[v6,3/3] net/iavf: add Tx LLDP command

diff --git a/doc/guides/nics/intel_vf.rst b/doc/guides/nics/intel_vf.rst
index ad08198f0f..ce96c2e1f8 100644
--- a/doc/guides/nics/intel_vf.rst
+++ b/doc/guides/nics/intel_vf.rst
@@ -627,6 +627,23 @@  Inline IPsec Support
     documentation.
 
 
+Diagnostic Utilities
+--------------------
+
+Register mbuf dynfield to test Tx LLDP
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Register an mbuf dynfield IAVF_TX_LLDP_DYNFIELD on dev_start to indicate
+the need to send LLDP packet, this dynfield needs to be set to 1 when
+preparing packet.
+
+For dpdk-testpmd application, it needs to stop and restart Tx port
+to take effect.
+
+Usage::
+
+    testpmd>set tx lldp on
+
 Limitations or Knowing issues
 -----------------------------
 
diff --git a/drivers/net/iavf/iavf_testpmd.c b/drivers/net/iavf/iavf_testpmd.c
new file mode 100644
index 0000000000..07aac07fc3
--- /dev/null
+++ b/drivers/net/iavf/iavf_testpmd.c
@@ -0,0 +1,81 @@ 
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2010-2016 Intel Corporation.
+ */
+
+#include <stdlib.h>
+
+#include <rte_pmd_iavf.h>
+
+#include <cmdline_parse_num.h>
+#include <cmdline_parse_string.h>
+
+#include "iavf.h"
+#include "testpmd.h"
+#include "iavf_rxtx.h"
+
+struct cmd_enable_tx_lldp_result {
+	cmdline_fixed_string_t set;
+	cmdline_fixed_string_t tx;
+	cmdline_fixed_string_t lldp;
+	cmdline_fixed_string_t what;
+};
+
+static cmdline_parse_token_string_t cmd_enable_tx_lldp_set =
+	TOKEN_STRING_INITIALIZER(struct cmd_enable_tx_lldp_result,
+		set, "set");
+static cmdline_parse_token_string_t cmd_enable_tx_lldp_tx =
+	TOKEN_STRING_INITIALIZER(struct cmd_enable_tx_lldp_result,
+		tx, "tx");
+static cmdline_parse_token_string_t cmd_enable_tx_lldp_lldp =
+	TOKEN_STRING_INITIALIZER(struct cmd_enable_tx_lldp_result,
+		lldp, "lldp");
+static cmdline_parse_token_string_t cmd_enable_tx_lldp_what =
+	TOKEN_STRING_INITIALIZER(struct cmd_enable_tx_lldp_result,
+		what, "on#off");
+
+static void
+cmd_enable_tx_lldp_parsed(void *parsed_result,
+	__rte_unused struct cmdline *cl, __rte_unused void *data)
+{
+	struct cmd_enable_tx_lldp_result *res = parsed_result;
+	const struct rte_mbuf_dynfield iavf_tx_lldp_dynfield = {
+		.name = IAVF_TX_LLDP_DYNFIELD,
+		.size = sizeof(uint8_t),
+		.align = __alignof__(uint8_t),
+		.flags = 0
+	};
+	int offset;
+
+	if (strncmp(res->what, "on", 2) == 0) {
+		offset = rte_mbuf_dynfield_register(&iavf_tx_lldp_dynfield);
+		printf("rte_pmd_iavf_tx_lldp_dynfield_offset: %d", offset);
+		if (offset < 0)
+			fprintf(stderr,
+				"rte mbuf dynfield register failed, offset: %d", offset);
+	}
+}
+
+static cmdline_parse_inst_t cmd_enable_tx_lldp = {
+	.f = cmd_enable_tx_lldp_parsed,
+	.data = NULL,
+	.help_str = "set iavf tx lldp on|off",
+	.tokens = {
+		(void *)&cmd_enable_tx_lldp_set,
+		(void *)&cmd_enable_tx_lldp_tx,
+		(void *)&cmd_enable_tx_lldp_lldp,
+		(void *)&cmd_enable_tx_lldp_what,
+		NULL,
+	},
+};
+
+static struct testpmd_driver_commands iavf_cmds = {
+	.commands = {
+	{
+		&cmd_enable_tx_lldp,
+		"set tx lldp (on|off)\n"
+		"    Set iavf Tx lldp packet(currently only supported on)\n\n",
+	},
+	{ NULL, NULL },
+	},
+};
+TESTPMD_ADD_DRIVER_COMMANDS(iavf_cmds)
diff --git a/drivers/net/iavf/meson.build b/drivers/net/iavf/meson.build
index a6ce2725c3..83aebd5596 100644
--- a/drivers/net/iavf/meson.build
+++ b/drivers/net/iavf/meson.build
@@ -8,6 +8,9 @@  endif
 cflags += ['-Wno-strict-aliasing']
 
 includes += include_directories('../../common/iavf')
+
+testpmd_sources = files('iavf_testpmd.c')
+
 deps += ['common_iavf', 'security', 'cryptodev']
 
 sources = files(