dev: Added new LupIO-RNG device
This device is a random number generator that uses the Mersenne
Twister in order to provide the system with a set of random
numbers. It is implemented as a BasicPioDevice, and has both
read and write capabilities.
The following are the specifications regarding the LupIO-RNG:
https://gitlab.com/luplab/lupio/lupio-specs/-/blob/main/lupio-rng.md
Change-Id: Ia6aeb610ebe5589ed1f1548b823c5165236b03e6
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/53029
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
diff --git a/src/dev/lupio/LupioRNG.py b/src/dev/lupio/LupioRNG.py
new file mode 100644
index 0000000..c6d2c17
--- /dev/null
+++ b/src/dev/lupio/LupioRNG.py
@@ -0,0 +1,40 @@
+# Copyright (c) 2021 The Regents of the University of California
+# All rights reserved.
+#
+# 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.
+
+from m5.objects.Device import BasicPioDevice
+from m5.params import Param
+from m5.proxy import Parent
+
+class LupioRNG(BasicPioDevice):
+
+ type = 'LupioRNG'
+ cxx_class='gem5::LupioRNG'
+ cxx_header = 'dev/lupio/lupio_rng.hh'
+ pio_size = Param.Addr(0x1000, "PIO Size")
+ seed = Param.Int(0, "Initial seed for the random number generator")
+ platform = Param.Platform(Parent.any,
+ "Platform this device is part of.")
+ int_id = Param.Int("Interrupt ID to be used by the PIC")
diff --git a/src/dev/lupio/SConscript b/src/dev/lupio/SConscript
index 30fbbe0..775412c 100644
--- a/src/dev/lupio/SConscript
+++ b/src/dev/lupio/SConscript
@@ -27,7 +27,10 @@
Import('*')
SimObject('LupioRTC.py', tags='riscv isa')
+SimObject('LupioRNG.py', tags='riscv isa')
+DebugFlag('LupioRNG')
DebugFlag('LupioRTC')
Source('lupio_rtc.cc', tags='riscv isa')
+Source('lupio_rng.cc', tags='riscv isa')
diff --git a/src/dev/lupio/lupio_rng.cc b/src/dev/lupio/lupio_rng.cc
new file mode 100644
index 0000000..f3036de
--- /dev/null
+++ b/src/dev/lupio/lupio_rng.cc
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2021 The Regents of the University of California
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+#include "dev/lupio/lupio_rng.hh"
+
+#include <random>
+
+#include "debug/LupioRNG.hh"
+#include "mem/packet_access.hh"
+#include "params/LupioRNG.hh"
+
+/* CTRL fields */
+#define LUPIO_RNG_IRQE 0x1
+/* STAT fields */
+#define LUPIO_RNG_BUSY 0x1
+
+namespace gem5
+{
+
+LupioRNG::LupioRNG(const Params ¶ms) :
+ BasicPioDevice(params, params.pio_size),
+ user_seed(params.seed)
+{
+ mt.seed(user_seed);
+ DPRINTF(LupioRNG, "LupioRNG initalized with seed: %d\n", user_seed);
+}
+
+uint64_t
+LupioRNG::lupioRNGRead(uint8_t addr)
+{
+ uint32_t r = 0;
+ std::uniform_int_distribution<uint32_t> distrib(0);
+
+ switch (addr >> 2) {
+ // returns a random number
+ case LUPIO_RNG_RAND:
+ r = distrib(mt);
+ DPRINTF(LupioRNG, "Random number: %#x\n", r );
+ break;
+ // returns the current seed being used
+ case LUPIO_RNG_SEED:
+ r = user_seed;
+ DPRINTF(LupioRNG, "RNG_SEED Call: %d\n", r);
+ break;
+ // returns status of the device
+ case LUPIO_RNG_STAT:
+ r = 0; /* Always ready */
+ DPRINTF(LupioRNG, "RNG_STAT Call: %d\n", r);
+ break;
+ default:
+ r = -1;
+ panic("Unexpected read to the LupioRTC device at address %d!",
+ addr);
+ break;
+ }
+ return r;
+}
+
+void
+LupioRNG::lupioRNGWrite(uint8_t addr, uint64_t val64)
+{
+ switch (addr >> 2) {
+ // allows the user to configure the seed value
+ case LUPIO_RNG_SEED:
+ user_seed = val64;
+ mt.seed(user_seed);
+ DPRINTF(LupioRNG, "RNG_SEED_WRITE: %d\n", user_seed);
+ break;
+ // configures the device using interrupts
+ case LUPIO_RNG_CTRL:
+ interrupt_enable = !!(val64 & LUPIO_RNG_IRQE);
+ DPRINTF(LupioRNG, "RNG_CTRL Call: %d\n", interrupt_enable);
+ break;
+ default:
+ panic("Unexpected write to the LupioRTC device at address %d!",
+ addr);
+ break;
+ }
+}
+
+Tick
+LupioRNG::read(PacketPtr pkt)
+{
+ Addr rng_addr = pkt->getAddr() - pioAddr;
+
+ DPRINTF(LupioRNG,
+ "Read request - addr: %#x, size: %#x\n", rng_addr, pkt->getSize());
+
+ uint64_t rand_read = lupioRNGRead(rng_addr);
+ DPRINTF(LupioRNG, "Packet Read: %#x\n", rand_read);
+ pkt->setUintX(rand_read, byteOrder);
+ pkt->makeResponse();
+
+ return pioDelay;
+}
+
+Tick
+LupioRNG::write(PacketPtr pkt)
+{
+ Addr daddr = pkt->getAddr() - pioAddr;
+
+ DPRINTF(LupioRNG, "Write register %#x value %#x\n", daddr,
+ pkt->getUintX(byteOrder));
+
+ lupioRNGWrite(daddr, pkt->getUintX(byteOrder));
+ DPRINTF(LupioRNG, "Packet Write Value: %d\n", pkt->getUintX(byteOrder));
+
+ pkt->makeResponse();
+
+ return pioDelay;
+}
+} // namespace gem5
diff --git a/src/dev/lupio/lupio_rng.hh b/src/dev/lupio/lupio_rng.hh
new file mode 100644
index 0000000..70d64e4
--- /dev/null
+++ b/src/dev/lupio/lupio_rng.hh
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2021 The Regents of the University of California
+ * All rights reserved.
+ *
+ * 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.
+ */
+
+#ifndef __DEV_LUPIO_LUPIO_RNG_HH__
+#define __DEV_LUPIO_LUPIO_RNG_HH__
+
+#include <random>
+
+#include "debug/LupioRNG.hh"
+#include "dev/io_device.hh"
+#include "params/LupioRNG.hh"
+#include "sim/system.hh"
+
+namespace gem5
+{
+
+/**
+ * LupioRNG:
+ * A Random Number Generator virtual device that returns either a random
+ * value, or a seed that can be configured by the user.
+ */
+class LupioRNG : public BasicPioDevice
+{
+ protected:
+ const ByteOrder byteOrder = ByteOrder::little;
+
+ // Register map
+ private:
+ enum
+ {
+ LUPIO_RNG_RAND,
+ LUPIO_RNG_SEED,
+ LUPIO_RNG_CTRL,
+ LUPIO_RNG_STAT,
+ };
+
+ std::mt19937 mt;
+ uint64_t user_seed;
+ bool interrupt_enable = false;
+
+ /**
+ * Function to return a random number, the current seed, or the device
+ * status
+ */
+ uint64_t lupioRNGRead(const uint8_t addr);
+ /**
+ * Function to allow the user to change the current seed, and configure
+ * the device using interrupts
+ */
+ void lupioRNGWrite(const uint8_t addr, const uint64_t val64);
+
+ public:
+ PARAMS(LupioRNG);
+ LupioRNG(const Params ¶ms);
+
+ /**
+ * Implement BasicPioDevice virtual functions
+ */
+ Tick read(PacketPtr pkt) override;
+ Tick write(PacketPtr pkt) override;
+};
+
+} // namespace gem5
+
+#endif // __DEV_LUPIO_LUPIO_RNG_HH__
