[PATCH v8 5/5] dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
From: Chen Zhou <hidden>
Date: 2020-05-21 09:35:28
Also in:
kexec, linux-arm-kernel, linux-doc, lkml
Subsystem:
open firmware and flattened device tree bindings, the rest · Maintainers:
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
Add documentation for DT property used by arm64 kdump: linux,low-memory-range. "linux,low-memory-range" is an another memory region used for crash dump kernel devices. Signed-off-by: Chen Zhou <redacted> --- Documentation/devicetree/bindings/chosen.txt | 25 ++++++++++++++++++++ 1 file changed, 25 insertions(+)
diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt
index 45e79172a646..bfe6fb6976e6 100644
--- a/Documentation/devicetree/bindings/chosen.txt
+++ b/Documentation/devicetree/bindings/chosen.txt@@ -103,6 +103,31 @@ While this property does not represent a real hardware, the address and the size are expressed in #address-cells and #size-cells, respectively, of the root node. +linux,low-memory-range +---------------------- +This property (arm64 only) holds a base address and size, describing a +limited region below 4G. Similar to "linux,usable-memory-range", it is +an another memory range which may be considered available for use by the +kernel. + +e.g. + +/ { + chosen { + linux,low-memory-range = <0x0 0x70000000 0x0 0x10000000>; + linux,usable-memory-range = <0x202f 0xc0000000 0x0 0x40000000>; + }; +}; + +The main usage is for crash dump kernel devices when reserving crashkernel +above 4G. When reserving crashkernel above 4G, there may be two crash kernel +regions, one is below 4G, the other is above 4G. In order to distinct from +the high region, use this property to pass the low region. + +While this property does not represent a real hardware, the address +and the size are expressed in #address-cells and #size-cells, +respectively, of the root node. + linux,elfcorehdr ----------------
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2.20.1