ARM: at91: separate restart handler registration into SoC specific code ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

ARM: at91: consolidate phy reset functions ...

Many boards have the same ethernet phy reset function, so share the code
in a common function.
While at it remove the AT91_RSTC offset from the rstc register defines.
AT91_RSTC was the offset between the AT91_SYSTEM_BASE and the reset
controller.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

restart: replace reset_cpu with registered restart handlers ...

This replaces the reset_cpu() function which every SoC or board must
provide with registered handlers. This makes it possible to have multiple
reset functions for boards which have multiple ways to reset the machine.
Also boards which have no way at all to reset the machine no longer
have to provide a dummy reset_cpu() function.

The problem this solves is that some machines have external PMICs or
similar to reset the system which have to be preferred over the
internal SoC reset, because the PMIC can reset not only the SoC but also
the external devices.

To pick the right way to reset a machine each handler has a priority. The
default priority is 100 and all currently existing restart handlers are
registered with this priority. of_get_restart_priority() allows to retrieve
the priority from the device tree which makes it possible for boards to
give certain restart handlers a higher priority in order to use this one
instead of the default one.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

at91sam9: drop AT91_BASE_SYS for sdram controller ...

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

at91: fix reset ...

on at91sam9 you need to shutdown the sdram/ddr controler before reseting
when you boot from nand

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>