1 /* The head-file for the Shark
5 * - get the memory layout from firmware. This can only be done as long as the mmu
7 * - switch the mmu off, so we have physical addresses
8 * - copy the kernel to 0x08508000. This is done to have a fixed address where the
9 * C-parts (misc.c) are executed. This address must be known at compile-time,
10 * but the load-address of the kernel depends on how much memory is installed.
11 * - Jump to this location.
12 * - Set r8 with 0, r7 with the architecture ID for head.S
15 #include <linux/linkage.h>
17 #include <asm/assembler.h>
19 .section ".start", "ax"
24 __ofw_data: .long 0 @ the number of memory blocks
25 .space 128 @ (startaddr,size) ...
29 __beginning: mov r4, r0 @ save the entry to the firmware
31 mov r0, #0xC0 @ disable irq and fiq
38 mov r0, r4 @ get the Memory layout from firmware
45 adr r2, __mmu_off @ calculate physical address
46 sub r2, r2, #0xf0000000 @ openprom maps us at f000 virt, 0e50 phys
50 add r2, r2, #0x00500000
52 mrc p15, 0, r3, c1, c0
53 bic r3, r3, #0xC @ Write Buffer and DCache
54 bic r3, r3, #0x1000 @ ICache
55 mcr p15, 0, r3, c1, c0 @ disabled
58 mcr p15, 0, r0, c7, c7 @ flush I,D caches on v4
59 mcr p15, 0, r0, c7, c10, 4 @ drain write buffer on v4
60 mcr p15, 0, r0, c8, c7 @ flush I,D TLBs on v4
62 bic r3, r3, #0x1 @ MMU
63 mcr p15, 0, r3, c1, c0 @ disabled
67 __copy_target: .long 0x08507FFC
68 __copy_end: .long 0x08607FFC
74 __temp_stack: .space 128
77 adr r0, __ofw_data @ read the 1. entry of the memory map
79 orr r0, r0, #0x00600000
85 /* r0 = 0x0e600000 (current end of kernelcode)
86 * r3 = 0x08508000 (where it should begin)
87 * r1 = 0x08608000 (end of copying area, 1MB)
88 * The kernel is compressed, so 1 MB should be enough.
89 * copy the kernel to the beginning of physical memory
90 * We start from the highest address, so we can copy
91 * from 0x08500000 to 0x08508000 if we have only 8MB
94 /* As we get more 2.6-kernels it gets more and more
95 * uncomfortable to be bound to kernel images of 1MB only.
96 * So we add a loop here, to be able to copy some more.
97 * Alexander Schulz 2005-07-17
100 mov r4, #3 @ How many megabytes to copy
103 __MoveCode: sub r4, r4, #1
105 __Copy: ldr r2, [r0], #-4
110 /* The firmware maps us in blocks of 1 MB, the next block is
111 _below_ the last one. So our decrementing source pointer
112 ist right here, but the destination pointer must be increased
114 add r1, r1, #0x00200000
115 add r3, r3, #0x00100000
122 adr r2, __go_on @ where we want to jump
123 adr r0, __ofw_data @ read the 1. entry of the memory map
125 sub r2, r2, r0 @ we are mapped add 0e50 now, sub that (-0e00)
126 sub r2, r2, #0x00500000 @ -0050
127 ldr r0, __copy_target @ and add 0850 8000 instead
130 mov pc, r2 @ and jump there