[U-Boot] tegra: override compiler flags for low level init code

Override -march setting for tegra to -march=armv4t for files that are
necessary for low level init on tegra.

The recent change to use -march=armv7-a for armv7 caused a regression
on tegra because tegra starts boot on a arm7tdmi processor before
transferring control to the cortex-a9.  While still executing on the
arm7tdmi there are calls to getenv_ulong() and memset() that cause an
illegal instruction exception if compiled for armv7.

Signed-off-by: Allen Martin <amartin@nvidia.com>
---
 arch/arm/cpu/armv7/tegra2/config.mk |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

On 05/14/2012 05:14 PM, Allen Martin wrote:
> Override -march setting for tegra to -march=armv4t for files that are
> necessary for low level init on tegra.
> 
> The recent change to use -march=armv7-a for armv7 caused a regression
> on tegra because tegra starts boot on a arm7tdmi processor before
> transferring control to the cortex-a9.  While still executing on the
> arm7tdmi there are calls to getenv_ulong() and memset() that cause an
> illegal instruction exception if compiled for armv7.
> 
> Signed-off-by: Allen Martin <amartin@nvidia.com>

Tested-by: Stephen Warren <swarren@wwwdotorg.org>

(This seems to be necessary to use gcc-4.6.1, but not gcc-4.5.3. The
Whistler patches I just sent were tested with this fix in place)

On Mon, May 14, 2012 at 04:23:33PM -0700, Stephen Warren wrote:
> On 05/14/2012 05:14 PM, Allen Martin wrote:
> > Override -march setting for tegra to -march=armv4t for files that are
> > necessary for low level init on tegra.
> > 
> > The recent change to use -march=armv7-a for armv7 caused a regression
> > on tegra because tegra starts boot on a arm7tdmi processor before
> > transferring control to the cortex-a9.  While still executing on the
> > arm7tdmi there are calls to getenv_ulong() and memset() that cause an
> > illegal instruction exception if compiled for armv7.
> > 
> > Signed-off-by: Allen Martin <amartin@nvidia.com>
> 
> Tested-by: Stephen Warren <swarren@wwwdotorg.org>
> 
> (This seems to be necessary to use gcc-4.6.1, but not gcc-4.5.3. The
> Whistler patches I just sent were tested with this fix in place)

Hi Tom, could you pick this up in u-boot-tegra?  Without it tegra is
currently broken in both u-boot-tegra and u-boot gits depending on the
compiler you use. 

-Allen

On 06/04/2012 11:54 AM, Allen Martin wrote:
> On Mon, May 14, 2012 at 04:23:33PM -0700, Stephen Warren wrote:
>> On 05/14/2012 05:14 PM, Allen Martin wrote:
>>> Override -march setting for tegra to -march=armv4t for files that are
>>> necessary for low level init on tegra.
>>>
>>> The recent change to use -march=armv7-a for armv7 caused a regression
>>> on tegra because tegra starts boot on a arm7tdmi processor before
>>> transferring control to the cortex-a9.  While still executing on the
>>> arm7tdmi there are calls to getenv_ulong() and memset() that cause an
>>> illegal instruction exception if compiled for armv7.
>>>
>>> Signed-off-by: Allen Martin <amartin@nvidia.com>
>>
>> Tested-by: Stephen Warren <swarren@wwwdotorg.org>
>>
>> (This seems to be necessary to use gcc-4.6.1, but not gcc-4.5.3. The
>> Whistler patches I just sent were tested with this fix in place)
> 
> Hi Tom, could you pick this up in u-boot-tegra?  Without it tegra is
> currently broken in both u-boot-tegra and u-boot gits depending on the
> compiler you use. 

It's been there for a while, I believe, at least in u-boot-tegra/master.

On Mon, Jun 04, 2012 at 11:00:35AM -0700, Stephen Warren wrote:
> On 06/04/2012 11:54 AM, Allen Martin wrote:
> > Hi Tom, could you pick this up in u-boot-tegra?  Without it tegra is
> > currently broken in both u-boot-tegra and u-boot gits depending on the
> > compiler you use. 
> 
> It's been there for a while, I believe, at least in u-boot-tegra/master.

Ah you're right sorry, my remote was stale.  What's the next merge
window to get this into u-boot/master?  I imagine other people must be
running into this too.

-Allen