arch/arc/kernel/setup.c

   1 /*
   2  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/seq_file.h>
  10 #include <linux/fs.h>
  11 #include <linux/delay.h>
  12 #include <linux/root_dev.h>
  13 #include <linux/clk.h>
  14 #include <linux/clk-provider.h>
  15 #include <linux/clocksource.h>
  16 #include <linux/console.h>
  17 #include <linux/module.h>
  18 #include <linux/cpu.h>
  19 #include <linux/of_fdt.h>
  20 #include <linux/of.h>
  21 #include <linux/cache.h>
  22 #include <asm/sections.h>
  23 #include <asm/arcregs.h>
  24 #include <asm/tlb.h>
  25 #include <asm/setup.h>
  26 #include <asm/page.h>
  27 #include <asm/irq.h>
  28 #include <asm/unwind.h>
  29 #include <asm/mach_desc.h>
  30 #include <asm/smp.h>
  31
  32 #define FIX_PTR(x)  __asm__ __volatile__(";" : "+r"(x))
  33
  34 unsigned int intr_to_DE_cnt;
  35
  36 /* Part of U-boot ABI: see head.S */
  37 int __initdata uboot_tag;
  38 char __initdata *uboot_arg;
  39
  40 const struct machine_desc *machine_desc;
  41
  42 struct task_struct *_current_task[NR_CPUS];     /* For stack switching */
  43
  44 struct cpuinfo_arc cpuinfo_arc700[NR_CPUS];
  45
  46 static const struct id_to_str arc_cpu_rel[] = {
  47 #ifdef CONFIG_ISA_ARCOMPACT
  48         { 0x34, "R4.10"},
  49         { 0x35, "R4.11"},
  50 #else
  51         { 0x51, "R2.0" },
  52         { 0x52, "R2.1" },
  53         { 0x53, "R3.0" },
  54         { 0x54, "R4.0" },
  55 #endif
  56         { 0x00, NULL   }
  57 };
  58
  59 static const struct id_to_str arc_cpu_nm[] = {
  60 #ifdef CONFIG_ISA_ARCOMPACT
  61         { 0x20, "ARC 600"   },
  62         { 0x30, "ARC 770"   },  /* 750 identified seperately */
  63 #else
  64         { 0x40, "ARC EM"  },
  65         { 0x50, "ARC HS38"  },
  66         { 0x54, "ARC HS48"  },
  67 #endif
  68         { 0x00, "Unknown"   }
  69 };
  70
  71 static void read_decode_ccm_bcr(struct cpuinfo_arc *cpu)
  72 {
  73         if (is_isa_arcompact()) {
  74                 struct bcr_iccm_arcompact iccm;
  75                 struct bcr_dccm_arcompact dccm;
  76
  77                 READ_BCR(ARC_REG_ICCM_BUILD, iccm);
  78                 if (iccm.ver) {
  79                         cpu->iccm.sz = 4096 << iccm.sz; /* 8K to 512K */
  80                         cpu->iccm.base_addr = iccm.base << 16;
  81                 }
  82
  83                 READ_BCR(ARC_REG_DCCM_BUILD, dccm);
  84                 if (dccm.ver) {
  85                         unsigned long base;
  86                         cpu->dccm.sz = 2048 << dccm.sz; /* 2K to 256K */
  87
  88                         base = read_aux_reg(ARC_REG_DCCM_BASE_BUILD);
  89                         cpu->dccm.base_addr = base & ~0xF;
  90                 }
  91         } else {
  92                 struct bcr_iccm_arcv2 iccm;
  93                 struct bcr_dccm_arcv2 dccm;
  94                 unsigned long region;
  95
  96                 READ_BCR(ARC_REG_ICCM_BUILD, iccm);
  97                 if (iccm.ver) {
  98                         cpu->iccm.sz = 256 << iccm.sz00;        /* 512B to 16M */
  99                         if (iccm.sz00 == 0xF && iccm.sz01 > 0)
 100                                 cpu->iccm.sz <<= iccm.sz01;
 101
 102                         region = read_aux_reg(ARC_REG_AUX_ICCM);
 103                         cpu->iccm.base_addr = region & 0xF0000000;
 104                 }
 105
 106                 READ_BCR(ARC_REG_DCCM_BUILD, dccm);
 107                 if (dccm.ver) {
 108                         cpu->dccm.sz = 256 << dccm.sz0;
 109                         if (dccm.sz0 == 0xF && dccm.sz1 > 0)
 110                                 cpu->dccm.sz <<= dccm.sz1;
 111
 112                         region = read_aux_reg(ARC_REG_AUX_DCCM);
 113                         cpu->dccm.base_addr = region & 0xF0000000;
 114                 }
 115         }
 116 }
 117
 118 static void read_arc_build_cfg_regs(void)
 119 {
 120         struct bcr_timer timer;
 121         struct bcr_generic bcr;
 122         struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
 123         const struct id_to_str *tbl;
 124         struct bcr_isa_arcv2 isa;
 125
 126         FIX_PTR(cpu);
 127
 128         READ_BCR(AUX_IDENTITY, cpu->core);
 129
 130         for (tbl = &arc_cpu_rel[0]; tbl->id != 0; tbl++) {
 131                 if (cpu->core.family == tbl->id) {
 132                         cpu->details = tbl->str;
 133                         break;
 134                 }
 135         }
 136
 137         for (tbl = &arc_cpu_nm[0]; tbl->id != 0; tbl++) {
 138                 if ((cpu->core.family & 0xF4) == tbl->id)
 139                         break;
 140         }
 141         cpu->name = tbl->str;
 142
 143         READ_BCR(ARC_REG_TIMERS_BCR, timer);
 144         cpu->extn.timer0 = timer.t0;
 145         cpu->extn.timer1 = timer.t1;
 146         cpu->extn.rtc = timer.rtc;
 147
 148         cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);
 149
 150         READ_BCR(ARC_REG_MUL_BCR, cpu->extn_mpy);
 151
 152         cpu->extn.norm = read_aux_reg(ARC_REG_NORM_BCR) > 1 ? 1 : 0; /* 2,3 */
 153         cpu->extn.barrel = read_aux_reg(ARC_REG_BARREL_BCR) > 1 ? 1 : 0; /* 2,3 */
 154         cpu->extn.swap = read_aux_reg(ARC_REG_SWAP_BCR) ? 1 : 0;        /* 1,3 */
 155         cpu->extn.crc = read_aux_reg(ARC_REG_CRC_BCR) ? 1 : 0;
 156         cpu->extn.minmax = read_aux_reg(ARC_REG_MIXMAX_BCR) > 1 ? 1 : 0; /* 2 */
 157         cpu->extn.swape = (cpu->core.family >= 0x34) ? 1 :
 158                                 IS_ENABLED(CONFIG_ARC_HAS_SWAPE);
 159
 160         READ_BCR(ARC_REG_XY_MEM_BCR, cpu->extn_xymem);
 161
 162         /* Read CCM BCRs for boot reporting even if not enabled in Kconfig */
 163         read_decode_ccm_bcr(cpu);
 164
 165         read_decode_mmu_bcr();
 166         read_decode_cache_bcr();
 167
 168         if (is_isa_arcompact()) {
 169                 struct bcr_fp_arcompact sp, dp;
 170                 struct bcr_bpu_arcompact bpu;
 171
 172                 READ_BCR(ARC_REG_FP_BCR, sp);
 173                 READ_BCR(ARC_REG_DPFP_BCR, dp);
 174                 cpu->extn.fpu_sp = sp.ver ? 1 : 0;
 175                 cpu->extn.fpu_dp = dp.ver ? 1 : 0;
 176
 177                 READ_BCR(ARC_REG_BPU_BCR, bpu);
 178                 cpu->bpu.ver = bpu.ver;
 179                 cpu->bpu.full = bpu.fam ? 1 : 0;
 180                 if (bpu.ent) {
 181                         cpu->bpu.num_cache = 256 << (bpu.ent - 1);
 182                         cpu->bpu.num_pred = 256 << (bpu.ent - 1);
 183                 }
 184         } else {
 185                 struct bcr_fp_arcv2 spdp;
 186                 struct bcr_bpu_arcv2 bpu;
 187
 188                 READ_BCR(ARC_REG_FP_V2_BCR, spdp);
 189                 cpu->extn.fpu_sp = spdp.sp ? 1 : 0;
 190                 cpu->extn.fpu_dp = spdp.dp ? 1 : 0;
 191
 192                 READ_BCR(ARC_REG_BPU_BCR, bpu);
 193                 cpu->bpu.ver = bpu.ver;
 194                 cpu->bpu.full = bpu.ft;
 195                 cpu->bpu.num_cache = 256 << bpu.bce;
 196                 cpu->bpu.num_pred = 2048 << bpu.pte;
 197
 198                 if (cpu->core.family >= 0x54) {
 199                         unsigned int exec_ctrl;
 200
 201                         READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
 202                         cpu->extn.dual_enb = !(exec_ctrl & 1);
 203
 204                         /* dual issue always present for this core */
 205                         cpu->extn.dual = 1;
 206                 }
 207         }
 208
 209         READ_BCR(ARC_REG_AP_BCR, bcr);
 210         cpu->extn.ap = bcr.ver ? 1 : 0;
 211
 212         READ_BCR(ARC_REG_SMART_BCR, bcr);
 213         cpu->extn.smart = bcr.ver ? 1 : 0;
 214
 215         READ_BCR(ARC_REG_RTT_BCR, bcr);
 216         cpu->extn.rtt = bcr.ver ? 1 : 0;
 217
 218         cpu->extn.debug = cpu->extn.ap | cpu->extn.smart | cpu->extn.rtt;
 219
 220         READ_BCR(ARC_REG_ISA_CFG_BCR, isa);
 221
 222         /* some hacks for lack of feature BCR info in old ARC700 cores */
 223         if (is_isa_arcompact()) {
 224                 if (!isa.ver)   /* ISA BCR absent, use Kconfig info */
 225                         cpu->isa.atomic = IS_ENABLED(CONFIG_ARC_HAS_LLSC);
 226                 else {
 227                         /* ARC700_BUILD only has 2 bits of isa info */
 228                         struct bcr_generic bcr = *(struct bcr_generic *)&isa;
 229                         cpu->isa.atomic = bcr.info & 1;
 230                 }
 231
 232                 cpu->isa.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
 233
 234                  /* there's no direct way to distinguish 750 vs. 770 */
 235                 if (unlikely(cpu->core.family < 0x34 || cpu->mmu.ver < 3))
 236                         cpu->name = "ARC750";
 237         } else {
 238                 cpu->isa = isa;
 239         }
 240 }
 241
 242 static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
 243 {
 244         struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
 245         struct bcr_identity *core = &cpu->core;
 246         int i, n = 0;
 247
 248         FIX_PTR(cpu);
 249
 250         n += scnprintf(buf + n, len - n,
 251                        "\nIDENTITY\t: ARCVER [%#02x] ARCNUM [%#02x] CHIPID [%#4x]\n",
 252                        core->family, core->cpu_id, core->chip_id);
 253
 254         n += scnprintf(buf + n, len - n, "processor [%d]\t: %s %s (%s ISA) %s%s%s\n",
 255                        cpu_id, cpu->name, cpu->details,
 256                        is_isa_arcompact() ? "ARCompact" : "ARCv2",
 257                        IS_AVAIL1(cpu->isa.be, "[Big-Endian]"),
 258                        IS_AVAIL3(cpu->extn.dual, cpu->extn.dual_enb, " Dual-Issue "));
 259
 260         n += scnprintf(buf + n, len - n, "Timers\t\t: %s%s%s%s%s%s\nISA Extn\t: ",
 261                        IS_AVAIL1(cpu->extn.timer0, "Timer0 "),
 262                        IS_AVAIL1(cpu->extn.timer1, "Timer1 "),
 263                        IS_AVAIL2(cpu->extn.rtc, "RTC [UP 64-bit] ", CONFIG_ARC_TIMERS_64BIT),
 264                        IS_AVAIL2(cpu->extn.gfrc, "GFRC [SMP 64-bit] ", CONFIG_ARC_TIMERS_64BIT));
 265
 266         n += i = scnprintf(buf + n, len - n, "%s%s%s%s%s",
 267                            IS_AVAIL2(cpu->isa.atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
 268                            IS_AVAIL2(cpu->isa.ldd, "ll64 ", CONFIG_ARC_HAS_LL64),
 269                            IS_AVAIL1(cpu->isa.unalign, "unalign (not used)"));
 270
 271         if (i)
 272                 n += scnprintf(buf + n, len - n, "\n\t\t: ");
 273
 274         if (cpu->extn_mpy.ver) {
 275                 if (cpu->extn_mpy.ver <= 0x2) { /* ARCompact */
 276                         n += scnprintf(buf + n, len - n, "mpy ");
 277                 } else {
 278                         int opt = 2;    /* stock MPY/MPYH */
 279
 280                         if (cpu->extn_mpy.dsp)  /* OPT 7-9 */
 281                                 opt = cpu->extn_mpy.dsp + 6;
 282
 283                         n += scnprintf(buf + n, len - n, "mpy[opt %d] ", opt);
 284                 }
 285         }
 286
 287         n += scnprintf(buf + n, len - n, "%s%s%s%s%s%s%s%s\n",
 288                        IS_AVAIL1(cpu->isa.div_rem, "div_rem "),
 289                        IS_AVAIL1(cpu->extn.norm, "norm "),
 290                        IS_AVAIL1(cpu->extn.barrel, "barrel-shift "),
 291                        IS_AVAIL1(cpu->extn.swap, "swap "),
 292                        IS_AVAIL1(cpu->extn.minmax, "minmax "),
 293                        IS_AVAIL1(cpu->extn.crc, "crc "),
 294                        IS_AVAIL2(cpu->extn.swape, "swape", CONFIG_ARC_HAS_SWAPE));
 295
 296         if (cpu->bpu.ver)
 297                 n += scnprintf(buf + n, len - n,
 298                               "BPU\t\t: %s%s match, cache:%d, Predict Table:%d",
 299                               IS_AVAIL1(cpu->bpu.full, "full"),
 300                               IS_AVAIL1(!cpu->bpu.full, "partial"),
 301                               cpu->bpu.num_cache, cpu->bpu.num_pred);
 302
 303         if (is_isa_arcv2()) {
 304                 struct bcr_lpb lpb;
 305
 306                 READ_BCR(ARC_REG_LPB_BUILD, lpb);
 307                 if (lpb.ver) {
 308                         unsigned int ctl;
 309                         ctl = read_aux_reg(ARC_REG_LPB_CTRL);
 310
 311                         n += scnprintf(buf + n, len - n, " Loop Buffer:%d %s",
 312                                 lpb.entries,
 313                                 IS_DISABLED_RUN(!ctl));
 314                 }
 315         }
 316
 317         n += scnprintf(buf + n, len - n, "\n");
 318         return buf;
 319 }
 320
 321 static char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
 322 {
 323         int n = 0;
 324         struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
 325
 326         FIX_PTR(cpu);
 327
 328         n += scnprintf(buf + n, len - n, "Vector Table\t: %#x\n", cpu->vec_base);
 329
 330         if (cpu->extn.fpu_sp || cpu->extn.fpu_dp)
 331                 n += scnprintf(buf + n, len - n, "FPU\t\t: %s%s\n",
 332                                IS_AVAIL1(cpu->extn.fpu_sp, "SP "),
 333                                IS_AVAIL1(cpu->extn.fpu_dp, "DP "));
 334
 335         if (cpu->extn.debug)
 336                 n += scnprintf(buf + n, len - n, "DEBUG\t\t: %s%s%s\n",
 337                                IS_AVAIL1(cpu->extn.ap, "ActionPoint "),
 338                                IS_AVAIL1(cpu->extn.smart, "smaRT "),
 339                                IS_AVAIL1(cpu->extn.rtt, "RTT "));
 340
 341         if (cpu->dccm.sz || cpu->iccm.sz)
 342                 n += scnprintf(buf + n, len - n, "Extn [CCM]\t: DCCM @ %x, %d KB / ICCM: @ %x, %d KB\n",
 343                                cpu->dccm.base_addr, TO_KB(cpu->dccm.sz),
 344                                cpu->iccm.base_addr, TO_KB(cpu->iccm.sz));
 345
 346         if (is_isa_arcv2()) {
 347
 348                 /* Error Protection: ECC/Parity */
 349                 struct bcr_erp erp;
 350                 READ_BCR(ARC_REG_ERP_BUILD, erp);
 351
 352                 if (erp.ver) {
 353                         struct  ctl_erp ctl;
 354                         READ_BCR(ARC_REG_ERP_CTRL, ctl);
 355
 356                         /* inverted bits: 0 means enabled */
 357                         n += scnprintf(buf + n, len - n, "Extn [ECC]\t: %s%s%s%s%s%s\n",
 358                                 IS_AVAIL3(erp.ic,  !ctl.dpi, "IC "),
 359                                 IS_AVAIL3(erp.dc,  !ctl.dpd, "DC "),
 360                                 IS_AVAIL3(erp.mmu, !ctl.mpd, "MMU "));
 361                 }
 362         }
 363
 364         n += scnprintf(buf + n, len - n, "OS ABI [v%d]\t: %s\n",
 365                         EF_ARC_OSABI_CURRENT >> 8,
 366                         EF_ARC_OSABI_CURRENT == EF_ARC_OSABI_V3 ?
 367                         "no-legacy-syscalls" : "64-bit data any register aligned");
 368
 369         return buf;
 370 }
 371
 372 static void arc_chk_core_config(void)
 373 {
 374         struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
 375         int saved = 0, present = 0;
 376         char *opt_nm = NULL;;
 377
 378         if (!cpu->extn.timer0)
 379                 panic("Timer0 is not present!\n");
 380
 381         if (!cpu->extn.timer1)
 382                 panic("Timer1 is not present!\n");
 383
 384 #ifdef CONFIG_ARC_HAS_DCCM
 385         /*
 386          * DCCM can be arbit placed in hardware.
 387          * Make sure it's placement/sz matches what Linux is built with
 388          */
 389         if ((unsigned int)__arc_dccm_base != cpu->dccm.base_addr)
 390                 panic("Linux built with incorrect DCCM Base address\n");
 391
 392         if (CONFIG_ARC_DCCM_SZ != cpu->dccm.sz)
 393                 panic("Linux built with incorrect DCCM Size\n");
 394 #endif
 395
 396 #ifdef CONFIG_ARC_HAS_ICCM
 397         if (CONFIG_ARC_ICCM_SZ != cpu->iccm.sz)
 398                 panic("Linux built with incorrect ICCM Size\n");
 399 #endif
 400
 401         /*
 402          * FP hardware/software config sanity
 403          * -If hardware present, kernel needs to save/restore FPU state
 404          * -If not, it will crash trying to save/restore the non-existant regs
 405          */
 406
 407         if (is_isa_arcompact()) {
 408                 opt_nm = "CONFIG_ARC_FPU_SAVE_RESTORE";
 409                 saved = IS_ENABLED(CONFIG_ARC_FPU_SAVE_RESTORE);
 410
 411                 /* only DPDP checked since SP has no arch visible regs */
 412                 present = cpu->extn.fpu_dp;
 413         } else {
 414                 opt_nm = "CONFIG_ARC_HAS_ACCL_REGS";
 415                 saved = IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS);
 416
 417                 /* Accumulator Low:High pair (r58:59) present if DSP MPY or FPU */
 418                 present = cpu->extn_mpy.dsp | cpu->extn.fpu_sp | cpu->extn.fpu_dp;
 419         }
 420
 421         if (present && !saved)
 422                 pr_warn("Enable %s for working apps\n", opt_nm);
 423         else if (!present && saved)
 424                 panic("Disable %s, hardware NOT present\n", opt_nm);
 425 }
 426
 427 /*
 428  * Initialize and setup the processor core
 429  * This is called by all the CPUs thus should not do special case stuff
 430  *    such as only for boot CPU etc
 431  */
 432
 433 void setup_processor(void)
 434 {
 435         char str[512];
 436         int cpu_id = smp_processor_id();
 437
 438         read_arc_build_cfg_regs();
 439         arc_init_IRQ();
 440
 441         pr_info("%s", arc_cpu_mumbojumbo(cpu_id, str, sizeof(str)));
 442
 443         arc_mmu_init();
 444         arc_cache_init();
 445
 446         pr_info("%s", arc_extn_mumbojumbo(cpu_id, str, sizeof(str)));
 447         pr_info("%s", arc_platform_smp_cpuinfo());
 448
 449         arc_chk_core_config();
 450 }
 451
 452 static inline int is_kernel(unsigned long addr)
 453 {
 454         if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
 455                 return 1;
 456         return 0;
 457 }
 458
 459 void __init setup_arch(char **cmdline_p)
 460 {
 461 #ifdef CONFIG_ARC_UBOOT_SUPPORT
 462         /* make sure that uboot passed pointer to cmdline/dtb is valid */
 463         if (uboot_tag && is_kernel((unsigned long)uboot_arg))
 464                 panic("Invalid uboot arg\n");
 465
 466         /* See if u-boot passed an external Device Tree blob */
 467         machine_desc = setup_machine_fdt(uboot_arg);    /* uboot_tag == 2 */
 468         if (!machine_desc)
 469 #endif
 470         {
 471                 /* No, so try the embedded one */
 472                 machine_desc = setup_machine_fdt(__dtb_start);
 473                 if (!machine_desc)
 474                         panic("Embedded DT invalid\n");
 475
 476                 /*
 477                  * If we are here, it is established that @uboot_arg didn't
 478                  * point to DT blob. Instead if u-boot says it is cmdline,
 479                  * append to embedded DT cmdline.
 480                  * setup_machine_fdt() would have populated @boot_command_line
 481                  */
 482                 if (uboot_tag == 1) {
 483                         /* Ensure a whitespace between the 2 cmdlines */
 484                         strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
 485                         strlcat(boot_command_line, uboot_arg,
 486                                 COMMAND_LINE_SIZE);
 487                 }
 488         }
 489
 490         /* Save unparsed command line copy for /proc/cmdline */
 491         *cmdline_p = boot_command_line;
 492
 493         /* To force early parsing of things like mem=xxx */
 494         parse_early_param();
 495
 496         /* Platform/board specific: e.g. early console registration */
 497         if (machine_desc->init_early)
 498                 machine_desc->init_early();
 499
 500         smp_init_cpus();
 501
 502         setup_processor();
 503         setup_arch_memory();
 504
 505         /* copy flat DT out of .init and then unflatten it */
 506         unflatten_and_copy_device_tree();
 507
 508         /* Can be issue if someone passes cmd line arg "ro"
 509          * But that is unlikely so keeping it as it is
 510          */
 511         root_mountflags &= ~MS_RDONLY;
 512
 513 #if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
 514         conswitchp = &dummy_con;
 515 #endif
 516
 517         arc_unwind_init();
 518 }
 519
 520 /*
 521  * Called from start_kernel() - boot CPU only
 522  */
 523 void __init time_init(void)
 524 {
 525         of_clk_init(NULL);
 526         timer_probe();
 527 }
 528
 529 static int __init customize_machine(void)
 530 {
 531         if (machine_desc->init_machine)
 532                 machine_desc->init_machine();
 533
 534         return 0;
 535 }
 536 arch_initcall(customize_machine);
 537
 538 static int __init init_late_machine(void)
 539 {
 540         if (machine_desc->init_late)
 541                 machine_desc->init_late();
 542
 543         return 0;
 544 }
 545 late_initcall(init_late_machine);
 546 /*
 547  *  Get CPU information for use by the procfs.
 548  */
 549
 550 #define cpu_to_ptr(c)   ((void *)(0xFFFF0000 | (unsigned int)(c)))
 551 #define ptr_to_cpu(p)   (~0xFFFF0000UL & (unsigned int)(p))
 552
 553 static int show_cpuinfo(struct seq_file *m, void *v)
 554 {
 555         char *str;
 556         int cpu_id = ptr_to_cpu(v);
 557         struct device *cpu_dev = get_cpu_device(cpu_id);
 558         struct clk *cpu_clk;
 559         unsigned long freq = 0;
 560
 561         if (!cpu_online(cpu_id)) {
 562                 seq_printf(m, "processor [%d]\t: Offline\n", cpu_id);
 563                 goto done;
 564         }
 565
 566         str = (char *)__get_free_page(GFP_KERNEL);
 567         if (!str)
 568                 goto done;
 569
 570         seq_printf(m, arc_cpu_mumbojumbo(cpu_id, str, PAGE_SIZE));
 571
 572         cpu_clk = clk_get(cpu_dev, NULL);
 573         if (IS_ERR(cpu_clk)) {
 574                 seq_printf(m, "CPU speed \t: Cannot get clock for processor [%d]\n",
 575                            cpu_id);
 576         } else {
 577                 freq = clk_get_rate(cpu_clk);
 578         }
 579         if (freq)
 580                 seq_printf(m, "CPU speed\t: %lu.%02lu Mhz\n",
 581                            freq / 1000000, (freq / 10000) % 100);
 582
 583         seq_printf(m, "Bogo MIPS\t: %lu.%02lu\n",
 584                    loops_per_jiffy / (500000 / HZ),
 585                    (loops_per_jiffy / (5000 / HZ)) % 100);
 586
 587         seq_printf(m, arc_mmu_mumbojumbo(cpu_id, str, PAGE_SIZE));
 588         seq_printf(m, arc_cache_mumbojumbo(cpu_id, str, PAGE_SIZE));
 589         seq_printf(m, arc_extn_mumbojumbo(cpu_id, str, PAGE_SIZE));
 590         seq_printf(m, arc_platform_smp_cpuinfo());
 591
 592         free_page((unsigned long)str);
 593 done:
 594         seq_printf(m, "\n");
 595
 596         return 0;
 597 }
 598
 599 static void *c_start(struct seq_file *m, loff_t *pos)
 600 {
 601         /*
 602          * Callback returns cpu-id to iterator for show routine, NULL to stop.
 603          * However since NULL is also a valid cpu-id (0), we use a round-about
 604          * way to pass it w/o having to kmalloc/free a 2 byte string.
 605          * Encode cpu-id as 0xFFcccc, which is decoded by show routine.
 606          */
 607         return *pos < nr_cpu_ids ? cpu_to_ptr(*pos) : NULL;
 608 }
 609
 610 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 611 {
 612         ++*pos;
 613         return c_start(m, pos);
 614 }
 615
 616 static void c_stop(struct seq_file *m, void *v)
 617 {
 618 }
 619
 620 const struct seq_operations cpuinfo_op = {
 621         .start  = c_start,
 622         .next   = c_next,
 623         .stop   = c_stop,
 624         .show   = show_cpuinfo
 625 };
 626
 627 static DEFINE_PER_CPU(struct cpu, cpu_topology);
 628
 629 static int __init topology_init(void)
 630 {
 631         int cpu;
 632
 633         for_each_present_cpu(cpu)
 634             register_cpu(&per_cpu(cpu_topology, cpu), cpu);
 635
 636         return 0;
 637 }
 638
 639 subsys_initcall(topology_init);