diff options
| author | Anup Patel <anup.patel@wdc.com> | 2019-04-29 12:50:33 +0530 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2019-05-10 12:26:22 +0530 |
| commit | 392749f6338ac8a63ce5492770caa4fb75ad6b96 (patch) | |
| tree | 671c7c5043f4ef10f041f3be9ffa2721a378de1b /docs/firmware/fw_dynamic.md | |
| parent | a4c2f50b640a4e93e0192718cfabb9686c6ca9a0 (diff) | |
docs: Add documentation about dynamic firmware
This patch adds documenation about dynamic firmware.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Diffstat (limited to 'docs/firmware/fw_dynamic.md')
| -rw-r--r-- | docs/firmware/fw_dynamic.md | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/docs/firmware/fw_dynamic.md b/docs/firmware/fw_dynamic.md new file mode 100644 index 0000000..041b6cc --- /dev/null +++ b/docs/firmware/fw_dynamic.md @@ -0,0 +1,35 @@ +OpenSBI Firmware with Dynamic Information *FW_DYNAMIC* +====================================================== + +OpenSBI **firmware with dynamic info (FW_DYNAMIC)** is a firmware which gets +information about next booting stage (e.g. a bootloader or an OS) and runtime +OpenSBI library options from previous booting stage. + +The previous booting stage will pass information to *FW_DYNAMIC* by creating +*struct fw_dynamic_info* in memory and passing it's address to *FW_DYNAMIC* +via *a2* register of RISC-V CPU. + +A *FW_DYNAMIC* firmware is particularly useful when the booting stage executed +prior to OpenSBI firmware is capable of loading both the OpenSBI firmware and +the booting stage binary to follow OpenSBI firmware. + +*FW_DYNAMIC* Compilation +------------------------ + +A platform can enable *FW_DYNAMIC* firmware using any of the following methods. + +1. Specifying `FW_DYNAMIC=y` on the top level `make` command line. +2. Specifying `FW_DYNAMIC=y` in the target platform *config.mk* configuration +file. + +The compiled *FW_DYNAMIC* firmware ELF file is named *fw_dynamic.elf*. It's +expanded image file is *fw_dynamic.bin*. Both files are created in the platform +specific build directory under the *build/platform/<platform_subdir>/firmware* +directory. + +*FW_DYNAMIC* Firmware Configuration Options +------------------------------------------- + +The *FW_DYNAMIC* firmware does not requires any platform specific configuration +parameters because all required information is passed by previous booting stage +at runtime via *struct fw_dynamic_info*. |