arch/powerpc/platforms/85xx/smp.c

   1 /*
   2  * Author: Andy Fleming <afleming@freescale.com>
   3  *         Kumar Gala <galak@kernel.crashing.org>
   4  *
   5  * Copyright 2006-2008, 2011-2012, 2015 Freescale Semiconductor Inc.
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  */
  12
  13 #include <linux/stddef.h>
  14 #include <linux/kernel.h>
  15 #include <linux/sched/hotplug.h>
  16 #include <linux/init.h>
  17 #include <linux/delay.h>
  18 #include <linux/of.h>
  19 #include <linux/kexec.h>
  20 #include <linux/highmem.h>
  21 #include <linux/cpu.h>
  22 #include <linux/fsl/guts.h>
  23
  24 #include <asm/machdep.h>
  25 #include <asm/pgtable.h>
  26 #include <asm/page.h>
  27 #include <asm/mpic.h>
  28 #include <asm/cacheflush.h>
  29 #include <asm/dbell.h>
  30 #include <asm/code-patching.h>
  31 #include <asm/cputhreads.h>
  32 #include <asm/fsl_pm.h>
  33
  34 #include <sysdev/fsl_soc.h>
  35 #include <sysdev/mpic.h>
  36 #include "smp.h"
  37
  38 struct epapr_spin_table {
  39         u32     addr_h;
  40         u32     addr_l;
  41         u32     r3_h;
  42         u32     r3_l;
  43         u32     reserved;
  44         u32     pir;
  45 };
  46
  47 #ifdef CONFIG_HOTPLUG_CPU
  48 static u64 timebase;
  49 static int tb_req;
  50 static int tb_valid;
  51
  52 static void mpc85xx_give_timebase(void)
  53 {
  54         unsigned long flags;
  55
  56         local_irq_save(flags);
  57         hard_irq_disable();
  58
  59         while (!tb_req)
  60                 barrier();
  61         tb_req = 0;
  62
  63         qoriq_pm_ops->freeze_time_base(true);
  64 #ifdef CONFIG_PPC64
  65         /*
  66          * e5500/e6500 have a workaround for erratum A-006958 in place
  67          * that will reread the timebase until TBL is non-zero.
  68          * That would be a bad thing when the timebase is frozen.
  69          *
  70          * Thus, we read it manually, and instead of checking that
  71          * TBL is non-zero, we ensure that TB does not change.  We don't
  72          * do that for the main mftb implementation, because it requires
  73          * a scratch register
  74          */
  75         {
  76                 u64 prev;
  77
  78                 asm volatile("mfspr %0, %1" : "=r" (timebase) :
  79                              "i" (SPRN_TBRL));
  80
  81                 do {
  82                         prev = timebase;
  83                         asm volatile("mfspr %0, %1" : "=r" (timebase) :
  84                                      "i" (SPRN_TBRL));
  85                 } while (prev != timebase);
  86         }
  87 #else
  88         timebase = get_tb();
  89 #endif
  90         mb();
  91         tb_valid = 1;
  92
  93         while (tb_valid)
  94                 barrier();
  95
  96         qoriq_pm_ops->freeze_time_base(false);
  97
  98         local_irq_restore(flags);
  99 }
 100
 101 static void mpc85xx_take_timebase(void)
 102 {
 103         unsigned long flags;
 104
 105         local_irq_save(flags);
 106         hard_irq_disable();
 107
 108         tb_req = 1;
 109         while (!tb_valid)
 110                 barrier();
 111
 112         set_tb(timebase >> 32, timebase & 0xffffffff);
 113         isync();
 114         tb_valid = 0;
 115
 116         local_irq_restore(flags);
 117 }
 118
 119 static void smp_85xx_mach_cpu_die(void)
 120 {
 121         unsigned int cpu = smp_processor_id();
 122
 123         local_irq_disable();
 124         hard_irq_disable();
 125         /* mask all irqs to prevent cpu wakeup */
 126         qoriq_pm_ops->irq_mask(cpu);
 127
 128         idle_task_exit();
 129
 130         mtspr(SPRN_TCR, 0);
 131         mtspr(SPRN_TSR, mfspr(SPRN_TSR));
 132
 133         generic_set_cpu_dead(cpu);
 134
 135         cur_cpu_spec->cpu_down_flush();
 136
 137         qoriq_pm_ops->cpu_die(cpu);
 138
 139         while (1)
 140                 ;
 141 }
 142
 143 static void qoriq_cpu_kill(unsigned int cpu)
 144 {
 145         int i;
 146
 147         for (i = 0; i < 500; i++) {
 148                 if (is_cpu_dead(cpu)) {
 149 #ifdef CONFIG_PPC64
 150                         paca[cpu].cpu_start = 0;
 151 #endif
 152                         return;
 153                 }
 154                 msleep(20);
 155         }
 156         pr_err("CPU%d didn't die...\n", cpu);
 157 }
 158 #endif
 159
 160 /*
 161  * To keep it compatible with old boot program which uses
 162  * cache-inhibit spin table, we need to flush the cache
 163  * before accessing spin table to invalidate any staled data.
 164  * We also need to flush the cache after writing to spin
 165  * table to push data out.
 166  */
 167 static inline void flush_spin_table(void *spin_table)
 168 {
 169         flush_dcache_range((ulong)spin_table,
 170                 (ulong)spin_table + sizeof(struct epapr_spin_table));
 171 }
 172
 173 static inline u32 read_spin_table_addr_l(void *spin_table)
 174 {
 175         flush_dcache_range((ulong)spin_table,
 176                 (ulong)spin_table + sizeof(struct epapr_spin_table));
 177         return in_be32(&((struct epapr_spin_table *)spin_table)->addr_l);
 178 }
 179
 180 #ifdef CONFIG_PPC64
 181 static void wake_hw_thread(void *info)
 182 {
 183         void fsl_secondary_thread_init(void);
 184         unsigned long inia;
 185         int cpu = *(const int *)info;
 186
 187         inia = *(unsigned long *)fsl_secondary_thread_init;
 188         book3e_start_thread(cpu_thread_in_core(cpu), inia);
 189 }
 190 #endif
 191
 192 static int smp_85xx_start_cpu(int cpu)
 193 {
 194         int ret = 0;
 195         struct device_node *np;
 196         const u64 *cpu_rel_addr;
 197         unsigned long flags;
 198         int ioremappable;
 199         int hw_cpu = get_hard_smp_processor_id(cpu);
 200         struct epapr_spin_table __iomem *spin_table;
 201
 202         np = of_get_cpu_node(cpu, NULL);
 203         cpu_rel_addr = of_get_property(np, "cpu-release-addr", NULL);
 204         if (!cpu_rel_addr) {
 205                 pr_err("No cpu-release-addr for cpu %d\n", cpu);
 206                 return -ENOENT;
 207         }
 208
 209         /*
 210          * A secondary core could be in a spinloop in the bootpage
 211          * (0xfffff000), somewhere in highmem, or somewhere in lowmem.
 212          * The bootpage and highmem can be accessed via ioremap(), but
 213          * we need to directly access the spinloop if its in lowmem.
 214          */
 215         ioremappable = *cpu_rel_addr > virt_to_phys(high_memory);
 216
 217         /* Map the spin table */
 218         if (ioremappable)
 219                 spin_table = ioremap_prot(*cpu_rel_addr,
 220                         sizeof(struct epapr_spin_table), _PAGE_COHERENT);
 221         else
 222                 spin_table = phys_to_virt(*cpu_rel_addr);
 223
 224         local_irq_save(flags);
 225         hard_irq_disable();
 226
 227         if (qoriq_pm_ops)
 228                 qoriq_pm_ops->cpu_up_prepare(cpu);
 229
 230         /* if cpu is not spinning, reset it */
 231         if (read_spin_table_addr_l(spin_table) != 1) {
 232                 /*
 233                  * We don't set the BPTR register here since it already points
 234                  * to the boot page properly.
 235                  */
 236                 mpic_reset_core(cpu);
 237
 238                 /*
 239                  * wait until core is ready...
 240                  * We need to invalidate the stale data, in case the boot
 241                  * loader uses a cache-inhibited spin table.
 242                  */
 243                 if (!spin_event_timeout(
 244                                 read_spin_table_addr_l(spin_table) == 1,
 245                                 10000, 100)) {
 246                         pr_err("timeout waiting for cpu %d to reset\n",
 247                                 hw_cpu);
 248                         ret = -EAGAIN;
 249                         goto err;
 250                 }
 251         }
 252
 253         flush_spin_table(spin_table);
 254         out_be32(&spin_table->pir, hw_cpu);
 255 #ifdef CONFIG_PPC64
 256         out_be64((u64 *)(&spin_table->addr_h),
 257                 __pa(ppc_function_entry(generic_secondary_smp_init)));
 258 #else
 259         out_be32(&spin_table->addr_l, __pa(__early_start));
 260 #endif
 261         flush_spin_table(spin_table);
 262 err:
 263         local_irq_restore(flags);
 264
 265         if (ioremappable)
 266                 iounmap(spin_table);
 267
 268         return ret;
 269 }
 270
 271 static int smp_85xx_kick_cpu(int nr)
 272 {
 273         int ret = 0;
 274 #ifdef CONFIG_PPC64
 275         int primary = nr;
 276 #endif
 277
 278         WARN_ON(nr < 0 || nr >= num_possible_cpus());
 279
 280         pr_debug("kick CPU #%d\n", nr);
 281
 282 #ifdef CONFIG_PPC64
 283         if (threads_per_core == 2) {
 284                 if (WARN_ON_ONCE(!cpu_has_feature(CPU_FTR_SMT)))
 285                         return -ENOENT;
 286
 287                 booting_thread_hwid = cpu_thread_in_core(nr);
 288                 primary = cpu_first_thread_sibling(nr);
 289
 290                 if (qoriq_pm_ops)
 291                         qoriq_pm_ops->cpu_up_prepare(nr);
 292
 293                 /*
 294                  * If either thread in the core is online, use it to start
 295                  * the other.
 296                  */
 297                 if (cpu_online(primary)) {
 298                         smp_call_function_single(primary,
 299                                         wake_hw_thread, &nr, 1);
 300                         goto done;
 301                 } else if (cpu_online(primary + 1)) {
 302                         smp_call_function_single(primary + 1,
 303                                         wake_hw_thread, &nr, 1);
 304                         goto done;
 305                 }
 306
 307                 /*
 308                  * If getting here, it means both threads in the core are
 309                  * offline. So start the primary thread, then it will start
 310                  * the thread specified in booting_thread_hwid, the one
 311                  * corresponding to nr.
 312                  */
 313
 314         } else if (threads_per_core == 1) {
 315                 /*
 316                  * If one core has only one thread, set booting_thread_hwid to
 317                  * an invalid value.
 318                  */
 319                 booting_thread_hwid = INVALID_THREAD_HWID;
 320
 321         } else if (threads_per_core > 2) {
 322                 pr_err("Do not support more than 2 threads per CPU.");
 323                 return -EINVAL;
 324         }
 325
 326         ret = smp_85xx_start_cpu(primary);
 327         if (ret)
 328                 return ret;
 329
 330 done:
 331         paca[nr].cpu_start = 1;
 332         generic_set_cpu_up(nr);
 333
 334         return ret;
 335 #else
 336         ret = smp_85xx_start_cpu(nr);
 337         if (ret)
 338                 return ret;
 339
 340         generic_set_cpu_up(nr);
 341
 342         return ret;
 343 #endif
 344 }
 345
 346 struct smp_ops_t smp_85xx_ops = {
 347         .cause_nmi_ipi = NULL,
 348         .kick_cpu = smp_85xx_kick_cpu,
 349         .cpu_bootable = smp_generic_cpu_bootable,
 350 #ifdef CONFIG_HOTPLUG_CPU
 351         .cpu_disable    = generic_cpu_disable,
 352         .cpu_die        = generic_cpu_die,
 353 #endif
 354 #if defined(CONFIG_KEXEC_CORE) && !defined(CONFIG_PPC64)
 355         .give_timebase  = smp_generic_give_timebase,
 356         .take_timebase  = smp_generic_take_timebase,
 357 #endif
 358 };
 359
 360 #ifdef CONFIG_KEXEC_CORE
 361 #ifdef CONFIG_PPC32
 362 atomic_t kexec_down_cpus = ATOMIC_INIT(0);
 363
 364 void mpc85xx_smp_kexec_cpu_down(int crash_shutdown, int secondary)
 365 {
 366         local_irq_disable();
 367
 368         if (secondary) {
 369                 cur_cpu_spec->cpu_down_flush();
 370                 atomic_inc(&kexec_down_cpus);
 371                 /* loop forever */
 372                 while (1);
 373         }
 374 }
 375
 376 static void mpc85xx_smp_kexec_down(void *arg)
 377 {
 378         if (ppc_md.kexec_cpu_down)
 379                 ppc_md.kexec_cpu_down(0,1);
 380 }
 381 #else
 382 void mpc85xx_smp_kexec_cpu_down(int crash_shutdown, int secondary)
 383 {
 384         int cpu = smp_processor_id();
 385         int sibling = cpu_last_thread_sibling(cpu);
 386         bool notified = false;
 387         int disable_cpu;
 388         int disable_threadbit = 0;
 389         long start = mftb();
 390         long now;
 391
 392         local_irq_disable();
 393         hard_irq_disable();
 394         mpic_teardown_this_cpu(secondary);
 395
 396         if (cpu == crashing_cpu && cpu_thread_in_core(cpu) != 0) {
 397                 /*
 398                  * We enter the crash kernel on whatever cpu crashed,
 399                  * even if it's a secondary thread.  If that's the case,
 400                  * disable the corresponding primary thread.
 401                  */
 402                 disable_threadbit = 1;
 403                 disable_cpu = cpu_first_thread_sibling(cpu);
 404         } else if (sibling != crashing_cpu &&
 405                    cpu_thread_in_core(cpu) == 0 &&
 406                    cpu_thread_in_core(sibling) != 0) {
 407                 disable_threadbit = 2;
 408                 disable_cpu = sibling;
 409         }
 410
 411         if (disable_threadbit) {
 412                 while (paca[disable_cpu].kexec_state < KEXEC_STATE_REAL_MODE) {
 413                         barrier();
 414                         now = mftb();
 415                         if (!notified && now - start > 1000000) {
 416                                 pr_info("%s/%d: waiting for cpu %d to enter KEXEC_STATE_REAL_MODE (%d)\n",
 417                                         __func__, smp_processor_id(),
 418                                         disable_cpu,
 419                                         paca[disable_cpu].kexec_state);
 420                                 notified = true;
 421                         }
 422                 }
 423
 424                 if (notified) {
 425                         pr_info("%s: cpu %d done waiting\n",
 426                                 __func__, disable_cpu);
 427                 }
 428
 429                 mtspr(SPRN_TENC, disable_threadbit);
 430                 while (mfspr(SPRN_TENSR) & disable_threadbit)
 431                         cpu_relax();
 432         }
 433 }
 434 #endif
 435
 436 static void mpc85xx_smp_machine_kexec(struct kimage *image)
 437 {
 438 #ifdef CONFIG_PPC32
 439         int timeout = INT_MAX;
 440         int i, num_cpus = num_present_cpus();
 441
 442         if (image->type == KEXEC_TYPE_DEFAULT)
 443                 smp_call_function(mpc85xx_smp_kexec_down, NULL, 0);
 444
 445         while ( (atomic_read(&kexec_down_cpus) != (num_cpus - 1)) &&
 446                 ( timeout > 0 ) )
 447         {
 448                 timeout--;
 449         }
 450
 451         if ( !timeout )
 452                 printk(KERN_ERR "Unable to bring down secondary cpu(s)");
 453
 454         for_each_online_cpu(i)
 455         {
 456                 if ( i == smp_processor_id() ) continue;
 457                 mpic_reset_core(i);
 458         }
 459 #endif
 460
 461         default_machine_kexec(image);
 462 }
 463 #endif /* CONFIG_KEXEC_CORE */
 464
 465 static void smp_85xx_setup_cpu(int cpu_nr)
 466 {
 467         mpic_setup_this_cpu();
 468 }
 469
 470 void __init mpc85xx_smp_init(void)
 471 {
 472         struct device_node *np;
 473
 474
 475         np = of_find_node_by_type(NULL, "open-pic");
 476         if (np) {
 477                 smp_85xx_ops.probe = smp_mpic_probe;
 478                 smp_85xx_ops.setup_cpu = smp_85xx_setup_cpu;
 479                 smp_85xx_ops.message_pass = smp_mpic_message_pass;
 480         } else
 481                 smp_85xx_ops.setup_cpu = NULL;
 482
 483         if (cpu_has_feature(CPU_FTR_DBELL)) {
 484                 /*
 485                  * If left NULL, .message_pass defaults to
 486                  * smp_muxed_ipi_message_pass
 487                  */
 488                 smp_85xx_ops.message_pass = NULL;
 489                 smp_85xx_ops.cause_ipi = doorbell_global_ipi;
 490                 smp_85xx_ops.probe = NULL;
 491         }
 492
 493 #ifdef CONFIG_HOTPLUG_CPU
 494 #ifdef CONFIG_FSL_CORENET_RCPM
 495         fsl_rcpm_init();
 496 #endif
 497
 498 #ifdef CONFIG_FSL_PMC
 499         mpc85xx_setup_pmc();
 500 #endif
 501         if (qoriq_pm_ops) {
 502                 smp_85xx_ops.give_timebase = mpc85xx_give_timebase;
 503                 smp_85xx_ops.take_timebase = mpc85xx_take_timebase;
 504                 ppc_md.cpu_die = smp_85xx_mach_cpu_die;
 505                 smp_85xx_ops.cpu_die = qoriq_cpu_kill;
 506         }
 507 #endif
 508         smp_ops = &smp_85xx_ops;
 509
 510 #ifdef CONFIG_KEXEC_CORE
 511         ppc_md.kexec_cpu_down = mpc85xx_smp_kexec_cpu_down;
 512         ppc_md.machine_kexec = mpc85xx_smp_machine_kexec;
 513 #endif
 514 }