Add a Mailbox interface

Change-Id: If68e70709c496849cb781af5f7288fa3f7ddcdb5

4 files changed, 165 insertions, 0 deletions

diff --git a/drivers/CMakeLists.txt b/drivers/CMakeLists.txt
new file mode 100644
index 0000000..cea6325
--- /dev/null
+++ b/drivers/CMakeLists.txt
@@ -0,0 +1,23 @@
+#
+# Copyright (c) 2020 Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the License); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an AS IS BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+add_library(ethosu_drivers INTERFACE)
+
+# Mailbox driver
+add_subdirectory(mailbox)
+target_link_libraries(ethosu_drivers INTERFACE mailbox)
diff --git a/drivers/mailbox/CMakeLists.txt b/drivers/mailbox/CMakeLists.txt
new file mode 100644
index 0000000..6d55407
--- /dev/null
+++ b/drivers/mailbox/CMakeLists.txt
@@ -0,0 +1,22 @@
+#
+# Copyright (c) 2020 Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the License); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an AS IS BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+add_library(mailbox STATIC)
+target_include_directories(mailbox PUBLIC include)
+target_sources(mailbox PRIVATE src/mailbox.cc)
+
diff --git a/drivers/mailbox/include/mailbox.hpp b/drivers/mailbox/include/mailbox.hpp
new file mode 100644
index 0000000..9074754
--- /dev/null
+++ b/drivers/mailbox/include/mailbox.hpp
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2020 Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef MAILBOX_HPP
+#define MAILBOX_HPP
+
+#include <cstddef>
+#include <list>
+
+namespace Mailbox {
+
+class Mailbox {
+public:
+    Mailbox();
+    virtual ~Mailbox();
+    virtual bool sendMessage() = 0;
+    virtual void handleMessage() = 0;
+    virtual bool verifyHardware();
+    typedef void (*CallbackFptr)(void *userArg);
+    void registerCallback(CallbackFptr callback, void *userArg);
+    void deregisterCallback(CallbackFptr callback, void *userArg);
+
+protected:
+    void notify();
+    uint32_t read32(volatile uint32_t *baseAddr, const uint32_t offset);
+    void write32(volatile uint32_t *baseAddr, const uint32_t offset, const uint32_t value);
+
+private:
+    struct Callback {
+        bool operator==(const Callback &b) const;
+        CallbackFptr callback;
+        void *userArg;
+    };
+
+    std::list<Callback> callbacks;
+};
+
+} // namespace Mailbox
+
+#endif
diff --git a/drivers/mailbox/src/mailbox.cc b/drivers/mailbox/src/mailbox.cc
new file mode 100644
index 0000000..0d3dfed
--- /dev/null
+++ b/drivers/mailbox/src/mailbox.cc
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2020 Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <mailbox.hpp>
+
+#include <cstddef>
+#include <cassert>
+
+namespace Mailbox {
+
+Mailbox::Mailbox() {}
+Mailbox::~Mailbox() {}
+
+bool Mailbox::verifyHardware() {
+    return true;
+}
+
+void Mailbox::registerCallback(CallbackFptr callback, void *userArg) {
+    callbacks.push_back({callback, userArg});
+}
+
+void Mailbox::deregisterCallback(CallbackFptr callback, void *userArg) {
+    callbacks.remove({callback, userArg});
+}
+
+void Mailbox::notify() {
+    for (auto &it : callbacks) {
+        it.callback(it.userArg);
+    }
+}
+
+uint32_t Mailbox::read32(volatile uint32_t *baseAddr, const uint32_t offset) {
+    assert(offset % 4 == 0);
+    volatile uint32_t *addr = baseAddr + (offset / 4);
+
+    return *addr;
+}
+
+void Mailbox::write32(volatile uint32_t *baseAddr, const uint32_t offset, const uint32_t value) {
+    assert(offset % 4 == 0);
+    volatile uint32_t *addr = baseAddr + (offset / 4);
+
+    *addr = value;
+}
+
+bool Mailbox::Callback::operator==(const Callback &b) const {
+    return (callback == b.callback && userArg == b.userArg);
+}
+
+} // namespace Mailbox