# Copyright (c) 2012 ARM Limited
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# Authors: Andreas Sandberg

from abc import ABCMeta, abstractmethod
import m5
from m5.objects import *
from m5.proxy import *
m5.util.addToPath('../configs/common')
import FSConfig
from Caches import *

class BaseSystem(object):
    """Base system builder.

    This class provides some basic functionality for creating an ARM
    system with the usual peripherals (caches, GIC, etc.). It allows
    customization by defining separate methods for different parts of
    the initialization process.
    """

    __metaclass__ = ABCMeta

    def __init__(self, mem_mode='timing', cpu_class=TimingSimpleCPU,
                 num_cpus=1, checker=False):
        """Initialize a simple ARM system.

        Keyword Arguments:
          mem_mode -- String describing the memory mode (timing or atomic)
          cpu_class -- CPU class to use
          num_cpus -- Number of CPUs to instantiate
          checker -- Set to True to add checker CPUs
        """
        self.mem_mode = mem_mode
        self.cpu_class = cpu_class
        self.num_cpus = num_cpus
        self.checker = checker

    def create_cpus(self):
        """Return a list of CPU objects to add to a system."""
        cpus = [ self.cpu_class(cpu_id=i, clock='2GHz')
                 for i in range(self.num_cpus) ]
        if self.checker:
            for c in cpus:
                c.addCheckerCpu()
        return cpus

    def create_caches_private(self, cpu):
        """Add private caches to a CPU.

        Arguments:
          cpu -- CPU instance to work on.
        """
        cpu.addPrivateSplitL1Caches(L1Cache(size='32kB', assoc=1),
                                    L1Cache(size='32kB', assoc=4))

    def create_caches_shared(self, system):
        """Add shared caches to a system.

        Arguments:
          system -- System to work on.

        Returns:
          A bus that CPUs should use to connect to the shared cache.
        """
        system.toL2Bus = CoherentBus(clock='2GHz')
        system.l2c = L2Cache(clock='2GHz', size='4MB', assoc=8)
        system.l2c.cpu_side = system.toL2Bus.master
        system.l2c.mem_side = system.membus.slave
        return system.toL2Bus

    def init_cpu(self, system, cpu):
        """Initialize a CPU.

        Arguments:
          system -- System to work on.
          cpu -- CPU to initialize.
        """
        cpu.createInterruptController()

    def init_system(self, system):
        """Initialize a system.

        Arguments:
          system -- System to initialize.
        """
        system.cpu = self.create_cpus()

        sha_bus = self.create_caches_shared(system)
        for cpu in system.cpu:
            if not cpu.switched_out:
                self.create_caches_private(cpu)
                self.init_cpu(system, cpu)
                cpu.connectAllPorts(sha_bus if sha_bus != None else system.membus,
                                    system.membus)
            else:
                self.init_cpu(system, cpu)

    @abstractmethod
    def create_system(self):
        """Create an return an initialized system."""
        pass

    @abstractmethod
    def create_root(self):
        """Create and return a simulation root using the system
        defined by this class."""
        pass

class BaseFSSystem(BaseSystem):
    """Basic full system builder."""

    def __init__(self, **kwargs):
        BaseSystem.__init__(self, **kwargs)

    def init_system(self, system):
        BaseSystem.init_system(self, system)

        #create the iocache
        system.iocache = IOCache(clock='1GHz', addr_ranges=system.mem_ranges)
        system.iocache.cpu_side = system.iobus.master
        system.iocache.mem_side = system.membus.slave

    def create_root(self):
        system = self.create_system()
        m5.ticks.setGlobalFrequency('1THz')
        return Root(full_system=True, system=system)

class BaseFSSystemUniprocessor(BaseFSSystem):
    """Basic full system builder for uniprocessor systems.

    Note: This class is only really needed to provide backwards
    compatibility in existing test cases.
    """

    def __init__(self, **kwargs):
        BaseFSSystem.__init__(self, **kwargs)

    def create_caches_private(self, cpu):
        cpu.addTwoLevelCacheHierarchy(L1Cache(size='32kB', assoc=1),
                                      L1Cache(size='32kB', assoc=4),
                                      L2Cache(size='4MB', assoc=8))

    def create_caches_shared(self, system):
        return None

class BaseFSSwitcheroo(BaseFSSystem):
    """Uniprocessor system prepared for CPU switching"""

    def __init__(self, cpu_classes, **kwargs):
        BaseFSSystem.__init__(self, **kwargs)
        self.cpu_classes = tuple(cpu_classes)

    def create_cpus(self):
        cpus = [ cclass(cpu_id=0, clock='2GHz', switched_out=True)
                 for cclass in self.cpu_classes ]
        cpus[0].switched_out = False
        return cpus