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uboot-1.1.4-kirkwood/cpu/ixp/start.S
Olaf Rempel f69754bccc u-boot 1.1.4
2024-01-07 23:57:24 +01:00

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/* vi: set ts=8 sw=8 noet: */
/*
* u-boot - Startup Code for XScale IXP
*
* Copyright (C) 2003 Kyle Harris <kharris@nexus-tech.net>
*
* Based on startup code example contained in the
* Intel IXP4xx Programmer's Guide and past u-boot Start.S
* samples.
*
* 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>
#include <asm/arch/ixp425.h>
#define MMU_Control_M 0x001 /* Enable MMU */
#define MMU_Control_A 0x002 /* Enable address alignment faults */
#define MMU_Control_C 0x004 /* Enable cache */
#define MMU_Control_W 0x008 /* Enable write-buffer */
#define MMU_Control_P 0x010 /* Compatability: 32 bit code */
#define MMU_Control_D 0x020 /* Compatability: 32 bit data */
#define MMU_Control_L 0x040 /* Compatability: */
#define MMU_Control_B 0x080 /* Enable Big-Endian */
#define MMU_Control_S 0x100 /* Enable system protection */
#define MMU_Control_R 0x200 /* Enable ROM protection */
#define MMU_Control_I 0x1000 /* Enable Instruction cache */
#define MMU_Control_X 0x2000 /* Set interrupt vectors at 0xFFFF0000 */
#define MMU_Control_Init (MMU_Control_P|MMU_Control_D|MMU_Control_L)
/*
* Macro definitions
*/
/* Delay a bit */
.macro DELAY_FOR cycles, reg0
ldr \reg0, =\cycles
subs \reg0, \reg0, #1
subne pc, pc, #0xc
.endm
/* wait for coprocessor write complete */
.macro CPWAIT reg
mrc p15,0,\reg,c2,c0,0
mov \reg,\reg
sub pc,pc,#4
.endm
.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
*/
_TEXT_BASE:
.word TEXT_BASE
.globl _armboot_start
_armboot_start:
.word _start
/*
* These are defined in the board-specific linker script.
*/
.globl _bss_start
_bss_start:
.word __bss_start
.globl _bss_end
_bss_end:
.word _end
#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:
/* disable mmu, set big-endian */
mov r0, #0xf8
mcr p15, 0, r0, c1, c0, 0
CPWAIT r0
/* invalidate I & D caches & BTB */
mcr p15, 0, r0, c7, c7, 0
CPWAIT r0
/* invalidate I & Data TLB */
mcr p15, 0, r0, c8, c7, 0
CPWAIT r0
/* drain write and fill buffers */
mcr p15, 0, r0, c7, c10, 4
CPWAIT r0
/* disable write buffer coalescing */
mrc p15, 0, r0, c1, c0, 1
orr r0, r0, #1
mcr p15, 0, r0, c1, c0, 1
CPWAIT r0
/* set EXP CS0 to the optimum timing */
ldr r1, =CFG_EXP_CS0
ldr r2, =IXP425_EXP_CS0
str r1, [r2]
/* make sure flash is visible at 0 */
#if 0
ldr r2, =IXP425_EXP_CFG0
ldr r1, [r2]
orr r1, r1, #0x80000000
str r1, [r2]
#endif
mov r1, #CFG_SDR_CONFIG
ldr r2, =IXP425_SDR_CONFIG
str r1, [r2]
/* disable refresh cycles */
mov r1, #0
ldr r3, =IXP425_SDR_REFRESH
str r1, [r3]
/* send nop command */
mov r1, #3
ldr r4, =IXP425_SDR_IR
str r1, [r4]
DELAY_FOR 0x4000, r0
/* set SDRAM internal refresh val */
ldr r1, =CFG_SDRAM_REFRESH_CNT
str r1, [r3]
DELAY_FOR 0x4000, r0
/* send precharge-all command to close all open banks */
mov r1, #2
str r1, [r4]
DELAY_FOR 0x4000, r0
/* provide 8 auto-refresh cycles */
mov r1, #4
mov r5, #8
111: str r1, [r4]
DELAY_FOR 0x100, r0
subs r5, r5, #1
bne 111b
/* set mode register in sdram */
mov r1, #CFG_SDR_MODE_CONFIG
str r1, [r4]
DELAY_FOR 0x4000, r0
/* send normal operation command */
mov r1, #6
str r1, [r4]
DELAY_FOR 0x4000, r0
/* copy */
mov r0, #0
mov r4, r0
add r2, r0, #0x40000
mov r1, #0x10000000
mov r5, r1
30:
ldr r3, [r0], #4
str r3, [r1], #4
cmp r0, r2
bne 30b
/* invalidate I & D caches & BTB */
mcr p15, 0, r0, c7, c7, 0
CPWAIT r0
/* invalidate I & Data TLB */
mcr p15, 0, r0, c8, c7, 0
CPWAIT r0
/* drain write and fill buffers */
mcr p15, 0, r0, c7, c10, 4
CPWAIT r0
/* move flash to 0x50000000 */
ldr r2, =IXP425_EXP_CFG0
ldr r1, [r2]
bic r1, r1, #0x80000000
str r1, [r2]
nop
nop
nop
nop
nop
nop
/* invalidate I & Data TLB */
mcr p15, 0, r0, c8, c7, 0
CPWAIT r0
/* enable I cache */
mrc p15, 0, r0, c1, c0, 0
orr r0, r0, #MMU_Control_I
mcr p15, 0, r0, c1, c0, 0
CPWAIT r0
mrs r0,cpsr /* set the cpu to SVC32 mode */
bic r0,r0,#0x1f /* (superviser mode, M=10011) */
orr r0,r0,#0x13
msr cpsr,r0
#ifndef CONFIG_SKIP_RELOCATE_UBOOT
relocate: /* relocate U-Boot to RAM */
adr r0, _start /* r0 <- current position of code */
ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
cmp r0, r1 /* don't reloc during debug */
beq stack_setup
ldr r2, _armboot_start
ldr r3, _bss_start
sub r2, r3, r2 /* r2 <- size of armboot */
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
#endif /* CONFIG_SKIP_RELOCATE_UBOOT */
/* Set up the stack */
stack_setup:
ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */
sub r0, r0, #CFG_MALLOC_LEN /* malloc area */
sub r0, r0, #CFG_GBL_DATA_SIZE /* bdinfo */
#ifdef CONFIG_USE_IRQ
sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
#endif
sub sp, r0, #12 /* leave 3 words for abort-stack */
clear_bss:
ldr r0, _bss_start /* find start of bss segment */
ldr r1, _bss_end /* stop here */
mov r2, #0x00000000 /* clear */
clbss_l:str r2, [r0] /* clear loop... */
add r0, r0, #4
cmp r0, r1
ble clbss_l
ldr pc, _start_armboot
_start_armboot: .word start_armboot
/****************************************************************************/
/* */
/* 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_start
sub r2, r2, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN)
sub r2, r2, #(CFG_GBL_DATA_SIZE+8) @ set base 2 words into abort stack
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_start @ setup our mode stack
sub r13, r13, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN)
sub r13, r13, #(CFG_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
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
/****************************************************************************/
/* */
/* Reset function: Use Watchdog to reset */
/* */
/****************************************************************************/
.align 5
.globl reset_cpu
reset_cpu:
ldr r1, =0x482e
ldr r2, =IXP425_OSWK
str r1, [r2]
ldr r1, =0x0fff
ldr r2, =IXP425_OSWT
str r1, [r2]
ldr r1, =0x5
ldr r2, =IXP425_OSWE
str r1, [r2]
b reset_endless
reset_endless:
b reset_endless
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