TLM Generic Payload & Extensions

TLM Generic Payload & Extensions

The Generic Payload transaction represents a generic bus read/write access. It is used as the default transaction in TLM2 blocking and nonblocking transport interfaces.

class uvm.tlm2.uvm_tlm2_generic_payload.uvm_tlm_command_e(value)

Bases: Enum

Enum uvm_tlm_command_e Command attribute type definition

UVM_TLM_READ_COMMAND - Bus read operation

UVM_TLM_WRITE_COMMAND - Bus write operation

UVM_TLM_IGNORE_COMMAND - No bus operation.

UVM_TLM_READ_COMMAND = 1

UVM_TLM_WRITE_COMMAND = 2

UVM_TLM_IGNORE_COMMAND = 3

class uvm.tlm2.uvm_tlm2_generic_payload.uvm_tlm_response_status_e(value)

Bases: IntEnum

Enum uvm_tlm_response_status_e Response status attribute type definition

UVM_TLM_OK_RESPONSE - Bus operation completed successfully

UVM_TLM_INCOMPLETE_RESPONSE - Transaction was not delivered to target

UVM_TLM_GENERIC_ERROR_RESPONSE - Bus operation had an error

UVM_TLM_ADDRESS_ERROR_RESPONSE - Invalid address specified

UVM_TLM_COMMAND_ERROR_RESPONSE - Invalid command specified

UVM_TLM_BURST_ERROR_RESPONSE - Invalid burst specified

UVM_TLM_BYTE_ENABLE_ERROR_RESPONSE - Invalid byte enabling specified

OK_RESPONSE = 1

INCOMPLETE_RESPONSE = 0

GENERIC_ERROR_RESPONSE = -1

ADDRESS_ERROR_RESPONSE = -2

COMMAND_ERROR_RESPONSE = -3

BURST_ERROR_RESPONSE = -4

BYTE_ENABLE_ERROR_RESPONSE = -5

class uvm.tlm2.uvm_tlm2_generic_payload.UVMTLMGenericPayload(name='')

Bases: UVMSequenceItem

This class provides a transaction definition commonly used in memory-mapped bus-based systems. It’s intended to be a general purpose transaction class that lends itself to many applications. The class is derived from uvm_sequence_item which enables it to be generated in sequences and transported to drivers through sequencers.

Variables

m_address (int) –

Address for the bus operation. Should be set or read using the <set_address> and <get_address> methods. The variable should be used only when constraining.

For a read command or a write command, the target shall interpret the current value of the address attribute as the start address in the system memory map of the contiguous block of data being read or written. The address associated with any given byte in the data array is dependent upon the address attribute, the array index, the streaming width attribute, the endianness and the width of the physical bus.

If the target is unable to execute the transaction with the given address attribute (because the address is out-of-range, for example) it shall generate a standard error response. The recommended response status is ~UVM_TLM_ADDRESS_ERROR_RESPONSE~.

convert2string()

This virtual function is a user-definable hook, called directly by the user, that allows users to provide object information in the form of a string. Unlike sprint, there is no requirement to use a uvm_printer policy object. As such, the format and content of the output is fully customizable, which may be suitable for applications not requiring the consistent formatting offered by the print/sprint/do_print API.

Fields declared in <Utility Macros> macros (`uvm_field_*), if used, will not automatically appear in calls to convert2string.

An example implementation of convert2string follows.

 class Base(UVMObject):
   field = "foo"
   def convert2string(self):
     return "base_field=" + self.field

 class Obj2(UVMObject):
   field = "bar"
   def convert2string()
     convert2string = "child_field=" + self.field

 class Obj(Base):
   addr = 0x123
   data = 0x456
   write = 1
   child = Obj2()
   def convert2string(self):
      convert2string = super().convert2string() +
        sv.sformatf(" write=%0d addr=%8h data=%8h ",write,addr,data) +
        child.convert2string()

Then, to display an object, you could write:

.. code-block:: python

  o = Obj()
  uvm_report_info("BusMaster", "Sending:

” + o.convert2string())

The output will look similar to:

UVM_INFO @ 0: reporter [BusMaster] Sending:
  base_field=foo write=1 addr=00000123 data=00000456 child_field=bar

Returns:

str: Object converted into string.

get_command()

set_command(command)

is_read()

set_read()

is_write()

set_write()

set_address(addr)

get_address()

create(name='')

Group: Creation

The create method allocates a new object of the same type as this object and returns it via a base uvm_object handle. Every class deriving from uvm_object, directly or indirectly, must implement the create method.

A typical implementation is as follows:

class mytype (UVMObject):
  ...
  def create(self, name=""):
    mytype t = mytype(name)
    return t

Parameters

name (str) – Name of the created object.

Returns

New object.

Return type

obj

get_object_type()

Function: get_object_type

Returns the type-proxy (wrapper) for this object. The uvm_factory’s type-based override and creation methods take arguments of uvm_object_wrapper. This method, if implemented, can be used as convenient means of supplying those arguments. This method is the same as the static get_type method, but uses an already allocated object to determine the type-proxy to access (instead of using the static object).

The default implementation of this method does a factory lookup of the proxy using the return value from get_type_name. If the type returned by get_type_name is not registered with the factory, then a None handle is returned.

For example:

class cmd (UVMObject):
  type_id = UVMObjectRegistry()
  @classmethod
  def type_id get_type(cls):
    return type_id.get()
  def get_object_type(self):
    return cmd.type_id.get()

This function is implemented by the `uvm_*_utils macros, if employed.

Returns:

classmethod get_type()

Returns the type-proxy (wrapper) for this object. The UVMFactory’s type-based override and creation methods take arguments of uvm_object_wrapper. This method, if implemented, can be used as convenient means of supplying those arguments.

The default implementation of this method produces an error and returns None. To enable use of this method, a user’s subtype must implement a version that returns the subtype’s wrapper.

For example:

class cmd(UVMObject):
  type_id = None

  @classmethod
  def get_type(cls):
    return cls.type_id.get()

Then, to use:

factory.set_type_override(cmd.get_type(), subcmd.get_type())

This function is implemented by the uvm_*_utils functions, if employed.

Returns:

get_type_name()

This function returns the type name of the object, which is typically the type identifier enclosed in quotes. It is used for various debugging functions in the library, and it is used by the factory for creating objects.

This function must be defined in every derived class.

A typical implementation is as follows:

class mytype (UVMObject):
  ...
  type_name = "mytype"

  def get_type_name(self):
    return my_type.type_name

We define the type_name static variable to enable access to the type name without need of an object of the class, i.e., to enable access via the scope operator, ~mytype::type_name~.

Returns

Type name of the object.

Return type

str

type_id = <uvm.base.uvm_registry.UVMObjectRegistry object>

type_name = 'UVMTLMGenericPayload'

m_sequencer: Any

p_sequencer: Any

class uvm.tlm2.uvm_tlm2_generic_payload.UVMTLMExtensionBase(name='')

Bases: UVMObject

do_copy(rhs)

The do_copy method is the user-definable hook called by the copy method. A derived class should override this method to include its fields in a copy operation.

A typical implementation is as follows:

class mytype (UVMObject):
  ...
  field_1 = 0
  def do_copy(self, rhs):
    super.do_copy(rhs)
    # Optionanl type checking
    field_1 = rhs.field_1

The implementation must call super().do_copy, and can optionally do type checking before copying.

Parameters

rhs (UVMObject) – Object to be copied.

create(name='')

Group: Creation

The create method allocates a new object of the same type as this object and returns it via a base uvm_object handle. Every class deriving from uvm_object, directly or indirectly, must implement the create method.

A typical implementation is as follows:

class mytype (UVMObject):
  ...
  def create(self, name=""):
    mytype t = mytype(name)
    return t

Parameters

name (str) – Name of the created object.

Returns

New object.

Return type

obj

class uvm.tlm2.uvm_tlm2_generic_payload.UVMTLMExtension(name='')

Bases: UVMTLMExtensionBase