linux/arch/xtensa/boot/boot-elf/bootstrap.S
Max Filippov e85e335f8f xtensa: add MMU v3 support
MMUv3 comes out of reset with identity vaddr -> paddr mapping in the TLB
way 6:

Way 6 (512 MB)
        Vaddr       Paddr       ASID  Attr RWX Cache
        ----------  ----------  ----  ---- --- -------
        0x00000000  0x00000000  0x01  0x03 RWX Bypass
        0x20000000  0x20000000  0x01  0x03 RWX Bypass
        0x40000000  0x40000000  0x01  0x03 RWX Bypass
        0x60000000  0x60000000  0x01  0x03 RWX Bypass
        0x80000000  0x80000000  0x01  0x03 RWX Bypass
        0xa0000000  0xa0000000  0x01  0x03 RWX Bypass
        0xc0000000  0xc0000000  0x01  0x03 RWX Bypass
        0xe0000000  0xe0000000  0x01  0x03 RWX Bypass

This patch adds remapping code at the reset vector or at the kernel
_start (depending on CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX) that
reconfigures MMUv3 as MMUv2:

Way 5 (128 MB)
        Vaddr       Paddr       ASID  Attr RWX Cache
        ----------  ----------  ----  ---- --- -------
        0xd0000000  0x00000000  0x01  0x07 RWX WB
        0xd8000000  0x00000000  0x01  0x03 RWX Bypass
Way 6 (256 MB)
        Vaddr       Paddr       ASID  Attr RWX Cache
        ----------  ----------  ----  ---- --- -------
        0xe0000000  0xf0000000  0x01  0x07 RWX WB
        0xf0000000  0xf0000000  0x01  0x03 RWX Bypass

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
2013-05-09 01:07:09 -07:00

105 lines
1.9 KiB
ArmAsm

/*
* arch/xtensa/boot/boot-elf/bootstrap.S
*
* Low-level exception handling
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2004 - 2013 by Tensilica Inc.
*
* Chris Zankel <chris@zankel.net>
* Marc Gauthier <marc@tensilica.com>
* Piet Delaney <piet@tensilica.com>
*/
#include <asm/bootparam.h>
#include <asm/processor.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/cacheasm.h>
#include <asm/initialize_mmu.h>
#include <linux/linkage.h>
.section .ResetVector.text, "ax"
.global _ResetVector
.global reset
_ResetVector:
_j _SetupMMU
.begin no-absolute-literals
.literal_position
.align 4
RomInitAddr:
#if defined(CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX) && \
XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY
.word 0x00003000
#else
.word 0xd0003000
#endif
RomBootParam:
.word _bootparam
_bootparam:
.short BP_TAG_FIRST
.short 4
.long BP_VERSION
.short BP_TAG_LAST
.short 0
.long 0
.align 4
_SetupMMU:
movi a0, 0
wsr a0, windowbase
rsync
movi a0, 1
wsr a0, windowstart
rsync
movi a0, 0x1F
wsr a0, ps
rsync
Offset = _SetupMMU - _ResetVector
#ifndef CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
initialize_mmu
#endif
.end no-absolute-literals
rsil a0, XCHAL_DEBUGLEVEL-1
rsync
reset:
l32r a0, RomInitAddr
l32r a2, RomBootParam
movi a3, 0
movi a4, 0
jx a0
.align 4
.section .ResetVector.remapped_text, "x"
.global _RemappedResetVector
/* Do org before literals */
.org 0
_RemappedResetVector:
.begin no-absolute-literals
.literal_position
_j _RemappedSetupMMU
/* Position Remapped code at the same location as the original code */
. = _RemappedResetVector + Offset
_RemappedSetupMMU:
#ifndef CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
initialize_mmu
#endif
.end no-absolute-literals