| wdenk | 855a496 | 2004-03-14 18:23:55 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Memory Setup stuff - taken from blob memsetup.S |
| 3 | * |
| 4 | * Copyright (C) 1999 2000 2001 Erik Mouw (J.A.K.Mouw@its.tudelft.nl) and |
| 5 | * Jan-Derk Bakker (J.D.Bakker@its.tudelft.nl) |
| 6 | * 2003-2004 (c) MontaVista Software, Inc. |
| 7 | * |
| 8 | * See file CREDITS for list of people who contributed to this |
| 9 | * project. |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or |
| 12 | * modify it under the terms of the GNU General Public License as |
| 13 | * published by the Free Software Foundation; either version 2 of |
| 14 | * the License, or (at your option) any later version. |
| 15 | * |
| 16 | * This program is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | * GNU General Public License for more details. |
| 20 | * |
| 21 | * You should have received a copy of the GNU General Public License |
| 22 | * along with this program; if not, write to the Free Software |
| 23 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, |
| 24 | * MA 02111-1307 USA |
| 25 | */ |
| 26 | |
| 27 | |
| 28 | #include "config.h" |
| 29 | #include "version.h" |
| 30 | |
| 31 | |
| wdenk | 400558b | 2005-04-02 23:52:25 +0000 | [diff] [blame] | 32 | .globl lowlevel_init |
| 33 | lowlevel_init: |
| wdenk | 855a496 | 2004-03-14 18:23:55 +0000 | [diff] [blame] | 34 | /* The ADS GC+ for Linux Boot Rom Ver. 1.73 does memory init for us. |
| 35 | * However the darn thing leaves the MMU enabled before handing control |
| wdenk | 400558b | 2005-04-02 23:52:25 +0000 | [diff] [blame] | 36 | * over to us. So we need to disable the MMU and we use lowlevel_init |
| wdenk | 855a496 | 2004-03-14 18:23:55 +0000 | [diff] [blame] | 37 | * to do it. |
| 38 | */ |
| 39 | |
| 40 | @ The following code segment was borrowed with gratitude from: |
| 41 | @ linux-2.4.19-rmk7/arch/arm/boot/compressed/head-sa1100.S |
| 42 | |
| 43 | @ Data cache might be active. |
| 44 | @ Be sure to flush kernel binary out of the cache, |
| 45 | @ whatever state it is, before it is turned off. |
| 46 | @ This is done by fetching through currently executed |
| 47 | @ memory to be sure we hit the same cache. |
| 48 | bic r2, pc, #0x1f |
| 49 | add r3, r2, #0x4000 @ 16 kb is quite enough... |
| 50 | 1: ldr r0, [r2], #32 |
| 51 | teq r2, r3 |
| 52 | bne 1b |
| 53 | mcr p15, 0, r0, c7, c10, 4 @ drain WB |
| 54 | mcr p15, 0, r0, c7, c7, 0 @ flush I & D caches |
| 55 | |
| 56 | @ disabling MMU and caches |
| 57 | mrc p15, 0, r0, c1, c0, 0 @ read control reg |
| 58 | bic r0, r0, #0x0d @ clear WB, DC, MMU |
| 59 | bic r0, r0, #0x1000 @ clear Icache |
| 60 | mcr p15, 0, r0, c1, c0, 0 |
| 61 | |
| 62 | nop |
| 63 | nop |
| 64 | nop |
| 65 | nop |
| 66 | nop |
| 67 | |
| 68 | b 2f |
| 69 | 2: |
| 70 | nop |
| 71 | nop |
| 72 | nop |
| 73 | nop |
| 74 | nop |
| 75 | |
| 76 | |
| 77 | mov pc, lr |