Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /*****************************************************************************/ |
| 2 | |
| 3 | /* |
| 4 | * head.S -- common startup code for ColdFire CPUs. |
| 5 | * |
| 6 | * (C) Copyright 1999-2004, Greg Ungerer (gerg@snapgear.com). |
| 7 | */ |
| 8 | |
| 9 | /*****************************************************************************/ |
| 10 | |
| 11 | #include <linux/config.h> |
| 12 | #include <linux/sys.h> |
| 13 | #include <linux/linkage.h> |
| 14 | #include <asm/asm-offsets.h> |
| 15 | #include <asm/coldfire.h> |
| 16 | #include <asm/mcfcache.h> |
| 17 | #include <asm/mcfsim.h> |
| 18 | |
| 19 | /*****************************************************************************/ |
| 20 | |
| 21 | /* |
| 22 | * Define fixed memory sizes. Configuration of a fixed memory size |
| 23 | * overrides everything else. If the user defined a size we just |
| 24 | * blindly use it (they know what they are doing right :-) |
| 25 | */ |
| 26 | #if defined(CONFIG_RAM32MB) |
| 27 | #define MEM_SIZE 0x02000000 /* memory size 32Mb */ |
| 28 | #elif defined(CONFIG_RAM16MB) |
| 29 | #define MEM_SIZE 0x01000000 /* memory size 16Mb */ |
| 30 | #elif defined(CONFIG_RAM8MB) |
| 31 | #define MEM_SIZE 0x00800000 /* memory size 8Mb */ |
| 32 | #elif defined(CONFIG_RAM4MB) |
| 33 | #define MEM_SIZE 0x00400000 /* memory size 4Mb */ |
| 34 | #elif defined(CONFIG_RAM1MB) |
| 35 | #define MEM_SIZE 0x00100000 /* memory size 1Mb */ |
| 36 | #endif |
| 37 | |
| 38 | /* |
| 39 | * Memory size exceptions for special cases. Some boards may be set |
| 40 | * for auto memory sizing, but we can't do it that way for some reason. |
| 41 | * For example the 5206eLITE board has static RAM, and auto-detecting |
| 42 | * the SDRAM will do you no good at all. |
| 43 | */ |
| 44 | #ifdef CONFIG_RAMAUTO |
| 45 | #if defined(CONFIG_M5206eLITE) |
| 46 | #define MEM_SIZE 0x00100000 /* 1MiB default memory */ |
| 47 | #endif |
| 48 | #endif /* CONFIG_RAMAUTO */ |
| 49 | |
| 50 | /* |
| 51 | * If we don't have a fixed memory size now, then lets build in code |
| 52 | * to auto detect the DRAM size. Obviously this is the prefered |
| 53 | * method, and should work for most boards (it won't work for those |
| 54 | * that do not have their RAM starting at address 0). |
| 55 | */ |
| 56 | #if defined(MEM_SIZE) |
| 57 | .macro GET_MEM_SIZE |
| 58 | movel #MEM_SIZE,%d0 /* hard coded memory size */ |
| 59 | .endm |
| 60 | |
| 61 | #elif defined(CONFIG_M5206) || defined(CONFIG_M5206e) || \ |
| 62 | defined(CONFIG_M5249) || defined(CONFIG_M527x) || \ |
| 63 | defined(CONFIG_M528x) || defined(CONFIG_M5307) || \ |
| 64 | defined(CONFIG_M5407) |
| 65 | /* |
| 66 | * Not all these devices have exactly the same DRAM controller, |
| 67 | * but the DCMR register is virtually identical - give or take |
| 68 | * a couple of bits. The only exception is the 5272 devices, their |
| 69 | * DRAM controller is quite different. |
| 70 | */ |
| 71 | .macro GET_MEM_SIZE |
| 72 | movel MCF_MBAR+MCFSIM_DMR0,%d0 /* get mask for 1st bank */ |
| 73 | btst #0,%d0 /* check if region enabled */ |
| 74 | beq 1f |
| 75 | andl #0xfffc0000,%d0 |
| 76 | beq 1f |
| 77 | addl #0x00040000,%d0 /* convert mask to size */ |
| 78 | 1: |
| 79 | movel MCF_MBAR+MCFSIM_DMR1,%d1 /* get mask for 2nd bank */ |
| 80 | btst #0,%d1 /* check if region enabled */ |
| 81 | beq 2f |
| 82 | andl #0xfffc0000, %d1 |
| 83 | beq 2f |
| 84 | addl #0x00040000,%d1 |
| 85 | addl %d1,%d0 /* total mem size in d0 */ |
| 86 | 2: |
| 87 | .endm |
| 88 | |
| 89 | #elif defined(CONFIG_M5272) |
| 90 | .macro GET_MEM_SIZE |
| 91 | movel MCF_MBAR+MCFSIM_CSOR7,%d0 /* get SDRAM address mask */ |
| 92 | andil #0xfffff000,%d0 /* mask out chip select options */ |
| 93 | negl %d0 /* negate bits */ |
| 94 | .endm |
| 95 | |
| 96 | #else |
| 97 | #error "ERROR: I don't know how to determine your boards memory size?" |
| 98 | #endif |
| 99 | |
| 100 | |
| 101 | /* |
| 102 | * Most ColdFire boards have their DRAM starting at address 0. |
| 103 | * Notable exception is the 5206eLITE board. |
| 104 | */ |
| 105 | #if defined(CONFIG_M5206eLITE) |
| 106 | #define MEM_BASE 0x30000000 |
| 107 | #endif |
| 108 | |
| 109 | #ifndef MEM_BASE |
| 110 | #define MEM_BASE 0x00000000 /* memory base at address 0 */ |
| 111 | #endif |
| 112 | |
| 113 | /* |
| 114 | * The default location for the vectors is at the base of RAM. |
| 115 | * Some boards might like to use internal SRAM or something like |
| 116 | * that. If no board specific header defines an alternative then |
| 117 | * use the base of RAM. |
| 118 | */ |
| 119 | #ifndef VBR_BASE |
| 120 | #define VBR_BASE MEM_BASE /* vector address */ |
| 121 | #endif |
| 122 | |
| 123 | /*****************************************************************************/ |
| 124 | |
| 125 | /* |
| 126 | * Boards and platforms can do specific early hardware setup if |
| 127 | * they need to. Most don't need this, define away if not required. |
| 128 | */ |
| 129 | #ifndef PLATFORM_SETUP |
| 130 | #define PLATFORM_SETUP |
| 131 | #endif |
| 132 | |
| 133 | /*****************************************************************************/ |
| 134 | |
| 135 | .global _start |
| 136 | .global _rambase |
| 137 | .global _ramvec |
| 138 | .global _ramstart |
| 139 | .global _ramend |
| 140 | |
| 141 | /*****************************************************************************/ |
| 142 | |
| 143 | .data |
| 144 | |
| 145 | /* |
| 146 | * During startup we store away the RAM setup. These are not in the |
| 147 | * bss, since their values are determined and written before the bss |
| 148 | * has been cleared. |
| 149 | */ |
| 150 | _rambase: |
| 151 | .long 0 |
| 152 | _ramvec: |
| 153 | .long 0 |
| 154 | _ramstart: |
| 155 | .long 0 |
| 156 | _ramend: |
| 157 | .long 0 |
| 158 | |
| 159 | /*****************************************************************************/ |
| 160 | |
| 161 | .text |
| 162 | |
| 163 | /* |
| 164 | * This is the codes first entry point. This is where it all |
| 165 | * begins... |
| 166 | */ |
| 167 | |
| 168 | _start: |
| 169 | nop /* filler */ |
| 170 | movew #0x2700, %sr /* no interrupts */ |
| 171 | |
| 172 | /* |
| 173 | * Do any platform or board specific setup now. Most boards |
| 174 | * don't need anything. Those exceptions are define this in |
| 175 | * their board specific includes. |
| 176 | */ |
| 177 | PLATFORM_SETUP |
| 178 | |
| 179 | /* |
| 180 | * Create basic memory configuration. Set VBR accordingly, |
| 181 | * and size memory. |
| 182 | */ |
| 183 | movel #VBR_BASE,%a7 |
| 184 | movec %a7,%VBR /* set vectors addr */ |
| 185 | movel %a7,_ramvec |
| 186 | |
| 187 | movel #MEM_BASE,%a7 /* mark the base of RAM */ |
| 188 | movel %a7,_rambase |
| 189 | |
| 190 | GET_MEM_SIZE /* macro code determines size */ |
| 191 | movel %d0,_ramend /* set end ram addr */ |
| 192 | |
| 193 | /* |
| 194 | * Now that we know what the memory is, lets enable cache |
| 195 | * and get things moving. This is Coldfire CPU specific. |
| 196 | */ |
| 197 | CACHE_ENABLE /* enable CPU cache */ |
| 198 | |
| 199 | |
| 200 | #ifdef CONFIG_ROMFS_FS |
| 201 | /* |
| 202 | * Move ROM filesystem above bss :-) |
| 203 | */ |
| 204 | lea _sbss,%a0 /* get start of bss */ |
| 205 | lea _ebss,%a1 /* set up destination */ |
| 206 | movel %a0,%a2 /* copy of bss start */ |
| 207 | |
| 208 | movel 8(%a0),%d0 /* get size of ROMFS */ |
| 209 | addql #8,%d0 /* allow for rounding */ |
| 210 | andl #0xfffffffc, %d0 /* whole words */ |
| 211 | |
| 212 | addl %d0,%a0 /* copy from end */ |
| 213 | addl %d0,%a1 /* copy from end */ |
| 214 | movel %a1,_ramstart /* set start of ram */ |
| 215 | |
| 216 | _copy_romfs: |
| 217 | movel -(%a0),%d0 /* copy dword */ |
| 218 | movel %d0,-(%a1) |
| 219 | cmpl %a0,%a2 /* check if at end */ |
| 220 | bne _copy_romfs |
| 221 | |
| 222 | #else /* CONFIG_ROMFS_FS */ |
| 223 | lea _ebss,%a1 |
| 224 | movel %a1,_ramstart |
| 225 | #endif /* CONFIG_ROMFS_FS */ |
| 226 | |
| 227 | |
| 228 | /* |
| 229 | * Zero out the bss region. |
| 230 | */ |
| 231 | lea _sbss,%a0 /* get start of bss */ |
| 232 | lea _ebss,%a1 /* get end of bss */ |
| 233 | clrl %d0 /* set value */ |
| 234 | _clear_bss: |
| 235 | movel %d0,(%a0)+ /* clear each word */ |
| 236 | cmpl %a0,%a1 /* check if at end */ |
| 237 | bne _clear_bss |
| 238 | |
| 239 | /* |
| 240 | * Load the current task pointer and stack. |
| 241 | */ |
| 242 | lea init_thread_union,%a0 |
| 243 | lea THREAD_SIZE(%a0),%sp |
| 244 | |
| 245 | /* |
| 246 | * Assember start up done, start code proper. |
| 247 | */ |
| 248 | jsr start_kernel /* start Linux kernel */ |
| 249 | |
| 250 | _exit: |
| 251 | jmp _exit /* should never get here */ |
| 252 | |
| 253 | /*****************************************************************************/ |