Embedded Open Source Experts

Linux, Yocto and FPGAs

Integrating Linux and Yocto builds into different SoCs

From a Linux software perspective:

➤ Increased demand for Linux on FPGAs

➤ Many things to mange, both technical and practical

➤ FPGAs with integrated CPU cores – very similar many other SoCs

Here are some experiences and observations...

© Codiax 2019 ● Page 2 Why use Linux?

➤ De-facto standard

➤ Huge HW support

➤ FOSS

➤ Flexible

➤ Adaptable

➤ Stable

➤ Scalable

➤ Royalty free

➤ Vendor independent

➤ Large community

➤ Long lifetime

Why not Linux?

➤ Too big

➤ Real-time requirements

➤ Certification

➤ Boot time

➤ Licensing

➤ Too open?

Linux system example

Widgets for Desktop widgets 2D Application Media Application 3D Application Unity and Plasma possibly adaptations to Wayland/Mir possibly adaptations to Wayland/Mir possibly adaptations to Wayland/Mir Desktop Shells: User Interface Toolkits (in the form of libraries): Ubuntu Android l l 9 GNUstep e k 1 n 2 c h

R GTK+

o

o wxWidgets S a D y

m

D Pango ATK t . E i - m a

t Qt EFL SDL FLTK n s o M n Clutter h

r libwayland-client libwayland-client libwayland-client a i U n l g O ... i i a Cairo (Xr) l P N

C libwayland-client C n libwayland / COGL

G libX/libXCB E Display server: System libraries: System daemons: Alternative display servers: n n d o

weston, clayton, mutter, KWin d libmir-serv o r -

) t

e libxserver SF i v o

k window g m i e m d k a GLib r mir

s SurfaceFlinger d e n e d u

e X-Server o manager window a k window

GObject m mir libwayland-server a s glibc a u g M s X.Org metacity n w e i

Glib i k D d manager A manager t r t a a - Wayland Compositor - Xfree86 mutter d t µClibc o

GModule i s e k e Compiz

s AWM n w

u KWin s t o X-Win32 GThread y h c n u l c e ( s a a Compiz

GIO u N X11.app u B v - p

libinput P a D evdev kms (Kernel Mode Setting) ? kdbus ? kmod-fs-ext4 SELinux libhybris libbionic drm (Direct Rendering Manager) netfilter TOMOYO binder ashmem pmem Linux kernel, device drivers & other modules Smack wakelocks logger ... AppArmor radeon nouveau lima etna_viv freedreno tegra-re ALSA: emu20k1, ctxfi, hda... kmod-ltq-atm-vr9 ath9k Linux kernel Keyboard & Mouse CPU & GPU UMTS/CDMA/LTE Ethernet (Android-forked) Touch-Screen cache coherent L2-Caches Hardware GPS-receiver 802.11-(abc) BrailleDisplay main memory G-sensor Bluetooth

Source: https://en.wikipedia.org/wiki/File:Free_and_open-source-software_display_servers_and_UI_toolkits.svg + development tools = a lot of source code!

© Codiax 2019 ● Page 5 Linux system open source code

● Linux kernel ~ 20 MLOC + Bootloader + Libraries + System services + FOSS applications + Development tools

How to select, integrate, build and maintain?

© Codiax 2019 ● Page 6 OpenEmbedded / Yocto - A build system for embedded Linux

● What does such a build system do? – Automates the process of building a target system – Downloads, patches, configures, compiles/cross- compiles

● The Linux kernel ● Applications for a Linux root filesystem – Packages applications – Keeps track of application dependencies – Deploys generated images – Provides an SDK – Provides tools

© Codiax 2019 ● Page 7 What is OpenEmbedded?

● OE is the basis for many build systems, including Poky (and e.g. Ångström)

● Is the origin of Bitbake and OpenEmbedded- Core, that are now also part of Yocto Project ● Provides meta data, recipes and layers, for thousands of open source applications (not part of OpenEmbedded-Core) – http://layers.openembedded.org

© Codiax 2019 ● Page 8 Build system overview

Source: Yocto Project Quick Start manual

© Codiax 2019 ● Page 9 OpenEmbedded / Yocto

● Builds all – long build times

● Build caches ● Depends on external archives – Rebuilding old builds? – Local source code storage? – Local meta data mirrors ● FOSS Compliance

© Codiax 2019 ● Page 10 FOSS – Free and Open Source Software

FOSS licenses (typically) ensure and regulate

➤ The four basic freedoms – Freedom to use – Freedom to study – Freedom to redistribute – Freedom to modify

➤ Handling of derived works

➤ Proper attribution to copyright owners

➤ And more...

The Open Source Definition – http://opensource.org/docs/osd The Free Software Definition – https://www.gnu.org/philosophy/free-sw.html

HW oriented adaptations

Applications

Boot loader Kernel Init Services

FS

➤ HW specific BOOT

➤ Device tree (DTS) for boot loader and kernel

➤ Boot loader and kernel drivers

➤ Boot loader and kernel configuration

➤ Mapping of memory areas from kernel to user space process

➤ Real-time configuration + potential RT patches

Trends

● Linux and real-time - again

● Virtualization ● Security

© Codiax 2019 ● Page 13

? ? ? ? ? ?

Questions?

[email protected] www.codiax.se

© Codiax 2019 ● Page 14