U-Boot C2 env into eMMC

[mboehmer]

Hi,

 

maybe someone can give me a hint on this issue. I'm working on U-Boot v2017.11 currently, and just found out that on the Odroid C2 env settings are not changable inside the eMMC, but only at compile time for Uboot. I use an 16GB eMMC, not a sdcard.

So my question is: where and to what values have the following CONFIG_* parameters be set to have env settings changeable by setenv and saveenv in Uboot again?

 

#define CONFIG_ENV_SIZE                 (32 * SZ_1K)
#define CONFIG_ENV_OFFSET               (720 * SZ_1K)
#define CONFIG_SYS_MMC_ENV_DEV          1
#define CONFIG_SYS_MMC_ENV_PART         0

That's what I tried inside the include/configs/odroid-c2.h file, but it doesn't seem to work.

 

EDIT: the variables are not inside the image, after it has been written to eMMC by etcher. After a first reboot, and inside UBoot, I can "saveenv" the standard values and see them afterwards on the eMMC on the right position. I can also change and save them again.

What fails is using fw_printenv inside Linux. With the /etc/fw_env.config file

# <device>   <offset> <length>
/dev/mmcblk0 0xB4000   0x8000 

I get an error message like "Environment does not start on (erase) block boundary".

 

Any help / hint is appreciated.

 

Michael

[Igor]

7 hours ago, mboehmer said:

Any help / hint is appreciated.

People reported eMMC corruption with some variants of eMMC when using 2017.11 and mainline kernel. There are some dirty hacks in old u-boot regarding eMMCs. Perhaps it's related.

[mboehmer]

I just checked. In the image produced by compile.sh, there is no data no offset 0xb4000 (all 0x00).

After starting the C2 with this image, and manually "saveenv" in Uboot, I can readout the eMMC by dd, and see the envs correctly stored on offset 0xb4000.

 

This problem seems to be build related - compile.sh does not include the env section on the image in that case?

 

As you get a "CRC error" on the empty env section on booting, it may look like a corrupted memory area.

 

Any ideas on why the scripts does not include the env variables into the image?

 

EDIT: the env area must be 64kB aligned to fit the "erase page boundary". This allows to access the env from Linux by fw_printenv et.al.

# <device>   <offset> <length>
/dev/mmcblk0 0xc0000  0x8000

Still, the image for flashing the SDcard / eMMC does lack the initial settings.

 

EDIT2: I still get a CRC error with that file if accessing the env variables by fw_printenv.

 

If I do a

dd if=/dev/mmcblk0 of=y bs=512 skip=1536 count=64

(which is directly translated from fw_env.config file), I get the variables as they are printed in Uboot. So something seems still to be broken if accessing from fw_printenv, while it seems to work inside Uboot now.