xref: /linux/Documentation/devicetree/bindings/memory-controllers/qcom,ebi2-peripheral-props.yaml (revision bbfd5594756011167b8f8de9a00e0c946afda1e6)

# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/memory-controllers/qcom,ebi2-peripheral-props.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Peripheral Properties for Qualcomm External Bus Interface 2 (EBI2)

maintainers:
  - Bjorn Andersson <andersson@kernel.org>

properties:
  # SLOW chip selects
  qcom,xmem-recovery-cycles:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: >
      The time the memory continues to drive the data bus after OE
      is de-asserted, in order to avoid contention on the data bus.
      They are inserted when reading one CS and switching to another
      CS or read followed by write on the same CS. Minimum value is
      actually 1, so a value of 0 will still yield 1 recovery cycle.
    minimum: 0
    maximum: 15

  qcom,xmem-write-hold-cycles:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: >
      The extra cycles inserted after every write minimum 1. The
      data out is driven from the time WE is asserted until CS is
      asserted. With a hold of 1 (value = 0), the CS stays active
      for 1 extra cycle, etc.
    minimum: 0
    maximum: 15

  qcom,xmem-write-delta-cycles:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: >
      The initial latency for write cycles inserted for the first
      write to a page or burst memory.
    minimum: 0
    maximum: 255

  qcom,xmem-read-delta-cycles:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: >
      The initial latency for read cycles inserted for the first
      read to a page or burst memory.
    minimum: 0
    maximum: 255

  qcom,xmem-write-wait-cycles:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: >
      The number of wait cycles for every write access.
    minimum: 0
    maximum: 15

  qcom,xmem-read-wait-cycles:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: >
      The number of wait cycles for every read access.
    minimum: 0
    maximum: 15


  # FAST chip selects
  qcom,xmem-address-hold-enable:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: >
      Holds the address for an extra cycle to meet hold time
      requirements with ADV assertion, when set to 1.
    enum: [ 0, 1 ]

  qcom,xmem-adv-to-oe-recovery-cycles:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: >
      The number of cycles elapsed before an OE assertion, with
      respect to the cycle where ADV (address valid) is asserted.
    minimum: 0
    maximum: 3

  qcom,xmem-read-hold-cycles:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: >
      The length in cycles of the first segment of a read transfer.
      For a single read transfer this will be the time from CS
      assertion to OE assertion.
    minimum: 0
    maximum: 15

additionalProperties: true