ps2: Factor out PS/2 devices into their own subsystem

PS/2 devices are currently emulated both in the i8042 model and the
Arm KMI model. This is undesirable since it leads to code duplication.

This change introduces a common PS/2 device interface and factor out
the x86 keyboard and mouse model. A subsequent commit will implement
support for this interface in the Arm KMI model.

Change-Id: I440e83517fd9dce362fdc1676db477cc6eee5211
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/9762
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

1 files changed, 134 insertions, 0 deletions

diff --git a/src/dev/ps2/device.hh b/src/dev/ps2/device.hh
new file mode 100644
index 000000000..5252ac8d8
--- /dev/null
+++ b/src/dev/ps2/device.hh
@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2017-2018 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.
+ *
+ * Copyright (c) 2008 The Regents of The University of Michigan
+ * 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.
+ *
+ * Authors: Gabe Black
+ *          Andreas Sandberg
+ */
+
+#ifndef __DEV_PS2_DEVICE_HH__
+#define __DEV_PS2_DEVICE_HH__
+
+#include <deque>
+
+#include "sim/sim_object.hh"
+
+struct PS2DeviceParams;
+
+class PS2Device : public SimObject
+{
+  public:
+    PS2Device(const PS2DeviceParams *p);
+
+    void serialize(CheckpointOut &cp) const override;
+    void unserialize(CheckpointIn &cp) override;
+
+  public: /* Host interface */
+    /**
+     * Register a data available callback into the PS/2 interface
+     *
+     * @param c Callback instance from host interface
+     */
+    void hostRegDataAvailable(const std::function<void()> &c);
+
+    /**
+     * Check if there is pending data from the PS/2 device.
+     *
+     * @return true if there is data pending that can be read using
+     * the readData() method.
+     */
+    bool hostDataAvailable() const  { return !outBuffer.empty(); }
+
+    /**
+     * Read a character from the device.
+     *
+     * @return Character from the device's output buffer, undefined if
+     * no data is pending.
+     */
+    uint8_t hostRead();
+
+    /**
+     * Transmit a character from the host interface to the device.
+     *
+     * @param c Received data.
+     */
+    void hostWrite(uint8_t c);
+
+  protected: /* Device interface */
+    /**
+     * Data received from host.
+     */
+    virtual void recv(uint8_t data) = 0;
+
+    /**
+     * Send data from a PS/2 device to a host
+     *
+     * @param data Pointer to data array
+     * @param size Size of the data array
+     */
+    void send(const uint8_t *data, size_t size);
+    void send(const std::vector<uint8_t> &data) {
+        send(data.data(), data.size());
+    }
+
+    /**
+     * Send a byte of data from a PS/2 device to a host
+     *
+     * @param data Byte to send
+     */
+    void send(uint8_t data) { send(&data, 1); }
+
+    /** Send an ACK byte to the host */
+    void sendAck();
+
+    /**
+     * Output buffer size
+     *
+     * Device models may use this method to query the size of the
+     * output buffer to do rate limiting.
+     */
+    size_t sendPending() const { return outBuffer.size(); }
+
+  private:
+    /** Device -> host FIFO */
+    std::deque<uint8_t> outBuffer;
+
+    std::function<void()> dataAvailableCallback;
+};
+
+#endif // __DEV_PS2_HOUSE_HH__