/* 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 <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: b 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 _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 */ _TEXT_BASE: .word TEXT_BASE .globl _armboot_start _armboot_start: .word _start /* * These are defined in the board-specific linker script. */ .globl _bss_start _bss_start: .word __bss_start .globl _bss_end _bss_end: .word _end #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 /****************************************************************************/ /* */ /* 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, =CFG_EXP_CS0 ldr r2, =IXP425_EXP_CS0 str r1, [r2] /* make sure flash is visible at 0 */ #if 0 ldr r2, =IXP425_EXP_CFG0 ldr r1, [r2] orr r1, r1, #0x80000000 str r1, [r2] #endif mov r1, #CFG_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, =CFG_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, #CFG_SDR_MODE_CONFIG str r1, [r4] DELAY_FOR 0x4000, r0 /* send normal operation command */ mov r1, #6 str r1, [r4] DELAY_FOR 0x4000, r0 /* copy */ mov r0, #0 mov r4, r0 add r2, r0, #0x40000 mov r1, #0x10000000 mov r5, r1 30: ldr r3, [r0], #4 str r3, [r1], #4 cmp r0, r2 bne 30b /* 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 /* move flash to 0x50000000 */ ldr r2, =IXP425_EXP_CFG0 ldr r1, [r2] bic r1, r1, #0x80000000 str r1, [r2] nop nop nop nop nop nop /* 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 #ifndef CONFIG_SKIP_RELOCATE_UBOOT relocate: /* relocate U-Boot to RAM */ adr r0, _start /* r0 <- current position of code */ ldr r1, _TEXT_BASE /* test if we run from flash or RAM */ cmp r0, r1 /* don't reloc during debug */ beq stack_setup ldr r2, _armboot_start ldr r3, _bss_start sub r2, r3, r2 /* r2 <- size of armboot */ add r2, r0, r2 /* r2 <- source end address */ copy_loop: ldmia r0!, {r3-r10} /* copy from source address [r0] */ stmia r1!, {r3-r10} /* copy to target address [r1] */ cmp r0, r2 /* until source end addreee [r2] */ ble copy_loop #endif /* CONFIG_SKIP_RELOCATE_UBOOT */ /* Set up the stack */ stack_setup: ldr r0, _TEXT_BASE /* upper 128 KiB: relocated uboot */ sub r0, r0, #CFG_MALLOC_LEN /* malloc area */ sub r0, r0, #CFG_GBL_DATA_SIZE /* bdinfo */ #ifdef CONFIG_USE_IRQ sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ) #endif sub sp, r0, #12 /* leave 3 words for abort-stack */ clear_bss: ldr r0, _bss_start /* find start of bss segment */ ldr r1, _bss_end /* stop here */ mov r2, #0x00000000 /* clear */ clbss_l:str r2, [r0] /* clear loop... */ add r0, r0, #4 cmp r0, r1 ble clbss_l ldr pc, _start_armboot _start_armboot: .word start_armboot /****************************************************************************/ /* */ /* 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, _armboot_start sub r2, r2, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN) sub r2, r2, #(CFG_GBL_DATA_SIZE+8) @ set base 2 words into abort stack 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, _armboot_start @ setup our mode stack sub r13, r13, #(CONFIG_STACKSIZE+CFG_MALLOC_LEN) sub r13, r13, #(CFG_GBL_DATA_SIZE+8) @ reserved a couple spots in abort 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