43 lines
2 KiB
Markdown
43 lines
2 KiB
Markdown
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OpenSBI Platform Support Guideline
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==================================
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The OpenSBI platform support allows an implementation to define a set of
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platform-specific hooks (hardware manipulation functions) in the form of a
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*struct sbi_platform* data structure instance. This instance is required by
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the platform-independent *libsbi.a* to execute platform-specific operations.
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Each of the reference platform supports provided by OpenSBI defines an instance
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of the *struct sbi_platform* data structure. For each supported platform,
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*libplatsbi.a* integrates this instance with *libsbi.a* to create a
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platform-specific OpenSBI static library. This library is installed
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in *<install_directory>/platform/<platform_subdir>/lib/libplatsbi.a*
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OpenSBI also provides implementation examples of bootable runtime firmwares for
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the supported platforms. These firmwares are linked against *libplatsbi.a*.
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Firmware binaries are installed in
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*<install_directory>/platform/<platform_subdir>/bin*. These firmwares can be
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used as executable runtime firmwares on the supported platforms as a replacement
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for the legacy *riskv-pk* boot loader (BBL).
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A complete doxygen-style documentation of *struct sbi_platform* and related
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APIs is available in the file *include/sbi/sbi_platform.h*.
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Adding support for a new platform
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---------------------------------
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Support for a new platform named *<xyz>* can be added as follows:
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1. Create a directory named *<xyz>* under the *platform/* directory.
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2. Create a platform configuration file named *config.mk* under the
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*platform/<xyz>/* directory. This configuration file will provide
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compiler flags, and select firmware options.
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3. Create a *platform/<xyz>/objects.mk* file for listing the
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platform-specific object files to be compiled.
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4. Create a *platform/<xyz>/platform.c* file providing a *struct sbi_platform*
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instance.
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A platform support code template is available under the *platform/template*
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directory. Copying this directory and its content as a new directory named
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*<xyz>* under the *platform/* directory will create all the files mentioned
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above.
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