hmc_controller.hh revision 11184:07b0dacf27d6 
1/*
2 * Copyright (c) 2011-2013 ARM Limited
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4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
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8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder.  You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
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13 *
14 * Copyright (c) 2015 The University of Bologna
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16 *
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18 * modification, are permitted provided that the following conditions are
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28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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39 *
40 * Authors: Erfan Azarkhish
41 */
42
43
44/**
45 * @file
46 * HMCController declaration
47 */
48
49#ifndef __HMC_CONTROLLER__
50#define __HMC_CONTROLLER__
51
52#include "mem/noncoherent_xbar.hh"
53#include "mem/port.hh"
54#include "params/HMCController.hh"
55
56/**
57 * HMC Controller, in general, is responsible for translating the host
58 * protocol (AXI for example) to serial links protocol. Plus, it should have
59 * large internal buffers to hide the access latency of the cube. It is also
60 * inferred from the standard [1] and the literature [2] that serial links
61 * share the same address range and packets can travel over any of them, so a
62 * load distribution mechanism is required.
63 * This model simply queues the incoming transactions (using a Bridge) and
64 * schedules them to the serial links using a simple round robin mechanism to
65 * balance the load among them. More advanced global scheduling policies and
66 * reordering and steering of transactions can be added to this model if
67 * required [3].
68 * [1] http://www.hybridmemorycube.org/specification-download/
69 * [2] Low-Power Hybrid Memory Cubes With Link Power Manageme and Two-Level
70 * Prefetching (J. Ahn et. al)
71 * [3] The Open-Silicon HMC Controller IP
72 * http://www.open-silicon.com/open-silicon-ips/hmc/
73 */
74
75class HMCController : public NoncoherentXBar
76{
77public:
78
79    HMCController(const HMCControllerParams *p);
80
81private:
82
83    // Receive range change only on one of the ports (because they all have
84    //  the same range)
85    virtual void recvRangeChange(PortID master_port_id);
86
87    // Receive a request and distribute it among slave ports
88    //  Simply forwards the packet to the next serial link based on a
89    //  Round-robin counter
90    virtual bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
91
92    int n_master_ports;
93
94    // The round-robin counter
95    int rr_counter;
96    /**
97     * Function for rotating the round robin counter
98     * @return the next value of the counter
99     */
100    int rotate_counter();
101};
102
103#endif //__HMC_CONTROLLER__
104