arch/powerpc/platforms/powermac/setup.c

   1 /*
   2  *  Powermac setup and early boot code plus other random bits.
   3  *
   4  *  PowerPC version
   5  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   6  *
   7  *  Adapted for Power Macintosh by Paul Mackerras
   8  *    Copyright (C) 1996 Paul Mackerras (paulus@samba.org)
   9  *
  10  *  Derived from "arch/alpha/kernel/setup.c"
  11  *    Copyright (C) 1995 Linus Torvalds
  12  *
  13  *  Maintained by Benjamin Herrenschmidt (benh@kernel.crashing.org)
  14  *
  15  *  This program is free software; you can redistribute it and/or
  16  *  modify it under the terms of the GNU General Public License
  17  *  as published by the Free Software Foundation; either version
  18  *  2 of the License, or (at your option) any later version.
  19  *
  20  */
  21
  22 /*
  23  * bootup setup stuff..
  24  */
  25
  26 #include <linux/init.h>
  27 #include <linux/errno.h>
  28 #include <linux/sched.h>
  29 #include <linux/kernel.h>
  30 #include <linux/mm.h>
  31 #include <linux/stddef.h>
  32 #include <linux/unistd.h>
  33 #include <linux/ptrace.h>
  34 #include <linux/slab.h>
  35 #include <linux/user.h>
  36 #include <linux/tty.h>
  37 #include <linux/string.h>
  38 #include <linux/delay.h>
  39 #include <linux/ioport.h>
  40 #include <linux/major.h>
  41 #include <linux/initrd.h>
  42 #include <linux/vt_kern.h>
  43 #include <linux/console.h>
  44 #include <linux/pci.h>
  45 #include <linux/adb.h>
  46 #include <linux/cuda.h>
  47 #include <linux/pmu.h>
  48 #include <linux/irq.h>
  49 #include <linux/seq_file.h>
  50 #include <linux/root_dev.h>
  51 #include <linux/bitops.h>
  52 #include <linux/suspend.h>
  53 #include <linux/of_device.h>
  54 #include <linux/of_platform.h>
  55 #include <linux/lmb.h>
  56
  57 #include <asm/reg.h>
  58 #include <asm/sections.h>
  59 #include <asm/prom.h>
  60 #include <asm/system.h>
  61 #include <asm/pgtable.h>
  62 #include <asm/io.h>
  63 #include <asm/kexec.h>
  64 #include <asm/pci-bridge.h>
  65 #include <asm/ohare.h>
  66 #include <asm/mediabay.h>
  67 #include <asm/machdep.h>
  68 #include <asm/dma.h>
  69 #include <asm/cputable.h>
  70 #include <asm/btext.h>
  71 #include <asm/pmac_feature.h>
  72 #include <asm/time.h>
  73 #include <asm/mmu_context.h>
  74 #include <asm/iommu.h>
  75 #include <asm/smu.h>
  76 #include <asm/pmc.h>
  77 #include <asm/udbg.h>
  78
  79 #include "pmac.h"
  80
  81 #undef SHOW_GATWICK_IRQS
  82
  83 int ppc_override_l2cr = 0;
  84 int ppc_override_l2cr_value;
  85 int has_l2cache = 0;
  86
  87 int pmac_newworld;
  88
  89 static int current_root_goodness = -1;
  90
  91 extern struct machdep_calls pmac_md;
  92
  93 #define DEFAULT_ROOT_DEVICE Root_SDA1   /* sda1 - slightly silly choice */
  94
  95 #ifdef CONFIG_PPC64
  96 int sccdbg;
  97 #endif
  98
  99 sys_ctrler_t sys_ctrler = SYS_CTRLER_UNKNOWN;
 100 EXPORT_SYMBOL(sys_ctrler);
 101
 102 #ifdef CONFIG_PMAC_SMU
 103 unsigned long smu_cmdbuf_abs;
 104 EXPORT_SYMBOL(smu_cmdbuf_abs);
 105 #endif
 106
 107 #ifdef CONFIG_SMP
 108 extern struct smp_ops_t psurge_smp_ops;
 109 extern struct smp_ops_t core99_smp_ops;
 110 #endif /* CONFIG_SMP */
 111
 112 static void pmac_show_cpuinfo(struct seq_file *m)
 113 {
 114         struct device_node *np;
 115         const char *pp;
 116         int plen;
 117         int mbmodel;
 118         unsigned int mbflags;
 119         char* mbname;
 120
 121         mbmodel = pmac_call_feature(PMAC_FTR_GET_MB_INFO, NULL,
 122                                     PMAC_MB_INFO_MODEL, 0);
 123         mbflags = pmac_call_feature(PMAC_FTR_GET_MB_INFO, NULL,
 124                                     PMAC_MB_INFO_FLAGS, 0);
 125         if (pmac_call_feature(PMAC_FTR_GET_MB_INFO, NULL, PMAC_MB_INFO_NAME,
 126                               (long) &mbname) != 0)
 127                 mbname = "Unknown";
 128
 129         /* find motherboard type */
 130         seq_printf(m, "machine\t\t: ");
 131         np = of_find_node_by_path("/");
 132         if (np != NULL) {
 133                 pp = of_get_property(np, "model", NULL);
 134                 if (pp != NULL)
 135                         seq_printf(m, "%s\n", pp);
 136                 else
 137                         seq_printf(m, "PowerMac\n");
 138                 pp = of_get_property(np, "compatible", &plen);
 139                 if (pp != NULL) {
 140                         seq_printf(m, "motherboard\t:");
 141                         while (plen > 0) {
 142                                 int l = strlen(pp) + 1;
 143                                 seq_printf(m, " %s", pp);
 144                                 plen -= l;
 145                                 pp += l;
 146                         }
 147                         seq_printf(m, "\n");
 148                 }
 149                 of_node_put(np);
 150         } else
 151                 seq_printf(m, "PowerMac\n");
 152
 153         /* print parsed model */
 154         seq_printf(m, "detected as\t: %d (%s)\n", mbmodel, mbname);
 155         seq_printf(m, "pmac flags\t: %08x\n", mbflags);
 156
 157         /* find l2 cache info */
 158         np = of_find_node_by_name(NULL, "l2-cache");
 159         if (np == NULL)
 160                 np = of_find_node_by_type(NULL, "cache");
 161         if (np != NULL) {
 162                 const unsigned int *ic =
 163                         of_get_property(np, "i-cache-size", NULL);
 164                 const unsigned int *dc =
 165                         of_get_property(np, "d-cache-size", NULL);
 166                 seq_printf(m, "L2 cache\t:");
 167                 has_l2cache = 1;
 168                 if (of_get_property(np, "cache-unified", NULL) != 0 && dc) {
 169                         seq_printf(m, " %dK unified", *dc / 1024);
 170                 } else {
 171                         if (ic)
 172                                 seq_printf(m, " %dK instruction", *ic / 1024);
 173                         if (dc)
 174                                 seq_printf(m, "%s %dK data",
 175                                            (ic? " +": ""), *dc / 1024);
 176                 }
 177                 pp = of_get_property(np, "ram-type", NULL);
 178                 if (pp)
 179                         seq_printf(m, " %s", pp);
 180                 seq_printf(m, "\n");
 181                 of_node_put(np);
 182         }
 183
 184         /* Indicate newworld/oldworld */
 185         seq_printf(m, "pmac-generation\t: %s\n",
 186                    pmac_newworld ? "NewWorld" : "OldWorld");
 187 }
 188
 189 #ifndef CONFIG_ADB_CUDA
 190 int find_via_cuda(void)
 191 {
 192         struct device_node *dn = of_find_node_by_name(NULL, "via-cuda");
 193
 194         if (!dn)
 195                 return 0;
 196         of_node_put(dn);
 197         printk("WARNING ! Your machine is CUDA-based but your kernel\n");
 198         printk("          wasn't compiled with CONFIG_ADB_CUDA option !\n");
 199         return 0;
 200 }
 201 #endif
 202
 203 #ifndef CONFIG_ADB_PMU
 204 int find_via_pmu(void)
 205 {
 206         struct device_node *dn = of_find_node_by_name(NULL, "via-pmu");
 207
 208         if (!dn)
 209                 return 0;
 210         of_node_put(dn);
 211         printk("WARNING ! Your machine is PMU-based but your kernel\n");
 212         printk("          wasn't compiled with CONFIG_ADB_PMU option !\n");
 213         return 0;
 214 }
 215 #endif
 216
 217 #ifndef CONFIG_PMAC_SMU
 218 int smu_init(void)
 219 {
 220         /* should check and warn if SMU is present */
 221         return 0;
 222 }
 223 #endif
 224
 225 #ifdef CONFIG_PPC32
 226 static volatile u32 *sysctrl_regs;
 227
 228 static void __init ohare_init(void)
 229 {
 230         struct device_node *dn;
 231
 232         /* this area has the CPU identification register
 233            and some registers used by smp boards */
 234         sysctrl_regs = (volatile u32 *) ioremap(0xf8000000, 0x1000);
 235
 236         /*
 237          * Turn on the L2 cache.
 238          * We assume that we have a PSX memory controller iff
 239          * we have an ohare I/O controller.
 240          */
 241         dn = of_find_node_by_name(NULL, "ohare");
 242         if (dn) {
 243                 of_node_put(dn);
 244                 if (((sysctrl_regs[2] >> 24) & 0xf) >= 3) {
 245                         if (sysctrl_regs[4] & 0x10)
 246                                 sysctrl_regs[4] |= 0x04000020;
 247                         else
 248                                 sysctrl_regs[4] |= 0x04000000;
 249                         if(has_l2cache)
 250                                 printk(KERN_INFO "Level 2 cache enabled\n");
 251                 }
 252         }
 253 }
 254
 255 static void __init l2cr_init(void)
 256 {
 257         /* Checks "l2cr-value" property in the registry */
 258         if (cpu_has_feature(CPU_FTR_L2CR)) {
 259                 struct device_node *np = of_find_node_by_name(NULL, "cpus");
 260                 if (np == 0)
 261                         np = of_find_node_by_type(NULL, "cpu");
 262                 if (np != 0) {
 263                         const unsigned int *l2cr =
 264                                 of_get_property(np, "l2cr-value", NULL);
 265                         if (l2cr != 0) {
 266                                 ppc_override_l2cr = 1;
 267                                 ppc_override_l2cr_value = *l2cr;
 268                                 _set_L2CR(0);
 269                                 _set_L2CR(ppc_override_l2cr_value);
 270                         }
 271                         of_node_put(np);
 272                 }
 273         }
 274
 275         if (ppc_override_l2cr)
 276                 printk(KERN_INFO "L2CR overridden (0x%x), "
 277                        "backside cache is %s\n",
 278                        ppc_override_l2cr_value,
 279                        (ppc_override_l2cr_value & 0x80000000)
 280                                 ? "enabled" : "disabled");
 281 }
 282 #endif
 283
 284 static void __init pmac_setup_arch(void)
 285 {
 286         struct device_node *cpu, *ic;
 287         const int *fp;
 288         unsigned long pvr;
 289
 290         pvr = PVR_VER(mfspr(SPRN_PVR));
 291
 292         /* Set loops_per_jiffy to a half-way reasonable value,
 293            for use until calibrate_delay gets called. */
 294         loops_per_jiffy = 50000000 / HZ;
 295         cpu = of_find_node_by_type(NULL, "cpu");
 296         if (cpu != NULL) {
 297                 fp = of_get_property(cpu, "clock-frequency", NULL);
 298                 if (fp != NULL) {
 299                         if (pvr >= 0x30 && pvr < 0x80)
 300                                 /* PPC970 etc. */
 301                                 loops_per_jiffy = *fp / (3 * HZ);
 302                         else if (pvr == 4 || pvr >= 8)
 303                                 /* 604, G3, G4 etc. */
 304                                 loops_per_jiffy = *fp / HZ;
 305                         else
 306                                 /* 601, 603, etc. */
 307                                 loops_per_jiffy = *fp / (2 * HZ);
 308                 }
 309                 of_node_put(cpu);
 310         }
 311
 312         /* See if newworld or oldworld */
 313         for (ic = NULL; (ic = of_find_all_nodes(ic)) != NULL; )
 314                 if (of_get_property(ic, "interrupt-controller", NULL))
 315                         break;
 316         if (ic) {
 317                 pmac_newworld = 1;
 318                 of_node_put(ic);
 319         }
 320
 321         /* Lookup PCI hosts */
 322         pmac_pci_init();
 323
 324 #ifdef CONFIG_PPC32
 325         ohare_init();
 326         l2cr_init();
 327 #endif /* CONFIG_PPC32 */
 328
 329         find_via_cuda();
 330         find_via_pmu();
 331         smu_init();
 332
 333 #if defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE) || \
 334     defined(CONFIG_PPC64)
 335         pmac_nvram_init();
 336 #endif
 337
 338 #ifdef CONFIG_PPC32
 339 #ifdef CONFIG_BLK_DEV_INITRD
 340         if (initrd_start)
 341                 ROOT_DEV = Root_RAM0;
 342         else
 343 #endif
 344                 ROOT_DEV = DEFAULT_ROOT_DEVICE;
 345 #endif
 346
 347 #ifdef CONFIG_SMP
 348         /* Check for Core99 */
 349         ic = of_find_node_by_name(NULL, "uni-n");
 350         if (!ic)
 351                 ic = of_find_node_by_name(NULL, "u3");
 352         if (!ic)
 353                 ic = of_find_node_by_name(NULL, "u4");
 354         if (ic) {
 355                 of_node_put(ic);
 356                 smp_ops = &core99_smp_ops;
 357         }
 358 #ifdef CONFIG_PPC32
 359         else {
 360                 /*
 361                  * We have to set bits in cpu_possible_map here since the
 362                  * secondary CPU(s) aren't in the device tree, and
 363                  * setup_per_cpu_areas only allocates per-cpu data for
 364                  * CPUs in the cpu_possible_map.
 365                  */
 366                 int cpu;
 367
 368                 for (cpu = 1; cpu < 4 && cpu < NR_CPUS; ++cpu)
 369                         cpu_set(cpu, cpu_possible_map);
 370                 smp_ops = &psurge_smp_ops;
 371         }
 372 #endif
 373 #endif /* CONFIG_SMP */
 374
 375 #ifdef CONFIG_ADB
 376         if (strstr(cmd_line, "adb_sync")) {
 377                 extern int __adb_probe_sync;
 378                 __adb_probe_sync = 1;
 379         }
 380 #endif /* CONFIG_ADB */
 381 }
 382
 383 #ifdef CONFIG_SCSI
 384 void note_scsi_host(struct device_node *node, void *host)
 385 {
 386 }
 387 EXPORT_SYMBOL(note_scsi_host);
 388 #endif
 389
 390 static int initializing = 1;
 391
 392 static int pmac_late_init(void)
 393 {
 394         initializing = 0;
 395         /* this is udbg (which is __init) and we can later use it during
 396          * cpu hotplug (in smp_core99_kick_cpu) */
 397         ppc_md.progress = NULL;
 398         return 0;
 399 }
 400 machine_late_initcall(powermac, pmac_late_init);
 401
 402 /*
 403  * This is __init_refok because we check for "initializing" before
 404  * touching any of the __init sensitive things and "initializing"
 405  * will be false after __init time. This can't be __init because it
 406  * can be called whenever a disk is first accessed.
 407  */
 408 void __init_refok note_bootable_part(dev_t dev, int part, int goodness)
 409 {
 410         char *p;
 411
 412         if (!initializing)
 413                 return;
 414         if ((goodness <= current_root_goodness) &&
 415             ROOT_DEV != DEFAULT_ROOT_DEVICE)
 416                 return;
 417         p = strstr(boot_command_line, "root=");
 418         if (p != NULL && (p == boot_command_line || p[-1] == ' '))
 419                 return;
 420
 421         ROOT_DEV = dev + part;
 422         current_root_goodness = goodness;
 423 }
 424
 425 #ifdef CONFIG_ADB_CUDA
 426 static void cuda_restart(void)
 427 {
 428         struct adb_request req;
 429
 430         cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_RESET_SYSTEM);
 431         for (;;)
 432                 cuda_poll();
 433 }
 434
 435 static void cuda_shutdown(void)
 436 {
 437         struct adb_request req;
 438
 439         cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_POWERDOWN);
 440         for (;;)
 441                 cuda_poll();
 442 }
 443
 444 #else
 445 #define cuda_restart()
 446 #define cuda_shutdown()
 447 #endif
 448
 449 #ifndef CONFIG_ADB_PMU
 450 #define pmu_restart()
 451 #define pmu_shutdown()
 452 #endif
 453
 454 #ifndef CONFIG_PMAC_SMU
 455 #define smu_restart()
 456 #define smu_shutdown()
 457 #endif
 458
 459 static void pmac_restart(char *cmd)
 460 {
 461         switch (sys_ctrler) {
 462         case SYS_CTRLER_CUDA:
 463                 cuda_restart();
 464                 break;
 465         case SYS_CTRLER_PMU:
 466                 pmu_restart();
 467                 break;
 468         case SYS_CTRLER_SMU:
 469                 smu_restart();
 470                 break;
 471         default: ;
 472         }
 473 }
 474
 475 static void pmac_power_off(void)
 476 {
 477         switch (sys_ctrler) {
 478         case SYS_CTRLER_CUDA:
 479                 cuda_shutdown();
 480                 break;
 481         case SYS_CTRLER_PMU:
 482                 pmu_shutdown();
 483                 break;
 484         case SYS_CTRLER_SMU:
 485                 smu_shutdown();
 486                 break;
 487         default: ;
 488         }
 489 }
 490
 491 static void
 492 pmac_halt(void)
 493 {
 494         pmac_power_off();
 495 }
 496
 497 /*
 498  * Early initialization.
 499  */
 500 static void __init pmac_init_early(void)
 501 {
 502         /* Enable early btext debug if requested */
 503         if (strstr(cmd_line, "btextdbg")) {
 504                 udbg_adb_init_early();
 505                 register_early_udbg_console();
 506         }
 507
 508         /* Probe motherboard chipset */
 509         pmac_feature_init();
 510
 511         /* Initialize debug stuff */
 512         udbg_scc_init(!!strstr(cmd_line, "sccdbg"));
 513         udbg_adb_init(!!strstr(cmd_line, "btextdbg"));
 514
 515 #ifdef CONFIG_PPC64
 516         iommu_init_early_dart();
 517 #endif
 518 }
 519
 520 static int __init pmac_declare_of_platform_devices(void)
 521 {
 522         struct device_node *np;
 523
 524         if (machine_is(chrp))
 525                 return -1;
 526
 527         np = of_find_node_by_name(NULL, "valkyrie");
 528         if (np)
 529                 of_platform_device_create(np, "valkyrie", NULL);
 530         np = of_find_node_by_name(NULL, "platinum");
 531         if (np)
 532                 of_platform_device_create(np, "platinum", NULL);
 533         np = of_find_node_by_type(NULL, "smu");
 534         if (np) {
 535                 of_platform_device_create(np, "smu", NULL);
 536                 of_node_put(np);
 537         }
 538
 539         return 0;
 540 }
 541 machine_device_initcall(powermac, pmac_declare_of_platform_devices);
 542
 543 #ifdef CONFIG_SERIAL_PMACZILOG_CONSOLE
 544 /*
 545  * This is called very early, as part of console_init() (typically just after
 546  * time_init()). This function is respondible for trying to find a good
 547  * default console on serial ports. It tries to match the open firmware
 548  * default output with one of the available serial console drivers.
 549  */
 550 static int __init check_pmac_serial_console(void)
 551 {
 552         struct device_node *prom_stdout = NULL;
 553         int offset = 0;
 554         const char *name;
 555 #ifdef CONFIG_SERIAL_PMACZILOG_TTYS
 556         char *devname = "ttyS";
 557 #else
 558         char *devname = "ttyPZ";
 559 #endif
 560
 561         pr_debug(" -> check_pmac_serial_console()\n");
 562
 563         /* The user has requested a console so this is already set up. */
 564         if (strstr(boot_command_line, "console=")) {
 565                 pr_debug(" console was specified !\n");
 566                 return -EBUSY;
 567         }
 568
 569         if (!of_chosen) {
 570                 pr_debug(" of_chosen is NULL !\n");
 571                 return -ENODEV;
 572         }
 573
 574         /* We are getting a weird phandle from OF ... */
 575         /* ... So use the full path instead */
 576         name = of_get_property(of_chosen, "linux,stdout-path", NULL);
 577         if (name == NULL) {
 578                 pr_debug(" no linux,stdout-path !\n");
 579                 return -ENODEV;
 580         }
 581         prom_stdout = of_find_node_by_path(name);
 582         if (!prom_stdout) {
 583                 pr_debug(" can't find stdout package %s !\n", name);
 584                 return -ENODEV;
 585         }
 586         pr_debug("stdout is %s\n", prom_stdout->full_name);
 587
 588         name = of_get_property(prom_stdout, "name", NULL);
 589         if (!name) {
 590                 pr_debug(" stdout package has no name !\n");
 591                 goto not_found;
 592         }
 593
 594         if (strcmp(name, "ch-a") == 0)
 595                 offset = 0;
 596         else if (strcmp(name, "ch-b") == 0)
 597                 offset = 1;
 598         else
 599                 goto not_found;
 600         of_node_put(prom_stdout);
 601
 602         pr_debug("Found serial console at %s%d\n", devname, offset);
 603
 604         return add_preferred_console(devname, offset, NULL);
 605
 606  not_found:
 607         pr_debug("No preferred console found !\n");
 608         of_node_put(prom_stdout);
 609         return -ENODEV;
 610 }
 611 console_initcall(check_pmac_serial_console);
 612
 613 #endif /* CONFIG_SERIAL_PMACZILOG_CONSOLE */
 614
 615 /*
 616  * Called very early, MMU is off, device-tree isn't unflattened
 617  */
 618 static int __init pmac_probe(void)
 619 {
 620         unsigned long root = of_get_flat_dt_root();
 621
 622         if (!of_flat_dt_is_compatible(root, "Power Macintosh") &&
 623             !of_flat_dt_is_compatible(root, "MacRISC"))
 624                 return 0;
 625
 626 #ifdef CONFIG_PPC64
 627         /*
 628          * On U3, the DART (iommu) must be allocated now since it
 629          * has an impact on htab_initialize (due to the large page it
 630          * occupies having to be broken up so the DART itself is not
 631          * part of the cacheable linar mapping
 632          */
 633         alloc_dart_table();
 634
 635         hpte_init_native();
 636 #endif
 637
 638 #ifdef CONFIG_PPC32
 639         /* isa_io_base gets set in pmac_pci_init */
 640         ISA_DMA_THRESHOLD = ~0L;
 641         DMA_MODE_READ = 1;
 642         DMA_MODE_WRITE = 2;
 643 #endif /* CONFIG_PPC32 */
 644
 645 #ifdef CONFIG_PMAC_SMU
 646         /*
 647          * SMU based G5s need some memory below 2Gb, at least the current
 648          * driver needs that. We have to allocate it now. We allocate 4k
 649          * (1 small page) for now.
 650          */
 651         smu_cmdbuf_abs = lmb_alloc_base(4096, 4096, 0x80000000UL);
 652 #endif /* CONFIG_PMAC_SMU */
 653
 654         return 1;
 655 }
 656
 657 #ifdef CONFIG_PPC64
 658 /* Move that to pci.c */
 659 static int pmac_pci_probe_mode(struct pci_bus *bus)
 660 {
 661         struct device_node *node = bus->sysdata;
 662
 663         /* We need to use normal PCI probing for the AGP bus,
 664          * since the device for the AGP bridge isn't in the tree.
 665          * Same for the PCIe host on U4 and the HT host bridge.
 666          */
 667         if (bus->self == NULL && (of_device_is_compatible(node, "u3-agp") ||
 668                                   of_device_is_compatible(node, "u4-pcie") ||
 669                                   of_device_is_compatible(node, "u3-ht")))
 670                 return PCI_PROBE_NORMAL;
 671         return PCI_PROBE_DEVTREE;
 672 }
 673
 674 #ifdef CONFIG_HOTPLUG_CPU
 675 /* access per cpu vars from generic smp.c */
 676 DECLARE_PER_CPU(int, cpu_state);
 677
 678 static void pmac_cpu_die(void)
 679 {
 680         /*
 681          * turn off as much as possible, we'll be
 682          * kicked out as this will only be invoked
 683          * on core99 platforms for now ...
 684          */
 685
 686         printk(KERN_INFO "CPU#%d offline\n", smp_processor_id());
 687         __get_cpu_var(cpu_state) = CPU_DEAD;
 688         smp_wmb();
 689
 690         /*
 691          * during the path that leads here preemption is disabled,
 692          * reenable it now so that when coming up preempt count is
 693          * zero correctly
 694          */
 695         preempt_enable();
 696
 697         /*
 698          * hard-disable interrupts for the non-NAP case, the NAP code
 699          * needs to re-enable interrupts (but soft-disables them)
 700          */
 701         hard_irq_disable();
 702
 703         while (1) {
 704                 /* let's not take timer interrupts too often ... */
 705                 set_dec(0x7fffffff);
 706
 707                 /* should always be true at this point */
 708                 if (cpu_has_feature(CPU_FTR_CAN_NAP))
 709                         power4_cpu_offline_powersave();
 710                 else {
 711                         HMT_low();
 712                         HMT_very_low();
 713                 }
 714         }
 715 }
 716 #endif /* CONFIG_HOTPLUG_CPU */
 717
 718 #endif /* CONFIG_PPC64 */
 719
 720 define_machine(powermac) {
 721         .name                   = "PowerMac",
 722         .probe                  = pmac_probe,
 723         .setup_arch             = pmac_setup_arch,
 724         .init_early             = pmac_init_early,
 725         .show_cpuinfo           = pmac_show_cpuinfo,
 726         .init_IRQ               = pmac_pic_init,
 727         .get_irq                = NULL, /* changed later */
 728         .pci_irq_fixup          = pmac_pci_irq_fixup,
 729         .restart                = pmac_restart,
 730         .power_off              = pmac_power_off,
 731         .halt                   = pmac_halt,
 732         .time_init              = pmac_time_init,
 733         .get_boot_time          = pmac_get_boot_time,
 734         .set_rtc_time           = pmac_set_rtc_time,
 735         .get_rtc_time           = pmac_get_rtc_time,
 736         .calibrate_decr         = pmac_calibrate_decr,
 737         .feature_call           = pmac_do_feature_call,
 738         .progress               = udbg_progress,
 739 #ifdef CONFIG_PPC64
 740         .pci_probe_mode         = pmac_pci_probe_mode,
 741         .power_save             = power4_idle,
 742         .enable_pmcs            = power4_enable_pmcs,
 743 #ifdef CONFIG_KEXEC
 744         .machine_kexec          = default_machine_kexec,
 745         .machine_kexec_prepare  = default_machine_kexec_prepare,
 746         .machine_crash_shutdown = default_machine_crash_shutdown,
 747 #endif
 748 #endif /* CONFIG_PPC64 */
 749 #ifdef CONFIG_PPC32
 750         .pcibios_enable_device_hook = pmac_pci_enable_device_hook,
 751         .pcibios_after_init     = pmac_pcibios_after_init,
 752         .phys_mem_access_prot   = pci_phys_mem_access_prot,
 753 #endif
 754 #if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PPC64)
 755         .cpu_die                = pmac_cpu_die,
 756 #endif
 757 };