[U-Boot] Breakage on gw_ventana

[Stefano Babic]

Hi Tim,

On 19/05/2016 15:48, Tim Harvey wrote:
> On Thu, May 19, 2016 at 6:02 AM, Stefano Babic <sbabic at denx.de> wrote:
>> Hi Tim,
>>
>> last changes break build for the gw_ventana board. In fact, in case
>> kernel is on a fs, we need to pass the name for kernel.  These two
>> defines should be set into gw_ventana.h:
>>
>>         CONFIG_SPL_FS_LOAD_KERNEL_NAME
>>         CONFIG_SPL_FS_LOAD_ARGS_NAME
>>
>> I could simply fix it, but it does not make sense without asking you :-)
>>
>> I have also seen that SPL for gw_ventana raises an exception because SPL
>> is bigger as the value set into imx6_spl.h (CONFIG_SPL_MAX_SIZE = 64Kb).
>> Anyway, CONFIG_SPL_MAX_SIZE for i.MX& iss too restrictive, and even the
>> mx6 with smaller SRAM has at least 128KB.
>>
> 
> Stefano,
> 
> Thanks for the heads-up. I have to admit I haven't looked at mainline
> u-boot on Ventana for quite some time - I'm still using a 2015-04
> branch with some patches on top that I haven't had time to mainline
> yet.
> 
> When you say 'last changes' was there something specific? Something
> must of grown the size of the SPL code quite a bit.

I think (but I am not sure) the biggest increase was done by allowing to
load image directly from filesystem, and then the size increased.

But I admit I did not take a closer look before - it looks like that
gw_ventana is the first to fail, just because it supports more methods
for booting. Most boards boots just from one media,

> 
> Your right that the smallest imx6 SRAM has 128KB although we have to
> be careful not to clobber the SRAM being used by the boot ROM. The
> reference manual indicates (IMX6*RM Figure 8-3) that there is only
> free area 68KB available after you carve out the 28KB reserved
> section, the 24KB MMU table, and the 8K stack. Admittedly I don't know
> if the BOOT rom code really uses all of these areas in such a way that
> it cant load the SPL into any of them.

I do not know as well - maybe some NXP developers can tell something more.

> Take a look at my comments at
> the top of include/configs/imx6_spl.h and let me know if you find
> something wrong with my analysis that led to a 64KB max.

Nothing wrong, but as far as I know in start.S cache and muu are turned
off, and they are turned on later again. This could let us to reuse
maybe the 24KB space previously set by the Bootrom

Best regards,
Stefano

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