/* SPDX-License-Identifier: GPL-2.0+ */ /* * Copyright (C) 1998 Dan Malek * Copyright (C) 1999 Magnus Damm * Copyright (C) 2000,2001,2002 Wolfgang Denk */ /* 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 #include #include #include #include #include #include #include /* 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 */ . = 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 lis r3, IDC_ENABLE@h /* Enable instruction cache */ 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 */ /*----------------------------------------------------------------------*/ /* * 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 /* set up the stack on top of internal DPRAM */ lis r3, (CFG_SYS_INIT_RAM_ADDR + CFG_SYS_INIT_RAM_SIZE)@h ori r3, r3, (CFG_SYS_INIT_RAM_ADDR + CFG_SYS_INIT_RAM_SIZE)@l stw r0, -4(r3) stw r0, -8(r3) addi r1, r3, -8 bl board_init_f_alloc_reserve addi r1, r3, -8 /* Zeroise the CPM dpram */ lis r4, CONFIG_SYS_IMMR@h ori r4, r4, (0x2000 - 4) li r0, (0x2000 / 4) mtctr r0 li r0, 0 1: stwu r0, 4(r4) bdnz 1b bl board_init_f_init_reserve /* let the C-code set up the rest */ /* */ /* Be careful to keep code relocatable ! */ /*----------------------------------------------------------------------*/ GET_GOT /* initialize GOT access */ lis r3, CONFIG_SYS_IMMR@h bl cpu_init_f /* run low-level CPU init code (from Flash) */ li r3, 0 /* clear boot_flag for calling board_init_f */ 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 /*------------------------------------------------------------------------------*/ /* * 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