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| -rw-r--r-- | Documentation/devicetree/bindings/reserved-memory/ramoops.yaml | 144 |
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diff --git a/Documentation/devicetree/bindings/reserved-memory/ramoops.yaml b/Documentation/devicetree/bindings/reserved-memory/ramoops.yaml new file mode 100644 index 000000000..0391871cf --- /dev/null +++ b/Documentation/devicetree/bindings/reserved-memory/ramoops.yaml @@ -0,0 +1,144 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: "http://devicetree.org/schemas/reserved-memory/ramoops.yaml#" +$schema: "http://devicetree.org/meta-schemas/core.yaml#" + +title: Ramoops oops/panic logger + +description: | + ramoops provides persistent RAM storage for oops and panics, so they can be + recovered after a reboot. This is a child-node of "/reserved-memory", and + is named "ramoops" after the backend, rather than "pstore" which is the + subsystem. + + Parts of this storage may be set aside for other persistent log buffers, such + as kernel log messages, or for optional ECC error-correction data. The total + size of these optional buffers must fit in the reserved region. + + Any remaining space will be used for a circular buffer of oops and panic + records. These records have a configurable size, with a size of 0 indicating + that they should be disabled. + + At least one of "record-size", "console-size", "ftrace-size", or "pmsg-size" + must be set non-zero, but are otherwise optional as listed below. + +maintainers: + - Kees Cook <keescook@chromium.org> + +allOf: + - $ref: "reserved-memory.yaml" + +properties: + compatible: + const: ramoops + + reg: + description: region of memory that is preserved between reboots + + ecc-size: + $ref: /schemas/types.yaml#/definitions/uint32 + description: enables ECC support and specifies ECC buffer size in bytes + default: 0 # no ECC + + record-size: + $ref: /schemas/types.yaml#/definitions/uint32 + description: maximum size in bytes of each kmsg dump + default: 0 + + console-size: + $ref: /schemas/types.yaml#/definitions/uint32 + description: size in bytes of log buffer reserved for kernel messages + default: 0 + + ftrace-size: + $ref: /schemas/types.yaml#/definitions/uint32 + description: size in bytes of log buffer reserved for function tracing and profiling + default: 0 + + pmsg-size: + $ref: /schemas/types.yaml#/definitions/uint32 + description: size in bytes of log buffer reserved for userspace messages + default: 0 + + mem-type: + $ref: /schemas/types.yaml#/definitions/uint32 + description: if present, sets the type of mapping is to be used to map the reserved region. + default: 0 + oneOf: + - const: 0 + description: write-combined + - const: 1 + description: unbuffered + - const: 2 + description: cached + + max-reason: + $ref: /schemas/types.yaml#/definitions/uint32 + default: 2 # log oopses and panics + maximum: 0x7fffffff + description: | + If present, sets maximum type of kmsg dump reasons to store. + This can be set to INT_MAX to store all kmsg dumps. + See include/linux/kmsg_dump.h KMSG_DUMP_* for other kmsg dump reason values. + Setting this to 0 (KMSG_DUMP_UNDEF), means the reason filtering will be + controlled by the printk.always_kmsg_dump boot param. + If unset, it will be 2 (KMSG_DUMP_OOPS), otherwise 5 (KMSG_DUMP_MAX). + + flags: + $ref: /schemas/types.yaml#/definitions/uint32 + default: 0 + description: | + If present, pass ramoops behavioral flags + (see include/linux/pstore_ram.h RAMOOPS_FLAG_* for flag values). + + no-dump-oops: + deprecated: true + type: boolean + description: | + Use max_reason instead. If present, and max_reason is not specified, + it is equivalent to max_reason = 1 (KMSG_DUMP_PANIC). + + unbuffered: + deprecated: true + type: boolean + description: | + Use mem_type instead. If present, and mem_type is not specified, + it is equivalent to mem_type = 1 and uses unbuffered mappings to map + the reserved region (defaults to buffered mappings mem_type = 0). + If both are specified -- "mem_type" overrides "unbuffered". + +unevaluatedProperties: false + +required: + - compatible + - reg + +anyOf: + - required: [record-size] + - required: [console-size] + - required: [ftrace-size] + - required: [pmsg-size] + +examples: + - | + / { + compatible = "foo"; + model = "foo"; + #address-cells = <1>; + #size-cells = <1>; + + reserved-memory { + #address-cells = <1>; + #size-cells = <1>; + ranges; + + ramoops@bfdf0000 { + compatible = "ramoops"; + reg = <0xbfdf0000 0x10000>; /* 64kB */ + console-size = <0x8000>; /* 32kB */ + record-size = <0x400>; /* 1kB */ + ecc-size = <16>; + }; + }; + }; |