167 lines
5.0 KiB
ArmAsm
167 lines
5.0 KiB
ArmAsm
/* $NetBSD: nslu2_start.S,v 1.2 2008/04/28 20:23:17 martin Exp $ */
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/*
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* Copyright (c) 2006 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Ichiro FUKUHARA, Jason R. Thorpe, and Steve C. Woodford.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <machine/asm.h>
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#include <arm/armreg.h>
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#include <arm/arm32/pte.h>
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#include <arm/xscale/ixp425reg.h>
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.section .start,"ax",%progbits
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.global _C_LABEL(nslu2_start)
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_C_LABEL(nslu2_start):
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/*
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* We will go ahead and disable the MMU here so that we don't
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* have to worry about flushing caches, etc.
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*
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* Note that we may not currently be running VA==PA, which means
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* we'll need to leap to the next insn after disabing the MMU.
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*/
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adr r8, Lunmapped
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bic r8, r8, #0xff000000 /* clear upper 8 bits */
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orr r8, r8, #0x10000000 /* OR in physical base address */
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mrc p15, 0, r2, c1, c0, 0
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bic r2, r2, #CPU_CONTROL_MMU_ENABLE
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orr r2, r2, #CPU_CONTROL_BEND_ENABLE
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mcr p15, 0, r2, c1, c0, 0
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nop
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nop
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nop
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mov pc, r8 /* Heave-ho! */
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Lunmapped:
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/*
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* We want to construct a memory map that maps us
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* VA==PA (SDRAM at 0x10000000). We create these
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* mappings uncached and unbuffered to be safe.
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*/
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/*
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* Step 1: Map the entire address space VA==PA.
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*/
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adr r0, Ltable
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ldr r0, [r0] /* r0 = &l1table */
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mov r1, #(L1_TABLE_SIZE / 4) /* 4096 entry */
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mov r2, #(L1_S_SIZE) /* 1MB / section */
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mov r3, #(L1_S_AP(AP_KRW)) /* kernel read/write */
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orr r3, r3, #(L1_TYPE_S) /* L1 entry is section */
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1:
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str r3, [r0], #0x04
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add r3, r3, r2
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subs r1, r1, #1
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bgt 1b
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/*
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* Step 2: Map VA 0xc0000000->0xc3ffffff to PA 0x10000000->0x13ffffff.
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*/
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adr r0, Ltable /* r0 = &l1table */
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ldr r0, [r0]
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mov r3, #(L1_S_AP(AP_KRW))
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orr r3, r3, #(L1_TYPE_S)
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orr r3, r3, #0x10000000
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add r0, r0, #(0xc00 * 4) /* offset to 0xc00xxxxx */
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mov r1, #0x40 /* 64MB */
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1:
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str r3, [r0], #0x04
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add r3, r3, r2
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subs r1, r1, #1
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bgt 1b
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/*
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* Step 3: Map VA 0xf0000000->0xf0100000 to PA 0xc8000000->0xc8100000.
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*/
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adr r0, Ltable /* r0 = &l1table */
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ldr r0, [r0]
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add r0, r0, #(0xf00 * 4) /* offset to 0xf0000000 */
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mov r3, #0xc8000000
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add r3, r3, #0x00100000
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orr r3, r3, #(L1_S_AP(AP_KRW))
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orr r3, r3, #(L1_TYPE_S)
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str r3, [r0]
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/*
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* Step 4: Map VA 0xf0200000->0xf0300000 to PA 0xcc000000->0xcc100000.
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*/
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adr r0, Ltable /* r0 = &l1table */
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ldr r0, [r0]
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add r0, r0, #(0xf00 * 4) /* offset to 0xf0200000 */
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add r0, r0, #(0x002 * 4)
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mov r3, #0xcc000000
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add r3, r3, #0x00100000
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orr r3, r3, #(L1_S_AP(AP_KRW))
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orr r3, r3, #(L1_TYPE_S)
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str r3, [r0]
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/* OK! Page table is set up. Give it to the CPU. */
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adr r0, Ltable
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ldr r0, [r0]
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mcr p15, 0, r0, c2, c0, 0
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/* Flush the old TLBs, just in case. */
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mcr p15, 0, r0, c8, c7, 0
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/* Set the Domain Access register. Very important! */
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mov r0, #1
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mcr p15, 0, r0, c3, c0, 0
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/* Get ready to jump to the "real" kernel entry point... */
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ldr r1, Lstart
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mov r1, r1 /* Make sure the load completes! */
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/* OK, let's enable the MMU. */
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mrc p15, 0, r2, c1, c0, 0
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orr r2, r2, #CPU_CONTROL_MMU_ENABLE
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orr r2, r2, #CPU_CONTROL_BEND_ENABLE
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mcr p15, 0, r2, c1, c0, 0
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nop
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nop
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nop
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/* CPWAIT sequence to make sure the MMU is on... */
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mrc p15, 0, r2, c2, c0, 0 /* arbitrary read of CP15 */
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mov r2, r2 /* force it to complete */
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mov pc, r1 /* leap to kernel entry point! */
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Ltable:
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.word 0x10200000 - 0x4000
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Lstart:
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.word start
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