Re: [PATCH v4 08/21] dt-bindings: reserved-memory: Add qcom,ramoops binding

Pavan Kondeti
2023-06-28T14:11:48Z

On Wed, Jun 28, 2023 at 06:04:35PM +0530, Mukesh Ojha wrote:
> Qualcomm ramoops minidump logger provide a means of storing
> the ramoops data to some dynamically reserved memory instead
> of traditionally implemented ramoops where the region should
> be statically fixed ram region. Its device tree binding
> would be exactly same as ramoops device tree binding and is
> going to contain traditional ramoops frontend data and this
> content will be collected via Qualcomm minidump infrastructure
> provided from the boot firmware.
>
> Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
> ---
> .../devicetree/bindings/soc/qcom/qcom,ramoops.yaml | 126 +++++++++++++++++++++
> 1 file changed, 126 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/soc/qcom/qcom,ramoops.yaml
>
> diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,ramoops.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,ramoops.yaml
> new file mode 100644
> index 000000000000..b1fdcf3f8ad4
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,ramoops.yaml
> @@ -0,0 +1,126 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/soc/qcom/qcom,ramoops.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Qualcomm Ramoops minidump logger
> +
> +description: |
> + Qualcomm ramoops minidump logger provide a means of storing the ramoops
> + data to some dynamically reserved memory instead of traditionally
> + implemented ramoops where the region should be statically fixed ram
> + region. Because of its similarity with ramoops it will also have same
> + set of property what ramoops have it in its schema and is going to
> + contain traditional ramoops frontend data and this region will be
> + collected via Qualcomm minidump infrastructure provided from the
> + boot firmware.
> +
> +maintainers:
> + - Mukesh Ojha <quic_mojha@quicinc.com>
> +
> +properties:
> + compatible:
> + items:
> + - enum:
> + - qcom,sm8450-ramoops
> + - const: qcom,ramoops
> +
> + memory-region:
> + maxItems: 1
> + description: handle to memory reservation for qcom,ramoops region.
> +
> + 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".
> +

Most of the properties you added here are already documented at
Documentation/devicetree/bindings/reserved-memory/ramoops.yaml

Can't we just reference them here? would something like work?

max-reason:
$ref: "../../reserved-memory/ramoops.yaml#/properties/max-reason

> +unevaluatedProperties: false
> +

will there be any additional properties be added dynamically? if not,
should not we use "additionalProperties: false" here?

Thanks,
Pavan