📄 mmu.s
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/* ******************************************************
* @copyright(c) 版权所有，1998-2003微逻辑。保留所有权利。
* ******************************************************
*
* ******************************************************
* 文件说明：设置MMU
* 版本号：1.0.0
* 开发时期：2001-04-04
* 作者：李林
* 修改记录：
* *******************************************************
*/
.nolist
.include "def.inc"
.include "linkage.inc"
.list
.equ MemoryMap , 0x2a4 @ From ksarm.h - to get this to compile
.equ BANK_SIZE , 0x00100000 @ 1MB per bank in MemoryMap array
.equ BANK_SHIFT , 20
.equ USER_MODE , 0x10 @2_10000
.equ FIQ_MODE , 0x11 @2_10001
.equ IRQ_MODE , 0x12 @2_10010
.equ SVC_MODE , 0x13 @2_10011
.equ ABORT_MODE , 0x17 @2_10111
.equ UNDEF_MODE , 0x1b @2_11011
.equ SYS_MODE , 0x1f @2_11111
@
@ Define RAM space for the Page Tables:
@
@ High memory layout:
@ FFFD0000 - first level page table (uncached) (2nd half is r/o)
@ FFFD4000 - second level page tables (uncached)
@ FFFE0000 - disabled for protection
@ FFFF0000 - exception vectors
@ FFFF03E0 - exception vector jump table
@ FFFF0400 - not used (r/o)
@ FFFF1000 - disabled for protection
@ FFFF2000 - r/o (physical overlaps with vectors)
@ FFFF2400 - Interrupt stack (1k)
@ FFFF2800 - r/o (physical overlaps with Abort stack)
@ FFFF3000 - disabled for protection
@ FFFF4000 - r/o (physical memory overlaps with vectors & intr. stack & FIQ stack)
@ FFFF4900 - Abort stack (2k - 256 bytes)
@ FFFF5000 - disabled for protection
@ FFFF6000 - r/o (physical memory overlaps with vectors & intr. stack)
@ FFFF6800 - FIQ stack (256 bytes)
@ FFFF6900 - r/o (physical memory overlaps with Abort stack)
@ FFFF7000 - disabled
@ FFFFC000 - kernel stack
@ FFFFC800 - KDataStruct
@ FFFFCC00 - r/o for protection (2nd level page table for 0xFFF00000)
@ ^ 0xFFFD0000
@FirstPT # 0x4000
@PageTables # 0x4000
@ # 0x8000
@ # 0x10000 @ not mapped
@ExVector # 0x1000
@ # 0x1400 @ not mapped
@ # 0x0400 @ 1K interrupt stack
@IntStack # 0x2000 @ not mapped (ffff2800)
@ # 0x0100 @ not mapped (FIQ stack) (ffff4800)
@ # 0x0700 @ 2K-256 abort stack (ffff4900)
@AbortStack # 0x1800 @ not mapped (ffff5000)
@ # 0x0100 @ not mapped (FIQ stack) (ffff6800)
@FIQStack # 0xC000-0x6900 @ not mapped (ffff6900)
@KDBase # 0x07E0 @ 2K-32 kernel stack
@KStack # 0x0020 @ temporary register save area
@KData # 0x0400 @ kernel data area
.set BASE_PAGE_TABLE, 0xfffd0000
.set FirstPT, BASE_PAGE_TABLE
@ .set PageTables, FirstPT + 0x4000
.set UnusedPageTables, FirstPT + 0x4000 @ 不需要全局第二级页表，放到每一个线程 -2004-12-28 修改
.set _Notmaped1, UnusedPageTables + 0x4000
.set _Notmaped2, _Notmaped1 + 0x8000
.set ExVector, _Notmaped2 + 0x10000
.set _Notmaped3, ExVector + 0x1000
.set _Notmaped4, _Notmaped3 + 0x1400
.set IntStack, _Notmaped4 + 0x0400
.set _Notmaped5, IntStack + 0x2000
.set _Notmaped6, _Notmaped5 + 0x0100
.set AbortStack, _Notmaped6 + 0x0700
.set _Notmaped7, AbortStack+ 0x1800
.set FIQStack, _Notmaped7 + 0x0100
.set KDBase, FIQStack + 0xc000-0x6900+0x07e0
.set KStack, KDBase + 0x0020
.set KData, KStack + 0x0000
@-----------------------------------------------------------------------
@ .KDATA area is used to reserve physical memory for the above structures.
@AREA |.KDATA|,DATA,NOINIT
@EXPORT ExceptionVectorsArea
@EXPORT KDataArea
.globl KDataArea
.globl ExceptionVectorsArea
.section ".kdata", #alloc, #write
KDataArea:
PTs: .space 0x4000 @ space for first-level page table
@ 不需要全局第二级页表，放到每一个线程-2004-12-28 修改
@ .space 0x4000 @ space for 2nd-level page tables
@
ExceptionVectorsArea:
.space 0x0400 @ space for exception vectors
.space 0x0400 @ space for interrupt stack
.space 0x0100 @ space for fiq stack
.space 0x0700 @ space for abort stack
KPage: .space 0x0c00 @ space for kernel stack & kdatastruct
HighPT: .space 0x0400 @ space for 2nd level page table to map 0xfff00000
KDEnd:
@KDataArea
@PTs % 0x4000 @ space for first-level page table
@ % 0x4000 @ space for 2nd-level page tables
@ExceptionVectorsArea
@ % 0x0400 @ space for exception vectors
@ % 0x0400 @ space for interrupt stack
@ % 0x0100 @ space for FIQ stack
@ % 0x0700 @ space for Abort stack
@KPage % 0x0c00 @ space for kernel stack & KDataStruct
@HighPT % 0x0400 @ space for 2nd level page table to map 0xFFF00000
@KDEnd % 0
@ MACRO
@ mtc15 $cpureg, $cp15reg
@ mcr p15,0,$cpureg,$cp15reg,c0,0
@ MEND
@ MACRO
@ mfc15 $cpureg, $cp15reg
@ mrc p15,0,$cpureg,$cp15reg,c0,0
@ MEND
.macro mtc15, cpureg, cp15reg
mcr p15,0,\cpureg,\cp15reg,c0,0
.endm
.macro mfc15, cpureg, cp15reg
mrc p15,0,\cpureg,\cp15reg,c0,0
.endm
.text
.extern WriteByte
.extern _InitKernel
.extern TLBClear
.extern InitUart
.extern WriteString
.extern PutHex
.extern PutHex_Virtual
.extern LED_FLASH
.extern ES_VectorTable
@ TEXTAREA
@ IMPORT WriteByte
@ @IMPORT ES_InstallVectorTable
@ IMPORT ES_Entry
@ IMPORT TLBClear
@ @IMPORT main
@ @IMPORT EbootKernelStart
@ @IMPORT FlashCardLaunch
@ IMPORT InitUart
@ IMPORT WriteString
@ IMPORT PutHex
@IMPORT LED_FLASH
@ IMPORT ES_VectorTable
@=============================================================
@ Causes the SA1100 to transition to Idle mode
@=============================================================
ENTRY SetIdleMode
ldr r1, =0xA8000000
mcr p15,0,r0,c15,c2,2
ldr r0, [r1]
mcr p15,0,r0,c15,c8,2
nop
nop
nop
mov pc, lr
@=============================================================
@ Enable Dcache Cache
@=============================================================
ENTRY EnableDCache
mov r1, #0x0071 @ Enable: MMU
orr r1, r1, #0x1000 @ Enable icache, Dcache
orr r1, r1, #0x000C @ Enable dcache=4, write buffer=8
mtc15 r1, c1 @ enable the MMU & Caches
nop
mov pc, lr
@=============================================================
@ Disable Dcache Cache
@=============================================================
ENTRY DisableDCache
mov r1, #0x0071 @ Enable: MMU
orr r1, r1, #0x1000 @ Enable icache, Dcache
orr r1, r1, #0x0008 @ Enable dcache=4, write buffer=8
mtc15 r1, c1 @ enable the MMU & Caches
nop
mov pc, lr
@=============================================================
@ PhyAdrFromVirAdr: Figure out Physical Address of a Virtual Address
@
@ (r0) = VA
@ (r1) = ptr to OEMAddressTable
@
@ On return
@ (r0) = PA
@
@ Register used:
@ r0 - r3, r12
@
@=============================================================
ENTRY PhyAdrFromVirAdr
mov r12, r0 @ (r12) = VA
mov r0, #-1 @ (r0) = -1 (initialize return value to an invalid PA)
101:
ldr r3, [r1] @ (r3) = OEMAddressTable[i].vaddr
mov r2, r3, LSR #BANK_SHIFT @ make 1MB aligned
mov r3, r2, LSL #BANK_SHIFT
cmp r3, #0 @ EndOfTable?
moveq pc, lr @ INVALID OEMAddressTable, VA not found
cmp r12, r3 @ Is (VA >= OEMAddressTable[i].vaddr)?
blt 102f @ go to next entry if not
ldr r2, [r1, #8] @ (r2) = size in MB
add r2, r3, r2, LSL #BANK_SHIFT @ (r2) = OEMAddressTable[i].vaddr + region size
cmp r12, r2 @ Is (VA < OEMAddressTable[i].vaddr + region size)?
blt 103f @ Found if it's true
102:
add r1, r1, #12 @ i ++ (move to next entry)
b 101b @ test next entry
@ found the entry
@ (r1) = &OEMAddressTable[i]
@ (r3) = OEMAddressTable[i].vaddr
103:
ldr r0, [r1, #4] @ (r0) = OEMAddressTable[i].paddr
mov r0, r0, LSR #BANK_SHIFT @ (r0) >>= 20
add r0, r12, r0, LSL #BANK_SHIFT @ (r0) = VA + (r0 << 20)
sub r0, r0, r3 @ (r0) -= OEMAddressTable[i].vaddr
mov pc, lr @ return
@=============================================================
@ KernelStart - Set up the MMU and Dcache for bootloader
@
@ This routine will initialize the first-level page table based up the contents
@ of the MemoryMap array and enable the MMU and caches.
@
@ Entry (r0) = pointer to MemoryMap array in physical memory
@ Exit returns if MemoryMap is invalid
@@ Now If we are booting from Flash we want to copy and jump to RAM
@@ Otherwise if we are already in RAM we want to skip this step
@=============================================================
ENTRY _KernelStart
mov r11, r0 @ (r11) = &MemoryMap (save pointer)
ldr r9, =PTs @ (r9) = "virtual address" of 1st level table
ldr r7, =0x1FF00000 @ VA needs 512MB, 1MB aligned.
ldr r8, =0xFFF00000 @ PA needs 4GB, 1MB aligned.
and r6, r9, r7 @ (r6) = KDATA Virtual Address (1MB)
mov r1, r11 @ (r1) = ptr to MemoryMap array
5:
ldr r2, [r1], #4 @ (r2) = virtual address to map Bank at
ldr r3, [r1], #4 @ (r3) = physical address to map from
ldr r4, [r1], #4 @ (r4) = num MB to map
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