dt-bindings: reserved-memory: ramoops: Convert txt bindings to yaml

Ramoops oops/panic logger

=========================

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.

Required properties:

- compatible: must be "ramoops"

- reg: region of memory that is preserved between reboots

Optional properties:

- ecc-size: enables ECC support and specifies ECC buffer size in bytes

  (defaults to 0: no ECC)

- record-size: maximum size in bytes of each kmsg dump.

  (defaults to 0: disabled)

- console-size: size in bytes of log buffer reserved for kernel messages

  (defaults to 0: disabled)

- ftrace-size: size in bytes of log buffer reserved for function tracing and

  profiling (defaults to 0: disabled)

- pmsg-size: size in bytes of log buffer reserved for userspace messages

  (defaults to 0: disabled)

- mem-type: if present, sets the type of mapping is to be used to map the

  reserved region. mem-type: 0 = write-combined (default), 1 = unbuffered,

  2 = cached.

- unbuffered: deprecated, 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".

- max-reason: if present, sets maximum type of kmsg dump reasons to store

  (defaults to 2: log Oopses and Panics). 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 KMSG_DUMP_OOPS, otherwise KMSG_DUMP_MAX.

- no-dump-oops: deprecated, use max_reason instead. If present, and

  max_reason is not specified, it is equivalent to max_reason = 1

  (KMSG_DUMP_PANIC).

- flags: if present, pass ramoops behavioral flags (defaults to 0,

  see include/linux/pstore_ram.h RAMOOPS_FLAG_* for flag values).

# 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>;

            };

        };

    };