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Re: Big Endian au1550

To: Prashant Viswanathan <vprashant@echelon.com>
Subject: Re: Big Endian au1550
From: ppopov@embeddedalley.com
Date: Wed, 27 Apr 2005 20:57:23 -0700
Cc: 'Manish Lachwani' <mlachwani@mvista.com>, linux-mips@linux-mips.org
In-reply-to: <5375D9FB1CC3994D9DCBC47C344EEB590165465B@miles.echelon.echcorp.com>
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Prashant Viswanathan wrote:

Prashant Viswanathan wrote:

Is there a reason why the default configuration file doesn't support Big
Endian for the dbAu1550?

Even if I edit .config to set the endianness to "BIG" it seems to change
to
"Little Endian" every time a make is run.

Thanks
Prashant




In arch/mips/Kconfig,

config CPU_LITTLE_ENDIAN
       bool "Generate little endian code"
       default y if ACER_PICA_61 || CASIO_E55 || DDB5074 || DDB5476 ||
DDB5477 || MACH_DECSTATION
|| IBM_WORKPAD || LASAT || MIPS_COBALT || MIPS_ITE8172 || MIPS_IVR ||
SOC_AU1X00 || NEC_OSPREY || OLIVETTI_M700 || SNI_RM200_PCI ||
VICTOR_MPC30X || ZAO_CAPCELLA
       default n if MIPS_EV64120 || MIPS_EV96100 || MOMENCO_OCELOT ||
MOMENCO_OCELOT_G || SGI_IP22 || SGI_IP27 || SGI_IP32 || TOSHIBA_JMR3927
       help
         Some MIPS machines can be configured for either little or big
endian
         byte order. These modes require different kernels. Say Y if your
         machine is little endian, N if it's a big endian machine.

So, it appears that if you have SOC_AU1X00 set, it will always be
configured little endian.

Is there a reason for this?
It's the more common configuration.

Many months ago I was able to build a big-endian image and load it on my
dbAu1550 (also configured to be BE). I just decided to update and now I find
that it is almost as if it is not meant to be built BE.
BE should be fine too.  We should fix this in Kconfig.

Pete

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