PXA: Rework start.S to be closer to other ARMs
The start.S on PXA was very obscure. This reworks it back to be close to arm1136
start.S and others.
Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
V2: Don't compile in relocation support if building SPL
diff --git a/arch/arm/cpu/pxa/start.S b/arch/arm/cpu/pxa/start.S
index 6191a73..88a4cc2 100644
--- a/arch/arm/cpu/pxa/start.S
+++ b/arch/arm/cpu/pxa/start.S
@@ -1,14 +1,20 @@
/*
- * armboot - Startup Code for XScale
+ * armboot - Startup Code for XScale CPU-core
*
* 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 Zuepke <azu@sysgo.de>
+ * Copyright (C) 2001 Marius Groger <mag@sysgo.de>
+ * Copyright (C) 2002 Alex Zupke <azu@sysgo.de>
+ * Copyright (C) 2002 Gary Jennejohn <garyj@denx.de>
* Copyright (C) 2002 Kyle Harris <kharris@nexus-tech.net>
- * Copyright (C) 2003 Robert Schwebel <r.schwebel@pengutronix.de>
* Copyright (C) 2003 Kai-Uwe Bloem <kai-uwe.bloem@auerswald.de>
- * Copyright (c) 2010 Marek Vasut <marek.vasut@gmail.com>
+ * Copyright (C) 2003 Kshitij <kshitij@ti.com>
+ * Copyright (C) 2003 Richard Woodruff <r-woodruff2@ti.com>
+ * Copyright (C) 2003 Robert Schwebel <r.schwebel@pengutronix.de>
+ * Copyright (C) 2004 Texas Instruments <r-woodruff2@ti.com>
+ * Copyright (C) 2010 Marek Vasut <marek.vasut@gmail.com>
*
* See file CREDITS for list of people who contributed to this
* project.
@@ -32,15 +38,6 @@
#include <asm-offsets.h>
#include <config.h>
#include <version.h>
-#include <asm/arch/pxa-regs.h>
-
-/* takes care the CP15 update has taken place */
-.macro CPWAIT reg
-mrc p15,0,\reg,c2,c0,0
-mov \reg,\reg
-sub pc,pc,#4
-.endm
-
.globl _start
_start: b reset
#ifdef CONFIG_SPL_BUILD
@@ -77,26 +74,38 @@
_not_used: .word not_used
_irq: .word irq
_fiq: .word fiq
+_pad: .word 0x12345678 /* now 16*4=64 */
#endif /* CONFIG_SPL_BUILD */
+.global _end_vect
+_end_vect:
.balignl 16,0xdeadbeef
-
-
/*
+ *************************************************************************
+ *
* Startup Code (reset vector)
*
- * do important init only if we don't start from RAM!
- * - relocate armboot to RAM
- * - setup stack
- * - jump to second stage
+ * do important init only if we don't start from memory!
+ * setup Memory and board specific bits prior to relocation.
+ * relocate armboot to ram
+ * setup stack
+ *
+ *************************************************************************
*/
.globl _TEXT_BASE
_TEXT_BASE:
+#ifdef CONFIG_SPL_BUILD
+ .word CONFIG_SPL_TEXT_BASE
+#else
.word CONFIG_SYS_TEXT_BASE
+#endif
/*
* These are defined in the board-specific linker script.
+ * Subtracting _start from them lets the linker put their
+ * relative position in the executable instead of leaving
+ * them null.
*/
.globl _bss_start_ofs
_bss_start_ofs:
@@ -120,9 +129,8 @@
.globl FIQ_STACK_START
FIQ_STACK_START:
.word 0x0badc0de
-#endif /* CONFIG_USE_IRQ */
+#endif
-#ifndef CONFIG_SPL_BUILD
/* IRQ stack memory (calculated at run-time) + 8 bytes */
.globl IRQ_STACK_START_IN
IRQ_STACK_START_IN:
@@ -141,95 +149,19 @@
orr r0,r0,#0xd3
msr cpsr,r0
- /*
- * Enable MMU to use DCache as DRAM
- */
- /* Domain access -- enable for all CPs */
- ldr r0, =0x0000ffff
- mcr p15, 0, r0, c3, c0, 0
-
- /* Point TTBR to MMU table */
- ldr r0, =mmu_table
- adr r2, _start
- orr r0, r2
- mcr p15, 0, r0, c2, c0, 0
-
-/* !!! Hereby, check if the code is running from SRAM !!! */
-/* If the code is running from SRAM, alias SRAM to 0x0 to simulate NOR. The code
- * is linked to 0x0 too, so this makes things easier. */
- cmp r2, #0x5c000000
-
- ldreq r1, [r0]
- orreq r1, r2
- streq r1, [r0]
-
- /* Kick in MMU, ICache, DCache, BTB */
- mrc p15, 0, r0, c1, c0, 0
- bic r0, #0x1b00
- bic r0, #0x0087
- orr r0, #0x1800
- orr r0, #0x0005
- mcr p15, 0, r0, c1, c0, 0
- CPWAIT r0
-
- /* Unlock Icache, Dcache */
- mcr p15, 0, r0, c9, c1, 1
- mcr p15, 0, r0, c9, c2, 1
-
- /* Flush Icache, Dcache, BTB */
- mcr p15, 0, r0, c7, c7, 0
-
- /* Unlock I-TLB, D-TLB */
- mcr p15, 0, r0, c10, c4, 1
- mcr p15, 0, r0, c10, c8, 1
-
- /* Flush TLB */
- mcr p15, 0, r0, c8, c7, 0
- /* Allocate 4096 bytes of Dcache as RAM */
-
- /* Drain pending loads and stores */
- mcr p15, 0, r0, c7, c10, 4
-
- mov r4, #0x00
- mov r5, #0x00
- mov r2, #0x01
- mcr p15, 0, r0, c9, c2, 0
- CPWAIT r0
-
- /* 128 lines reserved (128 x 32bytes = 4096 bytes total) */
- mov r0, #128
- mov r1, #0xa0000000
-alloc:
- mcr p15, 0, r1, c7, c2, 5
- /* Drain pending loads and stores */
- mcr p15, 0, r0, c7, c10, 4
- strd r4, [r1], #8
- strd r4, [r1], #8
- strd r4, [r1], #8
- strd r4, [r1], #8
- subs r0, #0x01
- bne alloc
- /* Drain pending loads and stores */
- mcr p15, 0, r0, c7, c10, 4
- mov r2, #0x00
- mcr p15, 0, r2, c9, c2, 0
- CPWAIT r0
-
- /* Jump to 0x0 ( + offset) if running from SRAM */
- adr r0, zerojmp
- bic r0, #0x5c000000
- mov pc, r0
-zerojmp:
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT
+ bl cpu_init_crit
+#endif
/* Set stackpointer in internal RAM to call board_init_f */
call_board_init_f:
ldr sp, =(CONFIG_SYS_INIT_SP_ADDR)
bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
- ldr r0,=0x00000000
+ ldr r0, =0x00000000
bl board_init_f
/*------------------------------------------------------------------------------*/
-
+#ifndef CONFIG_SPL_BUILD
/*
* void relocate_code (addr_sp, gd, addr_moni)
*
@@ -254,13 +186,11 @@
ldr r3, _bss_start_ofs
add r2, r0, r3 /* r2 <- source end address */
- stmfd sp!, {r0-r12}
copy_loop:
- ldmia r0!, {r3-r5, r7-r11} /* copy from source address [r0] */
- stmia r1!, {r3-r5, r7-r11} /* copy to target address [r1] */
+ ldmia r0!, {r9-r10} /* copy from source address [r0] */
+ stmia r1!, {r9-r10} /* copy to target address [r1] */
cmp r0, r2 /* until source end address [r2] */
blo copy_loop
- ldmfd sp!, {r0-r12}
#ifndef CONFIG_SPL_BUILD
/*
@@ -275,13 +205,13 @@
ldr r3, _rel_dyn_end_ofs /* r3 <- rel dyn end ofs */
add r3, r3, r0 /* r3 <- rel dyn end in FLASH */
fixloop:
- ldr r0, [r2] /* r0 <- location to fix up, IN FLASH! */
- add r0, r9 /* r0 <- location to fix up in RAM */
+ ldr r0, [r2] /* r0 <- location to fix up, IN FLASH! */
+ add r0, r0, r9 /* r0 <- location to fix up in RAM */
ldr r1, [r2, #4]
and r7, r1, #0xff
- cmp r7, #23 /* relative fixup? */
+ cmp r7, #23 /* relative fixup? */
beq fixrel
- cmp r7, #2 /* absolute fixup? */
+ cmp r7, #2 /* absolute fixup? */
beq fixabs
/* ignore unknown type of fixup */
b fixnext
@@ -298,10 +228,10 @@
add r1, r1, r9
fixnext:
str r1, [r0]
- add r2, r2, #8 /* each rel.dyn entry is 8 bytes */
+ add r2, r2, #8 /* each rel.dyn entry is 8 bytes */
cmp r2, r3
blo fixloop
-#endif /* #ifndef CONFIG_SPL_BUILD */
+#endif
clear_bss:
#ifndef CONFIG_SPL_BUILD
@@ -322,15 +252,16 @@
* We are done. Do not return, instead branch to second part of board
* initialization, now running from RAM.
*/
-#ifdef CONFIG_ONENAND_IPL
- ldr r0, _start_oneboot_ofs
+#ifdef CONFIG_ONENAND_SPL
+ ldr r0, _onenand_boot_ofs
mov pc, r0
-_start_oneboot_ofs
- : .word start_oneboot
+_onenand_boot_ofs:
+ .word onenand_boot
#else
+jump_2_ram:
ldr r0, _board_init_r_ofs
- adr r1, _start
+ ldr r1, _TEXT_BASE
add lr, r0, r1
add lr, lr, r9
/* setup parameters for board_init_r */
@@ -341,7 +272,7 @@
_board_init_r_ofs:
.word board_init_r - _start
-#endif /* CONFIG_ONENAND_IPL */
+#endif
_rel_dyn_start_ofs:
.word __rel_dyn_start - _start
@@ -349,43 +280,50 @@
.word __rel_dyn_end - _start
_dynsym_start_ofs:
.word __dynsym_start - _start
-
-#else /* CONFIG_SPL_BUILD */
-
-/****************************************************************************/
-/* */
-/* the actual reset code for OneNAND IPL */
-/* */
-/****************************************************************************/
-
-#ifndef CONFIG_PXA27X
-#error OneNAND IPL is not supported on PXA25x and 26x due to lack of SRAM
#endif
+/*
+ *************************************************************************
+ *
+ * CPU_init_critical registers
+ *
+ * setup important registers
+ * setup memory timing
+ *
+ *************************************************************************
+ */
+#ifndef CONFIG_SKIP_LOWLEVEL_INIT
+cpu_init_crit:
+ /*
+ * flush v4 I/D caches
+ */
+ mov r0, #0
+ mcr p15, 0, r0, c7, c7, 0 /* Invalidate I+D+BTB caches */
+ mcr p15, 0, r0, c8, c7, 0 /* Invalidate Unified TLB */
-reset:
- /* Set CPU to SVC32 mode */
- mrs r0,cpsr
- bic r0,r0,#0x1f
- orr r0,r0,#0x13
- msr cpsr,r0
+ /*
+ * disable MMU stuff and caches
+ */
+ mrc p15, 0, r0, c1, c0, 0
+ bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
+ bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
+ orr r0, r0, #0x00000002 @ set bit 2 (A) Align
+ orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
+ mcr p15, 0, r0, c1, c0, 0
- /* Point stack at the end of SRAM and leave 32 words for abort-stack */
- ldr sp, =0x5c03ff80
-
- /* Start OneNAND IPL */
- ldr pc, =start_oneboot
-
-#endif /* CONFIG_SPL_BUILD */
+ mov pc, lr /* back to my caller */
+#endif /* CONFIG_SKIP_LOWLEVEL_INIT */
#ifndef CONFIG_SPL_BUILD
-/****************************************************************************/
-/* */
-/* Interrupt handling */
-/* */
-/****************************************************************************/
-
-/* IRQ stack frame */
-
+/*
+ *************************************************************************
+ *
+ * Interrupt handling
+ *
+ *************************************************************************
+ */
+@
+@ IRQ stack frame.
+@
#define S_FRAME_SIZE 72
#define S_OLD_R0 68
@@ -409,37 +347,36 @@
#define S_R0 0
#define MODE_SVC 0x13
+#define I_BIT 0x80
- /* use bad_save_user_regs for abort/prefetch/undef/swi ... */
+/*
+ * use bad_save_user_regs for abort/prefetch/undef/swi ...
+ * use irq_save_user_regs / irq_restore_user_regs for IRQ/FIQ handling
+ */
.macro bad_save_user_regs
- sub sp, sp, #S_FRAME_SIZE
- stmia sp, {r0 - r12} /* Calling r0-r12 */
- add r8, sp, #S_PC
+ sub sp, sp, #S_FRAME_SIZE @ carve out a frame on current user stack
+ stmia sp, {r0 - r12} @ Save user registers (now in svc mode) r0-r12
- ldr r2, IRQ_STACK_START_IN
- ldmia r2, {r2 - r4} /* get pc, cpsr, old_r0 */
- add r0, sp, #S_FRAME_SIZE /* restore sp_SVC */
+ ldr r2, IRQ_STACK_START_IN @ set base 2 words into abort stack
+ ldmia r2, {r2 - r3} @ get values for "aborted" pc and cpsr (into parm regs)
+ add r0, sp, #S_FRAME_SIZE @ grab pointer to old stack
add r5, sp, #S_SP
mov r1, lr
- stmia r5, {r0 - r4} /* save sp_SVC, lr_SVC, pc, cpsr, old_r */
- mov r0, sp
+ stmia r5, {r0 - r3} @ save sp_SVC, lr_SVC, pc, cpsr
+ mov r0, sp @ save current stack into r0 (param register)
.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 */
+ stmia sp, {r0 - r12} @ Calling r0-r12
+ add r8, sp, #S_PC @ !!!! R8 NEEDS to be saved !!!! a reserved stack spot would be good.
+ 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 */
+ str r6, [r8, #4] @ Save CPSR
+ str r0, [r8, #8] @ Save OLD_R0
mov r0, sp
.endm
@@ -452,16 +389,28 @@
.endm
.macro get_bad_stack
- ldr r13, IRQ_STACK_START_IN @ setup our mode stack
+ ldr r13, IRQ_STACK_START_IN @ setup our mode stack (enter in banked mode)
- str lr, [r13] @ save caller lr / spsr
- mrs lr, spsr
- str lr, [r13, #4]
+ str lr, [r13] @ save caller lr in position 0 of saved stack
+ mrs lr, spsr @ get the spsr
+ str lr, [r13, #4] @ save spsr in position 1 of saved stack
mov r13, #MODE_SVC @ prepare SVC-Mode
- msr spsr_c, r13
- mov lr, pc
- movs pc, lr
+ @ msr spsr_c, r13
+ msr spsr, r13 @ switch modes, make sure moves will execute
+ mov lr, pc @ capture return pc
+ movs pc, lr @ jump to next instruction & switch modes.
+ .endm
+
+ .macro get_bad_stack_swi
+ sub r13, r13, #4 @ space on current stack for scratch reg.
+ str r0, [r13] @ save R0's value.
+ ldr r0, IRQ_STACK_START_IN @ get data regions start
+ str lr, [r0] @ save caller lr in position 0 of saved stack
+ mrs r0, spsr @ get the spsr
+ str lr, [r0, #4] @ save spsr in position 1 of saved stack
+ ldr r0, [r13] @ restore r0
+ add r13, r13, #4 @ pop stack entry
.endm
.macro get_irq_stack @ setup IRQ stack
@@ -471,21 +420,17 @@
.macro get_fiq_stack @ setup FIQ stack
ldr sp, FIQ_STACK_START
.endm
-#endif /* CONFIG_SPL_BUILD
+#endif /* CONFIG_SPL_BUILD */
-
-/****************************************************************************/
-/* */
-/* exception handlers */
-/* */
-/****************************************************************************/
-
+/*
+ * exception handlers
+ */
#ifdef CONFIG_SPL_BUILD
.align 5
do_hang:
- ldr sp, _TEXT_BASE /* use 32 words abort stack */
+ ldr sp, _TEXT_BASE /* use 32 words about stack */
bl hang /* hang and never return */
-#else
+#else /* !CONFIG_SPL_BUILD */
.align 5
undefined_instruction:
get_bad_stack
@@ -494,7 +439,7 @@
.align 5
software_interrupt:
- get_bad_stack
+ get_bad_stack_swi
bad_save_user_regs
bl do_software_interrupt
@@ -528,11 +473,12 @@
.align 5
fiq:
get_fiq_stack
- irq_save_user_regs /* someone ought to write a more */
- bl do_fiq /* effiction fiq_save_user_regs */
+ /* someone ought to write a more effiction fiq_save_user_regs */
+ irq_save_user_regs
+ bl do_fiq
irq_restore_user_regs
-#else /* !CONFIG_USE_IRQ */
+#else
.align 5
irq:
@@ -545,63 +491,7 @@
get_bad_stack
bad_save_user_regs
bl do_fiq
-#endif /* CONFIG_SPL_BUILD */
-#endif /* CONFIG_USE_IRQ */
-/****************************************************************************/
-/* */
-/* Reset function: the PXA250 doesn't have a reset function, so we have to */
-/* perform a watchdog timeout for a soft reset. */
-/* */
-/****************************************************************************/
-/* Operating System Timer */
-.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, =OWER
- ldr r1, [r0]
- orr r1, r1, #0x0001 /* bit0: WME */
- str r1, [r0]
-
- /* OS timer does only wrap every 1165 seconds, so we have to set */
- /* the match register as well. */
-
- ldr r0, =OSCR
- ldr r1, [r0] /* read OS timer */
- add r1, r1, #0x800 /* let OSMR3 match after */
- add r1, r1, #0x800 /* 4096*(1/3.6864MHz)=1ms */
- ldr r0, =OSMR3
- str r1, [r0]
-
-reset_endless:
-
- b reset_endless
-
-#ifndef CONFIG_SPL_BUILD
-.section .mmudata, "a"
- .align 14
- .globl mmu_table
-mmu_table:
- /* 0x00000000 - 0xa0000000 : 1:1, uncached mapping */
- .set __base, 0
- .rept 0xa00
- .word (__base << 20) | 0xc12
- .set __base, __base + 1
- .endr
-
- /* 0xa0000000 - 0xa0100000 : 1:1, cached mapping */
- .word (0xa00 << 20) | 0x1c1e
-
- .set __base, 0xa01
- .rept 0x1000 - 0xa01
- .word (__base << 20) | 0xc12
- .set __base, __base + 1
- .endr
+#endif
+ .align 5
#endif /* CONFIG_SPL_BUILD */