ARM: PSCI: Split out common stack setup code from psci_arch_init

Every platform has the same stack setup code in assembly as part of
psci_arch_init.

Move this out into a common separate function, psci_stack_setup, for
all platforms. This will allow us to move the remaining parts of
psci_arch_init into C code, or drop it entirely.

Also provide a stub no-op psci_arch_init for platforms that don't need
their own specific setup code.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

arch/arm/cpu/armv7/ls102xa/psci.S

@@ -111,16 +111,6 @@ psci_cpu_off:
 1:	wfi
 	b	1b
 
-.globl	psci_arch_init
-psci_arch_init:
-	mov	r6, lr
-
-	bl	psci_get_cpu_id
-	bl	psci_get_cpu_stack_top
-	mov	sp, r0
-
-	bx	r6
-
 	.globl psci_text_end
 psci_text_end:
 	.popsection

arch/arm/cpu/armv7/mx7/psci.S

@@ -9,22 +9,6 @@
 
 	.arch_extension sec
 
-	@ r1 = target CPU
-	@ r2 = target PC
-
-.globl	psci_arch_init
-psci_arch_init:
-	mov	r6, lr
-
-	bl	psci_get_cpu_id
-	bl	psci_get_cpu_stack_top
-	mov	sp, r0
-
-	bx	r6
-
-	@ r1 = target CPU
-	@ r2 = target PC
-
 .globl psci_cpu_on
 psci_cpu_on:
 	push	{lr}

arch/arm/cpu/armv7/nonsec_virt.S

@@ -49,8 +49,13 @@ _secure_monitor:
 	mcr	p15, 0, r5, c12, c0, 1
 	isb
 
-	@ Obtain a secure stack, and configure the PSCI backend
+	@ Obtain a secure stack
+	bl	psci_stack_setup
+
+	@ Configure the PSCI backend
+	push	{r0, r1, r2, ip}
 	bl	psci_arch_init
+	pop	{r0, r1, r2, ip}
 #endif
 
 #ifdef CONFIG_ARM_ERRATA_773022

arch/arm/cpu/armv7/psci.S

@@ -211,6 +211,24 @@ ENTRY(psci_get_cpu_stack_top)
 	bx	lr
 ENDPROC(psci_get_cpu_stack_top)
 
+@ {r0, r1, r2, ip} from _do_nonsec_entry(kernel_entry, 0, machid, r2) in
+@ arch/arm/lib/bootm.c:boot_jump_linux() must remain unchanged across
+@ this function.
+ENTRY(psci_stack_setup)
+	mov	r6, lr
+	mov	r7, r0
+	bl	psci_get_cpu_id		@ CPU ID => r0
+	bl	psci_get_cpu_stack_top	@ stack top => r0
+	mov	sp, r0
+	mov	r0, r7
+	bx	r6
+ENDPROC(psci_stack_setup)
+
+ENTRY(psci_arch_init)
+	mov	pc, lr
+ENDPROC(psci_arch_init)
+.weak psci_arch_init
+
 ENTRY(psci_cpu_entry)
 	bl	psci_enable_smp
 

arch/arm/cpu/armv7/sunxi/psci_head.S

@@ -44,22 +44,8 @@
 #define	GICD_BASE		(SUNXI_GIC400_BASE +  0x1000)
 #define	GICC_BASE		(SUNXI_GIC400_BASE +  0x2000)
 
-@ {r0, r1, r2, ip} from _do_nonsec_entry(kernel_entry, 0, machid, r2) in
-@ arch/arm/lib/bootm.c:boot_jump_linux() must remain unchanged across
-@ this function.
 ENTRY(psci_arch_init)
-	mov	r6, lr
+	b	sunxi_gic_init
-	mov	r7, r0
-	bl	psci_get_cpu_id		@ CPU ID => r0
-	bl	psci_get_cpu_stack_top	@ stack top => r0
-	sub	r0, r0, #4		@ Save space for target PC
-	mov	sp, r0
-	mov	r0, r7
-	mov	lr, r6
-
-	push	{r0, r1, r2, ip, lr}
-	bl	sunxi_gic_init
-	pop	{r0, r1, r2, ip, pc}
 ENDPROC(psci_arch_init)
 
 ENTRY(psci_text_end)

arch/arm/mach-tegra/psci.S

@@ -61,9 +61,6 @@ ENTRY(psci_arch_init)
 	ldrne	r7, [r5]
 	mcrne	p15, 0, r7, c14, c0, 0	@ write CNTFRQ to CPU1..3
 
-	bl	psci_get_cpu_stack_top	@ stack top => r0
-	mov	sp, r0
-
 	bx	r6
 ENDPROC(psci_arch_init)