| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
|---|
| 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 */ |
|---|
| 242 | |
|---|
