/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * $Id$ * * Copyright (C) 2008 by Karl Kurbjun * * Arm bootloader and startup code based on startup.s from the iPodLinux loader * Copyright (c) 2003, Daniel Palffy (dpalffy (at) rainstorm.org) * Copyright (c) 2005, Bernard Leach * * All files in this archive are subject to the GNU General Public License. * See the file COPYING in the source tree root for full license agreement. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/ #include "config.h" #include "cpu.h" /* Exception Handlers */ .section .vectors,"ax",%progbits .code 32 .global vectors vectors: b start b undef_instr_handler b software_int_handler b prefetch_abort_handler b data_abort_handler b reserved_handler b irq_handler b fiq_handler /* * Function: code_copy * Variables: * r0 = from * r1 = to * r2 = length */ .section .init.text, "ax", %progbits .align 0x04 .global word_copy .type word_copy, %function word_copy: sub r2, r2, #0x04 cmp r2, #0 ldrge r3, [r0], #4 strge r3, [r1], #4 bgt word_copy bx lr .ltorg .size word_copy, .-word_copy /* * Entry: start * Variables: * none */ .section .init.text,"ax",%progbits .code 32 .align 0x04 /* Align */ .global start start: msr cpsr, #0xd3 /* enter supervisor mode, disable IRQ */ /* Disable the watchdog */ ldr r2, =0x00000000 mov r1, #0x53000000 str r2, [r1] /* Mask all Interupts to be safe */ ldr r2, =0xFFFFFFFF mov r1, #0x4A000000 str r2, [r1] /* Submask too */ ldr r2, =0x00003FFF str r2, [r1, #0x1C] /* Check if loaded by the old bootloader or by the OF * Be careful with code size above this as well. */ /* Get the execute address (cannot be past 0x100 for this to work */ ldr r0, =0xffffff00 and r0, pc, r0 /* Calculate the length of the code needed to run/copy */ ldr r1, = _vectorstart ldr r2, = _initdata_end sub r2, r2, r1 add r3, r2, #0x30000000 /* Is there enough space to copy without overwriting? */ cmp r0, r3 /* There's enough space, skip copying */ bgt skipreset /* Is this code running from 0x0? If so skip copy. */ cmplt r0, #0 beq skipreset /* There's not enough space to copy without overwriting, copy to safe spot * and reset */ mov r1, #0x31000000 /* copy location */ bl word_copy mov pc, #0x31000000 skipreset: /* Initial Clock Setup */ mov r2, #0x7 mov r1, #0x4C000000 str r2, [r1, #0x14] mov r2, #0x0 str r2, [r1, #0x18] ldr r2, =0xFFFFFFFF str r2, [r1] ldr r2, =0x0003C042 str r2, [r1, #0x08] nop nop nop nop nop nop nop nop ldr r2, =0x000C9042 str r2, [r1, #0x04] nop nop nop nop nop nop nop nop /* If we want to disable extraneous clocks, uncomment, but it can * freeze the device */ #if 0 ldr r2, =0x6030 mov r1, #0x4C000000 str r2, [r1, #0x0C] #endif /* set Bus to Asynchronous mode (full speed) */ mov r0, #0 mrc p15, 0, r0, c1, c0, 0 ldr r1, =0xC0000000 orr r0, r0, r1 mcr p15, 0, r0, c1, c0, 0 /* Setup MISCCR */ ldr r2, =0x00613020 mov r1, #0x56000000 str r2, [r1, #0x80] /* Setup some unknown outputs in GPB and GPH */ ldr r2, [r1, #0x10] mov r3, #0x05 orr r2, r3, r2 str r2, [r1, #0x10] ldr r2, [r1, #0x14] mov r3, #0x03 orr r2, r3, r2 str r2, [r1, #0x14] ldr r2, [r1, #0x70] mov r3, #0x05 orr r2, r3, r2 str r2, [r1, #0x70] ldr r2, [r1, #0x74] mov r3, #0x03 orr r2, r3, r2 str r2, [r1, #0x74] /* Memory setup (taken from 0x5070) */ /* BWSCON * Reserved 0 * Bank 0: * Bus width 01 (16 bit) * Bank 1: * Buswidth 00 (8 bit) * Disable wait 0 * Not using UB/LB 0 * Bank 2: * Buswidth 10 (32 bit) * Disable wait 0 * Not using UB/LB 0 * Bank 3: * Buswidth 10 (32 bit) * Disable wait 0 * Use UB/LB 1 * Bank 4: * Buswidth 10 (32 bit) * Disable wait 0 * Use UB/LB 1 * Bank 5: * Buswidth 00 (8 bit) * Disable wait 0 * Not using UB/LB 0 * Bank 6: * Buswidth 10 (32 bit) * Disable wait 0 * Not using UB/LB 0 * Bank 7: * Buswidth 00 (8 bit) * Disable wait 0 * Not using UB/LB 0 */ ldr r2, =0x01055102 mov r1, #0x48000000 str r2, [r1] /* BANKCON0 * Pagemode: normal (1 data) 00 * Pagemode access cycle: 2 clocks 00 * Address hold: 2 clocks 10 * Chip selection hold time: 1 clock 10 * Access cycle: 8 clocks 101 * Chip select setup time: 1 clock 01 * Address setup time: 0 clock 00 */ ldr r2, =0x00000D60 str r2, [r1, #0x04] /* BANKCON1 * Pagemode: normal (1 data) 00 * Pagemode access cycle: 2 clocks 00 * Address hold: 0 clocks 00 * Chip selection hold time: 0 clock 00 * Access cycle: 1 clocks 000 * Chip select setup time: 0 clocks 00 * Address setup time: 0 clocks 00 */ ldr r2, =0x00000000 str r2, [r1, #0x08] /* BANKCON2 * Pagemode: normal (1 data) 00 * Pagemode access cycle: 2 clocks 00 * Address hold: 2 clocks 10 * Chip selection hold time: 2 clocks 10 * Access cycle: 14 clocks 111 * Chip select setup time: 4 clocks 11 * Address setup time: 0 clocks 00 */ ldr r2, =0x00001FA0 str r2, [r1, #0xC] /* BANKCON3 */ ldr r2, =0x00001D80 str r2, [r1, #0x10] /* BANKCON4 */ str r2, [r1, #0x14] /* BANKCON5 */ ldr r2, =0x00000000 str r2, [r1, #0x18] /* BANKCON6/7 * SCAN: 9 bit 01 * Trcd: 3 clocks 01 * Tcah: 0 clock 00 * Tcoh: 0 clock 00 * Tacc: 1 clock 000 * Tcos: 0 clock 00 * Tacs: 0 clock 00 * MT: Sync DRAM 11 */ ldr r2, =0x00018005 str r2, [r1, #0x1C] /* BANKCON7 */ str r2, [r1, #0x20] /* REFRESH */ ldr r2, =0x00980501 str r2, [r1, #0x24] /* BANKSIZE * BK76MAP: 32M/32M 000 * Reserved: 0 0 (was 1) * SCLK_EN: always 1 (was 0) * SCKE_EN: disable 0 * Reserved: 0 0 * BURST_EN: enabled 1 */ ldr r2, =0x00000090 str r2, [r1, #0x28] /* MRSRB6 */ ldr r2, =0x00000030 str r2, [r1, #0x2C] /* MRSRB7 */ str r2, [r1, #0x30] #if 0 /* GPACON */ mov r1, #0x56000000 ldr r2, =0x01FFFCFF /* 0x01FFFCFF */ str r2, [r1] /* GPADAT */ ldr r2, =0x01FFFEFF str r2, [r1, #0x04] /* MRSRB6 */ mov r1, #0x48000000 mov r2, #0x00000000 str r2, [r1, #0x2C] /* GPADAT */ mov r1, #0x56000000 ldr r2, =0x01FFFFFF str r2, [r1, #0x04] /* MRSRB6 */ mov r1, #0x48000000 mov r2, #0x00000030 str r2, [r1, #0x2C] /* GPACON */ mov r1, #0x56000000 mov r2, #0x01FFFFFF str r2, [r1] /* End of the unknown */ #endif /* The builds have two potential load addresses, one being from flash, * and the other from some "unknown" location right now the assumption * is that the code is not at 0x3000000. */ /* get the high part of our execute address (where am I) */ ldr r0, =0xfffff000 and r0, pc, r0 /* Copy code to 0x30000000 */ ldr r2, = _vectorstart ldr r3, = _initdata_end sub r2, r3, r2 /* length of loader */ ldr r1, =0x30000000 /* copy location */ bl word_copy ldr r1, =donecopy ldr r2, =0x30000000 add r1, r1, r2 mov pc, r1 /* The code is located where we want it-jump*/ donecopy: /* Setup the MMU, start by disabling */ mrc p15, 0, r0, c1, c0, 0 bic r0, r0, #0x41 /* disable mmu and dcache */ bic r0, r0, #0x1000 /* disable icache */ mcr p15, 0, r0, c1, c0, 0 bl ttb_init ldr r0, =0x0 ldr r1, =0x0 ldr r2, =0x1000 mov r3, #0 bl map_section ldr r0, =0x30000000 ldr r1, =0x0 mov r2, #32 mov r3, #12 bl map_section ldr r0, =0x31FD6800 /* FRAME */ mov r1, r0 mov r2, #1 mov r3, #4 bl map_section bl enable_mmu /* Initialise bss section to zero */ ldr r2, =_edata ldr r3, =_end mov r4, #0 bsszero: cmp r3, r2 strhi r4, [r2], #4 bhi bsszero /* Set up some stack and munge it with 0xdeadbeef */ ldr sp, =stackend mov r3, sp ldr r2, =stackbegin ldr r4, =0xdeadbeef stackmunge: cmp r3, r2 strhi r4, [r2], #4 bhi stackmunge /* Set up stack for IRQ mode */ msr cpsr_c, #0xd2 ldr sp, =irq_stack /* Set up stack for FIQ mode */ msr cpsr_c, #0xd1 ldr sp, =fiq_stack /* Let abort and undefined modes use IRQ stack */ msr cpsr_c, #0xd7 ldr sp, =irq_stack msr cpsr_c, #0xdb ldr sp, =irq_stack /* Switch to supervisor mode */ msr cpsr_c, #0xd3 ldr sp, =stackend /* Start the main function */ ldr pc, =main /* Should never get here, but let's restart in case */ // b vectors /* All illegal exceptions call into UIE with exception address as first parameter. This is calculated differently depending on which exception we're in. Second parameter is exception number, used for a string lookup in UIE. */ undef_instr_handler: mov r0, lr mov r1, #0 b UIE /* We run supervisor mode most of the time, and should never see a software exception being thrown. Perhaps make it illegal and call UIE? */ software_int_handler: reserved_handler: movs pc, lr prefetch_abort_handler: sub r0, lr, #4 mov r1, #1 b UIE data_abort_handler: sub r0, lr, #8 mov r1, #2 b UIE #if defined(BOOTLOADER) fiq_handler: b UIE #endif UIE: b UIE .section .text /* 256 words of IRQ stack */ .space 256*4 irq_stack: /* 256 words of FIQ stack */ .space 256*4 fiq_stack: