arch/powerpc/kernel/setup-common.c

   1 /*
   2  * Common boot and setup code for both 32-bit and 64-bit.
   3  * Extracted from arch/powerpc/kernel/setup_64.c.
   4  *
   5  * Copyright (C) 2001 PPC64 Team, IBM Corp
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License
   9  *      as published by the Free Software Foundation; either version
  10  *      2 of the License, or (at your option) any later version.
  11  */
  12
  13 #undef DEBUG
  14
  15 #include <linux/module.h>
  16 #include <linux/string.h>
  17 #include <linux/sched.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/reboot.h>
  21 #include <linux/delay.h>
  22 #include <linux/initrd.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/seq_file.h>
  25 #include <linux/ioport.h>
  26 #include <linux/console.h>
  27 #include <linux/screen_info.h>
  28 #include <linux/root_dev.h>
  29 #include <linux/notifier.h>
  30 #include <linux/cpu.h>
  31 #include <linux/unistd.h>
  32 #include <linux/serial.h>
  33 #include <linux/serial_8250.h>
  34 #include <linux/debugfs.h>
  35 #include <linux/percpu.h>
  36 #include <linux/lmb.h>
  37 #include <linux/of_platform.h>
  38 #include <asm/io.h>
  39 #include <asm/paca.h>
  40 #include <asm/prom.h>
  41 #include <asm/processor.h>
  42 #include <asm/vdso_datapage.h>
  43 #include <asm/pgtable.h>
  44 #include <asm/smp.h>
  45 #include <asm/elf.h>
  46 #include <asm/machdep.h>
  47 #include <asm/time.h>
  48 #include <asm/cputable.h>
  49 #include <asm/sections.h>
  50 #include <asm/firmware.h>
  51 #include <asm/btext.h>
  52 #include <asm/nvram.h>
  53 #include <asm/setup.h>
  54 #include <asm/system.h>
  55 #include <asm/rtas.h>
  56 #include <asm/iommu.h>
  57 #include <asm/serial.h>
  58 #include <asm/cache.h>
  59 #include <asm/page.h>
  60 #include <asm/mmu.h>
  61 #include <asm/xmon.h>
  62 #include <asm/cputhreads.h>
  63 #include <mm/mmu_decl.h>
  64
  65 #include "setup.h"
  66
  67 #ifdef DEBUG
  68 #include <asm/udbg.h>
  69 #define DBG(fmt...) udbg_printf(fmt)
  70 #else
  71 #define DBG(fmt...)
  72 #endif
  73
  74 /* The main machine-dep calls structure
  75  */
  76 struct machdep_calls ppc_md;
  77 EXPORT_SYMBOL(ppc_md);
  78 struct machdep_calls *machine_id;
  79 EXPORT_SYMBOL(machine_id);
  80
  81 unsigned long klimit = (unsigned long) _end;
  82
  83 char cmd_line[COMMAND_LINE_SIZE];
  84
  85 /*
  86  * This still seems to be needed... -- paulus
  87  */
  88 struct screen_info screen_info = {
  89         .orig_x = 0,
  90         .orig_y = 25,
  91         .orig_video_cols = 80,
  92         .orig_video_lines = 25,
  93         .orig_video_isVGA = 1,
  94         .orig_video_points = 16
  95 };
  96
  97 #ifdef __DO_IRQ_CANON
  98 /* XXX should go elsewhere eventually */
  99 int ppc_do_canonicalize_irqs;
 100 EXPORT_SYMBOL(ppc_do_canonicalize_irqs);
 101 #endif
 102
 103 /* also used by kexec */
 104 void machine_shutdown(void)
 105 {
 106         if (ppc_md.machine_shutdown)
 107                 ppc_md.machine_shutdown();
 108 }
 109
 110 void machine_restart(char *cmd)
 111 {
 112         machine_shutdown();
 113         if (ppc_md.restart)
 114                 ppc_md.restart(cmd);
 115 #ifdef CONFIG_SMP
 116         smp_send_stop();
 117 #endif
 118         printk(KERN_EMERG "System Halted, OK to turn off power\n");
 119         local_irq_disable();
 120         while (1) ;
 121 }
 122
 123 void machine_power_off(void)
 124 {
 125         machine_shutdown();
 126         if (ppc_md.power_off)
 127                 ppc_md.power_off();
 128 #ifdef CONFIG_SMP
 129         smp_send_stop();
 130 #endif
 131         printk(KERN_EMERG "System Halted, OK to turn off power\n");
 132         local_irq_disable();
 133         while (1) ;
 134 }
 135 /* Used by the G5 thermal driver */
 136 EXPORT_SYMBOL_GPL(machine_power_off);
 137
 138 void (*pm_power_off)(void) = machine_power_off;
 139 EXPORT_SYMBOL_GPL(pm_power_off);
 140
 141 void machine_halt(void)
 142 {
 143         machine_shutdown();
 144         if (ppc_md.halt)
 145                 ppc_md.halt();
 146 #ifdef CONFIG_SMP
 147         smp_send_stop();
 148 #endif
 149         printk(KERN_EMERG "System Halted, OK to turn off power\n");
 150         local_irq_disable();
 151         while (1) ;
 152 }
 153
 154
 155 #ifdef CONFIG_TAU
 156 extern u32 cpu_temp(unsigned long cpu);
 157 extern u32 cpu_temp_both(unsigned long cpu);
 158 #endif /* CONFIG_TAU */
 159
 160 #ifdef CONFIG_SMP
 161 DEFINE_PER_CPU(unsigned int, cpu_pvr);
 162 #endif
 163
 164 static int show_cpuinfo(struct seq_file *m, void *v)
 165 {
 166         unsigned long cpu_id = (unsigned long)v - 1;
 167         unsigned int pvr;
 168         unsigned short maj;
 169         unsigned short min;
 170
 171         if (cpu_id == NR_CPUS) {
 172                 struct device_node *root;
 173                 const char *model = NULL;
 174 #if defined(CONFIG_SMP) && defined(CONFIG_PPC32)
 175                 unsigned long bogosum = 0;
 176                 int i;
 177                 for_each_online_cpu(i)
 178                         bogosum += loops_per_jiffy;
 179                 seq_printf(m, "total bogomips\t: %lu.%02lu\n",
 180                            bogosum/(500000/HZ), bogosum/(5000/HZ) % 100);
 181 #endif /* CONFIG_SMP && CONFIG_PPC32 */
 182                 seq_printf(m, "timebase\t: %lu\n", ppc_tb_freq);
 183                 if (ppc_md.name)
 184                         seq_printf(m, "platform\t: %s\n", ppc_md.name);
 185                 root = of_find_node_by_path("/");
 186                 if (root)
 187                         model = of_get_property(root, "model", NULL);
 188                 if (model)
 189                         seq_printf(m, "model\t\t: %s\n", model);
 190                 of_node_put(root);
 191
 192                 if (ppc_md.show_cpuinfo != NULL)
 193                         ppc_md.show_cpuinfo(m);
 194
 195 #ifdef CONFIG_PPC32
 196                 /* Display the amount of memory */
 197                 seq_printf(m, "Memory\t\t: %d MB\n",
 198                            (unsigned int)(total_memory / (1024 * 1024)));
 199 #endif
 200
 201                 return 0;
 202         }
 203
 204         /* We only show online cpus: disable preempt (overzealous, I
 205          * knew) to prevent cpu going down. */
 206         preempt_disable();
 207         if (!cpu_online(cpu_id)) {
 208                 preempt_enable();
 209                 return 0;
 210         }
 211
 212 #ifdef CONFIG_SMP
 213         pvr = per_cpu(cpu_pvr, cpu_id);
 214 #else
 215         pvr = mfspr(SPRN_PVR);
 216 #endif
 217         maj = (pvr >> 8) & 0xFF;
 218         min = pvr & 0xFF;
 219
 220         seq_printf(m, "processor\t: %lu\n", cpu_id);
 221         seq_printf(m, "cpu\t\t: ");
 222
 223         if (cur_cpu_spec->pvr_mask)
 224                 seq_printf(m, "%s", cur_cpu_spec->cpu_name);
 225         else
 226                 seq_printf(m, "unknown (%08x)", pvr);
 227
 228 #ifdef CONFIG_ALTIVEC
 229         if (cpu_has_feature(CPU_FTR_ALTIVEC))
 230                 seq_printf(m, ", altivec supported");
 231 #endif /* CONFIG_ALTIVEC */
 232
 233         seq_printf(m, "\n");
 234
 235 #ifdef CONFIG_TAU
 236         if (cur_cpu_spec->cpu_features & CPU_FTR_TAU) {
 237 #ifdef CONFIG_TAU_AVERAGE
 238                 /* more straightforward, but potentially misleading */
 239                 seq_printf(m,  "temperature \t: %u C (uncalibrated)\n",
 240                            cpu_temp(cpu_id));
 241 #else
 242                 /* show the actual temp sensor range */
 243                 u32 temp;
 244                 temp = cpu_temp_both(cpu_id);
 245                 seq_printf(m, "temperature \t: %u-%u C (uncalibrated)\n",
 246                            temp & 0xff, temp >> 16);
 247 #endif
 248         }
 249 #endif /* CONFIG_TAU */
 250
 251         /*
 252          * Assume here that all clock rates are the same in a
 253          * smp system.  -- Cort
 254          */
 255         if (ppc_proc_freq)
 256                 seq_printf(m, "clock\t\t: %lu.%06luMHz\n",
 257                            ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
 258
 259         if (ppc_md.show_percpuinfo != NULL)
 260                 ppc_md.show_percpuinfo(m, cpu_id);
 261
 262         /* If we are a Freescale core do a simple check so
 263          * we dont have to keep adding cases in the future */
 264         if (PVR_VER(pvr) & 0x8000) {
 265                 switch (PVR_VER(pvr)) {
 266                 case 0x8000:    /* 7441/7450/7451, Voyager */
 267                 case 0x8001:    /* 7445/7455, Apollo 6 */
 268                 case 0x8002:    /* 7447/7457, Apollo 7 */
 269                 case 0x8003:    /* 7447A, Apollo 7 PM */
 270                 case 0x8004:    /* 7448, Apollo 8 */
 271                 case 0x800c:    /* 7410, Nitro */
 272                         maj = ((pvr >> 8) & 0xF);
 273                         min = PVR_MIN(pvr);
 274                         break;
 275                 default:        /* e500/book-e */
 276                         maj = PVR_MAJ(pvr);
 277                         min = PVR_MIN(pvr);
 278                         break;
 279                 }
 280         } else {
 281                 switch (PVR_VER(pvr)) {
 282                         case 0x0020:    /* 403 family */
 283                                 maj = PVR_MAJ(pvr) + 1;
 284                                 min = PVR_MIN(pvr);
 285                                 break;
 286                         case 0x1008:    /* 740P/750P ?? */
 287                                 maj = ((pvr >> 8) & 0xFF) - 1;
 288                                 min = pvr & 0xFF;
 289                                 break;
 290                         default:
 291                                 maj = (pvr >> 8) & 0xFF;
 292                                 min = pvr & 0xFF;
 293                                 break;
 294                 }
 295         }
 296
 297         seq_printf(m, "revision\t: %hd.%hd (pvr %04x %04x)\n",
 298                    maj, min, PVR_VER(pvr), PVR_REV(pvr));
 299
 300 #ifdef CONFIG_PPC32
 301         seq_printf(m, "bogomips\t: %lu.%02lu\n",
 302                    loops_per_jiffy / (500000/HZ),
 303                    (loops_per_jiffy / (5000/HZ)) % 100);
 304 #endif
 305
 306 #ifdef CONFIG_SMP
 307         seq_printf(m, "\n");
 308 #endif
 309
 310         preempt_enable();
 311         return 0;
 312 }
 313
 314 static void *c_start(struct seq_file *m, loff_t *pos)
 315 {
 316         unsigned long i = *pos;
 317
 318         return i <= NR_CPUS ? (void *)(i + 1) : NULL;
 319 }
 320
 321 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 322 {
 323         ++*pos;
 324         return c_start(m, pos);
 325 }
 326
 327 static void c_stop(struct seq_file *m, void *v)
 328 {
 329 }
 330
 331 const struct seq_operations cpuinfo_op = {
 332         .start =c_start,
 333         .next = c_next,
 334         .stop = c_stop,
 335         .show = show_cpuinfo,
 336 };
 337
 338 void __init check_for_initrd(void)
 339 {
 340 #ifdef CONFIG_BLK_DEV_INITRD
 341         DBG(" -> check_for_initrd()  initrd_start=0x%lx  initrd_end=0x%lx\n",
 342             initrd_start, initrd_end);
 343
 344         /* If we were passed an initrd, set the ROOT_DEV properly if the values
 345          * look sensible. If not, clear initrd reference.
 346          */
 347         if (is_kernel_addr(initrd_start) && is_kernel_addr(initrd_end) &&
 348             initrd_end > initrd_start)
 349                 ROOT_DEV = Root_RAM0;
 350         else
 351                 initrd_start = initrd_end = 0;
 352
 353         if (initrd_start)
 354                 printk("Found initrd at 0x%lx:0x%lx\n", initrd_start, initrd_end);
 355
 356         DBG(" <- check_for_initrd()\n");
 357 #endif /* CONFIG_BLK_DEV_INITRD */
 358 }
 359
 360 #ifdef CONFIG_SMP
 361
 362 int threads_per_core, threads_shift;
 363 cpumask_t threads_core_mask;
 364
 365 static void __init cpu_init_thread_core_maps(int tpc)
 366 {
 367         int i;
 368
 369         threads_per_core = tpc;
 370         threads_core_mask = CPU_MASK_NONE;
 371
 372         /* This implementation only supports power of 2 number of threads
 373          * for simplicity and performance
 374          */
 375         threads_shift = ilog2(tpc);
 376         BUG_ON(tpc != (1 << threads_shift));
 377
 378         for (i = 0; i < tpc; i++)
 379                 cpu_set(i, threads_core_mask);
 380
 381         printk(KERN_INFO "CPU maps initialized for %d thread%s per core\n",
 382                tpc, tpc > 1 ? "s" : "");
 383         printk(KERN_DEBUG " (thread shift is %d)\n", threads_shift);
 384 }
 385
 386
 387 /**
 388  * setup_cpu_maps - initialize the following cpu maps:
 389  *                  cpu_possible_map
 390  *                  cpu_present_map
 391  *
 392  * Having the possible map set up early allows us to restrict allocations
 393  * of things like irqstacks to num_possible_cpus() rather than NR_CPUS.
 394  *
 395  * We do not initialize the online map here; cpus set their own bits in
 396  * cpu_online_map as they come up.
 397  *
 398  * This function is valid only for Open Firmware systems.  finish_device_tree
 399  * must be called before using this.
 400  *
 401  * While we're here, we may as well set the "physical" cpu ids in the paca.
 402  *
 403  * NOTE: This must match the parsing done in early_init_dt_scan_cpus.
 404  */
 405 void __init smp_setup_cpu_maps(void)
 406 {
 407         struct device_node *dn = NULL;
 408         int cpu = 0;
 409         int nthreads = 1;
 410
 411         DBG("smp_setup_cpu_maps()\n");
 412
 413         while ((dn = of_find_node_by_type(dn, "cpu")) && cpu < NR_CPUS) {
 414                 const int *intserv;
 415                 int j, len;
 416
 417                 DBG("  * %s...\n", dn->full_name);
 418
 419                 intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s",
 420                                 &len);
 421                 if (intserv) {
 422                         nthreads = len / sizeof(int);
 423                         DBG("    ibm,ppc-interrupt-server#s -> %d threads\n",
 424                             nthreads);
 425                 } else {
 426                         DBG("    no ibm,ppc-interrupt-server#s -> 1 thread\n");
 427                         intserv = of_get_property(dn, "reg", NULL);
 428                         if (!intserv)
 429                                 intserv = &cpu; /* assume logical == phys */
 430                 }
 431
 432                 for (j = 0; j < nthreads && cpu < NR_CPUS; j++) {
 433                         DBG("    thread %d -> cpu %d (hard id %d)\n",
 434                             j, cpu, intserv[j]);
 435                         set_cpu_present(cpu, true);
 436                         set_hard_smp_processor_id(cpu, intserv[j]);
 437                         set_cpu_possible(cpu, true);
 438                         cpu++;
 439                 }
 440         }
 441
 442         /* If no SMT supported, nthreads is forced to 1 */
 443         if (!cpu_has_feature(CPU_FTR_SMT)) {
 444                 DBG("  SMT disabled ! nthreads forced to 1\n");
 445                 nthreads = 1;
 446         }
 447
 448 #ifdef CONFIG_PPC64
 449         /*
 450          * On pSeries LPAR, we need to know how many cpus
 451          * could possibly be added to this partition.
 452          */
 453         if (machine_is(pseries) && firmware_has_feature(FW_FEATURE_LPAR) &&
 454             (dn = of_find_node_by_path("/rtas"))) {
 455                 int num_addr_cell, num_size_cell, maxcpus;
 456                 const unsigned int *ireg;
 457
 458                 num_addr_cell = of_n_addr_cells(dn);
 459                 num_size_cell = of_n_size_cells(dn);
 460
 461                 ireg = of_get_property(dn, "ibm,lrdr-capacity", NULL);
 462
 463                 if (!ireg)
 464                         goto out;
 465
 466                 maxcpus = ireg[num_addr_cell + num_size_cell];
 467
 468                 /* Double maxcpus for processors which have SMT capability */
 469                 if (cpu_has_feature(CPU_FTR_SMT))
 470                         maxcpus *= nthreads;
 471
 472                 if (maxcpus > NR_CPUS) {
 473                         printk(KERN_WARNING
 474                                "Partition configured for %d cpus, "
 475                                "operating system maximum is %d.\n",
 476                                maxcpus, NR_CPUS);
 477                         maxcpus = NR_CPUS;
 478                 } else
 479                         printk(KERN_INFO "Partition configured for %d cpus.\n",
 480                                maxcpus);
 481
 482                 for (cpu = 0; cpu < maxcpus; cpu++)
 483                         set_cpu_possible(cpu, true);
 484         out:
 485                 of_node_put(dn);
 486         }
 487         vdso_data->processorCount = num_present_cpus();
 488 #endif /* CONFIG_PPC64 */
 489
 490         /* Initialize CPU <=> thread mapping/
 491          *
 492          * WARNING: We assume that the number of threads is the same for
 493          * every CPU in the system. If that is not the case, then some code
 494          * here will have to be reworked
 495          */
 496         cpu_init_thread_core_maps(nthreads);
 497
 498         free_unused_pacas();
 499 }
 500 #endif /* CONFIG_SMP */
 501
 502 #ifdef CONFIG_PCSPKR_PLATFORM
 503 static __init int add_pcspkr(void)
 504 {
 505         struct device_node *np;
 506         struct platform_device *pd;
 507         int ret;
 508
 509         np = of_find_compatible_node(NULL, NULL, "pnpPNP,100");
 510         of_node_put(np);
 511         if (!np)
 512                 return -ENODEV;
 513
 514         pd = platform_device_alloc("pcspkr", -1);
 515         if (!pd)
 516                 return -ENOMEM;
 517
 518         ret = platform_device_add(pd);
 519         if (ret)
 520                 platform_device_put(pd);
 521
 522         return ret;
 523 }
 524 device_initcall(add_pcspkr);
 525 #endif  /* CONFIG_PCSPKR_PLATFORM */
 526
 527 void probe_machine(void)
 528 {
 529         extern struct machdep_calls __machine_desc_start;
 530         extern struct machdep_calls __machine_desc_end;
 531
 532         /*
 533          * Iterate all ppc_md structures until we find the proper
 534          * one for the current machine type
 535          */
 536         DBG("Probing machine type ...\n");
 537
 538         for (machine_id = &__machine_desc_start;
 539              machine_id < &__machine_desc_end;
 540              machine_id++) {
 541                 DBG("  %s ...", machine_id->name);
 542                 memcpy(&ppc_md, machine_id, sizeof(struct machdep_calls));
 543                 if (ppc_md.probe()) {
 544                         DBG(" match !\n");
 545                         break;
 546                 }
 547                 DBG("\n");
 548         }
 549         /* What can we do if we didn't find ? */
 550         if (machine_id >= &__machine_desc_end) {
 551                 DBG("No suitable machine found !\n");
 552                 for (;;);
 553         }
 554
 555         printk(KERN_INFO "Using %s machine description\n", ppc_md.name);
 556 }
 557
 558 /* Match a class of boards, not a specific device configuration. */
 559 int check_legacy_ioport(unsigned long base_port)
 560 {
 561         struct device_node *parent, *np = NULL;
 562         int ret = -ENODEV;
 563
 564         switch(base_port) {
 565         case I8042_DATA_REG:
 566                 if (!(np = of_find_compatible_node(NULL, NULL, "pnpPNP,303")))
 567                         np = of_find_compatible_node(NULL, NULL, "pnpPNP,f03");
 568                 if (np) {
 569                         parent = of_get_parent(np);
 570                         of_node_put(np);
 571                         np = parent;
 572                         break;
 573                 }
 574                 np = of_find_node_by_type(NULL, "8042");
 575                 /* Pegasos has no device_type on its 8042 node, look for the
 576                  * name instead */
 577                 if (!np)
 578                         np = of_find_node_by_name(NULL, "8042");
 579                 break;
 580         case FDC_BASE: /* FDC1 */
 581                 np = of_find_node_by_type(NULL, "fdc");
 582                 break;
 583 #ifdef CONFIG_PPC_PREP
 584         case _PIDXR:
 585         case _PNPWRP:
 586         case PNPBIOS_BASE:
 587                 /* implement me */
 588 #endif
 589         default:
 590                 /* ipmi is supposed to fail here */
 591                 break;
 592         }
 593         if (!np)
 594                 return ret;
 595         parent = of_get_parent(np);
 596         if (parent) {
 597                 if (strcmp(parent->type, "isa") == 0)
 598                         ret = 0;
 599                 of_node_put(parent);
 600         }
 601         of_node_put(np);
 602         return ret;
 603 }
 604 EXPORT_SYMBOL(check_legacy_ioport);
 605
 606 static int ppc_panic_event(struct notifier_block *this,
 607                              unsigned long event, void *ptr)
 608 {
 609         ppc_md.panic(ptr);  /* May not return */
 610         return NOTIFY_DONE;
 611 }
 612
 613 static struct notifier_block ppc_panic_block = {
 614         .notifier_call = ppc_panic_event,
 615         .priority = INT_MIN /* may not return; must be done last */
 616 };
 617
 618 void __init setup_panic(void)
 619 {
 620         atomic_notifier_chain_register(&panic_notifier_list, &ppc_panic_block);
 621 }
 622
 623 #ifdef CONFIG_CHECK_CACHE_COHERENCY
 624 /*
 625  * For platforms that have configurable cache-coherency.  This function
 626  * checks that the cache coherency setting of the kernel matches the setting
 627  * left by the firmware, as indicated in the device tree.  Since a mismatch
 628  * will eventually result in DMA failures, we print * and error and call
 629  * BUG() in that case.
 630  */
 631
 632 #ifdef CONFIG_NOT_COHERENT_CACHE
 633 #define KERNEL_COHERENCY        0
 634 #else
 635 #define KERNEL_COHERENCY        1
 636 #endif
 637
 638 static int __init check_cache_coherency(void)
 639 {
 640         struct device_node *np;
 641         const void *prop;
 642         int devtree_coherency;
 643
 644         np = of_find_node_by_path("/");
 645         prop = of_get_property(np, "coherency-off", NULL);
 646         of_node_put(np);
 647
 648         devtree_coherency = prop ? 0 : 1;
 649
 650         if (devtree_coherency != KERNEL_COHERENCY) {
 651                 printk(KERN_ERR
 652                         "kernel coherency:%s != device tree_coherency:%s\n",
 653                         KERNEL_COHERENCY ? "on" : "off",
 654                         devtree_coherency ? "on" : "off");
 655                 BUG();
 656         }
 657
 658         return 0;
 659 }
 660
 661 late_initcall(check_cache_coherency);
 662 #endif /* CONFIG_CHECK_CACHE_COHERENCY */
 663
 664 #ifdef CONFIG_DEBUG_FS
 665 struct dentry *powerpc_debugfs_root;
 666 EXPORT_SYMBOL(powerpc_debugfs_root);
 667
 668 static int powerpc_debugfs_init(void)
 669 {
 670         powerpc_debugfs_root = debugfs_create_dir("powerpc", NULL);
 671
 672         return powerpc_debugfs_root == NULL;
 673 }
 674 arch_initcall(powerpc_debugfs_init);
 675 #endif
 676
 677 static int ppc_dflt_bus_notify(struct notifier_block *nb,
 678                                 unsigned long action, void *data)
 679 {
 680         struct device *dev = data;
 681
 682         /* We are only intereted in device addition */
 683         if (action != BUS_NOTIFY_ADD_DEVICE)
 684                 return 0;
 685
 686         set_dma_ops(dev, &dma_direct_ops);
 687
 688         return NOTIFY_DONE;
 689 }
 690
 691 static struct notifier_block ppc_dflt_plat_bus_notifier = {
 692         .notifier_call = ppc_dflt_bus_notify,
 693         .priority = INT_MAX,
 694 };
 695
 696 static struct notifier_block ppc_dflt_of_bus_notifier = {
 697         .notifier_call = ppc_dflt_bus_notify,
 698         .priority = INT_MAX,
 699 };
 700
 701 static int __init setup_bus_notifier(void)
 702 {
 703         bus_register_notifier(&platform_bus_type, &ppc_dflt_plat_bus_notifier);
 704         bus_register_notifier(&of_platform_bus_type, &ppc_dflt_of_bus_notifier);
 705
 706         return 0;
 707 }
 708
 709 arch_initcall(setup_bus_notifier);