Documentation/devicetree/bindings/dma/ti/k3-bcdma.yaml

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
# Copyright (C) 2020 Texas Instruments Incorporated
# Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
%YAML 1.2
---
$id: http://devicetree.org/schemas/dma/ti/k3-bcdma.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Texas Instruments K3 DMSS BCDMA Device Tree Bindings

maintainers:
  - Peter Ujfalusi <peter.ujfalusi@gmail.com>

description: |
  The Block Copy DMA (BCDMA) is intended to perform similar functions as the TR
  mode channels of K3 UDMA-P.
  BCDMA includes block copy channels and Split channels.

  Block copy channels mainly used for memory to memory transfers, but with
  optional triggers a block copy channel can service peripherals by accessing
  directly to memory mapped registers or area.

  Split channels can be used to service PSI-L based peripherals.
  The peripherals can be PSI-L native or legacy, non PSI-L native peripherals
  with PDMAs. PDMA is tasked to act as a bridge between the PSI-L fabric and the
  legacy peripheral.

  PDMAs can be configured via BCDMA split channel's peer registers to match with
  the configuration of the legacy peripheral.

allOf:
  - $ref: /schemas/dma/dma-controller.yaml#

properties:
  compatible:
    const: ti,am64-dmss-bcdma

  "#dma-cells":
    const: 3
    description: |
      cell 1: type of the BCDMA channel to be used to service the peripheral:
        0 - split channel
        1 - block copy channel using global trigger 1
        2 - block copy channel using global trigger 2
        3 - block copy channel using local trigger

      cell 2: parameter for the channel:
        if cell 1 is 0 (split channel):
          PSI-L thread ID of the remote (to BCDMA) end.
          Valid ranges for thread ID depends on the data movement direction:
          for source thread IDs (rx): 0 - 0x7fff
          for destination thread IDs (tx): 0x8000 - 0xffff

          Please refer to the device documentation for the PSI-L thread map and
          also the PSI-L peripheral chapter for the correct thread ID.
        if cell 1 is 1 or 2 (block copy channel using global trigger):
          Unused, ignored

          The trigger must be configured for the channel externally to BCDMA,
          channels using global triggers should not be requested directly, but
          via DMA event router.
        if cell 1 is 3 (block copy channel using local trigger):
          bchan number of the locally triggered channel

      cell 3: ASEL value for the channel

  reg:
    maxItems: 5

  reg-names:
    items:
      - const: gcfg
      - const: bchanrt
      - const: rchanrt
      - const: tchanrt
      - const: ringrt

  msi-parent: true

  ti,asel:
    $ref: /schemas/types.yaml#/definitions/uint32
    description: ASEL value for non slave channels

  ti,sci-rm-range-bchan:
    $ref: /schemas/types.yaml#/definitions/uint32-array
    description: |
      Array of BCDMA block-copy channel resource subtypes for resource
      allocation for this host
    minItems: 1
    # Should be enough
    maxItems: 255
    items:
      maximum: 0x3f

  ti,sci-rm-range-tchan:
    $ref: /schemas/types.yaml#/definitions/uint32-array
    description: |
      Array of BCDMA split tx channel resource subtypes for resource allocation
      for this host
    minItems: 1
    # Should be enough
    maxItems: 255
    items:
      maximum: 0x3f

  ti,sci-rm-range-rchan:
    $ref: /schemas/types.yaml#/definitions/uint32-array
    description: |
      Array of BCDMA split rx channel resource subtypes for resource allocation
      for this host
    minItems: 1
    # Should be enough
    maxItems: 255
    items:
      maximum: 0x3f

required:
  - compatible
  - "#dma-cells"
  - reg
  - reg-names
  - msi-parent
  - ti,sci
  - ti,sci-dev-id
  - ti,sci-rm-range-bchan
  - ti,sci-rm-range-tchan
  - ti,sci-rm-range-rchan

unevaluatedProperties: false

examples:
  - |+
    cbass_main {
        #address-cells = <2>;
        #size-cells = <2>;

        main_dmss {
            compatible = "simple-mfd";
            #address-cells = <2>;
            #size-cells = <2>;
            dma-ranges;
            ranges;

            ti,sci-dev-id = <25>;

            main_bcdma: dma-controller@485c0100 {
                compatible = "ti,am64-dmss-bcdma";

                reg = <0x0 0x485c0100 0x0 0x100>,
                      <0x0 0x4c000000 0x0 0x20000>,
                      <0x0 0x4a820000 0x0 0x20000>,
                      <0x0 0x4aa40000 0x0 0x20000>,
                      <0x0 0x4bc00000 0x0 0x100000>;
                reg-names = "gcfg", "bchanrt", "rchanrt", "tchanrt", "ringrt";
                msi-parent = <&inta_main_dmss>;
                #dma-cells = <3>;

                ti,sci = <&dmsc>;
                ti,sci-dev-id = <26>;

                ti,sci-rm-range-bchan = <0x20>; /* BLOCK_COPY_CHAN */
                ti,sci-rm-range-rchan = <0x21>; /* SPLIT_TR_RX_CHAN */
                ti,sci-rm-range-tchan = <0x22>; /* SPLIT_TR_TX_CHAN */
            };
        };
    };