diff options
Diffstat (limited to 'arch/avr32/boot/u-boot/head.S')
-rw-r--r-- | arch/avr32/boot/u-boot/head.S | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/arch/avr32/boot/u-boot/head.S b/arch/avr32/boot/u-boot/head.S new file mode 100644 index 000000000000..4488fa27fe94 --- /dev/null +++ b/arch/avr32/boot/u-boot/head.S | |||
@@ -0,0 +1,60 @@ | |||
1 | /* | ||
2 | * Startup code for use with the u-boot bootloader. | ||
3 | * | ||
4 | * Copyright (C) 2004-2006 Atmel Corporation | ||
5 | * | ||
6 | * This program is free software; you can redistribute it and/or modify | ||
7 | * it under the terms of the GNU General Public License version 2 as | ||
8 | * published by the Free Software Foundation. | ||
9 | */ | ||
10 | #include <asm/setup.h> | ||
11 | |||
12 | /* | ||
13 | * The kernel is loaded where we want it to be and all caches | ||
14 | * have just been flushed. We get two parameters from u-boot: | ||
15 | * | ||
16 | * r12 contains a magic number (ATAG_MAGIC) | ||
17 | * r11 points to a tag table providing information about | ||
18 | * the system. | ||
19 | */ | ||
20 | .section .init.text,"ax" | ||
21 | .global _start | ||
22 | _start: | ||
23 | /* Check if the boot loader actually provided a tag table */ | ||
24 | lddpc r0, magic_number | ||
25 | cp.w r12, r0 | ||
26 | brne no_tag_table | ||
27 | |||
28 | /* Initialize .bss */ | ||
29 | lddpc r2, bss_start_addr | ||
30 | lddpc r3, end_addr | ||
31 | mov r0, 0 | ||
32 | mov r1, 0 | ||
33 | 1: st.d r2++, r0 | ||
34 | cp r2, r3 | ||
35 | brlo 1b | ||
36 | |||
37 | /* | ||
38 | * Save the tag table address for later use. This must be done | ||
39 | * _after_ .bss has been initialized... | ||
40 | */ | ||
41 | lddpc r0, tag_table_addr | ||
42 | st.w r0[0], r11 | ||
43 | |||
44 | /* Jump to loader-independent setup code */ | ||
45 | rjmp kernel_entry | ||
46 | |||
47 | .align 2 | ||
48 | magic_number: | ||
49 | .long ATAG_MAGIC | ||
50 | tag_table_addr: | ||
51 | .long bootloader_tags | ||
52 | bss_start_addr: | ||
53 | .long __bss_start | ||
54 | end_addr: | ||
55 | .long _end | ||
56 | |||
57 | no_tag_table: | ||
58 | sub r12, pc, (. - 2f) | ||
59 | bral panic | ||
60 | 2: .asciz "Boot loader didn't provide correct magic number\n" | ||