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Diffstat (limited to 'src/arch/armv7/start.S')
| -rw-r--r-- | src/arch/armv7/start.S | 543 |
1 files changed, 543 insertions, 0 deletions
diff --git a/src/arch/armv7/start.S b/src/arch/armv7/start.S new file mode 100644 index 0000000000..63cac4b98e --- /dev/null +++ b/src/arch/armv7/start.S @@ -0,0 +1,543 @@ +/* + * armboot - Startup Code for OMAP3530/ARM Cortex CPU-core + * + * Copyright (c) 2004 Texas Instruments <r-woodruff2@ti.com> + * + * Copyright (c) 2001 Marius Gröger <mag@sysgo.de> + * Copyright (c) 2002 Alex Züpke <azu@sysgo.de> + * Copyright (c) 2002 Gary Jennejohn <garyj@denx.de> + * Copyright (c) 2003 Richard Woodruff <r-woodruff2@ti.com> + * Copyright (c) 2003 Kshitij <kshitij@ti.com> + * Copyright (c) 2006-2008 Syed Mohammed Khasim <x0khasim@ti.com> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#define __ASSEMBLY__ +#include <system.h> + +.globl _start +_start: b reset + 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 +#ifdef CONFIG_SPL_BUILD +_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 +_pad: .word 0x12345678 /* now 16*4=64 */ +#else +_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 +_pad: .word 0x12345678 /* now 16*4=64 */ +#endif /* CONFIG_SPL_BUILD */ + +.global _end_vect +_end_vect: + + .balignl 16,0xdeadbeef +/************************************************************************* + * + * Startup Code (reset vector) + * + * do important init only if we don't start from memory! + * setup Memory and board specific bits prior to relocation. + * relocate armboot to ram + * setup stack + * + *************************************************************************/ + +.globl _TEXT_BASE +_TEXT_BASE: + .word CONFIG_SYS_TEXT_BASE + +/* + * These are defined in the board-specific linker script. + */ +.globl _bss_start_ofs +_bss_start_ofs: + .word _bss - _start + +.global _image_copy_end_ofs +_image_copy_end_ofs: + .word __image_copy_end - _start + +.globl _bss_end_ofs +_bss_end_ofs: + .word _ebss - _start +# .word __bss_end__ - _start + +.globl _end_ofs +_end_ofs: + .word _end - _start + +#ifdef CONFIG_USE_IRQ +/* IRQ stack memory (calculated at run-time) */ +.globl IRQ_STACK_START +IRQ_STACK_START: + .word 0x0badc0de + +/* IRQ stack memory (calculated at run-time) */ +.globl FIQ_STACK_START +FIQ_STACK_START: + .word 0x0badc0de +#endif + +/* IRQ stack memory (calculated at run-time) + 8 bytes */ +.globl IRQ_STACK_START_IN +IRQ_STACK_START_IN: + .word 0x0badc0de + +/* + * the actual reset code + */ + +reset: +/* bl save_boot_params */ + /* + * set the cpu to SVC32 mode + */ + mrs r0, cpsr + bic r0, r0, #0x1f + orr r0, r0, #0xd3 + msr cpsr,r0 + +#if !defined(CONFIG_TEGRA2) +/* + * Setup vector: + * (OMAP4 spl TEXT_BASE is not 32 byte aligned. + * Continue to use ROM code vector only in OMAP4 spl) + */ +#if !(defined(CONFIG_OMAP44XX) && defined(CONFIG_SPL_BUILD)) + /* Set V=0 in CP15 SCTRL register - for VBAR to point to vector */ + mrc p15, 0, r0, c1, c0, 0 @ Read CP15 SCTRL Register + bic r0, #CR_V @ V = 0 + mcr p15, 0, r0, c1, c0, 0 @ Write CP15 SCTRL Register + + /* Set vector address in CP15 VBAR register */ + ldr r0, =_start + mcr p15, 0, r0, c12, c0, 0 @Set VBAR +#endif +#endif /* !Tegra2 */ + + /* the mask ROM code should have PLL and others stable */ +#ifndef CONFIG_SKIP_LOWLEVEL_INIT + /* + * FIXME(dhendrix): Do we need to explicitly disable icache/dcache + * first? See example 15-3 in Cortex-A programmers guide... + */ + bl cpu_init_cp15 + bl cpu_init_crit +#endif + +/* Set stackpointer in internal RAM to call board_init_f */ +call_board_init_f: + ldr sp, =(CONFIG_SYS_INIT_SP_ADDR) + bic sp, sp, #7 /* 8-byte alignment for ABI compliance */ + ldr r0,=0x00000000 + bl board_init_f + +/*------------------------------------------------------------------------------*/ + +/* + * void relocate_code (addr_sp, gd, addr_moni) + * + * This "function" does not return, instead it continues in RAM + * after relocating the monitor code. + * + */ + .globl relocate_code +relocate_code: + mov r4, r0 /* save addr_sp */ + mov r5, r1 /* save addr of gd */ + mov r6, r2 /* save addr of destination */ + + /* Set up the stack */ +stack_setup: + mov sp, r4 + + adr r0, _start + subs r9, r6, r0 /* r9 <- relocation offset */ + beq clear_bss /* skip relocation */ + mov r1, r6 /* r1 <- scratch for copy_loop */ + ldr r3, _image_copy_end_ofs + add r2, r0, r3 /* r2 <- source end address */ + +copy_loop: + ldmia r0!, {r9-r10} /* copy from source address [r0] */ + stmia r1!, {r9-r10} /* copy to target address [r1] */ + cmp r0, r2 /* until source end address [r2] */ + blo copy_loop + +#ifndef CONFIG_SPL_BUILD + /* + * fix .rel.dyn relocations + */ + ldr r0, _TEXT_BASE /* r0 <- Text base */ + sub r9, r6, r0 /* r9 <- relocation offset */ + ldr r10, _dynsym_start_ofs /* r10 <- sym table ofs */ + add r10, r10, r0 /* r10 <- sym table in FLASH */ + ldr r2, _rel_dyn_start_ofs /* r2 <- rel dyn start ofs */ + add r2, r2, r0 /* r2 <- rel dyn start in FLASH */ + ldr r3, _rel_dyn_end_ofs /* r3 <- rel dyn end ofs */ + add r3, r3, r0 /* r3 <- rel dyn end in FLASH */ +fixloop: + ldr r0, [r2] /* r0 <- location to fix up, IN FLASH! */ + add r0, r0, r9 /* r0 <- location to fix up in RAM */ + ldr r1, [r2, #4] + and r7, r1, #0xff + cmp r7, #23 /* relative fixup? */ + beq fixrel + cmp r7, #2 /* absolute fixup? */ + beq fixabs + /* ignore unknown type of fixup */ + b fixnext +fixabs: + /* absolute fix: set location to (offset) symbol value */ + mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */ + add r1, r10, r1 /* r1 <- address of symbol in table */ + ldr r1, [r1, #4] /* r1 <- symbol value */ + add r1, r1, r9 /* r1 <- relocated sym addr */ + b fixnext +fixrel: + /* relative fix: increase location by offset */ + ldr r1, [r0] + add r1, r1, r9 +fixnext: + str r1, [r0] + add r2, r2, #8 /* each rel.dyn entry is 8 bytes */ + cmp r2, r3 + blo fixloop + b clear_bss +_rel_dyn_start_ofs: + .word __rel_dyn_start - _start +_rel_dyn_end_ofs: + .word __rel_dyn_end - _start +_dynsym_start_ofs: + .word __dynsym_start - _start + +#endif /* #ifndef CONFIG_SPL_BUILD */ + +clear_bss: +#ifdef CONFIG_SPL_BUILD + /* No relocation for SPL */ + ldr r0, =_bss + ldr r1, =_ebss +#else + ldr r0, _bss_start_ofs + ldr r1, _bss_end_ofs + mov r4, r6 /* reloc addr */ + add r0, r0, r4 + add r1, r1, r4 +#endif + mov r2, #0x00000000 /* clear */ + +clbss_l:str r2, [r0] /* clear loop... */ + add r0, r0, #4 + cmp r0, r1 + bne clbss_l + +/* + * We are done. Do not return, instead branch to second part of board + * initialization, now running from RAM. + */ +jump_2_ram: +/* + * If I-cache is enabled invalidate it + */ +#ifndef CONFIG_SYS_ICACHE_OFF + mcr p15, 0, r0, c7, c5, 0 @ invalidate icache + mcr p15, 0, r0, c7, c10, 4 @ DSB + mcr p15, 0, r0, c7, c5, 4 @ ISB +#endif + ldr r0, _board_init_r_ofs + adr r1, _start + add lr, r0, r1 + add lr, lr, r9 + /* setup parameters for board_init_r */ + mov r0, r5 /* gd_t */ + mov r1, r6 /* dest_addr */ + /* jump to it ... */ + mov pc, lr + +_board_init_r_ofs: + .word board_init_r - _start + +/************************************************************************* + * + * cpu_init_cp15 + * + * Setup CP15 registers (cache, MMU, TLBs). The I-cache is turned on unless + * CONFIG_SYS_ICACHE_OFF is defined. + * + *************************************************************************/ +.globl cpu_init_cp15 +cpu_init_cp15: + /* + * Invalidate L1 I/D + */ + mov r0, #0 @ set up for MCR + mcr p15, 0, r0, c8, c7, 0 @ invalidate TLBs + mcr p15, 0, r0, c7, c5, 0 @ invalidate icache + mcr p15, 0, r0, c7, c5, 6 @ invalidate BP array + mcr p15, 0, r0, c7, c10, 4 @ DSB + mcr p15, 0, r0, c7, c5, 4 @ ISB + + /* + * disable MMU stuff and caches + */ + mrc p15, 0, r0, c1, c0, 0 + bic r0, r0, #0x00002000 @ clear bits 13 (--V-) + bic r0, r0, #0x00000007 @ clear bits 2:0 (-CAM) + orr r0, r0, #0x00000002 @ set bit 1 (--A-) Align + orr r0, r0, #0x00000800 @ set bit 11 (Z---) BTB +#ifdef CONFIG_SYS_ICACHE_OFF + bic r0, r0, #0x00001000 @ clear bit 12 (I) I-cache +#else + orr r0, r0, #0x00001000 @ set bit 12 (I) I-cache +#endif + mcr p15, 0, r0, c1, c0, 0 + mov pc, lr @ back to my caller + + +#ifndef CONFIG_SKIP_LOWLEVEL_INIT +/************************************************************************* + * + * CPU_init_critical registers + * + * setup important registers + * setup memory timing + * + *************************************************************************/ +cpu_init_crit: + /* + * Jump to board specific initialization... + * The Mask ROM will have already initialized + * basic memory. Go here to bump up clock rate and handle + * wake up conditions. + */ + mov ip, lr @ persevere link reg across call + bl lowlevel_init @ go setup pll,mux,memory + mov lr, ip @ restore link + mov pc, lr @ back to my caller +#endif + +#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 + sub sp, sp, #S_FRAME_SIZE @ carve out a frame on current + @ user stack + stmia sp, {r0 - r12} @ Save user registers (now in + @ svc mode) r0-r12 + ldr r2, IRQ_STACK_START_IN @ set base 2 words into abort + @ stack + ldmia r2, {r2 - r3} @ get values for "aborted" pc + @ and cpsr (into parm regs) + 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 + add r8, sp, #S_PC @ !! R8 NEEDS to be saved !! + @ a reserved stack spot would + @ be good. + 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 (enter + @ in banked mode) + + 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_bad_stack_swi + sub r13, r13, #4 @ space on current stack for + @ scratch reg. + str r0, [r13] @ save R0's value. + ldr r0, IRQ_STACK_START_IN @ get data regions start + @ spots for abort stack + str lr, [r0] @ save caller lr in position 0 + @ of saved stack + mrs r0, spsr @ get the spsr + str lr, [r0, #4] @ save spsr in position 1 of + @ saved stack + ldr r0, [r13] @ restore r0 + add r13, r13, #4 @ pop stack entry + .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 + +/* + * exception handlers + */ + .align 5 +undefined_instruction: + get_bad_stack + bad_save_user_regs + bl do_undefined_instruction + + .align 5 +software_interrupt: + get_bad_stack_swi + 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 effective 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 /* CONFIG_USE_IRQ */ +#endif /* CONFIG_SPL_BUILD */ |