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Diffstat (limited to 'cpu/xscale/start.S')
| -rw-r--r-- | cpu/xscale/start.S | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/cpu/xscale/start.S b/cpu/xscale/start.S new file mode 100644 index 0000000..f1049a8 --- /dev/null +++ b/cpu/xscale/start.S @@ -0,0 +1,412 @@ +/* + * armboot - Startup Code for XScale + * + * Copyright (C) 1998 Dan Malek <dmalek@jlc.net> + * Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se> + * Copyright (C) 2000 Wolfgang Denk <wd@denx.de> + * Copyright (c) 2001 Alex Züpke <azu@sysgo.de> + * Copyright (c) 2002 Kyle Harris <kharris@nexus-tech.net> + * + * 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 <version.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 + +_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 + + .balignl 16,0xdeadbeef + + +/* + * Startup Code (reset vector) + * + * do important init only if we don't start from memory! + * - relocate armboot to ram + * - setup stack + * - jump to second stage + */ + +/* + * CFG_MEM_END is in the board dependent config-file (configs/config_BOARD.h) + */ +_TEXT_BASE: + .word TEXT_BASE + +.globl _armboot_start +_armboot_start: + .word _start + +/* + * Note: _armboot_end_data and _armboot_end are defined + * by the (board-dependent) linker script. + * _armboot_end_data is the first usable FLASH address after armboot + */ +.globl _armboot_end_data +_armboot_end_data: + .word armboot_end_data +.globl _armboot_end +_armboot_end: + .word armboot_end + +/* + * _armboot_real_end is the first usable RAM address behind armboot + * and the various stacks + */ +.globl _armboot_real_end +_armboot_real_end: + .word 0x0badc0de + +/* + * We relocate uboot to this address (end of RAM - 128 KiB) + */ +.globl _uboot_reloc +_uboot_reloc: + .word CFG_DRAM_BASE + CFG_DRAM_SIZE - CFG_MONITOR_LEN + +#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 + + +/****************************************************************************/ +/* */ +/* the actual reset code */ +/* */ +/****************************************************************************/ + +reset: + mrs r0,cpsr /* set the cpu to SVC32 mode */ + bic r0,r0,#0x1f /* (superviser mode, M=10011) */ + orr r0,r0,#0x13 + msr cpsr,r0 + + bl cpu_init_crit /* we do sys-critical inits */ + +relocate: /* relocate U-Boot to RAM */ + adr r0, _start /* r0 <- current position of code */ + ldr r2, _armboot_start + ldr r3, _armboot_end + sub r2, r3, r2 /* r2 <- size of armboot */ +/* ldr r1, _uboot_reloc / * r1 <- destination address */ + ldr r1, _TEXT_BASE + add r2, r0, r2 /* r2 <- source end address */ + +copy_loop: + ldmia r0!, {r3-r10} /* copy from source address [r0] */ + stmia r1!, {r3-r10} /* copy to target address [r1] */ + cmp r0, r2 /* until source end addreee [r2] */ + ble copy_loop + + /* Set up the stack */ + ldr r0, _uboot_reloc /* upper 128 KiB: relocated uboot */ + sub r0, r0, #CFG_MALLOC_LEN /* malloc area */ + /* FIXME: bdinfo should be here */ + sub sp, r0, #12 /* leave 3 words for abort-stack */ + + ldr pc, _start_armboot + +_start_armboot: .word start_armboot + + +/****************************************************************************/ +/* */ +/* CPU_init_critical registers */ +/* */ +/* - setup important registers */ +/* - setup memory timing */ +/* */ +/****************************************************************************/ + + /* Interrupt-Controller base address */ +IC_BASE: .word 0x40d00000 +#define ICMR 0x04 + +/* Reset-Controller */ +RST_BASE: .word 0x40f00030 +#define RCSR 0x00 + + + /* Clock Manager Registers */ +CC_BASE: .word 0x41300000 +#define CCCR 0x00 +cpuspeed: .word CFG_CPUSPEED + + /* RS: ??? */ + .macro CPWAIT + mrc p15,0,r0,c2,c0,0 + mov r0,r0 + sub pc,pc,#4 + .endm + + +cpu_init_crit: + + /* mask all IRQs */ + ldr r0, IC_BASE + mov r1, #0x00 + str r1, [r0, #ICMR] + + /* set clock speed */ + ldr r0, CC_BASE + ldr r1, cpuspeed + str r1, [r0, #CCCR] + + /* + * before relocating, we have to setup RAM timing + * because memory timing is board-dependend, you will + * find a memsetup.S in your board directory. + */ + mov ip, lr + bl memsetup + mov lr, ip + + /* Memory interfaces are working. Disable MMU and enable I-cache. */ + + ldr r0, =0x2001 /* enable access to all coproc. */ + mcr p15, 0, r0, c15, c1, 0 + CPWAIT + + mcr p15, 0, r0, c7, c10, 4 /* drain the write & fill buffers */ + CPWAIT + + mcr p15, 0, r0, c7, c7, 0 /* flush Icache, Dcache and BTB */ + CPWAIT + + mcr p15, 0, r0, c8, c7, 0 /* flush instuction and data TLBs */ + CPWAIT + + /* Enable the Icache */ +/* + mrc p15, 0, r0, c1, c0, 0 + orr r0, r0, #0x1800 + mcr p15, 0, r0, c1, c0, 0 + CPWAIT +*/ + mov pc, lr + + +/****************************************************************************/ +/* */ +/* 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 + + /* use bad_save_user_regs for abort/prefetch/undef/swi ... */ + + .macro bad_save_user_regs + sub sp, sp, #S_FRAME_SIZE + stmia sp, {r0 - r12} /* Calling r0-r12 */ + add r8, sp, #S_PC + + ldr r2, _armboot_end + add r2, r2, #CONFIG_STACKSIZE + sub r2, r2, #8 + ldmia r2, {r2 - r4} /* get pc, cpsr, old_r0 */ + add r0, sp, #S_FRAME_SIZE /* restore sp_SVC */ + + add r5, sp, #S_SP + mov r1, lr + stmia r5, {r0 - r4} /* save sp_SVC, lr_SVC, pc, cpsr, old_r */ + mov r0, sp + .endm + + + /* use irq_save_user_regs / irq_restore_user_regs for */ + /* IRQ/FIQ handling */ + + .macro irq_save_user_regs + sub sp, sp, #S_FRAME_SIZE + stmia sp, {r0 - r12} /* Calling r0-r12 */ + 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, _armboot_end @ setup our mode stack + add r13, r13, #CONFIG_STACKSIZE @ resides at top of normal stack + sub r13, r13, #8 + + str lr, [r13] @ save caller lr / spsr + mrs lr, spsr + str lr, [r13, #4] + + mov r13, #MODE_SVC @ prepare SVC-Mode + msr spsr_c, r13 + mov lr, pc + movs pc, lr + .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 + 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 + irq_save_user_regs /* someone ought to write a more */ + bl do_fiq /* effiction fiq_save_user_regs */ + 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 + +/* + * FIXME How do we reset??? Watchdog timeout?? + */ + .align 5 +.globl reset_cpu +reset_cpu: + /* + ldr r0, RST_BASE + mov r1, #0x0 @ set bit 3-0 ... + str r1, [r0, #RCSR] @ ... to clear in RCSR + mov r1, #0x1 + str r1, [r0, #RCSR] @ and perform reset + */ + b reset_cpu @ silly, but repeat endlessly + |