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99e08374 LA |
1 | /* |
2 | * head.S - Common startup code for 68000 core based CPU's | |
3 | * | |
4 | * 2012.10.21, Luis Alves <ljalvs@gmail.com>, Single head.S file for all | |
5 | * 68000 core based CPU's. Based on the sources from: | |
6 | * Coldfire by Greg Ungerer <gerg@snapgear.com> | |
7 | * 68328 by D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>, | |
8 | * Kenneth Albanowski <kjahds@kjahds.com>, | |
9 | * The Silver Hammer Group, Ltd. | |
10 | * | |
11 | */ | |
12 | ||
13 | #include <linux/linkage.h> | |
14 | #include <linux/init.h> | |
15 | #include <asm/asm-offsets.h> | |
16 | #include <asm/thread_info.h> | |
17 | ||
18 | ||
19 | /***************************************************************************** | |
20 | * UCSIMM and UCDIMM use CONFIG_MEMORY_RESERVE to reserve some RAM | |
21 | *****************************************************************************/ | |
22 | #ifdef CONFIG_MEMORY_RESERVE | |
23 | #define RAMEND (CONFIG_RAMBASE+CONFIG_RAMSIZE)-(CONFIG_MEMORY_RESERVE*0x100000) | |
24 | #else | |
25 | #define RAMEND (CONFIG_RAMBASE+CONFIG_RAMSIZE) | |
26 | #endif | |
27 | /*****************************************************************************/ | |
28 | ||
29 | .global _start | |
30 | .global _rambase | |
31 | .global _ramvec | |
32 | .global _ramstart | |
33 | .global _ramend | |
34 | ||
35 | #if defined(CONFIG_PILOT) || defined(CONFIG_INIT_LCD) | |
36 | .global bootlogo_bits | |
37 | #endif | |
38 | ||
39 | /* Defining DEBUG_HEAD_CODE, serial port in 68x328 is inited */ | |
40 | /* #define DEBUG_HEAD_CODE */ | |
41 | #undef DEBUG_HEAD_CODE | |
42 | ||
43 | .data | |
44 | ||
45 | /***************************************************************************** | |
46 | * RAM setup pointers. Used by the kernel to determine RAM location and size. | |
47 | *****************************************************************************/ | |
48 | ||
49 | _rambase: | |
50 | .long 0 | |
51 | _ramvec: | |
52 | .long 0 | |
53 | _ramstart: | |
54 | .long 0 | |
55 | _ramend: | |
56 | .long 0 | |
57 | ||
58 | __HEAD | |
59 | ||
60 | /***************************************************************************** | |
61 | * Entry point, where all begins! | |
62 | *****************************************************************************/ | |
63 | ||
64 | _start: | |
65 | ||
66 | /* Pilot need this specific signature at the start of ROM */ | |
67 | #ifdef CONFIG_PILOT | |
68 | .byte 0x4e, 0xfa, 0x00, 0x0a /* bra opcode (jmp 10 bytes) */ | |
69 | .byte 'b', 'o', 'o', 't' | |
70 | .word 10000 | |
71 | nop | |
72 | moveq #0, %d0 | |
73 | movew %d0, 0xfffff618 /* Watchdog off */ | |
74 | movel #0x00011f07, 0xfffff114 /* CS A1 Mask */ | |
75 | #endif /* CONFIG_PILOT */ | |
76 | ||
77 | movew #0x2700, %sr /* disable all interrupts */ | |
78 | ||
79 | /***************************************************************************** | |
80 | * Setup PLL and wait for it to settle (in 68x328 cpu's). | |
81 | * Also, if enabled, init serial port. | |
82 | *****************************************************************************/ | |
83 | #if defined(CONFIG_M68328) || \ | |
84 | defined(CONFIG_M68EZ328) || \ | |
85 | defined(CONFIG_M68VZ328) | |
86 | ||
87 | /* Serial port setup. Should only be needed if debugging this startup code. */ | |
88 | #ifdef DEBUG_HEAD_CODE | |
89 | movew #0x0800, 0xfffff906 /* Ignore CTS */ | |
90 | movew #0x010b, 0xfffff902 /* BAUD to 9600 */ | |
91 | movew #0xe100, 0xfffff900 /* enable */ | |
92 | #endif /* DEBUG_HEAD */ | |
93 | ||
94 | #ifdef CONFIG_PILOT | |
95 | movew #0x2410, 0xfffff200 /* PLLCR */ | |
96 | #else | |
97 | movew #0x2400, 0xfffff200 /* PLLCR */ | |
98 | #endif | |
99 | movew #0x0123, 0xfffff202 /* PLLFSR */ | |
100 | moveq #0, %d0 | |
101 | movew #16384, %d0 /* PLL settle wait loop */ | |
102 | _pll_settle: | |
103 | subw #1, %d0 | |
104 | bne _pll_settle | |
105 | #endif /* CONFIG_M68x328 */ | |
106 | ||
107 | ||
108 | /***************************************************************************** | |
109 | * If running kernel from ROM some specific initialization has to be done. | |
110 | * (Assuming that everything is already init'ed when running from RAM) | |
111 | *****************************************************************************/ | |
112 | #ifdef CONFIG_ROMKERNEL | |
113 | ||
114 | /***************************************************************************** | |
115 | * Init chip registers (uCsimm specific) | |
116 | *****************************************************************************/ | |
117 | #ifdef CONFIG_UCSIMM | |
118 | moveb #0x00, 0xfffffb0b /* Watchdog off */ | |
119 | moveb #0x10, 0xfffff000 /* SCR */ | |
120 | moveb #0x00, 0xfffff40b /* enable chip select */ | |
121 | moveb #0x00, 0xfffff423 /* enable /DWE */ | |
122 | moveb #0x08, 0xfffffd0d /* disable hardmap */ | |
123 | moveb #0x07, 0xfffffd0e /* level 7 interrupt clear */ | |
124 | movew #0x8600, 0xfffff100 /* FLASH at 0x10c00000 */ | |
125 | movew #0x018b, 0xfffff110 /* 2Meg, enable, 0ws */ | |
126 | movew #0x8f00, 0xfffffc00 /* DRAM configuration */ | |
127 | movew #0x9667, 0xfffffc02 /* DRAM control */ | |
128 | movew #0x0000, 0xfffff106 /* DRAM at 0x00000000 */ | |
129 | movew #0x068f, 0xfffff116 /* 8Meg, enable, 0ws */ | |
130 | moveb #0x40, 0xfffff300 /* IVR */ | |
131 | movel #0x007FFFFF, %d0 /* IMR */ | |
132 | movel %d0, 0xfffff304 | |
133 | moveb 0xfffff42b, %d0 | |
134 | andb #0xe0, %d0 | |
135 | moveb %d0, 0xfffff42b | |
136 | #endif | |
137 | ||
138 | /***************************************************************************** | |
139 | * Init LCD controller. | |
140 | * (Assuming that LCD controller is already init'ed when running from RAM) | |
141 | *****************************************************************************/ | |
142 | #ifdef CONFIG_INIT_LCD | |
143 | #ifdef CONFIG_PILOT | |
144 | moveb #0, 0xfffffA27 /* LCKCON */ | |
145 | movel #_start, 0xfffffA00 /* LSSA */ | |
146 | moveb #0xa, 0xfffffA05 /* LVPW */ | |
147 | movew #0x9f, 0xFFFFFa08 /* LXMAX */ | |
148 | movew #0x9f, 0xFFFFFa0a /* LYMAX */ | |
149 | moveb #9, 0xfffffa29 /* LBAR */ | |
150 | moveb #0, 0xfffffa25 /* LPXCD */ | |
151 | moveb #0x04, 0xFFFFFa20 /* LPICF */ | |
152 | moveb #0x58, 0xfffffA27 /* LCKCON */ | |
153 | moveb #0x85, 0xfffff429 /* PFDATA */ | |
154 | moveb #0xd8, 0xfffffA27 /* LCKCON */ | |
155 | moveb #0xc5, 0xfffff429 /* PFDATA */ | |
156 | moveb #0xd5, 0xfffff429 /* PFDATA */ | |
157 | movel #bootlogo_bits, 0xFFFFFA00 /* LSSA */ | |
158 | moveb #10, 0xFFFFFA05 /* LVPW */ | |
159 | movew #160, 0xFFFFFA08 /* LXMAX */ | |
160 | movew #160, 0xFFFFFA0A /* LYMAX */ | |
161 | #else /* CONFIG_PILOT */ | |
162 | movel #bootlogo_bits, 0xfffffA00 /* LSSA */ | |
163 | moveb #0x28, 0xfffffA05 /* LVPW */ | |
164 | movew #0x280, 0xFFFFFa08 /* LXMAX */ | |
165 | movew #0x1df, 0xFFFFFa0a /* LYMAX */ | |
166 | moveb #0, 0xfffffa29 /* LBAR */ | |
167 | moveb #0, 0xfffffa25 /* LPXCD */ | |
168 | moveb #0x08, 0xFFFFFa20 /* LPICF */ | |
169 | moveb #0x01, 0xFFFFFA21 /* -ve pol */ | |
170 | moveb #0x81, 0xfffffA27 /* LCKCON */ | |
171 | movew #0xff00, 0xfffff412 /* LCD pins */ | |
172 | #endif /* CONFIG_PILOT */ | |
173 | #endif /* CONFIG_INIT_LCD */ | |
174 | ||
175 | /***************************************************************************** | |
176 | * Kernel is running from FLASH/ROM (XIP) | |
177 | * Copy init text & data to RAM | |
178 | *****************************************************************************/ | |
179 | moveal #_etext, %a0 | |
180 | moveal #_sdata, %a1 | |
181 | moveal #__bss_start, %a2 | |
182 | _copy_initmem: | |
183 | movel %a0@+, %a1@+ | |
184 | cmpal %a1, %a2 | |
185 | bhi _copy_initmem | |
186 | #endif /* CONFIG_ROMKERNEL */ | |
187 | ||
188 | /***************************************************************************** | |
189 | * Setup basic memory information for kernel | |
190 | *****************************************************************************/ | |
191 | movel #CONFIG_VECTORBASE,_ramvec /* set vector base location */ | |
192 | movel #CONFIG_RAMBASE,_rambase /* set the base of RAM */ | |
193 | movel #RAMEND, _ramend /* set end ram addr */ | |
194 | lea __bss_stop,%a1 | |
195 | movel %a1,_ramstart | |
196 | ||
197 | /***************************************************************************** | |
198 | * If the kernel is in RAM, move romfs to right above bss and | |
199 | * adjust _ramstart to where romfs ends. | |
200 | * | |
201 | * (Do this only if CONFIG_MTD_UCLINUX is true) | |
202 | *****************************************************************************/ | |
203 | ||
204 | #if defined(CONFIG_ROMFS_FS) && defined(CONFIG_RAMKERNEL) && \ | |
205 | defined(CONFIG_MTD_UCLINUX) | |
206 | lea __bss_start, %a0 /* get start of bss */ | |
207 | lea __bss_stop, %a1 /* set up destination */ | |
208 | movel %a0, %a2 /* copy of bss start */ | |
209 | ||
210 | movel 8(%a0), %d0 /* get size of ROMFS */ | |
211 | addql #8, %d0 /* allow for rounding */ | |
212 | andl #0xfffffffc, %d0 /* whole words */ | |
213 | ||
214 | addl %d0, %a0 /* copy from end */ | |
215 | addl %d0, %a1 /* copy from end */ | |
216 | movel %a1, _ramstart /* set start of ram */ | |
217 | _copy_romfs: | |
218 | movel -(%a0), -(%a1) /* copy dword */ | |
219 | cmpl %a0, %a2 /* check if at end */ | |
220 | bne _copy_romfs | |
221 | #endif /* CONFIG_ROMFS_FS && CONFIG_RAMKERNEL && CONFIG_MTD_UCLINUX */ | |
222 | ||
223 | /***************************************************************************** | |
224 | * Clear bss region | |
225 | *****************************************************************************/ | |
226 | lea __bss_start, %a0 /* get start of bss */ | |
227 | lea __bss_stop, %a1 /* get end of bss */ | |
228 | _clear_bss: | |
229 | movel #0, (%a0)+ /* clear each word */ | |
230 | cmpl %a0, %a1 /* check if at end */ | |
231 | bne _clear_bss | |
232 | ||
233 | /***************************************************************************** | |
234 | * Load the current task pointer and stack. | |
235 | *****************************************************************************/ | |
236 | lea init_thread_union,%a0 | |
237 | lea THREAD_SIZE(%a0),%sp | |
238 | jsr start_kernel /* start Linux kernel */ | |
239 | _exit: | |
240 | jmp _exit /* should never get here */ |