[U-Boot] __mmc_get_env_addr() is not being called?

[Stefano Babic <sbabic@denx.de>]

On 16/12/2011 06:54, Shawn Guo wrote:
> Hi,
> 

Hi Shawn,

> I'm running v2011.12-rc1 (with one missing usdhc patch applied) on
> mx6qarm2 board, and seeing a problem.  When I install u-boot on a
> blank SD card, it boots fine with messge "*** Warning - bad CRC,
> using default environment" seen as expected.  But once I run command
> 'save' to write envs to the card, the card stop booting.
> 
> I tracked the issue a little bit, and found __mmc_get_env_addr() does
> not get called at all.  Therefore when I run 'save' for the first time,
> the envs are written to offset 0 of the card, which in turn overwrites
> the boot image.
> 
> I have not figured out why it does.  But the following change fixes
> the problem for me.
> 
> diff --git a/common/env_mmc.c b/common/env_mmc.c
> index 8441c77..3832fe4 100644
> --- a/common/env_mmc.c
> +++ b/common/env_mmc.c
> @@ -46,13 +46,11 @@ DECLARE_GLOBAL_DATA_PTR;
>  #define CONFIG_ENV_OFFSET 0
>  #endif
> 
> -static int __mmc_get_env_addr(struct mmc *mmc, u32 *env_addr)
> +static int mmc_get_env_addr(struct mmc *mmc, u32 *env_addr)
>  {
>         *env_addr = CONFIG_ENV_OFFSET;
>         return 0;
>  }
> -int mmc_get_env_addr(struct mmc *mmc, u32 *env_addr)
> -       __attribute__((weak, alias("__mmc_get_env_addr")));
> 
> Any comment on why the change fixes the problem is appreciated.

The function is declared weak, this means that a specific architecture
could implement its own version. The reason why it does not work is that
there is a specific implementation in board/freescale/sdhc_boot.c, and
the mmc_get_env_addr() in this file is taken instead of the default when
CONFIG_ENV_IS_IN_MMC (as in our case) is set. Instead of your proposal,
we should surround mmc_get_env_addr() in sdhc_boot.c with something like
#ifndef CONFIG_MX6Q, or check if we can reuse this function, that really
does not use CONFIG_ENV_OFFSET at all.

I put Jason (board maintainer) in CC - Jason, what do mind ? Do you get
the same issue when you tested the board ?

Best regards,
Stefano Babic

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