1 RISC-V Open Source Supervisor Binary Interface (OpenSBI)
2 ========================================================
4 The **RISC-V Supervisor Binary Interface (SBI)** is a recommended
7 1. A platform specific firmware (M-mode) and a general purpose
8 OS or hypervisor or bootloader (S-mode or HS-mode).
9 2. A hypervisor (HS-mode) and a general purpose OS or bootloader (VS-mode)
11 The *RISC-V SBI specification* is maintained as an independent project
12 by the RISC-V Foundation in [Github](https://github.com/riscv/riscv-sbi-doc)
14 OpenSBI aims to provides an open-source and extensible implementation of
15 the RISC-V SBI specification for case 1 mentioned above. OpenSBI
16 implementation can be easily extended by RISC-V platform or System-on-Chip
17 vendors to fit a particular hadware configuration.
19 OpenSBI provides three components:
21 1. *libsbi.a* - A generic OpenSBI static library
22 2. *libplatsbi.a* - Platform specific OpenSBI static library, that is,
23 libsbi.a plus platform specific hooks
24 3. *firmwares* - Platform specific bootable firmware binaries
26 Building and Installing generic *libsbi.a*
27 ------------------------------------------
29 For cross-compiling, the environment variable *CROSS_COMPILE* must
30 be defined to specify the toolchain executable name prefix, e.g.
31 *riscv64-unknown-elf-* if the gcc executable used is
32 *riscv64-unknown-elf-gcc*.
34 To build the generic OpenSBI library *libsbi.a*, simply execute:
39 All compiled binaries will be placed in the *build* directory.
40 To specify an alternate build directory target, run:
42 make O=<build_directory>
45 To generate files to be installed for using *libsbi.a* in other projects,
50 This will create the *install* directory with all necessary include files
51 and binary files under it. To specify an alternate installation directory,
54 make I=<install_directory> install
57 Building and Installing platform specific *libsbi.a* and firmwares
58 ------------------------------------------------------------------
60 The libplatsbi.a and firmware files are only built if the
61 *`PLATFORM=<platform_subdir>`* argument is specified on make command lines.
62 *`<platform_subdir>`* must specify the path to one of the leaf directories
63 under the *`platform`* directory. For example, to compile the library and
64 firmware for QEMU RISC-V *virt* machine, *`<platform_subdir>`*
65 should be *`qemu/virt`*.
67 To build *libsbi, libplatsbi, and firmwares* for a specific platform, run:
69 make PLATFORM=<platform_subdir>
74 make PLATFORM=<platform_subdir> O=<build_directory>
77 To install *libsbi, headers, libplatsbi, and firmwares*, run:
79 make PLATFORM=<platform_subdir> install
84 make PLATFORM=<platform_subdir> I=<install_directory> install`
87 In addition, platform specific make command-line options to top-level make
88 , such as *PLATFORM_<xyz>* or *FW_<abc>* can also be specified. These
89 options are described under *docs/platform/<platform_name>.md* and
90 *docs/firmware/<firmware_name>.md*.
95 A more detailed documenation is under the *docs* directory and organized
98 * *docs/platform_guide.md* - Guidelines for adding new platform support
99 * *docs/library_usage.md* - Guidelines for using the static library
100 * *docs/platform/<platform_name>.md* - Platform specific documentation for
101 the platform *<platform_name>*
102 * *docs/firmware/<firmware_name>.md* - Platform specific documentation for
103 the firmware *<firmware_name>*
105 The source code is also well documented. For source level documentation,
106 doxygen style is used. Please refer to [Doxygen manual]
107 (http://www.stack.nl/~dimitri/doxygen/manual.html) for details on this