zephyr-dom0-xt: Add vchan simple echo server

Add vchan simple echo server. Server opens channel and all incoming
data will be send back. Server will be enabled with option
CONFIG_VCHAN_SHELL_CMDS. Server introduces 2 commands:
    vchan start [domid]
      Start echo server. domid - The peer domain that will be connecting
      (0 by default)
    vchan stop
      Stop server
Updated README.rst with information about vchan echo server

Signed-off-by: Dmytro Semenets <[email protected]>
Reviewed-by: Grygorii Strashko <[email protected]>
Acked-by: Oleksii Moisieiev <[email protected]>
Acked-by: Volodymyr Babchuk <[email protected]>
Acked-by: Dmytro Firsov <[email protected]>
Reviewed-by: Artem Mygaiev <[email protected]>

CMakeLists.txt

@@ -27,3 +27,5 @@ else()
     target_sources(app PRIVATE src/dom_cfg/${BOARD}.c)
   endif()
 endif()
+
+target_sources_ifdef(CONFIG_VCHAN_SHELL_CMDS app PRIVATE src/vchan_cmds.c)

Kconfig

@@ -111,4 +111,29 @@ config DOM_COVERAGE_ENABLE
 	  Enable code coverage with GCOV and enable shell command to print GCOV
 	  dump "gcov dump" in console.
 
+config VCHAN_SHELL_CMDS
+	depends on SHELL
+	bool "Enable VCHAN echo server shell commands"
+	help
+	  Enable set of VCHAN echo server shell commands. All data incoming to
+	  channel created by this server will be send back. This is for test
+	  purposes. Server introduces 2 commands:
+	  vchan start [domid]
+	    Start echo server. domid - The peer domain that will be connecting
+	    (0 by default)
+	  vchan stop
+	    Stop server
+
+if VCHAN_SHELL_CMDS
+
+config VCHAN_ECHO_BUFFER_SIZE
+	int "Buffer size for echo server"
+	default 10
+
+config VCHAN_THREAD_STACK_SIZE
+	int "vchan echo server thread size"
+	default 2048
+
+endif #VCHAN_SHELL_CMDS
+
 source "Kconfig.zephyr"

README.rst

@@ -448,3 +448,33 @@ and execute the following command:
 .. code-block:: console
     ~ # ping -c 3 192.168.0.2
 
+RPI5 vchan simple echo server
+*****************************
+
+vchan echo server should be build with Kconfig configuration:
+
+.. code-block:: text
+    CONFIG_VCHAN_SHELL_CMDS=y
+
+Start echo server in zephyr console:
+
+.. code-block:: console
+    uart:~$ vchan start 1
+    Echo server openad at /local/domain/1/echo
+    Thread started
+
+On domd side vchan-node1 tool can be used to communicate with echo server. Send
+data to echo server:
+
+.. code-block:: console
+    root@raspberrypi5-domd:~# vchan-node1 client write 0 /local/domain/1/echo
+    seed=1709064173
+
+Enter data using keyboard. Stop this utility using Ctrl+C. Read data from
+server:
+
+.. code-block:: console
+    root@raspberrypi5-domd:~# vchan-node1 client read 0 /local/domain/1/echo
+    seed=1709068644
+
+Received (actually - entered early) symbols will be shown on console.

src/vchan_cmds.c

@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2024 EPAM Systems
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <domain.h>
+#include <vch.h>
+#include <zephyr/kernel.h>
+#include <zephyr/logging/log.h>
+#include <zephyr/shell/shell.h>
+
+LOG_MODULE_REGISTER(vchan_cmd);
+
+#define ECHO_SERVER_THREAD_PRIO    7
+#define PATH_TEMPLATE "/local/domain/%d/echo"
+#define THREAD_NAME "vchan_echo_server"
+
+static struct k_thread echo_thread;
+static struct k_thread *pecho_thread = NULL;
+static struct vch_handle handle;
+
+static K_THREAD_STACK_DEFINE(echo_thread_stack, CONFIG_VCHAN_THREAD_STACK_SIZE);
+static volatile int vchan_server_stop = 0;
+
+static void vchan_echo_server(void *p1, void *p2, void *p3)
+{
+	struct vch_handle *h = (struct vch_handle *)p1;
+	int size;
+	static char buf[CONFIG_VCHAN_ECHO_BUFFER_SIZE];
+
+	ARG_UNUSED(p2);
+	ARG_UNUSED(p3);
+	LOG_DBG("Server started\n");
+	while (!vchan_server_stop) {
+		size = vch_read(h, buf, sizeof(buf));
+		if (size > 0) {
+			vch_write(h, buf, size);
+		} else {
+			if (size < 0 && size != -ENOTCONN) {
+				LOG_ERR("vch_read returned %d\r", size);
+			}
+			k_sleep(K_MSEC(500));
+		}
+	}
+	LOG_DBG("Server stopped\n");
+	vch_close(h);
+}
+
+static int vchan_shell_start(const struct shell *sh, size_t argc, char **argv)
+{
+	int ret;
+	domid_t domid = 0;
+	static char path[PATH_MAX];
+
+	if (pecho_thread) {
+		shell_warn(sh, "Server already started");
+		return 1;
+	}
+	if (argv[1]) {
+		domid = atoi(argv[1]);
+	}
+	snprintf(path, PATH_MAX-1, PATH_TEMPLATE, domid);
+	ret = vch_open(domid, path, 10, 10, &handle);
+	if (ret) {
+		shell_error(sh, "vchan open error %d", ret);
+		goto exit;
+	}
+	shell_print(sh, "Echo server openad at %s", path);
+	vchan_server_stop = 0;
+	k_thread_create(&echo_thread, echo_thread_stack, K_THREAD_STACK_SIZEOF(echo_thread_stack),
+			vchan_echo_server, (void *)&handle, NULL, NULL,
+			ECHO_SERVER_THREAD_PRIO, 0, K_NO_WAIT);
+	pecho_thread = &echo_thread;
+	k_thread_name_set(pecho_thread, THREAD_NAME);
+
+exit:
+	return ret;
+}
+
+static int vchan_shell_stop(const struct shell *sh, size_t argc, char **argv)
+{
+	if (!pecho_thread) {
+		shell_warn(sh, "Server not started");
+		return 0;
+	}
+	vchan_server_stop = 1;
+	if (k_thread_join(pecho_thread, K_MSEC(1000))) {
+		shell_error(sh, "Killing thread");
+		k_thread_abort(pecho_thread);
+	}
+	pecho_thread = NULL;
+	return 0;
+}
+
+SHELL_STATIC_SUBCMD_SET_CREATE(
+	subcmd_vchan,
+	SHELL_CMD_ARG(start, NULL,
+		      "start echo server.\n"
+		      "\tUsage:\n"
+		      "\tvchan start [domid]\n",
+		      vchan_shell_start, 0, 1),
+	SHELL_CMD_ARG(stop, NULL,
+		      "stop server.\n",
+		      vchan_shell_stop, 0, 0),
+	SHELL_SUBCMD_SET_END);
+
+SHELL_CMD_ARG_REGISTER(vchan, &subcmd_vchan, "VCHAN commands", NULL, 2, 0);