[U-Boot] [PATCH v4 4/6] armv7: Use -march=armv7-a and thereby enable Thumb-2

Marek Vasut marek.vasut at gmail.com
Sat Jul 7 09:59:52 CEST 2012


Dear Aneesh V,

> Hi Marek,
> 
> On 07/06/2012 04:32 PM, Tetsuyuki Kobayashi wrote:
> > Hello,
> > 
> > On 2012/07/07, at 8:02, Marek Vasut wrote:
> >> Dear Aneesh V,
> >> 
> >>> Enable -march=armv7-a for armv7 platforms if the tool-chain
> >>> supports it. This in turn results in Thumb-2 code generated
> >>> for these platforms if CONFIG_SYS_THUMB_BUILD is enabled.
> >>> 
> >>> Signed-off-by: Aneesh V<aneesh at ti.com>
> >>> ---
> >> 
> >> For some reason, this patch breaks USB EHCI on mx51 efika boards. The
> >> board just freezes instead of detecting USB devices. Reverting this
> >> patch fixes the issue.
> >> 
> >> Note I use gcc 4.7.1 (!), might be compiler issue?
> >> 
> >> Tom, can you try on one of your beagle-dogs please? :)
> > 
> > Just for your information,
> > I doubt unaligned access causes this problem.
> > 
> > My investigation is here,
> > http://lists.denx.de/pipermail/u-boot/2012-June/127020.html
> > My patch
> > [PATCH] arm: armv7: add compile option	-mno-unaligned-access if 
available
> > http://lists.denx.de/pipermail/u-boot/2012-July/127260.html
> 
> This makes sense. You might want to try this patch. Also, to be sure
> that it's nothing to do with Thumb you can make sure you are not
> enabling CONFIG_SYS_THUMB_BUILD.

Ok, I think the patch should be applied then ?

but what if the option isn't available?

> best regards,
> Aneesh

Best regards,
Marek Vasut


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