FreeBSD/Linux Kernel Cross Reference
sys/contrib/device-tree/Bindings/reserved-memory/ramoops.yaml

     # 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>;
               };
           };
       };

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