diff --git a/services/inputflinger/PreferStylusOverTouchBlocker.cpp b/services/inputflinger/PreferStylusOverTouchBlocker.cpp
new file mode 100644
index 0000000..ad639b4
--- /dev/null
+++ b/services/inputflinger/PreferStylusOverTouchBlocker.cpp
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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 "PreferStylusOverTouchBlocker.h"
+
+#include <android-base/stringprintf.h>
+
+using android::base::StringPrintf;
+
+static const char* toString(bool value) {
+    return value ? "true" : "false";
+}
+
+namespace android {
+
+ftl::StaticVector<NotifyMotionArgs, 2> PreferStylusOverTouchBlocker::processMotion(
+        const NotifyMotionArgs& args) {
+    const bool isStylusEvent = isFromSource(args.source, AINPUT_SOURCE_STYLUS);
+    if (isStylusEvent) {
+        for (size_t i = 0; i < args.pointerCount; i++) {
+            // Make sure we are canceling stylus pointers
+            const int32_t toolType = args.pointerProperties[i].toolType;
+            LOG_ALWAYS_FATAL_IF(toolType != AMOTION_EVENT_TOOL_TYPE_STYLUS &&
+                                        toolType != AMOTION_EVENT_TOOL_TYPE_ERASER,
+                                "The pointer %zu has toolType=%i, but the source is STYLUS. If "
+                                "simultaneous touch and stylus is supported, "
+                                "'PreferStylusOverTouchBlocker' should be disabled.",
+                                i, toolType);
+        }
+    }
+    const bool isDown = args.action == AMOTION_EVENT_ACTION_DOWN;
+    const bool isUpOrCancel =
+            args.action == AMOTION_EVENT_ACTION_UP || args.action == AMOTION_EVENT_ACTION_CANCEL;
+    if (isStylusEvent) {
+        if (isDown) {
+            // Reject all touch while stylus is down
+            mIsStylusDown = true;
+            if (mIsTouchDown && !mCurrentTouchIsCanceled) {
+                // Cancel touch!
+                mCurrentTouchIsCanceled = true;
+                mLastTouchEvent.action = AMOTION_EVENT_ACTION_CANCEL;
+                mLastTouchEvent.flags |= AMOTION_EVENT_FLAG_CANCELED;
+                mLastTouchEvent.eventTime = systemTime(SYSTEM_TIME_MONOTONIC);
+                return {mLastTouchEvent, args};
+            }
+        }
+        if (isUpOrCancel) {
+            mIsStylusDown = false;
+        }
+        // Never drop stylus events
+        return {args};
+    }
+
+    const bool isTouchEvent =
+            isFromSource(args.source, AINPUT_SOURCE_TOUCHSCREEN) && !isStylusEvent;
+    if (isTouchEvent) {
+        if (mIsStylusDown) {
+            mCurrentTouchIsCanceled = true;
+        }
+        // If we already canceled the current gesture, then continue to drop events from it, even if
+        // the stylus has been lifted.
+        if (mCurrentTouchIsCanceled) {
+            if (isUpOrCancel) {
+                mCurrentTouchIsCanceled = false;
+            }
+            return {};
+        }
+
+        // Update state
+        mLastTouchEvent = args;
+        if (isDown) {
+            mIsTouchDown = true;
+        }
+        if (isUpOrCancel) {
+            mIsTouchDown = false;
+            mCurrentTouchIsCanceled = false;
+        }
+        return {args};
+    }
+
+    // Not a touch or stylus event
+    return {args};
+}
+
+std::string PreferStylusOverTouchBlocker::dump() {
+    std::string out;
+    out += StringPrintf("mIsTouchDown: %s\n", toString(mIsTouchDown));
+    out += StringPrintf("mIsStylusDown: %s\n", toString(mIsStylusDown));
+    out += StringPrintf("mLastTouchEvent: %s\n", mLastTouchEvent.dump().c_str());
+    out += StringPrintf("mCurrentTouchIsCanceled: %s\n", toString(mCurrentTouchIsCanceled));
+    return out;
+}
+
+} // namespace android