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| author | Cheng Yang <yangcheng.work@foxmail.com> | 2024-02-08 11:14:33 +0800 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2024-02-20 16:05:21 +0530 |
| commit | 23e7e483ee86123dc41f5bcb495ab22054a08697 (patch) | |
| tree | 08fc48d5a51b79e4e499a1b924e4787046ca8687 /docs | |
| parent | 67ce5a763cfbcfb2edca7eab3d383e15d1a7330f (diff) | |
| download | opensbi-23e7e483ee86123dc41f5bcb495ab22054a08697.zip opensbi-23e7e483ee86123dc41f5bcb495ab22054a08697.tar.gz opensbi-23e7e483ee86123dc41f5bcb495ab22054a08697.tar.bz2 | |
docs: Add OpenSBI DT configuration guide.
This patch add docs/opensbi_config.md which describes the
"/chosen/opensbi-config" DT node and properties
Signed-off-by: Cheng Yang <yangcheng.work@foxmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/doxygen.cfg | 1 | ||||
| -rw-r--r-- | docs/opensbi_config.md | 83 |
2 files changed, 84 insertions, 0 deletions
diff --git a/docs/doxygen.cfg b/docs/doxygen.cfg index 82f31a7..608cb1c 100644 --- a/docs/doxygen.cfg +++ b/docs/doxygen.cfg @@ -796,6 +796,7 @@ INPUT = @@SRC_DIR@@/README.md \ @@SRC_DIR@@/docs/platform_requirements.md \ @@SRC_DIR@@/docs/library_usage.md \ @@SRC_DIR@@/docs/domain_support.md \ + @@SRC_DIR@@/docs/opensbi_config.md \ @@SRC_DIR@@/docs/firmware \ @@SRC_DIR@@/docs/platform \ @@SRC_DIR@@/include \ diff --git a/docs/opensbi_config.md b/docs/opensbi_config.md new file mode 100644 index 0000000..0c42443 --- /dev/null +++ b/docs/opensbi_config.md @@ -0,0 +1,83 @@ +OpenSBI Device Tree Configuration Guideline +================================== + +Some configurations of OpenSBI's Generic Platform can be described +in the **device tree (DT) blob** (or flattened device tree) passed +to the OpenSBI firmwares by the previous booting stage. OpenSBI will +parse and use these configurations during the boot phase, but delete +them from the device tree at the end of cold boot. + +### OpenSBI Configuration Node + +All nodes related to OpenSBI configuration should be under the OpenSBI +configuration DT node. The **/chosen** DT node is the preferred parent +of the OpenSBI configuration DT node. + +The DT properties of a domain configuration DT node are as follows: + +* **compatible** (Mandatory) - The compatible string of the OpenSBI + configuration. This DT property should have value *"opensbi,config"* + +* **cold-boot-harts** (Optional) - If a platform lacks an override + cold_boot_allowed() mechanism, this DT property specifies that a + set of harts is permitted to perform a cold boot. Otherwise, all + harts are allowed to cold boot. + +The OpenSBI Configuration Node will be deleted at the end of cold boot +(replace the node (subtree) with nop tags). + +### Example + +```text + chosen { + opensbi-config { + compatible = "opensbi,config"; + cold-boot-harts = <&cpu1 &cpu2 &cpu3 &cpu4>; + }; + }; + + cpus { + #address-cells = <1>; + #size-cells = <0>; + timebase-frequency = <10000000>; + + cpu0: cpu@0 { + device_type = "cpu"; + reg = <0x00>; + compatible = "riscv"; + ... + }; + + cpu1: cpu@1 { + device_type = "cpu"; + reg = <0x01>; + compatible = "riscv"; + ... + }; + + cpu2: cpu@2 { + device_type = "cpu"; + reg = <0x02>; + compatible = "riscv"; + ... + }; + + cpu3: cpu@3 { + device_type = "cpu"; + reg = <0x03>; + compatible = "riscv"; + ... + }; + + cpu4: cpu@4 { + device_type = "cpu"; + reg = <0x04>; + compatible = "riscv"; + ... + }; + }; + + uart1: serial@10011000 { + ... + }; +``` |