[U-Boot] Cache alignment warnings on Tegra (ARM)
Marek Vasut
marex at denx.de
Tue Sep 18 21:36:18 CEST 2012
Dear Thierry Reding,
[...]
> > Sure, but after you apply the bounce buffer, you can safely invalidate
> > the whole cacheline, so align it up and be done with it.
>
> That's what I proposed to do last time around but it was NAK'ed.
By who?
> At the
> time I didn't ensure that the buffer was actually big enough, which is
> why people didn't like it (data on the stack after the DMA buffer might
> be invalidated as well).
Correct, thus the bounce buffer.
> > > This is by no means Tegra specific. In fact every board that has proper
> > > cache invalidation support should expose this problem.
> >
> > Yea of course, the arm926ejs had this trouble too, see the mxs MMC driver
> > and arm926 cache.c
>
> I suppose we could do something like this as well. If we make sure that
> the buffer is properly aligned and and sized, we could pass the aligned
> end address to invalidate_dcache_range().
>
> Thierry
Best regards,
Marek Vasut
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