# -*- coding: utf-8 -*-
# Copyright (c) 2016 Jason Lowe-Power
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# Authors: Jason Lowe-Power

""" Caches with options for a simple gem5 configuration script

This file contains L1 I/D and L2 caches to be used in the simple
gem5 configuration script. It uses the SimpleOpts wrapper to set up command
line options from each individual class.
"""

import m5
from m5.objects import Cache, L2XBar, StridePrefetcher, SubSystem
from m5.params import AddrRange, AllMemory, MemorySize
from m5.util.convert import toMemorySize

import SimpleOpts

# Some specific options for caches
# For all options see src/mem/cache/BaseCache.py

class PrefetchCache(Cache):

    SimpleOpts.add_option("--no_prefetchers", default=False,
                          action="store_true",
                          help="Enable prefectchers on the caches")

    def __init__(self, options):
        super(PrefetchCache, self).__init__()
        if not options or options.no_prefetchers:
            return
        self.prefetcher = StridePrefetcher()

class L1Cache(PrefetchCache):
    """Simple L1 Cache with default values"""

    assoc = 8
    tag_latency = 1
    data_latency = 1
    response_latency = 1
    mshrs = 16
    tgts_per_mshr = 20
    writeback_clean = True

    def __init__(self, options=None):
        super(L1Cache, self).__init__(options)
        pass

    def connectBus(self, bus):
        """Connect this cache to a memory-side bus"""
        self.mem_side = bus.slave

    def connectCPU(self, cpu):
        """Connect this cache's port to a CPU-side port
           This must be defined in a subclass"""
        raise NotImplementedError

class L1ICache(L1Cache):
    """Simple L1 instruction cache with default values"""

    # Set the default size
    size = '32kB'

    SimpleOpts.add_option('--l1i_size',
                        help="L1 instruction cache size. Default: %s" % size)

    def __init__(self, opts=None):
        super(L1ICache, self).__init__(opts)
        if not opts or not opts.l1i_size:
            return
        self.size = opts.l1i_size

    def connectCPU(self, cpu):
        """Connect this cache's port to a CPU icache port"""
        self.cpu_side = cpu.icache_port

class L1DCache(L1Cache):
    """Simple L1 data cache with default values"""

    # Set the default size
    size = '32kB'

    SimpleOpts.add_option('--l1d_size',
                          help="L1 data cache size. Default: %s" % size)

    def __init__(self, opts=None):
        super(L1DCache, self).__init__(opts)
        if not opts or not opts.l1d_size:
            return
        self.size = opts.l1d_size

    def connectCPU(self, cpu):
        """Connect this cache's port to a CPU dcache port"""
        self.cpu_side = cpu.dcache_port

class MMUCache(Cache):
    # Default parameters
    size = '8kB'
    assoc = 4
    tag_latency = 1
    data_latency = 1
    response_latency = 1
    mshrs = 20
    tgts_per_mshr = 12
    writeback_clean = True

    def __init__(self):
        super(MMUCache, self).__init__()

    def connectCPU(self, cpu):
        """Connect the CPU itb and dtb to the cache
           Note: This creates a new crossbar
        """
        self.mmubus = L2XBar()
        self.cpu_side = self.mmubus.master
        for tlb in [cpu.itb, cpu.dtb]:
            self.mmubus.slave = tlb.walker.port

    def connectBus(self, bus):
        """Connect this cache to a memory-side bus"""
        self.mem_side = bus.slave

class L2Cache(PrefetchCache):
    """Simple L2 Cache with default values"""

    # Default parameters
    size = '256kB'
    assoc = 16
    tag_latency = 10
    data_latency = 10
    response_latency = 1
    mshrs = 20
    tgts_per_mshr = 12
    writeback_clean = True

    SimpleOpts.add_option('--l2_size',
                          help="L2 cache size. Default: %s" % size)

    def __init__(self, opts=None):
        super(L2Cache, self).__init__(opts)
        if not opts or not opts.l2_size:
            return
        self.size = opts.l2_size

    def connectCPUSideBus(self, bus):
        self.cpu_side = bus.master

    def connectMemSideBus(self, bus):
        self.mem_side = bus.slave

class L3Cache(Cache):
    """Simple L3 Cache bank with default values
       This assumes that the L3 is made up of multiple banks. This cannot
       be used as a standalone L3 cache.
    """

    SimpleOpts.add_option('--l3_size', default = '4MB',
                          help="L3 cache size. Default: 4MB")

    # Default parameters
    assoc = 32
    tag_latency = 40
    data_latency = 40
    response_latency = 10
    mshrs = 256
    tgts_per_mshr = 12
    clusivity = 'mostly_excl'

    def __init__(self, opts):
        super(L3Cache, self).__init__()
        self.size = (opts.l3_size)

    def connectCPUSideBus(self, bus):
        self.cpu_side = bus.master

    def connectMemSideBus(self, bus):
        self.mem_side = bus.slave