1 /* 2 * Copyright (C) 2013 Imagination Technologies 3 * Author: Paul Burton <paul.burton@imgtec.com> 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License as published by the 7 * Free Software Foundation; either version 2 of the License, or (at your 8 * option) any later version. 9 */ 10 11 #include <linux/delay.h> 12 #include <linux/io.h> 13 #include <linux/irqchip/mips-gic.h> 14 #include <linux/sched/task_stack.h> 15 #include <linux/sched/hotplug.h> 16 #include <linux/slab.h> 17 #include <linux/smp.h> 18 #include <linux/types.h> 19 20 #include <asm/bcache.h> 21 #include <asm/mips-cm.h> 22 #include <asm/mips-cpc.h> 23 #include <asm/mips_mt.h> 24 #include <asm/mipsregs.h> 25 #include <asm/pm-cps.h> 26 #include <asm/r4kcache.h> 27 #include <asm/smp-cps.h> 28 #include <asm/time.h> 29 #include <asm/uasm.h> 30 31 static bool threads_disabled; 32 static DECLARE_BITMAP(core_power, NR_CPUS); 33 34 struct core_boot_config *mips_cps_core_bootcfg; 35 36 static int __init setup_nothreads(char *s) 37 { 38 threads_disabled = true; 39 return 0; 40 } 41 early_param("nothreads", setup_nothreads); 42 43 static unsigned core_vpe_count(unsigned core) 44 { 45 unsigned cfg; 46 47 if (threads_disabled) 48 return 1; 49 50 if ((!IS_ENABLED(CONFIG_MIPS_MT_SMP) || !cpu_has_mipsmt) 51 && (!IS_ENABLED(CONFIG_CPU_MIPSR6) || !cpu_has_vp)) 52 return 1; 53 54 mips_cm_lock_other(core, 0); 55 cfg = read_gcr_co_config() & CM_GCR_Cx_CONFIG_PVPE_MSK; 56 mips_cm_unlock_other(); 57 return (cfg >> CM_GCR_Cx_CONFIG_PVPE_SHF) + 1; 58 } 59 60 static void __init cps_smp_setup(void) 61 { 62 unsigned int ncores, nvpes, core_vpes; 63 unsigned long core_entry; 64 int c, v; 65 66 /* Detect & record VPE topology */ 67 ncores = mips_cm_numcores(); 68 pr_info("%s topology ", cpu_has_mips_r6 ? "VP" : "VPE"); 69 for (c = nvpes = 0; c < ncores; c++) { 70 core_vpes = core_vpe_count(c); 71 pr_cont("%c%u", c ? ',' : '{', core_vpes); 72 73 /* Use the number of VPEs in core 0 for smp_num_siblings */ 74 if (!c) 75 smp_num_siblings = core_vpes; 76 77 for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) { 78 cpu_data[nvpes + v].core = c; 79 #if defined(CONFIG_MIPS_MT_SMP) || defined(CONFIG_CPU_MIPSR6) 80 cpu_data[nvpes + v].vpe_id = v; 81 #endif 82 } 83 84 nvpes += core_vpes; 85 } 86 pr_cont("} total %u\n", nvpes); 87 88 /* Indicate present CPUs (CPU being synonymous with VPE) */ 89 for (v = 0; v < min_t(unsigned, nvpes, NR_CPUS); v++) { 90 set_cpu_possible(v, true); 91 set_cpu_present(v, true); 92 __cpu_number_map[v] = v; 93 __cpu_logical_map[v] = v; 94 } 95 96 /* Set a coherent default CCA (CWB) */ 97 change_c0_config(CONF_CM_CMASK, 0x5); 98 99 /* Core 0 is powered up (we're running on it) */ 100 bitmap_set(core_power, 0, 1); 101 102 /* Initialise core 0 */ 103 mips_cps_core_init(); 104 105 /* Make core 0 coherent with everything */ 106 write_gcr_cl_coherence(0xff); 107 108 if (mips_cm_revision() >= CM_REV_CM3) { 109 core_entry = CKSEG1ADDR((unsigned long)mips_cps_core_entry); 110 write_gcr_bev_base(core_entry); 111 } 112 113 #ifdef CONFIG_MIPS_MT_FPAFF 114 /* If we have an FPU, enroll ourselves in the FPU-full mask */ 115 if (cpu_has_fpu) 116 cpumask_set_cpu(0, &mt_fpu_cpumask); 117 #endif /* CONFIG_MIPS_MT_FPAFF */ 118 } 119 120 static void __init cps_prepare_cpus(unsigned int max_cpus) 121 { 122 unsigned ncores, core_vpes, c, cca; 123 bool cca_unsuitable; 124 u32 *entry_code; 125 126 mips_mt_set_cpuoptions(); 127 128 /* Detect whether the CCA is unsuited to multi-core SMP */ 129 cca = read_c0_config() & CONF_CM_CMASK; 130 switch (cca) { 131 case 0x4: /* CWBE */ 132 case 0x5: /* CWB */ 133 /* The CCA is coherent, multi-core is fine */ 134 cca_unsuitable = false; 135 break; 136 137 default: 138 /* CCA is not coherent, multi-core is not usable */ 139 cca_unsuitable = true; 140 } 141 142 /* Warn the user if the CCA prevents multi-core */ 143 ncores = mips_cm_numcores(); 144 if (cca_unsuitable && ncores > 1) { 145 pr_warn("Using only one core due to unsuitable CCA 0x%x\n", 146 cca); 147 148 for_each_present_cpu(c) { 149 if (cpu_data[c].core) 150 set_cpu_present(c, false); 151 } 152 } 153 154 /* 155 * Patch the start of mips_cps_core_entry to provide: 156 * 157 * s0 = kseg0 CCA 158 */ 159 entry_code = (u32 *)&mips_cps_core_entry; 160 uasm_i_addiu(&entry_code, 16, 0, cca); 161 blast_dcache_range((unsigned long)&mips_cps_core_entry, 162 (unsigned long)entry_code); 163 bc_wback_inv((unsigned long)&mips_cps_core_entry, 164 (void *)entry_code - (void *)&mips_cps_core_entry); 165 __sync(); 166 167 /* Allocate core boot configuration structs */ 168 mips_cps_core_bootcfg = kcalloc(ncores, sizeof(*mips_cps_core_bootcfg), 169 GFP_KERNEL); 170 if (!mips_cps_core_bootcfg) { 171 pr_err("Failed to allocate boot config for %u cores\n", ncores); 172 goto err_out; 173 } 174 175 /* Allocate VPE boot configuration structs */ 176 for (c = 0; c < ncores; c++) { 177 core_vpes = core_vpe_count(c); 178 mips_cps_core_bootcfg[c].vpe_config = kcalloc(core_vpes, 179 sizeof(*mips_cps_core_bootcfg[c].vpe_config), 180 GFP_KERNEL); 181 if (!mips_cps_core_bootcfg[c].vpe_config) { 182 pr_err("Failed to allocate %u VPE boot configs\n", 183 core_vpes); 184 goto err_out; 185 } 186 } 187 188 /* Mark this CPU as booted */ 189 atomic_set(&mips_cps_core_bootcfg[current_cpu_data.core].vpe_mask, 190 1 << cpu_vpe_id(¤t_cpu_data)); 191 192 return; 193 err_out: 194 /* Clean up allocations */ 195 if (mips_cps_core_bootcfg) { 196 for (c = 0; c < ncores; c++) 197 kfree(mips_cps_core_bootcfg[c].vpe_config); 198 kfree(mips_cps_core_bootcfg); 199 mips_cps_core_bootcfg = NULL; 200 } 201 202 /* Effectively disable SMP by declaring CPUs not present */ 203 for_each_possible_cpu(c) { 204 if (c == 0) 205 continue; 206 set_cpu_present(c, false); 207 } 208 } 209 210 static void boot_core(unsigned int core, unsigned int vpe_id) 211 { 212 u32 access, stat, seq_state; 213 unsigned timeout; 214 215 /* Select the appropriate core */ 216 mips_cm_lock_other(core, 0); 217 218 /* Set its reset vector */ 219 write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry)); 220 221 /* Ensure its coherency is disabled */ 222 write_gcr_co_coherence(0); 223 224 /* Start it with the legacy memory map and exception base */ 225 write_gcr_co_reset_ext_base(CM_GCR_RESET_EXT_BASE_UEB); 226 227 /* Ensure the core can access the GCRs */ 228 access = read_gcr_access(); 229 access |= 1 << (CM_GCR_ACCESS_ACCESSEN_SHF + core); 230 write_gcr_access(access); 231 232 if (mips_cpc_present()) { 233 /* Reset the core */ 234 mips_cpc_lock_other(core); 235 236 if (mips_cm_revision() >= CM_REV_CM3) { 237 /* Run only the requested VP following the reset */ 238 write_cpc_co_vp_stop(0xf); 239 write_cpc_co_vp_run(1 << vpe_id); 240 241 /* 242 * Ensure that the VP_RUN register is written before the 243 * core leaves reset. 244 */ 245 wmb(); 246 } 247 248 write_cpc_co_cmd(CPC_Cx_CMD_RESET); 249 250 timeout = 100; 251 while (true) { 252 stat = read_cpc_co_stat_conf(); 253 seq_state = stat & CPC_Cx_STAT_CONF_SEQSTATE_MSK; 254 255 /* U6 == coherent execution, ie. the core is up */ 256 if (seq_state == CPC_Cx_STAT_CONF_SEQSTATE_U6) 257 break; 258 259 /* Delay a little while before we start warning */ 260 if (timeout) { 261 timeout--; 262 mdelay(10); 263 continue; 264 } 265 266 pr_warn("Waiting for core %u to start... STAT_CONF=0x%x\n", 267 core, stat); 268 mdelay(1000); 269 } 270 271 mips_cpc_unlock_other(); 272 } else { 273 /* Take the core out of reset */ 274 write_gcr_co_reset_release(0); 275 } 276 277 mips_cm_unlock_other(); 278 279 /* The core is now powered up */ 280 bitmap_set(core_power, core, 1); 281 } 282 283 static void remote_vpe_boot(void *dummy) 284 { 285 unsigned core = current_cpu_data.core; 286 struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core]; 287 288 mips_cps_boot_vpes(core_cfg, cpu_vpe_id(¤t_cpu_data)); 289 } 290 291 static void cps_boot_secondary(int cpu, struct task_struct *idle) 292 { 293 unsigned core = cpu_data[cpu].core; 294 unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]); 295 struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core]; 296 struct vpe_boot_config *vpe_cfg = &core_cfg->vpe_config[vpe_id]; 297 unsigned long core_entry; 298 unsigned int remote; 299 int err; 300 301 vpe_cfg->pc = (unsigned long)&smp_bootstrap; 302 vpe_cfg->sp = __KSTK_TOS(idle); 303 vpe_cfg->gp = (unsigned long)task_thread_info(idle); 304 305 atomic_or(1 << cpu_vpe_id(&cpu_data[cpu]), &core_cfg->vpe_mask); 306 307 preempt_disable(); 308 309 if (!test_bit(core, core_power)) { 310 /* Boot a VPE on a powered down core */ 311 boot_core(core, vpe_id); 312 goto out; 313 } 314 315 if (cpu_has_vp) { 316 mips_cm_lock_other(core, vpe_id); 317 core_entry = CKSEG1ADDR((unsigned long)mips_cps_core_entry); 318 write_gcr_co_reset_base(core_entry); 319 mips_cm_unlock_other(); 320 } 321 322 if (core != current_cpu_data.core) { 323 /* Boot a VPE on another powered up core */ 324 for (remote = 0; remote < NR_CPUS; remote++) { 325 if (cpu_data[remote].core != core) 326 continue; 327 if (cpu_online(remote)) 328 break; 329 } 330 if (remote >= NR_CPUS) { 331 pr_crit("No online CPU in core %u to start CPU%d\n", 332 core, cpu); 333 goto out; 334 } 335 336 err = smp_call_function_single(remote, remote_vpe_boot, 337 NULL, 1); 338 if (err) 339 panic("Failed to call remote CPU\n"); 340 goto out; 341 } 342 343 BUG_ON(!cpu_has_mipsmt && !cpu_has_vp); 344 345 /* Boot a VPE on this core */ 346 mips_cps_boot_vpes(core_cfg, vpe_id); 347 out: 348 preempt_enable(); 349 } 350 351 static void cps_init_secondary(void) 352 { 353 /* Disable MT - we only want to run 1 TC per VPE */ 354 if (cpu_has_mipsmt) 355 dmt(); 356 357 if (mips_cm_revision() >= CM_REV_CM3) { 358 unsigned ident = gic_read_local_vp_id(); 359 360 /* 361 * Ensure that our calculation of the VP ID matches up with 362 * what the GIC reports, otherwise we'll have configured 363 * interrupts incorrectly. 364 */ 365 BUG_ON(ident != mips_cm_vp_id(smp_processor_id())); 366 } 367 368 if (cpu_has_veic) 369 clear_c0_status(ST0_IM); 370 else 371 change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 | 372 STATUSF_IP4 | STATUSF_IP5 | 373 STATUSF_IP6 | STATUSF_IP7); 374 } 375 376 static void cps_smp_finish(void) 377 { 378 write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency / HZ)); 379 380 #ifdef CONFIG_MIPS_MT_FPAFF 381 /* If we have an FPU, enroll ourselves in the FPU-full mask */ 382 if (cpu_has_fpu) 383 cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask); 384 #endif /* CONFIG_MIPS_MT_FPAFF */ 385 386 local_irq_enable(); 387 } 388 389 #ifdef CONFIG_HOTPLUG_CPU 390 391 static int cps_cpu_disable(void) 392 { 393 unsigned cpu = smp_processor_id(); 394 struct core_boot_config *core_cfg; 395 396 if (!cpu) 397 return -EBUSY; 398 399 if (!cps_pm_support_state(CPS_PM_POWER_GATED)) 400 return -EINVAL; 401 402 core_cfg = &mips_cps_core_bootcfg[current_cpu_data.core]; 403 atomic_sub(1 << cpu_vpe_id(¤t_cpu_data), &core_cfg->vpe_mask); 404 smp_mb__after_atomic(); 405 set_cpu_online(cpu, false); 406 calculate_cpu_foreign_map(); 407 408 return 0; 409 } 410 411 static DECLARE_COMPLETION(cpu_death_chosen); 412 static unsigned cpu_death_sibling; 413 static enum { 414 CPU_DEATH_HALT, 415 CPU_DEATH_POWER, 416 } cpu_death; 417 418 void play_dead(void) 419 { 420 unsigned int cpu, core, vpe_id; 421 422 local_irq_disable(); 423 idle_task_exit(); 424 cpu = smp_processor_id(); 425 core = cpu_data[cpu].core; 426 cpu_death = CPU_DEATH_POWER; 427 428 pr_debug("CPU%d going offline\n", cpu); 429 430 if (cpu_has_mipsmt || cpu_has_vp) { 431 /* Look for another online VPE within the core */ 432 for_each_online_cpu(cpu_death_sibling) { 433 if (cpu_data[cpu_death_sibling].core != core) 434 continue; 435 436 /* 437 * There is an online VPE within the core. Just halt 438 * this TC and leave the core alone. 439 */ 440 cpu_death = CPU_DEATH_HALT; 441 break; 442 } 443 } 444 445 /* This CPU has chosen its way out */ 446 complete(&cpu_death_chosen); 447 448 if (cpu_death == CPU_DEATH_HALT) { 449 vpe_id = cpu_vpe_id(&cpu_data[cpu]); 450 451 pr_debug("Halting core %d VP%d\n", core, vpe_id); 452 if (cpu_has_mipsmt) { 453 /* Halt this TC */ 454 write_c0_tchalt(TCHALT_H); 455 instruction_hazard(); 456 } else if (cpu_has_vp) { 457 write_cpc_cl_vp_stop(1 << vpe_id); 458 459 /* Ensure that the VP_STOP register is written */ 460 wmb(); 461 } 462 } else { 463 pr_debug("Gating power to core %d\n", core); 464 /* Power down the core */ 465 cps_pm_enter_state(CPS_PM_POWER_GATED); 466 } 467 468 /* This should never be reached */ 469 panic("Failed to offline CPU %u", cpu); 470 } 471 472 static void wait_for_sibling_halt(void *ptr_cpu) 473 { 474 unsigned cpu = (unsigned long)ptr_cpu; 475 unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]); 476 unsigned halted; 477 unsigned long flags; 478 479 do { 480 local_irq_save(flags); 481 settc(vpe_id); 482 halted = read_tc_c0_tchalt(); 483 local_irq_restore(flags); 484 } while (!(halted & TCHALT_H)); 485 } 486 487 static void cps_cpu_die(unsigned int cpu) 488 { 489 unsigned core = cpu_data[cpu].core; 490 unsigned int vpe_id = cpu_vpe_id(&cpu_data[cpu]); 491 unsigned stat; 492 int err; 493 494 /* Wait for the cpu to choose its way out */ 495 if (!wait_for_completion_timeout(&cpu_death_chosen, 496 msecs_to_jiffies(5000))) { 497 pr_err("CPU%u: didn't offline\n", cpu); 498 return; 499 } 500 501 /* 502 * Now wait for the CPU to actually offline. Without doing this that 503 * offlining may race with one or more of: 504 * 505 * - Onlining the CPU again. 506 * - Powering down the core if another VPE within it is offlined. 507 * - A sibling VPE entering a non-coherent state. 508 * 509 * In the non-MT halt case (ie. infinite loop) the CPU is doing nothing 510 * with which we could race, so do nothing. 511 */ 512 if (cpu_death == CPU_DEATH_POWER) { 513 /* 514 * Wait for the core to enter a powered down or clock gated 515 * state, the latter happening when a JTAG probe is connected 516 * in which case the CPC will refuse to power down the core. 517 */ 518 do { 519 mips_cm_lock_other(core, 0); 520 mips_cpc_lock_other(core); 521 stat = read_cpc_co_stat_conf(); 522 stat &= CPC_Cx_STAT_CONF_SEQSTATE_MSK; 523 mips_cpc_unlock_other(); 524 mips_cm_unlock_other(); 525 } while (stat != CPC_Cx_STAT_CONF_SEQSTATE_D0 && 526 stat != CPC_Cx_STAT_CONF_SEQSTATE_D2 && 527 stat != CPC_Cx_STAT_CONF_SEQSTATE_U2); 528 529 /* Indicate the core is powered off */ 530 bitmap_clear(core_power, core, 1); 531 } else if (cpu_has_mipsmt) { 532 /* 533 * Have a CPU with access to the offlined CPUs registers wait 534 * for its TC to halt. 535 */ 536 err = smp_call_function_single(cpu_death_sibling, 537 wait_for_sibling_halt, 538 (void *)(unsigned long)cpu, 1); 539 if (err) 540 panic("Failed to call remote sibling CPU\n"); 541 } else if (cpu_has_vp) { 542 do { 543 mips_cm_lock_other(core, vpe_id); 544 stat = read_cpc_co_vp_running(); 545 mips_cm_unlock_other(); 546 } while (stat & (1 << vpe_id)); 547 } 548 } 549 550 #endif /* CONFIG_HOTPLUG_CPU */ 551 552 static struct plat_smp_ops cps_smp_ops = { 553 .smp_setup = cps_smp_setup, 554 .prepare_cpus = cps_prepare_cpus, 555 .boot_secondary = cps_boot_secondary, 556 .init_secondary = cps_init_secondary, 557 .smp_finish = cps_smp_finish, 558 .send_ipi_single = mips_smp_send_ipi_single, 559 .send_ipi_mask = mips_smp_send_ipi_mask, 560 #ifdef CONFIG_HOTPLUG_CPU 561 .cpu_disable = cps_cpu_disable, 562 .cpu_die = cps_cpu_die, 563 #endif 564 }; 565 566 bool mips_cps_smp_in_use(void) 567 { 568 extern struct plat_smp_ops *mp_ops; 569 return mp_ops == &cps_smp_ops; 570 } 571 572 int register_cps_smp_ops(void) 573 { 574 if (!mips_cm_present()) { 575 pr_warn("MIPS CPS SMP unable to proceed without a CM\n"); 576 return -ENODEV; 577 } 578 579 /* check we have a GIC - we need one for IPIs */ 580 if (!(read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX_MSK)) { 581 pr_warn("MIPS CPS SMP unable to proceed without a GIC\n"); 582 return -ENODEV; 583 } 584 585 register_smp_ops(&cps_smp_ops); 586 return 0; 587 } 588