1/* $NetBSD: viper_start.S,v 1.6 2011/01/31 06:28:06 matt Exp $ */ 2 3/* 4 * Copyright (c) 2005 Antti Kantee. All Rights Reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the company nor the name of the author may be used to 15 * endorse or promote products derived from this software without specific 16 * prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 19 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 21 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 24 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31#include <machine/asm.h> 32#include <arm/armreg.h> 33#include "assym.h" 34 35RCSID("$NetBSD: viper_start.S,v 1.6 2011/01/31 06:28:06 matt Exp $") 36 37/* 38 * We start out with RAM mapped to the bottom 64MB. We are jogging 39 * happily there with the MMU on. Our mission: map some important 40 * bootstrap devices (such as console port) in addition to mapping 41 * the physical RAM to 0xc0... 42 * 43 * If I try to create a mapping from scratch, something important gets 44 * wiped out (never could figure out exactly what), so we do this with 45 * the MMU on adding to the existing translation table. 46 */ 47 48#define CPWAIT_BRANCH \ 49 sub pc, pc, #4 50 51#define CPWAIT(tmp) \ 52 mrc p15, 0, tmp, c2, c0, 0 /* arbitrary read of CP15 */ ;\ 53 mov tmp, tmp /* wait for it to complete */ ;\ 54 CPWAIT_BRANCH /* branch to next insn */ 55 56#ifndef SDRAM_START 57#define SDRAM_START 0xa0000000 58#endif 59#define XSCALE_DCACHE_SIZE 0x8000 60 61 .text 62 63 .global _C_LABEL(viper_start) 64_C_LABEL(viper_start): 65 66 /* Figure out where we want to jump to when the time comes */ 67 adr r8, .Linva 68 ldr r8, [r8] 69 70 /* 71 * Start playing with the virtual address space mapping 72 * for initial bootstrap. 73 * 74 * Load registers, which will remain constant throughout 75 * building the VA mapping. 76 */ 77 mov r2, #(L1_S_SIZE) /* 1MB chunks */ 78 79 /* 80 * First map SDRAM VA == PA. This enables us to cut&waste 81 * some existing initarm() code without modification 82 * (and, if, god forbid, someone would like to unify them 83 * some day, this'll make that job easier) 84 */ 85 mrc p15, 0, r0, c2, c0, 0 /* Get L1 */ 86 bic r0, r0, #0xff000000 87 add r0, r0, #(0xa00 * 4) /* offset to 0xa0.. */ 88 89 mov r3, #SDRAM_START /* map to 0xa00.. */ 90 orr r3, r3, #(L1_S_AP_KRW) /* the usual perms & stuff */ 91 orr r3, r3, #(L1_TYPE_S) 92 orr r3, r3, #(L1_S_DOM_KERNEL) 93 mov r1, #0x40 /* 64 1MB entries */ 94 951: 96 /* and looplooploop */ 97 str r3, [r0], #4 98 add r3, r3, r2 99 subs r1, r1, #1 100 bgt 1b 101 102 /* 103 * Map SDRAM also to VA 0xc00... 104 */ 105 mrc p15, 0, r0, c2, c0, 0 /* Get L1 */ 106 bic r0, r0, #0xff000000 107 add r0, r0, #(0xc00 * 4) /* start from 0xc00.. */ 108 109 mov r3, #SDRAM_START /* map to 0xa00.. */ 110 orr r3, r3, #(L1_S_AP_KRW) /* the usual perms & stuff */ 111 orr r3, r3, #(L1_TYPE_S) 112 orr r3, r3, #(L1_S_DOM_KERNEL) 113 mov r1, #0x40 /* 64 1MB entries */ 114 1151: 116 /* and looplooploop */ 117 str r3, [r0], #4 118 add r3, r3, r2 119 subs r1, r1, #1 120 bgt 1b 121 122 /* 123 * Here come the devices. Map an L1 section for each device 124 * to make this easy. 125 */ 126 127 /* INTCTL */ 128 mrc p15, 0, r0, c2, c0, 0 /* Get L1 */ 129 bic r0, r0, #0xff000000 130 add r0, r0, #(0xfd0 * 4) /* offset to 0xfd000000 */ 131 132 mov r3, #0x40000000 133 orr r3, r3, #0x00d00000 134 orr r3, r3, #(L1_S_AP_KRW) 135 orr r3, r3, #(L1_TYPE_S) 136 orr r3, r3, #(L1_S_DOM_KERNEL) 137 str r3, [r0], #4 138 139 /* GPIO */ 140 mov r3, #0x40000000 141 orr r3, r3, #0x00e00000 142 orr r3, r3, #(L1_S_AP_KRW) 143 orr r3, r3, #(L1_TYPE_S) 144 orr r3, r3, #(L1_S_DOM_KERNEL) 145 str r3, [r0], #4 146 147 /* CLKMAN */ 148 mov r3, #0x41000000 149 orr r3, r3, #0x00300000 150 orr r3, r3, #(L1_S_AP_KRW) 151 orr r3, r3, #(L1_TYPE_S) 152 orr r3, r3, #(L1_S_DOM_KERNEL) 153 str r3, [r0], #4 154 155 /* FFUART */ 156 mov r3, #0x40000000 157 orr r3, r3, #0x00100000 158 orr r3, r3, #(L1_S_AP_KRW) 159 orr r3, r3, #(L1_TYPE_S) 160 orr r3, r3, #(L1_S_DOM_KERNEL) 161 str r3, [r0], #4 162 163 /* BTUART */ 164 mov r3, #0x40000000 165 orr r3, r3, #0x00200000 166 orr r3, r3, #(L1_S_AP_KRW) 167 orr r3, r3, #(L1_TYPE_S) 168 orr r3, r3, #(L1_S_DOM_KERNEL) 169 str r3, [r0], #4 170 171#if 0 172 /* 173 * Cache cleanup. Not needed here? Slight speedup in booting. 174 */ 175 mov r3, #(XSCALE_DCACHE_SIZE) 176 subs r3, r3, #32 1771: 178 mcr p15, 0, r3, c7, c10, 2 179 subs r3, r3, #32 180 bne 1b 181 CPWAIT(r3) 182 183 /* Drain write buffer */ 184 mcr p15, 0, r6, c7, c10, 4 185#endif 186 187 /* 188 * Make domain control go ful fart. 189 * We probably could be slightly more sensible about this, 190 * but it'll be replaced soon anyway, so why bother. 191 */ 192 mov r0, #0xffffffff 193 mcr p15, 0, r0, c3, c0, 0 194 195 /* 196 * Relocate the kernel to where we want it, not where Redboot 197 * let's us load it. Don't bother jumping after this stage, 198 * we'll do that soon enough anyway, and to the correct virtual 199 * address space region I might add. 200 */ 201 adr r0, _C_LABEL(viper_start) /* start copy from here */ 202 add r0, r0, #SDRAM_START /* offset to SDRAM mapping */ 203 204 ldr r1, .Lcopy_size /* copy this much (bytes) */ 205 add r1, r1, #3 /* prepare for roundup */ 206 mov r1, r1, LSR #2 /* make it words */ 207 208 mov r2, #SDRAM_START /* target address, */ 209 add r2, r2, #0x00200000 /* kernel offsets by 2megs */ 210 211 /* after this it's just a load-store-loop */ 2121: 213 ldr r3, [r0], #4 214 str r3, [r2], #4 215 subs r1, r1, #1 216 bgt 1b 217 218 /* 219 * Now let's clean the cache again to make sure everything 220 * is in place. 221 * 222 * XXX: should this take into account the XScale cache clean bug? 223 */ 224 mov r3, #(XSCALE_DCACHE_SIZE) 225 subs r3, r3, #32 2261: 227 mcr p15, 0, r3, c7, c10, 2 228 subs r3, r3, #32 229 bne 1b 230 CPWAIT(r3) 231 232 /* Drain write buffer */ 233 mcr p15, 0, r6, c7, c10, 4 234 235 /* Invalidate TLBs just to be sure */ 236 mcr p15, 0, r0, c8, c7, 0 237 238 /* 239 * You are standing at the gate to NetBSD. --More-- 240 * Unspeakable cruelty and harm lurk down there. --More-- 241 * Are you sure you want to enter? 242 */ 243 mov pc, r8 /* So be it */ 244 245/* symbol to use for address calculation in the right VA */ 246.Linva: 247 .word start 248 249/* 250 * Calculate size of kernel to copy. Don't bother to copy bss, 251 * although I guess the CPU could use the warmup exercise ... 252 */ 253.Lcopy_size: 254 .word _edata - _C_LABEL(viper_start) 255