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After years of trying to find the reason for random kernel crashes while both CPU and SATA are under load it has been found. Some odd commented-out #defines in kref's single-port driver [1] which were copied from the vendor driver made me develop a theory: The IO-mapped memory area for DMA descriptors apparetly got some holes just before the alignment boundaries. This feels like an off-by-one bug in the hardware or maybe those fields are used internally by the SATA controller's firmware. Whatever the cause is: they cannot be used and trying to use them results in reading back unexpected stuff and ends up with oopsing Unable to handle kernel paging request at virtual address d085c004 Work around the issue by reducing the area used for bmdma descriptors. This reduces SATA performance (iops) quite a bit, but finally makes things work reliably. Possibly one could optimize this much more by really just skipping the holes in that memory area -- however, that seems to be non-trivial with the driver and libata in it's current form (suggestions are welcome). The 'proper' way to have good SATA performance would be to make use of the hardware RAID features (one can use the JBOD mode to access even just a single disc transparently through the RAID controller integrated in the SATA host instead of accessing the SATA ports 'raw' as we do now). [1]: https://github.com/kref/linux-oxnas/blob/master/drivers/ata/sata_oxnas.c#L25 Signed-off-by: Daniel Golle <daniel@makrotopia.org> |
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OpenWrt Project is a Linux operating system targeting embedded devices. Instead of trying to create a single, static firmware, OpenWrt provides a fully writable filesystem with package management. This frees you from the application selection and configuration provided by the vendor and allows you to customize the device through the use of packages to suit any application. For developers, OpenWrt is the framework to build an application without having to build a complete firmware around it; for users this means the ability for full customization, to use the device in ways never envisioned.
Sunshine!
Development
To build your own firmware you need a GNU/Linux, BSD or MacOSX system (case sensitive filesystem required). Cygwin is unsupported because of the lack of a case sensitive file system.
Requirements
You need the following tools to compile OpenWrt, the package names vary between distributions. A complete list with distribution specific packages is found in the Build System Setup documentation.
gcc binutils bzip2 flex python3 perl make find grep diff unzip gawk getopt
subversion libz-dev libc-dev
Quickstart
-
Run
./scripts/feeds update -a
to obtain all the latest package definitions defined in feeds.conf / feeds.conf.default -
Run
./scripts/feeds install -a
to install symlinks for all obtained packages into package/feeds/ -
Run
make menuconfig
to select your preferred configuration for the toolchain, target system & firmware packages. -
Run
make
to build your firmware. This will download all sources, build the cross-compile toolchain and then cross-compile the GNU/Linux kernel & all chosen applications for your target system.
Related Repositories
The main repository uses multiple sub-repositories to manage packages of
different categories. All packages are installed via the OpenWrt package
manager called opkg
. If you're looking to develop the web interface or port
packages to OpenWrt, please find the fitting repository below.
-
LuCI Web Interface: Modern and modular interface to control the device via a web browser.
-
OpenWrt Packages: Community repository of ported packages.
-
OpenWrt Routing: Packages specifically focused on (mesh) routing.
Support Information
For a list of supported devices see the OpenWrt Hardware Database
Documentation
Support Community
- Forum: For usage, projects, discussions and hardware advise.
- Support Chat: Channel
#openwrt
on freenode.net.
Developer Community
- Bug Reports: Report bugs in OpenWrt
- Dev Mailing List: Send patches
- Dev Chat: Channel
#openwrt-devel
on freenode.net.
License
OpenWrt is licensed under GPL-2.0