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wdenk4a551702003-10-08 23:26:14 +00001/*
2 * (C) Copyright 2003, Psyent Corporation <www.psyent.com>
3 * Scott McNutt <smcnutt@psyent.com>
4 *
5 * See file CREDITS for list of people who contributed to this
6 * project.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21 * MA 02111-1307 USA
22 */
23
24
25#include <config.h>
Peter Tyser561858e2008-11-03 09:30:59 -060026#include <timestamp.h>
wdenk4a551702003-10-08 23:26:14 +000027#include <version.h>
28
29#if !defined(CONFIG_IDENT_STRING)
30#define CONFIG_IDENT_STRING ""
31#endif
32
33#define STATUS_INIT 0x8600 /* IE=1, IPRI=2 */
34
35/*************************************************************************
36 * RESTART
37 ************************************************************************/
38
39 .text
40 .global _start
41
42_start:
43 bsr 0f
44 nop
45 .long _start
46
47 /* GERMS -- The "standard-32" configuration GERMS monitor looks
48 * for the string "Nios" at flash_base + 0xc (actually it only
49 * tests for 'N', 'i'). You can leave support for this in place
50 * as it's only a few words.
51 */
52 . = _start + 0x000c
53 .string "Nios"
54
55 .align 4
560:
57 /*
58 * Early setup -- set cwp = HI_LIMIT, IPRI = 2, IE = 1 to
59 * enable underflow exceptions. Disable cache.
60 * NOTE: %o7 has return addr -- save in %g7 use later.
61 */
62 mov %g7, %o7
63
64 pfx 2 /* WVALID */
65 rdctl %g0
66 lsri %g0, 1
67 pfx %hi(STATUS_INIT)
68 or %g0, %lo(STATUS_INIT)
69 wrctl %g0 /* update status */
70 nop
71
72 /*
73 * STACK
74 */
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +020075 pfx %hi(CONFIG_SYS_INIT_SP)
76 movi %sp, %lo(CONFIG_SYS_INIT_SP)
77 pfx %xhi(CONFIG_SYS_INIT_SP)
78 movhi %sp, %xlo(CONFIG_SYS_INIT_SP)
wdenk4a551702003-10-08 23:26:14 +000079 mov %fp, %sp
80
81 pfx %hi(4*16)
82 subi %sp, %lo(4*16) /* Space for reg window mgmt */
83
84 /*
85 * RELOCATE -- %g7 has return addr from bsr at _start.
86 */
87 pfx %hi(__u_boot_cmd_end)
88 movi %g5, %lo(__u_boot_cmd_end)
89 pfx %xhi(__u_boot_cmd_end)
90 movhi %g5, %xlo(__u_boot_cmd_end) /* %g5 <- end address */
91
92 lsli %g7, 1 /* mem = retaddr << 1 */
93 mov %g6, %g7
94 subi %g6, 4 /* %g6 <- src addr */
95 ld %g7, [%g7] /* %g7 <- dst addr */
96
wdenke4cc71a2004-05-19 21:33:14 +000097 /* No need to move text sections if we're already located
98 * at the proper address.
99 */
100 cmp %g7, %g6
101 ifs cc_z
102 br reloc
103 nop /* delay slot */
104
wdenk4a551702003-10-08 23:26:14 +00001051: cmp %g7, %g5
106 skps cc_nz
107 br 2f
108 nop /* delay slot */
109
110 ld %g0, [%g6]
111 addi %g6, 4 /* src++ */
112 st [%g7], %g0
113 addi %g7, 4 /* dst++ */
114 br 1b
115 nop /* delay slot */
1162:
117
118 /*
119 * Jump to relocation address
120 */
121 pfx %hi(reloc@h)
122 movi %g0, %lo(reloc@h)
123 pfx %xhi(reloc@h)
124 movhi %g0, %xlo(reloc@h)
125 jmp %g0
wdenke4cc71a2004-05-19 21:33:14 +0000126 nop /* delay slot */
wdenk4a551702003-10-08 23:26:14 +0000127reloc:
128
129 /*
130 * CLEAR BSS
131 */
132 pfx %hi(__bss_end)
133 movi %g5, %lo(__bss_end)
134 pfx %xhi(__bss_end)
135 movhi %g5, %xlo(__bss_end) /* %g5 <- end address */
136 pfx %hi(__bss_start)
137 movi %g7, %lo(__bss_start)
138 pfx %xhi(__bss_start)
139 movhi %g7, %xlo(__bss_start) /* %g7 <- end address */
140
141 movi %g0, 0
1423: cmp %g7, %g5
143 skps cc_nz
144 br 4f
145 nop /* delay slot */
146
147 st [%g7], %g0
148 addi %g7, 4 /* (delay slot) dst++ */
149 br 3b
150 nop /* delay slot */
1514:
152
153 /*
wdenke4cc71a2004-05-19 21:33:14 +0000154 * INIT VECTOR TABLE
155 */
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200156 pfx %hi(CONFIG_SYS_VECT_BASE)
157 movi %g0, %lo(CONFIG_SYS_VECT_BASE)
158 pfx %xhi(CONFIG_SYS_VECT_BASE)
159 movhi %g0, %xlo(CONFIG_SYS_VECT_BASE) /* dst */
wdenke4cc71a2004-05-19 21:33:14 +0000160 mov %l0, %g0
161
162 pfx %hi(_vectors)
163 movi %g1, %lo(_vectors)
164 pfx %xhi(_vectors)
165 movhi %g1, %xlo(_vectors) /* src */
166 bgen %g2, 6 /* cnt = 64 */
167
168 ldp %g3, [%l0, 3] /* bkpt vector */
169 ldp %g4, [%l0, 4] /* single step vector */
170
1715: ld %g7, [%g1]
172 addi %g1, 4 /* src++ */
173 st [%g0], %g7
174 addi %g0, 4 /* dst++ */
175
176 subi %g2, 1 /* cnt-- */
177 ifrnz %g2
178 br 5b
179 nop /* delay slot */
180
181#if defined(CONFIG_ROM_STUBS)
182 /* Restore the breakpoint and single step exception
183 * vectors to their original values.
184 */
185 stp [%l0,3], %g3 /* breakpoint */
186 stp [%l0,4], %g4 /* single step */
187#endif
188
189 /* For debug startup convenience ... software breakpoints
190 * set prior to this point may not succeed ;-)
191 */
192 .global __start
193__start:
194
195 /*
wdenk4a551702003-10-08 23:26:14 +0000196 * Call board_init -- never returns
197 */
198 pfx %hi(board_init@h)
199 movi %g1, %lo(board_init@h)
200 pfx %xhi(board_init@h)
201 movhi %g1, %xlo(board_init@h)
202 call %g1
203 nop /* Delaly slot */
204 /* NEVER RETURNS */
205
206/*
207 * dly_clks -- Nios doesn't have a time/clk reference for simple
208 * delay loops, so we do our best by counting instruction cycles.
209 * A control register that counts system clock cycles would be
210 * a handy feature -- hint for Altera ;-)
211 */
Wolfgang Denk53677ef2008-05-20 16:00:29 +0200212 .globl dly_clks
wdenk4a551702003-10-08 23:26:14 +0000213 /* Each loop is 4 instructions as delay slot is always
214 * executed. Each instruction is approximately 4 clocks
215 * (according to some lame info from Altera). So ...
216 * ... each loop is about 16 clocks.
217 */
218
219dly_clks:
220 lsri %o0, 4 /* cnt/16 */
221
2228: skprnz %o0
223 br 9f
224 subi %o0, 1 /* cnt--, Delay slot */
225 br 8b
226 nop
227
2289: lret
229 nop /* Delay slot */
230
231
232 .data
233 .globl version_string
234
235version_string:
236 .ascii U_BOOT_VERSION
Peter Tyser561858e2008-11-03 09:30:59 -0600237 .ascii " (", U_BOOT_DATE, " - ", U_BOOT_TIME, ")"
wdenk4a551702003-10-08 23:26:14 +0000238 .ascii CONFIG_IDENT_STRING, "\0"