/* * Copyright (C) 1998 Dan Malek * Copyright (C) 1999 Magnus Damm * Copyright (C) 2000, 2001, 2002 Wolfgang Denk * Copyright (C) 2003 Martin Winistoerfer, martinwinistoerfer@gmx.ch. * * 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 */ /* * File: start.S * * Discription: startup code * */ #include #include #include #define CONFIG_5xx 1 /* needed for Linux kernel header files */ #define _LINUX_CONFIG_H 1 /* avoid reading Linux autoconf.h file */ #include #include #include #include #ifndef CONFIG_IDENT_STRING #define CONFIG_IDENT_STRING "" #endif /* We don't have a MMU. */ #undef MSR_KERNEL #define MSR_KERNEL ( MSR_ME | MSR_RI ) /* Machine Check and Recoverable Interr. */ /* * Set up GOT: Global Offset Table * * Use r14 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 " (", __DATE__, " - ", __TIME__, ")" .ascii CONFIG_IDENT_STRING, "\0" . = EXC_OFF_SYS_RESET .globl _start _start: mfspr r3, 638 li r4, CFG_ISB /* Set ISB bit */ or r3, r3, r4 mtspr 638, r3 li r21, BOOTFLAG_COLD /* Normal Power-On: Boot from FLASH */ b boot_cold . = EXC_OFF_SYS_RESET + 0x20 .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 */ /* 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 /* * Calculate absolute address in FLASH and jump there *----------------------------------------------------------------------*/ lis r3, CFG_MONITOR_BASE@h ori r3, r3, CFG_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, CFG_IMMR@h /* Pass IMMR as arg1 to C routine */ lis r2, CFG_INIT_SP_ADDR@h ori r1, r2, CFG_INIT_SP_ADDR@l /* Set up the stack in internal SRAM */ /* 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) for maximum * performance. */ li r2, 0x0007 mtspr ICTRL, r2 /* Set up debug mode entry */ lis r2, CFG_DER@h ori r2, r2, CFG_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 mfspr r4,DAR stw r4,_DAR(r21) mfspr r5,DSISR stw r5,_DSISR(r21) addi r3,r1,STACK_FRAME_OVERHEAD li r20,MSR_KERNEL rlwimi r20,r23,0,16,16 /* copy EE bit from saved MSR */ lwz r6,GOT(transfer_to_handler) mtlr r6 blrl .L_Alignment: .long AlignmentException - _start + EXC_OFF_SYS_RESET .long int_return - _start + EXC_OFF_SYS_RESET /* Program check exception */ . = 0x700 ProgramCheck: EXCEPTION_PROLOG addi r3,r1,STACK_FRAME_OVERHEAD li r20,MSR_KERNEL rlwimi r20,r23,0,16,16 /* copy EE bit from saved MSR */ lwz r6,GOT(transfer_to_handler) mtlr r6 blrl .L_ProgramCheck: .long ProgramCheckException - _start + EXC_OFF_SYS_RESET .long int_return - _start + EXC_OFF_SYS_RESET /* FPU on MPC5xx available. We will use it later. */ 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 /* * 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 /*------------------------------------------------------------------------------*/ /* * 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 in SRAM */ mr r9, r4 /* Save copy of global data pointer in SRAM */ mr r10, r5 /* Save copy of monitor destination Address in SRAM */ mr r3, r5 /* Destination Address */ lis r4, CFG_MONITOR_BASE@h /* Source Address */ ori r4, r4, CFG_MONITOR_BASE@l lwz r5, GOT(__init_end) sub r5, r5, r4 /* * Fix GOT pointer: * * New GOT-PTR = (old GOT-PTR - CFG_MONITOR_BASE) + Destination Address * * Offset: */ sub r15, r10, r4 /* First our own GOT */ add r14, r14, r15 /* the 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 4f /* 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 4: sync 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, r14 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) add r0,r0,r11 stw r0,0(r3) bdnz 1b /* * Now adjust the fixups and the pointers to the fixups * in case we need to move ourselves again. */ 2: 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: 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 */ mflr r4 /* save link register */ 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 /* * Function: relocate entries for one exception vector */ trap_reloc: lwz r0, 0(r7) /* hdlr ... */ add r0, r0, r3 /* ... += dest_addr */ stw r0, 0(r7) lwz r0, 4(r7) /* int_return ... */ add r0, r0, r3 /* ... += dest_addr */ stw r0, 4(r7) sync isync blr