xref: /openbmc/linux/Documentation/devicetree/bindings/dma/st,stm32-mdma.yaml (revision 10cafa2d)

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/dma/st,stm32-mdma.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: STMicroelectronics STM32 MDMA Controller

description: |
  The STM32 MDMA is a general-purpose direct memory access controller capable of
  supporting 64 independent DMA channels with 256 HW requests.
  DMA clients connected to the STM32 MDMA controller must use the format
  described in the dma.txt file, using a five-cell specifier for each channel:
  a phandle to the MDMA controller plus the following five integer cells:
    1. The request line number
    2. The priority level
      0x0: Low
      0x1: Medium
      0x2: High
      0x3: Very high
    3. A 32bit mask specifying the DMA channel configuration
      -bit 0-1: Source increment mode
        0x0: Source address pointer is fixed
        0x2: Source address pointer is incremented after each data transfer
        0x3: Source address pointer is decremented after each data transfer
      -bit 2-3: Destination increment mode
        0x0: Destination address pointer is fixed
        0x2: Destination address pointer is incremented after each data transfer
        0x3: Destination address pointer is decremented after each data transfer
      -bit 8-9: Source increment offset size
        0x0: byte (8bit)
        0x1: half-word (16bit)
        0x2: word (32bit)
        0x3: double-word (64bit)
      -bit 10-11: Destination increment offset size
        0x0: byte (8bit)
        0x1: half-word (16bit)
        0x2: word (32bit)
        0x3: double-word (64bit)
      -bit 25-18: The number of bytes to be transferred in a single transfer
                  (min = 1 byte, max = 128 bytes)
      -bit 29:28: Trigger Mode
        0x00: Each MDMA request triggers a buffer transfer (max 128 bytes)
        0x1: Each MDMA request triggers a block transfer (max 64K bytes)
        0x2: Each MDMA request triggers a repeated block transfer
        0x3: Each MDMA request triggers a linked list transfer
    4. A 32bit value specifying the register to be used to acknowledge the request
       if no HW ack signal is used by the MDMA client
    5. A 32bit mask specifying the value to be written to acknowledge the request
       if no HW ack signal is used by the MDMA client

maintainers:
  - Amelie Delaunay <amelie.delaunay@foss.st.com>

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

properties:
  "#dma-cells":
    const: 5

  compatible:
    const: st,stm32h7-mdma

  reg:
    maxItems: 1

  clocks:
    maxItems: 1

  interrupts:
    maxItems: 1

  resets:
    maxItems: 1

  st,ahb-addr-masks:
    $ref: /schemas/types.yaml#/definitions/uint32-array
    description: Array of u32 mask to list memory devices addressed via AHB bus.

required:
  - compatible
  - reg
  - clocks
  - interrupts

unevaluatedProperties: false

examples:
  - |
    #include <dt-bindings/interrupt-controller/arm-gic.h>
    #include <dt-bindings/clock/stm32mp1-clks.h>
    #include <dt-bindings/reset/stm32mp1-resets.h>
    dma-controller@52000000 {
      compatible = "st,stm32h7-mdma";
      reg = <0x52000000 0x1000>;
      interrupts = <122>;
      clocks = <&timer_clk>;
      resets = <&rcc 992>;
      #dma-cells = <5>;
      dma-channels = <16>;
      dma-requests = <32>;
      st,ahb-addr-masks = <0x20000000>, <0x00000000>;
    };

...