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1/*
2 * Code that sets up the DRAM registers, calls the
3 * decompressor to unpack the piggybacked kernel, and jumps.
4 *
5 * Copyright (C) 1999 - 2006, Axis Communications AB
6 */
7
8#define ASSEMBLER_MACROS_ONLY
9#include <hwregs/asm/reg_map_asm.h>
10#include <mach/startup.inc>
11
12#define RAM_INIT_MAGIC 0x56902387
13#define COMMAND_LINE_MAGIC 0x87109563
14
15 ;; Exported symbols
16
17 .globl input_data
18
19 .text
20start:
21 di
22
23 ;; Start clocks for used blocks.
24 START_CLOCKS
25
26 ;; Initialize the DRAM registers.
27 cmp.d RAM_INIT_MAGIC, $r8 ; Already initialized?
28 beq dram_init_finished
29 nop
30
31#if defined CONFIG_ETRAXFS
32#include "../../arch-v32/mach-fs/dram_init.S"
33#elif defined CONFIG_CRIS_MACH_ARTPEC3
34#include "../../arch-v32/mach-a3/dram_init.S"
35#else
36#error Only ETRAXFS and ARTPEC-3 supported!
37#endif
38
39dram_init_finished:
40
41 GIO_INIT
42 ;; Setup the stack to a suitably high address.
43 ;; We assume 8 MB is the minimum DRAM and put
44 ;; the SP at the top for now.
45
46 move.d 0x40800000, $sp
47
48 ;; Figure out where the compressed piggyback image is.
49 ;; It is either in [NOR] flash (we don't want to copy it
50 ;; to DRAM before unpacking), or copied to DRAM
51 ;; by the [NAND] flash boot loader.
52 ;; The piggyback image is at _edata, but relative to where the
53 ;; image is actually located in memory, not where it is linked
54 ;; (the decompressor is linked at 0x40700000+ and runs there).
55 ;; Use (_edata - herami) as offset to the current PC.
56
57hereami:
58 lapcq ., $r5 ; get PC
59 and.d 0x7fffffff, $r5 ; strip any non-cache bit
60 move.d $r5, $r0 ; source address of 'herami'
61 add.d _edata, $r5
62 sub.d hereami, $r5 ; r5 = flash address of '_edata'
63 move.d hereami, $r1 ; destination
64
65 ;; Copy text+data to DRAM
66
67 move.d _edata, $r2 ; end destination
681: move.w [$r0+], $r3 ; from herami+ source
69 move.w $r3, [$r1+] ; to hereami+ destination (linked address)
70 cmp.d $r2, $r1 ; finish when destination == _edata
71 bcs 1b
72 nop
73 move.d input_data, $r0 ; for the decompressor
74 move.d $r5, [$r0] ; for the decompressor
75
76 ;; Clear the decompressors BSS (between _edata and _end)
77
78 moveq 0, $r0
79 move.d _edata, $r1
80 move.d _end, $r2
811: move.w $r0, [$r1+]
82 cmp.d $r2, $r1
83 bcs 1b
84 nop
85
86 ;; Save command line magic and address.
87 move.d _cmd_line_magic, $r0
88 move.d $r10, [$r0]
89 move.d _cmd_line_addr, $r0
90 move.d $r11, [$r0]
91
92 ;; Save boot source indicator
93 move.d _boot_source, $r0
94 move.d $r12, [$r0]
95
96 ;; Do the decompression and save compressed size in _inptr
97
98 jsr decompress_kernel
99 nop
100
101 ;; Restore boot source indicator
102 move.d _boot_source, $r12
103 move.d [$r12], $r12
104
105 ;; Restore command line magic and address.
106 move.d _cmd_line_magic, $r10
107 move.d [$r10], $r10
108 move.d _cmd_line_addr, $r11
109 move.d [$r11], $r11
110
111 ;; Put start address of root partition in r9 so the kernel can use it
112 ;; when mounting from flash
113 move.d input_data, $r0
114 move.d [$r0], $r9 ; flash address of compressed kernel
115 move.d inptr, $r0
116 add.d [$r0], $r9 ; size of compressed kernel
117 cmp.d 0x40000000, $r9 ; image in DRAM ?
118 blo enter_kernel ; no, must be [NOR] flash, jump
119 nop ; delay slot
120 and.d 0x001fffff, $r9 ; assume compressed kernel was < 2M
121
122enter_kernel:
123 ;; Enter the decompressed kernel
124 move.d RAM_INIT_MAGIC, $r8 ; Tell kernel that DRAM is initialized
125 jump 0x40004000 ; kernel is linked to this address
126 nop
127
128 .data
129
130input_data:
131 .dword 0 ; used by the decompressor
132_cmd_line_magic:
133 .dword 0
134_cmd_line_addr:
135 .dword 0
136_boot_source:
137 .dword 0
138
139#if defined CONFIG_ETRAXFS
140#include "../../arch-v32/mach-fs/hw_settings.S"
141#elif defined CONFIG_CRIS_MACH_ARTPEC3
142#include "../../arch-v32/mach-a3/hw_settings.S"
143#else
144#error Only ETRAXFS and ARTPEC-3 supported!
145#endif