From da5356cccea52dfc49ce2adf07049b2ac9dea7b9 Mon Sep 17 00:00:00 2001 From: Andreas Hansson Date: Fri, 1 Mar 2013 13:20:32 -0500 Subject: [PATCH] mem: Add a method to build multi-channel DRAM configurations This patch adds a class method that allows easy creation of channel-interleaved multi-channel DRAM configurations. It is enabled by a class method to allow customisation of the class independent of the channel configuration. For example, the user can create a MyDDR subclass of e.g. SimpleDDR3, and then create a four-channel configuration of the subclass by calling MyDDR.makeMultiChannel(4, mem_start, mem_size). --- src/mem/SimpleDRAM.py | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) diff --git a/src/mem/SimpleDRAM.py b/src/mem/SimpleDRAM.py index 0e43a6a39..60bc1cffb 100644 --- a/src/mem/SimpleDRAM.py +++ b/src/mem/SimpleDRAM.py @@ -1,4 +1,4 @@ -# Copyright (c) 2012 ARM Limited +# Copyright (c) 2012-2013 ARM Limited # All rights reserved. # # The license below extends only to copyright in the software and shall @@ -59,6 +59,38 @@ class SimpleDRAM(AbstractMemory): type = 'SimpleDRAM' cxx_header = "mem/simple_dram.hh" + @classmethod + def makeMultiChannel(cls, nbr_mem_ctrls, mem_start_addr, mem_size, + intlv_high_bit = 11): + """ + Make a multi-channel configuration of this class. + + Create multiple instances of the specific class and set their + parameters such that the address range is interleaved between + them. + + Returns a list of controllers. + """ + import math + from m5.util import fatal + intlv_bits = int(math.log(nbr_mem_ctrls, 2)) + if 2 ** intlv_bits != nbr_mem_ctrls: + fatal("Number of memory channels must be a power of 2") + mem_ctrls = [] + for i in xrange(nbr_mem_ctrls): + # The default interleaving granularity is tuned to match a + # row buffer size of 32 cache lines of 64 bytes (starting + # at bit 11 for 2048 bytes). There is unfortunately no + # good way of checking this at instantiation time. + mem_ctrls.append(cls(range = AddrRange(mem_start_addr, + size = mem_size, + intlvHighBit = \ + intlv_high_bit, + intlvBits = intlv_bits, + intlvMatch = i), + channels = nbr_mem_ctrls)) + return mem_ctrls + # single-ported on the system interface side, instantiate with a # bus in front of the controller for multiple ports port = SlavePort("Slave port")