For some time there have been repeated reports about build problems
with some ARM (cross) tool chains.  Especially issues about
(in)compatibility with the tool chain provided runtime support
library libgcc.a caused to add and support a private implementation
of such runtime support code in U-Boot.  A closer look at the code
indicated that some of these issues are actually home-made.  This
patch attempts to clean up some of the most obvious problems and make
building of U-Boot with different tool chains easier:

- Even though all ARM systems basicy used the same compiler options
  to select a specific ABI from the tool chain, the code for this was
  distributed over all cpu/*/config.mk files.  We move this one level
  up into lib_arm/config.mk instead.

- So far, we only checked if "-mapcs-32" was supported by the tool
  chain; if yes, this was used, if not, "-mabi=apcs-gnu" was
  selected, no matter if the tool chain actually understood this
  option.  There was no support for EABI conformant tool chains.
  This patch implements the following logic:

  1) If the tool chain supports
	"-mabi=aapcs-linux -mno-thumb-interwork"
     we use these options (EABI conformant tool chain).
  2) Otherwise, we check first if
	"-mapcs-32"
     is supported, and then check for
	"-mabi=apcs-gnu"
     If one test succeeds, we use the first found option.
  3) In case 2), we also test if "-mno-thumb-interwork", and use
     this if the test succeeds. [For "-mabi=aapcs-linux" we set
     "-mno-thumb-interwork" mandatorily.]

  This way we use a similar logic for the compile options as the
  Linux kernel does.

- Some EABI conformant tool chains cause external references to
  utility functions like raise(); such functions are provided in the
  new file lib_arm/eabi_compat.c

  Note that lib_arm/config.mk gets parsed several times, so we must
  make sure to add eabi_compat.o only once to the linker list.

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Dirk Behme <dirk.behme@googlemail.com>
Cc: Magnus Lilja <lilja.magnus@gmail.com>
Cc: Tom Rix <Tom.Rix@windriver.com>
Cc: Prafulla Wadaskar <prafulla@marvell.com>
Acked-by: Sergey Kubushyn <ksi@koi8.net>
Tested-by: Magnus Lilja <lilja.magnus@gmail.com>
Tested-by: Andrzej Wolski <awolski@poczta.fm>
Tested-by: Gaye Abdoulaye Walsimou <walsimou@walsimou.com>
Tested-by: Tom Rix <Tom.Rix@windriver.com>
Tested-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

For some reason the AT91rm9200 lowlevel init writes to a bunch of
reserved or read-only addresses.  All the boards seem to define the
value-to-be-written values as zero ... but they shouldn't actually
be writing *anything* there.

No documented erratum justifies these accesses.  It looks like maybe
some pre-release BDI-2000 setup code has been carried along by cargo
cult programming since at least late 2004 (per GIT history).

Here's a patch disabling what seems to be bogosity.  Tested on a
csb337; there were no behavioral changes.

Signed-off-by: David Brownell <david-b@pacbell.net>

on RM9200ek
Tested-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

Commit fcd3c87e made include/common.h usable by assembler code but
failed to update cpu/arm920t/start.S

Signed-off-by: Wolfgang Denk <wd@denx.de>

CSB337 boards originally shipped with MicroMonitor, not U-Boot;
and with a version using a different convention for recording
Ethernet addresses than anyone else.  To avoid breaking Linux
when it uses U-Boot, have it use the same convention on that
hardware.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

move s3c44b0 to arch_cpu_init and as noone use cpu_init remove it

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

all arm init the IRQ stack the same way
so unify it in lib_arm/interrupts.c and then call arch specific interrupt init

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

all arm boards except a few use the same cpu linker script
so move it to cpu/$(CPU)

that could be overwrite in following order
SOC
BOARD
via the corresponding config.mk

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>