Add stub interface for MPAS dynamical core

The APIs between CAM-SIMA control and dynamical core have changed from CAM.

This stub interface currently does nothing, but it provides a fresh start from
scratch for actual functionalities to be incrementally implemented later.

src/dynamics/mpas/dyn_comp.F90

@@ -0,0 +1,42 @@
+module dyn_comp
+    use runtime_obj, only: runtime_options
+
+    implicit none
+
+    private
+    ! Provide APIs required by CAM Control.
+    public :: dyn_import_t
+    public :: dyn_export_t
+    public :: dyn_readnl
+    public :: dyn_init
+    ! public :: dyn_run
+    ! public :: dyn_final
+
+    type dyn_import_t
+    end type dyn_import_t
+
+    type dyn_export_t
+    end type dyn_export_t
+contains
+
+! Called by `read_namelist` in `src/control/runtime_opts.F90`.
+subroutine dyn_readnl(namelist_path)
+    character(*), intent(in) :: namelist_path
+end subroutine dyn_readnl
+
+! Called by `cam_init` in `src/control/cam_comp.F90`.
+subroutine dyn_init(cam_runtime_opts, dyn_in, dyn_out)
+    type(runtime_options), intent(in)  :: cam_runtime_opts
+    type(dyn_import_t),    intent(out) :: dyn_in
+    type(dyn_export_t),    intent(out) :: dyn_out
+end subroutine dyn_init
+
+! Not used for now. Intended to be called by `stepon_run*` in `src/dynamics/mpas/stepon.F90`.
+! subroutine dyn_run()
+! end subroutine dyn_run
+
+! Not used for now. Intended to be called by `stepon_final` in `src/dynamics/mpas/stepon.F90`.
+! subroutine dyn_final()
+! end subroutine dyn_final
+
+end module dyn_comp

src/dynamics/mpas/dyn_grid.F90

@@ -0,0 +1,13 @@
+module dyn_grid
+    implicit none
+
+    private
+    ! Provide APIs required by CAM Control.
+    public :: model_grid_init
+contains
+
+! Called by `cam_init` in `src/control/cam_comp.F90`.
+subroutine model_grid_init()
+end subroutine model_grid_init
+
+end module dyn_grid

src/dynamics/mpas/stepon.F90

@@ -0,0 +1,62 @@
+module stepon
+    use camsrfexch,    only: cam_out_t
+    use dyn_comp,      only: dyn_import_t, dyn_export_t
+    use physics_types, only: physics_state, physics_tend
+    use runtime_obj,   only: runtime_options
+    use shr_kind_mod,  only: r8 => shr_kind_r8
+
+    implicit none
+
+    private
+    ! Provide APIs required by CAM Control.
+    public :: stepon_init
+    public :: stepon_run1
+    public :: stepon_run2
+    public :: stepon_run3
+    public :: stepon_final
+contains
+
+! Called by `cam_init` in `src/control/cam_comp.F90`.
+subroutine stepon_init(cam_runtime_opts, dyn_in, dyn_out)
+    type(runtime_options), intent(in) :: cam_runtime_opts
+    type(dyn_import_t),    intent(in) :: dyn_in
+    type(dyn_export_t),    intent(in) :: dyn_out
+end subroutine stepon_init
+
+! Called by `cam_run1` in `src/control/cam_comp.F90`.
+subroutine stepon_run1(dtime_phys, cam_runtime_opts, phys_state, phys_tend, dyn_in, dyn_out)
+    real(r8),              intent(out)   :: dtime_phys
+    type(runtime_options), intent(in)    :: cam_runtime_opts
+    type(physics_state),   intent(inout) :: phys_state
+    type(physics_tend),    intent(inout) :: phys_tend
+    type(dyn_import_t),    intent(inout) :: dyn_in
+    type(dyn_export_t),    intent(inout) :: dyn_out
+end subroutine stepon_run1
+
+! Called by `cam_run2` in `src/control/cam_comp.F90`.
+subroutine stepon_run2(cam_runtime_opts, phys_state, phys_tend, dyn_in, dyn_out)
+    type(runtime_options), intent(in)    :: cam_runtime_opts
+    type(physics_state),   intent(inout) :: phys_state
+    type(physics_tend),    intent(inout) :: phys_tend
+    type(dyn_import_t),    intent(inout) :: dyn_in
+    type(dyn_export_t),    intent(inout) :: dyn_out
+end subroutine stepon_run2
+
+! Called by `cam_run3` in `src/control/cam_comp.F90`.
+subroutine stepon_run3(dtime_phys, cam_runtime_opts, cam_out, phys_state, dyn_in, dyn_out)
+    real(r8),              intent(in)    :: dtime_phys
+    type(runtime_options), intent(in)    :: cam_runtime_opts
+    type(cam_out_t),       intent(inout) :: cam_out
+    type(physics_state),   intent(inout) :: phys_state
+    type(dyn_import_t),    intent(inout) :: dyn_in
+    type(dyn_export_t),    intent(inout) :: dyn_out
+end subroutine stepon_run3
+
+! Called by `cam_final` in `src/control/cam_comp.F90`.
+subroutine stepon_final(cam_runtime_opts, dyn_in, dyn_out)
+    type(runtime_options), intent(in)    :: cam_runtime_opts
+    type(dyn_import_t),    intent(inout) :: dyn_in
+    type(dyn_export_t),    intent(inout) :: dyn_out
+end subroutine stepon_final
+
+end module stepon