Alexey Brodkin <Alexey.Brodkin@xxxxxxxxxxxx> writes: > ARC processors are supported in upstream kernel since v3.9 > and so far there was no documentation about them except some > Device Tree bindings. > > Fixing it with the simples set of docs now: > 1. Overview with pointers to other informational resources > 2. Autogenerated feature table > > Note though it's just the very beginning, there will be more > for sure given time as there're many things worth documenting > and in fact even contents itself is avaialble but just spread > in some other places. Now we'll try to keep all here and > then maintain it looking forward to match the state of development. > > Signed-off-by: Alexey Brodkin <abrodkin@xxxxxxxxxxxx> > Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> > Cc: Vineet Gupta <vgupta@xxxxxxxxxx> I've applied this set, but I have a couple of quibbles that it would be nice to see addressed... > Changes v1 -> v2: > * Spello "linux" -> "Linux" (Randy Dunlap) > > Documentation/arc/arc.rst | 81 ++++++++++++++++++++++++++++++++++ > Documentation/arc/features.rst | 3 ++ > Documentation/arc/index.rst | 17 +++++++ > Documentation/arch.rst | 1 + > MAINTAINERS | 1 + > 5 files changed, 103 insertions(+) > create mode 100644 Documentation/arc/arc.rst > create mode 100644 Documentation/arc/features.rst > create mode 100644 Documentation/arc/index.rst > > diff --git a/Documentation/arc/arc.rst b/Documentation/arc/arc.rst > new file mode 100644 > index 000000000000..249d03c6be8e > --- /dev/null > +++ b/Documentation/arc/arc.rst > @@ -0,0 +1,81 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +Linux kernel for ARC processors > +******************************* > + > +Other sources of information > +############################ > + > +Below are some resources where more information can be found on > +ARC processors and relevant open source projects. > + > +1. `<https://embarc.org/>`_ - Community portal for open source on ARC. > +Good place to start to find relevant FOSS projects, toolchain releases, > +news items and more. > + > +2. `<https://github.com/foss-for-synopsys-dwc-arc-processors>`_ - > +Home for all development activities regarding open source projects for > +ARC processors. Some of the projects are forks of various upstream projects, > +where "work in progress" is hosted prior to submission to upstream projects. > +Other projects are developed by Synopsys and made available to community > +as open source for use on ARC Processors. > + > +3. `<https://www.synopsys.com/designware-ip/processor-solutions.html>`_ - > +Official Synopsys ARC Processors website location, with access to some IP > +documentation (Programmer's Reference Manuals, AKA "PRM's", see > +`<https://www.synopsys.com/dw/doc.php/ds/cc/programmers-reference-manual-ARC-HS.pdf>`_) This manual requires registration (with a fair amount of information required) to get. That should at least be mentioned if we can't find a less obnoxious version out there. > +and commercial tools (Free nSIM, > +`<https://www.synopsys.com/cgi-bin/dwarcnsim/req1.cgi>`_ and > +MetaWare Light Edition, `<https://www.synopsys.com/cgi-bin/arcmwtk_lite/reg1.cgi>`_) > + > +Important note on ARC processors configurability > +################################################ > + > +ARC processors are highly configurable and several configurable options > +are supported in Linux. Some options are transparent to software > +(i.e cache geometries, some can be detected at runtime and configured > +and used accordingly, while some need to be explicitly selected or configured > +in the kernel's configuration utility (AKA "make menuconfig"). > + > +However not all configurable options are supported when an ARC processor > +is to run Linux. SoC design teams should refer to "Appendix E: > +Configuration for ARC Linux" in the ARC HS Databook for configurability > +guidelines. > + > +Following these guidelines and selecting valid configuration options > +up front is critical to help prevent any unwanted issues during > +SoC bringup and software development in general. > + > +Building the Linux kernel for ARC processors > +############################################ > + > +The process of kernel building for ARC processors is the same as for any other > +architecture and could be done in 2 ways: > + > +1. cross-compilation: process of compiling for ARC targets on a development > +host with a different processor architecture (generally x86_64/amd64). > + > +2. native compilation: process of compiling for ARC on a ARC platform > +(hardware board or a simulator like QEMU) with complete development environment > +(GNU toolchain, dtc, make etc) installed on the platform. These enumerated lists would render a lot more pleasantly if you actually formatted them as RST enumerated lists - with lines after the first indented. > +In both cases, up-to-date GNU toolchain for ARC for the host is needed. > +Synopsys offers prebuilt toolchain releases which can be used for this purpose, > +available from: > + > +1. Synopsys GNU toolchain releases: > +`<https://github.com/foss-for-synopsys-dwc-arc-processors/toolchain/releases>`_ > +2. Linux kernel compilers collection: > +`<https://mirrors.edge.kernel.org/pub/tools/crosstool/>`_ > +3. Bootlin's toolchain collection: `<https://toolchains.bootlin.com/>`_ These, in particular, render in a pretty ugly way. Thanks, jon
