diff options
Diffstat (limited to 'arch/arm/boot/compressed/head-shark.S')
| -rw-r--r-- | arch/arm/boot/compressed/head-shark.S | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/arch/arm/boot/compressed/head-shark.S b/arch/arm/boot/compressed/head-shark.S new file mode 100644 index 00000000..089c560e --- /dev/null +++ b/arch/arm/boot/compressed/head-shark.S @@ -0,0 +1,139 @@ +/* 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 |