2021-11-12 06:50:59 +00:00
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.. SPDX-License-Identifier: GPL-2.0
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Linux kernel for ARC processors
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*******************************
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Other sources of information
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############################
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Below are some resources where more information can be found on
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ARC processors and relevant open source projects.
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2021-12-02 21:57:47 +00:00
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- `<https://embarc.org>`_ - Community portal for open source on ARC.
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Good place to start to find relevant FOSS projects, toolchain releases,
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news items and more.
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- `<https://github.com/foss-for-synopsys-dwc-arc-processors>`_ -
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Home for all development activities regarding open source projects for
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ARC processors. Some of the projects are forks of various upstream projects,
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where "work in progress" is hosted prior to submission to upstream projects.
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Other projects are developed by Synopsys and made available to community
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as open source for use on ARC Processors.
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- `Official Synopsys ARC Processors website
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<https://www.synopsys.com/designware-ip/processor-solutions.html>`_ -
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location, with access to some IP documentation (`Programmer's Reference
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Manual, AKA PRM for ARC HS processors
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<https://www.synopsys.com/dw/doc.php/ds/cc/programmers-reference-manual-ARC-HS.pdf>`_)
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and free versions of some commercial tools (`Free nSIM
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<https://www.synopsys.com/cgi-bin/dwarcnsim/req1.cgi>`_ and
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`MetaWare Light Edition <https://www.synopsys.com/cgi-bin/arcmwtk_lite/reg1.cgi>`_).
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Please note though, registration is required to access both the documentation and
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the tools.
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2021-11-12 06:50:59 +00:00
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Important note on ARC processors configurability
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################################################
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ARC processors are highly configurable and several configurable options
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are supported in Linux. Some options are transparent to software
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(i.e cache geometries, some can be detected at runtime and configured
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and used accordingly, while some need to be explicitly selected or configured
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in the kernel's configuration utility (AKA "make menuconfig").
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However not all configurable options are supported when an ARC processor
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is to run Linux. SoC design teams should refer to "Appendix E:
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Configuration for ARC Linux" in the ARC HS Databook for configurability
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guidelines.
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Following these guidelines and selecting valid configuration options
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up front is critical to help prevent any unwanted issues during
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SoC bringup and software development in general.
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Building the Linux kernel for ARC processors
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############################################
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The process of kernel building for ARC processors is the same as for any other
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architecture and could be done in 2 ways:
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2021-12-02 21:57:47 +00:00
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- Cross-compilation: process of compiling for ARC targets on a development
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host with a different processor architecture (generally x86_64/amd64).
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- Native compilation: process of compiling for ARC on a ARC platform
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(hardware board or a simulator like QEMU) with complete development environment
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(GNU toolchain, dtc, make etc) installed on the platform.
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2021-11-12 06:50:59 +00:00
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In both cases, up-to-date GNU toolchain for ARC for the host is needed.
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Synopsys offers prebuilt toolchain releases which can be used for this purpose,
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available from:
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2021-12-02 21:57:47 +00:00
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- Synopsys GNU toolchain releases:
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`<https://github.com/foss-for-synopsys-dwc-arc-processors/toolchain/releases>`_
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- Linux kernel compilers collection:
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`<https://mirrors.edge.kernel.org/pub/tools/crosstool>`_
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- Bootlin's toolchain collection: `<https://toolchains.bootlin.com>`_
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2021-11-12 06:50:59 +00:00
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Once the toolchain is installed in the system, make sure its "bin" folder
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is added in your ``PATH`` environment variable. Then set ``ARCH=arc`` &
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``CROSS_COMPILE=arc-linux`` (or whatever matches installed ARC toolchain prefix)
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and then as usual ``make defconfig && make``.
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This will produce "vmlinux" file in the root of the kernel source tree
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usable for loading on the target system via JTAG.
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If you need to get an image usable with U-Boot bootloader,
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type ``make uImage`` and ``uImage`` will be produced in ``arch/arc/boot``
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folder.
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