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/*
 * ARM Kernel entry point
 *
 * Copyright (C) 2007 Bahadir Balban
 */

#include INC_ARCH(asm.h)

#define C15_C0_M                0x0001  /* MMU */
#define C15_C0_A                0x0002  /* Alignment */
#define C15_C0_C                0x0004  /* (D) Cache */
#define C15_C0_W                0x0008  /* Write buffer */
#define C15_C0_B                0x0080  /* Endianness */
#define C15_C0_S                0x0100  /* System */
#define C15_C0_R                0x0200  /* ROM */
#define C15_C0_Z                0x0800  /* Branch Prediction */
#define C15_C0_I                0x1000  /* I cache */
#define C15_C0_V                0x2000  /* High vectors */


/*
 * This is the entry point of the L4 ARM architecture.
 * The boot loader must call _start with the processor in privileged
 * mode and mmu disabled.
 */
        .section .text.head
BEGIN_PROC(_start)
        /* Setup status register for supervisor mode, interrupts disabled */
        msr     cpsr_fcxs, #ARM_MODE_SVC

        /* Disable mmu if it is enabled */
        mrc     p15, 0, r0, c1, c0, 0
        bic     r0, r0, #C15_C0_M       @ Disable MMU
        bic     r0, r0, #C15_C0_C       @ Disable (D) Cache
        bic     r0, r0, #C15_C0_I       @ Disable I cache
        bic     r0, r0, #C15_C0_W       @ Disable Write buffer
        bic     r0, r0, #C15_C0_Z       @ Disable Branch prediction
        mcr     p15, 0, r0, c1, c0, 0

        /* Setup boot stack (physical address) */
        ldr     sp,     _kernel_init_stack

        /* Exception stacks are defined in vector page */
        msr     cpsr_fc, #ARM_NOIRQ_ABT
        ldr     sp,     _kernel_abt_stack
        msr     cpsr_fc, #ARM_NOIRQ_IRQ
        ldr     sp,     _kernel_irq_stack
        msr     cpsr_fc, #ARM_NOIRQ_FIQ
        ldr     sp,     _kernel_fiq_stack
        msr     cpsr_fc, #ARM_NOIRQ_UND
        ldr     sp,     _kernel_und_stack
        msr     cpsr_fc, #ARM_NOIRQ_SVC

        /* Jump to start_kernel */
        bl      start_kernel

        /* Never reached */
1:
        b       1b

_kernel_init_stack:
        .word   _bootstack_physical

/* Exception stacks are defined in vector page */
_kernel_abt_stack:
        .word   __abt_stack_high
_kernel_irq_stack:
        .word   __irq_stack_high
_kernel_fiq_stack:
        .word   __fiq_stack_high
_kernel_und_stack:
        .word   __und_stack_high