[U-Boot] [PATCH] net: fec: Avoid MX28 bus sync issue

Wolfgang Denk wd at denx.de
Thu Sep 12 20:53:49 CEST 2013


Dear Fabio Estevam,

In message <CAOMZO5BY6kDOCoWn_SRwhPE7ssMjAReZ2bcFXGgFF-_Wrdgo0g at mail.gmail.com> you wrote:
>
> > It makes perfect sense to allocate variable with function scope only
> > on the stack.  That's what the stack has been invented for.
> 
> This buffer in the fec driver will be used in DMA transfer, so maybe
> that's the reason we should use malloc instead of using the stack?

What has DMA to do with that?  We're talking about alignment only.

> At least in the kernel, we don't use stack for DMA buffers.

Yes, but them, the kernel uses a much more complicated memory setup,
with somewhat different mappings for different regions.  We don't do
that - or do we?  IMO we use a single mapping for the whole RAM ?

Best regards,

Wolfgang Denk

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