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 initial_pda_coreb;
  50
  51 enum ipi_message_type {
  52         BFIN_IPI_NONE,
  53         BFIN_IPI_TIMER,
  54         BFIN_IPI_RESCHEDULE,
  55         BFIN_IPI_CALL_FUNC,
  56         BFIN_IPI_CALL_FUNC_SINGLE,
  57         BFIN_IPI_CPU_STOP,
  58 };
  59
  60 struct blackfin_flush_data {
  61         unsigned long start;
  62         unsigned long end;
  63 };
  64
  65 void *secondary_stack;
  66
  67 static struct blackfin_flush_data smp_flush_data;
  68
  69 static DEFINE_SPINLOCK(stop_lock);
  70
  71 /* A magic number - stress test shows this is safe for common cases */
  72 #define BFIN_IPI_MSGQ_LEN 5
  73
  74 /* Simple FIFO buffer, overflow leads to panic */
  75 struct ipi_data {
  76         atomic_t count;
  77         atomic_t bits;
  78 };
  79
  80 static DEFINE_PER_CPU(struct ipi_data, bfin_ipi);
  81
  82 static void ipi_cpu_stop(unsigned int cpu)
  83 {
  84         spin_lock(&stop_lock);
  85         printk(KERN_CRIT "CPU%u: stopping\n", cpu);
  86         dump_stack();
  87         spin_unlock(&stop_lock);
  88
  89         set_cpu_online(cpu, false);
  90
  91         local_irq_disable();
  92
  93         while (1)
  94                 SSYNC();
  95 }
  96
  97 static void ipi_flush_icache(void *info)
  98 {
  99         struct blackfin_flush_data *fdata = info;
 100
 101         /* Invalidate the memory holding the bounds of the flushed region. */
 102         blackfin_dcache_invalidate_range((unsigned long)fdata,
 103                                          (unsigned long)fdata + sizeof(*fdata));
 104
 105         /* Make sure all write buffers in the data side of the core
 106          * are flushed before trying to invalidate the icache.  This
 107          * needs to be after the data flush and before the icache
 108          * flush so that the SSYNC does the right thing in preventing
 109          * the instruction prefetcher from hitting things in cached
 110          * memory at the wrong time -- it runs much further ahead than
 111          * the pipeline.
 112          */
 113         SSYNC();
 114
 115         /* ipi_flaush_icache is invoked by generic flush_icache_range,
 116          * so call blackfin arch icache flush directly here.
 117          */
 118         blackfin_icache_flush_range(fdata->start, fdata->end);
 119 }
 120
 121 /* Use IRQ_SUPPLE_0 to request reschedule.
 122  * When returning from interrupt to user space,
 123  * there is chance to reschedule */
 124 static irqreturn_t ipi_handler_int0(int irq, void *dev_instance)
 125 {
 126         unsigned int cpu = smp_processor_id();
 127
 128         platform_clear_ipi(cpu, IRQ_SUPPLE_0);
 129         return IRQ_HANDLED;
 130 }
 131
 132 DECLARE_PER_CPU(struct clock_event_device, coretmr_events);
 133 void ipi_timer(void)
 134 {
 135         int cpu = smp_processor_id();
 136         struct clock_event_device *evt = &per_cpu(coretmr_events, cpu);
 137         evt->event_handler(evt);
 138 }
 139
 140 static irqreturn_t ipi_handler_int1(int irq, void *dev_instance)
 141 {
 142         struct ipi_data *bfin_ipi_data;
 143         unsigned int cpu = smp_processor_id();
 144         unsigned long pending;
 145         unsigned long msg;
 146
 147         platform_clear_ipi(cpu, IRQ_SUPPLE_1);
 148
 149         smp_rmb();
 150         bfin_ipi_data = &__get_cpu_var(bfin_ipi);
 151         while ((pending = atomic_xchg(&bfin_ipi_data->bits, 0)) != 0) {
 152                 msg = 0;
 153                 do {
 154                         msg = find_next_bit(&pending, BITS_PER_LONG, msg + 1);
 155                         switch (msg) {
 156                         case BFIN_IPI_TIMER:
 157                                 ipi_timer();
 158                                 break;
 159                         case BFIN_IPI_RESCHEDULE:
 160                                 scheduler_ipi();
 161                                 break;
 162                         case BFIN_IPI_CALL_FUNC:
 163                                 generic_smp_call_function_interrupt();
 164                                 break;
 165                         case BFIN_IPI_CALL_FUNC_SINGLE:
 166                                 generic_smp_call_function_single_interrupt();
 167                                 break;
 168                         case BFIN_IPI_CPU_STOP:
 169                                 ipi_cpu_stop(cpu);
 170                                 break;
 171                         default:
 172                                 goto out;
 173                         }
 174                         atomic_dec(&bfin_ipi_data->count);
 175                 } while (msg < BITS_PER_LONG);
 176
 177         }
 178 out:
 179         return IRQ_HANDLED;
 180 }
 181
 182 static void bfin_ipi_init(void)
 183 {
 184         unsigned int cpu;
 185         struct ipi_data *bfin_ipi_data;
 186         for_each_possible_cpu(cpu) {
 187                 bfin_ipi_data = &per_cpu(bfin_ipi, cpu);
 188                 atomic_set(&bfin_ipi_data->bits, 0);
 189                 atomic_set(&bfin_ipi_data->count, 0);
 190         }
 191 }
 192
 193 void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg)
 194 {
 195         unsigned int cpu;
 196         struct ipi_data *bfin_ipi_data;
 197         unsigned long flags;
 198
 199         local_irq_save(flags);
 200         for_each_cpu(cpu, cpumask) {
 201                 bfin_ipi_data = &per_cpu(bfin_ipi, cpu);
 202                 atomic_set_mask((1 << msg), &bfin_ipi_data->bits);
 203                 atomic_inc(&bfin_ipi_data->count);
 204         }
 205         local_irq_restore(flags);
 206         smp_wmb();
 207         for_each_cpu(cpu, cpumask)
 208                 platform_send_ipi_cpu(cpu, IRQ_SUPPLE_1);
 209 }
 210
 211 void arch_send_call_function_single_ipi(int cpu)
 212 {
 213         send_ipi(cpumask_of(cpu), BFIN_IPI_CALL_FUNC_SINGLE);
 214 }
 215
 216 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 217 {
 218         send_ipi(mask, BFIN_IPI_CALL_FUNC);
 219 }
 220
 221 void smp_send_reschedule(int cpu)
 222 {
 223         send_ipi(cpumask_of(cpu), BFIN_IPI_RESCHEDULE);
 224
 225         return;
 226 }
 227
 228 void smp_send_msg(const struct cpumask *mask, unsigned long type)
 229 {
 230         send_ipi(mask, type);
 231 }
 232
 233 void smp_timer_broadcast(const struct cpumask *mask)
 234 {
 235         smp_send_msg(mask, BFIN_IPI_TIMER);
 236 }
 237
 238 void smp_send_stop(void)
 239 {
 240         cpumask_t callmap;
 241
 242         preempt_disable();
 243         cpumask_copy(&callmap, cpu_online_mask);
 244         cpumask_clear_cpu(smp_processor_id(), &callmap);
 245         if (!cpumask_empty(&callmap))
 246                 send_ipi(&callmap, BFIN_IPI_CPU_STOP);
 247
 248         preempt_enable();
 249
 250         return;
 251 }
 252
 253 int __cpu_up(unsigned int cpu, struct task_struct *idle)
 254 {
 255         int ret;
 256
 257         secondary_stack = task_stack_page(idle) + THREAD_SIZE;
 258
 259         ret = platform_boot_secondary(cpu, idle);
 260
 261         secondary_stack = NULL;
 262
 263         return ret;
 264 }
 265
 266 static void setup_secondary(unsigned int cpu)
 267 {
 268         unsigned long ilat;
 269
 270         bfin_write_IMASK(0);
 271         CSYNC();
 272         ilat = bfin_read_ILAT();
 273         CSYNC();
 274         bfin_write_ILAT(ilat);
 275         CSYNC();
 276
 277         /* Enable interrupt levels IVG7-15. IARs have been already
 278          * programmed by the boot CPU.  */
 279         bfin_irq_flags |= IMASK_IVG15 |
 280             IMASK_IVG14 | IMASK_IVG13 | IMASK_IVG12 | IMASK_IVG11 |
 281             IMASK_IVG10 | IMASK_IVG9 | IMASK_IVG8 | IMASK_IVG7 | IMASK_IVGHW;
 282 }
 283
 284 void secondary_start_kernel(void)
 285 {
 286         unsigned int cpu = smp_processor_id();
 287         struct mm_struct *mm = &init_mm;
 288
 289         if (_bfin_swrst & SWRST_DBL_FAULT_B) {
 290                 printk(KERN_EMERG "CoreB Recovering from DOUBLE FAULT event\n");
 291 #ifdef CONFIG_DEBUG_DOUBLEFAULT
 292                 printk(KERN_EMERG " While handling exception (EXCAUSE = %#x) at %pF\n",
 293                         initial_pda_coreb.seqstat_doublefault & SEQSTAT_EXCAUSE,
 294                         initial_pda_coreb.retx_doublefault);
 295                 printk(KERN_NOTICE "   DCPLB_FAULT_ADDR: %pF\n",
 296                         initial_pda_coreb.dcplb_doublefault_addr);
 297                 printk(KERN_NOTICE "   ICPLB_FAULT_ADDR: %pF\n",
 298                         initial_pda_coreb.icplb_doublefault_addr);
 299 #endif
 300                 printk(KERN_NOTICE " The instruction at %pF caused a double exception\n",
 301                         initial_pda_coreb.retx);
 302         }
 303
 304         /*
 305          * We want the D-cache to be enabled early, in case the atomic
 306          * support code emulates cache coherence (see
 307          * __ARCH_SYNC_CORE_DCACHE).
 308          */
 309         init_exception_vectors();
 310
 311         local_irq_disable();
 312
 313         /* Attach the new idle task to the global mm. */
 314         atomic_inc(&mm->mm_users);
 315         atomic_inc(&mm->mm_count);
 316         current->active_mm = mm;
 317
 318         preempt_disable();
 319
 320         setup_secondary(cpu);
 321
 322         platform_secondary_init(cpu);
 323         /* setup local core timer */
 324         bfin_local_timer_setup();
 325
 326         local_irq_enable();
 327
 328         bfin_setup_caches(cpu);
 329
 330         notify_cpu_starting(cpu);
 331         /*
 332          * Calibrate loops per jiffy value.
 333          * IRQs need to be enabled here - D-cache can be invalidated
 334          * in timer irq handler, so core B can read correct jiffies.
 335          */
 336         calibrate_delay();
 337
 338         /* We are done with local CPU inits, unblock the boot CPU. */
 339         set_cpu_online(cpu, true);
 340         cpu_startup_entry(CPUHP_ONLINE);
 341 }
 342
 343 void __init smp_prepare_boot_cpu(void)
 344 {
 345 }
 346
 347 void __init smp_prepare_cpus(unsigned int max_cpus)
 348 {
 349         platform_prepare_cpus(max_cpus);
 350         bfin_ipi_init();
 351         platform_request_ipi(IRQ_SUPPLE_0, ipi_handler_int0);
 352         platform_request_ipi(IRQ_SUPPLE_1, ipi_handler_int1);
 353 }
 354
 355 void __init smp_cpus_done(unsigned int max_cpus)
 356 {
 357         unsigned long bogosum = 0;
 358         unsigned int cpu;
 359
 360         for_each_online_cpu(cpu)
 361                 bogosum += loops_per_jiffy;
 362
 363         printk(KERN_INFO "SMP: Total of %d processors activated "
 364                "(%lu.%02lu BogoMIPS).\n",
 365                num_online_cpus(),
 366                bogosum / (500000/HZ),
 367                (bogosum / (5000/HZ)) % 100);
 368 }
 369
 370 void smp_icache_flush_range_others(unsigned long start, unsigned long end)
 371 {
 372         smp_flush_data.start = start;
 373         smp_flush_data.end = end;
 374
 375         preempt_disable();
 376         if (smp_call_function(&ipi_flush_icache, &smp_flush_data, 1))
 377                 printk(KERN_WARNING "SMP: failed to run I-cache flush request on other CPUs\n");
 378         preempt_enable();
 379 }
 380 EXPORT_SYMBOL_GPL(smp_icache_flush_range_others);
 381
 382 #ifdef __ARCH_SYNC_CORE_ICACHE
 383 unsigned long icache_invld_count[NR_CPUS];
 384 void resync_core_icache(void)
 385 {
 386         unsigned int cpu = get_cpu();
 387         blackfin_invalidate_entire_icache();
 388         icache_invld_count[cpu]++;
 389         put_cpu();
 390 }
 391 EXPORT_SYMBOL(resync_core_icache);
 392 #endif
 393
 394 #ifdef __ARCH_SYNC_CORE_DCACHE
 395 unsigned long dcache_invld_count[NR_CPUS];
 396 unsigned long barrier_mask __attribute__ ((__section__(".l2.bss")));
 397
 398 void resync_core_dcache(void)
 399 {
 400         unsigned int cpu = get_cpu();
 401         blackfin_invalidate_entire_dcache();
 402         dcache_invld_count[cpu]++;
 403         put_cpu();
 404 }
 405 EXPORT_SYMBOL(resync_core_dcache);
 406 #endif
 407
 408 #ifdef CONFIG_HOTPLUG_CPU
 409 int __cpu_disable(void)
 410 {
 411         unsigned int cpu = smp_processor_id();
 412
 413         if (cpu == 0)
 414                 return -EPERM;
 415
 416         set_cpu_online(cpu, false);
 417         return 0;
 418 }
 419
 420 static DECLARE_COMPLETION(cpu_killed);
 421
 422 int __cpu_die(unsigned int cpu)
 423 {
 424         return wait_for_completion_timeout(&cpu_killed, 5000);
 425 }
 426
 427 void cpu_die(void)
 428 {
 429         complete(&cpu_killed);
 430
 431         atomic_dec(&init_mm.mm_users);
 432         atomic_dec(&init_mm.mm_count);
 433
 434         local_irq_disable();
 435         platform_cpu_die();
 436 }
 437 #endif