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Diffstat (limited to 'doc/board/sipeed/maix.rst')
| -rw-r--r-- | doc/board/sipeed/maix.rst | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/doc/board/sipeed/maix.rst b/doc/board/sipeed/maix.rst index b1894f3a6f..efcde9aebf 100644 --- a/doc/board/sipeed/maix.rst +++ b/doc/board/sipeed/maix.rst @@ -75,6 +75,49 @@ console shall be opened immediately. Boot output should look like the following: Err: serial@38000000 => +OpenSBI +^^^^^^^ + +OpenSBI is an open source supervisor execution environment implementing the +RISC-V Supervisor Binary Interface Specification [1]. One of its features is +to intercept run-time exceptions, e.g. for unaligned access or illegal +instructions, and to emulate the failing instructions. + +The OpenSBI source can be downloaded via: + +.. code-block:: bash + + git clone https://github.com/riscv/opensbi + +As OpenSBI will be loaded at 0x80000000 we have to adjust the U-Boot text base. +Furthermore we have to enable building U-Boot for S-mode:: + + CONFIG_SYS_TEXT_BASE=0x80020000 + CONFIG_RISCV_SMODE=y + +Both settings are contained in sipeed_maix_smode_defconfig so we can build +U-Boot with: + +.. code-block:: bash + + make sipeed_maix_smode_defconfig + make + +To build OpenSBI with U-Boot as a payload: + +.. code-block:: bash + + cd opensbi + make \ + PLATFORM=kendryte/k210 \ + FW_PAYLOAD=y \ + FW_PAYLOAD_OFFSET=0x20000 \ + FW_PAYLOAD_PATH=<path to U-Boot>/u-boot-dtb.bin + +The value of FW_PAYLOAD_OFFSET must match CONFIG_SYS_TEXT_BASE - 0x80000000. + +The file to flash is build/platform/kendryte/k210/firmware/fw_payload.bin. + Loading Images ^^^^^^^^^^^^^^ @@ -363,3 +406,9 @@ Address Size Description interrupts) 0x8801f000 0x1000 credits ========== ========= =========== + +Links +----- + +[1] https://github.com/riscv/riscv-sbi-doc + RISC-V Supervisor Binary Interface Specification |