Devicetree integration

Sentry use Devicetree Specification for hardware description and configuration. Dts [1] file is preprocessed at build time and used to generate code according to configuration. Dts file dts include dir (for fragments and bindings resolution) have to be passed at project configure time, see Bootstraping Sentry build section.

[1]

Device Tree Source

CamelotOS/Sentry requires custom nodes and property to work as expected.

Properties

sentry,owner property

This property is an u32 type property used to assign the owner task label to a the parent node. This property is mandatory for each mappable and/or restricted node as userspace devices, shared memories and dma buffers.

/{
  ...
  some_nodelabel: name@address {
      ...
      sentry,owner = <0xbabe>;
      ...
    };
};

chosen node

sentry,debug_stdout property

This property defines the device to use as standard output use in debug mode if configured. ..

Add a reference to config here

• type: phandle

• parent: chosen

/{
    chosen {
        sentry,debug_stdout = <&usart1>;
    }
};

sentry,kernelram_section property

Reference to the kernel ram reserved memory region.

• type: phandle

• parent: chosen

Note

This property is mandatory

sentry,idleram_section property

Reference to the idle task ram reserved memory region.

• type: phandle

• parent: chosen

Note

This property is mandatory

sentry,kernelcode_section property

Reference to the kernel code reserved memory region.

• type: phandle

• parent: chosen

Note

This property is mandatory

sentry,idlecode_section property

Reference to the idle task code reserved memory region.

• type: phandle

• parent: chosen

Note

This property is mandatory

sentry,autotestram_section property

Reference to the autotest task ram reserved memory region.

• type: phandle

• parent: chosen

Note

Required while build in autotest mode

sentry,autotestcode_section property

Reference to the autotest task code reserved memory region.

• type: phandle

• parent: chosen

Note

Required while build in autotest mode

sentry,rng property

TBD

reserved-memory node

reserved-memory is the node holding memory region reserved for a specific usage. This could be kernel, idle task or user tasks code/ram region, shared memory or, dma buffers. Each child node describe one region with the following properties:

• reg: <base_address size> (mandatory)

• dma-pool: boolean, this region can be used as dma-pool.

• sentry,shm: boolean, can be use as shared memory, this property requires sentry,label and sentry,owner property to be defined

• sentry,label: memory region label (used by user space to get internal opaque handler)

• sentry,owner: see sentry,owner property section.

• sentry,no-map: prevent region to be mapped by sentry kernel.

Important

[kernel/idle/autotest/tasks]_code/ram label are reserved and mandatory in order to declare, respectively, kernel, idle task, autotest task and user defined tasks memory region. autotest` and tasks are mutually exclusive as there is no user tasks in autotest mode. All user tasks are relocated at project build time in the configured region. For those regions, only reg property is required, all others are ignored.

Warning

reserved memory regions must comply with target MPU alignment requirements.

  reserved-memory {
      #address-cells = <1>;
      #size-cells = <1>;

      kernel_code: memory@8000000 {
          reg = <0x8000000 0x8000>;
          compatible = "sentry,memory-pool";
      };
      idle_code: memory@8008000 {
          reg = <0x8008000 0x300>;
          compatible = "sentry,memory-pool";
      };
      kernel_ram: memory@20000000 {
          reg = <0x20000000 0x2000>;
          compatible = "sentry,memory-pool";
      };
      idle_ram: memory@20004000 {
          reg = <0x20004000 0x200>;
          compatible = "sentry,memory-pool";
      };
      tasks_code: memory@0800a000 {
          reg = <0x0800a000 0x200000>;
          compatible = "sentry,memory-pool";
      };
      tasks_ram: memory@20008000 {
          reg = <0x20008000 0x280000>;
          compatible = "sentry,memory-pool";
      };
  };