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u-boot/arch/powerpc/cpu/mpc8xx/start.S
Po-Yu Chuang 44c6e6591c rename _end to __bss_end__ 
Currently, _end is used for end of BSS section.  We want _end to mean
end of u-boot image, so we rename _end to __bss_end__ first.

Signed-off-by: Po-Yu Chuang <ratbert@faraday-tech.com>
2011-03-27 19:18:37 +02:00

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ArmAsm
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/*
* Copyright (C) 1998 Dan Malek <dmalek@jlc.net>
* Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
* Copyright (C) 2000,2001,2002 Wolfgang Denk <wd@denx.de>
*
* 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
*/
/* U-Boot - Startup Code for PowerPC based Embedded Boards
*
*
* The processor starts at 0x00000100 and the code is executed
* from flash. The code is organized to be at an other address
* in memory, but as long we don't jump around before relocating,
* board_init lies at a quite high address and when the cpu has
* jumped there, everything is ok.
* This works because the cpu gives the FLASH (CS0) the whole
* address space at startup, and board_init lies as a echo of
* the flash somewhere up there in the memory map.
*
* board_init will change CS0 to be positioned at the correct
* address and (s)dram will be positioned at address 0
*/
#include <asm-offsets.h>
#include <config.h>
#include <mpc8xx.h>
#include <timestamp.h>
#include <version.h>
#define CONFIG_8xx 1 /* needed for Linux kernel header files */
#define _LINUX_CONFIG_H 1 /* avoid reading Linux autoconf.h file */
#include <ppc_asm.tmpl>
#include <ppc_defs.h>
#include <asm/cache.h>
#include <asm/mmu.h>
#include <asm/u-boot.h>
#ifndef CONFIG_IDENT_STRING
#define CONFIG_IDENT_STRING ""
#endif
/* We don't want the MMU yet.
*/
#undef MSR_KERNEL
#define MSR_KERNEL ( MSR_ME | MSR_RI ) /* Machine Check and Recoverable Interr. */
/*
* Set up GOT: Global Offset Table
*
* Use r12 to access the GOT
*/
START_GOT
GOT_ENTRY(_GOT2_TABLE_)
GOT_ENTRY(_FIXUP_TABLE_)
GOT_ENTRY(_start)
GOT_ENTRY(_start_of_vectors)
GOT_ENTRY(_end_of_vectors)
GOT_ENTRY(transfer_to_handler)
GOT_ENTRY(__init_end)
GOT_ENTRY(__bss_end__)
GOT_ENTRY(__bss_start)
END_GOT
/*
* r3 - 1st arg to board_init(): IMMP pointer
* r4 - 2nd arg to board_init(): boot flag
*/
.text
.long 0x27051956 /* U-Boot Magic Number */
.globl version_string
version_string:
.ascii U_BOOT_VERSION
.ascii " (", U_BOOT_DATE, " - ", U_BOOT_TIME, ")"
.ascii CONFIG_IDENT_STRING, "\0"
. = EXC_OFF_SYS_RESET
.globl _start
_start:
lis r3, CONFIG_SYS_IMMR@h /* position IMMR */
mtspr 638, r3
/* Initialize machine status; enable machine check interrupt */
/*----------------------------------------------------------------------*/
li r3, MSR_KERNEL /* Set ME, RI flags */
mtmsr r3
mtspr SRR1, r3 /* Make SRR1 match MSR */
mfspr r3, ICR /* clear Interrupt Cause Register */
/* Initialize debug port registers */
/*----------------------------------------------------------------------*/
xor r0, r0, r0 /* Clear R0 */
mtspr LCTRL1, r0 /* Initialize debug port regs */
mtspr LCTRL2, r0
mtspr COUNTA, r0
mtspr COUNTB, r0
/* Reset the caches */
/*----------------------------------------------------------------------*/
mfspr r3, IC_CST /* Clear error bits */
mfspr r3, DC_CST
lis r3, IDC_UNALL@h /* Unlock all */
mtspr IC_CST, r3
mtspr DC_CST, r3
lis r3, IDC_INVALL@h /* Invalidate all */
mtspr IC_CST, r3
mtspr DC_CST, r3
lis r3, IDC_DISABLE@h /* Disable data cache */
mtspr DC_CST, r3
#if !defined(CONFIG_SYS_DELAYED_ICACHE)
/* On IP860 and PCU E,
* we cannot enable IC yet
*/
lis r3, IDC_ENABLE@h /* Enable instruction cache */
#endif
mtspr IC_CST, r3
/* invalidate all tlb's */
/*----------------------------------------------------------------------*/
tlbia
isync
/*
* Calculate absolute address in FLASH and jump there
*----------------------------------------------------------------------*/
lis r3, CONFIG_SYS_MONITOR_BASE@h
ori r3, r3, CONFIG_SYS_MONITOR_BASE@l
addi r3, r3, in_flash - _start + EXC_OFF_SYS_RESET
mtlr r3
blr
in_flash:
/* initialize some SPRs that are hard to access from C */
/*----------------------------------------------------------------------*/
lis r3, CONFIG_SYS_IMMR@h /* pass IMMR as arg1 to C routine */
ori r1, r3, CONFIG_SYS_INIT_SP_OFFSET /* set up the stack in internal DPRAM */
/* Note: R0 is still 0 here */
stwu r0, -4(r1) /* clear final stack frame so that */
stwu r0, -4(r1) /* stack backtraces terminate cleanly */
/*
* Disable serialized ifetch and show cycles
* (i.e. set processor to normal mode).
* This is also a silicon bug workaround, see errata
*/
li r2, 0x0007
mtspr ICTRL, r2
/* Set up debug mode entry */
lis r2, CONFIG_SYS_DER@h
ori r2, r2, CONFIG_SYS_DER@l
mtspr DER, r2
/* let the C-code set up the rest */
/* */
/* Be careful to keep code relocatable ! */
/*----------------------------------------------------------------------*/
GET_GOT /* initialize GOT access */
/* r3: IMMR */
bl cpu_init_f /* run low-level CPU init code (from Flash) */
bl board_init_f /* run 1st part of board init code (from Flash) */
/* NOTREACHED - board_init_f() does not return */
.globl _start_of_vectors
_start_of_vectors:
/* Machine check */
STD_EXCEPTION(0x200, MachineCheck, MachineCheckException)
/* Data Storage exception. "Never" generated on the 860. */
STD_EXCEPTION(0x300, DataStorage, UnknownException)
/* Instruction Storage exception. "Never" generated on the 860. */
STD_EXCEPTION(0x400, InstStorage, UnknownException)
/* External Interrupt exception. */
STD_EXCEPTION(0x500, ExtInterrupt, external_interrupt)
/* Alignment exception. */
. = 0x600
Alignment:
EXCEPTION_PROLOG(SRR0, SRR1)
mfspr r4,DAR
stw r4,_DAR(r21)
mfspr r5,DSISR
stw r5,_DSISR(r21)
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_TEMPLATE(Alignment, AlignmentException, MSR_KERNEL, COPY_EE)
/* Program check exception */
. = 0x700
ProgramCheck:
EXCEPTION_PROLOG(SRR0, SRR1)
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_TEMPLATE(ProgramCheck, ProgramCheckException,
MSR_KERNEL, COPY_EE)
/* No FPU on MPC8xx. This exception is not supposed to happen.
*/
STD_EXCEPTION(0x800, FPUnavailable, UnknownException)
/* I guess we could implement decrementer, and may have
* to someday for timekeeping.
*/
STD_EXCEPTION(0x900, Decrementer, timer_interrupt)
STD_EXCEPTION(0xa00, Trap_0a, UnknownException)
STD_EXCEPTION(0xb00, Trap_0b, UnknownException)
STD_EXCEPTION(0xc00, SystemCall, UnknownException)
STD_EXCEPTION(0xd00, SingleStep, UnknownException)
STD_EXCEPTION(0xe00, Trap_0e, UnknownException)
STD_EXCEPTION(0xf00, Trap_0f, UnknownException)
/* On the MPC8xx, this is a software emulation interrupt. It occurs
* for all unimplemented and illegal instructions.
*/
STD_EXCEPTION(0x1000, SoftEmu, SoftEmuException)
STD_EXCEPTION(0x1100, InstructionTLBMiss, UnknownException)
STD_EXCEPTION(0x1200, DataTLBMiss, UnknownException)
STD_EXCEPTION(0x1300, InstructionTLBError, UnknownException)
STD_EXCEPTION(0x1400, DataTLBError, UnknownException)
STD_EXCEPTION(0x1500, Reserved5, UnknownException)
STD_EXCEPTION(0x1600, Reserved6, UnknownException)
STD_EXCEPTION(0x1700, Reserved7, UnknownException)
STD_EXCEPTION(0x1800, Reserved8, UnknownException)
STD_EXCEPTION(0x1900, Reserved9, UnknownException)
STD_EXCEPTION(0x1a00, ReservedA, UnknownException)
STD_EXCEPTION(0x1b00, ReservedB, UnknownException)
STD_EXCEPTION(0x1c00, DataBreakpoint, UnknownException)
STD_EXCEPTION(0x1d00, InstructionBreakpoint, DebugException)
STD_EXCEPTION(0x1e00, PeripheralBreakpoint, UnknownException)
STD_EXCEPTION(0x1f00, DevPortBreakpoint, UnknownException)
.globl _end_of_vectors
_end_of_vectors:
. = 0x2000
/*
* This code finishes saving the registers to the exception frame
* and jumps to the appropriate handler for the exception.
* Register r21 is pointer into trap frame, r1 has new stack pointer.
*/
.globl transfer_to_handler
transfer_to_handler:
stw r22,_NIP(r21)
lis r22,MSR_POW@h
andc r23,r23,r22
stw r23,_MSR(r21)
SAVE_GPR(7, r21)
SAVE_4GPRS(8, r21)
SAVE_8GPRS(12, r21)
SAVE_8GPRS(24, r21)
mflr r23
andi. r24,r23,0x3f00 /* get vector offset */
stw r24,TRAP(r21)
li r22,0
stw r22,RESULT(r21)
mtspr SPRG2,r22 /* r1 is now kernel sp */
lwz r24,0(r23) /* virtual address of handler */
lwz r23,4(r23) /* where to go when done */
mtspr SRR0,r24
mtspr SRR1,r20
mtlr r23
SYNC
rfi /* jump to handler, enable MMU */
int_return:
mfmsr r28 /* Disable interrupts */
li r4,0
ori r4,r4,MSR_EE
andc r28,r28,r4
SYNC /* Some chip revs need this... */
mtmsr r28
SYNC
lwz r2,_CTR(r1)
lwz r0,_LINK(r1)
mtctr r2
mtlr r0
lwz r2,_XER(r1)
lwz r0,_CCR(r1)
mtspr XER,r2
mtcrf 0xFF,r0
REST_10GPRS(3, r1)
REST_10GPRS(13, r1)
REST_8GPRS(23, r1)
REST_GPR(31, r1)
lwz r2,_NIP(r1) /* Restore environment */
lwz r0,_MSR(r1)
mtspr SRR0,r2
mtspr SRR1,r0
lwz r0,GPR0(r1)
lwz r2,GPR2(r1)
lwz r1,GPR1(r1)
SYNC
rfi
/* Cache functions.
*/
.globl icache_enable
icache_enable:
SYNC
lis r3, IDC_INVALL@h
mtspr IC_CST, r3
lis r3, IDC_ENABLE@h
mtspr IC_CST, r3
blr
.globl icache_disable
icache_disable:
SYNC
lis r3, IDC_DISABLE@h
mtspr IC_CST, r3
blr
.globl icache_status
icache_status:
mfspr r3, IC_CST
srwi r3, r3, 31 /* >>31 => select bit 0 */
blr
.globl dcache_enable
dcache_enable:
#if 0
SYNC
#endif
#if 1
lis r3, 0x0400 /* Set cache mode with MMU off */
mtspr MD_CTR, r3
#endif
lis r3, IDC_INVALL@h
mtspr DC_CST, r3
#if 0
lis r3, DC_SFWT@h
mtspr DC_CST, r3
#endif
lis r3, IDC_ENABLE@h
mtspr DC_CST, r3
blr
.globl dcache_disable
dcache_disable:
SYNC
lis r3, IDC_DISABLE@h
mtspr DC_CST, r3
lis r3, IDC_INVALL@h
mtspr DC_CST, r3
blr
.globl dcache_status
dcache_status:
mfspr r3, DC_CST
srwi r3, r3, 31 /* >>31 => select bit 0 */
blr
.globl dc_read
dc_read:
mtspr DC_ADR, r3
mfspr r3, DC_DAT
blr
/*
* unsigned int get_immr (unsigned int mask)
*
* return (mask ? (IMMR & mask) : IMMR);
*/
.globl get_immr
get_immr:
mr r4,r3 /* save mask */
mfspr r3, IMMR /* IMMR */
cmpwi 0,r4,0 /* mask != 0 ? */
beq 4f
and r3,r3,r4 /* IMMR & mask */
4:
blr
.globl get_pvr
get_pvr:
mfspr r3, PVR
blr
.globl wr_ic_cst
wr_ic_cst:
mtspr IC_CST, r3
blr
.globl rd_ic_cst
rd_ic_cst:
mfspr r3, IC_CST
blr
.globl wr_ic_adr
wr_ic_adr:
mtspr IC_ADR, r3
blr
.globl wr_dc_cst
wr_dc_cst:
mtspr DC_CST, r3
blr
.globl rd_dc_cst
rd_dc_cst:
mfspr r3, DC_CST
blr
.globl wr_dc_adr
wr_dc_adr:
mtspr DC_ADR, r3
blr
/*------------------------------------------------------------------------------*/
/*
* void relocate_code (addr_sp, gd, addr_moni)
*
* This "function" does not return, instead it continues in RAM
* after relocating the monitor code.
*
* r3 = dest
* r4 = src
* r5 = length in bytes
* r6 = cachelinesize
*/
.globl relocate_code
relocate_code:
mr r1, r3 /* Set new stack pointer */
mr r9, r4 /* Save copy of Global Data pointer */
mr r10, r5 /* Save copy of Destination Address */
GET_GOT
mr r3, r5 /* Destination Address */
lis r4, CONFIG_SYS_MONITOR_BASE@h /* Source Address */
ori r4, r4, CONFIG_SYS_MONITOR_BASE@l
lwz r5, GOT(__init_end)
sub r5, r5, r4
li r6, CONFIG_SYS_CACHELINE_SIZE /* Cache Line Size */
/*
* Fix GOT pointer:
*
* New GOT-PTR = (old GOT-PTR - CONFIG_SYS_MONITOR_BASE) + Destination Address
*
* Offset:
*/
sub r15, r10, r4
/* First our own GOT */
add r12, r12, r15
/* then the one used by the C code */
add r30, r30, r15
/*
* Now relocate code
*/
cmplw cr1,r3,r4
addi r0,r5,3
srwi. r0,r0,2
beq cr1,4f /* In place copy is not necessary */
beq 7f /* Protect against 0 count */
mtctr r0
bge cr1,2f
la r8,-4(r4)
la r7,-4(r3)
1: lwzu r0,4(r8)
stwu r0,4(r7)
bdnz 1b
b 4f
2: slwi r0,r0,2
add r8,r4,r0
add r7,r3,r0
3: lwzu r0,-4(r8)
stwu r0,-4(r7)
bdnz 3b
/*
* Now flush the cache: note that we must start from a cache aligned
* address. Otherwise we might miss one cache line.
*/
4: cmpwi r6,0
add r5,r3,r5
beq 7f /* Always flush prefetch queue in any case */
subi r0,r6,1
andc r3,r3,r0
mr r4,r3
5: dcbst 0,r4
add r4,r4,r6
cmplw r4,r5
blt 5b
sync /* Wait for all dcbst to complete on bus */
mr r4,r3
6: icbi 0,r4
add r4,r4,r6
cmplw r4,r5
blt 6b
7: sync /* Wait for all icbi to complete on bus */
isync
/*
* We are done. Do not return, instead branch to second part of board
* initialization, now running from RAM.
*/
addi r0, r10, in_ram - _start + EXC_OFF_SYS_RESET
mtlr r0
blr
in_ram:
/*
* Relocation Function, r12 point to got2+0x8000
*
* Adjust got2 pointers, no need to check for 0, this code
* already puts a few entries in the table.
*/
li r0,__got2_entries@sectoff@l
la r3,GOT(_GOT2_TABLE_)
lwz r11,GOT(_GOT2_TABLE_)
mtctr r0
sub r11,r3,r11
addi r3,r3,-4
1: lwzu r0,4(r3)
cmpwi r0,0
beq- 2f
add r0,r0,r11
stw r0,0(r3)
2: bdnz 1b
/*
* Now adjust the fixups and the pointers to the fixups
* in case we need to move ourselves again.
*/
li r0,__fixup_entries@sectoff@l
lwz r3,GOT(_FIXUP_TABLE_)
cmpwi r0,0
mtctr r0
addi r3,r3,-4
beq 4f
3: lwzu r4,4(r3)
lwzux r0,r4,r11
cmpwi r0,0
add r0,r0,r11
stw r4,0(r3)
beq- 5f
stw r0,0(r4)
5: bdnz 3b
4:
clear_bss:
/*
* Now clear BSS segment
*/
lwz r3,GOT(__bss_start)
lwz r4,GOT(__bss_end__)
cmplw 0, r3, r4
beq 6f
li r0, 0
5:
stw r0, 0(r3)
addi r3, r3, 4
cmplw 0, r3, r4
bne 5b
6:
mr r3, r9 /* Global Data pointer */
mr r4, r10 /* Destination Address */
bl board_init_r
/*
* Copy exception vector code to low memory
*
* r3: dest_addr
* r7: source address, r8: end address, r9: target address
*/
.globl trap_init
trap_init:
mflr r4 /* save link register */
GET_GOT
lwz r7, GOT(_start)
lwz r8, GOT(_end_of_vectors)
li r9, 0x100 /* reset vector always at 0x100 */
cmplw 0, r7, r8
bgelr /* return if r7>=r8 - just in case */
1:
lwz r0, 0(r7)
stw r0, 0(r9)
addi r7, r7, 4
addi r9, r9, 4
cmplw 0, r7, r8
bne 1b
/*
* relocate `hdlr' and `int_return' entries
*/
li r7, .L_MachineCheck - _start + EXC_OFF_SYS_RESET
li r8, Alignment - _start + EXC_OFF_SYS_RESET
2:
bl trap_reloc
addi r7, r7, 0x100 /* next exception vector */
cmplw 0, r7, r8
blt 2b
li r7, .L_Alignment - _start + EXC_OFF_SYS_RESET
bl trap_reloc
li r7, .L_ProgramCheck - _start + EXC_OFF_SYS_RESET
bl trap_reloc
li r7, .L_FPUnavailable - _start + EXC_OFF_SYS_RESET
li r8, SystemCall - _start + EXC_OFF_SYS_RESET
3:
bl trap_reloc
addi r7, r7, 0x100 /* next exception vector */
cmplw 0, r7, r8
blt 3b
li r7, .L_SingleStep - _start + EXC_OFF_SYS_RESET
li r8, _end_of_vectors - _start + EXC_OFF_SYS_RESET
4:
bl trap_reloc
addi r7, r7, 0x100 /* next exception vector */
cmplw 0, r7, r8
blt 4b
mtlr r4 /* restore link register */
blr
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