Hi,
I have made a boot menu for amlogic devices so it can boot multiple OS and the user can choose the OS to boot after powering on the device.
The project works flawlessly, but, I want to ditch the amlogic kernel 3.14.29 and use the mainline kernel instead. But I have two problems
1- u-boot tools (fw_printenv and fw_setenv) don’t work since the the /dev/env no longer exist in mainline Linux.
2- Can’t set Ir remote since the /dev/amremote no longer exist in mainline linux
Have anyone tried to setup ir remote control and u-boot tools(fw_printenv and fw_setenv) using mainline Linux ?
PS: I don’t have khadas vim but since the project works on any amlogic board I thought I’d ask here
Thanks
2 Likes
numbqq
July 6, 2018, 11:13am
2
Hi moham96,
Yes, the mainline linux doesn’t have env partition any more, I ever tried to add Amlogic eMMC partition table, but need many patches and it’s not a good idea to add driver/amlogic folder to mainline linux.
By the way, the boot menu is on uart or HDMI screen?
Thanks.
numbqq:
Yes, the mainline linux doesn’t have env partition any more, I ever tried to add Amlogic eMMC partition table, but need many patches and it’s not a good idea to add driver/amlogic folder to mainline linux.
Can we use the /dev/mmcblk block device directly in the fw_env.config ? The default config has an example of that but I don’t know how to calculated the addresses
# Configuration file for fw_(printenv/setenv) utility.
# Up to two entries are valid, in this case the redundant
# environment sector is assumed present.
# Notice, that the "Number of sectors" is not required on NOR and SPI-dataflash.
# Futhermore, if the Flash sector size is ommitted, this value is assumed to
# be the same as the Environment size, which is valid for NOR and SPI-dataflash
# NOR example
# MTD device name Device offset Env. size Flash sector size Number of sectors
#/dev/mtd1 0x0000 0x4000 0x4000
#/dev/mtd2 0x0000 0x4000 0x4000
# MTD SPI-dataflash example
# MTD device name Device offset Env. size Flash sector size Number of sectors
#/dev/mtd5 0x4200 0x4200
#/dev/mtd6 0x4200 0x4200
# NAND example
#/dev/mtd0 0x4000 0x4000 0x20000 2
# Block device example
#/dev/mmcblk0 0xc0000 0x20000
# VFAT example
#/boot/uboot.env 0x0000 0x4000
# Amlogic NAND
/dev/nand_env 0x000000 0x10000 0x10000
# Amlogic eMMC
/dev/env 0x000000 0x10000 0x10000
The boot menu is on the framebuffer (HDMI) and the user select the OS to boot using the keyboard or the IR remote
Thanks
Gouwa
July 6, 2018, 1:16pm
4
Real great job, will you share the code to the open source community?
Good day!
Well, I’ve already shared them on armbian forums
Ok, I updated the boot manager so it is now more portable and added some convenience features as well. Be aware that it is not beginner friendly, you need at least some knowledge about writing and editing u-boot scripts, Uart cable is not needed but...
1 Like
You can use the following offsets to access the persistent u-boot environment on emmc:
For the Khadas Vim:
ubuntu@kvim:~$ cat /etc/fw_env.config
/dev/mmcblk1 0x7400000 0x10000
For the Khadas Vim2:
ubuntu@kvim2:~$ cat /etc/fw_env.config
/dev/mmcblk1 0x27400000 0x00010000
I’m interested to know how you have implement the menue. AfaIk u-boot does not support reading from keyboard. Have you published the source code?
1 Like
umiddelb:
You can use the following offsets to access the persistent u-boot environment on emmc:
For the Khadas Vim:
ubuntu@kvim:~$ cat /etc/fw_env.config
/dev/mmcblk1 0x7400000 0x10000
For the Khadas Vim2:
ubuntu@kvim2:~$ cat /etc/fw_env.config
/dev/mmcblk1 0x27400000 0x00010000
Unfortunately, as I said I don’t have any of khadas boards, so Do You mind telling me how you calculated those offsets so I can do the same for my board ?
for the menu part, I boot a tiny Linux kernel with a script that shows the menu. That’s why I need to use mainline kernel instead of the heavily patched amlogic one (I want to reduce the boot time and mainline kernel boot faster)
1 Like
There are two ways to find out the right offset and size of the u-boot environment.
If you have access to the u-boot sources, look into …/include/configs and pick the relevant settings for your board, like CONFIG_ENV_SECT_SIZE, CONFIG_ENV_SIZE, CONFIG_ENV_OFFSET.
If you don’t have access to the source files, you can still find the area which is used by the environment. During boot you can define an additional u-boot environment variable of your choice and store the environment via `saveenv´. When booting has finished you can copy the relevant area (usually the sectors from 0 to the start of the first (usable) partition) with
sudo dd if=/dev/... bs=512 count=... | hd | less
and use `/´ within less to search for your previously defined variable. The environment starts at a sector boundary, the first bytes are used for checksumming, the environment size is 4k multiplied by a power of two. Thera are not that many possible choices.
1 Like
Have you tried petitboot so far?
1 Like
Petitboot is a bootloader, I didn’t want to replace the bootloader because this will probably come with a lot of difficulties and disadvantages, Instead, I kept the u-boot untouched and made only a boot menu that will instruct u-boot to boot to a specific system.Bootmenu for amlogic devices
umiddelb:
If you don’t have access to the source files, you can still find the area which is used by the environment. During boot you can define an additional u-boot environment variable of your choice and store the environment via `saveenv´. When booting has finished you can copy the relevant area (usually the sectors from 0 to the start of the first (usable) partition) with
sudo dd if=/dev/... bs=512 count=... | hd | less
and use `/´ within less to search for your previously defined variable. The environment starts at a sector boundary, the first bytes are used for checksumming, the environment size is 4k multiplied by a power of two. Thera are not that many possible choices.
Well, I found the offset through UART during the boot up of u-boot:
mmc read lba=0x14000, blocks=0x400
start dts,buffer=0000000073ec8ff0,dt_addr=0000000073ec8ff0
parts: 11
00: logo 0000000002000000 1
01: recovery 0000000002000000 1
02: rsv 0000000000800000 1
03: tee 0000000000800000 1
04: crypt 0000000002000000 1
05: misc 0000000002000000 1
06: instaboot 0000000020000000 1
07: boot 0000000002000000 1
08: system 0000000040000000 1
09: cache 0000000020000000 2
10: data ffffffffffffffff 4
get_dtb_struct: Get emmc dtb OK!
overide_emmc_partition_table: overide cache
[mmc_get_partition_table] skip partition cache.
Partition table get from SPL is :
name offset size flag
===================================================================================
0: bootloader 0 400000 0
1: reserved 2400000 4000000 0
2: cache 6c00000 20000000 2
3: env 27400000 800000 0
4: logo 28400000 2000000 1
5: recovery 2ac00000 2000000 1
6: rsv 2d400000 800000 1
7: tee 2e400000 800000 1
8: crypt 2f400000 2000000 1
9: misc 31c00000 2000000 1
10: instaboot 34400000 20000000 1
11: boot 54c00000 2000000 1
12: system 57400000 40000000 1
13: data 97c00000 30c200000 4
mmc read lba=0x12000, blocks=0x2
mmc read lba=0x12002, blocks=0x2
mmc_read_partition_tbl: mmc read partition OK!
eMMC/TSD partition table have been checked OK!
mmc env offset: 0x27400000
I used offset 0x27400000 and size 800000 in hexdump and I can see the whole environment variables as such :
root@amlogic:~# dd if=/dev/mmcblk0 |hd -s 0x27400000 -n 800000check=get_reboo|mode};if test $| | |flash;fi; .fb_a|width=1920.fdt | |udisk; then run| |
But when I use the same addresses in the fw_env.config I can’t get it to work/dev/mmcblk0 0x27400000 0x800000
Looking at the u-boot source found this in the board config#define CONFIG_ENV_SIZE (64*1024)/dev/mmcblk0 0x27400000 0x10000
Petitboot isn’t a replacement for u-boot. Petitboot provides a Linux based boot menue and starts the target operating system via the kexec system call. It’s useful if you want to boot from devices which aren’t accessible via u-boot but via Linux (e.g. SATA ports).
Do you get any kind of error message? You might need to add the sector size, e.g.
/dev/mmcblk0 0x27400000 0x10000 0x100
Well, This is the first time I hear about petitboot, if I understand correctly kexec system call load the kernel into memory and execute it directly so in a sense it is a bootloader. Anyway I thought my approach is more reliable to work since all it does is inform u-boot which system to boot into and everything else is done in u-boot(kinda like other multiboot solutions on arm devices like raspberry pi noobs, except this is more flexible since we have u-boot which is not present on raspberry pi).
umiddelb:
Do you get any kind of error message? You might need to add the sector size, e.g.
/dev/mmcblk0 0x27400000 0x10000 0x100
No, I don’t get any error, fw_setenv execute without any output and when I check through printenv I see that the variable value was not changed.
This is strange, what happens if you define a new variable or delete an existing one?
For mmc backed devices, this value is more or less irrelevant, since these devices offer full random access. If fw_setenv/fw_printenv needs access to devices with paged access only (e.g. spi flash), this value is important.
I know. Sometimes it’s easier to have everything you need to boot an operating system in one partition only.
Your approach needs write access to the u-boot environment, which is OK for mmc backed devices. Some flash memory based storage devices support a limited number of write cycles only. In this case you might want to avoid unnecessary write access.
deleting existing variable or defining a new one doesn’t work either
numbqq
July 10, 2018, 6:53am
20
Hi moham96,
The following config works on VIM1 linux 4.17.3.
root@Khadas:~# cat /etc/fw_env.config
# Configuration file for fw_(printenv/setenv) utility.
# Up to two entries are valid, in this case the redundant
# environment sector is assumed present.
# Notice, that the "Number of sectors" is not required on NOR and SPI-dataflash.
# Futhermore, if the Flash sector size is ommitted, this value is assumed to
# be the same as the Environment size, which is valid for NOR and SPI-dataflash
# Block device example
/dev/mmcblk1 0x27400000 0x10000
Linux 4.17.3:
root@Khadas:~# uname -r
4.17.3
Thanks.
