gem5/src/mem/Bus.py
Andreas Sandberg b904bd5437 sim: Add a system-global option to bypass caches
Virtualized CPUs and the fastmem mode of the atomic CPU require direct
access to physical memory. We currently require caches to be disabled
when using them to prevent chaos. This is not ideal when switching
between hardware virutalized CPUs and other CPU models as it would
require a configuration change on each switch. This changeset
introduces a new version of the atomic memory mode,
'atomic_noncaching', where memory accesses are inserted into the
memory system as atomic accesses, but bypass caches.

To make memory mode tests cleaner, the following methods are added to
the System class:

 * isAtomicMode() -- True if the memory mode is 'atomic' or 'direct'.
 * isTimingMode() -- True if the memory mode is 'timing'.
 * bypassCaches() -- True if caches should be bypassed.

The old getMemoryMode() and setMemoryMode() methods should never be
used from the C++ world anymore.
2013-02-15 17:40:09 -05:00

79 lines
3.6 KiB
Python

# Copyright (c) 2012 ARM Limited
# All rights reserved.
#
# The license below extends only to copyright in the software and shall
# not be construed as granting a license to any other intellectual
# property including but not limited to intellectual property relating
# to a hardware implementation of the functionality of the software
# licensed hereunder. You may use the software subject to the license
# terms below provided that you ensure that this notice is replicated
# unmodified and in its entirety in all distributions of the software,
# modified or unmodified, in source code or in binary form.
#
# Copyright (c) 2005-2008 The Regents of The University of Michigan
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution;
# neither the name of the copyright holders nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# Authors: Nathan Binkert
# Andreas Hansson
from MemObject import MemObject
from System import System
from m5.params import *
from m5.proxy import *
class BaseBus(MemObject):
type = 'BaseBus'
abstract = True
cxx_header = "mem/bus.hh"
slave = VectorSlavePort("vector port for connecting masters")
master = VectorMasterPort("vector port for connecting slaves")
header_cycles = Param.Cycles(1, "cycles of overhead per transaction")
width = Param.Unsigned(8, "bus width (bytes)")
block_size = Param.Unsigned(64, "The default block size if not set by " \
"any connected module")
# The default port can be left unconnected, or be used to connect
# a default slave port
default = MasterPort("Port for connecting an optional default slave")
# The default port can be used unconditionally, or based on
# address range, in which case it may overlap with other
# ports. The default range is always checked first, thus creating
# a two-level hierarchical lookup. This is useful e.g. for the PCI
# bus configuration.
use_default_range = Param.Bool(False, "Perform address mapping for " \
"the default port")
class NoncoherentBus(BaseBus):
type = 'NoncoherentBus'
cxx_header = "mem/noncoherent_bus.hh"
class CoherentBus(BaseBus):
type = 'CoherentBus'
cxx_header = "mem/coherent_bus.hh"
system = Param.System(Parent.any, "System that the bus belongs to.")