mem: Implement base QoS Policies.

This patch implements a base fixed priority policy and an ideal
turnaround policy for the QoS memory controller.

Change-Id: I38ce16f845fc0ec86d6fc4cc5dc5406f213a465e
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/11972
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

1 files changed, 72 insertions, 0 deletions

diff --git a/src/mem/qos/turnaround_policy_ideal.hh b/src/mem/qos/turnaround_policy_ideal.hh
new file mode 100644
index 000000000..e28c55cf3
--- /dev/null
+++ b/src/mem/qos/turnaround_policy_ideal.hh
@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2018 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.
+ *
+ * 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: Matteo Andreozzi
+ */
+
+#ifndef __MEM_QOS_TURNAROUND_POLICY_IDEAL_HH_
+#define __MEM_QOS_TURNAROUND_POLICY_IDEAL_HH_
+
+#include "mem/qos/turnaround_policy.hh"
+
+namespace QoS {
+
+/**
+ * Ideal QoS Bus Turnaround policy
+ *
+ * Selects bus state based purely on highest QoS priority
+ * queue with at least one packet. Tie breaks across read
+ * and write queues are resolved by selecting current bus
+ * state.
+ */
+class TurnaroundPolicyIdeal: public TurnaroundPolicy
+{
+  public:
+    TurnaroundPolicyIdeal(const Params*);
+
+    virtual ~TurnaroundPolicyIdeal();
+
+    /**
+     * Bus Selection function.
+     *
+     * @return selected bus state
+     */
+    virtual MemCtrl::BusState selectBusState() override;
+};
+
+} // namespace QoS
+
+#endif /* __MEM_QOS_TURNAROUND_POLICY_IDEAL_HH_ */