[Buildroot] [PATCH 3/4] Create menu entry to select device creation method

[Yegor Yefremov <yegor_sub1@visionsystems.de>]

>> +choice
>> +	prompt "Device Creation"
>> +	default BR2_ROOTFS_DEVICE_CREATION_STATIC
> 
> I would probably name this "/dev management" or something similar. In
> my boards-cleanup work, I'm creating a new top-level "System
> configuration" menu. Maybe this should belong to this place instead,
> but this is something I can handle if I merge this patch into my
> boards-cleanup branch.

ACK
 
>> +config BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_MDEV
>> +	bool "Dynamic using mdev"
> 
> Maybe this should "select BR2_PACKAGE_BUSYBOX" ?

ACK

>>  config BR2_ROOTFS_DEVICE_TABLE
>> -       string "Path to the device table"
>> -       default "target/generic/device_table.txt"
>> -       help
>> -         Specify the location of a device table, that will be passed
>> -         to the makedevs utility to create all the special device
>> -         files in the target filesystem.
>> +	string "Path to the device table"
>> +	depends on BR2_ROOTFS_DEVICE_CREATION_STATIC
>> +	default "target/generic/device_table.txt"
>> +	help
>> +	 Specify the location of a device table, that will be passed
>> +	 to the makedevs utility to create all the special device
>> +	 files in the target filesystem.
> 
> Something odd here with the indentation. We should only see the new
> line "depends on BR2_ROOTFS_DEVICE_CREATION_STATIC" and no other change.

The indentation is already wrong in repository.
 
>> +ifneq ($(BR2_ROOTFS_DEVICE_CREATION_STATIC),y)
>> +	$(call KCONFIG_ENABLE_OPT,CONFIG_DEVTMPFS,$(@D)/.config)
>> +	$(call KCONFIG_ENABLE_OPT,CONFIG_DEVTMPFS_MOUNT,$(@D)/.config)
>> +endif
> 
> So devtmpfs is used even when mdev or udev are used ?

Why not? Otherwise you'll have to take care about /dev and fill it with devices.

>> index 0000000..943b73b
>> --- /dev/null
>> +++ b/package/busybox/S10mdev
>> @@ -0,0 +1,26 @@
>> +#!/bin/sh
>> +#
>> +# Start the mdev....
> 
> s/the//

ACK
 
>> +#
>> +
>> +case "$1" in
>> +  start)
>> + 	echo "Starting mdev..."
>> +	/sbin/mdev -s
> 
> This is not sufficient as far as I remember: this will only
> populate /dev with the existing devices. mdev also needs to be
> registered as a hotplug event handler by writing to some /proc/sys
> file. See mdev documentation for details (docs/mdev.txt in Busybox
> sources).

This can be done by filling the appropriate kernel option in .config UEVENT_HELPER_PATH.

>> +  stop)
>> +	echo -n "Stopping mdev..."
>> +	killall mdev
> 
> mdev is not a daemon, so there's no point in killing it.

ACK
 
>> diff --git a/package/busybox/busybox.mk b/package/busybox/busybox.mk
>> index b7f4740..d4b04a9 100644
>> --- a/package/busybox/busybox.mk
>> +++ b/package/busybox/busybox.mk
>> @@ -20,6 +20,19 @@ ifndef BUSYBOX_CONFIG_FILE
>>  	BUSYBOX_CONFIG_FILE = $(call qstrip,$(BR2_PACKAGE_BUSYBOX_CONFIG))
>>  endif
>>  
>> +# If mdev will be used for device creation enable it and copy S10mdev to /etc/init.d
>> +ifeq ($(BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_MDEV),y)
>> +define BUSYBOX_INSTALL_MDEV_SCRIPT
>> +	install -m 0755 package/busybox/S10mdev $(TARGET_DIR)/etc/init.d
>> +endef
>> +define BUSYBOX_SET_MDEV
>> +	$(call KCONFIG_ENABLE_OPT,CONFIG_MDEV,$(BUSYBOX_BUILD_CONFIG))
>> +	$(call KCONFIG_ENABLE_OPT,CONFIG_FEATURE_MDEV_CONF,$(BUSYBOX_BUILD_CONFIG))
>> +	$(call KCONFIG_ENABLE_OPT,CONFIG_FEATURE_MDEV_EXEC,$(BUSYBOX_BUILD_CONFIG))
>> +	$(call KCONFIG_ENABLE_OPT,CONFIG_FEATURE_MDEV_LOAD_FIRMWARE,$(BUSYBOX_BUILD_CONFIG))
>> +endef
>> +endif
>> +
>>  # If we have external syslogd, force busybox to use it
>>  ifeq ($(BR2_PACKAGE_SYSKLOGD),y)
>>  define BUSYBOX_SET_SYSKLOGD
>> @@ -114,6 +127,7 @@ define BUSYBOX_CONFIGURE_CMDS
>>  	$(BUSYBOX_SET_IPV6)
>>  	$(BUSYBOX_SET_RPC)
>>  	$(BUSYBOX_PREFER_STATIC)
>> +	$(BUSYBOX_SET_MDEV)
>>  	$(BUSYBOX_NETKITBASE)
>>  	$(BUSYBOX_NETKITTELNET)
>>  	@yes "" | $(MAKE) ARCH=$(KERNEL_ARCH) CROSS_COMPILE="$(TARGET_CROSS)" \
>> @@ -142,6 +156,7 @@ endif
>>  define BUSYBOX_INSTALL_TARGET_CMDS
>>  	$(BUSYBOX_INSTALL_BINARY)
>>  	-chmod a+rx $(TARGET_DIR)/usr/share/udhcpc/default.script
>> +	$(BUSYBOX_INSTALL_MDEV_SCRIPT)
>>  endef
> 
> This part sounds good to me.
> 
> Thomas