arch/powerpc/platforms/pseries/setup.c

   1 /*
   2  *  64-bit pSeries and RS/6000 setup code.
   3  *
   4  *  Copyright (C) 1995  Linus Torvalds
   5  *  Adapted from 'alpha' version by Gary Thomas
   6  *  Modified by Cort Dougan (cort@cs.nmt.edu)
   7  *  Modified by PPC64 Team, IBM Corp
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version
  12  * 2 of the License, or (at your option) any later version.
  13  */
  14
  15 /*
  16  * bootup setup stuff..
  17  */
  18
  19 #include <linux/cpu.h>
  20 #include <linux/errno.h>
  21 #include <linux/sched.h>
  22 #include <linux/kernel.h>
  23 #include <linux/mm.h>
  24 #include <linux/stddef.h>
  25 #include <linux/unistd.h>
  26 #include <linux/user.h>
  27 #include <linux/tty.h>
  28 #include <linux/major.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/reboot.h>
  31 #include <linux/init.h>
  32 #include <linux/ioport.h>
  33 #include <linux/console.h>
  34 #include <linux/pci.h>
  35 #include <linux/utsname.h>
  36 #include <linux/adb.h>
  37 #include <linux/module.h>
  38 #include <linux/delay.h>
  39 #include <linux/irq.h>
  40 #include <linux/seq_file.h>
  41 #include <linux/root_dev.h>
  42
  43 #include <asm/mmu.h>
  44 #include <asm/processor.h>
  45 #include <asm/io.h>
  46 #include <asm/pgtable.h>
  47 #include <asm/prom.h>
  48 #include <asm/rtas.h>
  49 #include <asm/pci-bridge.h>
  50 #include <asm/iommu.h>
  51 #include <asm/dma.h>
  52 #include <asm/machdep.h>
  53 #include <asm/irq.h>
  54 #include <asm/time.h>
  55 #include <asm/nvram.h>
  56 #include <asm/pmc.h>
  57 #include <asm/mpic.h>
  58 #include <asm/xics.h>
  59 #include <asm/ppc-pci.h>
  60 #include <asm/i8259.h>
  61 #include <asm/udbg.h>
  62 #include <asm/smp.h>
  63 #include <asm/firmware.h>
  64 #include <asm/eeh.h>
  65 #include <asm/pSeries_reconfig.h>
  66
  67 #include "plpar_wrappers.h"
  68 #include "pseries.h"
  69
  70 int CMO_PrPSP = -1;
  71 int CMO_SecPSP = -1;
  72 unsigned long CMO_PageSize = (ASM_CONST(1) << IOMMU_PAGE_SHIFT);
  73 EXPORT_SYMBOL(CMO_PageSize);
  74
  75 int fwnmi_active;  /* TRUE if an FWNMI handler is present */
  76
  77 static void pseries_shared_idle_sleep(void);
  78 static void pseries_dedicated_idle_sleep(void);
  79
  80 static struct device_node *pSeries_mpic_node;
  81
  82 static void pSeries_show_cpuinfo(struct seq_file *m)
  83 {
  84         struct device_node *root;
  85         const char *model = "";
  86
  87         root = of_find_node_by_path("/");
  88         if (root)
  89                 model = of_get_property(root, "model", NULL);
  90         seq_printf(m, "machine\t\t: CHRP %s\n", model);
  91         of_node_put(root);
  92 }
  93
  94 /* Initialize firmware assisted non-maskable interrupts if
  95  * the firmware supports this feature.
  96  */
  97 static void __init fwnmi_init(void)
  98 {
  99         unsigned long system_reset_addr, machine_check_addr;
 100
 101         int ibm_nmi_register = rtas_token("ibm,nmi-register");
 102         if (ibm_nmi_register == RTAS_UNKNOWN_SERVICE)
 103                 return;
 104
 105         /* If the kernel's not linked at zero we point the firmware at low
 106          * addresses anyway, and use a trampoline to get to the real code. */
 107         system_reset_addr  = __pa(system_reset_fwnmi) - PHYSICAL_START;
 108         machine_check_addr = __pa(machine_check_fwnmi) - PHYSICAL_START;
 109
 110         if (0 == rtas_call(ibm_nmi_register, 2, 1, NULL, system_reset_addr,
 111                                 machine_check_addr))
 112                 fwnmi_active = 1;
 113 }
 114
 115 static void pseries_8259_cascade(unsigned int irq, struct irq_desc *desc)
 116 {
 117         struct irq_chip *chip = irq_desc_get_chip(desc);
 118         unsigned int cascade_irq = i8259_irq();
 119
 120         if (cascade_irq != NO_IRQ)
 121                 generic_handle_irq(cascade_irq);
 122
 123         chip->irq_eoi(&desc->irq_data);
 124 }
 125
 126 static void __init pseries_setup_i8259_cascade(void)
 127 {
 128         struct device_node *np, *old, *found = NULL;
 129         unsigned int cascade;
 130         const u32 *addrp;
 131         unsigned long intack = 0;
 132         int naddr;
 133
 134         for_each_node_by_type(np, "interrupt-controller") {
 135                 if (of_device_is_compatible(np, "chrp,iic")) {
 136                         found = np;
 137                         break;
 138                 }
 139         }
 140
 141         if (found == NULL) {
 142                 printk(KERN_DEBUG "pic: no ISA interrupt controller\n");
 143                 return;
 144         }
 145
 146         cascade = irq_of_parse_and_map(found, 0);
 147         if (cascade == NO_IRQ) {
 148                 printk(KERN_ERR "pic: failed to map cascade interrupt");
 149                 return;
 150         }
 151         pr_debug("pic: cascade mapped to irq %d\n", cascade);
 152
 153         for (old = of_node_get(found); old != NULL ; old = np) {
 154                 np = of_get_parent(old);
 155                 of_node_put(old);
 156                 if (np == NULL)
 157                         break;
 158                 if (strcmp(np->name, "pci") != 0)
 159                         continue;
 160                 addrp = of_get_property(np, "8259-interrupt-acknowledge", NULL);
 161                 if (addrp == NULL)
 162                         continue;
 163                 naddr = of_n_addr_cells(np);
 164                 intack = addrp[naddr-1];
 165                 if (naddr > 1)
 166                         intack |= ((unsigned long)addrp[naddr-2]) << 32;
 167         }
 168         if (intack)
 169                 printk(KERN_DEBUG "pic: PCI 8259 intack at 0x%016lx\n", intack);
 170         i8259_init(found, intack);
 171         of_node_put(found);
 172         irq_set_chained_handler(cascade, pseries_8259_cascade);
 173 }
 174
 175 static void __init pseries_mpic_init_IRQ(void)
 176 {
 177         struct device_node *np;
 178         const unsigned int *opprop;
 179         unsigned long openpic_addr = 0;
 180         int naddr, n, i, opplen;
 181         struct mpic *mpic;
 182
 183         np = of_find_node_by_path("/");
 184         naddr = of_n_addr_cells(np);
 185         opprop = of_get_property(np, "platform-open-pic", &opplen);
 186         if (opprop != 0) {
 187                 openpic_addr = of_read_number(opprop, naddr);
 188                 printk(KERN_DEBUG "OpenPIC addr: %lx\n", openpic_addr);
 189         }
 190         of_node_put(np);
 191
 192         BUG_ON(openpic_addr == 0);
 193
 194         /* Setup the openpic driver */
 195         mpic = mpic_alloc(pSeries_mpic_node, openpic_addr,
 196                           MPIC_PRIMARY,
 197                           16, 250, /* isu size, irq count */
 198                           " MPIC     ");
 199         BUG_ON(mpic == NULL);
 200
 201         /* Add ISUs */
 202         opplen /= sizeof(u32);
 203         for (n = 0, i = naddr; i < opplen; i += naddr, n++) {
 204                 unsigned long isuaddr = of_read_number(opprop + i, naddr);
 205                 mpic_assign_isu(mpic, n, isuaddr);
 206         }
 207
 208         /* Setup top-level get_irq */
 209         ppc_md.get_irq = mpic_get_irq;
 210
 211         /* All ISUs are setup, complete initialization */
 212         mpic_init(mpic);
 213
 214         /* Look for cascade */
 215         pseries_setup_i8259_cascade();
 216 }
 217
 218 static void __init pseries_xics_init_IRQ(void)
 219 {
 220         xics_init();
 221         pseries_setup_i8259_cascade();
 222 }
 223
 224 static void pseries_lpar_enable_pmcs(void)
 225 {
 226         unsigned long set, reset;
 227
 228         set = 1UL << 63;
 229         reset = 0;
 230         plpar_hcall_norets(H_PERFMON, set, reset);
 231 }
 232
 233 static void __init pseries_discover_pic(void)
 234 {
 235         struct device_node *np;
 236         const char *typep;
 237
 238         for (np = NULL; (np = of_find_node_by_name(np,
 239                                                    "interrupt-controller"));) {
 240                 typep = of_get_property(np, "compatible", NULL);
 241                 if (strstr(typep, "open-pic")) {
 242                         pSeries_mpic_node = of_node_get(np);
 243                         ppc_md.init_IRQ       = pseries_mpic_init_IRQ;
 244                         setup_kexec_cpu_down_mpic();
 245                         smp_init_pseries_mpic();
 246                         return;
 247                 } else if (strstr(typep, "ppc-xicp")) {
 248                         ppc_md.init_IRQ       = pseries_xics_init_IRQ;
 249                         setup_kexec_cpu_down_xics();
 250                         smp_init_pseries_xics();
 251                         return;
 252                 }
 253         }
 254         printk(KERN_ERR "pSeries_discover_pic: failed to recognize"
 255                " interrupt-controller\n");
 256 }
 257
 258 static int pci_dn_reconfig_notifier(struct notifier_block *nb, unsigned long action, void *node)
 259 {
 260         struct device_node *np = node;
 261         struct pci_dn *pci = NULL;
 262         int err = NOTIFY_OK;
 263
 264         switch (action) {
 265         case PSERIES_RECONFIG_ADD:
 266                 pci = np->parent->data;
 267                 if (pci)
 268                         update_dn_pci_info(np, pci->phb);
 269                 break;
 270         default:
 271                 err = NOTIFY_DONE;
 272                 break;
 273         }
 274         return err;
 275 }
 276
 277 static struct notifier_block pci_dn_reconfig_nb = {
 278         .notifier_call = pci_dn_reconfig_notifier,
 279 };
 280
 281 struct kmem_cache *dtl_cache;
 282
 283 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 284 /*
 285  * Allocate space for the dispatch trace log for all possible cpus
 286  * and register the buffers with the hypervisor.  This is used for
 287  * computing time stolen by the hypervisor.
 288  */
 289 static int alloc_dispatch_logs(void)
 290 {
 291         int cpu, ret;
 292         struct paca_struct *pp;
 293         struct dtl_entry *dtl;
 294
 295         if (!firmware_has_feature(FW_FEATURE_SPLPAR))
 296                 return 0;
 297
 298         if (!dtl_cache)
 299                 return 0;
 300
 301         for_each_possible_cpu(cpu) {
 302                 pp = &paca[cpu];
 303                 dtl = kmem_cache_alloc(dtl_cache, GFP_KERNEL);
 304                 if (!dtl) {
 305                         pr_warn("Failed to allocate dispatch trace log for cpu %d\n",
 306                                 cpu);
 307                         pr_warn("Stolen time statistics will be unreliable\n");
 308                         break;
 309                 }
 310
 311                 pp->dtl_ridx = 0;
 312                 pp->dispatch_log = dtl;
 313                 pp->dispatch_log_end = dtl + N_DISPATCH_LOG;
 314                 pp->dtl_curr = dtl;
 315         }
 316
 317         /* Register the DTL for the current (boot) cpu */
 318         dtl = get_paca()->dispatch_log;
 319         get_paca()->dtl_ridx = 0;
 320         get_paca()->dtl_curr = dtl;
 321         get_paca()->lppaca_ptr->dtl_idx = 0;
 322
 323         /* hypervisor reads buffer length from this field */
 324         dtl->enqueue_to_dispatch_time = DISPATCH_LOG_BYTES;
 325         ret = register_dtl(hard_smp_processor_id(), __pa(dtl));
 326         if (ret)
 327                 pr_warn("DTL registration failed for boot cpu %d (%d)\n",
 328                         smp_processor_id(), ret);
 329         get_paca()->lppaca_ptr->dtl_enable_mask = 2;
 330
 331         return 0;
 332 }
 333 #else /* !CONFIG_VIRT_CPU_ACCOUNTING */
 334 static inline int alloc_dispatch_logs(void)
 335 {
 336         return 0;
 337 }
 338 #endif /* CONFIG_VIRT_CPU_ACCOUNTING */
 339
 340 static int alloc_dispatch_log_kmem_cache(void)
 341 {
 342         dtl_cache = kmem_cache_create("dtl", DISPATCH_LOG_BYTES,
 343                                                 DISPATCH_LOG_BYTES, 0, NULL);
 344         if (!dtl_cache) {
 345                 pr_warn("Failed to create dispatch trace log buffer cache\n");
 346                 pr_warn("Stolen time statistics will be unreliable\n");
 347                 return 0;
 348         }
 349
 350         return alloc_dispatch_logs();
 351 }
 352 early_initcall(alloc_dispatch_log_kmem_cache);
 353
 354 static void __init pSeries_setup_arch(void)
 355 {
 356         /* Discover PIC type and setup ppc_md accordingly */
 357         pseries_discover_pic();
 358
 359         /* openpic global configuration register (64-bit format). */
 360         /* openpic Interrupt Source Unit pointer (64-bit format). */
 361         /* python0 facility area (mmio) (64-bit format) REAL address. */
 362
 363         /* init to some ~sane value until calibrate_delay() runs */
 364         loops_per_jiffy = 50000000;
 365
 366         fwnmi_init();
 367
 368         /* Find and initialize PCI host bridges */
 369         init_pci_config_tokens();
 370         find_and_init_phbs();
 371         pSeries_reconfig_notifier_register(&pci_dn_reconfig_nb);
 372         eeh_init();
 373
 374         pSeries_nvram_init();
 375
 376         /* Choose an idle loop */
 377         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 378                 vpa_init(boot_cpuid);
 379                 if (get_lppaca()->shared_proc) {
 380                         printk(KERN_DEBUG "Using shared processor idle loop\n");
 381                         ppc_md.power_save = pseries_shared_idle_sleep;
 382                 } else {
 383                         printk(KERN_DEBUG "Using dedicated idle loop\n");
 384                         ppc_md.power_save = pseries_dedicated_idle_sleep;
 385                 }
 386         } else {
 387                 printk(KERN_DEBUG "Using default idle loop\n");
 388         }
 389
 390         if (firmware_has_feature(FW_FEATURE_LPAR))
 391                 ppc_md.enable_pmcs = pseries_lpar_enable_pmcs;
 392         else
 393                 ppc_md.enable_pmcs = power4_enable_pmcs;
 394 }
 395
 396 static int __init pSeries_init_panel(void)
 397 {
 398         /* Manually leave the kernel version on the panel. */
 399         ppc_md.progress("Linux ppc64\n", 0);
 400         ppc_md.progress(init_utsname()->version, 0);
 401
 402         return 0;
 403 }
 404 machine_arch_initcall(pseries, pSeries_init_panel);
 405
 406 static int pseries_set_dabr(unsigned long dabr)
 407 {
 408         return plpar_hcall_norets(H_SET_DABR, dabr);
 409 }
 410
 411 static int pseries_set_xdabr(unsigned long dabr)
 412 {
 413         /* We want to catch accesses from kernel and userspace */
 414         return plpar_hcall_norets(H_SET_XDABR, dabr,
 415                         H_DABRX_KERNEL | H_DABRX_USER);
 416 }
 417
 418 #define CMO_CHARACTERISTICS_TOKEN 44
 419 #define CMO_MAXLENGTH 1026
 420
 421 void pSeries_coalesce_init(void)
 422 {
 423         struct hvcall_mpp_x_data mpp_x_data;
 424
 425         if (firmware_has_feature(FW_FEATURE_CMO) && !h_get_mpp_x(&mpp_x_data))
 426                 powerpc_firmware_features |= FW_FEATURE_XCMO;
 427         else
 428                 powerpc_firmware_features &= ~FW_FEATURE_XCMO;
 429 }
 430
 431 /**
 432  * fw_cmo_feature_init - FW_FEATURE_CMO is not stored in ibm,hypertas-functions,
 433  * handle that here. (Stolen from parse_system_parameter_string)
 434  */
 435 void pSeries_cmo_feature_init(void)
 436 {
 437         char *ptr, *key, *value, *end;
 438         int call_status;
 439         int page_order = IOMMU_PAGE_SHIFT;
 440
 441         pr_debug(" -> fw_cmo_feature_init()\n");
 442         spin_lock(&rtas_data_buf_lock);
 443         memset(rtas_data_buf, 0, RTAS_DATA_BUF_SIZE);
 444         call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
 445                                 NULL,
 446                                 CMO_CHARACTERISTICS_TOKEN,
 447                                 __pa(rtas_data_buf),
 448                                 RTAS_DATA_BUF_SIZE);
 449
 450         if (call_status != 0) {
 451                 spin_unlock(&rtas_data_buf_lock);
 452                 pr_debug("CMO not available\n");
 453                 pr_debug(" <- fw_cmo_feature_init()\n");
 454                 return;
 455         }
 456
 457         end = rtas_data_buf + CMO_MAXLENGTH - 2;
 458         ptr = rtas_data_buf + 2;        /* step over strlen value */
 459         key = value = ptr;
 460
 461         while (*ptr && (ptr <= end)) {
 462                 /* Separate the key and value by replacing '=' with '\0' and
 463                  * point the value at the string after the '='
 464                  */
 465                 if (ptr[0] == '=') {
 466                         ptr[0] = '\0';
 467                         value = ptr + 1;
 468                 } else if (ptr[0] == '\0' || ptr[0] == ',') {
 469                         /* Terminate the string containing the key/value pair */
 470                         ptr[0] = '\0';
 471
 472                         if (key == value) {
 473                                 pr_debug("Malformed key/value pair\n");
 474                                 /* Never found a '=', end processing */
 475                                 break;
 476                         }
 477
 478                         if (0 == strcmp(key, "CMOPageSize"))
 479                                 page_order = simple_strtol(value, NULL, 10);
 480                         else if (0 == strcmp(key, "PrPSP"))
 481                                 CMO_PrPSP = simple_strtol(value, NULL, 10);
 482                         else if (0 == strcmp(key, "SecPSP"))
 483                                 CMO_SecPSP = simple_strtol(value, NULL, 10);
 484                         value = key = ptr + 1;
 485                 }
 486                 ptr++;
 487         }
 488
 489         /* Page size is returned as the power of 2 of the page size,
 490          * convert to the page size in bytes before returning
 491          */
 492         CMO_PageSize = 1 << page_order;
 493         pr_debug("CMO_PageSize = %lu\n", CMO_PageSize);
 494
 495         if (CMO_PrPSP != -1 || CMO_SecPSP != -1) {
 496                 pr_info("CMO enabled\n");
 497                 pr_debug("CMO enabled, PrPSP=%d, SecPSP=%d\n", CMO_PrPSP,
 498                          CMO_SecPSP);
 499                 powerpc_firmware_features |= FW_FEATURE_CMO;
 500                 pSeries_coalesce_init();
 501         } else
 502                 pr_debug("CMO not enabled, PrPSP=%d, SecPSP=%d\n", CMO_PrPSP,
 503                          CMO_SecPSP);
 504         spin_unlock(&rtas_data_buf_lock);
 505         pr_debug(" <- fw_cmo_feature_init()\n");
 506 }
 507
 508 /*
 509  * Early initialization.  Relocation is on but do not reference unbolted pages
 510  */
 511 static void __init pSeries_init_early(void)
 512 {
 513         pr_debug(" -> pSeries_init_early()\n");
 514
 515         if (firmware_has_feature(FW_FEATURE_LPAR))
 516                 find_udbg_vterm();
 517
 518         if (firmware_has_feature(FW_FEATURE_DABR))
 519                 ppc_md.set_dabr = pseries_set_dabr;
 520         else if (firmware_has_feature(FW_FEATURE_XDABR))
 521                 ppc_md.set_dabr = pseries_set_xdabr;
 522
 523         pSeries_cmo_feature_init();
 524         iommu_init_early_pSeries();
 525
 526         pr_debug(" <- pSeries_init_early()\n");
 527 }
 528
 529 /*
 530  * Called very early, MMU is off, device-tree isn't unflattened
 531  */
 532
 533 static int __init pSeries_probe_hypertas(unsigned long node,
 534                                          const char *uname, int depth,
 535                                          void *data)
 536 {
 537         const char *hypertas;
 538         unsigned long len;
 539
 540         if (depth != 1 ||
 541             (strcmp(uname, "rtas") != 0 && strcmp(uname, "rtas@0") != 0))
 542                 return 0;
 543
 544         hypertas = of_get_flat_dt_prop(node, "ibm,hypertas-functions", &len);
 545         if (!hypertas)
 546                 return 1;
 547
 548         powerpc_firmware_features |= FW_FEATURE_LPAR;
 549         fw_feature_init(hypertas, len);
 550
 551         return 1;
 552 }
 553
 554 static int __init pSeries_probe(void)
 555 {
 556         unsigned long root = of_get_flat_dt_root();
 557         char *dtype = of_get_flat_dt_prop(root, "device_type", NULL);
 558
 559         if (dtype == NULL)
 560                 return 0;
 561         if (strcmp(dtype, "chrp"))
 562                 return 0;
 563
 564         /* Cell blades firmware claims to be chrp while it's not. Until this
 565          * is fixed, we need to avoid those here.
 566          */
 567         if (of_flat_dt_is_compatible(root, "IBM,CPBW-1.0") ||
 568             of_flat_dt_is_compatible(root, "IBM,CBEA"))
 569                 return 0;
 570
 571         pr_debug("pSeries detected, looking for LPAR capability...\n");
 572
 573         /* Now try to figure out if we are running on LPAR */
 574         of_scan_flat_dt(pSeries_probe_hypertas, NULL);
 575
 576         if (firmware_has_feature(FW_FEATURE_LPAR))
 577                 hpte_init_lpar();
 578         else
 579                 hpte_init_native();
 580
 581         pr_debug("Machine is%s LPAR !\n",
 582                  (powerpc_firmware_features & FW_FEATURE_LPAR) ? "" : " not");
 583
 584         return 1;
 585 }
 586
 587
 588 DECLARE_PER_CPU(long, smt_snooze_delay);
 589
 590 static void pseries_dedicated_idle_sleep(void)
 591 {
 592         unsigned int cpu = smp_processor_id();
 593         unsigned long start_snooze;
 594         unsigned long in_purr, out_purr;
 595         long snooze = __get_cpu_var(smt_snooze_delay);
 596
 597         /*
 598          * Indicate to the HV that we are idle. Now would be
 599          * a good time to find other work to dispatch.
 600          */
 601         get_lppaca()->idle = 1;
 602         get_lppaca()->donate_dedicated_cpu = 1;
 603         in_purr = mfspr(SPRN_PURR);
 604
 605         /*
 606          * We come in with interrupts disabled, and need_resched()
 607          * has been checked recently.  If we should poll for a little
 608          * while, do so.
 609          */
 610         if (snooze) {
 611                 start_snooze = get_tb() + snooze * tb_ticks_per_usec;
 612                 local_irq_enable();
 613                 set_thread_flag(TIF_POLLING_NRFLAG);
 614
 615                 while ((snooze < 0) || (get_tb() < start_snooze)) {
 616                         if (need_resched() || cpu_is_offline(cpu))
 617                                 goto out;
 618                         ppc64_runlatch_off();
 619                         HMT_low();
 620                         HMT_very_low();
 621                 }
 622
 623                 HMT_medium();
 624                 clear_thread_flag(TIF_POLLING_NRFLAG);
 625                 smp_mb();
 626                 local_irq_disable();
 627                 if (need_resched() || cpu_is_offline(cpu))
 628                         goto out;
 629         }
 630
 631         cede_processor();
 632
 633 out:
 634         HMT_medium();
 635         out_purr = mfspr(SPRN_PURR);
 636         get_lppaca()->wait_state_cycles += out_purr - in_purr;
 637         get_lppaca()->donate_dedicated_cpu = 0;
 638         get_lppaca()->idle = 0;
 639 }
 640
 641 static void pseries_shared_idle_sleep(void)
 642 {
 643         /*
 644          * Indicate to the HV that we are idle. Now would be
 645          * a good time to find other work to dispatch.
 646          */
 647         get_lppaca()->idle = 1;
 648
 649         /*
 650          * Yield the processor to the hypervisor.  We return if
 651          * an external interrupt occurs (which are driven prior
 652          * to returning here) or if a prod occurs from another
 653          * processor. When returning here, external interrupts
 654          * are enabled.
 655          */
 656         cede_processor();
 657
 658         get_lppaca()->idle = 0;
 659 }
 660
 661 static int pSeries_pci_probe_mode(struct pci_bus *bus)
 662 {
 663         if (firmware_has_feature(FW_FEATURE_LPAR))
 664                 return PCI_PROBE_DEVTREE;
 665         return PCI_PROBE_NORMAL;
 666 }
 667
 668 /**
 669  * pSeries_power_off - tell firmware about how to power off the system.
 670  *
 671  * This function calls either the power-off rtas token in normal cases
 672  * or the ibm,power-off-ups token (if present & requested) in case of
 673  * a power failure. If power-off token is used, power on will only be
 674  * possible with power button press. If ibm,power-off-ups token is used
 675  * it will allow auto poweron after power is restored.
 676  */
 677 static void pSeries_power_off(void)
 678 {
 679         int rc;
 680         int rtas_poweroff_ups_token = rtas_token("ibm,power-off-ups");
 681
 682         if (rtas_flash_term_hook)
 683                 rtas_flash_term_hook(SYS_POWER_OFF);
 684
 685         if (rtas_poweron_auto == 0 ||
 686                 rtas_poweroff_ups_token == RTAS_UNKNOWN_SERVICE) {
 687                 rc = rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1);
 688                 printk(KERN_INFO "RTAS power-off returned %d\n", rc);
 689         } else {
 690                 rc = rtas_call(rtas_poweroff_ups_token, 0, 1, NULL);
 691                 printk(KERN_INFO "RTAS ibm,power-off-ups returned %d\n", rc);
 692         }
 693         for (;;);
 694 }
 695
 696 #ifndef CONFIG_PCI
 697 void pSeries_final_fixup(void) { }
 698 #endif
 699
 700 define_machine(pseries) {
 701         .name                   = "pSeries",
 702         .probe                  = pSeries_probe,
 703         .setup_arch             = pSeries_setup_arch,
 704         .init_early             = pSeries_init_early,
 705         .show_cpuinfo           = pSeries_show_cpuinfo,
 706         .log_error              = pSeries_log_error,
 707         .pcibios_fixup          = pSeries_final_fixup,
 708         .pci_probe_mode         = pSeries_pci_probe_mode,
 709         .restart                = rtas_restart,
 710         .power_off              = pSeries_power_off,
 711         .halt                   = rtas_halt,
 712         .panic                  = rtas_os_term,
 713         .get_boot_time          = rtas_get_boot_time,
 714         .get_rtc_time           = rtas_get_rtc_time,
 715         .set_rtc_time           = rtas_set_rtc_time,
 716         .calibrate_decr         = generic_calibrate_decr,
 717         .progress               = rtas_progress,
 718         .system_reset_exception = pSeries_system_reset_exception,
 719         .machine_check_exception = pSeries_machine_check_exception,
 720 };