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>

Add the pxa3xx architecture, for pxa300, pxa310 and pxa320 SoCs.
This includes :
 - the registers
 - the cpu type
 - the reset source handling
 - a minimal set of clocks
 - pin control definitions
   In this last case, the big mfp-pxaxxx.h files were dropped, forcing
   board developers to use MFP_LPM_* macros cunningly.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Move reset_source detection and poweroff to pxa2xx.c, to prepare the
incoming pxa3xx reset_source detection.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Add the capability for the PXA architecture to poweroff.

As there is no true poweroff, ie. the power regulator is not available
for shut off from the core, the poweroff puts the SoC into a deep sleep
mode (mode 7), where almost no current is sunk.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Use PXA register RCSR to detect which is the reset cause.  When
triggering a reset, clear the former reset source first.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

The core support was brought by Marc and Sascha.
The cache choice was fixed by Luotao Fu.
Some gpio and devices addons were provided by Robert.

Signed-off-by: Luotao Fu <l.fu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>