arch/blackfin/mach-common/smp.c

   1 /*
   2  * IPI management based on arch/arm/kernel/smp.c (Copyright 2002 ARM Limited)
   3  *
   4  * Copyright 2007-2009 Analog Devices Inc.
   5  *                         Philippe Gerum <rpm@xenomai.org>
   6  *
   7  * Licensed under the GPL-2.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/delay.h>
  12 #include <linux/init.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/sched.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/cache.h>
  17 #include <linux/clockchips.h>
  18 #include <linux/profile.h>
  19 #include <linux/errno.h>
  20 #include <linux/mm.h>
  21 #include <linux/cpu.h>
  22 #include <linux/smp.h>
  23 #include <linux/cpumask.h>
  24 #include <linux/seq_file.h>
  25 #include <linux/irq.h>
  26 #include <linux/slab.h>
  27 #include <linux/atomic.h>
  28 #include <asm/cacheflush.h>
  29 #include <asm/irq_handler.h>
  30 #include <asm/mmu_context.h>
  31 #include <asm/pgtable.h>
  32 #include <asm/pgalloc.h>
  33 #include <asm/processor.h>
  34 #include <asm/ptrace.h>
  35 #include <asm/cpu.h>
  36 #include <asm/time.h>
  37 #include <linux/err.h>
  38
  39 /*
  40  * Anomaly notes:
  41  * 05000120 - we always define corelock as 32-bit integer in L2
  42  */
  43 struct corelock_slot corelock __attribute__ ((__section__(".l2.bss")));
  44
  45 #ifdef CONFIG_ICACHE_FLUSH_L1
  46 unsigned long blackfin_iflush_l1_entry[NR_CPUS];
  47 #endif
  48
  49 struct blackfin_initial_pda __cpuinitdata initial_pda_coreb;
  50
  51 #define BFIN_IPI_TIMER        0
  52 #define BFIN_IPI_RESCHEDULE   1
  53 #define BFIN_IPI_CALL_FUNC    2
  54 #define BFIN_IPI_CPU_STOP     3
  55
  56 struct blackfin_flush_data {
  57         unsigned long start;
  58         unsigned long end;
  59 };
  60
  61 void *secondary_stack;
  62
  63
  64 struct smp_call_struct {
  65         void (*func)(void *info);
  66         void *info;
  67         int wait;
  68         cpumask_t *waitmask;
  69 };
  70
  71 static struct blackfin_flush_data smp_flush_data;
  72
  73 static DEFINE_SPINLOCK(stop_lock);
  74
  75 struct ipi_message {
  76         unsigned long type;
  77         struct smp_call_struct call_struct;
  78 };
  79
  80 /* A magic number - stress test shows this is safe for common cases */
  81 #define BFIN_IPI_MSGQ_LEN 5
  82
  83 /* Simple FIFO buffer, overflow leads to panic */
  84 struct ipi_message_queue {
  85         spinlock_t lock;
  86         unsigned long count;
  87         unsigned long head; /* head of the queue */
  88         struct ipi_message ipi_message[BFIN_IPI_MSGQ_LEN];
  89 };
  90
  91 static DEFINE_PER_CPU(struct ipi_message_queue, ipi_msg_queue);
  92
  93 static void ipi_cpu_stop(unsigned int cpu)
  94 {
  95         spin_lock(&stop_lock);
  96         printk(KERN_CRIT "CPU%u: stopping\n", cpu);
  97         dump_stack();
  98         spin_unlock(&stop_lock);
  99
 100         set_cpu_online(cpu, false);
 101
 102         local_irq_disable();
 103
 104         while (1)
 105                 SSYNC();
 106 }
 107
 108 static void ipi_flush_icache(void *info)
 109 {
 110         struct blackfin_flush_data *fdata = info;
 111
 112         /* Invalidate the memory holding the bounds of the flushed region. */
 113         blackfin_dcache_invalidate_range((unsigned long)fdata,
 114                                          (unsigned long)fdata + sizeof(*fdata));
 115
 116         /* Make sure all write buffers in the data side of the core
 117          * are flushed before trying to invalidate the icache.  This
 118          * needs to be after the data flush and before the icache
 119          * flush so that the SSYNC does the right thing in preventing
 120          * the instruction prefetcher from hitting things in cached
 121          * memory at the wrong time -- it runs much further ahead than
 122          * the pipeline.
 123          */
 124         SSYNC();
 125
 126         /* ipi_flaush_icache is invoked by generic flush_icache_range,
 127          * so call blackfin arch icache flush directly here.
 128          */
 129         blackfin_icache_flush_range(fdata->start, fdata->end);
 130 }
 131
 132 static void ipi_call_function(unsigned int cpu, struct ipi_message *msg)
 133 {
 134         int wait;
 135         void (*func)(void *info);
 136         void *info;
 137         func = msg->call_struct.func;
 138         info = msg->call_struct.info;
 139         wait = msg->call_struct.wait;
 140         func(info);
 141         if (wait) {
 142 #ifdef __ARCH_SYNC_CORE_DCACHE
 143                 /*
 144                  * 'wait' usually means synchronization between CPUs.
 145                  * Invalidate D cache in case shared data was changed
 146                  * by func() to ensure cache coherence.
 147                  */
 148                 resync_core_dcache();
 149 #endif
 150                 cpumask_clear_cpu(cpu, msg->call_struct.waitmask);
 151         }
 152 }
 153
 154 /* Use IRQ_SUPPLE_0 to request reschedule.
 155  * When returning from interrupt to user space,
 156  * there is chance to reschedule */
 157 static irqreturn_t ipi_handler_int0(int irq, void *dev_instance)
 158 {
 159         unsigned int cpu = smp_processor_id();
 160
 161         platform_clear_ipi(cpu, IRQ_SUPPLE_0);
 162         return IRQ_HANDLED;
 163 }
 164
 165 DECLARE_PER_CPU(struct clock_event_device, coretmr_events);
 166 void ipi_timer(void)
 167 {
 168         int cpu = smp_processor_id();
 169         struct clock_event_device *evt = &per_cpu(coretmr_events, cpu);
 170         evt->event_handler(evt);
 171 }
 172
 173 static irqreturn_t ipi_handler_int1(int irq, void *dev_instance)
 174 {
 175         struct ipi_message *msg;
 176         struct ipi_message_queue *msg_queue;
 177         unsigned int cpu = smp_processor_id();
 178         unsigned long flags;
 179
 180         platform_clear_ipi(cpu, IRQ_SUPPLE_1);
 181
 182         msg_queue = &__get_cpu_var(ipi_msg_queue);
 183
 184         spin_lock_irqsave(&msg_queue->lock, flags);
 185
 186         while (msg_queue->count) {
 187                 msg = &msg_queue->ipi_message[msg_queue->head];
 188                 switch (msg->type) {
 189                 case BFIN_IPI_TIMER:
 190                         ipi_timer();
 191                         break;
 192                 case BFIN_IPI_RESCHEDULE:
 193                         scheduler_ipi();
 194                         break;
 195                 case BFIN_IPI_CALL_FUNC:
 196                         ipi_call_function(cpu, msg);
 197                         break;
 198                 case BFIN_IPI_CPU_STOP:
 199                         ipi_cpu_stop(cpu);
 200                         break;
 201                 default:
 202                         printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%lx\n",
 203                                cpu, msg->type);
 204                         break;
 205                 }
 206                 msg_queue->head++;
 207                 msg_queue->head %= BFIN_IPI_MSGQ_LEN;
 208                 msg_queue->count--;
 209         }
 210         spin_unlock_irqrestore(&msg_queue->lock, flags);
 211         return IRQ_HANDLED;
 212 }
 213
 214 static void ipi_queue_init(void)
 215 {
 216         unsigned int cpu;
 217         struct ipi_message_queue *msg_queue;
 218         for_each_possible_cpu(cpu) {
 219                 msg_queue = &per_cpu(ipi_msg_queue, cpu);
 220                 spin_lock_init(&msg_queue->lock);
 221                 msg_queue->count = 0;
 222                 msg_queue->head = 0;
 223         }
 224 }
 225
 226 static inline void smp_send_message(cpumask_t callmap, unsigned long type,
 227                                         void (*func) (void *info), void *info, int wait)
 228 {
 229         unsigned int cpu;
 230         struct ipi_message_queue *msg_queue;
 231         struct ipi_message *msg;
 232         unsigned long flags, next_msg;
 233         cpumask_t waitmask; /* waitmask is shared by all cpus */
 234
 235         cpumask_copy(&waitmask, &callmap);
 236         for_each_cpu(cpu, &callmap) {
 237                 msg_queue = &per_cpu(ipi_msg_queue, cpu);
 238                 spin_lock_irqsave(&msg_queue->lock, flags);
 239                 if (msg_queue->count < BFIN_IPI_MSGQ_LEN) {
 240                         next_msg = (msg_queue->head + msg_queue->count)
 241                                         % BFIN_IPI_MSGQ_LEN;
 242                         msg = &msg_queue->ipi_message[next_msg];
 243                         msg->type = type;
 244                         if (type == BFIN_IPI_CALL_FUNC) {
 245                                 msg->call_struct.func = func;
 246                                 msg->call_struct.info = info;
 247                                 msg->call_struct.wait = wait;
 248                                 msg->call_struct.waitmask = &waitmask;
 249                         }
 250                         msg_queue->count++;
 251                 } else
 252                         panic("IPI message queue overflow\n");
 253                 spin_unlock_irqrestore(&msg_queue->lock, flags);
 254                 platform_send_ipi_cpu(cpu, IRQ_SUPPLE_1);
 255         }
 256
 257         if (wait) {
 258                 while (!cpumask_empty(&waitmask))
 259                         blackfin_dcache_invalidate_range(
 260                                 (unsigned long)(&waitmask),
 261                                 (unsigned long)(&waitmask));
 262 #ifdef __ARCH_SYNC_CORE_DCACHE
 263                 /*
 264                  * Invalidate D cache in case shared data was changed by
 265                  * other processors to ensure cache coherence.
 266                  */
 267                 resync_core_dcache();
 268 #endif
 269         }
 270 }
 271
 272 int smp_call_function(void (*func)(void *info), void *info, int wait)
 273 {
 274         cpumask_t callmap;
 275
 276         preempt_disable();
 277         cpumask_copy(&callmap, cpu_online_mask);
 278         cpumask_clear_cpu(smp_processor_id(), &callmap);
 279         if (!cpumask_empty(&callmap))
 280                 smp_send_message(callmap, BFIN_IPI_CALL_FUNC, func, info, wait);
 281
 282         preempt_enable();
 283
 284         return 0;
 285 }
 286 EXPORT_SYMBOL_GPL(smp_call_function);
 287
 288 int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
 289                                 int wait)
 290 {
 291         unsigned int cpu = cpuid;
 292         cpumask_t callmap;
 293
 294         if (cpu_is_offline(cpu))
 295                 return 0;
 296         cpumask_clear(&callmap);
 297         cpumask_set_cpu(cpu, &callmap);
 298
 299         smp_send_message(callmap, BFIN_IPI_CALL_FUNC, func, info, wait);
 300
 301         return 0;
 302 }
 303 EXPORT_SYMBOL_GPL(smp_call_function_single);
 304
 305 void smp_send_reschedule(int cpu)
 306 {
 307         cpumask_t callmap;
 308         /* simply trigger an ipi */
 309
 310         cpumask_clear(&callmap);
 311         cpumask_set_cpu(cpu, &callmap);
 312
 313         smp_send_message(callmap, BFIN_IPI_RESCHEDULE, NULL, NULL, 0);
 314
 315         return;
 316 }
 317
 318 void smp_send_msg(const struct cpumask *mask, unsigned long type)
 319 {
 320         smp_send_message(*mask, type, NULL, NULL, 0);
 321 }
 322
 323 void smp_timer_broadcast(const struct cpumask *mask)
 324 {
 325         smp_send_msg(mask, BFIN_IPI_TIMER);
 326 }
 327
 328 void smp_send_stop(void)
 329 {
 330         cpumask_t callmap;
 331
 332         preempt_disable();
 333         cpumask_copy(&callmap, cpu_online_mask);
 334         cpumask_clear_cpu(smp_processor_id(), &callmap);
 335         if (!cpumask_empty(&callmap))
 336                 smp_send_message(callmap, BFIN_IPI_CPU_STOP, NULL, NULL, 0);
 337
 338         preempt_enable();
 339
 340         return;
 341 }
 342
 343 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 344 {
 345         int ret;
 346         struct blackfin_cpudata *ci = &per_cpu(cpu_data, cpu);
 347         struct task_struct *idle = ci->idle;
 348
 349         if (idle) {
 350                 free_task(idle);
 351                 idle = NULL;
 352         }
 353
 354         if (!idle) {
 355                 idle = fork_idle(cpu);
 356                 if (IS_ERR(idle)) {
 357                         printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
 358                         return PTR_ERR(idle);
 359                 }
 360                 ci->idle = idle;
 361         } else {
 362                 init_idle(idle, cpu);
 363         }
 364         secondary_stack = task_stack_page(idle) + THREAD_SIZE;
 365
 366         ret = platform_boot_secondary(cpu, idle);
 367
 368         secondary_stack = NULL;
 369
 370         return ret;
 371 }
 372
 373 static void __cpuinit setup_secondary(unsigned int cpu)
 374 {
 375         unsigned long ilat;
 376
 377         bfin_write_IMASK(0);
 378         CSYNC();
 379         ilat = bfin_read_ILAT();
 380         CSYNC();
 381         bfin_write_ILAT(ilat);
 382         CSYNC();
 383
 384         /* Enable interrupt levels IVG7-15. IARs have been already
 385          * programmed by the boot CPU.  */
 386         bfin_irq_flags |= IMASK_IVG15 |
 387             IMASK_IVG14 | IMASK_IVG13 | IMASK_IVG12 | IMASK_IVG11 |
 388             IMASK_IVG10 | IMASK_IVG9 | IMASK_IVG8 | IMASK_IVG7 | IMASK_IVGHW;
 389 }
 390
 391 void __cpuinit secondary_start_kernel(void)
 392 {
 393         unsigned int cpu = smp_processor_id();
 394         struct mm_struct *mm = &init_mm;
 395
 396         if (_bfin_swrst & SWRST_DBL_FAULT_B) {
 397                 printk(KERN_EMERG "CoreB Recovering from DOUBLE FAULT event\n");
 398 #ifdef CONFIG_DEBUG_DOUBLEFAULT
 399                 printk(KERN_EMERG " While handling exception (EXCAUSE = %#x) at %pF\n",
 400                         initial_pda_coreb.seqstat_doublefault & SEQSTAT_EXCAUSE,
 401                         initial_pda_coreb.retx_doublefault);
 402                 printk(KERN_NOTICE "   DCPLB_FAULT_ADDR: %pF\n",
 403                         initial_pda_coreb.dcplb_doublefault_addr);
 404                 printk(KERN_NOTICE "   ICPLB_FAULT_ADDR: %pF\n",
 405                         initial_pda_coreb.icplb_doublefault_addr);
 406 #endif
 407                 printk(KERN_NOTICE " The instruction at %pF caused a double exception\n",
 408                         initial_pda_coreb.retx);
 409         }
 410
 411         /*
 412          * We want the D-cache to be enabled early, in case the atomic
 413          * support code emulates cache coherence (see
 414          * __ARCH_SYNC_CORE_DCACHE).
 415          */
 416         init_exception_vectors();
 417
 418         local_irq_disable();
 419
 420         /* Attach the new idle task to the global mm. */
 421         atomic_inc(&mm->mm_users);
 422         atomic_inc(&mm->mm_count);
 423         current->active_mm = mm;
 424
 425         preempt_disable();
 426
 427         setup_secondary(cpu);
 428
 429         platform_secondary_init(cpu);
 430
 431         /* setup local core timer */
 432         bfin_local_timer_setup();
 433
 434         local_irq_enable();
 435
 436         bfin_setup_caches(cpu);
 437
 438         notify_cpu_starting(cpu);
 439         /*
 440          * Calibrate loops per jiffy value.
 441          * IRQs need to be enabled here - D-cache can be invalidated
 442          * in timer irq handler, so core B can read correct jiffies.
 443          */
 444         calibrate_delay();
 445
 446         cpu_idle();
 447 }
 448
 449 void __init smp_prepare_boot_cpu(void)
 450 {
 451 }
 452
 453 void __init smp_prepare_cpus(unsigned int max_cpus)
 454 {
 455         platform_prepare_cpus(max_cpus);
 456         ipi_queue_init();
 457         platform_request_ipi(IRQ_SUPPLE_0, ipi_handler_int0);
 458         platform_request_ipi(IRQ_SUPPLE_1, ipi_handler_int1);
 459 }
 460
 461 void __init smp_cpus_done(unsigned int max_cpus)
 462 {
 463         unsigned long bogosum = 0;
 464         unsigned int cpu;
 465
 466         for_each_online_cpu(cpu)
 467                 bogosum += loops_per_jiffy;
 468
 469         printk(KERN_INFO "SMP: Total of %d processors activated "
 470                "(%lu.%02lu BogoMIPS).\n",
 471                num_online_cpus(),
 472                bogosum / (500000/HZ),
 473                (bogosum / (5000/HZ)) % 100);
 474 }
 475
 476 void smp_icache_flush_range_others(unsigned long start, unsigned long end)
 477 {
 478         smp_flush_data.start = start;
 479         smp_flush_data.end = end;
 480
 481         preempt_disable();
 482         if (smp_call_function(&ipi_flush_icache, &smp_flush_data, 1))
 483                 printk(KERN_WARNING "SMP: failed to run I-cache flush request on other CPUs\n");
 484         preempt_enable();
 485 }
 486 EXPORT_SYMBOL_GPL(smp_icache_flush_range_others);
 487
 488 #ifdef __ARCH_SYNC_CORE_ICACHE
 489 unsigned long icache_invld_count[NR_CPUS];
 490 void resync_core_icache(void)
 491 {
 492         unsigned int cpu = get_cpu();
 493         blackfin_invalidate_entire_icache();
 494         icache_invld_count[cpu]++;
 495         put_cpu();
 496 }
 497 EXPORT_SYMBOL(resync_core_icache);
 498 #endif
 499
 500 #ifdef __ARCH_SYNC_CORE_DCACHE
 501 unsigned long dcache_invld_count[NR_CPUS];
 502 unsigned long barrier_mask __attribute__ ((__section__(".l2.bss")));
 503
 504 void resync_core_dcache(void)
 505 {
 506         unsigned int cpu = get_cpu();
 507         blackfin_invalidate_entire_dcache();
 508         dcache_invld_count[cpu]++;
 509         put_cpu();
 510 }
 511 EXPORT_SYMBOL(resync_core_dcache);
 512 #endif
 513
 514 #ifdef CONFIG_HOTPLUG_CPU
 515 int __cpuexit __cpu_disable(void)
 516 {
 517         unsigned int cpu = smp_processor_id();
 518
 519         if (cpu == 0)
 520                 return -EPERM;
 521
 522         set_cpu_online(cpu, false);
 523         return 0;
 524 }
 525
 526 static DECLARE_COMPLETION(cpu_killed);
 527
 528 int __cpuexit __cpu_die(unsigned int cpu)
 529 {
 530         return wait_for_completion_timeout(&cpu_killed, 5000);
 531 }
 532
 533 void cpu_die(void)
 534 {
 535         complete(&cpu_killed);
 536
 537         atomic_dec(&init_mm.mm_users);
 538         atomic_dec(&init_mm.mm_count);
 539
 540         local_irq_disable();
 541         platform_cpu_die();
 542 }
 543 #endif