efdd296323
This property has been extensively used for almost two decades already, a lot of device trees use it, this is not the preferred way to configure the ECC engines but we cannot just ignore it. Describe the property, list the exact strings which have once been supported and mark it deprecated. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Reviewed-by: Rob Herring <robh@kernel.org> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://lore.kernel.org/linux-mtd/20230619092916.3028470-5-miquel.raynal@bootlin.com
112 lines
3.7 KiB
YAML
112 lines
3.7 KiB
YAML
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/mtd/raw-nand-chip.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Raw NAND Chip Common Properties
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maintainers:
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- Miquel Raynal <miquel.raynal@bootlin.com>
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allOf:
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- $ref: nand-chip.yaml#
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description: |
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The ECC strength and ECC step size properties define the user
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desires in terms of correction capability of a controller. Together,
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they request the ECC engine to correct {strength} bit errors per
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{size} bytes for a particular raw NAND chip.
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The interpretation of these parameters is implementation-defined, so
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not all implementations must support all possible
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combinations. However, implementations are encouraged to further
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specify the value(s) they support.
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properties:
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$nodename:
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pattern: "^nand@[a-f0-9]$"
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reg:
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description:
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Contains the chip-select IDs.
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nand-ecc-placement:
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description:
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Location of the ECC bytes. This location is unknown by default
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but can be explicitly set to "oob", if all ECC bytes are
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known to be stored in the OOB area, or "interleaved" if ECC
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bytes will be interleaved with regular data in the main area.
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$ref: /schemas/types.yaml#/definitions/string
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enum: [ oob, interleaved ]
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deprecated: true
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nand-ecc-mode:
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description:
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Legacy ECC configuration mixing the ECC engine choice and
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configuration.
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$ref: /schemas/types.yaml#/definitions/string
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enum: [none, soft, soft_bch, hw, hw_syndrome, on-die]
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deprecated: true
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nand-bus-width:
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description:
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Bus width to the NAND chip
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$ref: /schemas/types.yaml#/definitions/uint32
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enum: [8, 16]
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default: 8
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nand-on-flash-bbt:
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description:
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With this property, the OS will search the device for a Bad
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Block Table (BBT). If not found, it will create one, reserve
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a few blocks at the end of the device to store it and update
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it as the device ages. Otherwise, the out-of-band area of a
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few pages of all the blocks will be scanned at boot time to
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find Bad Block Markers (BBM). These markers will help to
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build a volatile BBT in RAM.
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$ref: /schemas/types.yaml#/definitions/flag
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nand-ecc-maximize:
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description:
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Whether or not the ECC strength should be maximized. The
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maximum ECC strength is both controller and chip
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dependent. The ECC engine has to select the ECC config
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providing the best strength and taking the OOB area size
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constraint into account. This is particularly useful when
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only the in-band area is used by the upper layers, and you
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want to make your NAND as reliable as possible.
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$ref: /schemas/types.yaml#/definitions/flag
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nand-is-boot-medium:
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description:
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Whether or not the NAND chip is a boot medium. Drivers might
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use this information to select ECC algorithms supported by
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the boot ROM or similar restrictions.
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$ref: /schemas/types.yaml#/definitions/flag
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nand-rb:
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description:
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Contains the native Ready/Busy IDs.
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$ref: /schemas/types.yaml#/definitions/uint32-array
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rb-gpios:
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description:
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Contains one or more GPIO descriptor (the numper of descriptor
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depends on the number of R/B pins exposed by the flash) for the
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Ready/Busy pins. Active state refers to the NAND ready state and
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should be set to GPIOD_ACTIVE_HIGH unless the signal is inverted.
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wp-gpios:
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description:
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Contains one GPIO descriptor for the Write Protect pin.
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Active state refers to the NAND Write Protect state and should be
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set to GPIOD_ACTIVE_LOW unless the signal is inverted.
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maxItems: 1
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required:
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- reg
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# This is a generic file other binding inherit from and extend
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additionalProperties: true
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