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
33enum label_id {
34 label_not_nmi = 1,
35};
36
37UASM_L_LA(_not_nmi)
38
39static DECLARE_BITMAP(core_power, NR_CPUS);
40static uint32_t core_entry_reg;
41static phys_addr_t cps_vec_pa;
42
43struct core_boot_config *mips_cps_core_bootcfg;
44
45static unsigned __init core_vpe_count(unsigned int cluster, unsigned core)
46{
47 return min(smp_max_threads, mips_cps_numvps(cluster, core));
48}
49
50static 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
97static 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
121static 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(addr: 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
141static 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
213static 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(cpu: c, present: 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;
285err_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(cpu: c, present: false);
299 }
300}
301
302static 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 set_gcr_access(1 << core);
321
322 if (mips_cpc_present()) {
323 /* Reset the core */
324 mips_cpc_lock_other(core);
325
326 if (mips_cm_revision() >= CM_REV_CM3) {
327 /* Run only the requested VP following the reset */
328 write_cpc_co_vp_stop(0xf);
329 write_cpc_co_vp_run(1 << vpe_id);
330
331 /*
332 * Ensure that the VP_RUN register is written before the
333 * core leaves reset.
334 */
335 wmb();
336 }
337
338 write_cpc_co_cmd(CPC_Cx_CMD_RESET);
339
340 timeout = 100;
341 while (true) {
342 stat = read_cpc_co_stat_conf();
343 seq_state = stat & CPC_Cx_STAT_CONF_SEQSTATE;
344 seq_state >>= __ffs(CPC_Cx_STAT_CONF_SEQSTATE);
345
346 /* U6 == coherent execution, ie. the core is up */
347 if (seq_state == CPC_Cx_STAT_CONF_SEQSTATE_U6)
348 break;
349
350 /* Delay a little while before we start warning */
351 if (timeout) {
352 timeout--;
353 mdelay(10);
354 continue;
355 }
356
357 pr_warn("Waiting for core %u to start... STAT_CONF=0x%x\n",
358 core, stat);
359 mdelay(1000);
360 }
361
362 mips_cpc_unlock_other();
363 } else {
364 /* Take the core out of reset */
365 write_gcr_co_reset_release(0);
366 }
367
368 mips_cm_unlock_other();
369
370 /* The core is now powered up */
371 bitmap_set(core_power, core, 1);
372}
373
374static void remote_vpe_boot(void *dummy)
375{
376 unsigned core = cpu_core(&current_cpu_data);
377 struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
378
379 mips_cps_boot_vpes(core_cfg, cpu_vpe_id(&current_cpu_data));
380}
381
382static int cps_boot_secondary(int cpu, struct task_struct *idle)
383{
384 unsigned core = cpu_core(&cpu_data[cpu]);
385 unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
386 struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
387 struct vpe_boot_config *vpe_cfg = &core_cfg->vpe_config[vpe_id];
388 unsigned int remote;
389 int err;
390
391 /* We don't yet support booting CPUs in other clusters */
392 if (cpu_cluster(&cpu_data[cpu]) != cpu_cluster(&raw_current_cpu_data))
393 return -ENOSYS;
394
395 vpe_cfg->pc = (unsigned long)&smp_bootstrap;
396 vpe_cfg->sp = __KSTK_TOS(idle);
397 vpe_cfg->gp = (unsigned long)task_thread_info(idle);
398
399 atomic_or(1 << cpu_vpe_id(&cpu_data[cpu]), &core_cfg->vpe_mask);
400
401 preempt_disable();
402
403 if (!test_bit(core, core_power)) {
404 /* Boot a VPE on a powered down core */
405 boot_core(core, vpe_id);
406 goto out;
407 }
408
409 if (cpu_has_vp) {
410 mips_cm_lock_other(0, core, vpe_id, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
411 write_gcr_co_reset_base(core_entry_reg);
412 mips_cm_unlock_other();
413 }
414
415 if (!cpus_are_siblings(cpu, smp_processor_id())) {
416 /* Boot a VPE on another powered up core */
417 for (remote = 0; remote < NR_CPUS; remote++) {
418 if (!cpus_are_siblings(cpu, remote))
419 continue;
420 if (cpu_online(cpu: remote))
421 break;
422 }
423 if (remote >= NR_CPUS) {
424 pr_crit("No online CPU in core %u to start CPU%d\n",
425 core, cpu);
426 goto out;
427 }
428
429 err = smp_call_function_single(cpuid: remote, func: remote_vpe_boot,
430 NULL, wait: 1);
431 if (err)
432 panic(fmt: "Failed to call remote CPU\n");
433 goto out;
434 }
435
436 BUG_ON(!cpu_has_mipsmt && !cpu_has_vp);
437
438 /* Boot a VPE on this core */
439 mips_cps_boot_vpes(core_cfg, vpe_id);
440out:
441 preempt_enable();
442 return 0;
443}
444
445static void cps_init_secondary(void)
446{
447 int core = cpu_core(&current_cpu_data);
448
449 /* Disable MT - we only want to run 1 TC per VPE */
450 if (cpu_has_mipsmt)
451 dmt();
452
453 if (mips_cm_revision() >= CM_REV_CM3) {
454 unsigned int ident = read_gic_vl_ident();
455
456 /*
457 * Ensure that our calculation of the VP ID matches up with
458 * what the GIC reports, otherwise we'll have configured
459 * interrupts incorrectly.
460 */
461 BUG_ON(ident != mips_cm_vp_id(smp_processor_id()));
462 }
463
464 if (core > 0 && !read_gcr_cl_coherence())
465 pr_warn("Core %u is not in coherent domain\n", core);
466
467 if (cpu_has_veic)
468 clear_c0_status(ST0_IM);
469 else
470 change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 |
471 STATUSF_IP4 | STATUSF_IP5 |
472 STATUSF_IP6 | STATUSF_IP7);
473}
474
475static void cps_smp_finish(void)
476{
477 write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency / HZ));
478
479#ifdef CONFIG_MIPS_MT_FPAFF
480 /* If we have an FPU, enroll ourselves in the FPU-full mask */
481 if (cpu_has_fpu)
482 cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask);
483#endif /* CONFIG_MIPS_MT_FPAFF */
484
485 local_irq_enable();
486}
487
488#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_KEXEC_CORE)
489
490enum cpu_death {
491 CPU_DEATH_HALT,
492 CPU_DEATH_POWER,
493};
494
495static void cps_shutdown_this_cpu(enum cpu_death death)
496{
497 unsigned int cpu, core, vpe_id;
498
499 cpu = smp_processor_id();
500 core = cpu_core(&cpu_data[cpu]);
501
502 if (death == CPU_DEATH_HALT) {
503 vpe_id = cpu_vpe_id(&cpu_data[cpu]);
504
505 pr_debug("Halting core %d VP%d\n", core, vpe_id);
506 if (cpu_has_mipsmt) {
507 /* Halt this TC */
508 write_c0_tchalt(TCHALT_H);
509 instruction_hazard();
510 } else if (cpu_has_vp) {
511 write_cpc_cl_vp_stop(1 << vpe_id);
512
513 /* Ensure that the VP_STOP register is written */
514 wmb();
515 }
516 } else {
517 if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
518 pr_debug("Gating power to core %d\n", core);
519 /* Power down the core */
520 cps_pm_enter_state(CPS_PM_POWER_GATED);
521 }
522 }
523}
524
525#ifdef CONFIG_KEXEC_CORE
526
527static void cps_kexec_nonboot_cpu(void)
528{
529 if (cpu_has_mipsmt || cpu_has_vp)
530 cps_shutdown_this_cpu(death: CPU_DEATH_HALT);
531 else
532 cps_shutdown_this_cpu(death: CPU_DEATH_POWER);
533}
534
535#endif /* CONFIG_KEXEC_CORE */
536
537#endif /* CONFIG_HOTPLUG_CPU || CONFIG_KEXEC_CORE */
538
539#ifdef CONFIG_HOTPLUG_CPU
540
541static int cps_cpu_disable(void)
542{
543 unsigned cpu = smp_processor_id();
544 struct core_boot_config *core_cfg;
545
546 if (!cps_pm_support_state(CPS_PM_POWER_GATED))
547 return -EINVAL;
548
549 core_cfg = &mips_cps_core_bootcfg[cpu_core(&current_cpu_data)];
550 atomic_sub(1 << cpu_vpe_id(&current_cpu_data), &core_cfg->vpe_mask);
551 smp_mb__after_atomic();
552 set_cpu_online(cpu, online: false);
553 calculate_cpu_foreign_map();
554 irq_migrate_all_off_this_cpu();
555
556 return 0;
557}
558
559static unsigned cpu_death_sibling;
560static enum cpu_death cpu_death;
561
562void play_dead(void)
563{
564 unsigned int cpu;
565
566 local_irq_disable();
567 idle_task_exit();
568 cpu = smp_processor_id();
569 cpu_death = CPU_DEATH_POWER;
570
571 pr_debug("CPU%d going offline\n", cpu);
572
573 if (cpu_has_mipsmt || cpu_has_vp) {
574 /* Look for another online VPE within the core */
575 for_each_online_cpu(cpu_death_sibling) {
576 if (!cpus_are_siblings(cpu, cpu_death_sibling))
577 continue;
578
579 /*
580 * There is an online VPE within the core. Just halt
581 * this TC and leave the core alone.
582 */
583 cpu_death = CPU_DEATH_HALT;
584 break;
585 }
586 }
587
588 cpuhp_ap_report_dead();
589
590 cps_shutdown_this_cpu(death: cpu_death);
591
592 /* This should never be reached */
593 panic(fmt: "Failed to offline CPU %u", cpu);
594}
595
596static void wait_for_sibling_halt(void *ptr_cpu)
597{
598 unsigned cpu = (unsigned long)ptr_cpu;
599 unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
600 unsigned halted;
601 unsigned long flags;
602
603 do {
604 local_irq_save(flags);
605 settc(vpe_id);
606 halted = read_tc_c0_tchalt();
607 local_irq_restore(flags);
608 } while (!(halted & TCHALT_H));
609}
610
611static void cps_cpu_die(unsigned int cpu) { }
612
613static void cps_cleanup_dead_cpu(unsigned cpu)
614{
615 unsigned core = cpu_core(&cpu_data[cpu]);
616 unsigned int vpe_id = cpu_vpe_id(&cpu_data[cpu]);
617 ktime_t fail_time;
618 unsigned stat;
619 int err;
620
621 /*
622 * Now wait for the CPU to actually offline. Without doing this that
623 * offlining may race with one or more of:
624 *
625 * - Onlining the CPU again.
626 * - Powering down the core if another VPE within it is offlined.
627 * - A sibling VPE entering a non-coherent state.
628 *
629 * In the non-MT halt case (ie. infinite loop) the CPU is doing nothing
630 * with which we could race, so do nothing.
631 */
632 if (cpu_death == CPU_DEATH_POWER) {
633 /*
634 * Wait for the core to enter a powered down or clock gated
635 * state, the latter happening when a JTAG probe is connected
636 * in which case the CPC will refuse to power down the core.
637 */
638 fail_time = ktime_add_ms(kt: ktime_get(), msec: 2000);
639 do {
640 mips_cm_lock_other(0, core, 0, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
641 mips_cpc_lock_other(core);
642 stat = read_cpc_co_stat_conf();
643 stat &= CPC_Cx_STAT_CONF_SEQSTATE;
644 stat >>= __ffs(CPC_Cx_STAT_CONF_SEQSTATE);
645 mips_cpc_unlock_other();
646 mips_cm_unlock_other();
647
648 if (stat == CPC_Cx_STAT_CONF_SEQSTATE_D0 ||
649 stat == CPC_Cx_STAT_CONF_SEQSTATE_D2 ||
650 stat == CPC_Cx_STAT_CONF_SEQSTATE_U2)
651 break;
652
653 /*
654 * The core ought to have powered down, but didn't &
655 * now we don't really know what state it's in. It's
656 * likely that its _pwr_up pin has been wired to logic
657 * 1 & it powered back up as soon as we powered it
658 * down...
659 *
660 * The best we can do is warn the user & continue in
661 * the hope that the core is doing nothing harmful &
662 * might behave properly if we online it later.
663 */
664 if (WARN(ktime_after(ktime_get(), fail_time),
665 "CPU%u hasn't powered down, seq. state %u\n",
666 cpu, stat))
667 break;
668 } while (1);
669
670 /* Indicate the core is powered off */
671 bitmap_clear(core_power, core, 1);
672 } else if (cpu_has_mipsmt) {
673 /*
674 * Have a CPU with access to the offlined CPUs registers wait
675 * for its TC to halt.
676 */
677 err = smp_call_function_single(cpuid: cpu_death_sibling,
678 func: wait_for_sibling_halt,
679 info: (void *)(unsigned long)cpu, wait: 1);
680 if (err)
681 panic(fmt: "Failed to call remote sibling CPU\n");
682 } else if (cpu_has_vp) {
683 do {
684 mips_cm_lock_other(0, core, vpe_id, CM_GCR_Cx_OTHER_BLOCK_LOCAL);
685 stat = read_cpc_co_vp_running();
686 mips_cm_unlock_other();
687 } while (stat & (1 << vpe_id));
688 }
689}
690
691#endif /* CONFIG_HOTPLUG_CPU */
692
693static const struct plat_smp_ops cps_smp_ops = {
694 .smp_setup = cps_smp_setup,
695 .prepare_cpus = cps_prepare_cpus,
696 .boot_secondary = cps_boot_secondary,
697 .init_secondary = cps_init_secondary,
698 .smp_finish = cps_smp_finish,
699 .send_ipi_single = mips_smp_send_ipi_single,
700 .send_ipi_mask = mips_smp_send_ipi_mask,
701#ifdef CONFIG_HOTPLUG_CPU
702 .cpu_disable = cps_cpu_disable,
703 .cpu_die = cps_cpu_die,
704 .cleanup_dead_cpu = cps_cleanup_dead_cpu,
705#endif
706#ifdef CONFIG_KEXEC_CORE
707 .kexec_nonboot_cpu = cps_kexec_nonboot_cpu,
708#endif
709};
710
711bool mips_cps_smp_in_use(void)
712{
713 extern const struct plat_smp_ops *mp_ops;
714 return mp_ops == &cps_smp_ops;
715}
716
717int register_cps_smp_ops(void)
718{
719 if (!mips_cm_present()) {
720 pr_warn("MIPS CPS SMP unable to proceed without a CM\n");
721 return -ENODEV;
722 }
723
724 /* check we have a GIC - we need one for IPIs */
725 if (!(read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX)) {
726 pr_warn("MIPS CPS SMP unable to proceed without a GIC\n");
727 return -ENODEV;
728 }
729
730 register_smp_ops(&cps_smp_ops);
731 return 0;
732}
733

source code of linux/arch/mips/kernel/smp-cps.c