forked from Mirrors/opensbi
5d4e3fb2ee
The default heap size will work for most platforms, but for some special platforms, the heap is too small to hold all the information or is too big so that it take too much ram. Introduce configurable heap should solve this problem and make all generic platforms happy. Add DT-based heap-size for the generic platform. Signed-off-by: Inochi Amaoto <inochiama@gmail.com> Reviewed-by: Xiang W <wxjstz@126.com> Reviewed-by: Anup Patel <anup@brainfault.org>
92 lines
2.5 KiB
Markdown
92 lines
2.5 KiB
Markdown
OpenSBI Device Tree Configuration Guideline
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==================================
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Some configurations of OpenSBI's Generic Platform can be described
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in the **device tree (DT) blob** (or flattened device tree) passed
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to the OpenSBI firmwares by the previous booting stage. OpenSBI will
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parse and use these configurations during the boot phase, but delete
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them from the device tree at the end of cold boot.
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### OpenSBI Configuration Node
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All nodes related to OpenSBI configuration should be under the OpenSBI
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configuration DT node. The **/chosen** DT node is the preferred parent
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of the OpenSBI configuration DT node.
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The DT properties of a domain configuration DT node are as follows:
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* **compatible** (Mandatory) - The compatible string of the OpenSBI
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configuration. This DT property should have value *"opensbi,config"*
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* **cold-boot-harts** (Optional) - If a platform lacks an override
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cold_boot_allowed() mechanism, this DT property specifies that a
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set of harts is permitted to perform a cold boot. Otherwise, all
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harts are allowed to cold boot.
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* **heap-size** (Optional) - When present, the specified value is used
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as the size of the heap in bytes.
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* **system-suspend-test** (Optional) - When present, enable a system
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suspend test implementation which simply waits five seconds and issues a WFI.
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The OpenSBI Configuration Node will be deleted at the end of cold boot
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(replace the node (subtree) with nop tags).
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### Example
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```text
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chosen {
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opensbi-config {
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compatible = "opensbi,config";
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cold-boot-harts = <&cpu1 &cpu2 &cpu3 &cpu4>;
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heap-size = <0x400000>;
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system-suspend-test;
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};
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};
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cpus {
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#address-cells = <1>;
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#size-cells = <0>;
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timebase-frequency = <10000000>;
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cpu0: cpu@0 {
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device_type = "cpu";
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reg = <0x00>;
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compatible = "riscv";
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...
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};
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cpu1: cpu@1 {
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device_type = "cpu";
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reg = <0x01>;
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compatible = "riscv";
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...
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};
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cpu2: cpu@2 {
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device_type = "cpu";
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reg = <0x02>;
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compatible = "riscv";
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...
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};
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cpu3: cpu@3 {
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device_type = "cpu";
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reg = <0x03>;
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compatible = "riscv";
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...
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};
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cpu4: cpu@4 {
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device_type = "cpu";
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reg = <0x04>;
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compatible = "riscv";
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...
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};
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};
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uart1: serial@10011000 {
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...
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};
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```
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