[U-Boot] Question about fw_printenv settings

[Detlev Zundel <dzu@denx.de>]

Hi Joe,

> Hi,
>
> I have problems with fw_env.config in NOR flash.
> Would anyone please help me solve it? Thanks.
>
> In my board config:
>
> ifdef CONFIG_NAND
> #define CFG_NO_FLASH
> #define CONFIG_ENV_IS_IN_NAND           1
> #define CONFIG_ENV_OFFSET               0x400000         /* add for 2008.10 */
> #define CONFIG_ENV_OFFSET_REDUND        0x404000
> #define CONFIG_ENV_SIZE                 0x4000
> #else
> #define CONFIG_ENV_IS_IN_FLASH          1
> #define CONFIG_ENV_ADDR                 (CFG_FLASH_BASE + 0x000c0000)
> #define PHYS_FLASH_SIZE                 0x1000000        /* 16 MB */
> #define CONFIG_ENV_SIZE                 0x20000
> #define CONFIG_ENV_SECT_SIZE            0x20000
> #define CONFIG_ENV_ADDR_REDUND          (CONFIG_ENV_ADDR + CONFIG_ENV_SECT_SIZE)
> #endif

Maybe you want to reconsider these settings after fixing your current
problem.  The idea that we have an CONFIG_ENV_SIZE additionally to
CONFIG_ENV_SECT_SIZE is so that we can define an environment _smaller_
than a whole sector.  This speeds up U-Boot when calculating the CRC
over the environment.  With your settings, U-Boot will need to read the
whole 128k for this calculation.

> # cat /proc/mtd
> dev:    size   erasesize  name
> mtd0: 00dc0000 00020000 "Linux"
> mtd1: 00100000 00020000 "User"
> mtd2: 00100000 00020000 "Boot"

Are you sure these partitions are correct?  The sizes add to 15.75 MiB
whereas above a comment says 16 MiB nor flash.  Also the header above
says that the first environment is at the FLASH_BASE + 768k and the
second at FLASH_BASE + 896k.  If the partitions here are all on nor in
linear order, the environments would be somewhere in mtd0...

> My fw_env.config setting:
> /dev/mtd2              0x400000        0x20000         0x20000

How did you arrive at these settings?  The second column is the offset
into the mtd device.  So you put 4 MiB there although mtd2 is only 1
MiB.

> but it doesn't work :(
> #fw_printenv
> Read error on /dev/mtd2: Success