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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
99e08374 LA |
2 | /* |
3 | * head.S - Common startup code for 68000 core based CPU's | |
4 | * | |
5 | * 2012.10.21, Luis Alves <ljalvs@gmail.com>, Single head.S file for all | |
6 | * 68000 core based CPU's. Based on the sources from: | |
7 | * Coldfire by Greg Ungerer <gerg@snapgear.com> | |
8 | * 68328 by D. Jeff Dionne <jeff@ryeham.ee.ryerson.ca>, | |
9 | * Kenneth Albanowski <kjahds@kjahds.com>, | |
10 | * The Silver Hammer Group, Ltd. | |
11 | * | |
12 | */ | |
13 | ||
14 | #include <linux/linkage.h> | |
15 | #include <linux/init.h> | |
16 | #include <asm/asm-offsets.h> | |
17 | #include <asm/thread_info.h> | |
18 | ||
19 | ||
20 | /***************************************************************************** | |
21 | * UCSIMM and UCDIMM use CONFIG_MEMORY_RESERVE to reserve some RAM | |
22 | *****************************************************************************/ | |
23 | #ifdef CONFIG_MEMORY_RESERVE | |
24 | #define RAMEND (CONFIG_RAMBASE+CONFIG_RAMSIZE)-(CONFIG_MEMORY_RESERVE*0x100000) | |
25 | #else | |
26 | #define RAMEND (CONFIG_RAMBASE+CONFIG_RAMSIZE) | |
27 | #endif | |
28 | /*****************************************************************************/ | |
29 | ||
30 | .global _start | |
31 | .global _rambase | |
32 | .global _ramvec | |
33 | .global _ramstart | |
34 | .global _ramend | |
35 | ||
36 | #if defined(CONFIG_PILOT) || defined(CONFIG_INIT_LCD) | |
37 | .global bootlogo_bits | |
38 | #endif | |
39 | ||
40 | /* Defining DEBUG_HEAD_CODE, serial port in 68x328 is inited */ | |
41 | /* #define DEBUG_HEAD_CODE */ | |
42 | #undef DEBUG_HEAD_CODE | |
43 | ||
44 | .data | |
45 | ||
46 | /***************************************************************************** | |
47 | * RAM setup pointers. Used by the kernel to determine RAM location and size. | |
48 | *****************************************************************************/ | |
49 | ||
50 | _rambase: | |
51 | .long 0 | |
52 | _ramvec: | |
53 | .long 0 | |
54 | _ramstart: | |
55 | .long 0 | |
56 | _ramend: | |
57 | .long 0 | |
58 | ||
59 | __HEAD | |
60 | ||
61 | /***************************************************************************** | |
62 | * Entry point, where all begins! | |
63 | *****************************************************************************/ | |
64 | ||
65 | _start: | |
66 | ||
67 | /* Pilot need this specific signature at the start of ROM */ | |
68 | #ifdef CONFIG_PILOT | |
69 | .byte 0x4e, 0xfa, 0x00, 0x0a /* bra opcode (jmp 10 bytes) */ | |
70 | .byte 'b', 'o', 'o', 't' | |
71 | .word 10000 | |
72 | nop | |
73 | moveq #0, %d0 | |
74 | movew %d0, 0xfffff618 /* Watchdog off */ | |
75 | movel #0x00011f07, 0xfffff114 /* CS A1 Mask */ | |
76 | #endif /* CONFIG_PILOT */ | |
77 | ||
78 | movew #0x2700, %sr /* disable all interrupts */ | |
79 | ||
80 | /***************************************************************************** | |
81 | * Setup PLL and wait for it to settle (in 68x328 cpu's). | |
82 | * Also, if enabled, init serial port. | |
83 | *****************************************************************************/ | |
84 | #if defined(CONFIG_M68328) || \ | |
85 | defined(CONFIG_M68EZ328) || \ | |
86 | defined(CONFIG_M68VZ328) | |
87 | ||
88 | /* Serial port setup. Should only be needed if debugging this startup code. */ | |
89 | #ifdef DEBUG_HEAD_CODE | |
90 | movew #0x0800, 0xfffff906 /* Ignore CTS */ | |
91 | movew #0x010b, 0xfffff902 /* BAUD to 9600 */ | |
92 | movew #0xe100, 0xfffff900 /* enable */ | |
93 | #endif /* DEBUG_HEAD */ | |
94 | ||
95 | #ifdef CONFIG_PILOT | |
96 | movew #0x2410, 0xfffff200 /* PLLCR */ | |
97 | #else | |
98 | movew #0x2400, 0xfffff200 /* PLLCR */ | |
99 | #endif | |
100 | movew #0x0123, 0xfffff202 /* PLLFSR */ | |
101 | moveq #0, %d0 | |
102 | movew #16384, %d0 /* PLL settle wait loop */ | |
103 | _pll_settle: | |
104 | subw #1, %d0 | |
105 | bne _pll_settle | |
106 | #endif /* CONFIG_M68x328 */ | |
107 | ||
108 | ||
109 | /***************************************************************************** | |
110 | * If running kernel from ROM some specific initialization has to be done. | |
111 | * (Assuming that everything is already init'ed when running from RAM) | |
112 | *****************************************************************************/ | |
113 | #ifdef CONFIG_ROMKERNEL | |
114 | ||
115 | /***************************************************************************** | |
116 | * Init chip registers (uCsimm specific) | |
117 | *****************************************************************************/ | |
118 | #ifdef CONFIG_UCSIMM | |
119 | moveb #0x00, 0xfffffb0b /* Watchdog off */ | |
120 | moveb #0x10, 0xfffff000 /* SCR */ | |
121 | moveb #0x00, 0xfffff40b /* enable chip select */ | |
122 | moveb #0x00, 0xfffff423 /* enable /DWE */ | |
123 | moveb #0x08, 0xfffffd0d /* disable hardmap */ | |
124 | moveb #0x07, 0xfffffd0e /* level 7 interrupt clear */ | |
125 | movew #0x8600, 0xfffff100 /* FLASH at 0x10c00000 */ | |
126 | movew #0x018b, 0xfffff110 /* 2Meg, enable, 0ws */ | |
127 | movew #0x8f00, 0xfffffc00 /* DRAM configuration */ | |
128 | movew #0x9667, 0xfffffc02 /* DRAM control */ | |
129 | movew #0x0000, 0xfffff106 /* DRAM at 0x00000000 */ | |
130 | movew #0x068f, 0xfffff116 /* 8Meg, enable, 0ws */ | |
131 | moveb #0x40, 0xfffff300 /* IVR */ | |
132 | movel #0x007FFFFF, %d0 /* IMR */ | |
133 | movel %d0, 0xfffff304 | |
134 | moveb 0xfffff42b, %d0 | |
135 | andb #0xe0, %d0 | |
136 | moveb %d0, 0xfffff42b | |
137 | #endif | |
138 | ||
139 | /***************************************************************************** | |
140 | * Init LCD controller. | |
141 | * (Assuming that LCD controller is already init'ed when running from RAM) | |
142 | *****************************************************************************/ | |
143 | #ifdef CONFIG_INIT_LCD | |
144 | #ifdef CONFIG_PILOT | |
145 | moveb #0, 0xfffffA27 /* LCKCON */ | |
146 | movel #_start, 0xfffffA00 /* LSSA */ | |
147 | moveb #0xa, 0xfffffA05 /* LVPW */ | |
148 | movew #0x9f, 0xFFFFFa08 /* LXMAX */ | |
149 | movew #0x9f, 0xFFFFFa0a /* LYMAX */ | |
150 | moveb #9, 0xfffffa29 /* LBAR */ | |
151 | moveb #0, 0xfffffa25 /* LPXCD */ | |
152 | moveb #0x04, 0xFFFFFa20 /* LPICF */ | |
153 | moveb #0x58, 0xfffffA27 /* LCKCON */ | |
154 | moveb #0x85, 0xfffff429 /* PFDATA */ | |
155 | moveb #0xd8, 0xfffffA27 /* LCKCON */ | |
156 | moveb #0xc5, 0xfffff429 /* PFDATA */ | |
157 | moveb #0xd5, 0xfffff429 /* PFDATA */ | |
158 | movel #bootlogo_bits, 0xFFFFFA00 /* LSSA */ | |
159 | moveb #10, 0xFFFFFA05 /* LVPW */ | |
160 | movew #160, 0xFFFFFA08 /* LXMAX */ | |
161 | movew #160, 0xFFFFFA0A /* LYMAX */ | |
162 | #else /* CONFIG_PILOT */ | |
163 | movel #bootlogo_bits, 0xfffffA00 /* LSSA */ | |
164 | moveb #0x28, 0xfffffA05 /* LVPW */ | |
165 | movew #0x280, 0xFFFFFa08 /* LXMAX */ | |
166 | movew #0x1df, 0xFFFFFa0a /* LYMAX */ | |
167 | moveb #0, 0xfffffa29 /* LBAR */ | |
168 | moveb #0, 0xfffffa25 /* LPXCD */ | |
169 | moveb #0x08, 0xFFFFFa20 /* LPICF */ | |
170 | moveb #0x01, 0xFFFFFA21 /* -ve pol */ | |
171 | moveb #0x81, 0xfffffA27 /* LCKCON */ | |
172 | movew #0xff00, 0xfffff412 /* LCD pins */ | |
173 | #endif /* CONFIG_PILOT */ | |
174 | #endif /* CONFIG_INIT_LCD */ | |
175 | ||
176 | /***************************************************************************** | |
177 | * Kernel is running from FLASH/ROM (XIP) | |
178 | * Copy init text & data to RAM | |
179 | *****************************************************************************/ | |
180 | moveal #_etext, %a0 | |
181 | moveal #_sdata, %a1 | |
182 | moveal #__bss_start, %a2 | |
183 | _copy_initmem: | |
184 | movel %a0@+, %a1@+ | |
185 | cmpal %a1, %a2 | |
186 | bhi _copy_initmem | |
187 | #endif /* CONFIG_ROMKERNEL */ | |
188 | ||
189 | /***************************************************************************** | |
190 | * Setup basic memory information for kernel | |
191 | *****************************************************************************/ | |
192 | movel #CONFIG_VECTORBASE,_ramvec /* set vector base location */ | |
193 | movel #CONFIG_RAMBASE,_rambase /* set the base of RAM */ | |
194 | movel #RAMEND, _ramend /* set end ram addr */ | |
195 | lea __bss_stop,%a1 | |
196 | movel %a1,_ramstart | |
197 | ||
198 | /***************************************************************************** | |
199 | * If the kernel is in RAM, move romfs to right above bss and | |
200 | * adjust _ramstart to where romfs ends. | |
201 | * | |
202 | * (Do this only if CONFIG_MTD_UCLINUX is true) | |
203 | *****************************************************************************/ | |
204 | ||
205 | #if defined(CONFIG_ROMFS_FS) && defined(CONFIG_RAMKERNEL) && \ | |
206 | defined(CONFIG_MTD_UCLINUX) | |
207 | lea __bss_start, %a0 /* get start of bss */ | |
208 | lea __bss_stop, %a1 /* set up destination */ | |
209 | movel %a0, %a2 /* copy of bss start */ | |
210 | ||
211 | movel 8(%a0), %d0 /* get size of ROMFS */ | |
212 | addql #8, %d0 /* allow for rounding */ | |
213 | andl #0xfffffffc, %d0 /* whole words */ | |
214 | ||
215 | addl %d0, %a0 /* copy from end */ | |
216 | addl %d0, %a1 /* copy from end */ | |
217 | movel %a1, _ramstart /* set start of ram */ | |
218 | _copy_romfs: | |
219 | movel -(%a0), -(%a1) /* copy dword */ | |
220 | cmpl %a0, %a2 /* check if at end */ | |
221 | bne _copy_romfs | |
222 | #endif /* CONFIG_ROMFS_FS && CONFIG_RAMKERNEL && CONFIG_MTD_UCLINUX */ | |
223 | ||
224 | /***************************************************************************** | |
225 | * Clear bss region | |
226 | *****************************************************************************/ | |
227 | lea __bss_start, %a0 /* get start of bss */ | |
228 | lea __bss_stop, %a1 /* get end of bss */ | |
229 | _clear_bss: | |
230 | movel #0, (%a0)+ /* clear each word */ | |
231 | cmpl %a0, %a1 /* check if at end */ | |
232 | bne _clear_bss | |
233 | ||
234 | /***************************************************************************** | |
235 | * Load the current task pointer and stack. | |
236 | *****************************************************************************/ | |
237 | lea init_thread_union,%a0 | |
238 | lea THREAD_SIZE(%a0),%sp | |
239 | jsr start_kernel /* start Linux kernel */ | |
240 | _exit: | |
241 | jmp _exit /* should never get here */ |