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