bcm4908: start work on images for devices using U-Boot

New BCM4908 family based routers will use U-Boot bootloader. That will
require using a totally different firmware format. Kernel has to be put
in a FIT image.

OpenWrt has some helpers for generating .its files but they don't fit
BCM4908 requirements and there is no simple way of extending any of
them. The best solution seems to be storing an .its template.

BCM4908 bootfs may:
1. contain extra binaries (other than kernel & DTB)
2. include multiple DTB files
3. store device specific U-Boot configurations with custom properties

Such setups are too complex to generate using shell script. Raw .its
file on the other hand seems quire clean & reasonable.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
This commit is contained in:
Rafał Miłecki 2021-11-03 18:12:05 +01:00
parent 29f12fefc0
commit a02c971dff
2 changed files with 36 additions and 0 deletions

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@ -6,6 +6,17 @@ include $(INCLUDE_DIR)/image.mk
DEVICE_VARS += ASUS_PRODUCTID ASUS_BUILD_NO ASUS_FW_REV ASUS_EXT_NO
DEVICE_VARS += NETGEAR_BOARD_ID NETGEAR_REGION
define Image/Prepare
cp bootfs-generic.its $(KDIR)/
endef
define Build/bootfs
cat $@ | $(STAGING_DIR_HOST)/bin/lzma e -eos -si -so > $@.tmp
mv $@.tmp $@
sed -i "s=\$${kernel}=$@=" $(KDIR)/bootfs-generic.its
PATH=$(LINUX_DIR)/scripts/dtc:$(PATH) mkimage -f $(KDIR)/bootfs-generic.its $(KDIR)/bootfs-generic.itb
endef
define Build/bcm4908asus
$(STAGING_DIR_HOST)/bin/bcm4908asus create -i $@ \
-p $(ASUS_PRODUCTID) -b $(ASUS_BUILD_NO) -f $(ASUS_FW_REV) \

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@ -0,0 +1,25 @@
// SPDX-License-Identifier: GPL-2.0-or-later OR MIT
/dts-v1/;
/ {
description = "OpenWrt bootfs image";
#address-cells = <1>;
images {
kernel {
description = "Linux kernel";
data = /incbin/("${kernel}");
type = "kernel";
os = "linux";
arch = "arm64";
compression = "lzma";
load = <0x80000>;
entry = <0x80000>;
hash-1 {
algo = "sha256";
};
};
};
};