Luis Alves | 99e0837 | 2012-12-04 23:04:49 +0000 | [diff] [blame^] | 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 */ |