Re: [PATCH v5 4/4] memory: Add ECC properties

On Wed, Aug 30, 2023 at 6:18 PM Simon Glass sjg@chromium.org wrote:

Some memories provide ECC detection and/or correction. For software which wants to check memory, it is helpful to see which regions provide this feature.

Add this as a property of the /memory nodes, since it presumably follows the hardware-level memory system.

Signed-off-by: Simon Glass sjg@chromium.org

Changes in v5:

• Redo to make this property specific to ECC
• Provide properties both for detection and correction

Changes in v3:

• Add new patch to update the /memory nodes

dtschema/schemas/memory.yaml | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)

diff --git a/dtschema/schemas/memory.yaml b/dtschema/schemas/memory.yaml index 1d74410..944aa9f 100644 --- a/dtschema/schemas/memory.yaml +++ b/dtschema/schemas/memory.yaml @@ -34,7 +34,37 @@ patternProperties: description: For the purpose of identification, each NUMA node is associated with a unique token known as a node id.

•  ecc-detection:
  

•    $ref: /schemas/types.yaml#/definitions/string
  

•    enum:
  

•      - none
  

•      - single-bit
  

•      - multi-bit
  

•    description: |
  

•      If present, this inidcates the type of memory errors which can be
  

typo

•      detected and reported by the Error-Correction Code (ECC) memory
  

•      subsystem:
  
  

•        none       - No error detection is possible
  

•        single-bit - Detects and reports single-bit ECC errors
  

•        multi-bit  - Detects and reports multiple-bit ECC errors
  

I don't think 'multi' is specific enough. Perhaps this should be an int instead with how many bits. (And '-bits' is a standard unit suffix so a type isn't needed)

•      If not present, this is equivalent to 'none'.
  

Can be expressed as schema:

default: none

Though if that's the default why have it as a value? (It's fine though)

•  ecc-correction:
  

•    $ref: /schemas/types.yaml#/definitions/string
  

•    enum:
  

•      - none
  

•      - single-bit
  

•      - multi-bit
  

•    description: |
  

•      If present, this inidcates the type of memory errors which can be
  

typo

•      corrected by the Error-Correction Code (ECC) memory subsystem:
  

•        none       - No error correction is possible
  

•        single-bit - Corrects single-bit ECC errors
  

•        multi-bit  - Corrects multiple-bit ECC errors
  

•      If not present, this is equivalent to 'none'.
  

One issue is with 2 properties nonsensical combinations are allowed. Not really any way to handle that in the schema though.

Rob