[U-Boot] [PATCH] env_mmc: fix buffer allocation for armv7

[Tom Rini]

On Mon, Oct 07, 2013 at 07:34:24AM +0200, Wolfgang Denk wrote:
> Dear Tom,
> 
> In message <20131006204214.GO15917 at bill-the-cat> you wrote:
> > 
> > > Why do you hesitate to use the stack?
> > 
> > Mainly to allow us to work in restricted stack areas like SPL where we
> > simply may not have that much space available.
> 
> But malloc() is drawing from the very same resource as the stack, even
> more so: with a buffer on the stack, the memory isfreed completeky
> upon return from the fucntion, with no reminders left.  With malloc()
> you need to statically allocate the malloc pool size for the whole
> runtime, and allocating the buffers may fragment tha area, so even
> after freeing the buffers there is less space left for other purposes.
> 
> Especially in memory-tight situations you want to avoid malloc().

Ah, but in these cases we don't have stack room, period.  We have a
malloc pool.  So unless we make SPL move its stack pointer into DDR from
wherever we set the initial one to, the other option here is to just
restrict real env support to NOR (and we already don't allow embedded
env, since that's embedded within U-Boot, not SPL).

> 
> Best regards,
> 
> Wolfgang Denk
> 
> -- 
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-- 
Tom
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