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 enum ipi_message_type {
  52         BFIN_IPI_TIMER,
  53         BFIN_IPI_RESCHEDULE,
  54         BFIN_IPI_CALL_FUNC,
  55         BFIN_IPI_CALL_FUNC_SINGLE,
  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         unsigned long count;
  76         unsigned long 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         bfin_ipi_data = &__get_cpu_var(bfin_ipi);
 149
 150         while ((pending = 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
 165                         case BFIN_IPI_CALL_FUNC_SINGLE:
 166                                 generic_smp_call_function_single_interrupt();
 167                                 break;
 168
 169                         case BFIN_IPI_CPU_STOP:
 170                                 ipi_cpu_stop(cpu);
 171                                 break;
 172                         }
 173                 } while (msg < BITS_PER_LONG);
 174
 175                 smp_mb();
 176         }
 177         return IRQ_HANDLED;
 178 }
 179
 180 static void bfin_ipi_init(void)
 181 {
 182         unsigned int cpu;
 183         struct ipi_data *bfin_ipi_data;
 184         for_each_possible_cpu(cpu) {
 185                 bfin_ipi_data = &per_cpu(bfin_ipi, cpu);
 186                 bfin_ipi_data->bits = 0;
 187                 bfin_ipi_data->count = 0;
 188         }
 189 }
 190
 191 void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg)
 192 {
 193         unsigned int cpu;
 194         struct ipi_data *bfin_ipi_data;
 195         unsigned long flags;
 196
 197         local_irq_save(flags);
 198
 199         for_each_cpu(cpu, cpumask) {
 200                 bfin_ipi_data = &per_cpu(bfin_ipi, cpu);
 201                 smp_mb();
 202                 set_bit(msg, &bfin_ipi_data->bits);
 203                 bfin_ipi_data->count++;
 204                 platform_send_ipi_cpu(cpu, IRQ_SUPPLE_1);
 205         }
 206
 207         local_irq_restore(flags);
 208 }
 209
 210 void arch_send_call_function_single_ipi(int cpu)
 211 {
 212         send_ipi(cpumask_of(cpu), BFIN_IPI_CALL_FUNC_SINGLE);
 213 }
 214
 215 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 216 {
 217         send_ipi(mask, BFIN_IPI_CALL_FUNC);
 218 }
 219
 220 void smp_send_reschedule(int cpu)
 221 {
 222         send_ipi(cpumask_of(cpu), BFIN_IPI_RESCHEDULE);
 223
 224         return;
 225 }
 226
 227 void smp_send_msg(const struct cpumask *mask, unsigned long type)
 228 {
 229         send_ipi(mask, type);
 230 }
 231
 232 void smp_timer_broadcast(const struct cpumask *mask)
 233 {
 234         smp_send_msg(mask, BFIN_IPI_TIMER);
 235 }
 236
 237 void smp_send_stop(void)
 238 {
 239         cpumask_t callmap;
 240
 241         preempt_disable();
 242         cpumask_copy(&callmap, cpu_online_mask);
 243         cpumask_clear_cpu(smp_processor_id(), &callmap);
 244         if (!cpumask_empty(&callmap))
 245                 send_ipi(&callmap, BFIN_IPI_CPU_STOP);
 246
 247         preempt_enable();
 248
 249         return;
 250 }
 251
 252 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
 253 {
 254         int ret;
 255
 256         secondary_stack = task_stack_page(idle) + THREAD_SIZE;
 257
 258         ret = platform_boot_secondary(cpu, idle);
 259
 260         secondary_stack = NULL;
 261
 262         return ret;
 263 }
 264
 265 static void __cpuinit setup_secondary(unsigned int cpu)
 266 {
 267         unsigned long ilat;
 268
 269         bfin_write_IMASK(0);
 270         CSYNC();
 271         ilat = bfin_read_ILAT();
 272         CSYNC();
 273         bfin_write_ILAT(ilat);
 274         CSYNC();
 275
 276         /* Enable interrupt levels IVG7-15. IARs have been already
 277          * programmed by the boot CPU.  */
 278         bfin_irq_flags |= IMASK_IVG15 |
 279             IMASK_IVG14 | IMASK_IVG13 | IMASK_IVG12 | IMASK_IVG11 |
 280             IMASK_IVG10 | IMASK_IVG9 | IMASK_IVG8 | IMASK_IVG7 | IMASK_IVGHW;
 281 }
 282
 283 void __cpuinit secondary_start_kernel(void)
 284 {
 285         unsigned int cpu = smp_processor_id();
 286         struct mm_struct *mm = &init_mm;
 287
 288         if (_bfin_swrst & SWRST_DBL_FAULT_B) {
 289                 printk(KERN_EMERG "CoreB Recovering from DOUBLE FAULT event\n");
 290 #ifdef CONFIG_DEBUG_DOUBLEFAULT
 291                 printk(KERN_EMERG " While handling exception (EXCAUSE = %#x) at %pF\n",
 292                         initial_pda_coreb.seqstat_doublefault & SEQSTAT_EXCAUSE,
 293                         initial_pda_coreb.retx_doublefault);
 294                 printk(KERN_NOTICE "   DCPLB_FAULT_ADDR: %pF\n",
 295                         initial_pda_coreb.dcplb_doublefault_addr);
 296                 printk(KERN_NOTICE "   ICPLB_FAULT_ADDR: %pF\n",
 297                         initial_pda_coreb.icplb_doublefault_addr);
 298 #endif
 299                 printk(KERN_NOTICE " The instruction at %pF caused a double exception\n",
 300                         initial_pda_coreb.retx);
 301         }
 302
 303         /*
 304          * We want the D-cache to be enabled early, in case the atomic
 305          * support code emulates cache coherence (see
 306          * __ARCH_SYNC_CORE_DCACHE).
 307          */
 308         init_exception_vectors();
 309
 310         local_irq_disable();
 311
 312         /* Attach the new idle task to the global mm. */
 313         atomic_inc(&mm->mm_users);
 314         atomic_inc(&mm->mm_count);
 315         current->active_mm = mm;
 316
 317         preempt_disable();
 318
 319         setup_secondary(cpu);
 320
 321         platform_secondary_init(cpu);
 322
 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         cpu_idle();
 339 }
 340
 341 void __init smp_prepare_boot_cpu(void)
 342 {
 343 }
 344
 345 void __init smp_prepare_cpus(unsigned int max_cpus)
 346 {
 347         platform_prepare_cpus(max_cpus);
 348         bfin_ipi_init();
 349         platform_request_ipi(IRQ_SUPPLE_0, ipi_handler_int0);
 350         platform_request_ipi(IRQ_SUPPLE_1, ipi_handler_int1);
 351 }
 352
 353 void __init smp_cpus_done(unsigned int max_cpus)
 354 {
 355         unsigned long bogosum = 0;
 356         unsigned int cpu;
 357
 358         for_each_online_cpu(cpu)
 359                 bogosum += loops_per_jiffy;
 360
 361         printk(KERN_INFO "SMP: Total of %d processors activated "
 362                "(%lu.%02lu BogoMIPS).\n",
 363                num_online_cpus(),
 364                bogosum / (500000/HZ),
 365                (bogosum / (5000/HZ)) % 100);
 366 }
 367
 368 void smp_icache_flush_range_others(unsigned long start, unsigned long end)
 369 {
 370         smp_flush_data.start = start;
 371         smp_flush_data.end = end;
 372
 373         preempt_disable();
 374         if (smp_call_function(&ipi_flush_icache, &smp_flush_data, 1))
 375                 printk(KERN_WARNING "SMP: failed to run I-cache flush request on other CPUs\n");
 376         preempt_enable();
 377 }
 378 EXPORT_SYMBOL_GPL(smp_icache_flush_range_others);
 379
 380 #ifdef __ARCH_SYNC_CORE_ICACHE
 381 unsigned long icache_invld_count[NR_CPUS];
 382 void resync_core_icache(void)
 383 {
 384         unsigned int cpu = get_cpu();
 385         blackfin_invalidate_entire_icache();
 386         icache_invld_count[cpu]++;
 387         put_cpu();
 388 }
 389 EXPORT_SYMBOL(resync_core_icache);
 390 #endif
 391
 392 #ifdef __ARCH_SYNC_CORE_DCACHE
 393 unsigned long dcache_invld_count[NR_CPUS];
 394 unsigned long barrier_mask __attribute__ ((__section__(".l2.bss")));
 395
 396 void resync_core_dcache(void)
 397 {
 398         unsigned int cpu = get_cpu();
 399         blackfin_invalidate_entire_dcache();
 400         dcache_invld_count[cpu]++;
 401         put_cpu();
 402 }
 403 EXPORT_SYMBOL(resync_core_dcache);
 404 #endif
 405
 406 #ifdef CONFIG_HOTPLUG_CPU
 407 int __cpuexit __cpu_disable(void)
 408 {
 409         unsigned int cpu = smp_processor_id();
 410
 411         if (cpu == 0)
 412                 return -EPERM;
 413
 414         set_cpu_online(cpu, false);
 415         return 0;
 416 }
 417
 418 static DECLARE_COMPLETION(cpu_killed);
 419
 420 int __cpuexit __cpu_die(unsigned int cpu)
 421 {
 422         return wait_for_completion_timeout(&cpu_killed, 5000);
 423 }
 424
 425 void cpu_die(void)
 426 {
 427         complete(&cpu_killed);
 428
 429         atomic_dec(&init_mm.mm_users);
 430         atomic_dec(&init_mm.mm_count);
 431
 432         local_irq_disable();
 433         platform_cpu_die();
 434 }
 435 #endif