summaryrefslogtreecommitdiff
path: root/cpu/pxa/start.S
diff options
context:
space:
mode:
Diffstat (limited to 'cpu/pxa/start.S')
-rw-r--r--cpu/pxa/start.S474
1 files changed, 474 insertions, 0 deletions
diff --git a/cpu/pxa/start.S b/cpu/pxa/start.S
new file mode 100644
index 0000000..95b30e4
--- /dev/null
+++ b/cpu/pxa/start.S
@@ -0,0 +1,474 @@
+/*
+ * armboot - Startup Code for XScale
+ *
+ * Copyright (C) 1998 Dan Malek <dmalek@jlc.net>
+ * Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
+ * Copyright (C) 2000 Wolfgang Denk <wd@denx.de>
+ * Copyright (C) 2001 Alex Züpke <azu@sysgo.de>
+ * Copyright (C) 2002 Kyle Harris <kharris@nexus-tech.net>
+ * Copyright (C) 2003 Robert Schwebel <r.schwebel@pengutronix.de>
+ * Copyright (C) 2003 Kai-Uwe Bloehm <kai-uwe.bloem@auerswald.de>
+ *
+ * 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>
+
+.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
+ */
+
+/*
+ * CFG_MEM_END is in the board dependent config-file (configs/config_BOARD.h)
+ */
+_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:
+ mrs r0,cpsr /* set the cpu to SVC32 mode */
+ bic r0,r0,#0x1f /* (superviser mode, M=10011) */
+ orr r0,r0,#0x13
+ msr cpsr,r0
+
+ bl cpu_init_crit /* we do sys-critical inits */
+
+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
+
+
+/****************************************************************************/
+/* */
+/* CPU_init_critical registers */
+/* */
+/* - setup important registers */
+/* - setup memory timing */
+/* */
+/****************************************************************************/
+
+/* Interrupt-Controller base address */
+IC_BASE: .word 0x40d00000
+#define ICMR 0x04
+
+/* Reset-Controller */
+RST_BASE: .word 0x40f00030
+#define RCSR 0x00
+
+/* Operating System Timer */
+OSTIMER_BASE: .word 0x40a00000
+#define OSMR3 0x0C
+#define OSCR 0x10
+#define OWER 0x18
+#define OIER 0x1C
+
+/* Clock Manager Registers */
+CC_BASE: .word 0x41300000
+#define CCCR 0x00
+cpuspeed: .word CFG_CPUSPEED
+
+
+ /* RS: ??? */
+ .macro CPWAIT
+ mrc p15,0,r0,c2,c0,0
+ mov r0,r0
+ sub pc,pc,#4
+ .endm
+
+
+cpu_init_crit:
+
+ /* mask all IRQs */
+ ldr r0, IC_BASE
+ mov r1, #0x00
+ str r1, [r0, #ICMR]
+
+#if defined(CFG_CPUSPEED)
+
+ /* set clock speed */
+ ldr r0, CC_BASE
+ ldr r1, cpuspeed
+ str r1, [r0, #CCCR]
+ mov r0, #2
+ mcr p14, 0, r0, c6, c0, 0
+
+setspeed_done:
+#endif
+
+ /*
+ * before relocating, we have to setup RAM timing
+ * because memory timing is board-dependend, you will
+ * find a memsetup.S in your board directory.
+ */
+ mov ip, lr
+ bl memsetup
+ mov lr, ip
+
+ /* Memory interfaces are working. Disable MMU and enable I-cache. */
+
+ ldr r0, =0x2001 /* enable access to all coproc. */
+ mcr p15, 0, r0, c15, c1, 0
+ CPWAIT
+
+ mcr p15, 0, r0, c7, c10, 4 /* drain the write & fill buffers */
+ CPWAIT
+
+ mcr p15, 0, r0, c7, c7, 0 /* flush Icache, Dcache and BTB */
+ CPWAIT
+
+ mcr p15, 0, r0, c8, c7, 0 /* flush instuction and data TLBs */
+ CPWAIT
+
+ /* Enable the Icache */
+/*
+ mrc p15, 0, r0, c1, c0, 0
+ orr r0, r0, #0x1800
+ mcr p15, 0, r0, c1, c0, 0
+ CPWAIT
+*/
+ mov pc, lr
+
+
+/****************************************************************************/
+/* */
+/* 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: the PXA250 doesn't have a reset function, so we have to */
+/* perform a watchdog timeout for a soft reset. */
+/* */
+/****************************************************************************/
+
+ .align 5
+.globl reset_cpu
+
+ /* FIXME: this code is PXA250 specific. How is this handled on */
+ /* other XScale processors? */
+
+reset_cpu:
+
+ /* We set OWE:WME (watchdog enable) and wait until timeout happens */
+
+ ldr r0, OSTIMER_BASE
+ ldr r1, [r0, #OWER]
+ orr r1, r1, #0x0001 /* bit0: WME */
+ str r1, [r0, #OWER]
+
+ /* OS timer does only wrap every 1165 seconds, so we have to set */
+ /* the match register as well. */
+
+ ldr r1, [r0, #OSCR] /* read OS timer */
+ add r1, r1, #0x800 /* let OSMR3 match after */
+ add r1, r1, #0x800 /* 4096*(1/3.6864MHz)=1ms */
+ str r1, [r0, #OSMR3]
+
+reset_endless:
+
+ b reset_endless
+
generated by cgit v1.1 at 2024-11-23 22:20:23 +0000