linuxdebug/Documentation/devicetree/bindings/mtd/mtd-physmap.yaml

# SPDX-License-Identifier: GPL-2.0
%YAML 1.2
---
$id: http://devicetree.org/schemas/mtd/mtd-physmap.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: CFI or JEDEC memory-mapped NOR flash, MTD-RAM (NVRAM...)

maintainers:
  - Rob Herring <robh@kernel.org>

description: |
  Flash chips (Memory Technology Devices) are often used for solid state
  file systems on embedded devices.  

properties:
  compatible:
    oneOf:
      - items:
          - enum:
              - amd,s29gl01gp
              - amd,s29gl032a
              - amd,s29gl256n
              - amd,s29gl512n
              - arm,versatile-flash
              - arm,vexpress-flash
              - cortina,gemini-flash
              - cypress,hyperflash
              - ge,imp3a-firmware-mirror
              - ge,imp3a-paged-flash
              - gef,ppc9a-firmware-mirror
              - gef,ppc9a-paged-flash
              - gef,sbc310-firmware-mirror
              - gef,sbc310-paged-flash
              - gef,sbc610-firmware-mirror
              - gef,sbc610-paged-flash
              - intel,28f128j3
              - intel,dt28f160
              - intel,ixp4xx-flash
              - intel,JS28F128
              - intel,JS28F640
              - intel,PC28F640P30T85
              - numonyx,js28f00a
              - numonyx,js28f128
              - sst,sst39vf320
              - xlnx,xps-mch-emc-2.00.a
          - enum:
              - cfi-flash
              - jedec-flash
      - items:
          - enum:
              - cypress,cy7c1019dv33-10zsxi
              - arm,vexpress-psram
          - const: mtd-ram
      - enum:
          - cfi-flash
          - jedec-flash
          - mtd-ram
          - mtd-rom

  reg:
    description: |
      It's possible to (optionally) define multiple "reg" tuples so that
      non-identical chips can be described in one node.      
    minItems: 1
    maxItems: 8

  bank-width:
    description: Width (in bytes) of the bank.  Equal to the device width times
      the number of interleaved chips.
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 1, 2, 4 ]

  device-width:
    description:
      Width of a single mtd chip. If omitted, assumed to be equal to 'bank-width'.
    $ref: /schemas/types.yaml#/definitions/uint32
    enum: [ 1, 2 ]

  no-unaligned-direct-access:
    type: boolean
    description: |
      Disables the default direct mapping of the flash.

      On some platforms (e.g. MPC5200) a direct 1:1 mapping may cause problems
      with JFFS2 usage, as the local bus (LPB) doesn't support unaligned
      accesses as implemented in the JFFS2 code via memcpy(). By defining
      "no-unaligned-direct-access", the flash will not be exposed directly to
      the MTD users (e.g. JFFS2) any more.      

  linux,mtd-name:
    description:
      Allows specifying the mtd name for retro capability with physmap-flash
      drivers as boot loader pass the mtd partition via the old device name
      physmap-flash.
    $ref: /schemas/types.yaml#/definitions/string

  use-advanced-sector-protection:
    type: boolean
    description: |
      Enables support for the advanced sector protection (Spansion: PPB -
      Persistent Protection Bits) locking.      

  erase-size:
    description: The chip's physical erase block size in bytes.
    $ref: /schemas/types.yaml#/definitions/uint32

  addr-gpios:
    description:
      List of GPIO descriptors that will be used to address the MSBs address
      lines. The order goes from LSB to MSB.
    minItems: 1
    maxItems: 8

  '#address-cells':
    const: 1

  '#size-cells':
    const: 1

  big-endian: true
  little-endian: true

patternProperties:
  '@[0-9a-f]+$':
    $ref: partitions/partition.yaml

required:
  - compatible
  - reg

if:
  properties:
    compatible:
      contains:
        const: cortina,gemini-flash
then:
  properties:
    syscon:
      $ref: /schemas/types.yaml#/definitions/phandle
      description:
        Phandle to the syscon controller
  required:
    - syscon

# FIXME: A parent bus may define timing properties
additionalProperties: true

examples:
  - |

    flash@ff000000 {
        compatible = "cfi-flash";
        reg = <0xff000000 0x01000000>;
        bank-width = <4>;
        device-width = <1>;

        #address-cells = <1>;
        #size-cells = <1>;
        ranges = <0 0xff000000 0x01000000>;

        fs@0 {
            label = "fs";
            reg = <0 0xf80000>;
        };
        firmware@f80000 {
            label ="firmware";
            reg = <0xf80000 0x80000>;
            read-only;
        };
    };

  - |
    /* An example with multiple "reg" tuples */

    flash@0 {
        compatible = "intel,PC28F640P30T85", "cfi-flash";
        reg = <0x00000000 0x02000000>,
              <0x02000000 0x02000000>;
        bank-width = <2>;

        #address-cells = <1>;
        #size-cells = <1>;
        ranges = <0 0 0x04000000>;

        partition@0 {
            label = "test-part1";
            reg = <0 0x04000000>;
        };
    };    

  - |
    /* An example using SRAM */
    bus {
        #address-cells = <2>;
        #size-cells = <1>;

        sram@2,0 {
            compatible = "mtd-ram";
            reg = <2 0 0x00200000>;
            bank-width = <2>;
        };
    };    

  - |
    /* An example using addr-gpios */
    #include <dt-bindings/gpio/gpio.h>

    flash@20000000 {
        compatible = "cfi-flash";
        reg = <0x20000000 0x02000000>;
        bank-width = <2>;
        addr-gpios = <&gpio1 2 GPIO_ACTIVE_HIGH>;

        #address-cells = <1>;
        #size-cells = <1>;
        ranges = <0 0x00000000 0x02000000>,
                 <1 0x02000000 0x02000000>;

        partition@0 {
            label = "test-part1";
            reg = <0 0x04000000>;
        };
    };    
...