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Diffstat (limited to 'arch/powerpc/cpu/mpc8xx/start.S')
| -rw-r--r-- | arch/powerpc/cpu/mpc8xx/start.S | 684 |
1 files changed, 684 insertions, 0 deletions
diff --git a/arch/powerpc/cpu/mpc8xx/start.S b/arch/powerpc/cpu/mpc8xx/start.S new file mode 100644 index 0000000..7cf602f --- /dev/null +++ b/arch/powerpc/cpu/mpc8xx/start.S @@ -0,0 +1,684 @@ +/* + * 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 <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> + +#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(_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 + li r21, BOOTFLAG_COLD /* Normal Power-On: Boot from FLASH */ + b boot_cold + + . = EXC_OFF_SYS_RESET + 0x10 + + .globl _start_warm +_start_warm: + li r21, BOOTFLAG_WARM /* Software reboot */ + b boot_warm + +boot_cold: +boot_warm: + + /* 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) */ + + mr r3, r21 + /* r3: BOOTFLAG */ + bl board_init_f /* run 1st part of board init code (from Flash) */ + + + .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 + add r0,r0,r11 + stw r10,0(r3) + stw r0,0(r4) + bdnz 3b +4: +clear_bss: + /* + * Now clear BSS segment + */ + lwz r3,GOT(__bss_start) + lwz r4,GOT(_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 |