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.h> 15 #include <linux/slab.h> 16 #include <linux/smp.h> 17 #include <linux/types.h> 18 19 #include <asm/bcache.h> 20 #include <asm/mips-cm.h> 21 #include <asm/mips-cpc.h> 22 #include <asm/mips_mt.h> 23 #include <asm/mipsregs.h> 24 #include <asm/pm-cps.h> 25 #include <asm/r4kcache.h> 26 #include <asm/smp-cps.h> 27 #include <asm/time.h> 28 #include <asm/uasm.h> 29 30 static bool threads_disabled; 31 static DECLARE_BITMAP(core_power, NR_CPUS); 32 33 struct core_boot_config *mips_cps_core_bootcfg; 34 35 static int __init setup_nothreads(char *s) 36 { 37 threads_disabled = true; 38 return 0; 39 } 40 early_param("nothreads", setup_nothreads); 41 42 static unsigned core_vpe_count(unsigned core) 43 { 44 unsigned cfg; 45 46 if (threads_disabled) 47 return 1; 48 49 if ((!config_enabled(CONFIG_MIPS_MT_SMP) || !cpu_has_mipsmt) 50 && (!config_enabled(CONFIG_CPU_MIPSR6) || !cpu_has_vp)) 51 return 1; 52 53 mips_cm_lock_other(core, 0); 54 cfg = read_gcr_co_config() & CM_GCR_Cx_CONFIG_PVPE_MSK; 55 mips_cm_unlock_other(); 56 return (cfg >> CM_GCR_Cx_CONFIG_PVPE_SHF) + 1; 57 } 58 59 static void __init cps_smp_setup(void) 60 { 61 unsigned int ncores, nvpes, core_vpes; 62 unsigned long core_entry; 63 int c, v; 64 65 /* Detect & record VPE topology */ 66 ncores = mips_cm_numcores(); 67 pr_info("%s topology ", cpu_has_mips_r6 ? "VP" : "VPE"); 68 for (c = nvpes = 0; c < ncores; c++) { 69 core_vpes = core_vpe_count(c); 70 pr_cont("%c%u", c ? ',' : '{', core_vpes); 71 72 /* Use the number of VPEs in core 0 for smp_num_siblings */ 73 if (!c) 74 smp_num_siblings = core_vpes; 75 76 for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) { 77 cpu_data[nvpes + v].core = c; 78 #if defined(CONFIG_MIPS_MT_SMP) || defined(CONFIG_CPU_MIPSR6) 79 cpu_data[nvpes + v].vpe_id = v; 80 #endif 81 } 82 83 nvpes += core_vpes; 84 } 85 pr_cont("} total %u\n", nvpes); 86 87 /* Indicate present CPUs (CPU being synonymous with VPE) */ 88 for (v = 0; v < min_t(unsigned, nvpes, NR_CPUS); v++) { 89 set_cpu_possible(v, true); 90 set_cpu_present(v, true); 91 __cpu_number_map[v] = v; 92 __cpu_logical_map[v] = v; 93 } 94 95 /* Set a coherent default CCA (CWB) */ 96 change_c0_config(CONF_CM_CMASK, 0x5); 97 98 /* Core 0 is powered up (we're running on it) */ 99 bitmap_set(core_power, 0, 1); 100 101 /* Initialise core 0 */ 102 mips_cps_core_init(); 103 104 /* Make core 0 coherent with everything */ 105 write_gcr_cl_coherence(0xff); 106 107 if (mips_cm_revision() >= CM_REV_CM3) { 108 core_entry = CKSEG1ADDR((unsigned long)mips_cps_core_entry); 109 write_gcr_bev_base(core_entry); 110 } 111 112 #ifdef CONFIG_MIPS_MT_FPAFF 113 /* If we have an FPU, enroll ourselves in the FPU-full mask */ 114 if (cpu_has_fpu) 115 cpumask_set_cpu(0, &mt_fpu_cpumask); 116 #endif /* CONFIG_MIPS_MT_FPAFF */ 117 } 118 119 static void __init cps_prepare_cpus(unsigned int max_cpus) 120 { 121 unsigned ncores, core_vpes, c, cca; 122 bool cca_unsuitable; 123 u32 *entry_code; 124 125 mips_mt_set_cpuoptions(); 126 127 /* Detect whether the CCA is unsuited to multi-core SMP */ 128 cca = read_c0_config() & CONF_CM_CMASK; 129 switch (cca) { 130 case 0x4: /* CWBE */ 131 case 0x5: /* CWB */ 132 /* The CCA is coherent, multi-core is fine */ 133 cca_unsuitable = false; 134 break; 135 136 default: 137 /* CCA is not coherent, multi-core is not usable */ 138 cca_unsuitable = true; 139 } 140 141 /* Warn the user if the CCA prevents multi-core */ 142 ncores = mips_cm_numcores(); 143 if (cca_unsuitable && ncores > 1) { 144 pr_warn("Using only one core due to unsuitable CCA 0x%x\n", 145 cca); 146 147 for_each_present_cpu(c) { 148 if (cpu_data[c].core) 149 set_cpu_present(c, false); 150 } 151 } 152 153 /* 154 * Patch the start of mips_cps_core_entry to provide: 155 * 156 * s0 = kseg0 CCA 157 */ 158 entry_code = (u32 *)&mips_cps_core_entry; 159 uasm_i_addiu(&entry_code, 16, 0, cca); 160 blast_dcache_range((unsigned long)&mips_cps_core_entry, 161 (unsigned long)entry_code); 162 bc_wback_inv((unsigned long)&mips_cps_core_entry, 163 (void *)entry_code - (void *)&mips_cps_core_entry); 164 __sync(); 165 166 /* Allocate core boot configuration structs */ 167 mips_cps_core_bootcfg = kcalloc(ncores, sizeof(*mips_cps_core_bootcfg), 168 GFP_KERNEL); 169 if (!mips_cps_core_bootcfg) { 170 pr_err("Failed to allocate boot config for %u cores\n", ncores); 171 goto err_out; 172 } 173 174 /* Allocate VPE boot configuration structs */ 175 for (c = 0; c < ncores; c++) { 176 core_vpes = core_vpe_count(c); 177 mips_cps_core_bootcfg[c].vpe_config = kcalloc(core_vpes, 178 sizeof(*mips_cps_core_bootcfg[c].vpe_config), 179 GFP_KERNEL); 180 if (!mips_cps_core_bootcfg[c].vpe_config) { 181 pr_err("Failed to allocate %u VPE boot configs\n", 182 core_vpes); 183 goto err_out; 184 } 185 } 186 187 /* Mark this CPU as booted */ 188 atomic_set(&mips_cps_core_bootcfg[current_cpu_data.core].vpe_mask, 189 1 << cpu_vpe_id(¤t_cpu_data)); 190 191 return; 192 err_out: 193 /* Clean up allocations */ 194 if (mips_cps_core_bootcfg) { 195 for (c = 0; c < ncores; c++) 196 kfree(mips_cps_core_bootcfg[c].vpe_config); 197 kfree(mips_cps_core_bootcfg); 198 mips_cps_core_bootcfg = NULL; 199 } 200 201 /* Effectively disable SMP by declaring CPUs not present */ 202 for_each_possible_cpu(c) { 203 if (c == 0) 204 continue; 205 set_cpu_present(c, false); 206 } 207 } 208 209 static void boot_core(unsigned core) 210 { 211 u32 access, stat, seq_state; 212 unsigned timeout; 213 214 /* Select the appropriate core */ 215 mips_cm_lock_other(core, 0); 216 217 /* Set its reset vector */ 218 write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry)); 219 220 /* Ensure its coherency is disabled */ 221 write_gcr_co_coherence(0); 222 223 /* Start it with the legacy memory map and exception base */ 224 write_gcr_co_reset_ext_base(CM_GCR_RESET_EXT_BASE_UEB); 225 226 /* Ensure the core can access the GCRs */ 227 access = read_gcr_access(); 228 access |= 1 << (CM_GCR_ACCESS_ACCESSEN_SHF + core); 229 write_gcr_access(access); 230 231 if (mips_cpc_present()) { 232 /* Reset the core */ 233 mips_cpc_lock_other(core); 234 235 if (mips_cm_revision() >= CM_REV_CM3) { 236 /* Run VP0 following the reset */ 237 write_cpc_co_vp_run(0x1); 238 239 /* 240 * Ensure that the VP_RUN register is written before the 241 * core leaves reset. 242 */ 243 wmb(); 244 } 245 246 write_cpc_co_cmd(CPC_Cx_CMD_RESET); 247 248 timeout = 100; 249 while (true) { 250 stat = read_cpc_co_stat_conf(); 251 seq_state = stat & CPC_Cx_STAT_CONF_SEQSTATE_MSK; 252 253 /* U6 == coherent execution, ie. the core is up */ 254 if (seq_state == CPC_Cx_STAT_CONF_SEQSTATE_U6) 255 break; 256 257 /* Delay a little while before we start warning */ 258 if (timeout) { 259 timeout--; 260 mdelay(10); 261 continue; 262 } 263 264 pr_warn("Waiting for core %u to start... STAT_CONF=0x%x\n", 265 core, stat); 266 mdelay(1000); 267 } 268 269 mips_cpc_unlock_other(); 270 } else { 271 /* Take the core out of reset */ 272 write_gcr_co_reset_release(0); 273 } 274 275 mips_cm_unlock_other(); 276 277 /* The core is now powered up */ 278 bitmap_set(core_power, core, 1); 279 } 280 281 static void remote_vpe_boot(void *dummy) 282 { 283 unsigned core = current_cpu_data.core; 284 struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core]; 285 286 mips_cps_boot_vpes(core_cfg, cpu_vpe_id(¤t_cpu_data)); 287 } 288 289 static void cps_boot_secondary(int cpu, struct task_struct *idle) 290 { 291 unsigned core = cpu_data[cpu].core; 292 unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]); 293 struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core]; 294 struct vpe_boot_config *vpe_cfg = &core_cfg->vpe_config[vpe_id]; 295 unsigned long core_entry; 296 unsigned int remote; 297 int err; 298 299 vpe_cfg->pc = (unsigned long)&smp_bootstrap; 300 vpe_cfg->sp = __KSTK_TOS(idle); 301 vpe_cfg->gp = (unsigned long)task_thread_info(idle); 302 303 atomic_or(1 << cpu_vpe_id(&cpu_data[cpu]), &core_cfg->vpe_mask); 304 305 preempt_disable(); 306 307 if (!test_bit(core, core_power)) { 308 /* Boot a VPE on a powered down core */ 309 boot_core(core); 310 goto out; 311 } 312 313 if (cpu_has_vp) { 314 mips_cm_lock_other(core, vpe_id); 315 core_entry = CKSEG1ADDR((unsigned long)mips_cps_core_entry); 316 write_gcr_co_reset_base(core_entry); 317 mips_cm_unlock_other(); 318 } 319 320 if (core != current_cpu_data.core) { 321 /* Boot a VPE on another powered up core */ 322 for (remote = 0; remote < NR_CPUS; remote++) { 323 if (cpu_data[remote].core != core) 324 continue; 325 if (cpu_online(remote)) 326 break; 327 } 328 BUG_ON(remote >= NR_CPUS); 329 330 err = smp_call_function_single(remote, remote_vpe_boot, 331 NULL, 1); 332 if (err) 333 panic("Failed to call remote CPU\n"); 334 goto out; 335 } 336 337 BUG_ON(!cpu_has_mipsmt && !cpu_has_vp); 338 339 /* Boot a VPE on this core */ 340 mips_cps_boot_vpes(core_cfg, vpe_id); 341 out: 342 preempt_enable(); 343 } 344 345 static void cps_init_secondary(void) 346 { 347 /* Disable MT - we only want to run 1 TC per VPE */ 348 if (cpu_has_mipsmt) 349 dmt(); 350 351 if (mips_cm_revision() >= CM_REV_CM3) { 352 unsigned ident = gic_read_local_vp_id(); 353 354 /* 355 * Ensure that our calculation of the VP ID matches up with 356 * what the GIC reports, otherwise we'll have configured 357 * interrupts incorrectly. 358 */ 359 BUG_ON(ident != mips_cm_vp_id(smp_processor_id())); 360 } 361 362 if (cpu_has_veic) 363 clear_c0_status(ST0_IM); 364 else 365 change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 | 366 STATUSF_IP4 | STATUSF_IP5 | 367 STATUSF_IP6 | STATUSF_IP7); 368 } 369 370 static void cps_smp_finish(void) 371 { 372 write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency / HZ)); 373 374 #ifdef CONFIG_MIPS_MT_FPAFF 375 /* If we have an FPU, enroll ourselves in the FPU-full mask */ 376 if (cpu_has_fpu) 377 cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask); 378 #endif /* CONFIG_MIPS_MT_FPAFF */ 379 380 local_irq_enable(); 381 } 382 383 #ifdef CONFIG_HOTPLUG_CPU 384 385 static int cps_cpu_disable(void) 386 { 387 unsigned cpu = smp_processor_id(); 388 struct core_boot_config *core_cfg; 389 390 if (!cpu) 391 return -EBUSY; 392 393 if (!cps_pm_support_state(CPS_PM_POWER_GATED)) 394 return -EINVAL; 395 396 core_cfg = &mips_cps_core_bootcfg[current_cpu_data.core]; 397 atomic_sub(1 << cpu_vpe_id(¤t_cpu_data), &core_cfg->vpe_mask); 398 smp_mb__after_atomic(); 399 set_cpu_online(cpu, false); 400 cpumask_clear_cpu(cpu, &cpu_callin_map); 401 402 return 0; 403 } 404 405 static DECLARE_COMPLETION(cpu_death_chosen); 406 static unsigned cpu_death_sibling; 407 static enum { 408 CPU_DEATH_HALT, 409 CPU_DEATH_POWER, 410 } cpu_death; 411 412 void play_dead(void) 413 { 414 unsigned cpu, core; 415 416 local_irq_disable(); 417 idle_task_exit(); 418 cpu = smp_processor_id(); 419 cpu_death = CPU_DEATH_POWER; 420 421 if (cpu_has_mipsmt) { 422 core = cpu_data[cpu].core; 423 424 /* Look for another online VPE within the core */ 425 for_each_online_cpu(cpu_death_sibling) { 426 if (cpu_data[cpu_death_sibling].core != core) 427 continue; 428 429 /* 430 * There is an online VPE within the core. Just halt 431 * this TC and leave the core alone. 432 */ 433 cpu_death = CPU_DEATH_HALT; 434 break; 435 } 436 } 437 438 /* This CPU has chosen its way out */ 439 complete(&cpu_death_chosen); 440 441 if (cpu_death == CPU_DEATH_HALT) { 442 /* Halt this TC */ 443 write_c0_tchalt(TCHALT_H); 444 instruction_hazard(); 445 } else { 446 /* Power down the core */ 447 cps_pm_enter_state(CPS_PM_POWER_GATED); 448 } 449 450 /* This should never be reached */ 451 panic("Failed to offline CPU %u", cpu); 452 } 453 454 static void wait_for_sibling_halt(void *ptr_cpu) 455 { 456 unsigned cpu = (unsigned long)ptr_cpu; 457 unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]); 458 unsigned halted; 459 unsigned long flags; 460 461 do { 462 local_irq_save(flags); 463 settc(vpe_id); 464 halted = read_tc_c0_tchalt(); 465 local_irq_restore(flags); 466 } while (!(halted & TCHALT_H)); 467 } 468 469 static void cps_cpu_die(unsigned int cpu) 470 { 471 unsigned core = cpu_data[cpu].core; 472 unsigned stat; 473 int err; 474 475 /* Wait for the cpu to choose its way out */ 476 if (!wait_for_completion_timeout(&cpu_death_chosen, 477 msecs_to_jiffies(5000))) { 478 pr_err("CPU%u: didn't offline\n", cpu); 479 return; 480 } 481 482 /* 483 * Now wait for the CPU to actually offline. Without doing this that 484 * offlining may race with one or more of: 485 * 486 * - Onlining the CPU again. 487 * - Powering down the core if another VPE within it is offlined. 488 * - A sibling VPE entering a non-coherent state. 489 * 490 * In the non-MT halt case (ie. infinite loop) the CPU is doing nothing 491 * with which we could race, so do nothing. 492 */ 493 if (cpu_death == CPU_DEATH_POWER) { 494 /* 495 * Wait for the core to enter a powered down or clock gated 496 * state, the latter happening when a JTAG probe is connected 497 * in which case the CPC will refuse to power down the core. 498 */ 499 do { 500 mips_cpc_lock_other(core); 501 stat = read_cpc_co_stat_conf(); 502 stat &= CPC_Cx_STAT_CONF_SEQSTATE_MSK; 503 mips_cpc_unlock_other(); 504 } while (stat != CPC_Cx_STAT_CONF_SEQSTATE_D0 && 505 stat != CPC_Cx_STAT_CONF_SEQSTATE_D2 && 506 stat != CPC_Cx_STAT_CONF_SEQSTATE_U2); 507 508 /* Indicate the core is powered off */ 509 bitmap_clear(core_power, core, 1); 510 } else if (cpu_has_mipsmt) { 511 /* 512 * Have a CPU with access to the offlined CPUs registers wait 513 * for its TC to halt. 514 */ 515 err = smp_call_function_single(cpu_death_sibling, 516 wait_for_sibling_halt, 517 (void *)(unsigned long)cpu, 1); 518 if (err) 519 panic("Failed to call remote sibling CPU\n"); 520 } 521 } 522 523 #endif /* CONFIG_HOTPLUG_CPU */ 524 525 static struct plat_smp_ops cps_smp_ops = { 526 .smp_setup = cps_smp_setup, 527 .prepare_cpus = cps_prepare_cpus, 528 .boot_secondary = cps_boot_secondary, 529 .init_secondary = cps_init_secondary, 530 .smp_finish = cps_smp_finish, 531 .send_ipi_single = mips_smp_send_ipi_single, 532 .send_ipi_mask = mips_smp_send_ipi_mask, 533 #ifdef CONFIG_HOTPLUG_CPU 534 .cpu_disable = cps_cpu_disable, 535 .cpu_die = cps_cpu_die, 536 #endif 537 }; 538 539 bool mips_cps_smp_in_use(void) 540 { 541 extern struct plat_smp_ops *mp_ops; 542 return mp_ops == &cps_smp_ops; 543 } 544 545 int register_cps_smp_ops(void) 546 { 547 if (!mips_cm_present()) { 548 pr_warn("MIPS CPS SMP unable to proceed without a CM\n"); 549 return -ENODEV; 550 } 551 552 /* check we have a GIC - we need one for IPIs */ 553 if (!(read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX_MSK)) { 554 pr_warn("MIPS CPS SMP unable to proceed without a GIC\n"); 555 return -ENODEV; 556 } 557 558 register_smp_ops(&cps_smp_ops); 559 return 0; 560 } 561