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/* 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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