arch/ia64/xen/irq_xen.c

   1 /******************************************************************************
   2  * arch/ia64/xen/irq_xen.c
   3  *
   4  * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
   5  *                    VA Linux Systems Japan K.K.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  */
  22
  23 #include <linux/cpu.h>
  24
  25 #include <xen/interface/xen.h>
  26 #include <xen/interface/callback.h>
  27 #include <xen/events.h>
  28
  29 #include <asm/xen/privop.h>
  30
  31 #include "irq_xen.h"
  32
  33 /***************************************************************************
  34  * pv_irq_ops
  35  * irq operations
  36  */
  37
  38 static int
  39 xen_assign_irq_vector(int irq)
  40 {
  41         struct physdev_irq irq_op;
  42
  43         irq_op.irq = irq;
  44         if (HYPERVISOR_physdev_op(PHYSDEVOP_alloc_irq_vector, &irq_op))
  45                 return -ENOSPC;
  46
  47         return irq_op.vector;
  48 }
  49
  50 static void
  51 xen_free_irq_vector(int vector)
  52 {
  53         struct physdev_irq irq_op;
  54
  55         if (vector < IA64_FIRST_DEVICE_VECTOR ||
  56             vector > IA64_LAST_DEVICE_VECTOR)
  57                 return;
  58
  59         irq_op.vector = vector;
  60         if (HYPERVISOR_physdev_op(PHYSDEVOP_free_irq_vector, &irq_op))
  61                 printk(KERN_WARNING "%s: xen_free_irq_vecotr fail vector=%d\n",
  62                        __func__, vector);
  63 }
  64
  65
  66 static DEFINE_PER_CPU(int, xen_timer_irq) = -1;
  67 static DEFINE_PER_CPU(int, xen_ipi_irq) = -1;
  68 static DEFINE_PER_CPU(int, xen_resched_irq) = -1;
  69 static DEFINE_PER_CPU(int, xen_cmc_irq) = -1;
  70 static DEFINE_PER_CPU(int, xen_cmcp_irq) = -1;
  71 static DEFINE_PER_CPU(int, xen_cpep_irq) = -1;
  72 #define NAME_SIZE       15
  73 static DEFINE_PER_CPU(char[NAME_SIZE], xen_timer_name);
  74 static DEFINE_PER_CPU(char[NAME_SIZE], xen_ipi_name);
  75 static DEFINE_PER_CPU(char[NAME_SIZE], xen_resched_name);
  76 static DEFINE_PER_CPU(char[NAME_SIZE], xen_cmc_name);
  77 static DEFINE_PER_CPU(char[NAME_SIZE], xen_cmcp_name);
  78 static DEFINE_PER_CPU(char[NAME_SIZE], xen_cpep_name);
  79 #undef NAME_SIZE
  80
  81 struct saved_irq {
  82         unsigned int irq;
  83         struct irqaction *action;
  84 };
  85 /* 16 should be far optimistic value, since only several percpu irqs
  86  * are registered early.
  87  */
  88 #define MAX_LATE_IRQ    16
  89 static struct saved_irq saved_percpu_irqs[MAX_LATE_IRQ];
  90 static unsigned short late_irq_cnt;
  91 static unsigned short saved_irq_cnt;
  92 static int xen_slab_ready;
  93
  94 #ifdef CONFIG_SMP
  95 /* Dummy stub. Though we may check XEN_RESCHEDULE_VECTOR before __do_IRQ,
  96  * it ends up to issue several memory accesses upon percpu data and
  97  * thus adds unnecessary traffic to other paths.
  98  */
  99 static irqreturn_t
 100 xen_dummy_handler(int irq, void *dev_id)
 101 {
 102
 103         return IRQ_HANDLED;
 104 }
 105
 106 static struct irqaction xen_ipi_irqaction = {
 107         .handler =      handle_IPI,
 108         .flags =        IRQF_DISABLED,
 109         .name =         "IPI"
 110 };
 111
 112 static struct irqaction xen_resched_irqaction = {
 113         .handler =      xen_dummy_handler,
 114         .flags =        IRQF_DISABLED,
 115         .name =         "resched"
 116 };
 117
 118 static struct irqaction xen_tlb_irqaction = {
 119         .handler =      xen_dummy_handler,
 120         .flags =        IRQF_DISABLED,
 121         .name =         "tlb_flush"
 122 };
 123 #endif
 124
 125 /*
 126  * This is xen version percpu irq registration, which needs bind
 127  * to xen specific evtchn sub-system. One trick here is that xen
 128  * evtchn binding interface depends on kmalloc because related
 129  * port needs to be freed at device/cpu down. So we cache the
 130  * registration on BSP before slab is ready and then deal them
 131  * at later point. For rest instances happening after slab ready,
 132  * we hook them to xen evtchn immediately.
 133  *
 134  * FIXME: MCA is not supported by far, and thus "nomca" boot param is
 135  * required.
 136  */
 137 static void
 138 __xen_register_percpu_irq(unsigned int cpu, unsigned int vec,
 139                         struct irqaction *action, int save)
 140 {
 141         int irq = 0;
 142
 143         if (xen_slab_ready) {
 144                 switch (vec) {
 145                 case IA64_TIMER_VECTOR:
 146                         snprintf(per_cpu(xen_timer_name, cpu),
 147                                  sizeof(per_cpu(xen_timer_name, cpu)),
 148                                  "%s%d", action->name, cpu);
 149                         irq = bind_virq_to_irqhandler(VIRQ_ITC, cpu,
 150                                 action->handler, action->flags,
 151                                 per_cpu(xen_timer_name, cpu), action->dev_id);
 152                         per_cpu(xen_timer_irq, cpu) = irq;
 153                         break;
 154                 case IA64_IPI_RESCHEDULE:
 155                         snprintf(per_cpu(xen_resched_name, cpu),
 156                                  sizeof(per_cpu(xen_resched_name, cpu)),
 157                                  "%s%d", action->name, cpu);
 158                         irq = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR, cpu,
 159                                 action->handler, action->flags,
 160                                 per_cpu(xen_resched_name, cpu), action->dev_id);
 161                         per_cpu(xen_resched_irq, cpu) = irq;
 162                         break;
 163                 case IA64_IPI_VECTOR:
 164                         snprintf(per_cpu(xen_ipi_name, cpu),
 165                                  sizeof(per_cpu(xen_ipi_name, cpu)),
 166                                  "%s%d", action->name, cpu);
 167                         irq = bind_ipi_to_irqhandler(XEN_IPI_VECTOR, cpu,
 168                                 action->handler, action->flags,
 169                                 per_cpu(xen_ipi_name, cpu), action->dev_id);
 170                         per_cpu(xen_ipi_irq, cpu) = irq;
 171                         break;
 172                 case IA64_CMC_VECTOR:
 173                         snprintf(per_cpu(xen_cmc_name, cpu),
 174                                  sizeof(per_cpu(xen_cmc_name, cpu)),
 175                                  "%s%d", action->name, cpu);
 176                         irq = bind_virq_to_irqhandler(VIRQ_MCA_CMC, cpu,
 177                                                 action->handler,
 178                                                 action->flags,
 179                                                 per_cpu(xen_cmc_name, cpu),
 180                                                 action->dev_id);
 181                         per_cpu(xen_cmc_irq, cpu) = irq;
 182                         break;
 183                 case IA64_CMCP_VECTOR:
 184                         snprintf(per_cpu(xen_cmcp_name, cpu),
 185                                  sizeof(per_cpu(xen_cmcp_name, cpu)),
 186                                  "%s%d", action->name, cpu);
 187                         irq = bind_ipi_to_irqhandler(XEN_CMCP_VECTOR, cpu,
 188                                                 action->handler,
 189                                                 action->flags,
 190                                                 per_cpu(xen_cmcp_name, cpu),
 191                                                 action->dev_id);
 192                         per_cpu(xen_cmcp_irq, cpu) = irq;
 193                         break;
 194                 case IA64_CPEP_VECTOR:
 195                         snprintf(per_cpu(xen_cpep_name, cpu),
 196                                  sizeof(per_cpu(xen_cpep_name, cpu)),
 197                                  "%s%d", action->name, cpu);
 198                         irq = bind_ipi_to_irqhandler(XEN_CPEP_VECTOR, cpu,
 199                                                 action->handler,
 200                                                 action->flags,
 201                                                 per_cpu(xen_cpep_name, cpu),
 202                                                 action->dev_id);
 203                         per_cpu(xen_cpep_irq, cpu) = irq;
 204                         break;
 205                 case IA64_CPE_VECTOR:
 206                 case IA64_MCA_RENDEZ_VECTOR:
 207                 case IA64_PERFMON_VECTOR:
 208                 case IA64_MCA_WAKEUP_VECTOR:
 209                 case IA64_SPURIOUS_INT_VECTOR:
 210                         /* No need to complain, these aren't supported. */
 211                         break;
 212                 default:
 213                         printk(KERN_WARNING "Percpu irq %d is unsupported "
 214                                "by xen!\n", vec);
 215                         break;
 216                 }
 217                 BUG_ON(irq < 0);
 218
 219                 if (irq > 0) {
 220                         /*
 221                          * Mark percpu.  Without this, migrate_irqs() will
 222                          * mark the interrupt for migrations and trigger it
 223                          * on cpu hotplug.
 224                          */
 225                         irq_set_status_flags(irq, IRQ_PER_CPU);
 226                 }
 227         }
 228
 229         /* For BSP, we cache registered percpu irqs, and then re-walk
 230          * them when initializing APs
 231          */
 232         if (!cpu && save) {
 233                 BUG_ON(saved_irq_cnt == MAX_LATE_IRQ);
 234                 saved_percpu_irqs[saved_irq_cnt].irq = vec;
 235                 saved_percpu_irqs[saved_irq_cnt].action = action;
 236                 saved_irq_cnt++;
 237                 if (!xen_slab_ready)
 238                         late_irq_cnt++;
 239         }
 240 }
 241
 242 static void
 243 xen_register_percpu_irq(ia64_vector vec, struct irqaction *action)
 244 {
 245         __xen_register_percpu_irq(smp_processor_id(), vec, action, 1);
 246 }
 247
 248 static void
 249 xen_bind_early_percpu_irq(void)
 250 {
 251         int i;
 252
 253         xen_slab_ready = 1;
 254         /* There's no race when accessing this cached array, since only
 255          * BSP will face with such step shortly
 256          */
 257         for (i = 0; i < late_irq_cnt; i++)
 258                 __xen_register_percpu_irq(smp_processor_id(),
 259                                           saved_percpu_irqs[i].irq,
 260                                           saved_percpu_irqs[i].action, 0);
 261 }
 262
 263 /* FIXME: There's no obvious point to check whether slab is ready. So
 264  * a hack is used here by utilizing a late time hook.
 265  */
 266
 267 #ifdef CONFIG_HOTPLUG_CPU
 268 static int __devinit
 269 unbind_evtchn_callback(struct notifier_block *nfb,
 270                        unsigned long action, void *hcpu)
 271 {
 272         unsigned int cpu = (unsigned long)hcpu;
 273
 274         if (action == CPU_DEAD) {
 275                 /* Unregister evtchn.  */
 276                 if (per_cpu(xen_cpep_irq, cpu) >= 0) {
 277                         unbind_from_irqhandler(per_cpu(xen_cpep_irq, cpu),
 278                                                NULL);
 279                         per_cpu(xen_cpep_irq, cpu) = -1;
 280                 }
 281                 if (per_cpu(xen_cmcp_irq, cpu) >= 0) {
 282                         unbind_from_irqhandler(per_cpu(xen_cmcp_irq, cpu),
 283                                                NULL);
 284                         per_cpu(xen_cmcp_irq, cpu) = -1;
 285                 }
 286                 if (per_cpu(xen_cmc_irq, cpu) >= 0) {
 287                         unbind_from_irqhandler(per_cpu(xen_cmc_irq, cpu), NULL);
 288                         per_cpu(xen_cmc_irq, cpu) = -1;
 289                 }
 290                 if (per_cpu(xen_ipi_irq, cpu) >= 0) {
 291                         unbind_from_irqhandler(per_cpu(xen_ipi_irq, cpu), NULL);
 292                         per_cpu(xen_ipi_irq, cpu) = -1;
 293                 }
 294                 if (per_cpu(xen_resched_irq, cpu) >= 0) {
 295                         unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu),
 296                                                NULL);
 297                         per_cpu(xen_resched_irq, cpu) = -1;
 298                 }
 299                 if (per_cpu(xen_timer_irq, cpu) >= 0) {
 300                         unbind_from_irqhandler(per_cpu(xen_timer_irq, cpu),
 301                                                NULL);
 302                         per_cpu(xen_timer_irq, cpu) = -1;
 303                 }
 304         }
 305         return NOTIFY_OK;
 306 }
 307
 308 static struct notifier_block unbind_evtchn_notifier = {
 309         .notifier_call = unbind_evtchn_callback,
 310         .priority = 0
 311 };
 312 #endif
 313
 314 void xen_smp_intr_init_early(unsigned int cpu)
 315 {
 316 #ifdef CONFIG_SMP
 317         unsigned int i;
 318
 319         for (i = 0; i < saved_irq_cnt; i++)
 320                 __xen_register_percpu_irq(cpu, saved_percpu_irqs[i].irq,
 321                                           saved_percpu_irqs[i].action, 0);
 322 #endif
 323 }
 324
 325 void xen_smp_intr_init(void)
 326 {
 327 #ifdef CONFIG_SMP
 328         unsigned int cpu = smp_processor_id();
 329         struct callback_register event = {
 330                 .type = CALLBACKTYPE_event,
 331                 .address = { .ip = (unsigned long)&xen_event_callback },
 332         };
 333
 334         if (cpu == 0) {
 335                 /* Initialization was already done for boot cpu.  */
 336 #ifdef CONFIG_HOTPLUG_CPU
 337                 /* Register the notifier only once.  */
 338                 register_cpu_notifier(&unbind_evtchn_notifier);
 339 #endif
 340                 return;
 341         }
 342
 343         /* This should be piggyback when setup vcpu guest context */
 344         BUG_ON(HYPERVISOR_callback_op(CALLBACKOP_register, &event));
 345 #endif /* CONFIG_SMP */
 346 }
 347
 348 void __init
 349 xen_irq_init(void)
 350 {
 351         struct callback_register event = {
 352                 .type = CALLBACKTYPE_event,
 353                 .address = { .ip = (unsigned long)&xen_event_callback },
 354         };
 355
 356         xen_init_IRQ();
 357         BUG_ON(HYPERVISOR_callback_op(CALLBACKOP_register, &event));
 358         late_time_init = xen_bind_early_percpu_irq;
 359 }
 360
 361 void
 362 xen_platform_send_ipi(int cpu, int vector, int delivery_mode, int redirect)
 363 {
 364 #ifdef CONFIG_SMP
 365         /* TODO: we need to call vcpu_up here */
 366         if (unlikely(vector == ap_wakeup_vector)) {
 367                 /* XXX
 368                  * This should be in __cpu_up(cpu) in ia64 smpboot.c
 369                  * like x86. But don't want to modify it,
 370                  * keep it untouched.
 371                  */
 372                 xen_smp_intr_init_early(cpu);
 373
 374                 xen_send_ipi(cpu, vector);
 375                 /* vcpu_prepare_and_up(cpu); */
 376                 return;
 377         }
 378 #endif
 379
 380         switch (vector) {
 381         case IA64_IPI_VECTOR:
 382                 xen_send_IPI_one(cpu, XEN_IPI_VECTOR);
 383                 break;
 384         case IA64_IPI_RESCHEDULE:
 385                 xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
 386                 break;
 387         case IA64_CMCP_VECTOR:
 388                 xen_send_IPI_one(cpu, XEN_CMCP_VECTOR);
 389                 break;
 390         case IA64_CPEP_VECTOR:
 391                 xen_send_IPI_one(cpu, XEN_CPEP_VECTOR);
 392                 break;
 393         case IA64_TIMER_VECTOR: {
 394                 /* this is used only once by check_sal_cache_flush()
 395                    at boot time */
 396                 static int used = 0;
 397                 if (!used) {
 398                         xen_send_ipi(cpu, IA64_TIMER_VECTOR);
 399                         used = 1;
 400                         break;
 401                 }
 402                 /* fallthrough */
 403         }
 404         default:
 405                 printk(KERN_WARNING "Unsupported IPI type 0x%x\n",
 406                        vector);
 407                 notify_remote_via_irq(0); /* defaults to 0 irq */
 408                 break;
 409         }
 410 }
 411
 412 static void __init
 413 xen_register_ipi(void)
 414 {
 415 #ifdef CONFIG_SMP
 416         register_percpu_irq(IA64_IPI_VECTOR, &xen_ipi_irqaction);
 417         register_percpu_irq(IA64_IPI_RESCHEDULE, &xen_resched_irqaction);
 418         register_percpu_irq(IA64_IPI_LOCAL_TLB_FLUSH, &xen_tlb_irqaction);
 419 #endif
 420 }
 421
 422 static void
 423 xen_resend_irq(unsigned int vector)
 424 {
 425         (void)resend_irq_on_evtchn(vector);
 426 }
 427
 428 const struct pv_irq_ops xen_irq_ops __initdata = {
 429         .register_ipi = xen_register_ipi,
 430
 431         .assign_irq_vector = xen_assign_irq_vector,
 432         .free_irq_vector = xen_free_irq_vector,
 433         .register_percpu_irq = xen_register_percpu_irq,
 434
 435         .resend_irq = xen_resend_irq,
 436 };