How to set fw_env.config

Bernie Chen

Expert 2190 points

Hello TI

I want use fw_env.config to print u-boot enviroment variables in kernel userspace

but I don't know how to set value for each entry. Could you help me to fill the blank ?

Thank you.

u-boot/include/configs/am335x_evm.h

#define CONFIG_ENV_SIZE (128 << 10)

#define CONFIG_ENV_SECT_SIZE (4 << 10) /* 4 KB sectors */
#define CONFIG_ENV_OFFSET (768 << 10) /* 768 KiB in */

#define CONFIG_ENV_OFFSET 0x260000 /* environment starts here */

And How do I set fw_env.config?

MTD device name ----> ?

Device Offset -----> 0x260000??

Environment Size -----> ?

Flash sector size ------> ?

Thank you

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi Bernie,

I will forward this to the Linux experts.

0 Bernie Chen over 9 years ago in reply to Biser Gatchev-XID

Expert 2190 points

Hi Biser

I very appreciate your quickly reply.

BestRegards

Bernie

0 Yordan Kovachev over 9 years ago in reply to Bernie Chen

TI__Guru**** 161600 points

Hi Bernie,

In general you can get the information by using cat /proc/mtd.

If mtd is empty (no information about partitions), you should add CONFIG_MTD_ONENAND=y to your defconfig (or .config) file and rebuild your kernel. After this you should see information about partitions in nand in the /proc/mtd & in console output upon boot.

You can use the following linux guides:

http://elinux.org/U-boot_environment_variables_in_linux

http://labs.isee.biz/index.php/How_to_modify_the_uboot_environment_from_userspace

Best regards,

Yordan

0 Bernie Chen over 9 years ago in reply to Yordan Kovachev

Expert 2190 points

Hi Yordan

I can see information eventually about nand. but I have another question when I check cat /proc/mtd. Is that means u-boot, uImage and filesystem will be in the NAND partition? Thank you.

ps We boot from sd card.

0 Yordan Kovachev over 9 years ago in reply to Bernie Chen

TI__Guru**** 161600 points

Hi Bernie,

No you don't have u-boot, uImage and filesystem in the NAND, since you haven't flashed it. You will still be booting from sd card.

Best Regards,

Yordan

0 Bernie Chen over 9 years ago in reply to Yordan Kovachev

Expert 2190 points

Hi Yordan

1 I kind of know your explain,. That NAND just like EMMC, you can flash images into predefined partitions. Right?

2 So if I want to see default enviroment variables and user-supplied enviroment variables by ./fw_printenv, it must be

necessary that NAND u-boot partitions and u-boot env parttions need to have somting flashed into ? Right ?

Thank you very much.

BestRegards

Bernie

0 Yordan Kovachev over 9 years ago in reply to Bernie Chen

TI__Guru**** 161600 points

Bernie,

Bernie Chen said:

So if I want to see default enviroment variables and user-supplied enviroment variables by ./fw_printenv, it must be

necessary that NAND u-boot partitions and u-boot env parttions need to have somting flashed into ? Right ?

Thank you very much.

Yes you need to configure your u-boot to store the environment variables in NAND; in other words to define CONFIG_ENV_IS_IN_NAND

Best Regards,

Yordan

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How to set fw_env.config