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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 | /* The head-file for the Shark
* by Alexander Schulz
*
* Does the following:
* - get the memory layout from firmware. This can only be done as long as the mmu
* is still on.
* - switch the mmu off, so we have physical addresses
* - copy the kernel to 0x08508000. This is done to have a fixed address where the
* C-parts (misc.c) are executed. This address must be known at compile-time,
* but the load-address of the kernel depends on how much memory is installed.
* - Jump to this location.
* - Set r8 with 0, r7 with the architecture ID for head.S
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
.section ".start", "ax"
b __beginning
__ofw_data: .long 0 @ the number of memory blocks
.space 128 @ (startaddr,size) ...
.space 128 @ bootargs
.align
__beginning: mov r4, r0 @ save the entry to the firmware
mov r0, #0xC0 @ disable irq and fiq
mov r1, r0
mrs r3, cpsr
bic r2, r3, r0
eor r2, r2, r1
msr cpsr_c, r2
mov r0, r4 @ get the Memory layout from firmware
adr r1, __ofw_data
add r2, r1, #4
mov lr, pc
b ofw_init
mov r1, #0
adr r2, __mmu_off @ calculate physical address
sub r2, r2, #0xf0000000 @ openprom maps us at f000 virt, 0e50 phys
adr r0, __ofw_data
ldr r0, [r0, #4]
add r2, r2, r0
add r2, r2, #0x00500000
mrc p15, 0, r3, c1, c0
bic r3, r3, #0xC @ Write Buffer and DCache
bic r3, r3, #0x1000 @ ICache
mcr p15, 0, r3, c1, c0 @ disabled
mov r0, #0
mcr p15, 0, r0, c7, c7 @ flush I,D caches on v4
mcr p15, 0, r0, c7, c10, 4 @ drain write buffer on v4
mcr p15, 0, r0, c8, c7 @ flush I,D TLBs on v4
bic r3, r3, #0x1 @ MMU
mcr p15, 0, r3, c1, c0 @ disabled
mov pc, r2
__copy_target: .long 0x08507FFC
__copy_end: .long 0x08607FFC
.word _start
.word __bss_start
.align
__temp_stack: .space 128
__mmu_off:
adr r0, __ofw_data @ read the 1. entry of the memory map
ldr r0, [r0, #4]
orr r0, r0, #0x00600000
sub r0, r0, #4
ldr r1, __copy_end
ldr r3, __copy_target
/* r0 = 0x0e600000 (current end of kernelcode)
* r3 = 0x08508000 (where it should begin)
* r1 = 0x08608000 (end of copying area, 1MB)
* The kernel is compressed, so 1 MB should be enough.
* copy the kernel to the beginning of physical memory
* We start from the highest address, so we can copy
* from 0x08500000 to 0x08508000 if we have only 8MB
*/
/* As we get more 2.6-kernels it gets more and more
* uncomfortable to be bound to kernel images of 1MB only.
* So we add a loop here, to be able to copy some more.
* Alexander Schulz 2005-07-17
*/
mov r4, #3 @ How many megabytes to copy
__MoveCode: sub r4, r4, #1
__Copy: ldr r2, [r0], #-4
str r2, [r1], #-4
teq r1, r3
bne __Copy
/* The firmware maps us in blocks of 1 MB, the next block is
_below_ the last one. So our decrementing source pointer
ist right here, but the destination pointer must be increased
by 2 MB */
add r1, r1, #0x00200000
add r3, r3, #0x00100000
teq r4, #0
bne __MoveCode
/* and jump to it */
adr r2, __go_on @ where we want to jump
adr r0, __ofw_data @ read the 1. entry of the memory map
ldr r0, [r0, #4]
sub r2, r2, r0 @ we are mapped add 0e50 now, sub that (-0e00)
sub r2, r2, #0x00500000 @ -0050
ldr r0, __copy_target @ and add 0850 8000 instead
add r0, r0, #4
add r2, r2, r0
mov pc, r2 @ and jump there
__go_on:
adr sp, __temp_stack
add sp, sp, #128
adr r0, __ofw_data
mov lr, pc
b create_params
mov r8, #0
mov r7, #15
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