dt-bindings: arm: l2x0: Convert L2 cache to json-schema

* ARM L2 Cache Controller

ARM cores often have a separate L2C210/L2C220/L2C310 (also known as PL210/PL220/

PL310 and variants) based level 2 cache controller. All these various implementations

of the L2 cache controller have compatible programming models (Note 1).

Some of the properties that are just prefixed "cache-*" are taken from section

3.7.3 of the Devicetree Specification which can be found at:

https://www.devicetree.org/specifications/

The ARM L2 cache representation in the device tree should be done as follows:

Required properties:

- compatible : should be one of:

  "arm,pl310-cache"

  "arm,l220-cache"

  "arm,l210-cache"

  "bcm,bcm11351-a2-pl310-cache": DEPRECATED by "brcm,bcm11351-a2-pl310-cache"

  "brcm,bcm11351-a2-pl310-cache": For Broadcom bcm11351 chipset where an

     offset needs to be added to the address before passing down to the L2

     cache controller

  "marvell,aurora-system-cache": Marvell Controller designed to be

     compatible with the ARM one, with system cache mode (meaning

     maintenance operations on L1 are broadcasted to the L2 and L2

     performs the same operation).

  "marvell,aurora-outer-cache": Marvell Controller designed to be

     compatible with the ARM one with outer cache mode.

  "marvell,tauros3-cache": Marvell Tauros3 cache controller, compatible

     with arm,pl310-cache controller.

- cache-unified : Specifies the cache is a unified cache.

- cache-level : Should be set to 2 for a level 2 cache.

- reg : Physical base address and size of cache controller's memory mapped

  registers.

Optional properties:

- arm,data-latency : Cycles of latency for Data RAM accesses. Specifies 3 cells of

  read, write and setup latencies. Minimum valid values are 1. Controllers

  without setup latency control should use a value of 0.

- arm,tag-latency : Cycles of latency for Tag RAM accesses. Specifies 3 cells of

  read, write and setup latencies. Controllers without setup latency control

  should use 0. Controllers without separate read and write Tag RAM latency

  values should only use the first cell.

- arm,dirty-latency : Cycles of latency for Dirty RAMs. This is a single cell.

- arm,filter-ranges : <start length> Starting address and length of window to

  filter. Addresses in the filter window are directed to the M1 port. Other

  addresses will go to the M0 port.

- arm,io-coherent : indicates that the system is operating in an hardware

  I/O coherent mode. Valid only when the arm,pl310-cache compatible

  string is used.

- interrupts : 1 combined interrupt.

- cache-size : specifies the size in bytes of the cache

- cache-sets : specifies the number of associativity sets of the cache

- cache-block-size : specifies the size in bytes of a cache block

- cache-line-size : specifies the size in bytes of a line in the cache,

  if this is not specified, the line size is assumed to be equal to the

  cache block size

- cache-id-part: cache id part number to be used if it is not present

  on hardware

- wt-override: If present then L2 is forced to Write through mode

- arm,double-linefill : Override double linefill enable setting. Enable if

  non-zero, disable if zero.

- arm,double-linefill-incr : Override double linefill on INCR read. Enable

  if non-zero, disable if zero.

- arm,double-linefill-wrap : Override double linefill on WRAP read. Enable

  if non-zero, disable if zero.

- arm,prefetch-drop : Override prefetch drop enable setting. Enable if non-zero,

  disable if zero.

- arm,prefetch-offset : Override prefetch offset value. Valid values are

  0-7, 15, 23, and 31.

- arm,shared-override : The default behavior of the L220 or PL310 cache

  controllers with respect to the shareable attribute is to transform "normal

  memory non-cacheable transactions" into "cacheable no allocate" (for reads)

  or "write through no write allocate" (for writes).

  On systems where this may cause DMA buffer corruption, this property must be

  specified to indicate that such transforms are precluded.

- arm,parity-enable : enable parity checking on the L2 cache (L220 or PL310).

- arm,parity-disable : disable parity checking on the L2 cache (L220 or PL310).

- arm,outer-sync-disable : disable the outer sync operation on the L2 cache.

  Some core tiles, especially ARM PB11MPCore have a faulty L220 cache that

  will randomly hang unless outer sync operations are disabled.

- prefetch-data : Data prefetch. Value: <0> (forcibly disable), <1>

  (forcibly enable), property absent (retain settings set by firmware)

- prefetch-instr : Instruction prefetch. Value: <0> (forcibly disable),

  <1> (forcibly enable), property absent (retain settings set by

  firmware)

- arm,dynamic-clock-gating : L2 dynamic clock gating. Value: <0> (forcibly

  disable), <1> (forcibly enable), property absent (OS specific behavior,

  preferably retain firmware settings)

- arm,standby-mode: L2 standby mode enable. Value <0> (forcibly disable),

  <1> (forcibly enable), property absent (OS specific behavior,

  preferably retain firmware settings)

- arm,early-bresp-disable : Disable the CA9 optimization Early BRESP (PL310)

- arm,full-line-zero-disable : Disable the CA9 optimization Full line of zero

  write (PL310)

Example:

L2: cache-controller {

        compatible = "arm,pl310-cache";

        reg = <0xfff12000 0x1000>;

        arm,data-latency = <1 1 1>;

        arm,tag-latency = <2 2 2>;

        arm,filter-ranges = <0x80000000 0x8000000>;

        cache-unified;

        cache-level = <2>;

	interrupts = <45>;

};

Note 1: The description in this document doesn't apply to integrated L2

	cache controllers as found in e.g. Cortex-A15/A7/A57/A53. These

	integrated L2 controllers are assumed to be all preconfigured by

	early secure boot code. Thus no need to deal with their configuration

	in the kernel at all.

# SPDX-License-Identifier: GPL-2.0

%YAML 1.2

---

$id: http://devicetree.org/schemas/arm/l2c2x0.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#

title: ARM L2 Cache Controller

maintainers:

  - Rob Herring <robh@kernel.org>

description: |+

  ARM cores often have a separate L2C210/L2C220/L2C310 (also known as PL210/

  PL220/PL310 and variants) based level 2 cache controller. All these various

  implementations of the L2 cache controller have compatible programming

  models (Note 1). Some of the properties that are just prefixed "cache-*" are

  taken from section 3.7.3 of the Devicetree Specification which can be found

  at:

  https://www.devicetree.org/specifications/

  Note 1: The description in this document doesn't apply to integrated L2

    cache controllers as found in e.g. Cortex-A15/A7/A57/A53. These

    integrated L2 controllers are assumed to be all preconfigured by

    early secure boot code. Thus no need to deal with their configuration

    in the kernel at all.

allOf:

  - $ref: /schemas/cache-controller.yaml#

properties:

  compatible:

    enum:

      - arm,pl310-cache

      - arm,l220-cache

      - arm,l210-cache

        # DEPRECATED by "brcm,bcm11351-a2-pl310-cache"

      - bcm,bcm11351-a2-pl310-cache

        # For Broadcom bcm11351 chipset where an

        # offset needs to be added to the address before passing down to the L2

        # cache controller

      - brcm,bcm11351-a2-pl310-cache

        # Marvell Controller designed to be

        # compatible with the ARM one, with system cache mode (meaning

        # maintenance operations on L1 are broadcasted to the L2 and L2

        # performs the same operation).

      - marvell,aurora-system-cache

        # Marvell Controller designed to be

        # compatible with the ARM one with outer cache mode.

      - marvell,aurora-outer-cache

        # Marvell Tauros3 cache controller, compatible

        # with arm,pl310-cache controller.

      - marvell,tauros3-cache

  cache-level:

    const: 2

  cache-unified: true

  cache-size: true

  cache-sets: true

  cache-block-size: true

  cache-line-size: true

  reg:

    maxItems: 1

  arm,data-latency:

    description: Cycles of latency for Data RAM accesses. Specifies 3 cells of

      read, write and setup latencies. Minimum valid values are 1. Controllers

      without setup latency control should use a value of 0.

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32-array

      - minItems: 2

        maxItems: 3

        items:

          minimum: 0

          maximum: 8

  arm,tag-latency:

    description: Cycles of latency for Tag RAM accesses. Specifies 3 cells of

      read, write and setup latencies. Controllers without setup latency control

      should use 0. Controllers without separate read and write Tag RAM latency

      values should only use the first cell.

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32-array

      - minItems: 1

        maxItems: 3

        items:

          minimum: 0

          maximum: 8

  arm,dirty-latency:

    description: Cycles of latency for Dirty RAMs. This is a single cell.

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - minimum: 1

        maximum: 8

  arm,filter-ranges:

    description: <start length> Starting address and length of window to

      filter. Addresses in the filter window are directed to the M1 port. Other

      addresses will go to the M0 port.

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32-array

      - items:

          minItems: 2

          maxItems: 2

  arm,io-coherent:

    description: indicates that the system is operating in an hardware

      I/O coherent mode. Valid only when the arm,pl310-cache compatible

      string is used.

    type: boolean

  interrupts:

    # Either a single combined interrupt or up to 9 individual interrupts

    minItems: 1

    maxItems: 9

  cache-id-part:

    description: cache id part number to be used if it is not present

      on hardware

    $ref: /schemas/types.yaml#/definitions/uint32

  wt-override:

    description: If present then L2 is forced to Write through mode

    type: boolean

  arm,double-linefill:

    description: Override double linefill enable setting. Enable if

      non-zero, disable if zero.

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - enum: [ 0, 1 ]

  arm,double-linefill-incr:

    description: Override double linefill on INCR read. Enable

      if non-zero, disable if zero.

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - enum: [ 0, 1 ]

  arm,double-linefill-wrap:

    description: Override double linefill on WRAP read. Enable

      if non-zero, disable if zero.

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - enum: [ 0, 1 ]

  arm,prefetch-drop:

    description: Override prefetch drop enable setting. Enable if non-zero,

      disable if zero.

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - enum: [ 0, 1 ]

  arm,prefetch-offset:

    description: Override prefetch offset value.

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - enum: [ 0, 1, 2, 3, 4, 5, 6, 7, 15, 23, 31 ]

  arm,shared-override:

    description: The default behavior of the L220 or PL310 cache

      controllers with respect to the shareable attribute is to transform "normal

      memory non-cacheable transactions" into "cacheable no allocate" (for reads)

      or "write through no write allocate" (for writes).

      On systems where this may cause DMA buffer corruption, this property must

      be specified to indicate that such transforms are precluded.

    type: boolean

  arm,parity-enable:

    description: enable parity checking on the L2 cache (L220 or PL310).

    type: boolean

  arm,parity-disable:

    description: disable parity checking on the L2 cache (L220 or PL310).

    type: boolean

  arm,outer-sync-disable:

    description: disable the outer sync operation on the L2 cache.

      Some core tiles, especially ARM PB11MPCore have a faulty L220 cache that

      will randomly hang unless outer sync operations are disabled.

    type: boolean

  prefetch-data:

    description: |

      Data prefetch. Value: <0> (forcibly disable), <1>

      (forcibly enable), property absent (retain settings set by firmware)

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - enum: [ 0, 1 ]

  prefetch-instr:

    description: |

      Instruction prefetch. Value: <0> (forcibly disable),

      <1> (forcibly enable), property absent (retain settings set by

      firmware)

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - enum: [ 0, 1 ]

  arm,dynamic-clock-gating:

    description: |

      L2 dynamic clock gating. Value: <0> (forcibly

      disable), <1> (forcibly enable), property absent (OS specific behavior,

      preferably retain firmware settings)

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - enum: [ 0, 1 ]

  arm,standby-mode:

    description: L2 standby mode enable. Value <0> (forcibly disable),

      <1> (forcibly enable), property absent (OS specific behavior,

      preferably retain firmware settings)

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - enum: [ 0, 1 ]

  arm,early-bresp-disable:

    description: Disable the CA9 optimization Early BRESP (PL310)

    type: boolean

  arm,full-line-zero-disable:

    description: Disable the CA9 optimization Full line of zero

      write (PL310)

    type: boolean

required:

  - compatible

  - cache-unified

  - reg

additionalProperties: false

examples:

  - |

    cache-controller@fff12000 {

        compatible = "arm,pl310-cache";

        reg = <0xfff12000 0x1000>;

        arm,data-latency = <1 1 1>;

        arm,tag-latency = <2 2 2>;

        arm,filter-ranges = <0x80000000 0x8000000>;

        cache-unified;

        cache-level = <2>;

        interrupts = <45>;

    };

...