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