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Diffstat (limited to 'arch/avr32/cpu/start.S')
| -rw-r--r-- | arch/avr32/cpu/start.S | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/arch/avr32/cpu/start.S b/arch/avr32/cpu/start.S new file mode 100644 index 0000000..d37a46e --- /dev/null +++ b/arch/avr32/cpu/start.S @@ -0,0 +1,275 @@ +/* + * Copyright (C) 2005-2008 Atmel Corporation + * + * 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 + */ +#include <config.h> +#include <asm/ptrace.h> +#include <asm/sysreg.h> + +#define SYSREG_MMUCR_I_OFFSET 2 +#define SYSREG_MMUCR_S_OFFSET 4 + +#define SR_INIT (SYSREG_BIT(GM) | SYSREG_BIT(EM) | SYSREG_BIT(M0)) +#define CPUCR_INIT (SYSREG_BIT(BI) | SYSREG_BIT(BE) \ + | SYSREG_BIT(FE) | SYSREG_BIT(RE) \ + | SYSREG_BIT(IBE) | SYSREG_BIT(IEE)) + + /* + * To save some space, we use the same entry point for + * exceptions and reset. This avoids lots of alignment padding + * since the reset vector is always suitably aligned. + */ + .section .exception.text, "ax", @progbits + .global _start + .global _evba + .type _start, @function + .type _evba, @function +_start: + .size _start, 0 +_evba: + .org 0x00 + rjmp unknown_exception /* Unrecoverable exception */ + .org 0x04 + rjmp unknown_exception /* TLB multiple hit */ + .org 0x08 + rjmp unknown_exception /* Bus error data fetch */ + .org 0x0c + rjmp unknown_exception /* Bus error instruction fetch */ + .org 0x10 + rjmp unknown_exception /* NMI */ + .org 0x14 + rjmp unknown_exception /* Instruction address */ + .org 0x18 + rjmp unknown_exception /* ITLB protection */ + .org 0x1c + rjmp unknown_exception /* Breakpoint */ + .org 0x20 + rjmp unknown_exception /* Illegal opcode */ + .org 0x24 + rjmp unknown_exception /* Unimplemented instruction */ + .org 0x28 + rjmp unknown_exception /* Privilege violation */ + .org 0x2c + rjmp unknown_exception /* Floating-point */ + .org 0x30 + rjmp unknown_exception /* Coprocessor absent */ + .org 0x34 + rjmp unknown_exception /* Data Address (read) */ + .org 0x38 + rjmp unknown_exception /* Data Address (write) */ + .org 0x3c + rjmp unknown_exception /* DTLB Protection (read) */ + .org 0x40 + rjmp unknown_exception /* DTLB Protection (write) */ + .org 0x44 + rjmp unknown_exception /* DTLB Modified */ + + .org 0x50 + rjmp unknown_exception /* ITLB Miss */ + .org 0x60 + rjmp unknown_exception /* DTLB Miss (read) */ + .org 0x70 + rjmp unknown_exception /* DTLB Miss (write) */ + + .size _evba, . - _evba + + .align 2 + .type unknown_exception, @function +unknown_exception: + /* Figure out whether we're handling an exception (Exception + * mode) or just booting (Supervisor mode). */ + csrfcz SYSREG_M1_OFFSET + brcc at32ap_cpu_bootstrap + + /* This is an exception. Complain. */ + pushm r0-r12 + sub r8, sp, REG_R12 - REG_R0 - 4 + mov r9, lr + mfsr r10, SYSREG_RAR_EX + mfsr r11, SYSREG_RSR_EX + pushm r8-r11 + mfsr r12, SYSREG_ECR + mov r11, sp + rcall do_unknown_exception +1: rjmp 1b + + /* The COUNT/COMPARE timer interrupt handler */ + .global timer_interrupt_handler + .type timer_interrupt_handler,@function + .align 2 +timer_interrupt_handler: + /* + * Increment timer_overflow and re-write COMPARE with 0xffffffff. + * + * We're running at interrupt level 3, so we don't need to save + * r8-r12 or lr to the stack. + */ + lda.w r8, timer_overflow + ld.w r9, r8[0] + mov r10, -1 + mtsr SYSREG_COMPARE, r10 + sub r9, -1 + st.w r8[0], r9 + rete + + /* + * CPU bootstrap after reset is handled here. SoC code may + * override this in case they need to initialize oscillators, + * etc. + */ + .section .text.at32ap_cpu_bootstrap, "ax", @progbits + .global at32ap_cpu_bootstrap + .weak at32ap_cpu_bootstrap + .type at32ap_cpu_bootstrap, @function + .align 2 +at32ap_cpu_bootstrap: + /* Reset the Status Register */ + mov r0, lo(SR_INIT) + orh r0, hi(SR_INIT) + mtsr SYSREG_SR, r0 + + /* Reset CPUCR and invalidate the BTB */ + mov r2, CPUCR_INIT + mtsr SYSREG_CPUCR, r2 + + /* Flush the caches */ + mov r1, 0 + cache r1[4], 8 + cache r1[0], 0 + sync 0 + + /* Reset the MMU to default settings */ + mov r0, SYSREG_BIT(MMUCR_S) | SYSREG_BIT(MMUCR_I) + mtsr SYSREG_MMUCR, r0 + + /* Internal RAM should not need any initialization. We might + have to initialize external RAM here if the part doesn't + have internal RAM (or we may use the data cache) */ + + /* Jump to cacheable segment */ + lddpc pc, 1f + + .align 2 +1: .long at32ap_low_level_init + .size _start, . - _start + + /* Common CPU bootstrap code after oscillator/cache/etc. init */ + .section .text.avr32ap_low_level_init, "ax", @progbits + .global at32ap_low_level_init + .type at32ap_low_level_init, @function + .align 2 +at32ap_low_level_init: + lddpc sp, sp_init + + /* Initialize the GOT pointer */ + lddpc r6, got_init +3: rsub r6, pc + + /* Let's go */ + rjmp board_init_f + + .align 2 + .type sp_init,@object +sp_init: + .long CONFIG_SYS_INIT_SP_ADDR +got_init: + .long 3b - _GLOBAL_OFFSET_TABLE_ + + /* + * void relocate_code(new_sp, new_gd, monitor_addr) + * + * Relocate the u-boot image into RAM and continue from there. + * Does not return. + */ + .section .text.relocate_code,"ax",@progbits + .global relocate_code + .type relocate_code,@function +relocate_code: + mov sp, r12 /* use new stack */ + mov r12, r11 /* save new_gd */ + mov r11, r10 /* save destination address */ + + /* copy .text section and flush the cache along the way */ + lda.w r8, _text + lda.w r9, _etext + sub lr, r10, r8 /* relocation offset */ + +1: ldm r8++, r0-r3 + stm r10, r0-r3 + sub r10, -16 + ldm r8++, r0-r3 + stm r10, r0-r3 + sub r10, -16 + cp.w r8, r9 + cache r10[-4], 0x0d /* dcache clean/invalidate */ + cache r10[-4], 0x01 /* icache invalidate */ + brlt 1b + + /* flush write buffer */ + sync 0 + + /* copy data sections */ + lda.w r9, _edata +1: ld.d r0, r8++ + st.d r10++, r0 + cp.w r8, r9 + brlt 1b + + /* zero out .bss */ + mov r0, 0 + mov r1, 0 + lda.w r9, _end + sub r9, r8 +1: st.d r10++, r0 + sub r9, 8 + brgt 1b + + /* jump to RAM */ + sub r0, pc, . - in_ram + add pc, r0, lr + + .align 2 +in_ram: + /* find the new GOT and relocate it */ + lddpc r6, got_init_reloc +3: rsub r6, pc + mov r8, r6 + lda.w r9, _egot + lda.w r10, _got + sub r9, r10 +1: ld.w r0, r8[0] + add r0, lr + st.w r8++, r0 + sub r9, 4 + brgt 1b + + /* Move the exception handlers */ + mfsr r2, SYSREG_EVBA + add r2, lr + mtsr SYSREG_EVBA, r2 + + /* Do the rest of the initialization sequence */ + call board_init_r + + .align 2 +got_init_reloc: + .long 3b - _GLOBAL_OFFSET_TABLE_ + + .size relocate_code, . - relocate_code |