the image sensor's side (through its embedded processor) and use a simple parallel bus for transmission, advanced cases require more work to be done outside of the sensor. In addition, modern high-speed transmission buses also bring-in more complexity.

Si de nombreux logiciels libres sont développés pour prendre en charge le processeur principal de nos appareils numériques (en particulier au niveau du système et dans une moindre mesure du démarrage), de nombreux autres composants sont laissés pour compte. Une multitude de micro-contrôleurs restent en effet sous le joug de logiciels propriétaires, sans alternatives libres. Si ces composants sont moins visibles, ils sont bien souvent cruciaux pour la liberté, la vie privée et la sécurité. Le projet Origami-EC s'intéresse aux Embedded Controllers, qui assurent de nombreux aspects liés à la gestion d'énergie et aux entrées/sorties des ordinateurs portables. Le développement d'un logiciel libre pour ces composants sera présenté, avec tous les challenges et les contraintes techniques qui lui sont associés.

This workshop will be focused on Origami-Paper, with the intent of both assisting users of the project and adding support for more devices that can run with free boot software such as coreboot and U-Boot. In particular, we are aiming at integrating support for the Intel-based laptops supported by coreboot that can boot without proprietary blobs.

Nowadays, a significant number of devices are supported by free software projects related to hardware support, such as coreboot, U-Boot and ARM-Trusted-Firmware, sometimes without any proprietary blob left in the boot process. While each device and associated platform presents various specificities, they are abstracted away by generic software interfaces in upstream projects, where the source code for all the supported platforms and devices is merged in a single tree. However, the installation process for deploying the software on an actual device is not always straightforward, especially when starting with building the code. Although each project may provide (more or less comprehensive) instructions for producing a software image for the device, the required procedure for preparing and installing the produced images to the device can be rather technical and complex. These steps are generally specific to the platform or family of the device and often involve specific tools. Origami-Paper is a project that aims to ease the development, preparation and installation of free software and logic configuration projects related to hardware support. Technically, it consists of a build system with a collection of scripts, which provide a consistent interface to build, prepare and install upstream free boot software projects for specific devices. They allow simplifying each action involved in the process, by bringing the focus away from the specifics of each project's build system and usage, including tools specific to the device, platform or family. By reducing the overhead of the process, using free boot software becomes more accessible to non-developers! The Origami-Paper project will be presented through an overview of the rationale behind it, its development, its features and examples describing how to use it in practice. Additional areas of focus of the project will also be mentioned, such as automated deployment and providing information about the support status in free upstream projects related to hardware support for specific platforms and devices as well as documentation and both source and binary releases.

Un nombre croissant d'ordinateurs modernes, qu'il s'agisse d'ordinateurs x86 de bureau, portables ou encore d'appareils embarqués, contient des dispositifs de vérification du premier logiciel de démarrage. En pratique, cela signifie souvent que seul le logiciel de démarrage autorisé par le fabricant peut être exécuté sur ces appareils, causant de sérieux problèmes de liberté mais également de sécurité. Avec l'utilisation d'algorithmes de chiffrement asymétrique pour assurer l'authenticité des ces logiciels, une clef privée gardée secrète par le fabricant et une clef publique stockée en mémoire non-réinscriptible, il devient impossible pour les utilisateurs finaux de compiler, installer exécuter des logiciels de démarrage libres pour leur appareil. Cependant, il existe plusieurs exemples d'appareils sur lesquels la vérification du démarrage est implémentée d'une manière permettant aux utilisateurs de garder le contrôle de leurs appareils. En particulier, les appareils ChromeOS/ChromiumOS (CrOS) tels que les Chromebooks implémentent une vérification du démarrage fiable et qui n'empêche pas l'utilisation de logiciels libres. Mieux encore, cette vérification du démarrage est implémentée au travers de logiciels libres, à la fois au niveau du logiciel de démarrage et du micrologiciel de l'embedded controller. Cette présentation consistera ainsi en une description de l'état actuel des techniques de vérification de logiciel de démarrage. Il s'agira dans un premier temps d'en dégager les problématiques liées au logiciel libre et à la vie privée/sécurité et dans un second temps de présenter un modèle permettant d'apporter solution à ces problématiques.

Liberating the software running at the lower levels of the hardware we use, either on the main processor or on controllers and peripherals can reveal to be quite challenging. There is a series of (more or less) usual limitations to overcome in the process, each of them being a challenge for free software developers, with the potential of fatally blocking a free software implementation.

This talk will highlight the process of liberating the software running at the lower levels of devices we use. In particular, it will focus on each recurrent limitation that is encountered when freeing a device, with an insight on the process to overcoming them, when possible at all.

Various examples will be shown, drawn from experience liberating mobile devices at the operating system level (with Replicant), at the bootloader level and other devices such as a Chromebook laptop and another laptop's embedded controller.

Finally, the question of the free software replacement's installation process for end users will be mentioned, with positive and negative examples and suggestions for making the process less painful in general.

Replicant was started as a pragmatic way to achieve software freedom on mobile devices, as a fully free version of Android. Over the years, support was added for a dozen of different mainstream devices. However, most of these are severely flawed when it comes to software freedom and privacy/security. Thus, it was decided to focus the development effort on a few specific devices that perform better than others from those perspectives, instead of trying to catch up with the latest mainstream devices.

This talk will first cover what was accomplished by the Replicant project over the last few years and what milestones have been reached. This includes an overview of the work that was completed to support various devices, especially when it comes to writing free software replacements for proprietary components. Some of the most challenging examples will be highlighted and put in perspective as milestones for the project. In addition, some of the work on making the system better regarding privacy and security will be mentioned. Once the improvement of the situation is acknowledged, this talk will show how most of these devices are still fundamentally flawed, hence opening up two possible ways for the future of the project: adding support for more and more new devices and recent Android versions or focusing on a handful of devices that show real potential for being liberated. Hence, the second part of this presentation will introduce the recent efforts that were started to support devices that can take freedom to the next step. Some of these exciting devices will be presented in details, with a description of the journey to freeing them from the ground up!