dts/bindings/mtd/atmel,sam-flash.yaml

# Copyright (c) 2023 Bjarki Arge Andreasen
# SPDX-License-Identifier: Apache-2.0

description: |
  This binding describes the Atmel SAM flash area layout.

  The Atmel SAM flash area varies in write-block-size, memory area,
  and the layout of erase-blocks.

  E.g. the flash area layout of the ATSAM4E16C:

    |--------------------|
    | 8 Kbytes           |  erase block size = 2048
    |--------------------|
    | 8 Kbytes           |  erase block size = 2048
    |--------------------|
    | 48 Kbytes          |  erase block size = 4096
    |--------------------|
    | 64 Kbytes          |  erase block size = 4096
    |--------------------|
    | ...                |

  The ATSAM4E16C has a flash area which is 1000Kbytes
  (1024 * 1024 bytes) with a write-block-size of 8 bytes. The first
  16 Kbytes can be erased in blocks of 2048 bytes
  (8 blocks of 2048 bytes), the remaining flash area is erasable
  in blocks of 4096 bytes (252 blocks of 4096 bytes).

  This flash area layout would described as:

    / {
      soc {
        eefc: flash-controller@400e0a00 {
        compatible = "atmel,sam-flash-controller";
        reg = <0x400e0a00 0x200>;
        clocks = <&pmc PMC_TYPE_PERIPHERAL 6>;
        status = "okay";

        #address-cells = <1>;
        #size-cells = <1>;
        #erase-block-cells = <2>;

        flash0: flash@400000 {
          compatible = "atmel,sam-flash", "soc-nv-flash";
          reg = <0x400000 0x100000>;
          write-block-size = <8>;
          erase-block-size = <4096>;
          erase-blocks = <&eefc 8 2048>, <&eefc 252 4096>;
        };
      };
    };

  Notes:
    The flash area layout node flash0 should have both this
    compatible, "atmel,sam-flash", and the "soc-nv-flash"
    compatible. The latter is used from mcuboot and other
    modules to identify the flash area.

    If partitions are used, remember that their addresses are
    offsets relative to the flash area address.  E.g. using
    mcuboot and a allocating a storage partition:

      &flash0 {
        partitions {
          compatible = "fixed-partitions";
          #address-cells = <1>;
          #size-cells = <1>;

          boot_partition: partition@0 {
            label = "mcuboot";
            reg = <0x0 0x10000>;
          };

          slot0_partition: partition@10000 {
            label = "slot0";
            reg = <0x10000 0x70000>;
          };

          slot1_partition: partition@80000 {
            label = "slot1";
            reg = <0x80000 0x70000>;
          };

          storage_partition: partition@f0000 {
            label = "storage";
            reg = <0xf0000 0x100000>;
          };
        };
      };

compatible: "atmel,sam-flash"

include: base.yaml

properties:
  write-block-size:
    type: int
    description: |
      The flash controller is limited by hardware to writing blocks of
      this size, aligned to this size, in bytes, to previously erased
      flash, within the flash memory area.

  erase-block-size:
    type: int
    description: |
      The flash controller is limited by hardware to erase whole
      blocks of flash at a time. This property describes the largest
      erase block size in erase-blocks.

  erase-blocks:
    type: phandle-array
    required: true
    description: |
      The flash controller is limited by hardware to erase whole
      blocks of flash at a time. This property describes the layout of
      the erase-blocks, which can vary in size within the flash memory
      area.