root/arch/sh/kernel/cpu/init.c

DEFINITIONS

1. speculative_execution_init
2. expmask_init
3. l2_cache_init
4. cache_init
5. detect_cache_shape
6. fpu_init
7. release_dsp
8. dsp_init
9. dsp_init
10. cpu_init

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * arch/sh/kernel/cpu/init.c
   4  *
   5  * CPU init code
   6  *
   7  * Copyright (C) 2002 - 2009  Paul Mundt
   8  * Copyright (C) 2003  Richard Curnow
   9  */
  10 #include <linux/init.h>
  11 #include <linux/kernel.h>
  12 #include <linux/mm.h>
  13 #include <linux/log2.h>
  14 #include <asm/mmu_context.h>
  15 #include <asm/processor.h>
  16 #include <linux/uaccess.h>
  17 #include <asm/page.h>
  18 #include <asm/cacheflush.h>
  19 #include <asm/cache.h>
  20 #include <asm/elf.h>
  21 #include <asm/io.h>
  22 #include <asm/smp.h>
  23 #include <asm/sh_bios.h>
  24 #include <asm/setup.h>
  25 
  26 #ifdef CONFIG_SH_FPU
  27 #define cpu_has_fpu     1
  28 #else
  29 #define cpu_has_fpu     0
  30 #endif
  31 
  32 #ifdef CONFIG_SH_DSP
  33 #define cpu_has_dsp     1
  34 #else
  35 #define cpu_has_dsp     0
  36 #endif
  37 
  38 /*
  39  * Generic wrapper for command line arguments to disable on-chip
  40  * peripherals (nofpu, nodsp, and so forth).
  41  */
  42 #define onchip_setup(x)                                 \
  43 static int x##_disabled = !cpu_has_##x;                 \
  44                                                         \
  45 static int x##_setup(char *opts)                        \
  46 {                                                       \
  47         x##_disabled = 1;                               \
  48         return 1;                                       \
  49 }                                                       \
  50 __setup("no" __stringify(x), x##_setup);
  51 
  52 onchip_setup(fpu);
  53 onchip_setup(dsp);
  54 
  55 #ifdef CONFIG_SPECULATIVE_EXECUTION
  56 #define CPUOPM          0xff2f0000
  57 #define CPUOPM_RABD     (1 << 5)
  58 
  59 static void speculative_execution_init(void)
  60 {
  61         /* Clear RABD */
  62         __raw_writel(__raw_readl(CPUOPM) & ~CPUOPM_RABD, CPUOPM);
  63 
  64         /* Flush the update */
  65         (void)__raw_readl(CPUOPM);
  66         ctrl_barrier();
  67 }
  68 #else
  69 #define speculative_execution_init()    do { } while (0)
  70 #endif
  71 
  72 #ifdef CONFIG_CPU_SH4A
  73 #define EXPMASK                 0xff2f0004
  74 #define EXPMASK_RTEDS           (1 << 0)
  75 #define EXPMASK_BRDSSLP         (1 << 1)
  76 #define EXPMASK_MMCAW           (1 << 4)
  77 
  78 static void expmask_init(void)
  79 {
  80         unsigned long expmask = __raw_readl(EXPMASK);
  81 
  82         /*
  83          * Future proofing.
  84          *
  85          * Disable support for slottable sleep instruction, non-nop
  86          * instructions in the rte delay slot, and associative writes to
  87          * the memory-mapped cache array.
  88          */
  89         expmask &= ~(EXPMASK_RTEDS | EXPMASK_BRDSSLP | EXPMASK_MMCAW);
  90 
  91         __raw_writel(expmask, EXPMASK);
  92         ctrl_barrier();
  93 }
  94 #else
  95 #define expmask_init()  do { } while (0)
  96 #endif
  97 
  98 /* 2nd-level cache init */
  99 void __attribute__ ((weak)) l2_cache_init(void)
 100 {
 101 }
 102 
 103 /*
 104  * Generic first-level cache init
 105  */
 106 #if defined(CONFIG_SUPERH32) && !defined(CONFIG_CPU_J2)
 107 static void cache_init(void)
 108 {
 109         unsigned long ccr, flags;
 110 
 111         jump_to_uncached();
 112         ccr = __raw_readl(SH_CCR);
 113 
 114         /*
 115          * At this point we don't know whether the cache is enabled or not - a
 116          * bootloader may have enabled it.  There are at least 2 things that
 117          * could be dirty in the cache at this point:
 118          * 1. kernel command line set up by boot loader
 119          * 2. spilled registers from the prolog of this function
 120          * => before re-initialising the cache, we must do a purge of the whole
 121          * cache out to memory for safety.  As long as nothing is spilled
 122          * during the loop to lines that have already been done, this is safe.
 123          * - RPC
 124          */
 125         if (ccr & CCR_CACHE_ENABLE) {
 126                 unsigned long ways, waysize, addrstart;
 127 
 128                 waysize = current_cpu_data.dcache.sets;
 129 
 130 #ifdef CCR_CACHE_ORA
 131                 /*
 132                  * If the OC is already in RAM mode, we only have
 133                  * half of the entries to flush..
 134                  */
 135                 if (ccr & CCR_CACHE_ORA)
 136                         waysize >>= 1;
 137 #endif
 138 
 139                 waysize <<= current_cpu_data.dcache.entry_shift;
 140 
 141 #ifdef CCR_CACHE_EMODE
 142                 /* If EMODE is not set, we only have 1 way to flush. */
 143                 if (!(ccr & CCR_CACHE_EMODE))
 144                         ways = 1;
 145                 else
 146 #endif
 147                         ways = current_cpu_data.dcache.ways;
 148 
 149                 addrstart = CACHE_OC_ADDRESS_ARRAY;
 150                 do {
 151                         unsigned long addr;
 152 
 153                         for (addr = addrstart;
 154                              addr < addrstart + waysize;
 155                              addr += current_cpu_data.dcache.linesz)
 156                                 __raw_writel(0, addr);
 157 
 158                         addrstart += current_cpu_data.dcache.way_incr;
 159                 } while (--ways);
 160         }
 161 
 162         /*
 163          * Default CCR values .. enable the caches
 164          * and invalidate them immediately..
 165          */
 166         flags = CCR_CACHE_ENABLE | CCR_CACHE_INVALIDATE;
 167 
 168 #ifdef CCR_CACHE_EMODE
 169         /* Force EMODE if possible */
 170         if (current_cpu_data.dcache.ways > 1)
 171                 flags |= CCR_CACHE_EMODE;
 172         else
 173                 flags &= ~CCR_CACHE_EMODE;
 174 #endif
 175 
 176 #if defined(CONFIG_CACHE_WRITETHROUGH)
 177         /* Write-through */
 178         flags |= CCR_CACHE_WT;
 179 #elif defined(CONFIG_CACHE_WRITEBACK)
 180         /* Write-back */
 181         flags |= CCR_CACHE_CB;
 182 #else
 183         /* Off */
 184         flags &= ~CCR_CACHE_ENABLE;
 185 #endif
 186 
 187         l2_cache_init();
 188 
 189         __raw_writel(flags, SH_CCR);
 190         back_to_cached();
 191 }
 192 #else
 193 #define cache_init()    do { } while (0)
 194 #endif
 195 
 196 #define CSHAPE(totalsize, linesize, assoc) \
 197         ((totalsize & ~0xff) | (linesize << 4) | assoc)
 198 
 199 #define CACHE_DESC_SHAPE(desc)  \
 200         CSHAPE((desc).way_size * (desc).ways, ilog2((desc).linesz), (desc).ways)
 201 
 202 static void detect_cache_shape(void)
 203 {
 204         l1d_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.dcache);
 205 
 206         if (current_cpu_data.dcache.flags & SH_CACHE_COMBINED)
 207                 l1i_cache_shape = l1d_cache_shape;
 208         else
 209                 l1i_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.icache);
 210 
 211         if (current_cpu_data.flags & CPU_HAS_L2_CACHE)
 212                 l2_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.scache);
 213         else
 214                 l2_cache_shape = -1; /* No S-cache */
 215 }
 216 
 217 static void fpu_init(void)
 218 {
 219         /* Disable the FPU */
 220         if (fpu_disabled && (current_cpu_data.flags & CPU_HAS_FPU)) {
 221                 printk("FPU Disabled\n");
 222                 current_cpu_data.flags &= ~CPU_HAS_FPU;
 223         }
 224 
 225         disable_fpu();
 226         clear_used_math();
 227 }
 228 
 229 #ifdef CONFIG_SH_DSP
 230 static void release_dsp(void)
 231 {
 232         unsigned long sr;
 233 
 234         /* Clear SR.DSP bit */
 235         __asm__ __volatile__ (
 236                 "stc\tsr, %0\n\t"
 237                 "and\t%1, %0\n\t"
 238                 "ldc\t%0, sr\n\t"
 239                 : "=&r" (sr)
 240                 : "r" (~SR_DSP)
 241         );
 242 }
 243 
 244 static void dsp_init(void)
 245 {
 246         unsigned long sr;
 247 
 248         /*
 249          * Set the SR.DSP bit, wait for one instruction, and then read
 250          * back the SR value.
 251          */
 252         __asm__ __volatile__ (
 253                 "stc\tsr, %0\n\t"
 254                 "or\t%1, %0\n\t"
 255                 "ldc\t%0, sr\n\t"
 256                 "nop\n\t"
 257                 "stc\tsr, %0\n\t"
 258                 : "=&r" (sr)
 259                 : "r" (SR_DSP)
 260         );
 261 
 262         /* If the DSP bit is still set, this CPU has a DSP */
 263         if (sr & SR_DSP)
 264                 current_cpu_data.flags |= CPU_HAS_DSP;
 265 
 266         /* Disable the DSP */
 267         if (dsp_disabled && (current_cpu_data.flags & CPU_HAS_DSP)) {
 268                 printk("DSP Disabled\n");
 269                 current_cpu_data.flags &= ~CPU_HAS_DSP;
 270         }
 271 
 272         /* Now that we've determined the DSP status, clear the DSP bit. */
 273         release_dsp();
 274 }
 275 #else
 276 static inline void dsp_init(void) { }
 277 #endif /* CONFIG_SH_DSP */
 278 
 279 /**
 280  * cpu_init
 281  *
 282  * This is our initial entry point for each CPU, and is invoked on the
 283  * boot CPU prior to calling start_kernel(). For SMP, a combination of
 284  * this and start_secondary() will bring up each processor to a ready
 285  * state prior to hand forking the idle loop.
 286  *
 287  * We do all of the basic processor init here, including setting up
 288  * the caches, FPU, DSP, etc. By the time start_kernel() is hit (and
 289  * subsequently platform_setup()) things like determining the CPU
 290  * subtype and initial configuration will all be done.
 291  *
 292  * Each processor family is still responsible for doing its own probing
 293  * and cache configuration in cpu_probe().
 294  */
 295 asmlinkage void cpu_init(void)
 296 {
 297         current_thread_info()->cpu = hard_smp_processor_id();
 298 
 299         /* First, probe the CPU */
 300         cpu_probe();
 301 
 302         if (current_cpu_data.type == CPU_SH_NONE)
 303                 panic("Unknown CPU");
 304 
 305         /* First setup the rest of the I-cache info */
 306         current_cpu_data.icache.entry_mask = current_cpu_data.icache.way_incr -
 307                                       current_cpu_data.icache.linesz;
 308 
 309         current_cpu_data.icache.way_size = current_cpu_data.icache.sets *
 310                                     current_cpu_data.icache.linesz;
 311 
 312         /* And the D-cache too */
 313         current_cpu_data.dcache.entry_mask = current_cpu_data.dcache.way_incr -
 314                                       current_cpu_data.dcache.linesz;
 315 
 316         current_cpu_data.dcache.way_size = current_cpu_data.dcache.sets *
 317                                     current_cpu_data.dcache.linesz;
 318 
 319         /* Init the cache */
 320         cache_init();
 321 
 322         if (raw_smp_processor_id() == 0) {
 323 #ifdef CONFIG_MMU
 324                 shm_align_mask = max_t(unsigned long,
 325                                        current_cpu_data.dcache.way_size - 1,
 326                                        PAGE_SIZE - 1);
 327 #else
 328                 shm_align_mask = PAGE_SIZE - 1;
 329 #endif
 330 
 331                 /* Boot CPU sets the cache shape */
 332                 detect_cache_shape();
 333         }
 334 
 335         fpu_init();
 336         dsp_init();
 337 
 338         /*
 339          * Initialize the per-CPU ASID cache very early, since the
 340          * TLB flushing routines depend on this being setup.
 341          */
 342         current_cpu_data.asid_cache = NO_CONTEXT;
 343 
 344         current_cpu_data.phys_bits = __in_29bit_mode() ? 29 : 32;
 345 
 346         speculative_execution_init();
 347         expmask_init();
 348 
 349         /* Do the rest of the boot processor setup */
 350         if (raw_smp_processor_id() == 0) {
 351                 /* Save off the BIOS VBR, if there is one */
 352                 sh_bios_vbr_init();
 353 
 354                 /*
 355                  * Setup VBR for boot CPU. Secondary CPUs do this through
 356                  * start_secondary().
 357                  */
 358                 per_cpu_trap_init();
 359 
 360                 /*
 361                  * Boot processor to setup the FP and extended state
 362                  * context info.
 363                  */
 364                 init_thread_xstate();
 365         }
 366 }