Register Model Adaptor

Title: Classes for Adapting Between Register and Bus Operations

This section defines classes used to convert transaction streams between generic register address/data reads and writes and physical bus accesses.

Group: Example

The following example illustrates how to implement a RegModel-BUS adapter class for the APB bus protocol:

class rreg2apb_adapter(UVMRegAdapter):

    def __init__(self, name="reg2apb_adapter"):
        super().__init__(name)

    def reg2bus(self, rw) -> UVMSequenceItem:
        apb_item apb = apb_item.type_id.create("apb_item")
        apb.op   = (rw.kind == UVM_READ) ? apb.READ : apb.WRITE
        apb.addr = rw.addr
        apb.data = rw.data
        return apb

    def bus2reg(self, bus_item, rw) -> None:
        arr_apb = []
        if not sv.cast(arr_apb, bus_item, apb_item)) begin
          uvm_fatal("CONVERT_APB2REG","Bus item is not of type apb_item")
        end
        apb = arr_apb[0]

        rw.kind  = apb.op==apb.READ ? UVM_READ : UVM_WRITE
        rw.addr = apb.addr
        rw.data = apb.data
        rw.status = UVM_IS_OK

uvm_object_utils(reg2apb_adapter)

class uvm.reg.uvm_reg_adapter.UVMRegAdapter(name='')

Bases: UVMObject

Class: UVMRegAdapter

This class defines an interface for converting between <uvm_reg_bus_op> and a specific bus transaction.

Variables

supports_byte_enable (bool) –

Set this bit in extensions of this class if the bus protocol supports byte enables. Default is False.

Variables

provides_responses (bool) –

Set this bit in extensions of this class if the bus driver provides separate response items. Default is False.

Variables

parent_sequence (UVMSequenceBase) –

Set this member in extensions of this class if the bus driver requires bus items be executed via a particular sequence base type. The sequence assigned to this member must implement UVMObject.do_clone().

reg2bus(rw)

Function: reg2bus

Extensions of this class must implement this method to convert the specified uvm_reg_bus_op to a corresponding uvm_sequence_item subtype that defines the bus transaction.

The method must allocate a new bus-specific uvm_sequence_item, assign its members from the corresponding members from the given generic rw bus operation, then return it.

Parameters

rw –

Raises:

bus2reg(bus_item, rw)

Function: bus2reg

Extensions of this class must implement this method to copy members of the given bus-specific bus_item to corresponding members of the provided bus_rw instance. Unlike reg2bus, the resulting transaction is not allocated from scratch. This is to accommodate applications where the bus response must be returned in the original request.

pure virtual function void bus2reg(uvm_sequence_item bus_item,

ref uvm_reg_bus_op rw)

Parameters

• bus_item –

• rw –

Raises:

get_item()

m_set_item(item)

virtual function void m_set_item(uvm_reg_item item)

Parameters

item –