[LEDE-DEV] RFC: files included in initramfs images (was: [PATCH] ramips: enable ramdisk for mt7621)

[Daniel Golle]

Hi Paul,

I've merged your patch, however, it looks like the buildbot process
still doesn't generate the desired image (despite our tests and success
we've seen earlier). This is because the ubnt-erx-factory-image build
artifact cannot work in the ImageBuilder and I've converted it into
a nicer and more compact variant (see patch below).
However, it still doesn't work for a rather odd and not as easy to fix
reason:
The resulting initramfs-kernel.bin as found on
http://downloads.lede-project.org/snapshots/targets/ramips/mt7621/lede-ramips-mt7621-ubnt-erx-initramfs-kernel.bin
is 3427 KB in size -- however, the Er-X allows only up to 3072 KB.
This is because (other than the rootfs) the initramfs is still not
generated individually for each board but rather contains all packages
needed for all boards in the same subtarget: on MT7621 this includes
several WiFi drivers and lots of things you usually won't ever need
on the Er-X.

Hence I suggest to change the way to initramfs is generated in general:
Create a second rootfs for initramfs and have only a very minimal and
not board-specific set of packages installed there. Maybe this could
also include stuff usually only needed during recovery/rescue/factory
situations such as a minimal web-interface which allows flashing the
'real' LEDE firmware.
To control the initramfs behaviour of the build-system we could
introduce a new config variable such as
CONFIG_TARGET_ROOTFS_INITRAMFS_MINIMAL which defaults to y
but can be disabled if people actually want the whole usual rootfs
being included in the initrd as well.
And we could have CONFIG_TARGET_ROOTFS_INITRAMFS_MINIMAL_EXTRA_PACKAGES
to allow including packages which aren't part of the normal rootfs.

I'd like to hear some opinion about that from Felix, John, Matthias,
Jo-Philipp, Hauke, Yousong, et al. before I get started to implement
this because it's a quite drastic change...


Cheers


Daniel




diff --git a/target/linux/ramips/image/mt7621.mk b/target/linux/ramips/image/mt7621.mk
index b57552a6f4..c9b2e537d4 100644
--- a/target/linux/ramips/image/mt7621.mk
+++ b/target/linux/ramips/image/mt7621.mk
@@ -3,27 +3,19 @@
 #
 
 define Build/ubnt-erx-factory-image
-	if [ -e $(KDIR)/tmp/$(KERNEL_INITRAMFS_IMAGE) -a "$$(stat -c%s $@)" -lt "$(KERNEL_SIZE)" ]; then \
-		echo '21001:6' > $(1).compat; \
-		$(TAR) -cf $(1) --transform='s/^.*/compat/' $(1).compat; \
-		\
-		$(TAR) -rf $(1) --transform='s/^.*/vmlinux.tmp/' $(KDIR)/tmp/$(KERNEL_INITRAMFS_IMAGE); \
-		mkhash md5 $(KDIR)/tmp/$(KERNEL_INITRAMFS_IMAGE) > $(1).md5; \
-		$(TAR) -rf $(1) --transform='s/^.*/vmlinux.tmp.md5/' $(1).md5; \
-		\
-		echo "dummy" > $(1).rootfs; \
-		$(TAR) -rf $(1) --transform='s/^.*/squashfs.tmp/' $(1).rootfs; \
-		\
-		mkhash md5 $(1).rootfs > $(1).md5; \
-		$(TAR) -rf $(1) --transform='s/^.*/squashfs.tmp.md5/' $(1).md5; \
-		\
-		echo '$(BOARD) $(VERSION_CODE) $(VERSION_NUMBER)' > $(1).version; \
-		$(TAR) -rf $(1) --transform='s/^.*/version.tmp/' $(1).version; \
-		\
-		$(CP) $(1) $(BIN_DIR)/; \
-	else \
-		echo "WARNING: initramfs kernel image too big, cannot generate factory image" >&2; \
-	fi
+	rm -rf $@.uImage $@.compat $@.rootfs $@.md5 $@.version
+	mv $@ $@.uImage
+	echo '21001:6' > $@.compat
+	$(TAR) -cf $@ --transform='s/^.*/compat/' $@.compat
+	$(TAR) -rf $@ --transform='s/^.*/vmlinux.tmp/' $@.uImage
+	mkhash md5 $@.uImage > $@.md5
+	$(TAR) -rf $@ --transform='s/^.*/vmlinux.tmp.md5/' $@.md5
+	echo "dummy" > $@.rootfs
+	$(TAR) -rf $@ --transform='s/^.*/squashfs.tmp/' $@.rootfs
+	mkhash md5 $@.rootfs > $@.md5
+	$(TAR) -rf $@ --transform='s/^.*/squashfs.tmp.md5/' $@.md5
+	echo '$(BOARD) $(VERSION_CODE) $(VERSION_NUMBER)' > $@.version
+	$(TAR) -rf $@ --transform='s/^.*/version.tmp/' $@.version
 endef
 
 define Device/11acnas
@@ -166,10 +158,12 @@ TARGET_DEVICES += timecloud
 define Device/ubnt-erx
   DTS := UBNT-ERX
   FILESYSTEMS := squashfs
-  KERNEL_SIZE := 3145728
+  KERNEL_SIZE := 3072k
   KERNEL := $(KERNEL_DTB) | uImage lzma
   IMAGES := sysupgrade.tar
-  KERNEL_INITRAMFS := $$(KERNEL) | ubnt-erx-factory-image $(KDIR)/tmp/$$(KERNEL_INITRAMFS_PREFIX)-factory.tar
+  KERNEL_INITRAMFS := $(KERNEL_DTB) | uImage lzma | check-size $(KERNEL_SIZE) | ubnt-erx-factory-image
+  KERNEL_INITRAMFS_PREFIX = $$(IMAGE_PREFIX)-factory
+  KERNEL_INITRAMFS_SUFFIX := .tar
   IMAGE/sysupgrade.tar := sysupgrade-tar | append-metadata
   DEVICE_TITLE := Ubiquiti EdgeRouter X
   DEVICE_PACKAGES := -kmod-mt76 -kmod-mt7603 -kmod-mt76x2 -kmod-mt76-core -kmod-mac80211 -kmod-cfg80211 -wpad-mini -iwinfo




On Thu, May 04, 2017 at 12:47:34AM +0200, Paul Spooren wrote:
> Fixes #758
> 
> Signed-off-by: Paul Spooren <paul at spooren.de>
> ---
>  target/linux/ramips/mt7621/target.mk | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/linux/ramips/mt7621/target.mk b/target/linux/ramips/mt7621/target.mk
> index 121761f45f..d075acbf87 100644
> --- a/target/linux/ramips/mt7621/target.mk
> +++ b/target/linux/ramips/mt7621/target.mk
> @@ -4,7 +4,7 @@
>  
>  SUBTARGET:=mt7621
>  BOARDNAME:=MT7621 based boards
> -FEATURES+=usb rtc nand
> +FEATURES+=nand ramdisk rtc usb
>  CPU_TYPE:=24kc
>  
>  DEFAULT_PACKAGES += kmod-mt76
> -- 
> 2.11.0
> 
> 
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