ARM: Factor out reusable psci_cpu_entry

_sunxi_cpu_entry can be converted completely into a reusable
psci_cpu_entry. Tegra124 will use it as well.

As with psci_disable_smp, also the enabling is designed to be overloaded
in cased SMP is not controlled via ACTLR.

CC: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Tested-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
index cdcdccd..7d89b43 100644
--- a/arch/arm/cpu/armv7/psci.S
+++ b/arch/arm/cpu/armv7/psci.S
@@ -165,6 +165,15 @@
 ENDPROC(psci_disable_smp)
 .weak psci_disable_smp
 
+ENTRY(psci_enable_smp)
+	mrc	p15, 0, r0, c1, c0, 1		@ ACTLR
+	orr	r0, r0, #(1 << 6)		@ Set SMP bit
+	mcr	p15, 0, r0, c1, c0, 1		@ ACTLR
+	isb
+	bx	lr
+ENDPROC(psci_enable_smp)
+.weak psci_enable_smp
+
 ENTRY(psci_cpu_off_common)
 	push	{lr}
 
@@ -184,4 +193,18 @@
 	bx	lr
 ENDPROC(psci_cpu_off_common)
 
+ENTRY(psci_cpu_entry)
+	bl	psci_enable_smp
+
+	bl	_nonsec_init
+
+	adr	r0, _psci_target_pc
+	ldr	r0, [r0]
+	b	_do_nonsec_entry
+ENDPROC(psci_cpu_entry)
+
+.globl _psci_target_pc
+_psci_target_pc:
+	.word	0
+
 	.popsection