Re: [PATCH] ARM: allow DEBUG_UNCOMPRESS for omap2plus

[Tony Lindgren <tony@atomide.com>]

* Stephen Warren <swarren@wwwdotorg.org> [130730 16:08]:
> On 07/30/2013 04:52 PM, Russell King - ARM Linux wrote:
> > On Tue, Jul 30, 2013 at 04:49:18PM -0600, Stephen Warren wrote:
> >> From: Stephen Warren <swarren@nvidia.com>
> >>
> >> DEBUG_UNCOMPRESS was previously disallowed for omap2plus due to
> >> omap2plus.S's use of .data, which is not allowed in the decompressor.
> >> Solve this by placing that data into .text when building the file into
> >> the decompressor. This relies on .text actually being writable in the
> >> decompressor, which it is in practice.
> > 
> > Unless you decide to use ZBOOT and flash the zImage.
> 
> I knew there had to be a catch:-)
> 
> I have no idea if ZBOOT is a use-case that's relevant to OMAP?
> 
> On Tegra at least (the same issue applies to the other patch I just
> sent), that use-case is almost impossible; even if the boot ROM directly
> booted a kernel, the boot ROM is hard-coded to copy whatever it's
> booting to SDRAM first, although I suppose if that was a boot-loader it
> could just jump back to a ROM location. That said, NOR flash is
> extremely rare on Tegra. So, I don't know if we care about this issue.
> 
> Is it reasonable to just say "If you use ZBOOT, don't enable
> DEBUG_UNCOMPRESS"? Perhaps these patches should not completely remove
> the !DEBUG_TEGRA_UART from config DEBUG_UNCOMPRESS, but instead say:
> 
> default y if DEBUG_LL && (!DEBUG_TEGRA_UART || !ZBOOT)?

I think we're best off removing the remaining uncompress code
configured port detection features as the port properties are now
defined in kconfig anyways. That simplifies the code quite a bit.

Regards,

Tony