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authorDzmitry Sankouski <dsankouski@gmail.com>2022-02-22 21:49:54 +0300
committerTom Rini <trini@konsulko.com>2022-04-04 19:02:03 -0400
commitd5c4ec4aa3aaa833cb535daa64a583a14304fc95 (patch)
tree0d5106a3e30ded64eed021c762039b48c8378e99 /doc
parentf8a1b33889a2ed880062d9960a68718463093de6 (diff)
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board: axy17lte: get board usable - add bootcmd and docs
U-boot is intended to replace linux kernel in android boot image(ABL), and it's FIT payload to replace initramfs file. The boot process is similar to boot image with linux: - android bootloader (ABL) unpacks android boot image - ABL sets `linux,initrd-start property` in chosen node in unpacked FDT - ABL sets x0 register to FDT address, and passes control to u-boot - u-boot reads x0 register, and stores it in `prevbl_fdt_addr` env variable - u-boot reads `linux,initrd-start` property, and stores it in `prevbl_initrd_start_addr` In this way, u-boot bootcmd relies on `prevbl_initrd_start_addr` env variable, and boils down to `bootm $prevbl_initrd_start_addr`. If more control on boot process is desired, pack a boot script in FIT image, and put it to default configuration What done: - Rearrange defconfig option order - Add CONFIG_SAVE_PREV_BL_* options - Doc updates: - remove wrong SBOOT memory corruption note, because memory is changed during u-boot bringup process, not by SBOOT - put payload on ramdisk place in abl boot image creation step Signed-off-by: Dzmitry Sankouski <dsankouski@gmail.com>
Diffstat (limited to 'doc')
-rw-r--r--doc/board/samsung/axy17lte.rst15
1 files changed, 3 insertions, 12 deletions
diff --git a/doc/board/samsung/axy17lte.rst b/doc/board/samsung/axy17lte.rst
index e84fefe..b7f299d 100644
--- a/doc/board/samsung/axy17lte.rst
+++ b/doc/board/samsung/axy17lte.rst
@@ -66,26 +66,17 @@ and is therefore SBOOT's payload.
It may be pure u-boot (with loading u-boot's payload from flash in mind),
or u-boot + u-boot's payload.
-It should be kept in mind, that SBOOT binary patches it's payload after loading
-in address range 0x401f8550-0x401f9280. Given SBOOT loads payload to 0x40001000,
-a range of 0x1f7550-0x1f8280 (2061648-2065024) in a payload file
-will be corrupted after loading to RAM.
-
Creating payload file
"""""""""""""""""""""
- Assemble FIT image for your kernel
-- Create a file for u-boot payload ``touch sboot-payload``
-- Write zeroes till 0x200000 address to be sure SBOOT won't corrupt your info
- ``dd if=/dev/zero of=sboot-payload bs=$((0x200000)) count=1``
-- Write u-boot to the start of the payload ``dd if=<u-boot.bin path> of=sboot-payload``
-- Write FIT image to payload from 0x200000 address
- ``dd if=<FIT image path> of=sboot-payload seek=1 bs=2M``
Creating android boot image
"""""""""""""""""""""""""""
Once payload created, it's time for android image::
- mkbootimg --base 0x40000000 --kernel_offset 0x00000000 --ramdisk_offset 0x01000000 --tags_offset 0x00000100 --pagesize 2048 --second_offset 0x00f00000 --kernel <sboot-payload path> -o uboot.img
+ uboot=<path to u-boot.bin file>
+ ramdisk=<path to FIT payload file>
+ mkbootimg --base 0x40000000 --kernel_offset 0x00000000 --ramdisk_offset 0x01000000 --tags_offset 0x00000100 --pagesize 2048 --second_offset 0x00f00000 --kernel "$uboot" --ramdisk "$ramdisk" -o uboot.img
Note, that stock Samsung bootloader ignores offsets, set in mkbootimg.