forked from Minki/linux
246b49768b
Patch from Alexander Schulz Up to now, shark kernels were limited to one megabyte compressed size. As the kernels get bigger, this becomes more and more uncomfortable. So I added a loop to copy 3 MB instead of one and added some comments. Signed-off-by: Alexander Schulz <alex@shark-linux.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
140 lines
3.5 KiB
ArmAsm
140 lines
3.5 KiB
ArmAsm
/* 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
|