[ARM] 2787/2: PXA27x low power modes support

Patch from Todd Poynor

Add symbols for PXA2xx PWRMODE register M field that selects low-power
mode, replace unadorned constants.  Honor power mode parameter of
pxa_cpu_suspend(mode), no longer force to 3 (sleep).  Full Deep Sleep
low-power mode support for PXA27x is pending generic PM interfaces to
select more than 2 suspend-to-RAM-style power modes, but this is
expected soon. This can be hardcoded in the meantime by replacing the
pxa_cpu_suspend() parameter value.  From David Burrage and Todd Poynor.
Try #2 removes one of the register copies and moves the code to save the
pxa_cpu_suspend parameter to immediately surround the call that requires
the parameter value be preserved.

Signed-off-by: Todd Poynor <tpoynor@mvista.com>
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-pxa/sleep.S

@@ -28,7 +28,9 @@
 /*
  * pxa_cpu_suspend()
  *
- * Forces CPU into sleep state
+ * Forces CPU into sleep state.
+ *
+ * r0 = value for PWRMODE M field for desired sleep state
  */
 
 ENTRY(pxa_cpu_suspend)
@@ -53,6 +55,7 @@ ENTRY(pxa_cpu_suspend)
 	mov	r10, sp
 	stmfd	sp!, {r3 - r10}
 
+	mov r5, r0				@ save sleep mode
 	@ preserve phys address of stack
 	mov	r0, sp
 	bl	sleep_phys_sp
@@ -66,7 +69,7 @@ ENTRY(pxa_cpu_suspend)
 	@ (also workaround for sighting 28071)
 
 	@ prepare value for sleep mode
-	mov	r1, #3				@ sleep mode
+	mov	r1, r5				@ sleep mode
 
 	@ prepare pointer to physical address 0 (virtual mapping in generic.c)
 	mov	r2, #UNCACHED_PHYS_0