1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PowerNV cpuidle code
4  *
5  * Copyright 2015 IBM Corp.
6  */
7 
8 #include <linux/types.h>
9 #include <linux/mm.h>
10 #include <linux/slab.h>
11 #include <linux/of.h>
12 #include <linux/device.h>
13 #include <linux/cpu.h>
14 
15 #include <asm/firmware.h>
16 #include <asm/interrupt.h>
17 #include <asm/machdep.h>
18 #include <asm/opal.h>
19 #include <asm/cputhreads.h>
20 #include <asm/cpuidle.h>
21 #include <asm/code-patching.h>
22 #include <asm/smp.h>
23 #include <asm/runlatch.h>
24 #include <asm/dbell.h>
25 
26 #include "powernv.h"
27 #include "subcore.h"
28 
29 /* Power ISA 3.0 allows for stop states 0x0 - 0xF */
30 #define MAX_STOP_STATE	0xF
31 
32 #define P9_STOP_SPR_MSR 2000
33 #define P9_STOP_SPR_PSSCR      855
34 
35 static u32 supported_cpuidle_states;
36 struct pnv_idle_states_t *pnv_idle_states;
37 int nr_pnv_idle_states;
38 
39 /*
40  * The default stop state that will be used by ppc_md.power_save
41  * function on platforms that support stop instruction.
42  */
43 static u64 pnv_default_stop_val;
44 static u64 pnv_default_stop_mask;
45 static bool default_stop_found;
46 
47 /*
48  * First stop state levels when SPR and TB loss can occur.
49  */
50 static u64 pnv_first_tb_loss_level = MAX_STOP_STATE + 1;
51 static u64 deep_spr_loss_state = MAX_STOP_STATE + 1;
52 
53 /*
54  * psscr value and mask of the deepest stop idle state.
55  * Used when a cpu is offlined.
56  */
57 static u64 pnv_deepest_stop_psscr_val;
58 static u64 pnv_deepest_stop_psscr_mask;
59 static u64 pnv_deepest_stop_flag;
60 static bool deepest_stop_found;
61 
62 static unsigned long power7_offline_type;
63 
64 static int __init pnv_save_sprs_for_deep_states(void)
65 {
66 	int cpu;
67 	int rc;
68 
69 	/*
70 	 * hid0, hid1, hid4, hid5, hmeer and lpcr values are symmetric across
71 	 * all cpus at boot. Get these reg values of current cpu and use the
72 	 * same across all cpus.
73 	 */
74 	uint64_t lpcr_val	= mfspr(SPRN_LPCR);
75 	uint64_t hid0_val	= mfspr(SPRN_HID0);
76 	uint64_t hmeer_val	= mfspr(SPRN_HMEER);
77 	uint64_t msr_val = MSR_IDLE;
78 	uint64_t psscr_val = pnv_deepest_stop_psscr_val;
79 
80 	for_each_present_cpu(cpu) {
81 		uint64_t pir = get_hard_smp_processor_id(cpu);
82 		uint64_t hsprg0_val = (uint64_t)paca_ptrs[cpu];
83 
84 		rc = opal_slw_set_reg(pir, SPRN_HSPRG0, hsprg0_val);
85 		if (rc != 0)
86 			return rc;
87 
88 		rc = opal_slw_set_reg(pir, SPRN_LPCR, lpcr_val);
89 		if (rc != 0)
90 			return rc;
91 
92 		if (cpu_has_feature(CPU_FTR_ARCH_300)) {
93 			rc = opal_slw_set_reg(pir, P9_STOP_SPR_MSR, msr_val);
94 			if (rc)
95 				return rc;
96 
97 			rc = opal_slw_set_reg(pir,
98 					      P9_STOP_SPR_PSSCR, psscr_val);
99 
100 			if (rc)
101 				return rc;
102 		}
103 
104 		/* HIDs are per core registers */
105 		if (cpu_thread_in_core(cpu) == 0) {
106 
107 			rc = opal_slw_set_reg(pir, SPRN_HMEER, hmeer_val);
108 			if (rc != 0)
109 				return rc;
110 
111 			rc = opal_slw_set_reg(pir, SPRN_HID0, hid0_val);
112 			if (rc != 0)
113 				return rc;
114 
115 			/* Only p8 needs to set extra HID registers */
116 			if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
117 				uint64_t hid1_val = mfspr(SPRN_HID1);
118 				uint64_t hid4_val = mfspr(SPRN_HID4);
119 				uint64_t hid5_val = mfspr(SPRN_HID5);
120 
121 				rc = opal_slw_set_reg(pir, SPRN_HID1, hid1_val);
122 				if (rc != 0)
123 					return rc;
124 
125 				rc = opal_slw_set_reg(pir, SPRN_HID4, hid4_val);
126 				if (rc != 0)
127 					return rc;
128 
129 				rc = opal_slw_set_reg(pir, SPRN_HID5, hid5_val);
130 				if (rc != 0)
131 					return rc;
132 			}
133 		}
134 	}
135 
136 	return 0;
137 }
138 
139 u32 pnv_get_supported_cpuidle_states(void)
140 {
141 	return supported_cpuidle_states;
142 }
143 EXPORT_SYMBOL_GPL(pnv_get_supported_cpuidle_states);
144 
145 static void pnv_fastsleep_workaround_apply(void *info)
146 
147 {
148 	int cpu = smp_processor_id();
149 	int rc;
150 	int *err = info;
151 
152 	if (cpu_first_thread_sibling(cpu) != cpu)
153 		return;
154 
155 	rc = opal_config_cpu_idle_state(OPAL_CONFIG_IDLE_FASTSLEEP,
156 					OPAL_CONFIG_IDLE_APPLY);
157 	if (rc)
158 		*err = 1;
159 }
160 
161 static bool power7_fastsleep_workaround_entry = true;
162 static bool power7_fastsleep_workaround_exit = true;
163 
164 /*
165  * Used to store fastsleep workaround state
166  * 0 - Workaround applied/undone at fastsleep entry/exit path (Default)
167  * 1 - Workaround applied once, never undone.
168  */
169 static u8 fastsleep_workaround_applyonce;
170 
171 static ssize_t show_fastsleep_workaround_applyonce(struct device *dev,
172 		struct device_attribute *attr, char *buf)
173 {
174 	return sprintf(buf, "%u\n", fastsleep_workaround_applyonce);
175 }
176 
177 static ssize_t store_fastsleep_workaround_applyonce(struct device *dev,
178 		struct device_attribute *attr, const char *buf,
179 		size_t count)
180 {
181 	int err;
182 	u8 val;
183 
184 	if (kstrtou8(buf, 0, &val) || val != 1)
185 		return -EINVAL;
186 
187 	if (fastsleep_workaround_applyonce == 1)
188 		return count;
189 
190 	/*
191 	 * fastsleep_workaround_applyonce = 1 implies
192 	 * fastsleep workaround needs to be left in 'applied' state on all
193 	 * the cores. Do this by-
194 	 * 1. Disable the 'undo' workaround in fastsleep exit path
195 	 * 2. Sendi IPIs to all the cores which have at least one online thread
196 	 * 3. Disable the 'apply' workaround in fastsleep entry path
197 	 *
198 	 * There is no need to send ipi to cores which have all threads
199 	 * offlined, as last thread of the core entering fastsleep or deeper
200 	 * state would have applied workaround.
201 	 */
202 	power7_fastsleep_workaround_exit = false;
203 
204 	cpus_read_lock();
205 	on_each_cpu(pnv_fastsleep_workaround_apply, &err, 1);
206 	cpus_read_unlock();
207 	if (err) {
208 		pr_err("fastsleep_workaround_applyonce change failed while running pnv_fastsleep_workaround_apply");
209 		goto fail;
210 	}
211 
212 	power7_fastsleep_workaround_entry = false;
213 
214 	fastsleep_workaround_applyonce = 1;
215 
216 	return count;
217 fail:
218 	return -EIO;
219 }
220 
221 static DEVICE_ATTR(fastsleep_workaround_applyonce, 0600,
222 			show_fastsleep_workaround_applyonce,
223 			store_fastsleep_workaround_applyonce);
224 
225 static inline void atomic_start_thread_idle(void)
226 {
227 	int cpu = raw_smp_processor_id();
228 	int first = cpu_first_thread_sibling(cpu);
229 	int thread_nr = cpu_thread_in_core(cpu);
230 	unsigned long *state = &paca_ptrs[first]->idle_state;
231 
232 	clear_bit(thread_nr, state);
233 }
234 
235 static inline void atomic_stop_thread_idle(void)
236 {
237 	int cpu = raw_smp_processor_id();
238 	int first = cpu_first_thread_sibling(cpu);
239 	int thread_nr = cpu_thread_in_core(cpu);
240 	unsigned long *state = &paca_ptrs[first]->idle_state;
241 
242 	set_bit(thread_nr, state);
243 }
244 
245 static inline void atomic_lock_thread_idle(void)
246 {
247 	int cpu = raw_smp_processor_id();
248 	int first = cpu_first_thread_sibling(cpu);
249 	unsigned long *state = &paca_ptrs[first]->idle_state;
250 
251 	while (unlikely(test_and_set_bit_lock(NR_PNV_CORE_IDLE_LOCK_BIT, state)))
252 		barrier();
253 }
254 
255 static inline void atomic_unlock_and_stop_thread_idle(void)
256 {
257 	int cpu = raw_smp_processor_id();
258 	int first = cpu_first_thread_sibling(cpu);
259 	unsigned long thread = 1UL << cpu_thread_in_core(cpu);
260 	unsigned long *state = &paca_ptrs[first]->idle_state;
261 	u64 s = READ_ONCE(*state);
262 	u64 new, tmp;
263 
264 	BUG_ON(!(s & PNV_CORE_IDLE_LOCK_BIT));
265 	BUG_ON(s & thread);
266 
267 again:
268 	new = (s | thread) & ~PNV_CORE_IDLE_LOCK_BIT;
269 	tmp = cmpxchg(state, s, new);
270 	if (unlikely(tmp != s)) {
271 		s = tmp;
272 		goto again;
273 	}
274 }
275 
276 static inline void atomic_unlock_thread_idle(void)
277 {
278 	int cpu = raw_smp_processor_id();
279 	int first = cpu_first_thread_sibling(cpu);
280 	unsigned long *state = &paca_ptrs[first]->idle_state;
281 
282 	BUG_ON(!test_bit(NR_PNV_CORE_IDLE_LOCK_BIT, state));
283 	clear_bit_unlock(NR_PNV_CORE_IDLE_LOCK_BIT, state);
284 }
285 
286 /* P7 and P8 */
287 struct p7_sprs {
288 	/* per core */
289 	u64 tscr;
290 	u64 worc;
291 
292 	/* per subcore */
293 	u64 sdr1;
294 	u64 rpr;
295 
296 	/* per thread */
297 	u64 lpcr;
298 	u64 hfscr;
299 	u64 fscr;
300 	u64 purr;
301 	u64 spurr;
302 	u64 dscr;
303 	u64 wort;
304 
305 	/* per thread SPRs that get lost in shallow states */
306 	u64 amr;
307 	u64 iamr;
308 	u64 uamor;
309 	/* amor is restored to constant ~0 */
310 };
311 
312 static unsigned long power7_idle_insn(unsigned long type)
313 {
314 	int cpu = raw_smp_processor_id();
315 	int first = cpu_first_thread_sibling(cpu);
316 	unsigned long *state = &paca_ptrs[first]->idle_state;
317 	unsigned long thread = 1UL << cpu_thread_in_core(cpu);
318 	unsigned long core_thread_mask = (1UL << threads_per_core) - 1;
319 	unsigned long srr1;
320 	bool full_winkle;
321 	struct p7_sprs sprs = {}; /* avoid false use-uninitialised */
322 	bool sprs_saved = false;
323 	int rc;
324 
325 	if (unlikely(type != PNV_THREAD_NAP)) {
326 		atomic_lock_thread_idle();
327 
328 		BUG_ON(!(*state & thread));
329 		*state &= ~thread;
330 
331 		if (power7_fastsleep_workaround_entry) {
332 			if ((*state & core_thread_mask) == 0) {
333 				rc = opal_config_cpu_idle_state(
334 						OPAL_CONFIG_IDLE_FASTSLEEP,
335 						OPAL_CONFIG_IDLE_APPLY);
336 				BUG_ON(rc);
337 			}
338 		}
339 
340 		if (type == PNV_THREAD_WINKLE) {
341 			sprs.tscr	= mfspr(SPRN_TSCR);
342 			sprs.worc	= mfspr(SPRN_WORC);
343 
344 			sprs.sdr1	= mfspr(SPRN_SDR1);
345 			sprs.rpr	= mfspr(SPRN_RPR);
346 
347 			sprs.lpcr	= mfspr(SPRN_LPCR);
348 			if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
349 				sprs.hfscr	= mfspr(SPRN_HFSCR);
350 				sprs.fscr	= mfspr(SPRN_FSCR);
351 			}
352 			sprs.purr	= mfspr(SPRN_PURR);
353 			sprs.spurr	= mfspr(SPRN_SPURR);
354 			sprs.dscr	= mfspr(SPRN_DSCR);
355 			sprs.wort	= mfspr(SPRN_WORT);
356 
357 			sprs_saved = true;
358 
359 			/*
360 			 * Increment winkle counter and set all winkle bits if
361 			 * all threads are winkling. This allows wakeup side to
362 			 * distinguish between fast sleep and winkle state
363 			 * loss. Fast sleep still has to resync the timebase so
364 			 * this may not be a really big win.
365 			 */
366 			*state += 1 << PNV_CORE_IDLE_WINKLE_COUNT_SHIFT;
367 			if ((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS)
368 					>> PNV_CORE_IDLE_WINKLE_COUNT_SHIFT
369 					== threads_per_core)
370 				*state |= PNV_CORE_IDLE_THREAD_WINKLE_BITS;
371 			WARN_ON((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS) == 0);
372 		}
373 
374 		atomic_unlock_thread_idle();
375 	}
376 
377 	if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
378 		sprs.amr	= mfspr(SPRN_AMR);
379 		sprs.iamr	= mfspr(SPRN_IAMR);
380 		sprs.uamor	= mfspr(SPRN_UAMOR);
381 	}
382 
383 	local_paca->thread_idle_state = type;
384 	srr1 = isa206_idle_insn_mayloss(type);		/* go idle */
385 	local_paca->thread_idle_state = PNV_THREAD_RUNNING;
386 
387 	WARN_ON_ONCE(!srr1);
388 	WARN_ON_ONCE(mfmsr() & (MSR_IR|MSR_DR));
389 
390 	if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
391 		if ((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS) {
392 			/*
393 			 * We don't need an isync after the mtsprs here because
394 			 * the upcoming mtmsrd is execution synchronizing.
395 			 */
396 			mtspr(SPRN_AMR,		sprs.amr);
397 			mtspr(SPRN_IAMR,	sprs.iamr);
398 			mtspr(SPRN_AMOR,	~0);
399 			mtspr(SPRN_UAMOR,	sprs.uamor);
400 		}
401 	}
402 
403 	if (unlikely((srr1 & SRR1_WAKEMASK_P8) == SRR1_WAKEHMI))
404 		hmi_exception_realmode(NULL);
405 
406 	if (likely((srr1 & SRR1_WAKESTATE) != SRR1_WS_HVLOSS)) {
407 		if (unlikely(type != PNV_THREAD_NAP)) {
408 			atomic_lock_thread_idle();
409 			if (type == PNV_THREAD_WINKLE) {
410 				WARN_ON((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS) == 0);
411 				*state -= 1 << PNV_CORE_IDLE_WINKLE_COUNT_SHIFT;
412 				*state &= ~(thread << PNV_CORE_IDLE_THREAD_WINKLE_BITS_SHIFT);
413 			}
414 			atomic_unlock_and_stop_thread_idle();
415 		}
416 		return srr1;
417 	}
418 
419 	/* HV state loss */
420 	BUG_ON(type == PNV_THREAD_NAP);
421 
422 	atomic_lock_thread_idle();
423 
424 	full_winkle = false;
425 	if (type == PNV_THREAD_WINKLE) {
426 		WARN_ON((*state & PNV_CORE_IDLE_WINKLE_COUNT_BITS) == 0);
427 		*state -= 1 << PNV_CORE_IDLE_WINKLE_COUNT_SHIFT;
428 		if (*state & (thread << PNV_CORE_IDLE_THREAD_WINKLE_BITS_SHIFT)) {
429 			*state &= ~(thread << PNV_CORE_IDLE_THREAD_WINKLE_BITS_SHIFT);
430 			full_winkle = true;
431 			BUG_ON(!sprs_saved);
432 		}
433 	}
434 
435 	WARN_ON(*state & thread);
436 
437 	if ((*state & core_thread_mask) != 0)
438 		goto core_woken;
439 
440 	/* Per-core SPRs */
441 	if (full_winkle) {
442 		mtspr(SPRN_TSCR,	sprs.tscr);
443 		mtspr(SPRN_WORC,	sprs.worc);
444 	}
445 
446 	if (power7_fastsleep_workaround_exit) {
447 		rc = opal_config_cpu_idle_state(OPAL_CONFIG_IDLE_FASTSLEEP,
448 						OPAL_CONFIG_IDLE_UNDO);
449 		BUG_ON(rc);
450 	}
451 
452 	/* TB */
453 	if (opal_resync_timebase() != OPAL_SUCCESS)
454 		BUG();
455 
456 core_woken:
457 	if (!full_winkle)
458 		goto subcore_woken;
459 
460 	if ((*state & local_paca->subcore_sibling_mask) != 0)
461 		goto subcore_woken;
462 
463 	/* Per-subcore SPRs */
464 	mtspr(SPRN_SDR1,	sprs.sdr1);
465 	mtspr(SPRN_RPR,		sprs.rpr);
466 
467 subcore_woken:
468 	/*
469 	 * isync after restoring shared SPRs and before unlocking. Unlock
470 	 * only contains hwsync which does not necessarily do the right
471 	 * thing for SPRs.
472 	 */
473 	isync();
474 	atomic_unlock_and_stop_thread_idle();
475 
476 	/* Fast sleep does not lose SPRs */
477 	if (!full_winkle)
478 		return srr1;
479 
480 	/* Per-thread SPRs */
481 	mtspr(SPRN_LPCR,	sprs.lpcr);
482 	if (cpu_has_feature(CPU_FTR_ARCH_207S)) {
483 		mtspr(SPRN_HFSCR,	sprs.hfscr);
484 		mtspr(SPRN_FSCR,	sprs.fscr);
485 	}
486 	mtspr(SPRN_PURR,	sprs.purr);
487 	mtspr(SPRN_SPURR,	sprs.spurr);
488 	mtspr(SPRN_DSCR,	sprs.dscr);
489 	mtspr(SPRN_WORT,	sprs.wort);
490 
491 	mtspr(SPRN_SPRG3,	local_paca->sprg_vdso);
492 
493 #ifdef CONFIG_PPC_64S_HASH_MMU
494 	/*
495 	 * The SLB has to be restored here, but it sometimes still
496 	 * contains entries, so the __ variant must be used to prevent
497 	 * multi hits.
498 	 */
499 	__slb_restore_bolted_realmode();
500 #endif
501 
502 	return srr1;
503 }
504 
505 extern unsigned long idle_kvm_start_guest(unsigned long srr1);
506 
507 #ifdef CONFIG_HOTPLUG_CPU
508 static unsigned long power7_offline(void)
509 {
510 	unsigned long srr1;
511 
512 	mtmsr(MSR_IDLE);
513 
514 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
515 	/* Tell KVM we're entering idle. */
516 	/******************************************************/
517 	/*  N O T E   W E L L    ! ! !    N O T E   W E L L   */
518 	/* The following store to HSTATE_HWTHREAD_STATE(r13)  */
519 	/* MUST occur in real mode, i.e. with the MMU off,    */
520 	/* and the MMU must stay off until we clear this flag */
521 	/* and test HSTATE_HWTHREAD_REQ(r13) in               */
522 	/* pnv_powersave_wakeup in this file.                 */
523 	/* The reason is that another thread can switch the   */
524 	/* MMU to a guest context whenever this flag is set   */
525 	/* to KVM_HWTHREAD_IN_IDLE, and if the MMU was on,    */
526 	/* that would potentially cause this thread to start  */
527 	/* executing instructions from guest memory in        */
528 	/* hypervisor mode, leading to a host crash or data   */
529 	/* corruption, or worse.                              */
530 	/******************************************************/
531 	local_paca->kvm_hstate.hwthread_state = KVM_HWTHREAD_IN_IDLE;
532 #endif
533 
534 	__ppc64_runlatch_off();
535 	srr1 = power7_idle_insn(power7_offline_type);
536 	__ppc64_runlatch_on();
537 
538 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
539 	local_paca->kvm_hstate.hwthread_state = KVM_HWTHREAD_IN_KERNEL;
540 	/* Order setting hwthread_state vs. testing hwthread_req */
541 	smp_mb();
542 	if (local_paca->kvm_hstate.hwthread_req)
543 		srr1 = idle_kvm_start_guest(srr1);
544 #endif
545 
546 	mtmsr(MSR_KERNEL);
547 
548 	return srr1;
549 }
550 #endif
551 
552 void power7_idle_type(unsigned long type)
553 {
554 	unsigned long srr1;
555 
556 	if (!prep_irq_for_idle_irqsoff())
557 		return;
558 
559 	mtmsr(MSR_IDLE);
560 	__ppc64_runlatch_off();
561 	srr1 = power7_idle_insn(type);
562 	__ppc64_runlatch_on();
563 	mtmsr(MSR_KERNEL);
564 
565 	fini_irq_for_idle_irqsoff();
566 	irq_set_pending_from_srr1(srr1);
567 }
568 
569 static void power7_idle(void)
570 {
571 	if (!powersave_nap)
572 		return;
573 
574 	power7_idle_type(PNV_THREAD_NAP);
575 }
576 
577 struct p9_sprs {
578 	/* per core */
579 	u64 ptcr;
580 	u64 rpr;
581 	u64 tscr;
582 	u64 ldbar;
583 
584 	/* per thread */
585 	u64 lpcr;
586 	u64 hfscr;
587 	u64 fscr;
588 	u64 pid;
589 	u64 purr;
590 	u64 spurr;
591 	u64 dscr;
592 	u64 ciabr;
593 
594 	u64 mmcra;
595 	u32 mmcr0;
596 	u32 mmcr1;
597 	u64 mmcr2;
598 
599 	/* per thread SPRs that get lost in shallow states */
600 	u64 amr;
601 	u64 iamr;
602 	u64 amor;
603 	u64 uamor;
604 };
605 
606 static unsigned long power9_idle_stop(unsigned long psscr)
607 {
608 	int cpu = raw_smp_processor_id();
609 	int first = cpu_first_thread_sibling(cpu);
610 	unsigned long *state = &paca_ptrs[first]->idle_state;
611 	unsigned long core_thread_mask = (1UL << threads_per_core) - 1;
612 	unsigned long srr1;
613 	unsigned long pls;
614 	unsigned long mmcr0 = 0;
615 	unsigned long mmcra = 0;
616 	struct p9_sprs sprs = {}; /* avoid false used-uninitialised */
617 	bool sprs_saved = false;
618 
619 	if (!(psscr & (PSSCR_EC|PSSCR_ESL))) {
620 		/* EC=ESL=0 case */
621 
622 		/*
623 		 * Wake synchronously. SRESET via xscom may still cause
624 		 * a 0x100 powersave wakeup with SRR1 reason!
625 		 */
626 		srr1 = isa300_idle_stop_noloss(psscr);		/* go idle */
627 		if (likely(!srr1))
628 			return 0;
629 
630 		/*
631 		 * Registers not saved, can't recover!
632 		 * This would be a hardware bug
633 		 */
634 		BUG_ON((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS);
635 
636 		goto out;
637 	}
638 
639 	/* EC=ESL=1 case */
640 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
641 	if (cpu_has_feature(CPU_FTR_P9_TM_XER_SO_BUG)) {
642 		local_paca->requested_psscr = psscr;
643 		/* order setting requested_psscr vs testing dont_stop */
644 		smp_mb();
645 		if (atomic_read(&local_paca->dont_stop)) {
646 			local_paca->requested_psscr = 0;
647 			return 0;
648 		}
649 	}
650 #endif
651 
652 	if (!cpu_has_feature(CPU_FTR_POWER9_DD2_1)) {
653 		 /*
654 		  * POWER9 DD2 can incorrectly set PMAO when waking up
655 		  * after a state-loss idle. Saving and restoring MMCR0
656 		  * over idle is a workaround.
657 		  */
658 		mmcr0		= mfspr(SPRN_MMCR0);
659 	}
660 
661 	if ((psscr & PSSCR_RL_MASK) >= deep_spr_loss_state) {
662 		sprs.lpcr	= mfspr(SPRN_LPCR);
663 		sprs.hfscr	= mfspr(SPRN_HFSCR);
664 		sprs.fscr	= mfspr(SPRN_FSCR);
665 		sprs.pid	= mfspr(SPRN_PID);
666 		sprs.purr	= mfspr(SPRN_PURR);
667 		sprs.spurr	= mfspr(SPRN_SPURR);
668 		sprs.dscr	= mfspr(SPRN_DSCR);
669 		sprs.ciabr	= mfspr(SPRN_CIABR);
670 
671 		sprs.mmcra	= mfspr(SPRN_MMCRA);
672 		sprs.mmcr0	= mfspr(SPRN_MMCR0);
673 		sprs.mmcr1	= mfspr(SPRN_MMCR1);
674 		sprs.mmcr2	= mfspr(SPRN_MMCR2);
675 
676 		sprs.ptcr	= mfspr(SPRN_PTCR);
677 		sprs.rpr	= mfspr(SPRN_RPR);
678 		sprs.tscr	= mfspr(SPRN_TSCR);
679 		if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
680 			sprs.ldbar = mfspr(SPRN_LDBAR);
681 
682 		sprs_saved = true;
683 
684 		atomic_start_thread_idle();
685 	}
686 
687 	sprs.amr	= mfspr(SPRN_AMR);
688 	sprs.iamr	= mfspr(SPRN_IAMR);
689 	sprs.uamor	= mfspr(SPRN_UAMOR);
690 
691 	srr1 = isa300_idle_stop_mayloss(psscr);		/* go idle */
692 
693 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
694 	local_paca->requested_psscr = 0;
695 #endif
696 
697 	psscr = mfspr(SPRN_PSSCR);
698 
699 	WARN_ON_ONCE(!srr1);
700 	WARN_ON_ONCE(mfmsr() & (MSR_IR|MSR_DR));
701 
702 	if ((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS) {
703 		/*
704 		 * We don't need an isync after the mtsprs here because the
705 		 * upcoming mtmsrd is execution synchronizing.
706 		 */
707 		mtspr(SPRN_AMR,		sprs.amr);
708 		mtspr(SPRN_IAMR,	sprs.iamr);
709 		mtspr(SPRN_AMOR,	~0);
710 		mtspr(SPRN_UAMOR,	sprs.uamor);
711 
712 		/*
713 		 * Workaround for POWER9 DD2.0, if we lost resources, the ERAT
714 		 * might have been corrupted and needs flushing. We also need
715 		 * to reload MMCR0 (see mmcr0 comment above).
716 		 */
717 		if (!cpu_has_feature(CPU_FTR_POWER9_DD2_1)) {
718 			asm volatile(PPC_ISA_3_0_INVALIDATE_ERAT);
719 			mtspr(SPRN_MMCR0, mmcr0);
720 		}
721 
722 		/*
723 		 * DD2.2 and earlier need to set then clear bit 60 in MMCRA
724 		 * to ensure the PMU starts running.
725 		 */
726 		mmcra = mfspr(SPRN_MMCRA);
727 		mmcra |= PPC_BIT(60);
728 		mtspr(SPRN_MMCRA, mmcra);
729 		mmcra &= ~PPC_BIT(60);
730 		mtspr(SPRN_MMCRA, mmcra);
731 	}
732 
733 	if (unlikely((srr1 & SRR1_WAKEMASK_P8) == SRR1_WAKEHMI))
734 		hmi_exception_realmode(NULL);
735 
736 	/*
737 	 * On POWER9, SRR1 bits do not match exactly as expected.
738 	 * SRR1_WS_GPRLOSS (10b) can also result in SPR loss, so
739 	 * just always test PSSCR for SPR/TB state loss.
740 	 */
741 	pls = (psscr & PSSCR_PLS) >> PSSCR_PLS_SHIFT;
742 	if (likely(pls < deep_spr_loss_state)) {
743 		if (sprs_saved)
744 			atomic_stop_thread_idle();
745 		goto out;
746 	}
747 
748 	/* HV state loss */
749 	BUG_ON(!sprs_saved);
750 
751 	atomic_lock_thread_idle();
752 
753 	if ((*state & core_thread_mask) != 0)
754 		goto core_woken;
755 
756 	/* Per-core SPRs */
757 	mtspr(SPRN_PTCR,	sprs.ptcr);
758 	mtspr(SPRN_RPR,		sprs.rpr);
759 	mtspr(SPRN_TSCR,	sprs.tscr);
760 
761 	if (pls >= pnv_first_tb_loss_level) {
762 		/* TB loss */
763 		if (opal_resync_timebase() != OPAL_SUCCESS)
764 			BUG();
765 	}
766 
767 	/*
768 	 * isync after restoring shared SPRs and before unlocking. Unlock
769 	 * only contains hwsync which does not necessarily do the right
770 	 * thing for SPRs.
771 	 */
772 	isync();
773 
774 core_woken:
775 	atomic_unlock_and_stop_thread_idle();
776 
777 	/* Per-thread SPRs */
778 	mtspr(SPRN_LPCR,	sprs.lpcr);
779 	mtspr(SPRN_HFSCR,	sprs.hfscr);
780 	mtspr(SPRN_FSCR,	sprs.fscr);
781 	mtspr(SPRN_PID,		sprs.pid);
782 	mtspr(SPRN_PURR,	sprs.purr);
783 	mtspr(SPRN_SPURR,	sprs.spurr);
784 	mtspr(SPRN_DSCR,	sprs.dscr);
785 	mtspr(SPRN_CIABR,	sprs.ciabr);
786 
787 	mtspr(SPRN_MMCRA,	sprs.mmcra);
788 	mtspr(SPRN_MMCR0,	sprs.mmcr0);
789 	mtspr(SPRN_MMCR1,	sprs.mmcr1);
790 	mtspr(SPRN_MMCR2,	sprs.mmcr2);
791 	if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
792 		mtspr(SPRN_LDBAR, sprs.ldbar);
793 
794 	mtspr(SPRN_SPRG3,	local_paca->sprg_vdso);
795 
796 	if (!radix_enabled())
797 		__slb_restore_bolted_realmode();
798 
799 out:
800 	mtmsr(MSR_KERNEL);
801 
802 	return srr1;
803 }
804 
805 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
806 /*
807  * This is used in working around bugs in thread reconfiguration
808  * on POWER9 (at least up to Nimbus DD2.2) relating to transactional
809  * memory and the way that XER[SO] is checkpointed.
810  * This function forces the core into SMT4 in order by asking
811  * all other threads not to stop, and sending a message to any
812  * that are in a stop state.
813  * Must be called with preemption disabled.
814  */
815 void pnv_power9_force_smt4_catch(void)
816 {
817 	int cpu, cpu0, thr;
818 	int awake_threads = 1;		/* this thread is awake */
819 	int poke_threads = 0;
820 	int need_awake = threads_per_core;
821 
822 	cpu = smp_processor_id();
823 	cpu0 = cpu & ~(threads_per_core - 1);
824 	for (thr = 0; thr < threads_per_core; ++thr) {
825 		if (cpu != cpu0 + thr)
826 			atomic_inc(&paca_ptrs[cpu0+thr]->dont_stop);
827 	}
828 	/* order setting dont_stop vs testing requested_psscr */
829 	smp_mb();
830 	for (thr = 0; thr < threads_per_core; ++thr) {
831 		if (!paca_ptrs[cpu0+thr]->requested_psscr)
832 			++awake_threads;
833 		else
834 			poke_threads |= (1 << thr);
835 	}
836 
837 	/* If at least 3 threads are awake, the core is in SMT4 already */
838 	if (awake_threads < need_awake) {
839 		/* We have to wake some threads; we'll use msgsnd */
840 		for (thr = 0; thr < threads_per_core; ++thr) {
841 			if (poke_threads & (1 << thr)) {
842 				ppc_msgsnd_sync();
843 				ppc_msgsnd(PPC_DBELL_MSGTYPE, 0,
844 					   paca_ptrs[cpu0+thr]->hw_cpu_id);
845 			}
846 		}
847 		/* now spin until at least 3 threads are awake */
848 		do {
849 			for (thr = 0; thr < threads_per_core; ++thr) {
850 				if ((poke_threads & (1 << thr)) &&
851 				    !paca_ptrs[cpu0+thr]->requested_psscr) {
852 					++awake_threads;
853 					poke_threads &= ~(1 << thr);
854 				}
855 			}
856 		} while (awake_threads < need_awake);
857 	}
858 }
859 EXPORT_SYMBOL_GPL(pnv_power9_force_smt4_catch);
860 
861 void pnv_power9_force_smt4_release(void)
862 {
863 	int cpu, cpu0, thr;
864 
865 	cpu = smp_processor_id();
866 	cpu0 = cpu & ~(threads_per_core - 1);
867 
868 	/* clear all the dont_stop flags */
869 	for (thr = 0; thr < threads_per_core; ++thr) {
870 		if (cpu != cpu0 + thr)
871 			atomic_dec(&paca_ptrs[cpu0+thr]->dont_stop);
872 	}
873 }
874 EXPORT_SYMBOL_GPL(pnv_power9_force_smt4_release);
875 #endif /* CONFIG_KVM_BOOK3S_HV_POSSIBLE */
876 
877 struct p10_sprs {
878 	/*
879 	 * SPRs that get lost in shallow states:
880 	 *
881 	 * P10 loses CR, LR, CTR, FPSCR, VSCR, XER, TAR, SPRG2, and HSPRG1
882 	 * isa300 idle routines restore CR, LR.
883 	 * CTR is volatile
884 	 * idle thread doesn't use FP or VEC
885 	 * kernel doesn't use TAR
886 	 * HSPRG1 is only live in HV interrupt entry
887 	 * SPRG2 is only live in KVM guests, KVM handles it.
888 	 */
889 };
890 
891 static unsigned long power10_idle_stop(unsigned long psscr)
892 {
893 	int cpu = raw_smp_processor_id();
894 	int first = cpu_first_thread_sibling(cpu);
895 	unsigned long *state = &paca_ptrs[first]->idle_state;
896 	unsigned long core_thread_mask = (1UL << threads_per_core) - 1;
897 	unsigned long srr1;
898 	unsigned long pls;
899 //	struct p10_sprs sprs = {}; /* avoid false used-uninitialised */
900 	bool sprs_saved = false;
901 
902 	if (!(psscr & (PSSCR_EC|PSSCR_ESL))) {
903 		/* EC=ESL=0 case */
904 
905 		/*
906 		 * Wake synchronously. SRESET via xscom may still cause
907 		 * a 0x100 powersave wakeup with SRR1 reason!
908 		 */
909 		srr1 = isa300_idle_stop_noloss(psscr);		/* go idle */
910 		if (likely(!srr1))
911 			return 0;
912 
913 		/*
914 		 * Registers not saved, can't recover!
915 		 * This would be a hardware bug
916 		 */
917 		BUG_ON((srr1 & SRR1_WAKESTATE) != SRR1_WS_NOLOSS);
918 
919 		goto out;
920 	}
921 
922 	/* EC=ESL=1 case */
923 	if ((psscr & PSSCR_RL_MASK) >= deep_spr_loss_state) {
924 		/* XXX: save SPRs for deep state loss here. */
925 
926 		sprs_saved = true;
927 
928 		atomic_start_thread_idle();
929 	}
930 
931 	srr1 = isa300_idle_stop_mayloss(psscr);		/* go idle */
932 
933 	psscr = mfspr(SPRN_PSSCR);
934 
935 	WARN_ON_ONCE(!srr1);
936 	WARN_ON_ONCE(mfmsr() & (MSR_IR|MSR_DR));
937 
938 	if (unlikely((srr1 & SRR1_WAKEMASK_P8) == SRR1_WAKEHMI))
939 		hmi_exception_realmode(NULL);
940 
941 	/*
942 	 * On POWER10, SRR1 bits do not match exactly as expected.
943 	 * SRR1_WS_GPRLOSS (10b) can also result in SPR loss, so
944 	 * just always test PSSCR for SPR/TB state loss.
945 	 */
946 	pls = (psscr & PSSCR_PLS) >> PSSCR_PLS_SHIFT;
947 	if (likely(pls < deep_spr_loss_state)) {
948 		if (sprs_saved)
949 			atomic_stop_thread_idle();
950 		goto out;
951 	}
952 
953 	/* HV state loss */
954 	BUG_ON(!sprs_saved);
955 
956 	atomic_lock_thread_idle();
957 
958 	if ((*state & core_thread_mask) != 0)
959 		goto core_woken;
960 
961 	/* XXX: restore per-core SPRs here */
962 
963 	if (pls >= pnv_first_tb_loss_level) {
964 		/* TB loss */
965 		if (opal_resync_timebase() != OPAL_SUCCESS)
966 			BUG();
967 	}
968 
969 	/*
970 	 * isync after restoring shared SPRs and before unlocking. Unlock
971 	 * only contains hwsync which does not necessarily do the right
972 	 * thing for SPRs.
973 	 */
974 	isync();
975 
976 core_woken:
977 	atomic_unlock_and_stop_thread_idle();
978 
979 	/* XXX: restore per-thread SPRs here */
980 
981 	if (!radix_enabled())
982 		__slb_restore_bolted_realmode();
983 
984 out:
985 	mtmsr(MSR_KERNEL);
986 
987 	return srr1;
988 }
989 
990 #ifdef CONFIG_HOTPLUG_CPU
991 static unsigned long arch300_offline_stop(unsigned long psscr)
992 {
993 	unsigned long srr1;
994 
995 	if (cpu_has_feature(CPU_FTR_ARCH_31))
996 		srr1 = power10_idle_stop(psscr);
997 	else
998 		srr1 = power9_idle_stop(psscr);
999 
1000 	return srr1;
1001 }
1002 #endif
1003 
1004 void arch300_idle_type(unsigned long stop_psscr_val,
1005 				      unsigned long stop_psscr_mask)
1006 {
1007 	unsigned long psscr;
1008 	unsigned long srr1;
1009 
1010 	if (!prep_irq_for_idle_irqsoff())
1011 		return;
1012 
1013 	psscr = mfspr(SPRN_PSSCR);
1014 	psscr = (psscr & ~stop_psscr_mask) | stop_psscr_val;
1015 
1016 	__ppc64_runlatch_off();
1017 	if (cpu_has_feature(CPU_FTR_ARCH_31))
1018 		srr1 = power10_idle_stop(psscr);
1019 	else
1020 		srr1 = power9_idle_stop(psscr);
1021 	__ppc64_runlatch_on();
1022 
1023 	fini_irq_for_idle_irqsoff();
1024 
1025 	irq_set_pending_from_srr1(srr1);
1026 }
1027 
1028 /*
1029  * Used for ppc_md.power_save which needs a function with no parameters
1030  */
1031 static void arch300_idle(void)
1032 {
1033 	arch300_idle_type(pnv_default_stop_val, pnv_default_stop_mask);
1034 }
1035 
1036 #ifdef CONFIG_HOTPLUG_CPU
1037 
1038 void pnv_program_cpu_hotplug_lpcr(unsigned int cpu, u64 lpcr_val)
1039 {
1040 	u64 pir = get_hard_smp_processor_id(cpu);
1041 
1042 	mtspr(SPRN_LPCR, lpcr_val);
1043 
1044 	/*
1045 	 * Program the LPCR via stop-api only if the deepest stop state
1046 	 * can lose hypervisor context.
1047 	 */
1048 	if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT)
1049 		opal_slw_set_reg(pir, SPRN_LPCR, lpcr_val);
1050 }
1051 
1052 /*
1053  * pnv_cpu_offline: A function that puts the CPU into the deepest
1054  * available platform idle state on a CPU-Offline.
1055  * interrupts hard disabled and no lazy irq pending.
1056  */
1057 unsigned long pnv_cpu_offline(unsigned int cpu)
1058 {
1059 	unsigned long srr1;
1060 
1061 	__ppc64_runlatch_off();
1062 
1063 	if (cpu_has_feature(CPU_FTR_ARCH_300) && deepest_stop_found) {
1064 		unsigned long psscr;
1065 
1066 		psscr = mfspr(SPRN_PSSCR);
1067 		psscr = (psscr & ~pnv_deepest_stop_psscr_mask) |
1068 						pnv_deepest_stop_psscr_val;
1069 		srr1 = arch300_offline_stop(psscr);
1070 	} else if (cpu_has_feature(CPU_FTR_ARCH_206) && power7_offline_type) {
1071 		srr1 = power7_offline();
1072 	} else {
1073 		/* This is the fallback method. We emulate snooze */
1074 		while (!generic_check_cpu_restart(cpu)) {
1075 			HMT_low();
1076 			HMT_very_low();
1077 		}
1078 		srr1 = 0;
1079 		HMT_medium();
1080 	}
1081 
1082 	__ppc64_runlatch_on();
1083 
1084 	return srr1;
1085 }
1086 #endif
1087 
1088 /*
1089  * Power ISA 3.0 idle initialization.
1090  *
1091  * POWER ISA 3.0 defines a new SPR Processor stop Status and Control
1092  * Register (PSSCR) to control idle behavior.
1093  *
1094  * PSSCR layout:
1095  * ----------------------------------------------------------
1096  * | PLS | /// | SD | ESL | EC | PSLL | /// | TR | MTL | RL |
1097  * ----------------------------------------------------------
1098  * 0      4     41   42    43   44     48    54   56    60
1099  *
1100  * PSSCR key fields:
1101  *	Bits 0:3  - Power-Saving Level Status (PLS). This field indicates the
1102  *	lowest power-saving state the thread entered since stop instruction was
1103  *	last executed.
1104  *
1105  *	Bit 41 - Status Disable(SD)
1106  *	0 - Shows PLS entries
1107  *	1 - PLS entries are all 0
1108  *
1109  *	Bit 42 - Enable State Loss
1110  *	0 - No state is lost irrespective of other fields
1111  *	1 - Allows state loss
1112  *
1113  *	Bit 43 - Exit Criterion
1114  *	0 - Exit from power-save mode on any interrupt
1115  *	1 - Exit from power-save mode controlled by LPCR's PECE bits
1116  *
1117  *	Bits 44:47 - Power-Saving Level Limit
1118  *	This limits the power-saving level that can be entered into.
1119  *
1120  *	Bits 60:63 - Requested Level
1121  *	Used to specify which power-saving level must be entered on executing
1122  *	stop instruction
1123  */
1124 
1125 int __init validate_psscr_val_mask(u64 *psscr_val, u64 *psscr_mask, u32 flags)
1126 {
1127 	int err = 0;
1128 
1129 	/*
1130 	 * psscr_mask == 0xf indicates an older firmware.
1131 	 * Set remaining fields of psscr to the default values.
1132 	 * See NOTE above definition of PSSCR_HV_DEFAULT_VAL
1133 	 */
1134 	if (*psscr_mask == 0xf) {
1135 		*psscr_val = *psscr_val | PSSCR_HV_DEFAULT_VAL;
1136 		*psscr_mask = PSSCR_HV_DEFAULT_MASK;
1137 		return err;
1138 	}
1139 
1140 	/*
1141 	 * New firmware is expected to set the psscr_val bits correctly.
1142 	 * Validate that the following invariants are correctly maintained by
1143 	 * the new firmware.
1144 	 * - ESL bit value matches the EC bit value.
1145 	 * - ESL bit is set for all the deep stop states.
1146 	 */
1147 	if (GET_PSSCR_ESL(*psscr_val) != GET_PSSCR_EC(*psscr_val)) {
1148 		err = ERR_EC_ESL_MISMATCH;
1149 	} else if ((flags & OPAL_PM_LOSE_FULL_CONTEXT) &&
1150 		GET_PSSCR_ESL(*psscr_val) == 0) {
1151 		err = ERR_DEEP_STATE_ESL_MISMATCH;
1152 	}
1153 
1154 	return err;
1155 }
1156 
1157 /*
1158  * pnv_arch300_idle_init: Initializes the default idle state, first
1159  *                        deep idle state and deepest idle state on
1160  *                        ISA 3.0 CPUs.
1161  *
1162  * @np: /ibm,opal/power-mgt device node
1163  * @flags: cpu-idle-state-flags array
1164  * @dt_idle_states: Number of idle state entries
1165  * Returns 0 on success
1166  */
1167 static void __init pnv_arch300_idle_init(void)
1168 {
1169 	u64 max_residency_ns = 0;
1170 	int i;
1171 
1172 	/* stop is not really architected, we only have p9,p10 drivers */
1173 	if (!pvr_version_is(PVR_POWER10) && !pvr_version_is(PVR_POWER9))
1174 		return;
1175 
1176 	/*
1177 	 * pnv_deepest_stop_{val,mask} should be set to values corresponding to
1178 	 * the deepest stop state.
1179 	 *
1180 	 * pnv_default_stop_{val,mask} should be set to values corresponding to
1181 	 * the deepest loss-less (OPAL_PM_STOP_INST_FAST) stop state.
1182 	 */
1183 	pnv_first_tb_loss_level = MAX_STOP_STATE + 1;
1184 	deep_spr_loss_state = MAX_STOP_STATE + 1;
1185 	for (i = 0; i < nr_pnv_idle_states; i++) {
1186 		int err;
1187 		struct pnv_idle_states_t *state = &pnv_idle_states[i];
1188 		u64 psscr_rl = state->psscr_val & PSSCR_RL_MASK;
1189 
1190 		/* No deep loss driver implemented for POWER10 yet */
1191 		if (pvr_version_is(PVR_POWER10) &&
1192 				state->flags & (OPAL_PM_TIMEBASE_STOP|OPAL_PM_LOSE_FULL_CONTEXT))
1193 			continue;
1194 
1195 		if ((state->flags & OPAL_PM_TIMEBASE_STOP) &&
1196 		     (pnv_first_tb_loss_level > psscr_rl))
1197 			pnv_first_tb_loss_level = psscr_rl;
1198 
1199 		if ((state->flags & OPAL_PM_LOSE_FULL_CONTEXT) &&
1200 		     (deep_spr_loss_state > psscr_rl))
1201 			deep_spr_loss_state = psscr_rl;
1202 
1203 		/*
1204 		 * The idle code does not deal with TB loss occurring
1205 		 * in a shallower state than SPR loss, so force it to
1206 		 * behave like SPRs are lost if TB is lost. POWER9 would
1207 		 * never encounter this, but a POWER8 core would if it
1208 		 * implemented the stop instruction. So this is for forward
1209 		 * compatibility.
1210 		 */
1211 		if ((state->flags & OPAL_PM_TIMEBASE_STOP) &&
1212 		     (deep_spr_loss_state > psscr_rl))
1213 			deep_spr_loss_state = psscr_rl;
1214 
1215 		err = validate_psscr_val_mask(&state->psscr_val,
1216 					      &state->psscr_mask,
1217 					      state->flags);
1218 		if (err) {
1219 			report_invalid_psscr_val(state->psscr_val, err);
1220 			continue;
1221 		}
1222 
1223 		state->valid = true;
1224 
1225 		if (max_residency_ns < state->residency_ns) {
1226 			max_residency_ns = state->residency_ns;
1227 			pnv_deepest_stop_psscr_val = state->psscr_val;
1228 			pnv_deepest_stop_psscr_mask = state->psscr_mask;
1229 			pnv_deepest_stop_flag = state->flags;
1230 			deepest_stop_found = true;
1231 		}
1232 
1233 		if (!default_stop_found &&
1234 		    (state->flags & OPAL_PM_STOP_INST_FAST)) {
1235 			pnv_default_stop_val = state->psscr_val;
1236 			pnv_default_stop_mask = state->psscr_mask;
1237 			default_stop_found = true;
1238 			WARN_ON(state->flags & OPAL_PM_LOSE_FULL_CONTEXT);
1239 		}
1240 	}
1241 
1242 	if (unlikely(!default_stop_found)) {
1243 		pr_warn("cpuidle-powernv: No suitable default stop state found. Disabling platform idle.\n");
1244 	} else {
1245 		ppc_md.power_save = arch300_idle;
1246 		pr_info("cpuidle-powernv: Default stop: psscr = 0x%016llx,mask=0x%016llx\n",
1247 			pnv_default_stop_val, pnv_default_stop_mask);
1248 	}
1249 
1250 	if (unlikely(!deepest_stop_found)) {
1251 		pr_warn("cpuidle-powernv: No suitable stop state for CPU-Hotplug. Offlined CPUs will busy wait");
1252 	} else {
1253 		pr_info("cpuidle-powernv: Deepest stop: psscr = 0x%016llx,mask=0x%016llx\n",
1254 			pnv_deepest_stop_psscr_val,
1255 			pnv_deepest_stop_psscr_mask);
1256 	}
1257 
1258 	pr_info("cpuidle-powernv: First stop level that may lose SPRs = 0x%llx\n",
1259 		deep_spr_loss_state);
1260 
1261 	pr_info("cpuidle-powernv: First stop level that may lose timebase = 0x%llx\n",
1262 		pnv_first_tb_loss_level);
1263 }
1264 
1265 static void __init pnv_disable_deep_states(void)
1266 {
1267 	/*
1268 	 * The stop-api is unable to restore hypervisor
1269 	 * resources on wakeup from platform idle states which
1270 	 * lose full context. So disable such states.
1271 	 */
1272 	supported_cpuidle_states &= ~OPAL_PM_LOSE_FULL_CONTEXT;
1273 	pr_warn("cpuidle-powernv: Disabling idle states that lose full context\n");
1274 	pr_warn("cpuidle-powernv: Idle power-savings, CPU-Hotplug affected\n");
1275 
1276 	if (cpu_has_feature(CPU_FTR_ARCH_300) &&
1277 	    (pnv_deepest_stop_flag & OPAL_PM_LOSE_FULL_CONTEXT)) {
1278 		/*
1279 		 * Use the default stop state for CPU-Hotplug
1280 		 * if available.
1281 		 */
1282 		if (default_stop_found) {
1283 			pnv_deepest_stop_psscr_val = pnv_default_stop_val;
1284 			pnv_deepest_stop_psscr_mask = pnv_default_stop_mask;
1285 			pr_warn("cpuidle-powernv: Offlined CPUs will stop with psscr = 0x%016llx\n",
1286 				pnv_deepest_stop_psscr_val);
1287 		} else { /* Fallback to snooze loop for CPU-Hotplug */
1288 			deepest_stop_found = false;
1289 			pr_warn("cpuidle-powernv: Offlined CPUs will busy wait\n");
1290 		}
1291 	}
1292 }
1293 
1294 /*
1295  * Probe device tree for supported idle states
1296  */
1297 static void __init pnv_probe_idle_states(void)
1298 {
1299 	int i;
1300 
1301 	if (nr_pnv_idle_states < 0) {
1302 		pr_warn("cpuidle-powernv: no idle states found in the DT\n");
1303 		return;
1304 	}
1305 
1306 	if (cpu_has_feature(CPU_FTR_ARCH_300))
1307 		pnv_arch300_idle_init();
1308 
1309 	for (i = 0; i < nr_pnv_idle_states; i++)
1310 		supported_cpuidle_states |= pnv_idle_states[i].flags;
1311 }
1312 
1313 /*
1314  * This function parses device-tree and populates all the information
1315  * into pnv_idle_states structure. It also sets up nr_pnv_idle_states
1316  * which is the number of cpuidle states discovered through device-tree.
1317  */
1318 
1319 static int __init pnv_parse_cpuidle_dt(void)
1320 {
1321 	struct device_node *np;
1322 	int nr_idle_states, i;
1323 	int rc = 0;
1324 	u32 *temp_u32;
1325 	u64 *temp_u64;
1326 	const char **temp_string;
1327 
1328 	np = of_find_node_by_path("/ibm,opal/power-mgt");
1329 	if (!np) {
1330 		pr_warn("opal: PowerMgmt Node not found\n");
1331 		return -ENODEV;
1332 	}
1333 	nr_idle_states = of_property_count_u32_elems(np,
1334 						"ibm,cpu-idle-state-flags");
1335 
1336 	pnv_idle_states = kcalloc(nr_idle_states, sizeof(*pnv_idle_states),
1337 				  GFP_KERNEL);
1338 	temp_u32 = kcalloc(nr_idle_states, sizeof(u32),  GFP_KERNEL);
1339 	temp_u64 = kcalloc(nr_idle_states, sizeof(u64),  GFP_KERNEL);
1340 	temp_string = kcalloc(nr_idle_states, sizeof(char *),  GFP_KERNEL);
1341 
1342 	if (!(pnv_idle_states && temp_u32 && temp_u64 && temp_string)) {
1343 		pr_err("Could not allocate memory for dt parsing\n");
1344 		rc = -ENOMEM;
1345 		goto out;
1346 	}
1347 
1348 	/* Read flags */
1349 	if (of_property_read_u32_array(np, "ibm,cpu-idle-state-flags",
1350 				       temp_u32, nr_idle_states)) {
1351 		pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-flags in DT\n");
1352 		rc = -EINVAL;
1353 		goto out;
1354 	}
1355 	for (i = 0; i < nr_idle_states; i++)
1356 		pnv_idle_states[i].flags = temp_u32[i];
1357 
1358 	/* Read latencies */
1359 	if (of_property_read_u32_array(np, "ibm,cpu-idle-state-latencies-ns",
1360 				       temp_u32, nr_idle_states)) {
1361 		pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-latencies-ns in DT\n");
1362 		rc = -EINVAL;
1363 		goto out;
1364 	}
1365 	for (i = 0; i < nr_idle_states; i++)
1366 		pnv_idle_states[i].latency_ns = temp_u32[i];
1367 
1368 	/* Read residencies */
1369 	if (of_property_read_u32_array(np, "ibm,cpu-idle-state-residency-ns",
1370 				       temp_u32, nr_idle_states)) {
1371 		pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-residency-ns in DT\n");
1372 		rc = -EINVAL;
1373 		goto out;
1374 	}
1375 	for (i = 0; i < nr_idle_states; i++)
1376 		pnv_idle_states[i].residency_ns = temp_u32[i];
1377 
1378 	/* For power9 and later */
1379 	if (cpu_has_feature(CPU_FTR_ARCH_300)) {
1380 		/* Read pm_crtl_val */
1381 		if (of_property_read_u64_array(np, "ibm,cpu-idle-state-psscr",
1382 					       temp_u64, nr_idle_states)) {
1383 			pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n");
1384 			rc = -EINVAL;
1385 			goto out;
1386 		}
1387 		for (i = 0; i < nr_idle_states; i++)
1388 			pnv_idle_states[i].psscr_val = temp_u64[i];
1389 
1390 		/* Read pm_crtl_mask */
1391 		if (of_property_read_u64_array(np, "ibm,cpu-idle-state-psscr-mask",
1392 					       temp_u64, nr_idle_states)) {
1393 			pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr-mask in DT\n");
1394 			rc = -EINVAL;
1395 			goto out;
1396 		}
1397 		for (i = 0; i < nr_idle_states; i++)
1398 			pnv_idle_states[i].psscr_mask = temp_u64[i];
1399 	}
1400 
1401 	/*
1402 	 * power8 specific properties ibm,cpu-idle-state-pmicr-mask and
1403 	 * ibm,cpu-idle-state-pmicr-val were never used and there is no
1404 	 * plan to use it in near future. Hence, not parsing these properties
1405 	 */
1406 
1407 	if (of_property_read_string_array(np, "ibm,cpu-idle-state-names",
1408 					  temp_string, nr_idle_states) < 0) {
1409 		pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-names in DT\n");
1410 		rc = -EINVAL;
1411 		goto out;
1412 	}
1413 	for (i = 0; i < nr_idle_states; i++)
1414 		strlcpy(pnv_idle_states[i].name, temp_string[i],
1415 			PNV_IDLE_NAME_LEN);
1416 	nr_pnv_idle_states = nr_idle_states;
1417 	rc = 0;
1418 out:
1419 	kfree(temp_u32);
1420 	kfree(temp_u64);
1421 	kfree(temp_string);
1422 	return rc;
1423 }
1424 
1425 static int __init pnv_init_idle_states(void)
1426 {
1427 	int cpu;
1428 	int rc = 0;
1429 
1430 	/* Set up PACA fields */
1431 	for_each_present_cpu(cpu) {
1432 		struct paca_struct *p = paca_ptrs[cpu];
1433 
1434 		p->idle_state = 0;
1435 		if (cpu == cpu_first_thread_sibling(cpu))
1436 			p->idle_state = (1 << threads_per_core) - 1;
1437 
1438 		if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
1439 			/* P7/P8 nap */
1440 			p->thread_idle_state = PNV_THREAD_RUNNING;
1441 		} else if (pvr_version_is(PVR_POWER9)) {
1442 			/* P9 stop workarounds */
1443 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
1444 			p->requested_psscr = 0;
1445 			atomic_set(&p->dont_stop, 0);
1446 #endif
1447 		}
1448 	}
1449 
1450 	/* In case we error out nr_pnv_idle_states will be zero */
1451 	nr_pnv_idle_states = 0;
1452 	supported_cpuidle_states = 0;
1453 
1454 	if (cpuidle_disable != IDLE_NO_OVERRIDE)
1455 		goto out;
1456 	rc = pnv_parse_cpuidle_dt();
1457 	if (rc)
1458 		return rc;
1459 	pnv_probe_idle_states();
1460 
1461 	if (!cpu_has_feature(CPU_FTR_ARCH_300)) {
1462 		if (!(supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
1463 			power7_fastsleep_workaround_entry = false;
1464 			power7_fastsleep_workaround_exit = false;
1465 		} else {
1466 			/*
1467 			 * OPAL_PM_SLEEP_ENABLED_ER1 is set. It indicates that
1468 			 * workaround is needed to use fastsleep. Provide sysfs
1469 			 * control to choose how this workaround has to be
1470 			 * applied.
1471 			 */
1472 			device_create_file(cpu_subsys.dev_root,
1473 				&dev_attr_fastsleep_workaround_applyonce);
1474 		}
1475 
1476 		update_subcore_sibling_mask();
1477 
1478 		if (supported_cpuidle_states & OPAL_PM_NAP_ENABLED) {
1479 			ppc_md.power_save = power7_idle;
1480 			power7_offline_type = PNV_THREAD_NAP;
1481 		}
1482 
1483 		if ((supported_cpuidle_states & OPAL_PM_WINKLE_ENABLED) &&
1484 			   (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT))
1485 			power7_offline_type = PNV_THREAD_WINKLE;
1486 		else if ((supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED) ||
1487 			   (supported_cpuidle_states & OPAL_PM_SLEEP_ENABLED_ER1))
1488 			power7_offline_type = PNV_THREAD_SLEEP;
1489 	}
1490 
1491 	if (supported_cpuidle_states & OPAL_PM_LOSE_FULL_CONTEXT) {
1492 		if (pnv_save_sprs_for_deep_states())
1493 			pnv_disable_deep_states();
1494 	}
1495 
1496 out:
1497 	return 0;
1498 }
1499 machine_subsys_initcall(powernv, pnv_init_idle_states);
1500