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upstream u-boot with additional patches for our devices/boards: https://lists.denx.de/pipermail/u-boot/2017-March/282789.html (AXP crashes) ; Gbit ethernet patch for some LIME2 revisions ; with SPI flash support
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u-boot/arch/arm/cpu/ixp/start.S

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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 <asm-offsets.h>
#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:
ldr pc, _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
_reset: .word reset
_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
*/
.globl _TEXT_BASE
_TEXT_BASE:
.word CONFIG_SYS_TEXT_BASE
/*
* These are defined in the board-specific linker script.
* Subtracting _start from them lets the linker put their
* relative position in the executable instead of leaving
* them null.
*/
.globl _bss_start_ofs
_bss_start_ofs:
.word __bss_start - _start
.globl _bss_end_ofs
_bss_end_ofs:
.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:
/* 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, =CONFIG_SYS_EXP_CS0
ldr r2, =IXP425_EXP_CS0
str r1, [r2]
/* make sure flash is visible at 0 */
mov r1, #CONFIG_SYS_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, =CONFIG_SYS_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, #CONFIG_SYS_SDR_MODE_CONFIG
str r1, [r4]
DELAY_FOR 0x4000, r0
/* send normal operation command */
mov r1, #6
str r1, [r4]
DELAY_FOR 0x4000, 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
/* remove flash mirror at 0x00000000 */
ldr r2, =IXP425_EXP_CFG0
ldr r1, [r2]
bic r1, r1, #0x80000000
str r1, [r2]
/* 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
/* Set initial stackpointer in SDRAM 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
cmp r0, r6
moveq r9, #0 /* no relocation. relocation offset(r9) = 0 */
beq clear_bss /* skip relocation */
mov r1, r6 /* r1 <- scratch for copy_loop */
ldr r3, _bss_start_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
#endif
clear_bss:
#ifndef CONFIG_SPL_BUILD
ldr r0, _bss_start_ofs
ldr r1, _bss_end_ofs
mov r4, r6 /* reloc addr */
add r0, r0, r4
add r1, r1, r4
mov r2, #0x00000000 /* clear */
clbss_l:cmp r0, r1 /* clear loop... */
bhs clbss_e /* if reached end of bss, exit */
str r2, [r0]
add r0, r0, #4
b clbss_l
clbss_e:
bl coloured_LED_init
bl red_led_on
#endif
/*
* We are done. Do not return, instead branch to second part of board
* initialization, now running from RAM.
*/
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
_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
/****************************************************************************/
/* */
/* 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, IRQ_STACK_START_IN
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, IRQ_STACK_START_IN @ setup our mode 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