zephyr: add shell implementation over USB CDC ACM

Author: benedekkupper

CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.19)
 
 project(c2usb
-    LANGUAGES CXX
+    LANGUAGES C CXX
 )
 
 if(DEFINED ENV{ZEPHYR_BASE})

README.md

@@ -42,6 +42,12 @@ The additional transport layers supported are:
 * BLE (HID over GATT Protocol)
 * I2C
 
+#### CDC-ACM - Serial Port
+
+The Abstract Control Model of Communications Device Class is fully implemented.
+Notably the notification endpoint can be marked as unused, skipping any hardware resource allocation,
+but keeping compatibility with all hosts.
+
 ### Platforms
 
 * NXP MCUs supported via `mcux_mac` (see [c2usb/port/nxp](c2usb/port/nxp))

c2usb/port/zephyr/CMakeLists.txt

@@ -19,3 +19,10 @@ target_sources_ifdef(CONFIG_C2USB_BLUETOOTH ${PROJECT_NAME}
     PRIVATE
         hid.cpp
 )
+target_sources_ifdef(CONFIG_SHELL_BACKEND_C2USB ${PROJECT_NAME}
+    PUBLIC
+        usb_shell.hpp
+    PRIVATE
+        usb_shell.c
+        usb_shell.cpp
+)

c2usb/port/zephyr/Kconfig

@@ -34,6 +34,8 @@ config C2USB_UDC_MAC_BUF_POOL_RESERVE
 
 endif # C2USB_UDC_MAC
 
+rsource "Kconfig.shell"
+
 endmenu
 
 choice STD_CPP

c2usb/port/zephyr/Kconfig.shell

@@ -0,0 +1,66 @@
+
+menuconfig SHELL_BACKEND_C2USB
+	bool "c2usb shell backend"
+	help
+	  Build c2usb shell backend.
+
+if SHELL_BACKEND_C2USB
+
+config SHELL_PROMPT_C2USB
+	string "Displayed prompt name"
+	default "c2usb:~$ "
+	help
+	  Displayed prompt name for c2usb backend. If prompt is set, the shell will
+	  send two newlines during initialization.
+
+config SHELL_BACKEND_C2USB_TX_BUFFER_SIZE
+	int "c2usb shell TX double buffer overall size"
+	range 128 256
+	default 256
+
+config SHELL_BACKEND_C2USB_RX_BUFFER_SIZE
+	int "c2usb shell RX double buffer overall size"
+	range 32 128
+	default 128
+
+module = SHELL_BACKEND_C2USB
+default-timeout = 100
+source "subsys/shell/Kconfig.template.shell_log_queue_timeout"
+
+default-size = 512
+source "subsys/shell/Kconfig.template.shell_log_queue_size"
+
+choice
+	prompt "Initial log level limit"
+	default SHELL_BACKEND_C2USB_LOG_LEVEL_DEFAULT
+
+config SHELL_BACKEND_C2USB_LOG_LEVEL_DEFAULT
+	bool "System limit (LOG_MAX_LEVEL)"
+
+config SHELL_BACKEND_C2USB_LOG_LEVEL_DBG
+	bool "Debug"
+
+config SHELL_BACKEND_C2USB_LOG_LEVEL_INF
+	bool "Info"
+
+config SHELL_BACKEND_C2USB_LOG_LEVEL_WRN
+	bool "Warning"
+
+config SHELL_BACKEND_C2USB_LOG_LEVEL_ERR
+	bool "Error"
+
+config SHELL_BACKEND_C2USB_LOG_LEVEL_NONE
+	bool "None"
+
+endchoice
+
+config SHELL_BACKEND_C2USB_LOG_LEVEL
+	int
+	default 0 if SHELL_BACKEND_C2USB_LOG_LEVEL_NONE
+	default 1 if SHELL_BACKEND_C2USB_LOG_LEVEL_ERR
+	default 2 if SHELL_BACKEND_C2USB_LOG_LEVEL_WRN
+	default 3 if SHELL_BACKEND_C2USB_LOG_LEVEL_INF
+	default 4 if SHELL_BACKEND_C2USB_LOG_LEVEL_DBG
+	default 5 if SHELL_BACKEND_C2USB_LOG_LEVEL_DEFAULT
+
+endif # SHELL_BACKEND_C2USB

c2usb/port/zephyr/usb_shell.c

@@ -0,0 +1,18 @@
+#if ((__has_include("zephyr/shell/shell.h")) && CONFIG_SHELL_BACKEND_C2USB)
+#include <zephyr/shell/shell.h>
+#include <zephyr/sys/atomic.h>
+
+struct shell_transport c2usb_shell_transport = {
+    .api = NULL,
+    .ctx = NULL,
+};
+
+SHELL_DEFINE(shell_c2usb, CONFIG_SHELL_PROMPT_C2USB, &c2usb_shell_transport,
+             CONFIG_SHELL_BACKEND_C2USB_LOG_MESSAGE_QUEUE_SIZE,
+             CONFIG_SHELL_BACKEND_C2USB_LOG_MESSAGE_QUEUE_TIMEOUT, SHELL_FLAG_OLF_CRLF);
+
+const struct shell* c2usb_shell_handle()
+{
+    return &shell_c2usb;
+}
+#endif