shell: add an option for minimal default configuration

The default shell configuration has heavy flash and memory requirements,
requiring project maintainers to set many configuration options to "n"
to keep flash and memory requirements within reason.

This adds a new configuration option, CONFIG_SHELL_MINIMAL, which will
disable flash and memory heavy options by default, and allow project
maintainers to select/imply only the options they want.

On a quick test from an ARM board I'm working on, enabling this option
cut flash space requirements by ~8 KB, and memory requirements by ~1 KB.

Signed-off-by: Jack Rosenthal <[email protected]>

Author: jackrosenthal

doc/reference/shell/index.rst

@@ -32,10 +32,12 @@ interaction is required. This module is a Unix-like shell with these features:
 * Support for meta keys.
 * Kconfig configuration to optimize memory usage.
 
-Some of these features have a significant impact on RAM and flash usage,
-but many can be disabled when not needed.  A configuration that should
-produce the minimum useful feature set is in
-:zephyr_file:`samples/subsys/shell/shell_module/prj_minimal.conf`.
+.. note::
+	Some of these features have a significant impact on RAM and flash usage,
+	but many can be disabled when not needed.  To default to options which
+	favor reduced RAM and flash requirements instead of features, you should
+	enable :option:`CONFIG_SHELL_MINIMAL` and selectively enable just the
+	features you want.
 
 The module can be connected to any transport for command input and output.
 At this point, the following transport layers are implemented:

drivers/sensor/Kconfig

@@ -24,7 +24,7 @@ config SENSOR_SHELL
 	bool "Enable sensor shell"
 	depends on SHELL
 	select CBPRINTF_FP_SUPPORT
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  This shell provides access to basic sensor data.
 

samples/subsys/shell/shell_module/prj_minimal.conf

@@ -1,28 +1,12 @@
 CONFIG_PRINTK=y
 CONFIG_SHELL=y
-CONFIG_KERNEL_SHELL=n
+CONFIG_SHELL_MINIMAL=y
+CONFIG_SHELL_STACK_SIZE=1024
 CONFIG_SHELL_BACKEND_SERIAL=y
 CONFIG_OBJECT_TRACING=y
 CONFIG_THREAD_MONITOR=y
 CONFIG_INIT_STACKS=y
 CONFIG_BOOT_BANNER=n
 CONFIG_THREAD_NAME=y
 CONFIG_LOG=n
-CONFIG_SHELL_HISTORY=n
-CONFIG_SHELL_STACK_SIZE=1024
-CONFIG_SHELL_CMD_BUFF_SIZE=128
-CONFIG_SHELL_WILDCARD=n
-CONFIG_SHELL_DYNAMIC_CMDS=n
-CONFIG_SHELL_VT100_COLORS=n
-CONFIG_SHELL_HELP_ON_WRONG_ARGUMENT_COUNT=n
-CONFIG_SHELL_STATS=n
-CONFIG_SHELL_CMDS=n
-CONFIG_SHELL_HELP=n
-CONFIG_SHELL_TAB=n
-CONFIG_SHELL_METAKEYS=n
-CONFIG_SHELL_LOG_BACKEND=n
-CONFIG_KERNEL_SHELL=n
-CONFIG_DEVICE_SHELL=n
-CONFIG_DATE_SHELL=n
 CONFIG_CBPRINTF_NANO=y
-CONFIG_SENSOR_SHELL=n

samples/subsys/shell/shell_module/prj_minimal_rtt.conf

@@ -1,33 +1,16 @@
 CONFIG_PRINTK=y
 CONFIG_SHELL=y
-CONFIG_KERNEL_SHELL=n
+CONFIG_SHELL_MINIMAL=y
+CONFIG_SHELL_STACK_SIZE=1024
 CONFIG_SHELL_BACKEND_SERIAL=n
 CONFIG_OBJECT_TRACING=y
 CONFIG_THREAD_MONITOR=y
 CONFIG_INIT_STACKS=y
 CONFIG_BOOT_BANNER=n
 CONFIG_THREAD_NAME=y
 CONFIG_LOG=n
-CONFIG_SHELL_HISTORY=n
-CONFIG_SHELL_STACK_SIZE=1024
-CONFIG_SHELL_CMD_BUFF_SIZE=128
-CONFIG_SHELL_WILDCARD=n
-CONFIG_SHELL_DYNAMIC_CMDS=n
-CONFIG_SHELL_VT100_COLORS=n
-CONFIG_SHELL_HELP_ON_WRONG_ARGUMENT_COUNT=n
-CONFIG_SHELL_STATS=n
-CONFIG_SHELL_CMDS=n
 CONFIG_CONSOLE=y
-
-CONFIG_SHELL_HELP=n
-CONFIG_SHELL_TAB=n
-CONFIG_SHELL_METAKEYS=n
-CONFIG_SHELL_LOG_BACKEND=n
-CONFIG_KERNEL_SHELL=n
-CONFIG_DEVICE_SHELL=n
-CONFIG_DATE_SHELL=n
 CONFIG_CBPRINTF_NANO=y
-CONFIG_SENSOR_SHELL=n
 
 #enable RTT shell
 CONFIG_USE_SEGGER_RTT=y

subsys/shell/Kconfig

@@ -17,6 +17,14 @@ module-str = Shell
 source "subsys/logging/Kconfig.template.log_config"
 source "subsys/shell/Kconfig.backends"
 
+config SHELL_MINIMAL
+	bool "Default config to reduce flash and memory requirements"
+	help
+	  This is a meta-configuration option to significantly reduce the flash
+	  and memory requirements of the shell.  Enabling it will choose Kconfig
+	  defaults which favor reduced flash or memory requirements over extra
+	  features.
+
 config SHELL_STACK_SIZE
 	int "Shell thread stack size"
 	default 2520 if OPENTHREAD_SHELL
@@ -35,6 +43,7 @@ config SHELL_BACKSPACE_MODE_DELETE
 
 config SHELL_CMD_BUFF_SIZE
 	int "Shell command buffer size"
+	default 128 if SHELL_MINIMAL
 	default 256
 	help
 	  Maximum command size in bytes. One byte is reserved for the string
@@ -67,7 +76,7 @@ config SHELL_ARGC_MAX
 
 config SHELL_TAB
 	bool "Enable the Tab button support in shell"
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  Enable using the Tab button in the shell. The button
 	  can be used for prompting commands, or for autocompletion.
@@ -76,15 +85,15 @@ config SHELL_TAB
 config SHELL_TAB_AUTOCOMPLETION
 	bool "Enable commands autocompletion with the Tab button"
 	depends on SHELL_TAB
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  Enable commands and subcommands autocompletion with the Tab
 	  key. This function can be deactivated to save some flash.
 
 config SHELL_WILDCARD
 	bool "Enable wildcard support in shell"
 	select FNMATCH
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  Enables using wildcards: * and ? in the shell.
 
@@ -96,58 +105,59 @@ config SHELL_ECHO_STATUS
 
 config SHELL_VT100_COLORS
 	bool "Enable colors in shell"
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  If enabled VT100 colors are used in shell (e.g. print errors in red).
 
 config SHELL_METAKEYS
 	bool "Enable metakeys"
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  Enables shell meta keys: Ctrl+a, Ctrl+b, Ctrl+c, Ctrl+d, Ctrl+e,
 	  Ctrl+f, Ctrl+k, Ctrl+l, Ctrl+u, Ctrl+w, Alt+b, Alt+f
 	  Meta keys will not be active when shell echo is set to off.
 
 config SHELL_HELP
 	bool "Enable help message"
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  Enables formatting help message when requested with '-h' or '--help'.
 
 config SHELL_HELP_ON_WRONG_ARGUMENT_COUNT
 	bool "Enable printing help on wrong argument count"
 	depends on SHELL_HELP
-	default y
+	default y if !SHELL_MINIMAL
 
 config SHELL_HISTORY
 	bool "Enable history in shell"
-	default y
+	default y if !SHELL_MINIMAL
 	select RING_BUFFER
 	help
 	  Enable commands history. History can be accessed using up and down
 	  arrows or Ctrl+n and Ctrl+p meta keys.
 
 config SHELL_HISTORY_BUFFER
 	int "History buffer in bytes"
+	default 128 if SHELL_MINIMAL
 	default 512
 	depends on SHELL_HISTORY
 	help
 	  Number of bytes dedicated for storing executed commands.
 
 config SHELL_STATS
 	bool "Enable shell statistics"
-	default y
+	default y if !SHELL_MINIMAL
 
 config SHELL_CMDS
 	bool "Enable built-in commands"
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  Enable built-in commands like 'clear', 'history', etc.
 
 config SHELL_CMDS_RESIZE
 	bool "Enable resize command"
 	depends on SHELL_CMDS
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  By default shell assumes width of a terminal screen set to 80
 	  characters. Each time terminal screen width is changed resize command

subsys/shell/modules/Kconfig

@@ -5,7 +5,7 @@
 
 config KERNEL_SHELL
 	bool "Enable kernel shell"
-	default y
+	default y if !SHELL_MINIMAL
 	imply INIT_STACKS
 	imply THREAD_MONITOR
 	imply THREAD_NAME
@@ -16,13 +16,13 @@ config KERNEL_SHELL
 
 config DEVICE_SHELL
 	bool "Enable device shell"
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  This shell provides access to basic device data.
 
 config DATE_SHELL
 	bool "Enable date shell"
 	depends on POSIX_CLOCK
-	default y
+	default y if !SHELL_MINIMAL
 	help
 	  This shell provides access to date and time based on Unix time.

tests/subsys/shell/shell/shell_min.conf

@@ -2,37 +2,18 @@ CONFIG_ZTEST=y
 CONFIG_TEST_LOGGING_DEFAULTS=n
 
 CONFIG_SHELL=y
+CONFIG_SHELL_MINIMAL=y
 CONFIG_SHELL_BACKEND_DUMMY=y
 CONFIG_SHELL_BACKEND_SERIAL=n
 CONFIG_THREAD_NAME=y
 CONFIG_SHELL_STACK_SIZE=2048
-CONFIG_SHELL_CMD_BUFF_SIZE=128
 
 #using CBPRINTF_NANO decreases signigicantly Flash usage.
 CONFIG_CBPRINTF_NANO=y
 
 CONFIG_LOG=n
-#Shell features:
-CONFIG_SHELL_LOG_BACKEND=n
-CONFIG_SHELL_TAB=n
-CONFIG_SHELL_TAB_AUTOCOMPLETION=n
-CONFIG_SHELL_HELP=n
-CONFIG_SHELL_HELP_ON_WRONG_ARGUMENT_COUNT=n
-CONFIG_SHELL_HISTORY=n
-CONFIG_SHELL_CMDS=n
-CONFIG_SHELL_CMDS_RESIZE=n
-CONFIG_SHELL_CMDS_SELECT=n
-CONFIG_SHELL_WILDCARD=n
-CONFIG_SHELL_METAKEYS=n
-CONFIG_SHELL_VT100_COLORS=n
 
-CONFIG_KERNEL_SHELL=n
 CONFIG_OBJECT_TRACING=n
 CONFIG_THREAD_MONITOR=n
 CONFIG_INIT_STACKS=y
 CONFIG_BOOT_BANNER=n
-CONFIG_SHELL_STATS=n
-CONFIG_KERNEL_SHELL=n
-CONFIG_DEVICE_SHELL=n
-CONFIG_DATE_SHELL=n
-CONFIG_SENSOR_SHELL=n

tests/subsys/shell/shell/shell_min_cmds.conf

@@ -2,37 +2,20 @@ CONFIG_ZTEST=y
 CONFIG_TEST_LOGGING_DEFAULTS=n
 
 CONFIG_SHELL=y
+CONFIG_SHELL_MINIMAL=y
 CONFIG_SHELL_BACKEND_DUMMY=y
 CONFIG_SHELL_BACKEND_SERIAL=n
 CONFIG_THREAD_NAME=y
 CONFIG_SHELL_STACK_SIZE=2048
-CONFIG_SHELL_CMD_BUFF_SIZE=128
 
 #using CBPRINTF_NANO decreases signigicantly Flash usage.
 CONFIG_CBPRINTF_NANO=y
 
 CONFIG_LOG=n
 #Shell features:
-CONFIG_SHELL_LOG_BACKEND=n
-CONFIG_SHELL_TAB=n
-CONFIG_SHELL_TAB_AUTOCOMPLETION=n
-CONFIG_SHELL_HELP=n
-CONFIG_SHELL_HELP_ON_WRONG_ARGUMENT_COUNT=n
-CONFIG_SHELL_HISTORY=n
 CONFIG_SHELL_CMDS=y
-CONFIG_SHELL_CMDS_RESIZE=n
-CONFIG_SHELL_CMDS_SELECT=n
-CONFIG_SHELL_WILDCARD=n
-CONFIG_SHELL_METAKEYS=n
-CONFIG_SHELL_VT100_COLORS=n
 
-CONFIG_KERNEL_SHELL=n
 CONFIG_OBJECT_TRACING=n
 CONFIG_THREAD_MONITOR=n
 CONFIG_INIT_STACKS=y
 CONFIG_BOOT_BANNER=n
-CONFIG_SHELL_STATS=n
-CONFIG_KERNEL_SHELL=n
-CONFIG_DEVICE_SHELL=n
-CONFIG_DATE_SHELL=n
-CONFIG_SENSOR_SHELL=n

tests/subsys/shell/shell/shell_min_cmds_all.conf

@@ -2,37 +2,22 @@ CONFIG_ZTEST=y
 CONFIG_TEST_LOGGING_DEFAULTS=n
 
 CONFIG_SHELL=y
+CONFIG_SHELL_MINIMAL=y
 CONFIG_SHELL_BACKEND_DUMMY=y
 CONFIG_SHELL_BACKEND_SERIAL=n
 CONFIG_THREAD_NAME=y
 CONFIG_SHELL_STACK_SIZE=2048
-CONFIG_SHELL_CMD_BUFF_SIZE=128
 
 #using CBPRINTF_NANO decreases signigicantly Flash usage.
 CONFIG_CBPRINTF_NANO=y
 
 CONFIG_LOG=n
 #Shell features:
-CONFIG_SHELL_LOG_BACKEND=n
-CONFIG_SHELL_TAB=n
-CONFIG_SHELL_TAB_AUTOCOMPLETION=n
-CONFIG_SHELL_HELP=n
-CONFIG_SHELL_HELP_ON_WRONG_ARGUMENT_COUNT=n
-CONFIG_SHELL_HISTORY=n
 CONFIG_SHELL_CMDS=y
 CONFIG_SHELL_CMDS_RESIZE=y
 CONFIG_SHELL_CMDS_SELECT=y
-CONFIG_SHELL_WILDCARD=n
-CONFIG_SHELL_METAKEYS=n
-CONFIG_SHELL_VT100_COLORS=n
 
-CONFIG_KERNEL_SHELL=n
 CONFIG_OBJECT_TRACING=n
 CONFIG_THREAD_MONITOR=n
 CONFIG_INIT_STACKS=y
 CONFIG_BOOT_BANNER=n
-CONFIG_SHELL_STATS=n
-CONFIG_KERNEL_SHELL=n
-CONFIG_DEVICE_SHELL=n
-CONFIG_DATE_SHELL=n
-CONFIG_SENSOR_SHELL=n

tests/subsys/shell/shell/shell_min_cmds_resize.conf

@@ -2,37 +2,21 @@ CONFIG_ZTEST=y
 CONFIG_TEST_LOGGING_DEFAULTS=n
 
 CONFIG_SHELL=y
+CONFIG_SHELL_MINIMAL=y
 CONFIG_SHELL_BACKEND_DUMMY=y
 CONFIG_SHELL_BACKEND_SERIAL=n
 CONFIG_THREAD_NAME=y
 CONFIG_SHELL_STACK_SIZE=2048
-CONFIG_SHELL_CMD_BUFF_SIZE=128
 
 #using CBPRINTF_NANO decreases signigicantly Flash usage.
 CONFIG_CBPRINTF_NANO=y
 
 CONFIG_LOG=n
 #Shell features:
-CONFIG_SHELL_LOG_BACKEND=n
-CONFIG_SHELL_TAB=n
-CONFIG_SHELL_TAB_AUTOCOMPLETION=n
-CONFIG_SHELL_HELP=n
-CONFIG_SHELL_HELP_ON_WRONG_ARGUMENT_COUNT=n
-CONFIG_SHELL_HISTORY=n
 CONFIG_SHELL_CMDS=y
 CONFIG_SHELL_CMDS_RESIZE=y
-CONFIG_SHELL_CMDS_SELECT=n
-CONFIG_SHELL_WILDCARD=n
-CONFIG_SHELL_METAKEYS=n
-CONFIG_SHELL_VT100_COLORS=n
 
-CONFIG_KERNEL_SHELL=n
 CONFIG_OBJECT_TRACING=n
 CONFIG_THREAD_MONITOR=n
 CONFIG_INIT_STACKS=y
 CONFIG_BOOT_BANNER=n
-CONFIG_SHELL_STATS=n
-CONFIG_KERNEL_SHELL=n
-CONFIG_DEVICE_SHELL=n
-CONFIG_DATE_SHELL=n
-CONFIG_SENSOR_SHELL=n