Secure DPU: add folder for common headers

The header SecureDPU.h is moved out from the device specific folder as
it can be shared for different devices.

Bug: 176508588
Test: Pass TUI VTS test on the emulator.
Change-Id: I7695b49c4f7a247b570ced61145471efef3d0a3d

trusty/secure_dpu/Android.bp

@@ -0,0 +1,20 @@
+// Copyright (C) 2021 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.
+
+cc_library_headers {
+    name: "secure_dpu_headers",
+    vendor: true,
+
+    export_include_dirs: ["include"],
+}

trusty/secure_dpu/include/trusty/secure_dpu/SecureDpu.h

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2020, 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.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+/**
+ * DOC: Secure DPU
+ *
+ * The Secure DPU works as the persistent channel between the non-secure and the
+ * secure world. The channel is established during the boot up stage of the
+ * non-secure world system. In general, the established channel allows the
+ * secure world applications initiate requests or notifications to the non-secure
+ * world.
+ *
+ * For particular devices, the secure world can only perform operations on the
+ * display when in the TUI session if device-specific setup is done by the
+ * non-secure world. Besides, the non-secure world could allocate framebuffer
+ * for the secure world application if the memory is limited in the secure world
+ * on specific devices.
+ *
+ * Currently, supported requests are to start / stop the secure display mode and
+ * to allocate framebuffer.
+ *
+ * This header file needs to be synced on both the Trusty and the Android
+ * codebase.
+ */
+
+#define SECURE_DPU_PORT_NAME "com.android.trusty.secure_dpu"
+#define SECURE_DPU_MAX_MSG_SIZE 64
+
+/**
+ * enum secure_dpu_cmd - command identifiers for secure_fb interface
+ * @SECURE_DPU_CMD_RESP_BIT:
+ *      Message is a response.
+ * @SECURE_DPU_CMD_REQ_SHIFT:
+ *      Number of bits used by @SECURE_DPU_CMD_RESP_BIT.
+ * @SECURE_DPU_CMD_START_SECURE_DISPLAY:
+ *      Notify the system to start secure display mode
+ * @SECURE_DPU_CMD_STOP_SECURE_DISPLAY:
+ *      Notify the system to stop secure display mode
+ * @SECURE_DPU_CMD_ALLOCATE_BUFFER:
+ *      Request non-secure world to allocate the buffer
+ */
+enum secure_dpu_cmd {
+    SECURE_DPU_CMD_RESP_BIT = 1,
+    SECURE_DPU_CMD_REQ_SHIFT = 1,
+    SECURE_DPU_CMD_START_SECURE_DISPLAY = (1 << SECURE_DPU_CMD_REQ_SHIFT),
+    SECURE_DPU_CMD_STOP_SECURE_DISPLAY = (2 << SECURE_DPU_CMD_REQ_SHIFT),
+    SECURE_DPU_CMD_ALLOCATE_BUFFER = (3 << SECURE_DPU_CMD_REQ_SHIFT),
+};
+
+/**
+ * struct secure_dpu_allocate_buffer_req - payload for
+ *                                         %SECURE_DPU_CMD_ALLOCATE_BUFFER
+ *                                         request
+ * @buffer_len: Requested length
+ */
+struct secure_dpu_allocate_buffer_req {
+    uint64_t buffer_len;
+};
+
+/**
+ * struct secure_dpu_allocate_buffer_resp - payload for
+ *                                          %SECURE_DPU_CMD_ALLOCATE_BUFFER
+ *                                          response
+ * @buffer_len: Allocated length
+ */
+struct secure_dpu_allocate_buffer_resp {
+    uint64_t buffer_len;
+};
+
+/**
+ * struct secure_fb_req - common structure for secure_fb requests.
+ * @cmd: Command identifier - one of &enum secure_dpu_cmd.
+ */
+struct secure_dpu_req {
+    uint32_t cmd;
+};
+
+/**
+ * struct secure_dpu_resp - common structure for secure_dpu responses.
+ * @cmd:    Command identifier - %SECURE_DPU_CMD_RESP_BIT or'ed with the
+ *                               command identifier of the corresponding
+ *                               request.
+ * @status: Status of requested operation. One of &enum secure_dpu_error.
+ */
+struct secure_dpu_resp {
+    uint32_t cmd;
+    int32_t status;
+};
+
+enum secure_dpu_error {
+    SECURE_DPU_ERROR_OK = 0,
+    SECURE_DPU_ERROR_FAIL = -1,
+    SECURE_DPU_ERROR_UNINITIALIZED = -2,
+    SECURE_DPU_ERROR_PARAMETERS = -3,
+    SECURE_DPU_ERROR_NO_MEMORY = -4,
+};