1/*****************************************************************************/ 2 3/* 4 * head.S -- common startup code for ColdFire CPUs. 5 * 6 * (C) Copyright 1999-2011, Greg Ungerer <gerg@snapgear.com>. 7 */ 8 9/*****************************************************************************/ 10 11#include <linux/linkage.h> 12#include <linux/init.h> 13#include <asm/asm-offsets.h> 14#include <asm/coldfire.h> 15#include <asm/mcfsim.h> 16#include <asm/mcfmmu.h> 17#include <asm/thread_info.h> 18 19/*****************************************************************************/ 20 21/* 22 * If we don't have a fixed memory size, then lets build in code 23 * to auto detect the DRAM size. Obviously this is the preferred 24 * method, and should work for most boards. It won't work for those 25 * that do not have their RAM starting at address 0, and it only 26 * works on SDRAM (not boards fitted with SRAM). 27 */ 28#if CONFIG_RAMSIZE != 0 29.macro GET_MEM_SIZE 30 movel #CONFIG_RAMSIZE,%d0 /* hard coded memory size */ 31.endm 32 33#elif defined(CONFIG_M5206) || defined(CONFIG_M5206e) || \ 34 defined(CONFIG_M5249) || defined(CONFIG_M525x) || \ 35 defined(CONFIG_M527x) || defined(CONFIG_M528x) || \ 36 defined(CONFIG_M5307) || defined(CONFIG_M5407) 37/* 38 * Not all these devices have exactly the same DRAM controller, 39 * but the DCMR register is virtually identical - give or take 40 * a couple of bits. The only exception is the 5272 devices, their 41 * DRAM controller is quite different. 42 */ 43.macro GET_MEM_SIZE 44 movel MCFSIM_DMR0,%d0 /* get mask for 1st bank */ 45 btst #0,%d0 /* check if region enabled */ 46 beq 1f 47 andl #0xfffc0000,%d0 48 beq 1f 49 addl #0x00040000,%d0 /* convert mask to size */ 501: 51 movel MCFSIM_DMR1,%d1 /* get mask for 2nd bank */ 52 btst #0,%d1 /* check if region enabled */ 53 beq 2f 54 andl #0xfffc0000,%d1 55 beq 2f 56 addl #0x00040000,%d1 57 addl %d1,%d0 /* total mem size in d0 */ 582: 59.endm 60 61#elif defined(CONFIG_M5272) 62.macro GET_MEM_SIZE 63 movel MCFSIM_CSOR7,%d0 /* get SDRAM address mask */ 64 andil #0xfffff000,%d0 /* mask out chip select options */ 65 negl %d0 /* negate bits */ 66.endm 67 68#elif defined(CONFIG_M520x) 69.macro GET_MEM_SIZE 70 clrl %d0 71 movel MCFSIM_SDCS0, %d2 /* Get SDRAM chip select 0 config */ 72 andl #0x1f, %d2 /* Get only the chip select size */ 73 beq 3f /* Check if it is enabled */ 74 addql #1, %d2 /* Form exponent */ 75 moveql #1, %d0 76 lsll %d2, %d0 /* 2 ^ exponent */ 773: 78 movel MCFSIM_SDCS1, %d2 /* Get SDRAM chip select 1 config */ 79 andl #0x1f, %d2 /* Get only the chip select size */ 80 beq 4f /* Check if it is enabled */ 81 addql #1, %d2 /* Form exponent */ 82 moveql #1, %d1 83 lsll %d2, %d1 /* 2 ^ exponent */ 84 addl %d1, %d0 /* Total size of SDRAM in d0 */ 854: 86.endm 87 88#else 89#error "ERROR: I don't know how to probe your boards memory size?" 90#endif 91 92/*****************************************************************************/ 93 94/* 95 * Boards and platforms can do specific early hardware setup if 96 * they need to. Most don't need this, define away if not required. 97 */ 98#ifndef PLATFORM_SETUP 99#define PLATFORM_SETUP 100#endif 101 102/*****************************************************************************/ 103 104.global _start 105.global _rambase 106.global _ramvec 107.global _ramstart 108.global _ramend 109#if defined(CONFIG_UBOOT) 110.global _init_sp 111#endif 112 113/*****************************************************************************/ 114 115.data 116 117/* 118 * During startup we store away the RAM setup. These are not in the 119 * bss, since their values are determined and written before the bss 120 * has been cleared. 121 */ 122_rambase: 123.long 0 124_ramvec: 125.long 0 126_ramstart: 127.long 0 128_ramend: 129.long 0 130#if defined(CONFIG_UBOOT) 131_init_sp: 132.long 0 133#endif 134 135/*****************************************************************************/ 136 137__HEAD 138 139#ifdef CONFIG_MMU 140_start0: 141 jmp _start 142.global kernel_pg_dir 143.equ kernel_pg_dir,_start0 144.equ .,_start0+0x1000 145#endif 146 147/* 148 * This is the codes first entry point. This is where it all 149 * begins... 150 */ 151 152_start: 153 nop /* filler */ 154 movew #0x2700, %sr /* no interrupts */ 155 movel #CACHE_INIT,%d0 /* disable cache */ 156 movec %d0,%CACR 157 nop 158#if defined(CONFIG_UBOOT) 159 movel %sp,_init_sp /* save initial stack pointer */ 160#endif 161#ifdef CONFIG_MBAR 162 movel #CONFIG_MBAR+1,%d0 /* configured MBAR address */ 163 movec %d0,%MBAR /* set it */ 164#endif 165 166 /* 167 * Do any platform or board specific setup now. Most boards 168 * don't need anything. Those exceptions are define this in 169 * their board specific includes. 170 */ 171 PLATFORM_SETUP 172 173 /* 174 * Create basic memory configuration. Set VBR accordingly, 175 * and size memory. 176 */ 177 movel #CONFIG_VECTORBASE,%a7 178 movec %a7,%VBR /* set vectors addr */ 179 movel %a7,_ramvec 180 181 movel #CONFIG_RAMBASE,%a7 /* mark the base of RAM */ 182 movel %a7,_rambase 183 184 GET_MEM_SIZE /* macro code determines size */ 185 addl %a7,%d0 186 movel %d0,_ramend /* set end ram addr */ 187 188 /* 189 * Now that we know what the memory is, lets enable cache 190 * and get things moving. This is Coldfire CPU specific. Not 191 * all version cores have identical cache register setup. But 192 * it is very similar. Define the exact settings in the headers 193 * then the code here is the same for all. 194 */ 195 movel #ACR0_MODE,%d0 /* set RAM region for caching */ 196 movec %d0,%ACR0 197 movel #ACR1_MODE,%d0 /* anything else to cache? */ 198 movec %d0,%ACR1 199#ifdef ACR2_MODE 200 movel #ACR2_MODE,%d0 201 movec %d0,%ACR2 202 movel #ACR3_MODE,%d0 203 movec %d0,%ACR3 204#endif 205 movel #CACHE_MODE,%d0 /* enable cache */ 206 movec %d0,%CACR 207 nop 208 209#ifdef CONFIG_MMU 210 /* 211 * Identity mapping for the kernel region. 212 */ 213 movel #(MMUBASE+1),%d0 /* enable MMUBAR registers */ 214 movec %d0,%MMUBAR 215 movel #MMUOR_CA,%d0 /* clear TLB entries */ 216 movel %d0,MMUOR 217 movel #0,%d0 /* set ASID to 0 */ 218 movec %d0,%asid 219 220 movel #MMUCR_EN,%d0 /* Enable the identity map */ 221 movel %d0,MMUCR 222 nop /* sync i-pipeline */ 223 224 movel #_vstart,%a0 /* jump to "virtual" space */ 225 jmp %a0@ 226_vstart: 227#endif /* CONFIG_MMU */ 228 229#ifdef CONFIG_ROMFS_FS 230 /* 231 * Move ROM filesystem above bss :-) 232 */ 233 lea __bss_start,%a0 /* get start of bss */ 234 lea __bss_stop,%a1 /* set up destination */ 235 movel %a0,%a2 /* copy of bss start */ 236 237 movel 8(%a0),%d0 /* get size of ROMFS */ 238 addql #8,%d0 /* allow for rounding */ 239 andl #0xfffffffc, %d0 /* whole words */ 240 241 addl %d0,%a0 /* copy from end */ 242 addl %d0,%a1 /* copy from end */ 243 movel %a1,_ramstart /* set start of ram */ 244 245_copy_romfs: 246 movel -(%a0),%d0 /* copy dword */ 247 movel %d0,-(%a1) 248 cmpl %a0,%a2 /* check if at end */ 249 bne _copy_romfs 250 251#else /* CONFIG_ROMFS_FS */ 252 lea __bss_stop,%a1 253 movel %a1,_ramstart 254#endif /* CONFIG_ROMFS_FS */ 255 256 257 /* 258 * Zero out the bss region. 259 */ 260 lea __bss_start,%a0 /* get start of bss */ 261 lea __bss_stop,%a1 /* get end of bss */ 262 clrl %d0 /* set value */ 263_clear_bss: 264 movel %d0,(%a0)+ /* clear each word */ 265 cmpl %a0,%a1 /* check if at end */ 266 bne _clear_bss 267 268 /* 269 * Load the current task pointer and stack. 270 */ 271 lea init_thread_union,%a0 272 lea THREAD_SIZE(%a0),%sp 273 274#ifdef CONFIG_MMU 275.global m68k_cputype 276.global m68k_mmutype 277.global m68k_fputype 278.global m68k_machtype 279 movel #CPU_COLDFIRE,%d0 280 movel %d0,m68k_cputype /* Mark us as a ColdFire */ 281 movel #MMU_COLDFIRE,%d0 282 movel %d0,m68k_mmutype 283 movel #FPU_COLDFIRE,%d0 284 movel %d0,m68k_fputype 285 movel #MACH_M54XX,%d0 286 movel %d0,m68k_machtype /* Mark us as a 54xx machine */ 287 lea init_task,%a2 /* Set "current" init task */ 288#endif 289 290 /* 291 * Assembler start up done, start code proper. 292 */ 293 jsr start_kernel /* start Linux kernel */ 294 295_exit: 296 jmp _exit /* should never get here */ 297 298/*****************************************************************************/ 299