1/* $NetBSD: iq80310_start.S,v 1.5 2011/01/31 06:28:03 matt Exp $ */ 2 3/* 4 * Copyright (c) 2002 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Jason R. Thorpe for Wasabi Systems, Inc. 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 for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38#include <machine/asm.h> 39#include <arm/armreg.h> 40#include "assym.h" 41 42RCSID("$NetBSD: iq80310_start.S,v 1.5 2011/01/31 06:28:03 matt Exp $") 43 44 .section .start,"ax",%progbits 45 46 .global _C_LABEL(iq80310_start) 47_C_LABEL(iq80310_start): 48 /* 49 * We assume we've been loaded VA==PA, or that the MMU is 50 * disabled. We will go ahead and disable the MMU here 51 * so that we don't have to worry about flushing caches, etc. 52 */ 53 mrc p15, 0, r2, c1, c0, 0 54 bic r2, r2, #CPU_CONTROL_MMU_ENABLE 55 mcr p15, 0, r2, c1, c0, 0 56 57 nop 58 nop 59 nop 60 61 /* 62 * We want to construct a memory map that maps us 63 * VA==PA (SDRAM at 0xa0000000) and also double-maps 64 * that space at 0xc0000000 (where the kernel address 65 * space starts). We create these mappings uncached 66 * and unbuffered to be safe. 67 * 68 * We also want to map the various devices we want to 69 * talk to VA==PA during bootstrap. 70 * 71 * We just use section mappings for all of this to make it easy. 72 * 73 * We will put the L1 table to do all this at 0xa0004000, which 74 * is also where RedBoot puts it. 75 */ 76 77 /* 78 * Step 1: Map the entire address space VA==PA. 79 */ 80 adr r0, Ltable 81 ldr r0, [r0] /* r0 = &l1table */ 82 83 mov r3, #(L1_S_AP_KRW) 84 orr r3, r3, #(L1_TYPE_S) 85 mov r2, #0x100000 /* advance by 1MB */ 86 mov r1, #0x1000 /* 4096MB */ 871: 88 str r3, [r0], #0x04 89 add r3, r3, r2 90 subs r1, r1, #1 91 bgt 1b 92 93 /* 94 * Step 2: Map VA 0xc0000000->0xc3ffffff to PA 0xa0000000->0xa3ffffff. 95 */ 96 adr r0, Ltable /* r0 = &l1table */ 97 ldr r0, [r0] 98 99 mov r3, #(L1_S_AP_KRW) 100 orr r3, r3, #(L1_TYPE_S) 101 orr r3, r3, #0xa0000000 102 add r0, r0, #(0xc00 * 4) /* offset to 0xc00xxxxx */ 103 mov r1, #0x40 /* 64MB */ 1041: 105 str r3, [r0], #0x04 106 add r3, r3, r2 107 subs r1, r1, #1 108 bgt 1b 109 110 /* OK! Page table is set up. Give it to the CPU. */ 111 adr r0, Ltable 112 ldr r0, [r0] 113 mcr p15, 0, r0, c2, c0, 0 114 115 /* Flush the old TLBs, just in case. */ 116 mcr p15, 0, r0, c8, c7, 0 117 118 /* Set the Domain Access register. Very important! */ 119 mov r0, #1 120 mcr p15, 0, r0, c3, c0, 0 121 122 /* Get ready to jump to the "real" kernel entry point... */ 123 ldr r0, Lstart 124 125 /* OK, let's enable the MMU. */ 126 mrc p15, 0, r2, c1, c0, 0 127 orr r2, r2, #CPU_CONTROL_MMU_ENABLE 128 mcr p15, 0, r2, c1, c0, 0 129 130 nop 131 nop 132 nop 133 134 /* CPWAIT sequence to make sure the MMU is on... */ 135 mrc p15, 0, r2, c2, c0, 0 /* arbitrary read of CP15 */ 136 mov r2, r2 /* force it to complete */ 137 mov pc, r0 /* leap to kernel entry point! */ 138 139Ltable: 140 .word 0xa0004000 141 142Lstart: 143 .word start 144