sys/arch/rs6000/stand/boot/srt0.s

   1 /*      $NetBSD: srt0.s,v 1.3 2005/12/11 12:18:48 christos Exp $        */
   2
   3 /*
   4  * Copyright (C) 1996-1999 Cort Dougan (cort@fsmlasb.com).
   5  * Copyright (C) 1996-1999 Gary Thomas (gdt@osf.org).
   6  * Copyright (C) 1996-1999 Paul Mackeras (paulus@linuxcare.com).
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed by TooLs GmbH.
  20  * 4. The name of TooLs GmbH may not be used to endorse or promote products
  21  *    derived from this software without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
  24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  26  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  27  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  28  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  29  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  30  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  31  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  32  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33  */
  34
  35 #define MSR_IP          (1<<6)
  36
  37 #define HID0_DCI        (1<<10)
  38 #define HID0_ICFI       (1<<11)
  39 #define HID0_DCE        (1<<14)
  40 #define HID0_ICE        (1<<15)
  41
  42 /* when we start, the IPLCB pointer is in r3, and the extended one is in r4 */
  43
  44         .text
  45
  46         .globl  _start
  47 _start:
  48         bl      start
  49 start:
  50         mr      11,3            /* save the IPLCB pointer in r11 */
  51         mr      12,4            /* save the extended IPLCB in r12 */
  52         li      3,MSR_IP        /* Establish default MSR value */
  53         mtmsr   3
  54         isync
  55
  56         mflr    7
  57         bl      flush_icache
  58         mfspr   3,1008
  59         lis     4,~(HID0_ICE|HID0_DCE)@h
  60         ori     4,4,~(HID0_ICE|HID0_DCE)@l
  61         andc    3,3,4
  62         mtspr   1008,3
  63         mtlr    7
  64
  65 /* We aren't passed our loadaddr, so leave it alone */
  66 #if 0
  67 /*
  68  * check if we need to relocate ourselves to the link addr or were we
  69  * loaded there to begin with -- Cort
  70  */
  71         lis     4,_start@h
  72         ori     4,4,_start@l
  73         mflr    3
  74         subi    3,3,4           /* we get the nip, not the ip of the branch */
  75         mr      8,3
  76         cmpw    3,4
  77         bne     relocate
  78         b       start_ldr
  79
  80 /*
  81  * no matter where we're loaded, move ourselves to -Ttext address
  82  */
  83 relocate:
  84         lis     4,_start@h
  85         ori     4,4,_start@l
  86         lis     5,end@h
  87         ori     5,5,end@l
  88         addi    5,5,3           /* Round up - just in case */
  89         sub     5,5,4           /* Compute # longwords to move */
  90         srwi    5,5,2
  91         mtctr   5
  92         subi    3,3,4           /* Set up for loop */
  93         subi    4,4,4
  94 2:
  95         lwzu    5,4(3)
  96         stwu    5,4(4)
  97         bdnz    2b
  98         lis     3,start_ldr@h
  99         ori     3,3,start_ldr@l
 100         mtlr    3               /* Easiest way to do an absolute jump */
 101         blr
 102 #endif
 103
 104 start_ldr:
 105         mr      9,1             /* Save old stack pointer */
 106         lis     1,.stack@h
 107         ori     1,1,.stack@l
 108         addi    1,1,4096
 109         li      2,0x000F
 110         andc    1,1,2
 111         mr      3,11            /* arg1: IPLCB pointer */
 112         mr      4,12            /* arg2: IPLCB extended block pointer */
 113         bl      boot
 114 hang:
 115         b       hang
 116
 117 /*
 118  * Execute
 119  * run(startsym, endsym, args, bootinfo, entry)
 120  */
 121         .globl  run
 122 run:
 123         mtctr   7                       /* Entry point */
 124         bctr
 125
 126 /*
 127  * Flush instruction cache
 128  */
 129         .globl flush_icache
 130 flush_icache:
 131         mflr    5
 132         bl      flush_dcache
 133         mfspr   4,1008
 134         li      4,0
 135         ori     4,4,HID0_ICE|HID0_ICFI
 136         or      3,3,4
 137         mtspr   1008,3
 138         andc    3,3,4
 139         ori     3,3,HID0_ICE
 140         mtspr   1008,3
 141         mtlr    5
 142         blr
 143
 144 /*
 145  * Flush data cache
 146  */
 147         .globl flush_dcache
 148 flush_dcache:
 149         lis     3,0x1000@h
 150         ori     3,3,0x1000@l
 151         li      4,1024
 152         mtctr   4
 153 1:
 154         lwz     4,0(3)
 155         addi    3,3,32
 156         bdnz    1b
 157         blr
 158
 159 #if 0
 160 /*
 161  * write LEDS
 162  */
 163
 164         .globl led
 165 led:
 166         mfmsr   5       /* save MSR to r5 */
 167         lis     7,0xffff
 168         ori     7,7,~(MSR_DR)
 169         and     6,5,7
 170         mtmsr   6
 171         isync
 172
 173 #endif
 174 /*
 175  * local stack
 176  */
 177         .comm   .stack,8192,4