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| -rw-r--r-- | Documentation/devicetree/bindings/mtd/nand-controller.yaml | 179 |
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diff --git a/Documentation/devicetree/bindings/mtd/nand-controller.yaml b/Documentation/devicetree/bindings/mtd/nand-controller.yaml new file mode 100644 index 000000000..6fe2a3d8e --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/nand-controller.yaml @@ -0,0 +1,179 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/mtd/nand-controller.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: NAND Chip and NAND Controller Generic Binding + +maintainers: + - Miquel Raynal <miquel.raynal@bootlin.com> + - Richard Weinberger <richard@nod.at> + +description: | + The NAND controller should be represented with its own DT node, and + all NAND chips attached to this controller should be defined as + children nodes of the NAND controller. This representation should be + enforced even for simple controllers supporting only one chip. + + The ECC strength and ECC step size properties define the user + desires in terms of correction capability of a controller. Together, + they request the ECC engine to correct {strength} bit errors per + {size} bytes. + + The interpretation of these parameters is implementation-defined, so + not all implementations must support all possible + combinations. However, implementations are encouraged to further + specify the value(s) they support. + +properties: + $nodename: + pattern: "^nand-controller(@.*)?" + + "#address-cells": + const: 1 + + "#size-cells": + const: 0 + + ranges: true + +patternProperties: + "^nand@[a-f0-9]$": + type: object + properties: + reg: + description: + Contains the chip-select IDs. + + nand-ecc-mode: + description: + Desired ECC engine, either hardware (most of the time + embedded in the NAND controller) or software correction + (Linux will handle the calculations). soft_bch is deprecated + and should be replaced by soft and nand-ecc-algo. + $ref: /schemas/types.yaml#/definitions/string + enum: [none, soft, hw, hw_syndrome, hw_oob_first, on-die] + + nand-ecc-engine: + allOf: + - $ref: /schemas/types.yaml#/definitions/phandle + description: | + A phandle on the hardware ECC engine if any. There are + basically three possibilities: + 1/ The ECC engine is part of the NAND controller, in this + case the phandle should reference the parent node. + 2/ The ECC engine is part of the NAND part (on-die), in this + case the phandle should reference the node itself. + 3/ The ECC engine is external, in this case the phandle should + reference the specific ECC engine node. + + nand-use-soft-ecc-engine: + type: boolean + description: Use a software ECC engine. + + nand-no-ecc-engine: + type: boolean + description: Do not use any ECC correction. + + nand-ecc-placement: + allOf: + - $ref: /schemas/types.yaml#/definitions/string + - enum: [ oob, interleaved ] + description: + Location of the ECC bytes. This location is unknown by default + but can be explicitly set to "oob", if all ECC bytes are + known to be stored in the OOB area, or "interleaved" if ECC + bytes will be interleaved with regular data in the main area. + + nand-ecc-algo: + description: + Desired ECC algorithm. + $ref: /schemas/types.yaml#/definitions/string + enum: [hamming, bch, rs] + + nand-bus-width: + description: + Bus width to the NAND chip + $ref: /schemas/types.yaml#/definitions/uint32 + enum: [8, 16] + default: 8 + + nand-on-flash-bbt: + $ref: /schemas/types.yaml#/definitions/flag + description: + With this property, the OS will search the device for a Bad + Block Table (BBT). If not found, it will create one, reserve + a few blocks at the end of the device to store it and update + it as the device ages. Otherwise, the out-of-band area of a + few pages of all the blocks will be scanned at boot time to + find Bad Block Markers (BBM). These markers will help to + build a volatile BBT in RAM. + + nand-ecc-strength: + description: + Maximum number of bits that can be corrected per ECC step. + $ref: /schemas/types.yaml#/definitions/uint32 + minimum: 1 + + nand-ecc-step-size: + description: + Number of data bytes covered by a single ECC step. + $ref: /schemas/types.yaml#/definitions/uint32 + minimum: 1 + + nand-ecc-maximize: + $ref: /schemas/types.yaml#/definitions/flag + description: + Whether or not the ECC strength should be maximized. The + maximum ECC strength is both controller and chip + dependent. The ECC engine has to select the ECC config + providing the best strength and taking the OOB area size + constraint into account. This is particularly useful when + only the in-band area is used by the upper layers, and you + want to make your NAND as reliable as possible. + + nand-is-boot-medium: + $ref: /schemas/types.yaml#/definitions/flag + description: + Whether or not the NAND chip is a boot medium. Drivers might + use this information to select ECC algorithms supported by + the boot ROM or similar restrictions. + + nand-rb: + $ref: /schemas/types.yaml#/definitions/uint32-array + description: + Contains the native Ready/Busy IDs. + + rb-gpios: + description: + Contains one or more GPIO descriptor (the numper of descriptor + depends on the number of R/B pins exposed by the flash) for the + Ready/Busy pins. Active state refers to the NAND ready state and + should be set to GPIOD_ACTIVE_HIGH unless the signal is inverted. + + required: + - reg + +required: + - "#address-cells" + - "#size-cells" + +additionalProperties: true + +examples: + - | + nand-controller { + #address-cells = <1>; + #size-cells = <0>; + + /* controller specific properties */ + + nand@0 { + reg = <0>; + nand-ecc-mode = "soft"; + nand-ecc-algo = "bch"; + + /* NAND chip specific properties */ + }; + }; |