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/memblock.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 /* Variables required to store legacy IO irq routing */ 98 int of_i8042_kbd_irq; 99 EXPORT_SYMBOL_GPL(of_i8042_kbd_irq); 100 int of_i8042_aux_irq; 101 EXPORT_SYMBOL_GPL(of_i8042_aux_irq); 102 103 #ifdef __DO_IRQ_CANON 104 /* XXX should go elsewhere eventually */ 105 int ppc_do_canonicalize_irqs; 106 EXPORT_SYMBOL(ppc_do_canonicalize_irqs); 107 #endif 108 109 /* also used by kexec */ 110 void machine_shutdown(void) 111 { 112 if (ppc_md.machine_shutdown) 113 ppc_md.machine_shutdown(); 114 } 115 116 void machine_restart(char *cmd) 117 { 118 machine_shutdown(); 119 if (ppc_md.restart) 120 ppc_md.restart(cmd); 121 #ifdef CONFIG_SMP 122 smp_send_stop(); 123 #endif 124 printk(KERN_EMERG "System Halted, OK to turn off power\n"); 125 local_irq_disable(); 126 while (1) ; 127 } 128 129 void machine_power_off(void) 130 { 131 machine_shutdown(); 132 if (ppc_md.power_off) 133 ppc_md.power_off(); 134 #ifdef CONFIG_SMP 135 smp_send_stop(); 136 #endif 137 printk(KERN_EMERG "System Halted, OK to turn off power\n"); 138 local_irq_disable(); 139 while (1) ; 140 } 141 /* Used by the G5 thermal driver */ 142 EXPORT_SYMBOL_GPL(machine_power_off); 143 144 void (*pm_power_off)(void) = machine_power_off; 145 EXPORT_SYMBOL_GPL(pm_power_off); 146 147 void machine_halt(void) 148 { 149 machine_shutdown(); 150 if (ppc_md.halt) 151 ppc_md.halt(); 152 #ifdef CONFIG_SMP 153 smp_send_stop(); 154 #endif 155 printk(KERN_EMERG "System Halted, OK to turn off power\n"); 156 local_irq_disable(); 157 while (1) ; 158 } 159 160 161 #ifdef CONFIG_TAU 162 extern u32 cpu_temp(unsigned long cpu); 163 extern u32 cpu_temp_both(unsigned long cpu); 164 #endif /* CONFIG_TAU */ 165 166 #ifdef CONFIG_SMP 167 DEFINE_PER_CPU(unsigned int, cpu_pvr); 168 #endif 169 170 static void show_cpuinfo_summary(struct seq_file *m) 171 { 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 } 201 202 static int show_cpuinfo(struct seq_file *m, void *v) 203 { 204 unsigned long cpu_id = (unsigned long)v - 1; 205 unsigned int pvr; 206 unsigned short maj; 207 unsigned short min; 208 209 /* We only show online cpus: disable preempt (overzealous, I 210 * knew) to prevent cpu going down. */ 211 preempt_disable(); 212 if (!cpu_online(cpu_id)) { 213 preempt_enable(); 214 return 0; 215 } 216 217 #ifdef CONFIG_SMP 218 pvr = per_cpu(cpu_pvr, cpu_id); 219 #else 220 pvr = mfspr(SPRN_PVR); 221 #endif 222 maj = (pvr >> 8) & 0xFF; 223 min = pvr & 0xFF; 224 225 seq_printf(m, "processor\t: %lu\n", cpu_id); 226 seq_printf(m, "cpu\t\t: "); 227 228 if (cur_cpu_spec->pvr_mask) 229 seq_printf(m, "%s", cur_cpu_spec->cpu_name); 230 else 231 seq_printf(m, "unknown (%08x)", pvr); 232 233 #ifdef CONFIG_ALTIVEC 234 if (cpu_has_feature(CPU_FTR_ALTIVEC)) 235 seq_printf(m, ", altivec supported"); 236 #endif /* CONFIG_ALTIVEC */ 237 238 seq_printf(m, "\n"); 239 240 #ifdef CONFIG_TAU 241 if (cur_cpu_spec->cpu_features & CPU_FTR_TAU) { 242 #ifdef CONFIG_TAU_AVERAGE 243 /* more straightforward, but potentially misleading */ 244 seq_printf(m, "temperature \t: %u C (uncalibrated)\n", 245 cpu_temp(cpu_id)); 246 #else 247 /* show the actual temp sensor range */ 248 u32 temp; 249 temp = cpu_temp_both(cpu_id); 250 seq_printf(m, "temperature \t: %u-%u C (uncalibrated)\n", 251 temp & 0xff, temp >> 16); 252 #endif 253 } 254 #endif /* CONFIG_TAU */ 255 256 /* 257 * Assume here that all clock rates are the same in a 258 * smp system. -- Cort 259 */ 260 if (ppc_proc_freq) 261 seq_printf(m, "clock\t\t: %lu.%06luMHz\n", 262 ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); 263 264 if (ppc_md.show_percpuinfo != NULL) 265 ppc_md.show_percpuinfo(m, cpu_id); 266 267 /* If we are a Freescale core do a simple check so 268 * we dont have to keep adding cases in the future */ 269 if (PVR_VER(pvr) & 0x8000) { 270 switch (PVR_VER(pvr)) { 271 case 0x8000: /* 7441/7450/7451, Voyager */ 272 case 0x8001: /* 7445/7455, Apollo 6 */ 273 case 0x8002: /* 7447/7457, Apollo 7 */ 274 case 0x8003: /* 7447A, Apollo 7 PM */ 275 case 0x8004: /* 7448, Apollo 8 */ 276 case 0x800c: /* 7410, Nitro */ 277 maj = ((pvr >> 8) & 0xF); 278 min = PVR_MIN(pvr); 279 break; 280 default: /* e500/book-e */ 281 maj = PVR_MAJ(pvr); 282 min = PVR_MIN(pvr); 283 break; 284 } 285 } else { 286 switch (PVR_VER(pvr)) { 287 case 0x0020: /* 403 family */ 288 maj = PVR_MAJ(pvr) + 1; 289 min = PVR_MIN(pvr); 290 break; 291 case 0x1008: /* 740P/750P ?? */ 292 maj = ((pvr >> 8) & 0xFF) - 1; 293 min = pvr & 0xFF; 294 break; 295 default: 296 maj = (pvr >> 8) & 0xFF; 297 min = pvr & 0xFF; 298 break; 299 } 300 } 301 302 seq_printf(m, "revision\t: %hd.%hd (pvr %04x %04x)\n", 303 maj, min, PVR_VER(pvr), PVR_REV(pvr)); 304 305 #ifdef CONFIG_PPC32 306 seq_printf(m, "bogomips\t: %lu.%02lu\n", 307 loops_per_jiffy / (500000/HZ), 308 (loops_per_jiffy / (5000/HZ)) % 100); 309 #endif 310 311 #ifdef CONFIG_SMP 312 seq_printf(m, "\n"); 313 #endif 314 315 preempt_enable(); 316 317 /* If this is the last cpu, print the summary */ 318 if (cpumask_next(cpu_id, cpu_online_mask) >= nr_cpu_ids) 319 show_cpuinfo_summary(m); 320 321 return 0; 322 } 323 324 static void *c_start(struct seq_file *m, loff_t *pos) 325 { 326 if (*pos == 0) /* just in case, cpu 0 is not the first */ 327 *pos = cpumask_first(cpu_online_mask); 328 else 329 *pos = cpumask_next(*pos - 1, cpu_online_mask); 330 if ((*pos) < nr_cpu_ids) 331 return (void *)(unsigned long)(*pos + 1); 332 return NULL; 333 } 334 335 static void *c_next(struct seq_file *m, void *v, loff_t *pos) 336 { 337 (*pos)++; 338 return c_start(m, pos); 339 } 340 341 static void c_stop(struct seq_file *m, void *v) 342 { 343 } 344 345 const struct seq_operations cpuinfo_op = { 346 .start =c_start, 347 .next = c_next, 348 .stop = c_stop, 349 .show = show_cpuinfo, 350 }; 351 352 void __init check_for_initrd(void) 353 { 354 #ifdef CONFIG_BLK_DEV_INITRD 355 DBG(" -> check_for_initrd() initrd_start=0x%lx initrd_end=0x%lx\n", 356 initrd_start, initrd_end); 357 358 /* If we were passed an initrd, set the ROOT_DEV properly if the values 359 * look sensible. If not, clear initrd reference. 360 */ 361 if (is_kernel_addr(initrd_start) && is_kernel_addr(initrd_end) && 362 initrd_end > initrd_start) 363 ROOT_DEV = Root_RAM0; 364 else 365 initrd_start = initrd_end = 0; 366 367 if (initrd_start) 368 printk("Found initrd at 0x%lx:0x%lx\n", initrd_start, initrd_end); 369 370 DBG(" <- check_for_initrd()\n"); 371 #endif /* CONFIG_BLK_DEV_INITRD */ 372 } 373 374 #ifdef CONFIG_SMP 375 376 int threads_per_core, threads_shift; 377 cpumask_t threads_core_mask; 378 379 static void __init cpu_init_thread_core_maps(int tpc) 380 { 381 int i; 382 383 threads_per_core = tpc; 384 threads_core_mask = CPU_MASK_NONE; 385 386 /* This implementation only supports power of 2 number of threads 387 * for simplicity and performance 388 */ 389 threads_shift = ilog2(tpc); 390 BUG_ON(tpc != (1 << threads_shift)); 391 392 for (i = 0; i < tpc; i++) 393 cpu_set(i, threads_core_mask); 394 395 printk(KERN_INFO "CPU maps initialized for %d thread%s per core\n", 396 tpc, tpc > 1 ? "s" : ""); 397 printk(KERN_DEBUG " (thread shift is %d)\n", threads_shift); 398 } 399 400 401 /** 402 * setup_cpu_maps - initialize the following cpu maps: 403 * cpu_possible_mask 404 * cpu_present_mask 405 * 406 * Having the possible map set up early allows us to restrict allocations 407 * of things like irqstacks to num_possible_cpus() rather than NR_CPUS. 408 * 409 * We do not initialize the online map here; cpus set their own bits in 410 * cpu_online_mask as they come up. 411 * 412 * This function is valid only for Open Firmware systems. finish_device_tree 413 * must be called before using this. 414 * 415 * While we're here, we may as well set the "physical" cpu ids in the paca. 416 * 417 * NOTE: This must match the parsing done in early_init_dt_scan_cpus. 418 */ 419 void __init smp_setup_cpu_maps(void) 420 { 421 struct device_node *dn = NULL; 422 int cpu = 0; 423 int nthreads = 1; 424 425 DBG("smp_setup_cpu_maps()\n"); 426 427 while ((dn = of_find_node_by_type(dn, "cpu")) && cpu < NR_CPUS) { 428 const int *intserv; 429 int j, len; 430 431 DBG(" * %s...\n", dn->full_name); 432 433 intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", 434 &len); 435 if (intserv) { 436 nthreads = len / sizeof(int); 437 DBG(" ibm,ppc-interrupt-server#s -> %d threads\n", 438 nthreads); 439 } else { 440 DBG(" no ibm,ppc-interrupt-server#s -> 1 thread\n"); 441 intserv = of_get_property(dn, "reg", NULL); 442 if (!intserv) 443 intserv = &cpu; /* assume logical == phys */ 444 } 445 446 for (j = 0; j < nthreads && cpu < NR_CPUS; j++) { 447 DBG(" thread %d -> cpu %d (hard id %d)\n", 448 j, cpu, intserv[j]); 449 set_cpu_present(cpu, true); 450 set_hard_smp_processor_id(cpu, intserv[j]); 451 set_cpu_possible(cpu, true); 452 cpu++; 453 } 454 } 455 456 /* If no SMT supported, nthreads is forced to 1 */ 457 if (!cpu_has_feature(CPU_FTR_SMT)) { 458 DBG(" SMT disabled ! nthreads forced to 1\n"); 459 nthreads = 1; 460 } 461 462 #ifdef CONFIG_PPC64 463 /* 464 * On pSeries LPAR, we need to know how many cpus 465 * could possibly be added to this partition. 466 */ 467 if (machine_is(pseries) && firmware_has_feature(FW_FEATURE_LPAR) && 468 (dn = of_find_node_by_path("/rtas"))) { 469 int num_addr_cell, num_size_cell, maxcpus; 470 const unsigned int *ireg; 471 472 num_addr_cell = of_n_addr_cells(dn); 473 num_size_cell = of_n_size_cells(dn); 474 475 ireg = of_get_property(dn, "ibm,lrdr-capacity", NULL); 476 477 if (!ireg) 478 goto out; 479 480 maxcpus = ireg[num_addr_cell + num_size_cell]; 481 482 /* Double maxcpus for processors which have SMT capability */ 483 if (cpu_has_feature(CPU_FTR_SMT)) 484 maxcpus *= nthreads; 485 486 if (maxcpus > NR_CPUS) { 487 printk(KERN_WARNING 488 "Partition configured for %d cpus, " 489 "operating system maximum is %d.\n", 490 maxcpus, NR_CPUS); 491 maxcpus = NR_CPUS; 492 } else 493 printk(KERN_INFO "Partition configured for %d cpus.\n", 494 maxcpus); 495 496 for (cpu = 0; cpu < maxcpus; cpu++) 497 set_cpu_possible(cpu, true); 498 out: 499 of_node_put(dn); 500 } 501 vdso_data->processorCount = num_present_cpus(); 502 #endif /* CONFIG_PPC64 */ 503 504 /* Initialize CPU <=> thread mapping/ 505 * 506 * WARNING: We assume that the number of threads is the same for 507 * every CPU in the system. If that is not the case, then some code 508 * here will have to be reworked 509 */ 510 cpu_init_thread_core_maps(nthreads); 511 512 free_unused_pacas(); 513 } 514 #endif /* CONFIG_SMP */ 515 516 #ifdef CONFIG_PCSPKR_PLATFORM 517 static __init int add_pcspkr(void) 518 { 519 struct device_node *np; 520 struct platform_device *pd; 521 int ret; 522 523 np = of_find_compatible_node(NULL, NULL, "pnpPNP,100"); 524 of_node_put(np); 525 if (!np) 526 return -ENODEV; 527 528 pd = platform_device_alloc("pcspkr", -1); 529 if (!pd) 530 return -ENOMEM; 531 532 ret = platform_device_add(pd); 533 if (ret) 534 platform_device_put(pd); 535 536 return ret; 537 } 538 device_initcall(add_pcspkr); 539 #endif /* CONFIG_PCSPKR_PLATFORM */ 540 541 void probe_machine(void) 542 { 543 extern struct machdep_calls __machine_desc_start; 544 extern struct machdep_calls __machine_desc_end; 545 546 /* 547 * Iterate all ppc_md structures until we find the proper 548 * one for the current machine type 549 */ 550 DBG("Probing machine type ...\n"); 551 552 for (machine_id = &__machine_desc_start; 553 machine_id < &__machine_desc_end; 554 machine_id++) { 555 DBG(" %s ...", machine_id->name); 556 memcpy(&ppc_md, machine_id, sizeof(struct machdep_calls)); 557 if (ppc_md.probe()) { 558 DBG(" match !\n"); 559 break; 560 } 561 DBG("\n"); 562 } 563 /* What can we do if we didn't find ? */ 564 if (machine_id >= &__machine_desc_end) { 565 DBG("No suitable machine found !\n"); 566 for (;;); 567 } 568 569 printk(KERN_INFO "Using %s machine description\n", ppc_md.name); 570 } 571 572 /* Match a class of boards, not a specific device configuration. */ 573 int check_legacy_ioport(unsigned long base_port) 574 { 575 struct device_node *parent, *np = NULL; 576 int ret = -ENODEV; 577 578 switch(base_port) { 579 case I8042_DATA_REG: 580 if (!(np = of_find_compatible_node(NULL, NULL, "pnpPNP,303"))) 581 np = of_find_compatible_node(NULL, NULL, "pnpPNP,f03"); 582 if (np) { 583 parent = of_get_parent(np); 584 585 of_i8042_kbd_irq = irq_of_parse_and_map(parent, 0); 586 if (!of_i8042_kbd_irq) 587 of_i8042_kbd_irq = 1; 588 589 of_i8042_aux_irq = irq_of_parse_and_map(parent, 1); 590 if (!of_i8042_aux_irq) 591 of_i8042_aux_irq = 12; 592 593 of_node_put(np); 594 np = parent; 595 break; 596 } 597 np = of_find_node_by_type(NULL, "8042"); 598 /* Pegasos has no device_type on its 8042 node, look for the 599 * name instead */ 600 if (!np) 601 np = of_find_node_by_name(NULL, "8042"); 602 break; 603 case FDC_BASE: /* FDC1 */ 604 np = of_find_node_by_type(NULL, "fdc"); 605 break; 606 #ifdef CONFIG_PPC_PREP 607 case _PIDXR: 608 case _PNPWRP: 609 case PNPBIOS_BASE: 610 /* implement me */ 611 #endif 612 default: 613 /* ipmi is supposed to fail here */ 614 break; 615 } 616 if (!np) 617 return ret; 618 parent = of_get_parent(np); 619 if (parent) { 620 if (strcmp(parent->type, "isa") == 0) 621 ret = 0; 622 of_node_put(parent); 623 } 624 of_node_put(np); 625 return ret; 626 } 627 EXPORT_SYMBOL(check_legacy_ioport); 628 629 static int ppc_panic_event(struct notifier_block *this, 630 unsigned long event, void *ptr) 631 { 632 ppc_md.panic(ptr); /* May not return */ 633 return NOTIFY_DONE; 634 } 635 636 static struct notifier_block ppc_panic_block = { 637 .notifier_call = ppc_panic_event, 638 .priority = INT_MIN /* may not return; must be done last */ 639 }; 640 641 void __init setup_panic(void) 642 { 643 atomic_notifier_chain_register(&panic_notifier_list, &ppc_panic_block); 644 } 645 646 #ifdef CONFIG_CHECK_CACHE_COHERENCY 647 /* 648 * For platforms that have configurable cache-coherency. This function 649 * checks that the cache coherency setting of the kernel matches the setting 650 * left by the firmware, as indicated in the device tree. Since a mismatch 651 * will eventually result in DMA failures, we print * and error and call 652 * BUG() in that case. 653 */ 654 655 #ifdef CONFIG_NOT_COHERENT_CACHE 656 #define KERNEL_COHERENCY 0 657 #else 658 #define KERNEL_COHERENCY 1 659 #endif 660 661 static int __init check_cache_coherency(void) 662 { 663 struct device_node *np; 664 const void *prop; 665 int devtree_coherency; 666 667 np = of_find_node_by_path("/"); 668 prop = of_get_property(np, "coherency-off", NULL); 669 of_node_put(np); 670 671 devtree_coherency = prop ? 0 : 1; 672 673 if (devtree_coherency != KERNEL_COHERENCY) { 674 printk(KERN_ERR 675 "kernel coherency:%s != device tree_coherency:%s\n", 676 KERNEL_COHERENCY ? "on" : "off", 677 devtree_coherency ? "on" : "off"); 678 BUG(); 679 } 680 681 return 0; 682 } 683 684 late_initcall(check_cache_coherency); 685 #endif /* CONFIG_CHECK_CACHE_COHERENCY */ 686 687 #ifdef CONFIG_DEBUG_FS 688 struct dentry *powerpc_debugfs_root; 689 EXPORT_SYMBOL(powerpc_debugfs_root); 690 691 static int powerpc_debugfs_init(void) 692 { 693 powerpc_debugfs_root = debugfs_create_dir("powerpc", NULL); 694 695 return powerpc_debugfs_root == NULL; 696 } 697 arch_initcall(powerpc_debugfs_init); 698 #endif 699 700 static int ppc_dflt_bus_notify(struct notifier_block *nb, 701 unsigned long action, void *data) 702 { 703 struct device *dev = data; 704 705 /* We are only intereted in device addition */ 706 if (action != BUS_NOTIFY_ADD_DEVICE) 707 return 0; 708 709 set_dma_ops(dev, &dma_direct_ops); 710 711 return NOTIFY_DONE; 712 } 713 714 static struct notifier_block ppc_dflt_plat_bus_notifier = { 715 .notifier_call = ppc_dflt_bus_notify, 716 .priority = INT_MAX, 717 }; 718 719 static int __init setup_bus_notifier(void) 720 { 721 bus_register_notifier(&platform_bus_type, &ppc_dflt_plat_bus_notifier); 722 return 0; 723 } 724 725 arch_initcall(setup_bus_notifier); 726