diff options
Diffstat (limited to 'board/denx')
| -rw-r--r-- | board/denx/m28evk/start.S | 264 |
1 files changed, 51 insertions, 213 deletions
diff --git a/board/denx/m28evk/start.S b/board/denx/m28evk/start.S index cf675995d..94696d6cd 100644 --- a/board/denx/m28evk/start.S +++ b/board/denx/m28evk/start.S @@ -58,54 +58,58 @@ .globl _start _start: b reset -#ifdef CONFIG_SPL_BUILD -/* No exception handlers in preloader */ - ldr pc, _hang - ldr pc, _hang - ldr pc, _hang - ldr pc, _hang - b reset - ldr pc, _hang - ldr pc, _hang + b undefined_instruction + b software_interrupt + b prefetch_abort + b data_abort + b not_used + b irq + b fiq -_hang: - .word do_hang -/* pad to 64 byte boundary */ - .word 0x12345678 - .word 0x12345678 - .word 0x12345678 - .word 0x12345678 - .word 0x12345678 - .word 0x12345678 - .word 0x12345678 -#else - ldr pc, _undefined_instruction - ldr pc, _software_interrupt - ldr pc, _prefetch_abort - ldr pc, _data_abort - ldr pc, _not_used - ldr pc, _irq - ldr pc, _fiq +/* + * Vector table, located at address 0x20. + * This table allows the code running AFTER SPL, the U-Boot, to install it's + * interrupt handlers here. The problem is that the U-Boot is loaded into RAM, + * including it's interrupt vectoring table and the table at 0x0 is still the + * SPLs. So if interrupt happens in U-Boot, the SPLs interrupt vectoring table + * is still used. + */ +_vt_reset: + .word _reset +_vt_undefined_instruction: + .word _hang +_vt_software_interrupt: + .word _hang +_vt_prefetch_abort: + .word _hang +_vt_data_abort: + .word _hang +_vt_not_used: + .word _reset +_vt_irq: + .word _hang +_vt_fiq: + .word _hang -_undefined_instruction: - .word undefined_instruction -_software_interrupt: - .word software_interrupt -_prefetch_abort: - .word prefetch_abort -_data_abort: - .word data_abort -_not_used: - .word not_used -_irq: - .word irq -_fiq: - .word fiq +reset: + ldr pc, _vt_reset +undefined_instruction: + ldr pc, _vt_undefined_instruction +software_interrupt: + ldr pc, _vt_software_interrupt +prefetch_abort: + ldr pc, _vt_prefetch_abort +data_abort: + ldr pc, _vt_data_abort +not_used: + ldr pc, _vt_not_used +irq: + ldr pc, _vt_irq +fiq: + ldr pc, _vt_fiq -#endif /* CONFIG_SPL_BUILD */ .balignl 16,0xdeadbeef - /* ************************************************************************* * @@ -162,7 +166,7 @@ IRQ_STACK_START_IN: * the actual reset code */ -reset: +_reset: /* * Store all registers on old stack pointer, this will allow us later to * return to the BootROM and let the BootROM load U-Boot into RAM. @@ -220,177 +224,11 @@ cpu_init_crit: mcr p15, 0, r0, c1, c0, 0 mov pc, lr /* back to my caller */ -#endif /* CONFIG_SKIP_LOWLEVEL_INIT */ - -#ifndef CONFIG_SPL_BUILD -/* - ************************************************************************* - * - * Interrupt handling - * - ************************************************************************* - */ - -@ -@ IRQ stack frame. -@ -#define S_FRAME_SIZE 72 - -#define S_OLD_R0 68 -#define S_PSR 64 -#define S_PC 60 -#define S_LR 56 -#define S_SP 52 - -#define S_IP 48 -#define S_FP 44 -#define S_R10 40 -#define S_R9 36 -#define S_R8 32 -#define S_R7 28 -#define S_R6 24 -#define S_R5 20 -#define S_R4 16 -#define S_R3 12 -#define S_R2 8 -#define S_R1 4 -#define S_R0 0 - -#define MODE_SVC 0x13 -#define I_BIT 0x80 - -/* - * use bad_save_user_regs for abort/prefetch/undef/swi ... - * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling - */ - - .macro bad_save_user_regs - @ carve out a frame on current user stack - sub sp, sp, #S_FRAME_SIZE - stmia sp, {r0 - r12} @ Save user registers (now in svc mode) r0-r12 - ldr r2, IRQ_STACK_START_IN - @ get values for "aborted" pc and cpsr (into parm regs) - ldmia r2, {r2 - r3} - add r0, sp, #S_FRAME_SIZE @ grab pointer to old stack - add r5, sp, #S_SP - mov r1, lr - stmia r5, {r0 - r3} @ save sp_SVC, lr_SVC, pc, cpsr - mov r0, sp @ save current stack into r0 (param register) - .endm - - .macro irq_save_user_regs - sub sp, sp, #S_FRAME_SIZE - stmia sp, {r0 - r12} @ Calling r0-r12 - @ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good. - add r8, sp, #S_PC - stmdb r8, {sp, lr}^ @ Calling SP, LR - str lr, [r8, #0] @ Save calling PC - mrs r6, spsr - str r6, [r8, #4] @ Save CPSR - str r0, [r8, #8] @ Save OLD_R0 - mov r0, sp - .endm - - .macro irq_restore_user_regs - ldmia sp, {r0 - lr}^ @ Calling r0 - lr - mov r0, r0 - ldr lr, [sp, #S_PC] @ Get PC - add sp, sp, #S_FRAME_SIZE - subs pc, lr, #4 @ return & move spsr_svc into cpsr - .endm - - .macro get_bad_stack - ldr r13, IRQ_STACK_START_IN @ setup our mode stack - - str lr, [r13] @ save caller lr in position 0 of saved stack - mrs lr, spsr @ get the spsr - str lr, [r13, #4] @ save spsr in position 1 of saved stack - mov r13, #MODE_SVC @ prepare SVC-Mode - @ msr spsr_c, r13 - msr spsr, r13 @ switch modes, make sure moves will execute - mov lr, pc @ capture return pc - movs pc, lr @ jump to next instruction & switch modes. - .endm - - .macro get_irq_stack @ setup IRQ stack - ldr sp, IRQ_STACK_START - .endm - - .macro get_fiq_stack @ setup FIQ stack - ldr sp, FIQ_STACK_START - .endm -#endif /* CONFIG_SPL_BUILD */ -/* - * exception handlers - */ -#ifdef CONFIG_SPL_BUILD .align 5 -do_hang: +#endif /* CONFIG_SKIP_LOWLEVEL_INIT */ + +_hang: ldr sp, _TEXT_BASE /* switch to abort stack */ 1: bl 1b /* hang and never return */ -#else /* !CONFIG_SPL_BUILD */ - .align 5 -undefined_instruction: - get_bad_stack - bad_save_user_regs - bl do_undefined_instruction - - .align 5 -software_interrupt: - get_bad_stack - bad_save_user_regs - bl do_software_interrupt - - .align 5 -prefetch_abort: - get_bad_stack - bad_save_user_regs - bl do_prefetch_abort - - .align 5 -data_abort: - get_bad_stack - bad_save_user_regs - bl do_data_abort - - .align 5 -not_used: - get_bad_stack - bad_save_user_regs - bl do_not_used - -#ifdef CONFIG_USE_IRQ - - .align 5 -irq: - get_irq_stack - irq_save_user_regs - bl do_irq - irq_restore_user_regs - - .align 5 -fiq: - get_fiq_stack - /* someone ought to write a more effiction fiq_save_user_regs */ - irq_save_user_regs - bl do_fiq - irq_restore_user_regs - -#else - - .align 5 -irq: - get_bad_stack - bad_save_user_regs - bl do_irq - - .align 5 -fiq: - get_bad_stack - bad_save_user_regs - bl do_fiq - -#endif -#endif /* CONFIG_SPL_BUILD */ |