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+/* 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
+
+/*
+ * Note: _armboot_end_data and _armboot_end are defined
+ * by the (board-dependent) linker script.
+ * _armboot_end_data is the first usable FLASH address after armboot
+ */
+.globl _armboot_end_data
+_armboot_end_data:
+ .word armboot_end_data
+.globl _armboot_end
+_armboot_end:
+ .word armboot_end
+
+/*
+ * This is defined in the board specific linker script
+ */
+.globl _bss_start
+_bss_start:
+ .word bss_start
+
+.globl _bss_end
+_bss_end:
+ .word bss_end
+
+/*
+ * _armboot_real_end is the first usable RAM address behind armboot
+ * and the various stacks
+ */
+.globl _armboot_real_end
+_armboot_real_end:
+ .word 0x0badc0de
+
+/*
+ * We relocate uboot to this address (end of RAM - 128 KiB)
+ */
+.globl _uboot_reloc
+_uboot_reloc:
+ .word TEXT_BASE
+
+#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 */
+ ldr r2, =IXP425_EXP_CFG0
+ ldr r1, [r2]
+ orr r1, r1, #0x80000000
+ str r1, [r2]
+
+ 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, #1
+ 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
+
+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, _armboot_end
+ 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
+
+ /* Set up the stack */
+
+stack_setup:
+
+ ldr r0, _uboot_reloc /* upper 128 KiB: relocated uboot */
+ sub r0, r0, #CFG_MALLOC_LEN /* malloc area */
+ /* FIXME: bdinfo should be here */
+ sub sp, r0, #12 /* leave 3 words for abort-stack */
+
+clear_bss:
+
+ ldr r0, _bss_start /* find start of bss segment */
+ add r0, r0, #4 /* start at first byte of bss */
+ ldr r1, _bss_end /* stop here */
+ mov r2, #0x00000000 /* clear */
+
+clbss_l:str r2, [r0] /* clear loop... */
+ add r0, r0, #4
+ cmp r0, r1
+ bne 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_end
+ add r2, r2, #CONFIG_STACKSIZE
+ sub r2, r2, #8
+ 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_end @ setup our mode stack
+ add r13, r13, #CONFIG_STACKSIZE @ resides at top of normal stack
+ sub r13, r13, #8
+
+ 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