[U-Boot] [GIT PULL] Zynq SoC changes

[Tom Rini]

On Fri, Jan 23, 2015 at 02:39:44PM +0100, Michal Simek wrote:
> On 01/23/2015 12:59 PM, Tom Rini wrote:
> > On Fri, Jan 23, 2015 at 10:02:04AM +0100, Michal Simek wrote:
> >> On 01/23/2015 02:05 AM, Tom Rini wrote:
> >>> On Wed, Jan 21, 2015 at 10:38:47AM +0100, Michal Simek wrote:
> >>>
> >>>> Hi Tom,
> >>>>
> >>>> please pull these patches to your tree. I have added there 2 patches
> >>>> for serial. Zynq is only one platform which is using this driver.
> >>>>
> >>>> Thanks,
> >>>> Michal
> >>>>
> >>>> The following changes since commit 92fa7f53f1f3f03296f8ffb14bdf1baefab83368:
> >>>>
> >>>>   Prepare v2015.01 (2015-01-12 09:39:08 -0500)
> >>>>
> >>>> are available in the git repository at:
> >>>>
> >>>>   git://www.denx.de/git/u-boot-microblaze.git zynq
> >>>>
> >>>> for you to fetch changes up to 025216f78e0dacd491908d0d76a3642630cd84dc:
> >>>>
> >>>>   serial: Extend structure comments with register offset (2015-01-21 10:36:36 +0100)
> >>>>
> >>>
> >>> I can't find a toolchain that doesn't give me something like:
> >>>  arm: +   zynq_zc70x
> >>> +(zynq_zc70x) arch/arm/cpu/armv7/zynq/lowlevel_init.S: Assembler messages:
> >>> +(zynq_zc70x) arch/arm/cpu/armv7/zynq/lowlevel_init.S:19: Error: selected processor doe
> >>> s not support ARM mode `fmrx r1,FPEXC'
> >>> +(zynq_zc70x) arch/arm/cpu/armv7/zynq/lowlevel_init.S:21: Error: selected processor does not support ARM mode `fmxr FPEXC,r1'
> >>> +(zynq_zc70x) make[3]: *** [arch/arm/cpu/armv7/zynq/lowlevel_init.o] Error 1
> >>> +(zynq_zc70x) make[2]: *** [arch/arm/cpu/armv7/zynq] Error 2
> >>> +(zynq_zc70x) make[1]: *** [arch/arm/cpu/armv7] Error 2
> >>> +(zynq_zc70x) make: *** [sub-make] Error 2
> >>>
> >>
> >> ok. I see. We have neon instructions enabled by default in xilinx toolchain.
> >> I have sent the patch which create and add
> >> PLATFORM_RELFLAGS += -mfpu=neon
> >> to config.mk.
> >>
> >> This should solve the problem with compilation.
> >> No problem to add this patch as the first in this serial not to break bisectability
> >> of the tree.
> > 
> > And we have a _really_ good reason for using FPU instructions, yes?
> 
> The description for doing that is in the patch but to be honest the biggest problem
> is that xilinx toolchain has FPU instructions enabled by default. Based on that fpu instructions
> can be used. For standard xilinx flow FSBL/u-boot - fsbl does that setting.
> For debug flow TCL + u-boot we are reaching this issue.
> 
> Maybe the second option can be to disable FPU instructions for u-boot compilation
> but then the problem is moved to next software which is designed to have FPU instructions
> enabled.
> That's why I think it is just better to enable it in u-boot.
> 
> Siva: Feel free to correct me if my understanding is not correct.

And for the record and clarity, we're still not actually using the FPU
in U-Boot nor intend to, just enabling normal workflows on these
platforms, right?

-- 
Tom
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