/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * $Id$ * * Copyright (C) 2008 by Maurus Cuelenaere * * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/ /* * init.S * * Initialization code for JzRISC. * * Author: Seeger Chin * e-mail: seeger.chin@gmail.com * * Copyright (C) 2006 Ingenic Semiconductor Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * */ #include "config.h" #include "mips.h" .text .set mips3 .extern system_main .global _start .section .init.text .set noreorder .set noat #ifdef BOOTLOADER .word 0 /* HACK */ .word 0 /* HACK */ #endif _start: la ra, _start //---------------------------------------------------- // init cp0 registers. //---------------------------------------------------- mtc0 zero, C0_WATCHLO mtc0 zero, C0_WATCHHI li t0, (M_StatusBEV | M_StatusIM7 | M_StatusIM6 \ | M_StatusIM5 | M_StatusIM4 | M_StatusIM3 \ | M_StatusIM2 | M_StatusERL) // BEV = Enable Boot Exception Vectors // IMx = Interrupt mask // ERL = Denotes error level mtc0 t0, C0_STATUS li t1, M_CauseIV mtc0 t1, C0_CAUSE //---------------------------------------------------- // init caches, assumes a 4way*128set*32byte i/d cache //---------------------------------------------------- li t0, 3 // enable cache for kseg0 accesses mtc0 t0, C0_CONFIG // CONFIG reg la t0, 0x80000000 // an idx op should use a unmappable address ori t1, t0, 0x4000 // 16kB cache mtc0 zero, C0_TAGLO // TAGLO reg mtc0 zero, C0_TAGHI // TAGHI reg _init_cache_loop: cache 0x8, 0(t0) // index store icache tag cache 0x9, 0(t0) // index store dcache tag bne t0, t1, _init_cache_loop addiu t0, t0, 0x20 // 32 bytes per cache line nop //---------------------------------------------------- // Invalidate BTB //---------------------------------------------------- mfc0 t0, C0_CONFIG nop ori t0, 2 mtc0 t0, C0_CONFIG nop //---------------------------------------------------- // clear BSS section //---------------------------------------------------- la t0, _edata la t1, _end _init_bss_loop: sw zero, 0(t0) bne t0, t1, _init_bss_loop addiu t0, 4 //---------------------------------------------------- // setup stack, jump to C code //---------------------------------------------------- la sp, stackend la t0, stackbegin li t1, 0xDEADBEEF _init_stack_loop: sw t1, 0(t0) bne t0, sp, _init_stack_loop addiu t0, t0, 4 la t0, system_main jr t0 nop .section .vectors, "ax", %progbits .extern real_exception_handler .global except_common_entry .type except_common_entry,@function except_common_entry: la k0, real_exception_handler jr k0 nop nop nop .extern _int .extern _exception .global real_exception_handler .type real_exception_handler,@function .set noreorder real_exception_handler: addiu sp, -0x80 sw ra, 0(sp) sw fp, 4(sp) sw gp, 8(sp) sw t9, 0xC(sp) sw t8, 0x10(sp) sw s7, 0x14(sp) sw s6, 0x18(sp) sw s5, 0x1C(sp) sw s4, 0x20(sp) sw s3, 0x24(sp) sw s2, 0x28(sp) sw s1, 0x2C(sp) sw s0, 0x30(sp) sw t7, 0x34(sp) sw t6, 0x38(sp) sw t5, 0x3C(sp) sw t4, 0x40(sp) sw t3, 0x44(sp) sw t2, 0x48(sp) sw t1, 0x4C(sp) sw t0, 0x50(sp) sw a3, 0x54(sp) sw a2, 0x58(sp) sw a1, 0x5C(sp) sw a0, 0x60(sp) sw v1, 0x64(sp) sw v0, 0x68(sp) sw $1, 0x6C(sp) mflo t0 # Move From LO nop sw t0, 0x70(sp) mfhi t0 # Move From HI nop sw t0, 0x74(sp) mfc0 t0, C0_STATUS # Status register sll zero, 1 sll zero, 1 sll zero, 1 sll zero, 1 sw t0, 0x78(sp) mfc0 t0, C0_EPC # Exception Program Counter sll zero, 1 sll zero, 1 sll zero, 1 sll zero, 1 sw t0, 0x7C(sp) li k1, 0x7C mfc0 k0, C0_CAUSE # C0_CAUSE of last exception and k0, k1 beq zero, k0, _int nop la k0, _exception jr k0 nop .global _int .type _int,@function _int: jal intr_handler nop lw ra, 0(sp) lw fp, 4(sp) sw gp, 8(sp) lw t9, 0xC(sp) lw t8, 0x10(sp) lw s7, 0x14(sp) lw s6, 0x18(sp) lw s5, 0x1C(sp) lw s4, 0x20(sp) lw s3, 0x24(sp) lw s2, 0x28(sp) lw s1, 0x2C(sp) lw s0, 0x30(sp) lw t7, 0x34(sp) lw t6, 0x38(sp) lw t5, 0x3C(sp) lw t4, 0x40(sp) lw t3, 0x44(sp) lw t2, 0x48(sp) lw t1, 0x4C(sp) lw t0, 0x50(sp) lw a3, 0x54(sp) lw a2, 0x58(sp) lw a1, 0x5C(sp) lw a0, 0x60(sp) lw v1, 0x64(sp) lw v0, 0x68(sp) lw v1, 0x6C(sp) lw k0, 0x70(sp) mtlo k0 # Move To LO nop lw k0, 0x74(sp) mthi k0 # Move To HI nop lw k0, 0x78(sp) nop mtc0 k0, C0_STATUS # Status register sll zero, 1 sll zero, 1 sll zero, 1 sll zero, 1 lw k0, 0x7C(sp) nop mtc0 k0, C0_EPC # Exception Program Counter sll zero, 1 sll zero, 1 sll zero, 1 sll zero, 1 addiu sp, 0x80 eret # Exception Return nop .extern _exception_handler .global _exception .type _exception,@function _exception: move a0, sp mfc0 a1, C0_CAUSE # C0_CAUSE of last exception mfc0 a2, C0_EPC # Exception Program Counter la k0, exception_handler jr k0 nop .set reorder