/**
* @file
*
* @brief Boot and system start code.
*/
/*
* Copyright (c) 2008-2014 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Obere Lagerstr. 30
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#include <rtems/asm.h>
#include <rtems/system.h>
#include <rtems/score/cpu.h>
#include <bspopts.h>
#include <bsp/irq.h>
#include <bsp/linker-symbols.h>
/* External symbols */
.extern bsp_reset
.extern boot_card
.extern bsp_start_hook_0
.extern bsp_start_hook_1
.extern bsp_stack_irq_end
.extern bsp_stack_fiq_end
.extern bsp_stack_abt_end
.extern bsp_stack_und_end
.extern bsp_stack_svc_end
#ifdef RTEMS_SMP
.extern bsp_stack_all_size
#endif
.extern _ARMV4_Exception_undef_default
.extern _ARMV4_Exception_swi_default
.extern _ARMV4_Exception_data_abort_default
.extern _ARMV4_Exception_pref_abort_default
.extern _ARMV4_Exception_reserved_default
.extern _ARMV4_Exception_interrupt
.extern _ARMV4_Exception_fiq_default
.extern _ARMV7M_Exception_default
#ifdef BSP_START_NEEDS_REGISTER_INITIALIZATION
.extern bsp_start_init_registers_core
.extern bsp_start_init_registers_banked_fiq
.extern bsp_start_init_registers_vfp
#endif
#ifdef BSP_START_IN_HYP_SUPPORT
.extern bsp_start_arm_drop_hyp_mode
.globl bsp_start_hyp_vector_table_begin
#endif
/* Global symbols */
.globl _start
.globl bsp_start_vector_table_begin
.globl bsp_start_vector_table_end
.globl bsp_start_vector_table_size
.globl bsp_vector_table_size
.globl bsp_start_hook_0_done
.section ".bsp_start_text", "ax"
#if defined(ARM_MULTILIB_ARCH_V4)
.arm
/*
* This is the exception vector table and the pointers to the default
* exceptions handlers.
*/
bsp_start_vector_table_begin:
ldr pc, handler_addr_reset
ldr pc, handler_addr_undef
ldr pc, handler_addr_swi
ldr pc, handler_addr_prefetch
ldr pc, handler_addr_abort
/* Program signature checked by boot loader */
.word 0xb8a06f58
ldr pc, handler_addr_irq
ldr pc, handler_addr_fiq
handler_addr_reset:
#ifdef BSP_START_RESET_VECTOR
.word BSP_START_RESET_VECTOR
#else
.word _start
#endif
handler_addr_undef:
.word _ARMV4_Exception_undef_default
handler_addr_swi:
.word _ARMV4_Exception_swi_default
handler_addr_prefetch:
.word _ARMV4_Exception_pref_abort_default
handler_addr_abort:
.word _ARMV4_Exception_data_abort_default
handler_addr_reserved:
.word _ARMV4_Exception_reserved_default
handler_addr_irq:
.word _ARMV4_Exception_interrupt
handler_addr_fiq:
.word _ARMV4_Exception_fiq_default
bsp_start_vector_table_end:
#ifdef BSP_START_IN_HYP_SUPPORT
bsp_start_hyp_vector_table_begin:
ldr pc, handler_addr_hyp_reset
ldr pc, handler_addr_hyp_undef
ldr pc, handler_addr_hyp_swi
ldr pc, handler_addr_hyp_prefetch
ldr pc, handler_addr_hyp_abort
ldr pc, handler_addr_hyp_hyp
ldr pc, handler_addr_hyp_irq
ldr pc, handler_addr_hyp_fiq
handler_addr_hyp_reset:
.word _ARMV4_Exception_reserved_default
handler_addr_hyp_undef:
.word _ARMV4_Exception_reserved_default
handler_addr_hyp_swi:
.word _ARMV4_Exception_reserved_default
handler_addr_hyp_prefetch:
.word _ARMV4_Exception_reserved_default
handler_addr_hyp_abort:
.word _ARMV4_Exception_reserved_default
handler_addr_hyp_hyp:
.word _ARMV4_Exception_reserved_default
handler_addr_hyp_irq:
.word _ARMV4_Exception_reserved_default
handler_addr_hyp_fiq:
.word _ARMV4_Exception_reserved_default
bsp_start_hyp_vector_table_end:
#endif
/* Start entry */
_start:
/*
* We do not save the context since we do not return to the boot
* loader but preserve r1 and r2 to allow access to bootloader parameters
*/
#ifndef BSP_START_NEEDS_REGISTER_INITIALIZATION
mov r5, r1 /* machine type number or ~0 for DT boot */
mov r6, r2 /* physical address of ATAGs or DTB */
#else /* BSP_START_NEEDS_REGISTER_INITIALIZATION */
bl bsp_start_init_registers_core
#endif
#ifdef RTEMS_SMP
/* Read MPIDR */
mrc p15, 0, r0, c0, c0, 5
/* Calculate stack offset */
and r0, #0xff
ldr r1, =bsp_stack_all_size
mul r1, r0
#endif
mrs r4, cpsr /* save original procesor status value */
#ifdef BSP_START_IN_HYP_SUPPORT
orr r0, r4, #(ARM_PSR_I | ARM_PSR_F)
msr cpsr, r4
and r0, r4, #ARM_PSR_M_MASK
cmp r0, #ARM_PSR_M_HYP
bne bsp_start_skip_hyp_svc_switch
/* Boot loader stats kernel in HYP mode, switch to SVC necessary */
ldr sp, =bsp_stack_hyp_end
#ifdef RTEMS_SMP
add sp, r1
#endif
bl bsp_start_arm_drop_hyp_mode
bsp_start_skip_hyp_svc_switch:
#endif
/*
* Set SVC mode, disable interrupts and enable ARM instructions.
*/
mov r0, #(ARM_PSR_M_SVC | ARM_PSR_I | ARM_PSR_F)
msr cpsr, r0
/* Initialize stack pointer registers for the various modes */
/* Enter IRQ mode and set up the IRQ stack pointer */
mov r0, #(ARM_PSR_M_IRQ | ARM_PSR_I | ARM_PSR_F)
msr cpsr, r0
ldr sp, =bsp_stack_irq_end
#ifdef RTEMS_SMP
add sp, r1
#endif
/* Enter FIQ mode and set up the FIQ stack pointer */
mov r0, #(ARM_PSR_M_FIQ | ARM_PSR_I | ARM_PSR_F)
msr cpsr, r0
ldr sp, =bsp_stack_fiq_end
#ifdef RTEMS_SMP
add sp, r1
#endif
#ifdef BSP_START_NEEDS_REGISTER_INITIALIZATION
bl bsp_start_init_registers_banked_fiq
#endif
/* Enter ABT mode and set up the ABT stack pointer */
mov r0, #(ARM_PSR_M_ABT | ARM_PSR_I | ARM_PSR_F)
msr cpsr, r0
ldr sp, =bsp_stack_abt_end
#ifdef RTEMS_SMP
add sp, r1
#endif
/* Enter UND mode and set up the UND stack pointer */
mov r0, #(ARM_PSR_M_UND | ARM_PSR_I | ARM_PSR_F)
msr cpsr, r0
ldr sp, =bsp_stack_und_end
#ifdef RTEMS_SMP
add sp, r1
#endif
/* Enter SVC mode and set up the SVC stack pointer */
mov r0, #(ARM_PSR_M_SVC | ARM_PSR_I | ARM_PSR_F)
msr cpsr, r0
ldr sp, =bsp_stack_svc_end
#ifdef RTEMS_SMP
add sp, r1
#endif
/* Stay in SVC mode */
#ifdef ARM_MULTILIB_VFP
/* Read CPACR */
mrc p15, 0, r0, c1, c0, 2
/* Enable CP10 and CP11 */
orr r0, r0, #(1 << 20)
orr r0, r0, #(1 << 22)
/*
* Clear ASEDIS and D32DIS. Writes to D32DIS are ignored for VFP-D16.
*/
bic r0, r0, #(3 << 30)
/* Write CPACR */
mcr p15, 0, r0, c1, c0, 2
isb
/* Enable FPU */
mov r0, #(1 << 30)
vmsr FPEXC, r0
#ifdef BSP_START_NEEDS_REGISTER_INITIALIZATION
bl bsp_start_init_registers_vfp
#endif
#endif /* ARM_MULTILIB_VFP */
/*
* Branch to start hook 0.
*
* The previous code and parts of the start hook 0 may run with an
* address offset. This implies that only branches relative to the
* program counter are allowed. After the start hook 0 it is assumed
* that the code can run at its intended position. Thus the link
* register will be loaded with the absolute address. In THUMB mode
* the start hook 0 must be within a 2kByte range due to the branch
* instruction limitation.
*/
ldr lr, =bsp_start_hook_0_done
#ifdef __thumb__
orr lr, #1
#endif
SWITCH_FROM_ARM_TO_THUMB r0
mov r0, r4 /* original cpsr value */
mov r1, r5 /* machine type number or ~0 for DT boot */
mov r2, r6 /* physical address of ATAGs or DTB */
b bsp_start_hook_0
bsp_start_hook_0_done:
SWITCH_FROM_THUMB_TO_ARM
/*
* Initialize the exception vectors. This includes the exceptions
* vectors and the pointers to the default exception handlers.
*/
stmdb sp!, {r4, r5, r6}
ldr r0, =bsp_vector_table_begin
adr r1, bsp_start_vector_table_begin
cmp r0, r1
beq bsp_vector_table_copy_done
ldmia r1!, {r2-r9}
stmia r0!, {r2-r9}
ldmia r1!, {r2-r9}
stmia r0!, {r2-r9}
bsp_vector_table_copy_done:
ldmia sp!, {r0, r1, r2}
SWITCH_FROM_ARM_TO_THUMB r3
/* Branch to start hook 1 */
bl bsp_start_hook_1
/* Branch to boot card */
mov r0, #0
bl boot_card
twiddle:
/* Branch to reset function */
bl bsp_reset
b twiddle
#elif defined(ARM_MULTILIB_ARCH_V7M)
#include <rtems/score/armv7m.h>
.syntax unified
.extern bsp_stack_main_end
.thumb
bsp_start_vector_table_begin:
.word bsp_stack_main_end
.word _start /* Reset */
.word _ARMV7M_Exception_default /* NMI */
.word _ARMV7M_Exception_default /* Hard Fault */
.word _ARMV7M_Exception_default /* MPU Fault */
.word _ARMV7M_Exception_default /* Bus Fault */
.word _ARMV7M_Exception_default /* Usage Fault */
.word _ARMV7M_Exception_default /* Reserved */
.word _ARMV7M_Exception_default /* Reserved */
.word _ARMV7M_Exception_default /* Reserved */
.word _ARMV7M_Exception_default /* Reserved */
.word _ARMV7M_Exception_default /* SVC */
.word _ARMV7M_Exception_default /* Debug Monitor */
.word _ARMV7M_Exception_default /* Reserved */
.word _ARMV7M_Exception_default /* PendSV */
.word _ARMV7M_Exception_default /* SysTick */
.rept BSP_INTERRUPT_VECTOR_MAX + 1
.word _ARMV7M_Exception_default /* IRQ */
.endr
bsp_start_vector_table_end:
.thumb_func
_start:
#ifdef BSP_START_NEEDS_REGISTER_INITIALIZATION
bl bsp_start_init_registers_core
#endif
#ifdef ARM_MULTILIB_VFP
/*
* Enable CP10 and CP11 coprocessors for privileged and user mode in
* CPACR (bits 20-23). Ensure that write to register completes.
*/
ldr r0, =ARMV7M_CPACR
ldr r1, [r0]
orr r1, r1, #(0xf << 20)
str r1, [r0]
dsb
isb
#ifdef BSP_START_NEEDS_REGISTER_INITIALIZATION
bl bsp_start_init_registers_vfp
#endif
#endif /* ARM_MULTILIB_VFP */
ldr sp, =bsp_stack_main_end
ldr lr, =bsp_start_hook_0_done + 1
b bsp_start_hook_0
bsp_start_hook_0_done:
bl bsp_start_hook_1
movs r0, #0
bl boot_card
twiddle:
bl bsp_reset
b twiddle
#endif /* defined(ARM_MULTILIB_ARCH_V7M) */
.set bsp_start_vector_table_size, bsp_start_vector_table_end - bsp_start_vector_table_begin
.set bsp_vector_table_size, bsp_start_vector_table_size
