arch/mips/kernel/smp-cps.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2013 Imagination Technologies
   4  * Author: Paul Burton <paul.burton@mips.com>
   5  */
   6
   7 #include <linux/cpu.h>
   8 #include <linux/delay.h>
   9 #include <linux/io.h>
  10 #include <linux/memblock.h>
  11 #include <linux/sched/task_stack.h>
  12 #include <linux/sched/hotplug.h>
  13 #include <linux/slab.h>
  14 #include <linux/smp.h>
  15 #include <linux/types.h>
  16 #include <linux/irq.h>
  17
  18 #include <asm/bcache.h>
  19 #include <asm/mips-cps.h>
  20 #include <asm/mips_mt.h>
  21 #include <asm/mipsregs.h>
  22 #include <asm/pm-cps.h>
  23 #include <asm/r4kcache.h>
  24 #include <asm/regdef.h>
  25 #include <asm/smp.h>
  26 #include <asm/smp-cps.h>
  27 #include <asm/time.h>
  28 #include <asm/uasm.h>
  29
  30 #define BEV_VEC_SIZE    0x500
  31 #define BEV_VEC_ALIGN   0x1000
  32
  33 enum label_id {
  34         label_not_nmi = 1,
  35 };
  36
  37 UASM_L_LA(_not_nmi)
  38
  39 static DECLARE_BITMAP(core_power, NR_CPUS);
  40 static uint32_t core_entry_reg;
  41 static phys_addr_t cps_vec_pa;
  42
  43 struct core_boot_config *mips_cps_core_bootcfg;
  44
  45 static unsigned __init core_vpe_count(unsigned int cluster, unsigned core)
  46 {
  47         return min(smp_max_threads, mips_cps_numvps(cluster, core));
  48 }
  49
  50 static void __init *mips_cps_build_core_entry(void *addr)
  51 {
  52         extern void (*nmi_handler)(void);
  53         u32 *p = addr;
  54         u32 val;
  55         struct uasm_label labels[2];
  56         struct uasm_reloc relocs[2];
  57         struct uasm_label *l = labels;
  58         struct uasm_reloc *r = relocs;
  59
  60         memset(labels, 0, sizeof(labels));
  61         memset(relocs, 0, sizeof(relocs));
  62
  63         uasm_i_mfc0(&p, GPR_K0, C0_STATUS);
  64         UASM_i_LA(&p, GPR_T9, ST0_NMI);
  65         uasm_i_and(&p, GPR_K0, GPR_K0, GPR_T9);
  66
  67         uasm_il_bnez(&p, &r, GPR_K0, label_not_nmi);
  68         uasm_i_nop(&p);
  69         UASM_i_LA(&p, GPR_K0, (long)&nmi_handler);
  70
  71         uasm_l_not_nmi(&l, p);
  72
  73         val = CAUSEF_IV;
  74         uasm_i_lui(&p, GPR_K0, val >> 16);
  75         uasm_i_ori(&p, GPR_K0, GPR_K0, val & 0xffff);
  76         uasm_i_mtc0(&p, GPR_K0, C0_CAUSE);
  77         val = ST0_CU1 | ST0_CU0 | ST0_BEV | ST0_KX_IF_64;
  78         uasm_i_lui(&p, GPR_K0, val >> 16);
  79         uasm_i_ori(&p, GPR_K0, GPR_K0, val & 0xffff);
  80         uasm_i_mtc0(&p, GPR_K0, C0_STATUS);
  81         uasm_i_ehb(&p);
  82         uasm_i_ori(&p, GPR_A0, 0, read_c0_config() & CONF_CM_CMASK);
  83         UASM_i_LA(&p, GPR_A1, (long)mips_gcr_base);
  84 #if defined(KBUILD_64BIT_SYM32) || defined(CONFIG_32BIT)
  85         UASM_i_LA(&p, GPR_T9, CKSEG1ADDR(__pa_symbol(mips_cps_core_boot)));
  86 #else
  87         UASM_i_LA(&p, GPR_T9, TO_UNCAC(__pa_symbol(mips_cps_core_boot)));
  88 #endif
  89         uasm_i_jr(&p, GPR_T9);
  90         uasm_i_nop(&p);
  91
  92         uasm_resolve_relocs(relocs, labels);
  93
  94         return p;
  95 }
  96
  97 static int __init allocate_cps_vecs(void)
  98 {
  99         /* Try to allocate in KSEG1 first */
 100         cps_vec_pa = memblock_phys_alloc_range(BEV_VEC_SIZE, BEV_VEC_ALIGN,
 101                                                 0x0, CSEGX_SIZE - 1);
 102
 103         if (cps_vec_pa)
 104                 core_entry_reg = CKSEG1ADDR(cps_vec_pa) &
 105                                         CM_GCR_Cx_RESET_BASE_BEVEXCBASE;
 106
 107         if (!cps_vec_pa && mips_cm_is64) {
 108                 cps_vec_pa = memblock_phys_alloc_range(BEV_VEC_SIZE, BEV_VEC_ALIGN,
 109                                                         0x0, SZ_4G - 1);
 110                 if (cps_vec_pa)
 111                         core_entry_reg = (cps_vec_pa & CM_GCR_Cx_RESET_BASE_BEVEXCBASE) |
 112                                         CM_GCR_Cx_RESET_BASE_MODE;
 113         }
 114
 115         if (!cps_vec_pa)
 116                 return -ENOMEM;
 117
 118         return 0;
 119 }
 120
 121 static void __init setup_cps_vecs(void)
 122 {
 123         void *cps_vec;
 124
 125         cps_vec = (void *)CKSEG1ADDR_OR_64BIT(cps_vec_pa);
 126         mips_cps_build_core_entry(cps_vec);
 127
 128         memcpy(cps_vec + 0x200, &excep_tlbfill, 0x80);
 129         memcpy(cps_vec + 0x280, &excep_xtlbfill, 0x80);
 130         memcpy(cps_vec + 0x300, &excep_cache, 0x80);
 131         memcpy(cps_vec + 0x380, &excep_genex, 0x80);
 132         memcpy(cps_vec + 0x400, &excep_intex, 0x80);
 133         memcpy(cps_vec + 0x480, &excep_ejtag, 0x80);
 134
 135         /* Make sure no prefetched data in cache */
 136         blast_inv_dcache_range(CKSEG0ADDR_OR_64BIT(cps_vec_pa), CKSEG0ADDR_OR_64BIT(cps_vec_pa) + BEV_VEC_SIZE);
 137         bc_inv(CKSEG0ADDR_OR_64BIT(cps_vec_pa), BEV_VEC_SIZE);
 138         __sync();
 139 }
 140
 141 static void __init cps_smp_setup(void)
 142 {
 143         unsigned int nclusters, ncores, nvpes, core_vpes;
 144         int cl, c, v;
 145
 146         /* Detect & record VPE topology */
 147         nvpes = 0;
 148         nclusters = mips_cps_numclusters();
 149         pr_info("%s topology ", cpu_has_mips_r6 ? "VP" : "VPE");
 150         for (cl = 0; cl < nclusters; cl++) {
 151                 if (cl > 0)
 152                         pr_cont(",");
 153                 pr_cont("{");
 154
 155                 ncores = mips_cps_numcores(cl);
 156                 for (c = 0; c < ncores; c++) {
 157                         core_vpes = core_vpe_count(cl, c);
 158
 159                         if (c > 0)
 160                                 pr_cont(",");
 161                         pr_cont("%u", core_vpes);
 162
 163                         /* Use the number of VPEs in cluster 0 core 0 for smp_num_siblings */
 164                         if (!cl && !c)
 165                                 smp_num_siblings = core_vpes;
 166
 167                         for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {
 168                                 cpu_set_cluster(&cpu_data[nvpes + v], cl);
 169                                 cpu_set_core(&cpu_data[nvpes + v], c);
 170                                 cpu_set_vpe_id(&cpu_data[nvpes + v], v);
 171                         }
 172
 173                         nvpes += core_vpes;
 174                 }
 175
 176                 pr_cont("}");
 177         }
 178         pr_cont(" total %u\n", nvpes);
 179
 180         /* Indicate present CPUs (CPU being synonymous with VPE) */
 181         for (v = 0; v < min_t(unsigned, nvpes, NR_CPUS); v++) {
 182                 set_cpu_possible(v, cpu_cluster(&cpu_data[v]) == 0);
 183                 set_cpu_present(v, cpu_cluster(&cpu_data[v]) == 0);
 184                 __cpu_number_map[v] = v;
 185                 __cpu_logical_map[v] = v;
 186         }
 187
 188         /* Set a coherent default CCA (CWB) */
 189         change_c0_config(CONF_CM_CMASK, 0x5);
 190
 191         /* Core 0 is powered up (we're running on it) */
 192         bitmap_set(core_power, 0, 1);
 193
 194         /* Initialise core 0 */
 195         mips_cps_core_init();
 196
 197         /* Make core 0 coherent with everything */
 198         write_gcr_cl_coherence(0xff);
 199
 200         if (allocate_cps_vecs())
 201                 pr_err("Failed to allocate CPS vectors\n");
 202
 203         if (core_entry_reg && mips_cm_revision() >= CM_REV_CM3)
 204                 write_gcr_bev_base(core_entry_reg);
 205
 206 #ifdef CONFIG_MIPS_MT_FPAFF
 207         /* If we have an FPU, enroll ourselves in the FPU-full mask */
 208         if (cpu_has_fpu)
 209                 cpumask_set_cpu(0, &mt_fpu_cpumask);
 210 #endif /* CONFIG_MIPS_MT_FPAFF */
 211 }
 212
 213 static void __init cps_prepare_cpus(unsigned int max_cpus)
 214 {
 215         unsigned ncores, core_vpes, c, cca;
 216         bool cca_unsuitable, cores_limited;
 217
 218         mips_mt_set_cpuoptions();
 219
 220         if (!core_entry_reg) {
 221                 pr_err("core_entry address unsuitable, disabling smp-cps\n");
 222                 goto err_out;
 223         }
 224
 225         /* Detect whether the CCA is unsuited to multi-core SMP */
 226         cca = read_c0_config() & CONF_CM_CMASK;
 227         switch (cca) {
 228         case 0x4: /* CWBE */
 229         case 0x5: /* CWB */
 230                 /* The CCA is coherent, multi-core is fine */
 231                 cca_unsuitable = false;
 232                 break;
 233
 234         default:
 235                 /* CCA is not coherent, multi-core is not usable */
 236                 cca_unsuitable = true;
 237         }
 238
 239         /* Warn the user if the CCA prevents multi-core */
 240         cores_limited = false;
 241         if (cca_unsuitable || cpu_has_dc_aliases) {
 242                 for_each_present_cpu(c) {
 243                         if (cpus_are_siblings(smp_processor_id(), c))
 244                                 continue;
 245
 246                         set_cpu_present(c, false);
 247                         cores_limited = true;
 248                 }
 249         }
 250         if (cores_limited)
 251                 pr_warn("Using only one core due to %s%s%s\n",
 252                         cca_unsuitable ? "unsuitable CCA" : "",
 253                         (cca_unsuitable && cpu_has_dc_aliases) ? " & " : "",
 254                         cpu_has_dc_aliases ? "dcache aliasing" : "");
 255
 256         setup_cps_vecs();
 257
 258         /* Allocate core boot configuration structs */
 259         ncores = mips_cps_numcores(0);
 260         mips_cps_core_bootcfg = kcalloc(ncores, sizeof(*mips_cps_core_bootcfg),
 261                                         GFP_KERNEL);
 262         if (!mips_cps_core_bootcfg) {
 263                 pr_err("Failed to allocate boot config for %u cores\n", ncores);
 264                 goto err_out;
 265         }
 266
 267         /* Allocate VPE boot configuration structs */
 268         for (c = 0; c < ncores; c++) {
 269                 core_vpes = core_vpe_count(0, c);
 270                 mips_cps_core_bootcfg[c].vpe_config = kcalloc(core_vpes,
 271                                 sizeof(*mips_cps_core_bootcfg[c].vpe_config),
 272                                 GFP_KERNEL);
 273                 if (!mips_cps_core_bootcfg[c].vpe_config) {
 274                         pr_err("Failed to allocate %u VPE boot configs\n",
 275                                core_vpes);
 276                         goto err_out;
 277                 }
 278         }
 279
 280         /* Mark this CPU as booted */
 281         atomic_set(&mips_cps_core_bootcfg[cpu_core(&current_cpu_data)].vpe_mask,
 282                    1 << cpu_vpe_id(&current_cpu_data));
 283
 284         return;
 285 err_out:
 286         /* Clean up allocations */
 287         if (mips_cps_core_bootcfg) {
 288                 for (c = 0; c < ncores; c++)
 289                         kfree(mips_cps_core_bootcfg[c].vpe_config);
 290                 kfree(mips_cps_core_bootcfg);
 291                 mips_cps_core_bootcfg = NULL;
 292         }
 293
 294         /* Effectively disable SMP by declaring CPUs not present */
 295         for_each_possible_cpu(c) {
 296                 if (c == 0)
 297                         continue;
 298                 set_cpu_present(c, false);
 299         }
 300 }
 301
 302 static void boot_core(unsigned int core, unsigned int vpe_id)
 303 {
 304         u32 stat, seq_state;
 305         unsigned timeout;
 306
 307         /* Select the appropriate core */
 308         mips_cm_lock_other(0, core, 0, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
 309
 310         /* Set its reset vector */
 311         write_gcr_co_reset_base(core_entry_reg);
 312
 313         /* Ensure its coherency is disabled */
 314         write_gcr_co_coherence(0);
 315
 316         /* Start it with the legacy memory map and exception base */
 317         write_gcr_co_reset_ext_base(CM_GCR_Cx_RESET_EXT_BASE_UEB);
 318
 319         /* Ensure the core can access the GCRs */
 320         if (mips_cm_revision() < CM_REV_CM3)
 321                 set_gcr_access(1 << core);
 322         else
 323                 set_gcr_access_cm3(1 << core);
 324
 325         if (mips_cpc_present()) {
 326                 /* Reset the core */
 327                 mips_cpc_lock_other(core);
 328
 329                 if (mips_cm_revision() >= CM_REV_CM3) {
 330                         /* Run only the requested VP following the reset */
 331                         write_cpc_co_vp_stop(0xf);
 332                         write_cpc_co_vp_run(1 << vpe_id);
 333
 334                         /*
 335                          * Ensure that the VP_RUN register is written before the
 336                          * core leaves reset.
 337                          */
 338                         wmb();
 339                 }
 340
 341                 write_cpc_co_cmd(CPC_Cx_CMD_RESET);
 342
 343                 timeout = 100;
 344                 while (true) {
 345                         stat = read_cpc_co_stat_conf();
 346                         seq_state = stat & CPC_Cx_STAT_CONF_SEQSTATE;
 347                         seq_state >>= __ffs(CPC_Cx_STAT_CONF_SEQSTATE);
 348
 349                         /* U6 == coherent execution, ie. the core is up */
 350                         if (seq_state == CPC_Cx_STAT_CONF_SEQSTATE_U6)
 351                                 break;
 352
 353                         /* Delay a little while before we start warning */
 354                         if (timeout) {
 355                                 timeout--;
 356                                 mdelay(10);
 357                                 continue;
 358                         }
 359
 360                         pr_warn("Waiting for core %u to start... STAT_CONF=0x%x\n",
 361                                 core, stat);
 362                         mdelay(1000);
 363                 }
 364
 365                 mips_cpc_unlock_other();
 366         } else {
 367                 /* Take the core out of reset */
 368                 write_gcr_co_reset_release(0);
 369         }
 370
 371         mips_cm_unlock_other();
 372
 373         /* The core is now powered up */
 374         bitmap_set(core_power, core, 1);
 375 }
 376
 377 static void remote_vpe_boot(void *dummy)
 378 {
 379         unsigned core = cpu_core(&current_cpu_data);
 380         struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
 381
 382         mips_cps_boot_vpes(core_cfg, cpu_vpe_id(&current_cpu_data));
 383 }
 384
 385 static int cps_boot_secondary(int cpu, struct task_struct *idle)
 386 {
 387         unsigned core = cpu_core(&cpu_data[cpu]);
 388         unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
 389         struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
 390         struct vpe_boot_config *vpe_cfg = &core_cfg->vpe_config[vpe_id];
 391         unsigned int remote;
 392         int err;
 393
 394         /* We don't yet support booting CPUs in other clusters */
 395         if (cpu_cluster(&cpu_data[cpu]) != cpu_cluster(&raw_current_cpu_data))
 396                 return -ENOSYS;
 397
 398         vpe_cfg->pc = (unsigned long)&smp_bootstrap;
 399         vpe_cfg->sp = __KSTK_TOS(idle);
 400         vpe_cfg->gp = (unsigned long)task_thread_info(idle);
 401
 402         atomic_or(1 << cpu_vpe_id(&cpu_data[cpu]), &core_cfg->vpe_mask);
 403
 404         preempt_disable();
 405
 406         if (!test_bit(core, core_power)) {
 407                 /* Boot a VPE on a powered down core */
 408                 boot_core(core, vpe_id);
 409                 goto out;
 410         }
 411
 412         if (cpu_has_vp) {
 413                 mips_cm_lock_other(0, core, vpe_id, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
 414                 write_gcr_co_reset_base(core_entry_reg);
 415                 mips_cm_unlock_other();
 416         }
 417
 418         if (!cpus_are_siblings(cpu, smp_processor_id())) {
 419                 /* Boot a VPE on another powered up core */
 420                 for (remote = 0; remote < NR_CPUS; remote++) {
 421                         if (!cpus_are_siblings(cpu, remote))
 422                                 continue;
 423                         if (cpu_online(remote))
 424                                 break;
 425                 }
 426                 if (remote >= NR_CPUS) {
 427                         pr_crit("No online CPU in core %u to start CPU%d\n",
 428                                 core, cpu);
 429                         goto out;
 430                 }
 431
 432                 err = smp_call_function_single(remote, remote_vpe_boot,
 433                                                NULL, 1);
 434                 if (err)
 435                         panic("Failed to call remote CPU\n");
 436                 goto out;
 437         }
 438
 439         BUG_ON(!cpu_has_mipsmt && !cpu_has_vp);
 440
 441         /* Boot a VPE on this core */
 442         mips_cps_boot_vpes(core_cfg, vpe_id);
 443 out:
 444         preempt_enable();
 445         return 0;
 446 }
 447
 448 static void cps_init_secondary(void)
 449 {
 450         int core = cpu_core(&current_cpu_data);
 451
 452         /* Disable MT - we only want to run 1 TC per VPE */
 453         if (cpu_has_mipsmt)
 454                 dmt();
 455
 456         if (mips_cm_revision() >= CM_REV_CM3) {
 457                 unsigned int ident = read_gic_vl_ident();
 458
 459                 /*
 460                  * Ensure that our calculation of the VP ID matches up with
 461                  * what the GIC reports, otherwise we'll have configured
 462                  * interrupts incorrectly.
 463                  */
 464                 BUG_ON(ident != mips_cm_vp_id(smp_processor_id()));
 465         }
 466
 467         if (core > 0 && !read_gcr_cl_coherence())
 468                 pr_warn("Core %u is not in coherent domain\n", core);
 469
 470         if (cpu_has_veic)
 471                 clear_c0_status(ST0_IM);
 472         else
 473                 change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 |
 474                                          STATUSF_IP4 | STATUSF_IP5 |
 475                                          STATUSF_IP6 | STATUSF_IP7);
 476 }
 477
 478 static void cps_smp_finish(void)
 479 {
 480         write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency / HZ));
 481
 482 #ifdef CONFIG_MIPS_MT_FPAFF
 483         /* If we have an FPU, enroll ourselves in the FPU-full mask */
 484         if (cpu_has_fpu)
 485                 cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask);
 486 #endif /* CONFIG_MIPS_MT_FPAFF */
 487
 488         local_irq_enable();
 489 }
 490
 491 #if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_KEXEC_CORE)
 492
 493 enum cpu_death {
 494         CPU_DEATH_HALT,
 495         CPU_DEATH_POWER,
 496 };
 497
 498 static void cps_shutdown_this_cpu(enum cpu_death death)
 499 {
 500         unsigned int cpu, core, vpe_id;
 501
 502         cpu = smp_processor_id();
 503         core = cpu_core(&cpu_data[cpu]);
 504
 505         if (death == CPU_DEATH_HALT) {
 506                 vpe_id = cpu_vpe_id(&cpu_data[cpu]);
 507
 508                 pr_debug("Halting core %d VP%d\n", core, vpe_id);
 509                 if (cpu_has_mipsmt) {
 510                         /* Halt this TC */
 511                         write_c0_tchalt(TCHALT_H);
 512                         instruction_hazard();
 513                 } else if (cpu_has_vp) {
 514                         write_cpc_cl_vp_stop(1 << vpe_id);
 515
 516                         /* Ensure that the VP_STOP register is written */
 517                         wmb();
 518                 }
 519         } else {
 520                 if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
 521                         pr_debug("Gating power to core %d\n", core);
 522                         /* Power down the core */
 523                         cps_pm_enter_state(CPS_PM_POWER_GATED);
 524                 }
 525         }
 526 }
 527
 528 #ifdef CONFIG_KEXEC_CORE
 529
 530 static void cps_kexec_nonboot_cpu(void)
 531 {
 532         if (cpu_has_mipsmt || cpu_has_vp)
 533                 cps_shutdown_this_cpu(CPU_DEATH_HALT);
 534         else
 535                 cps_shutdown_this_cpu(CPU_DEATH_POWER);
 536 }
 537
 538 #endif /* CONFIG_KEXEC_CORE */
 539
 540 #endif /* CONFIG_HOTPLUG_CPU || CONFIG_KEXEC_CORE */
 541
 542 #ifdef CONFIG_HOTPLUG_CPU
 543
 544 static int cps_cpu_disable(void)
 545 {
 546         unsigned cpu = smp_processor_id();
 547         struct core_boot_config *core_cfg;
 548
 549         if (!cps_pm_support_state(CPS_PM_POWER_GATED))
 550                 return -EINVAL;
 551
 552         core_cfg = &mips_cps_core_bootcfg[cpu_core(&current_cpu_data)];
 553         atomic_sub(1 << cpu_vpe_id(&current_cpu_data), &core_cfg->vpe_mask);
 554         smp_mb__after_atomic();
 555         set_cpu_online(cpu, false);
 556         calculate_cpu_foreign_map();
 557         irq_migrate_all_off_this_cpu();
 558
 559         return 0;
 560 }
 561
 562 static unsigned cpu_death_sibling;
 563 static enum cpu_death cpu_death;
 564
 565 void play_dead(void)
 566 {
 567         unsigned int cpu;
 568
 569         local_irq_disable();
 570         idle_task_exit();
 571         cpu = smp_processor_id();
 572         cpu_death = CPU_DEATH_POWER;
 573
 574         pr_debug("CPU%d going offline\n", cpu);
 575
 576         if (cpu_has_mipsmt || cpu_has_vp) {
 577                 /* Look for another online VPE within the core */
 578                 for_each_online_cpu(cpu_death_sibling) {
 579                         if (!cpus_are_siblings(cpu, cpu_death_sibling))
 580                                 continue;
 581
 582                         /*
 583                          * There is an online VPE within the core. Just halt
 584                          * this TC and leave the core alone.
 585                          */
 586                         cpu_death = CPU_DEATH_HALT;
 587                         break;
 588                 }
 589         }
 590
 591         cpuhp_ap_report_dead();
 592
 593         cps_shutdown_this_cpu(cpu_death);
 594
 595         /* This should never be reached */
 596         panic("Failed to offline CPU %u", cpu);
 597 }
 598
 599 static void wait_for_sibling_halt(void *ptr_cpu)
 600 {
 601         unsigned cpu = (unsigned long)ptr_cpu;
 602         unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
 603         unsigned halted;
 604         unsigned long flags;
 605
 606         do {
 607                 local_irq_save(flags);
 608                 settc(vpe_id);
 609                 halted = read_tc_c0_tchalt();
 610                 local_irq_restore(flags);
 611         } while (!(halted & TCHALT_H));
 612 }
 613
 614 static void cps_cpu_die(unsigned int cpu) { }
 615
 616 static void cps_cleanup_dead_cpu(unsigned cpu)
 617 {
 618         unsigned core = cpu_core(&cpu_data[cpu]);
 619         unsigned int vpe_id = cpu_vpe_id(&cpu_data[cpu]);
 620         ktime_t fail_time;
 621         unsigned stat;
 622         int err;
 623
 624         /*
 625          * Now wait for the CPU to actually offline. Without doing this that
 626          * offlining may race with one or more of:
 627          *
 628          *   - Onlining the CPU again.
 629          *   - Powering down the core if another VPE within it is offlined.
 630          *   - A sibling VPE entering a non-coherent state.
 631          *
 632          * In the non-MT halt case (ie. infinite loop) the CPU is doing nothing
 633          * with which we could race, so do nothing.
 634          */
 635         if (cpu_death == CPU_DEATH_POWER) {
 636                 /*
 637                  * Wait for the core to enter a powered down or clock gated
 638                  * state, the latter happening when a JTAG probe is connected
 639                  * in which case the CPC will refuse to power down the core.
 640                  */
 641                 fail_time = ktime_add_ms(ktime_get(), 2000);
 642                 do {
 643                         mips_cm_lock_other(0, core, 0, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
 644                         mips_cpc_lock_other(core);
 645                         stat = read_cpc_co_stat_conf();
 646                         stat &= CPC_Cx_STAT_CONF_SEQSTATE;
 647                         stat >>= __ffs(CPC_Cx_STAT_CONF_SEQSTATE);
 648                         mips_cpc_unlock_other();
 649                         mips_cm_unlock_other();
 650
 651                         if (stat == CPC_Cx_STAT_CONF_SEQSTATE_D0 ||
 652                             stat == CPC_Cx_STAT_CONF_SEQSTATE_D2 ||
 653                             stat == CPC_Cx_STAT_CONF_SEQSTATE_U2)
 654                                 break;
 655
 656                         /*
 657                          * The core ought to have powered down, but didn't &
 658                          * now we don't really know what state it's in. It's
 659                          * likely that its _pwr_up pin has been wired to logic
 660                          * 1 & it powered back up as soon as we powered it
 661                          * down...
 662                          *
 663                          * The best we can do is warn the user & continue in
 664                          * the hope that the core is doing nothing harmful &
 665                          * might behave properly if we online it later.
 666                          */
 667                         if (WARN(ktime_after(ktime_get(), fail_time),
 668                                  "CPU%u hasn't powered down, seq. state %u\n",
 669                                  cpu, stat))
 670                                 break;
 671                 } while (1);
 672
 673                 /* Indicate the core is powered off */
 674                 bitmap_clear(core_power, core, 1);
 675         } else if (cpu_has_mipsmt) {
 676                 /*
 677                  * Have a CPU with access to the offlined CPUs registers wait
 678                  * for its TC to halt.
 679                  */
 680                 err = smp_call_function_single(cpu_death_sibling,
 681                                                wait_for_sibling_halt,
 682                                                (void *)(unsigned long)cpu, 1);
 683                 if (err)
 684                         panic("Failed to call remote sibling CPU\n");
 685         } else if (cpu_has_vp) {
 686                 do {
 687                         mips_cm_lock_other(0, core, vpe_id, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
 688                         stat = read_cpc_co_vp_running();
 689                         mips_cm_unlock_other();
 690                 } while (stat & (1 << vpe_id));
 691         }
 692 }
 693
 694 #endif /* CONFIG_HOTPLUG_CPU */
 695
 696 static const struct plat_smp_ops cps_smp_ops = {
 697         .smp_setup              = cps_smp_setup,
 698         .prepare_cpus           = cps_prepare_cpus,
 699         .boot_secondary         = cps_boot_secondary,
 700         .init_secondary         = cps_init_secondary,
 701         .smp_finish             = cps_smp_finish,
 702         .send_ipi_single        = mips_smp_send_ipi_single,
 703         .send_ipi_mask          = mips_smp_send_ipi_mask,
 704 #ifdef CONFIG_HOTPLUG_CPU
 705         .cpu_disable            = cps_cpu_disable,
 706         .cpu_die                = cps_cpu_die,
 707         .cleanup_dead_cpu       = cps_cleanup_dead_cpu,
 708 #endif
 709 #ifdef CONFIG_KEXEC_CORE
 710         .kexec_nonboot_cpu      = cps_kexec_nonboot_cpu,
 711 #endif
 712 };
 713
 714 bool mips_cps_smp_in_use(void)
 715 {
 716         extern const struct plat_smp_ops *mp_ops;
 717         return mp_ops == &cps_smp_ops;
 718 }
 719
 720 int register_cps_smp_ops(void)
 721 {
 722         if (!mips_cm_present()) {
 723                 pr_warn("MIPS CPS SMP unable to proceed without a CM\n");
 724                 return -ENODEV;
 725         }
 726
 727         /* check we have a GIC - we need one for IPIs */
 728         if (!(read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX)) {
 729                 pr_warn("MIPS CPS SMP unable to proceed without a GIC\n");
 730                 return -ENODEV;
 731         }
 732
 733         register_smp_ops(&cps_smp_ops);
 734         return 0;
 735 }