Documentation/devicetree/bindings/arm/stm32/st,mlahb.yaml

   1 # SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
   2 %YAML 1.2
   3 ---
   4 $id: "http://devicetree.org/schemas/arm/stm32/st,mlahb.yaml#"
   5 $schema: "http://devicetree.org/meta-schemas/core.yaml#"
   6
   7 title: STMicroelectronics STM32 ML-AHB interconnect bindings
   8
   9 maintainers:
  10   - Fabien Dessenne <fabien.dessenne@st.com>
  11   - Arnaud Pouliquen <arnaud.pouliquen@st.com>
  12
  13 description: |
  14   These bindings describe the STM32 SoCs ML-AHB interconnect bus which connects
  15   a Cortex-M subsystem with dedicated memories. The MCU SRAM and RETRAM memory
  16   parts can be accessed through different addresses (see "RAM aliases" in [1])
  17   using different buses (see [2]): balancing the Cortex-M firmware accesses
  18   among those ports allows to tune the system performance.
  19   [1]: https://www.st.com/resource/en/reference_manual/dm00327659.pdf
  20   [2]: https://wiki.st.com/stm32mpu/wiki/STM32MP15_RAM_mapping
  21
  22 allOf:
  23   - $ref: /schemas/simple-bus.yaml#
  24
  25 properties:
  26   compatible:
  27     contains:
  28       enum:
  29         - st,mlahb
  30
  31   dma-ranges:
  32     description: |
  33       Describe memory addresses translation between the local CPU and the
  34       remote Cortex-M processor. Each memory region, is declared with
  35       3 parameters:
  36       - param 1: device base address (Cortex-M processor address)
  37       - param 2: physical base address (local CPU address)
  38       - param 3: size of the memory region.
  39     maxItems: 3
  40
  41   '#address-cells':
  42     const: 1
  43
  44   '#size-cells':
  45     const: 1
  46
  47 required:
  48   - compatible
  49   - '#address-cells'
  50   - '#size-cells'
  51   - dma-ranges
  52
  53 unevaluatedProperties: false
  54
  55 examples:
  56   - |
  57     mlahb: ahb@38000000 {
  58       compatible = "st,mlahb", "simple-bus";
  59       #address-cells = <1>;
  60       #size-cells = <1>;
  61       reg = <0x10000000 0x40000>;
  62       ranges;
  63       dma-ranges = <0x00000000 0x38000000 0x10000>,
  64                    <0x10000000 0x10000000 0x60000>,
  65                    <0x30000000 0x30000000 0x60000>;
  66
  67       m4_rproc: m4@10000000 {
  68        reg = <0x10000000 0x40000>;
  69       };
  70     };
  71
  72 ...