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