L4Re/Fiasco.OC Patches

Current archive: L4Re-Fiasco.OC-patches-2020-06-06.tar.bz2

Initial archive: L4Re-Fiasco.OC-patches-2018-04-10.tar.bz2

Introduction

These patches complete basic support in the L4 Runtime Environment and Fiasco.OC microkernel for the MIPS Creator CI20, Ben NanoNote and Letux 400. Additional fixes and adjustments are present for compilation using GCC on Debian platforms (sufficient for the CI20) and using a Buildroot-generated GCC (required for the Ben NanoNote and Letux 400, with soft-float support not being fully provided by the Debian toolchains).

The current archive provides only the essential support, with additional support for various peripherals being provided by a separate distribution of programs and libraries called Landfall.

The initial archive provides both essential and peripheral support in order to demonstrate a functioning system on the different hardware platforms. However, working with patches to provide additional functionality is not an efficient activity and future effort will be directed towards Landfall as a means of delivering such functionality.

The Spectrum example on the Ben NanoNote and Letux 400

Summary

From the README.txt file provided:

File	Description
ci20-fiasco.diff	Fix to provide the rdhrw instruction
ci20-gcc-debian-fiasco.diff	Debian GCC cross-compiler prefix usage
ci20-gcc-debian-l4re.diff	Debian GCC cross-compiler prefix usage
ci20-platform.diff	Additional CI20 platform details
ci20-uart0.diff	Fix for output via UART0 instead of UART4
conf-makeconf-boot.diff	Path definitions for L4Re building
ingenic-mips-fbdrv.diff	Support for LCD devices in fb-drv
l4util-mips-thread.diff	Fix for static thread functions
letux400-fbdrv.diff	Letux 400 framebuffer driver support
mips-gcc-cpload.diff	Fix to allow GCC-generated code to work
ned-log-cap.diff	Support for specifying log capabilities
no-at.diff	Fix for Debian i386 architecture building
qi_lb60-fbdrv.diff	Ben NanoNote framebuffer driver support
qi_lb60-fiasco.diff	Ben NanoNote kernel support
qi_lb60-gcc-buildroot-fiasco.diff	Buildroot GCC cross-compiler prefix usage
qi_lb60-gcc-buildroot-l4re.diff	Buildroot GCC cross-compiler prefix usage
qi_lb60-l4re.diff	Ben NanoNote architecture support
qi_lb60-platform.diff	Ben NanoNote platform support

Patches made against upstream repository version r78.

Status

The information below describes the status of device support with the current archive when used together with the Landfall distribution.

CI20

The CI20 will boot and execute tasks. Progress can be followed using a UART connection.
Only 256MB RAM of the full 1GB RAM is currently supported, due to the base of RAM remaining at physical address zero. It is hoped that a trivial change of the base address will permit the use of the full 1GB.
The CPM peripheral support should permit the perusal and potential modification of various clock frequencies.
GPIO peripheral support is present and partly demonstrated.
I2C peripheral support is present and somewhat tested, although it appears unreliable, similar to experiences reported with other Ingenic SoCs under Linux. It can be used to interact with the real-time clock (RTC) chip (a PCF8563-compatible device), however.
HDMI output has been demonstrated, employing the HDMI peripheral's own I2C support to perform DDC communication and to retrieve display information. Unlike the Ingenic I2C peripheral, this appears to be reliable. The LCD peripheral is configured to provide a picture that is sent via the HDMI signal to a monitor, with a DVI-capable monitor having been used to test an appropriate signal.

Ben NanoNote and Letux 400

The CPM and GPIO peripherals are supported for the Ben and Letux, both being needed for LCD peripheral support which is also provided. The Letux PWM peripheral is also supported, being needed to drive the LCD panel backlight.
The Ben and Letux can boot, provide a framebuffer image and can start the framebuffer driver and the Mag graphical user interface multiplexer.
Keypad input support is provided for the Ben and Letux. This is not integrated with the input drivers because the intention is to provide device-specific resources and use separate server programs to access the hardware, rather than have these separate activities combined in the same program.
Shared executables now work. This required a change to the dynamic linker package that is now featured in the appropriate patch file.

Copyright and Licence

These patches are subject to copyright. L4Re and Fiasco.OC are mostly licensed under the GPL version 2. Please see the patched files and the patches themselves for more information about specific licences likely to apply to these patches.