[U-Boot] [PATCH] tools: make imxheader size align on page size

[Stefano Babic]

Hi Stefan,

On 16/04/2014 15:29, stefan at agner.ch wrote:
> From: Stefan Agner <stefan at agner.ch>
> 
> The i.MX V2 headers total size is 0x7fc. The header is placed
> in front of the U-Boot binary which of course is aligned to
> text base. Hence the header starting point is not page
> aligned (e.g. at 0x3f400404). This is still a valid header,
> which boots fine using serial loader. However, the image
> fails to boot from NAND (tested on a VF61x SoC).
> 

Can you better explain this ? There is only one board in mainline with
vf610. CONFIG_SYS_TEXT_BASE is set to 0x3f008000. I cannot get the
offset in your example. Are you referring to NAND page ? But if the
header must be aligned with the NAND page, this is pretty bad because we
have to adjust the header depending on the selected NAND chip. I do not
see this limitation in the manual.

You have also added FCB to the image to flash into the NAND. Are you
sure that everything is fine there ?

As feeling, it seems that adding this integer you move the limit and you
constraint the SOC to read more data as before.

> Most parts of the header have a length of a multiply of 16
> bytes.The rest of the header is filled with 8 bytes long DCD
> data.

I do not understand this phrase. The header is mainly composed by 32 bit
fields. See the structure dcd_addr_data_t.

> Only the boot data header is 3 word long (12 bytes).
/ivt_header>

ivt_header is defined as 32bit integer. What are you meaning here with
boot data header ?

> This patch makes sure the whole image is exactly 0x800 by
> adding one padding word after the boot data header. Since
> the individual data structures are referenced by pointers,
> this still results in a valid i.MX V2 header while
> maintaining page alignment.
> 
> Signed-off-by: Stefan Agner <stefan at agner.ch>
> ---
> I'm not 100% sure wheather this is the right approach solving
> this issue. This works for me, also tested with DCD data.
> 
>  tools/imximage.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/imximage.h b/tools/imximage.h
> index 01f861e..b596fb1 100644
> --- a/tools/imximage.h
> +++ b/tools/imximage.h
> @@ -149,6 +149,7 @@ typedef struct {
>  typedef struct {
>  	flash_header_v2_t fhdr;
>  	boot_data_t boot_data;
> +	uint32_t reserved1;
>  	dcd_v2_t dcd_table;
>  } imx_header_v2_t;
>  

The patch does not clarify the issue. It hides the problem, because
adding this additional place you can boot your board, but without really
understand why. What does it happen if you add additional fields before
dcd_table ? If it continues to work, the header must not be aligned with
the NAND page. But again, doing this, let the SOC reading more bytes as
it does without this fix.

Best regards,
Stefano Babic

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