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- .. 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.
- - `<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.
- - `<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.
- - `Official Synopsys ARC Processors website
- <https://www.synopsys.com/designware-ip/processor-solutions.html>`_ -
- location, with access to some IP documentation (`Programmer's Reference
- Manual, AKA PRM for ARC HS processors
- <https://www.synopsys.com/dw/doc.php/ds/cc/programmers-reference-manual-ARC-HS.pdf>`_)
- and free versions of some 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>`_).
- Please note though, registration is required to access both the documentation and
- the tools.
- 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:
- - Cross-compilation: process of compiling for ARC targets on a development
- host with a different processor architecture (generally x86_64/amd64).
- - 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.
- 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:
- - Synopsys GNU toolchain releases:
- `<https://github.com/foss-for-synopsys-dwc-arc-processors/toolchain/releases>`_
- - Linux kernel compilers collection:
- `<https://mirrors.edge.kernel.org/pub/tools/crosstool>`_
- - Bootlin's toolchain collection: `<https://toolchains.bootlin.com>`_
- Once the toolchain is installed in the system, make sure its "bin" folder
- is added in your ``PATH`` environment variable. Then set ``ARCH=arc`` &
- ``CROSS_COMPILE=arc-linux`` (or whatever matches installed ARC toolchain prefix)
- and then as usual ``make defconfig && make``.
- This will produce "vmlinux" file in the root of the kernel source tree
- usable for loading on the target system via JTAG.
- If you need to get an image usable with U-Boot bootloader,
- type ``make uImage`` and ``uImage`` will be produced in ``arch/arc/boot``
- folder.
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