mx7: psci: add basic psci support

1. add basic psci support for imx7 chip.
2. support cpu_on and cpu_off.
3. switch to non-secure mode when boot linux kernel.
4. set csu allow accessing all peripherial register in non-secure mode.

Signed-off-by: Frank Li <Frank.Li@freescale.com>
Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
diff --git a/arch/arm/cpu/armv7/mx7/psci.S b/arch/arm/cpu/armv7/mx7/psci.S
new file mode 100644
index 0000000..34c6ab3
--- /dev/null
+++ b/arch/arm/cpu/armv7/mx7/psci.S
@@ -0,0 +1,54 @@
+#include <config.h>
+#include <linux/linkage.h>
+
+#include <asm/armv7.h>
+#include <asm/arch-armv7/generictimer.h>
+#include <asm/psci.h>
+
+	.pushsection ._secure.text, "ax"
+
+	.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}
+
+	mov	r0, r1
+	bl	psci_get_cpu_stack_top
+	str	r2, [r0]
+	dsb
+
+	ldr	r2, =psci_cpu_entry
+	bl	imx_cpu_on
+
+	pop	{pc}
+
+.globl psci_cpu_off
+psci_cpu_off:
+
+	bl	psci_cpu_off_common
+	bl	psci_get_cpu_id
+	bl	imx_cpu_off
+
+1: 	wfi
+	b 1b
+
+	.globl psci_text_end
+psci_text_end:
+	.popsection