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

[Bill Pringlemeir]

On 23 Jan 2015, monstr at monstr.eu wrote:

> On 01/23/2015 02:05 AM, Tom Rini wrote:

>> 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)

>> On Wed, Jan 21, 2015 at 10:38:47AM +0100, Michal Simek wrote:

> 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.

I think you can add something like,

 .fpu neon-vfpv4 # or whatever FPU is appropriate.

to the lowlevel_init.S and then you can use the 'fmxr' instruction even
without compiler flags (and of course gas needs to know about it).  It
makes sense if the platform turns on floating point by default and you
need to disable it in lowlevel_init.S and don't want anyone else to be
using floating point.

... but I am not sure what exactly is going on so maybe it is not a good
fit here?

Fwiw,
Bill Pringlemeir.