dsp: file: Add encode req & decode resp for DfOpen command

Added encode/decode APIs for DfOpen command(0x01)
which is defined in DSP0242 Version 1.0.0 Section: 9.2.

Change-Id: I5a975a7ae2bbd4115898486984ad96016590b04b
Signed-off-by: Chau Ly <chaul@amperecomputing.com>
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a3afd66..f3327ff 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -41,6 +41,8 @@
 - platform: Add decode_pldm_file_descriptor_pdr() and
   decode_pldm_file_descriptor_pdr_names()
 
+- file: Add encode req & decode resp for DfOpen command.
+
 ### Changed
 
 - dsp: firmware_update: Expand "params" in symbol names
diff --git a/include/libpldm/base.h b/include/libpldm/base.h
index f74404e..9088d80 100644
--- a/include/libpldm/base.h
+++ b/include/libpldm/base.h
@@ -28,6 +28,7 @@
 	PLDM_FRU = 0x04,
 	PLDM_FWUP = 0x05,
 	PLDM_RDE = 0x06,
+	PLDM_FILE = 0x07,
 	PLDM_OEM = 0x3f,
 };
 
diff --git a/include/libpldm/file.h b/include/libpldm/file.h
new file mode 100644
index 0000000..0c0eb0e
--- /dev/null
+++ b/include/libpldm/file.h
@@ -0,0 +1,101 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
+#ifndef LIBPLDM_FILE_H
+#define LIBPLDM_FILE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <libpldm/pldm_types.h>
+
+#include <asm/byteorder.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#define PLDM_DF_OPEN_REQ_BYTES	4
+#define PLDM_DF_OPEN_RESP_BYTES 3
+
+/** @brief PLDM File Transfer Completion Code */
+enum pldm_file_cc {
+	PLDM_FILE_CC_INVALID_FILE_DESCRIPTOR = 0x80,
+	PLDM_FILE_CC_INVALID_DF_ATTRIBUTE = 0x81,
+	PLDM_FILE_CC_ZEROLENGTH_NOT_ALLOWED = 0x82,
+	PLDM_FILE_CC_EXCLUSIVE_OWNERSHIP_NOT_ESTABLISHED = 0x83,
+	PLDM_FILE_CC_EXCLUSIVE_OWNERSHIP_NOT_ALLOWED = 0x84,
+	PLDM_FILE_CC_EXCLUSIVE_OWNERSHIP_NOT_AVAILABLE = 0x85,
+	PLDM_FILE_CC_INVALID_FILE_IDENTIFIER = 0x86,
+	PLDM_FILE_CC_DFOPEN_DIR_NOT_ALLOWED = 0x87,
+	PLDM_FILE_CC_MAX_NUM_FDS_EXCEEDED = 0x88,
+	PLDM_FILE_CC_FILE_OPEN = 0x89,
+	PLDM_FILE_CC_UNABLE_TO_OPEN_FILE = 0x8A,
+};
+
+/** @brief PLDM File Transfer Command */
+enum pldm_file_cmd {
+	PLDM_FILE_CMD_DF_OPEN = 0x01,
+	PLDM_FILE_CMD_DF_CLOSE = 0x02,
+	PLDM_FILE_CMD_DF_HEARTBEAT = 0x03,
+	PLDM_FILE_CMD_DF_PROPERTIES = 0x10,
+	PLDM_FILE_CMD_DF_GET_FILE_ATTRIBUTE = 0x11,
+	PLDM_FILE_CMD_DF_SET_FILE_ATTRIBUTE = 0x12,
+	PLDM_FILE_CMD_DF_READ = 0x20,
+	PLDM_FILE_CMD_DF_FIFO_SEND = 0x21,
+};
+
+/** @struct pldm_file_df_open_req
+ *
+ *  Structure representing PLDM File DfOpen request.
+ */
+struct pldm_file_df_open_req {
+	uint16_t file_identifier;
+	bitfield16_t file_attribute;
+};
+
+/** @struct pldm_file_df_open_resp
+ *
+ *  Structure representing PLDM File DfOpen response.
+ */
+struct pldm_file_df_open_resp {
+	uint8_t completion_code;
+	uint16_t file_descriptor;
+};
+
+/** @brief Create a PLDM request message for DFOpen
+ *
+ *  @param[in] instance_id - Message's instance id
+ *  @param[in] req - The pointer to the request message to be encoded
+ *  @param[in,out] msg - Message will be written to this
+ *  @param[in] payload_length - Length of the request message payload
+ *  @return 0 on success
+ *          -EINVAL if the input parameters' memory are not allocated,
+ *          or message type or instance in request header is invalid
+ *          -ENOMSG if the PLDM type in the request header is invalid
+ *          -EOVERFLOW if the input message length is invalid
+ *  @note  Caller is responsible for memory alloc and dealloc of param
+ *         'msg.payload'
+ */
+int encode_pldm_file_df_open_req(uint8_t instance_id,
+				 const struct pldm_file_df_open_req *req,
+				 struct pldm_msg *msg, size_t payload_length);
+
+/** @brief Decode DFOpen response data
+ *
+ *  @param[in] msg - Response message
+ *  @param[in] payload_length - Length of response message payload
+ *  @param[out] resp - pointer to the decoded response message
+ *  @return 0 on success
+ *          -EINVAL if the input parameters' memory are not allocated
+ *          -EOVERFLOW if the input message buffer is too short for the output
+ *          response struct
+ *          -EBADMSG if the input message buffer is too large for the output
+ *          response struct.
+ */
+int decode_pldm_file_df_open_resp(const struct pldm_msg *msg,
+				  size_t payload_length,
+				  struct pldm_file_df_open_resp *resp);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/include/libpldm/meson.build b/include/libpldm/meson.build
index 3a8c708..23785ff 100644
--- a/include/libpldm/meson.build
+++ b/include/libpldm/meson.build
@@ -6,6 +6,7 @@
     'compiler.h',
     'control.h',
     'entity.h',
+    'file.h',
     'firmware_fd.h',
     'firmware_update.h',
     'fru.h',
diff --git a/src/dsp/file.c b/src/dsp/file.c
new file mode 100644
index 0000000..d9c2a21
--- /dev/null
+++ b/src/dsp/file.c
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */
+#include "dsp/base.h"
+#include "msgbuf.h"
+
+#include <libpldm/base.h>
+#include <libpldm/file.h>
+#include <libpldm/utils.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+
+LIBPLDM_ABI_TESTING
+int encode_pldm_file_df_open_req(uint8_t instance_id,
+				 const struct pldm_file_df_open_req *req,
+				 struct pldm_msg *msg, size_t payload_length)
+{
+	PLDM_MSGBUF_DEFINE_P(buf);
+	int rc;
+
+	if (req == NULL || msg == NULL) {
+		return -EINVAL;
+	}
+
+	struct pldm_header_info header = { 0 };
+	header.instance = instance_id;
+	header.msg_type = PLDM_REQUEST;
+	header.pldm_type = PLDM_FILE;
+	header.command = PLDM_FILE_CMD_DF_OPEN;
+
+	rc = pack_pldm_header_errno(&header, &(msg->hdr));
+	if (rc) {
+		return rc;
+	}
+
+	rc = pldm_msgbuf_init_errno(buf, PLDM_DF_OPEN_REQ_BYTES, msg->payload,
+				    payload_length);
+	if (rc) {
+		return rc;
+	}
+
+	pldm_msgbuf_insert(buf, req->file_identifier);
+	pldm_msgbuf_insert(buf, req->file_attribute.value);
+
+	return pldm_msgbuf_complete(buf);
+}
+
+LIBPLDM_ABI_TESTING
+int decode_pldm_file_df_open_resp(const struct pldm_msg *msg,
+				  size_t payload_length,
+				  struct pldm_file_df_open_resp *resp)
+{
+	PLDM_MSGBUF_DEFINE_P(buf);
+	int rc;
+
+	if (!msg || !resp) {
+		return -EINVAL;
+	}
+
+	rc = pldm_msg_has_error(msg, payload_length);
+	if (rc) {
+		resp->completion_code = rc;
+		return 0;
+	}
+
+	rc = pldm_msgbuf_init_errno(buf, PLDM_DF_OPEN_RESP_BYTES, msg->payload,
+				    payload_length);
+	if (rc) {
+		return rc;
+	}
+
+	pldm_msgbuf_extract(buf, resp->completion_code);
+	pldm_msgbuf_extract(buf, resp->file_descriptor);
+
+	return pldm_msgbuf_complete_consumed(buf);
+}
diff --git a/src/dsp/meson.build b/src/dsp/meson.build
index b81e533..4a5bc41 100644
--- a/src/dsp/meson.build
+++ b/src/dsp/meson.build
@@ -2,6 +2,7 @@
     'base.c',
     'bios.c',
     'bios_table.c',
+    'file.c',
     'firmware_update.c',
     'fru.c',
     'pdr.c',
diff --git a/tests/dsp/file.cpp b/tests/dsp/file.cpp
new file mode 100644
index 0000000..f738377
--- /dev/null
+++ b/tests/dsp/file.cpp
@@ -0,0 +1,166 @@
+#include <libpldm/file.h>
+#include <libpldm/pldm_types.h>
+
+#include <array>
+#include <cstdint>
+#include <cstring>
+#include <vector>
+
+#include "msgbuf.h"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#ifdef LIBPLDM_API_TESTING
+TEST(EncodeDfOpenReq, GoodTest)
+{
+    uint8_t instance_id = 0;
+    uint16_t file_identifier = 0x0100;
+    bitfield16_t file_attribute;
+    file_attribute.value = 0x0400;
+    std::array<uint8_t, PLDM_DF_OPEN_REQ_BYTES> requestMsg = {0x00, 0x01, 0x00,
+                                                              0x04};
+
+    const struct pldm_file_df_open_req req_data = {file_identifier,
+                                                   file_attribute};
+
+    PLDM_MSG_DEFINE_P(requestPtr, PLDM_DF_OPEN_REQ_BYTES);
+    auto rc = encode_pldm_file_df_open_req(instance_id, &req_data, requestPtr,
+                                           PLDM_DF_OPEN_REQ_BYTES);
+
+    ASSERT_EQ(rc, 0);
+    EXPECT_EQ(
+        0, memcmp(requestPtr->payload, requestMsg.data(), sizeof(requestMsg)));
+}
+#endif
+
+#ifdef LIBPLDM_API_TESTING
+TEST(EncodeDfOpenReq, BadTestUnAllocatedPtrParams)
+{
+    uint8_t instance_id = 0;
+    uint16_t file_identifier = 0x0100;
+    bitfield16_t file_attribute;
+    file_attribute.value = 0x0400;
+    int rc;
+
+    const struct pldm_file_df_open_req req_data = {file_identifier,
+                                                   file_attribute};
+
+    PLDM_MSG_DEFINE_P(requestPtr, PLDM_DF_OPEN_REQ_BYTES);
+    rc = encode_pldm_file_df_open_req(instance_id, &req_data, nullptr,
+                                      PLDM_DF_OPEN_REQ_BYTES);
+    EXPECT_EQ(rc, -EINVAL);
+
+    rc = encode_pldm_file_df_open_req(instance_id, nullptr, requestPtr,
+                                      PLDM_DF_OPEN_REQ_BYTES);
+    EXPECT_EQ(rc, -EINVAL);
+}
+#endif
+
+#ifdef LIBPLDM_API_TESTING
+TEST(EncodeDfOpenReq, BadTestInvalidExpectedOutputMsgLength)
+{
+    uint8_t instance_id = 0;
+    uint16_t file_identifier = 0x0100;
+    bitfield16_t file_attribute;
+    file_attribute.value = 0x0400;
+    int rc;
+
+    const struct pldm_file_df_open_req req_data = {file_identifier,
+                                                   file_attribute};
+
+    PLDM_MSG_DEFINE_P(requestPtr, PLDM_DF_OPEN_REQ_BYTES);
+    rc = encode_pldm_file_df_open_req(instance_id, &req_data, requestPtr, 1);
+    EXPECT_EQ(rc, -EOVERFLOW);
+}
+#endif
+
+#ifdef LIBPLDM_API_TESTING
+TEST(DecodeDfOpenResp, GoodTest)
+{
+    uint8_t completion_code = PLDM_SUCCESS;
+    uint16_t file_descriptor = 20;
+
+    struct pldm_file_df_open_resp resp_data = {};
+
+    PLDM_MSGBUF_DEFINE_P(buf);
+    int rc;
+
+    static constexpr const size_t payload_length = PLDM_DF_OPEN_RESP_BYTES;
+
+    PLDM_MSG_DEFINE_P(responseMsg, payload_length);
+
+    rc = pldm_msgbuf_init_errno(buf, 0, responseMsg->payload, payload_length);
+    ASSERT_EQ(rc, 0);
+
+    pldm_msgbuf_insert_uint8(buf, completion_code);
+    pldm_msgbuf_insert_uint16(buf, file_descriptor);
+
+    ASSERT_EQ(pldm_msgbuf_complete_consumed(buf), 0);
+
+    rc = decode_pldm_file_df_open_resp(responseMsg, payload_length, &resp_data);
+
+    ASSERT_EQ(rc, 0);
+    EXPECT_EQ(resp_data.completion_code, completion_code);
+    EXPECT_EQ(resp_data.file_descriptor, file_descriptor);
+}
+#endif
+
+#ifdef LIBPLDM_API_TESTING
+TEST(DecodeDfOpenResp, BadTestUnAllocatedPtrParams)
+{
+    uint8_t completion_code = PLDM_SUCCESS;
+    uint16_t file_descriptor = 20;
+
+    struct pldm_file_df_open_resp resp_data = {};
+
+    PLDM_MSGBUF_DEFINE_P(buf);
+    int rc;
+
+    static constexpr const size_t payload_length = PLDM_DF_OPEN_RESP_BYTES;
+
+    PLDM_MSG_DEFINE_P(responseMsg, payload_length);
+
+    rc = pldm_msgbuf_init_errno(buf, 0, responseMsg->payload, payload_length);
+    ASSERT_EQ(rc, 0);
+
+    pldm_msgbuf_insert_uint8(buf, completion_code);
+    pldm_msgbuf_insert_uint16(buf, file_descriptor);
+
+    ASSERT_EQ(pldm_msgbuf_complete_consumed(buf), 0);
+
+    rc = decode_pldm_file_df_open_resp(nullptr, payload_length, &resp_data);
+    EXPECT_EQ(rc, -EINVAL);
+
+    rc = decode_pldm_file_df_open_resp(responseMsg, payload_length, nullptr);
+    EXPECT_EQ(rc, -EINVAL);
+}
+#endif
+
+#ifdef LIBPLDM_API_TESTING
+TEST(DecodeDfOpenResp, BadTestInvalidExpectedInputMsgLength)
+{
+    uint8_t completion_code = PLDM_SUCCESS;
+    uint16_t file_descriptor = 20;
+
+    struct pldm_file_df_open_resp resp_data = {};
+
+    PLDM_MSGBUF_DEFINE_P(buf);
+    int rc;
+
+    static constexpr const size_t payload_length = PLDM_DF_OPEN_RESP_BYTES;
+
+    PLDM_MSG_DEFINE_P(responseMsg, payload_length);
+
+    rc = pldm_msgbuf_init_errno(buf, 0, responseMsg->payload, payload_length);
+    ASSERT_EQ(rc, 0);
+
+    pldm_msgbuf_insert_uint8(buf, completion_code);
+    pldm_msgbuf_insert_uint16(buf, file_descriptor);
+
+    ASSERT_EQ(pldm_msgbuf_complete_consumed(buf), 0);
+
+    rc = decode_pldm_file_df_open_resp(responseMsg, 0, &resp_data);
+    EXPECT_EQ(rc, -EOVERFLOW);
+}
+#endif
diff --git a/tests/dsp/meson.build b/tests/dsp/meson.build
index dd2b5b0..64acb94 100644
--- a/tests/dsp/meson.build
+++ b/tests/dsp/meson.build
@@ -2,6 +2,7 @@
     'dsp/base',
     'dsp/bios_table',
     'dsp/bios',
+    'dsp/file',
     'dsp/firmware_update',
     'dsp/fru',
     'dsp/pdr',