arch/sh/kernel/cpu/init.c

   1 /*
   2  * arch/sh/kernel/cpu/init.c
   3  *
   4  * CPU init code
   5  *
   6  * Copyright (C) 2002 - 2009  Paul Mundt
   7  * Copyright (C) 2003  Richard Curnow
   8  *
   9  * This file is subject to the terms and conditions of the GNU General Public
  10  * License.  See the file "COPYING" in the main directory of this archive
  11  * for more details.
  12  */
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/mm.h>
  16 #include <linux/log2.h>
  17 #include <asm/mmu_context.h>
  18 #include <asm/processor.h>
  19 #include <asm/uaccess.h>
  20 #include <asm/page.h>
  21 #include <asm/cacheflush.h>
  22 #include <asm/cache.h>
  23 #include <asm/elf.h>
  24 #include <asm/io.h>
  25 #include <asm/smp.h>
  26 #include <asm/sh_bios.h>
  27 #include <asm/setup.h>
  28
  29 #ifdef CONFIG_SH_FPU
  30 #define cpu_has_fpu     1
  31 #else
  32 #define cpu_has_fpu     0
  33 #endif
  34
  35 #ifdef CONFIG_SH_DSP
  36 #define cpu_has_dsp     1
  37 #else
  38 #define cpu_has_dsp     0
  39 #endif
  40
  41 /*
  42  * Generic wrapper for command line arguments to disable on-chip
  43  * peripherals (nofpu, nodsp, and so forth).
  44  */
  45 #define onchip_setup(x)                                 \
  46 static int x##_disabled = !cpu_has_##x;                 \
  47                                                         \
  48 static int x##_setup(char *opts)                        \
  49 {                                                       \
  50         x##_disabled = 1;                               \
  51         return 1;                                       \
  52 }                                                       \
  53 __setup("no" __stringify(x), x##_setup);
  54
  55 onchip_setup(fpu);
  56 onchip_setup(dsp);
  57
  58 #ifdef CONFIG_SPECULATIVE_EXECUTION
  59 #define CPUOPM          0xff2f0000
  60 #define CPUOPM_RABD     (1 << 5)
  61
  62 static void speculative_execution_init(void)
  63 {
  64         /* Clear RABD */
  65         __raw_writel(__raw_readl(CPUOPM) & ~CPUOPM_RABD, CPUOPM);
  66
  67         /* Flush the update */
  68         (void)__raw_readl(CPUOPM);
  69         ctrl_barrier();
  70 }
  71 #else
  72 #define speculative_execution_init()    do { } while (0)
  73 #endif
  74
  75 #ifdef CONFIG_CPU_SH4A
  76 #define EXPMASK                 0xff2f0004
  77 #define EXPMASK_RTEDS           (1 << 0)
  78 #define EXPMASK_BRDSSLP         (1 << 1)
  79 #define EXPMASK_MMCAW           (1 << 4)
  80
  81 static void expmask_init(void)
  82 {
  83         unsigned long expmask = __raw_readl(EXPMASK);
  84
  85         /*
  86          * Future proofing.
  87          *
  88          * Disable support for slottable sleep instruction, non-nop
  89          * instructions in the rte delay slot, and associative writes to
  90          * the memory-mapped cache array.
  91          */
  92         expmask &= ~(EXPMASK_RTEDS | EXPMASK_BRDSSLP | EXPMASK_MMCAW);
  93
  94         __raw_writel(expmask, EXPMASK);
  95         ctrl_barrier();
  96 }
  97 #else
  98 #define expmask_init()  do { } while (0)
  99 #endif
 100
 101 /* 2nd-level cache init */
 102 void __attribute__ ((weak)) l2_cache_init(void)
 103 {
 104 }
 105
 106 /*
 107  * Generic first-level cache init
 108  */
 109 #ifdef CONFIG_SUPERH32
 110 static void cache_init(void)
 111 {
 112         unsigned long ccr, flags;
 113
 114         jump_to_uncached();
 115         ccr = __raw_readl(CCR);
 116
 117         /*
 118          * At this point we don't know whether the cache is enabled or not - a
 119          * bootloader may have enabled it.  There are at least 2 things that
 120          * could be dirty in the cache at this point:
 121          * 1. kernel command line set up by boot loader
 122          * 2. spilled registers from the prolog of this function
 123          * => before re-initialising the cache, we must do a purge of the whole
 124          * cache out to memory for safety.  As long as nothing is spilled
 125          * during the loop to lines that have already been done, this is safe.
 126          * - RPC
 127          */
 128         if (ccr & CCR_CACHE_ENABLE) {
 129                 unsigned long ways, waysize, addrstart;
 130
 131                 waysize = current_cpu_data.dcache.sets;
 132
 133 #ifdef CCR_CACHE_ORA
 134                 /*
 135                  * If the OC is already in RAM mode, we only have
 136                  * half of the entries to flush..
 137                  */
 138                 if (ccr & CCR_CACHE_ORA)
 139                         waysize >>= 1;
 140 #endif
 141
 142                 waysize <<= current_cpu_data.dcache.entry_shift;
 143
 144 #ifdef CCR_CACHE_EMODE
 145                 /* If EMODE is not set, we only have 1 way to flush. */
 146                 if (!(ccr & CCR_CACHE_EMODE))
 147                         ways = 1;
 148                 else
 149 #endif
 150                         ways = current_cpu_data.dcache.ways;
 151
 152                 addrstart = CACHE_OC_ADDRESS_ARRAY;
 153                 do {
 154                         unsigned long addr;
 155
 156                         for (addr = addrstart;
 157                              addr < addrstart + waysize;
 158                              addr += current_cpu_data.dcache.linesz)
 159                                 __raw_writel(0, addr);
 160
 161                         addrstart += current_cpu_data.dcache.way_incr;
 162                 } while (--ways);
 163         }
 164
 165         /*
 166          * Default CCR values .. enable the caches
 167          * and invalidate them immediately..
 168          */
 169         flags = CCR_CACHE_ENABLE | CCR_CACHE_INVALIDATE;
 170
 171 #ifdef CCR_CACHE_EMODE
 172         /* Force EMODE if possible */
 173         if (current_cpu_data.dcache.ways > 1)
 174                 flags |= CCR_CACHE_EMODE;
 175         else
 176                 flags &= ~CCR_CACHE_EMODE;
 177 #endif
 178
 179 #if defined(CONFIG_CACHE_WRITETHROUGH)
 180         /* Write-through */
 181         flags |= CCR_CACHE_WT;
 182 #elif defined(CONFIG_CACHE_WRITEBACK)
 183         /* Write-back */
 184         flags |= CCR_CACHE_CB;
 185 #else
 186         /* Off */
 187         flags &= ~CCR_CACHE_ENABLE;
 188 #endif
 189
 190         l2_cache_init();
 191
 192         __raw_writel(flags, CCR);
 193         back_to_cached();
 194 }
 195 #else
 196 #define cache_init()    do { } while (0)
 197 #endif
 198
 199 #define CSHAPE(totalsize, linesize, assoc) \
 200         ((totalsize & ~0xff) | (linesize << 4) | assoc)
 201
 202 #define CACHE_DESC_SHAPE(desc)  \
 203         CSHAPE((desc).way_size * (desc).ways, ilog2((desc).linesz), (desc).ways)
 204
 205 static void detect_cache_shape(void)
 206 {
 207         l1d_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.dcache);
 208
 209         if (current_cpu_data.dcache.flags & SH_CACHE_COMBINED)
 210                 l1i_cache_shape = l1d_cache_shape;
 211         else
 212                 l1i_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.icache);
 213
 214         if (current_cpu_data.flags & CPU_HAS_L2_CACHE)
 215                 l2_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.scache);
 216         else
 217                 l2_cache_shape = -1; /* No S-cache */
 218 }
 219
 220 static void fpu_init(void)
 221 {
 222         /* Disable the FPU */
 223         if (fpu_disabled && (current_cpu_data.flags & CPU_HAS_FPU)) {
 224                 printk("FPU Disabled\n");
 225                 current_cpu_data.flags &= ~CPU_HAS_FPU;
 226         }
 227
 228         disable_fpu();
 229         clear_used_math();
 230 }
 231
 232 #ifdef CONFIG_SH_DSP
 233 static void release_dsp(void)
 234 {
 235         unsigned long sr;
 236
 237         /* Clear SR.DSP bit */
 238         __asm__ __volatile__ (
 239                 "stc\tsr, %0\n\t"
 240                 "and\t%1, %0\n\t"
 241                 "ldc\t%0, sr\n\t"
 242                 : "=&r" (sr)
 243                 : "r" (~SR_DSP)
 244         );
 245 }
 246
 247 static void dsp_init(void)
 248 {
 249         unsigned long sr;
 250
 251         /*
 252          * Set the SR.DSP bit, wait for one instruction, and then read
 253          * back the SR value.
 254          */
 255         __asm__ __volatile__ (
 256                 "stc\tsr, %0\n\t"
 257                 "or\t%1, %0\n\t"
 258                 "ldc\t%0, sr\n\t"
 259                 "nop\n\t"
 260                 "stc\tsr, %0\n\t"
 261                 : "=&r" (sr)
 262                 : "r" (SR_DSP)
 263         );
 264
 265         /* If the DSP bit is still set, this CPU has a DSP */
 266         if (sr & SR_DSP)
 267                 current_cpu_data.flags |= CPU_HAS_DSP;
 268
 269         /* Disable the DSP */
 270         if (dsp_disabled && (current_cpu_data.flags & CPU_HAS_DSP)) {
 271                 printk("DSP Disabled\n");
 272                 current_cpu_data.flags &= ~CPU_HAS_DSP;
 273         }
 274
 275         /* Now that we've determined the DSP status, clear the DSP bit. */
 276         release_dsp();
 277 }
 278 #else
 279 static inline void dsp_init(void) { }
 280 #endif /* CONFIG_SH_DSP */
 281
 282 /**
 283  * cpu_init
 284  *
 285  * This is our initial entry point for each CPU, and is invoked on the
 286  * boot CPU prior to calling start_kernel(). For SMP, a combination of
 287  * this and start_secondary() will bring up each processor to a ready
 288  * state prior to hand forking the idle loop.
 289  *
 290  * We do all of the basic processor init here, including setting up
 291  * the caches, FPU, DSP, etc. By the time start_kernel() is hit (and
 292  * subsequently platform_setup()) things like determining the CPU
 293  * subtype and initial configuration will all be done.
 294  *
 295  * Each processor family is still responsible for doing its own probing
 296  * and cache configuration in cpu_probe().
 297  */
 298 asmlinkage void cpu_init(void)
 299 {
 300         current_thread_info()->cpu = hard_smp_processor_id();
 301
 302         /* First, probe the CPU */
 303         cpu_probe();
 304
 305         if (current_cpu_data.type == CPU_SH_NONE)
 306                 panic("Unknown CPU");
 307
 308         /* First setup the rest of the I-cache info */
 309         current_cpu_data.icache.entry_mask = current_cpu_data.icache.way_incr -
 310                                       current_cpu_data.icache.linesz;
 311
 312         current_cpu_data.icache.way_size = current_cpu_data.icache.sets *
 313                                     current_cpu_data.icache.linesz;
 314
 315         /* And the D-cache too */
 316         current_cpu_data.dcache.entry_mask = current_cpu_data.dcache.way_incr -
 317                                       current_cpu_data.dcache.linesz;
 318
 319         current_cpu_data.dcache.way_size = current_cpu_data.dcache.sets *
 320                                     current_cpu_data.dcache.linesz;
 321
 322         /* Init the cache */
 323         cache_init();
 324
 325         if (raw_smp_processor_id() == 0) {
 326                 shm_align_mask = max_t(unsigned long,
 327                                        current_cpu_data.dcache.way_size - 1,
 328                                        PAGE_SIZE - 1);
 329
 330                 /* Boot CPU sets the cache shape */
 331                 detect_cache_shape();
 332         }
 333
 334         fpu_init();
 335         dsp_init();
 336
 337         /*
 338          * Initialize the per-CPU ASID cache very early, since the
 339          * TLB flushing routines depend on this being setup.
 340          */
 341         current_cpu_data.asid_cache = NO_CONTEXT;
 342
 343         current_cpu_data.phys_bits = __in_29bit_mode() ? 29 : 32;
 344
 345         speculative_execution_init();
 346         expmask_init();
 347
 348         /* Do the rest of the boot processor setup */
 349         if (raw_smp_processor_id() == 0) {
 350                 /* Save off the BIOS VBR, if there is one */
 351                 sh_bios_vbr_init();
 352
 353                 /*
 354                  * Setup VBR for boot CPU. Secondary CPUs do this through
 355                  * start_secondary().
 356                  */
 357                 per_cpu_trap_init();
 358
 359                 /*
 360                  * Boot processor to setup the FP and extended state
 361                  * context info.
 362                  */
 363                 init_thread_xstate();
 364         }
 365 }