From 12a3e1ada06c702c403cf1eebb063ef7a34688cd Mon Sep 17 00:00:00 2001 From: Dzmitry Sankouski Date: Tue, 22 Feb 2022 21:49:52 +0300 Subject: arm: init: save previous bootloader data When u-boot is used as a chain-loaded bootloader (replacing OS kernel), previous bootloader leaves data in RAM, that can be reused. For example, on recent arm linux system, when chainloading u-boot, there are initramfs and fdt in RAM prepared for OS booting. Initramfs may be modified to store u-boot's payload, thus providing the ability to use chainloaded u-boot to boot OS without any storage support. Two config options added: - SAVE_PREV_BL_INITRAMFS_START_ADDR saves initramfs start address to 'prevbl_initrd_start_addr' environment variable - SAVE_PREV_BL_FDT_ADDR saves fdt address to 'prevbl_fdt_addr' environment variable Signed-off-by: Dzmitry Sankouski Cc: Tom Rini --- boot/Kconfig | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'boot') diff --git a/boot/Kconfig b/boot/Kconfig index 394b26f246..ec5b956490 100644 --- a/boot/Kconfig +++ b/boot/Kconfig @@ -1192,4 +1192,28 @@ config DEFAULT_FDT_FILE help This option is used to set the default fdt file to boot OS. +config SAVE_PREV_BL_FDT_ADDR + depends on ARM + bool "Saves fdt address, passed by the previous bootloader, to env var" + help + When u-boot is used as a chain-loaded bootloader (replacing OS kernel), + enable this option to save fdt address, passed by the + previous bootloader for future use. + Address is saved to `prevbl_fdt_addr` environment variable. + + If no fdt was provided by previous bootloader, no env variables + will be created. + +config SAVE_PREV_BL_INITRAMFS_START_ADDR + depends on ARM + bool "Saves initramfs address, passed by the previous bootloader, to env var" + help + When u-boot is used as a chain-loaded bootloader(replacing OS kernel), + enable this option to save initramfs address, passed by the + previous bootloader for future use. + Address is saved to `prevbl_initrd_start_addr` environment variable. + + If no initramfs was provided by previous bootloader, no env variables + will be created. + endmenu # Booting -- cgit v1.2.3