4 * Copyright 2015 IBM Corp.
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/types.h>
14 #include <linux/slab.h>
16 #include <linux/device.h>
17 #include <linux/cpu.h>
19 #include <asm/firmware.h>
20 #include <asm/machdep.h>
22 #include <asm/cputhreads.h>
23 #include <asm/cpuidle.h>
24 #include <asm/code-patching.h>
26 #include <asm/runlatch.h>
31 /* Power ISA 3.0 allows for stop states 0x0 - 0xF */
32 #define MAX_STOP_STATE 0xF
34 #define P9_STOP_SPR_MSR 2000
35 #define P9_STOP_SPR_PSSCR 855
37 static u32 supported_cpuidle_states
;
40 * The default stop state that will be used by ppc_md.power_save
41 * function on platforms that support stop instruction.
43 static u64 pnv_default_stop_val
;
44 static u64 pnv_default_stop_mask
;
45 static bool default_stop_found
;
48 * First deep stop state. Used to figure out when to save/restore
51 u64 pnv_first_deep_stop_state
= MAX_STOP_STATE
;
54 * psscr value and mask of the deepest stop idle state.
55 * Used when a cpu is offlined.
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
;
62 static int pnv_save_sprs_for_deep_states(void)
68 * hid0, hid1, hid4, hid5, hmeer and lpcr values are symmetric across
69 * all cpus at boot. Get these reg values of current cpu and use the
70 * same across all cpus.
72 uint64_t lpcr_val
= mfspr(SPRN_LPCR
);
73 uint64_t hid0_val
= mfspr(SPRN_HID0
);
74 uint64_t hid1_val
= mfspr(SPRN_HID1
);
75 uint64_t hid4_val
= mfspr(SPRN_HID4
);
76 uint64_t hid5_val
= mfspr(SPRN_HID5
);
77 uint64_t hmeer_val
= mfspr(SPRN_HMEER
);
78 uint64_t msr_val
= MSR_IDLE
;
79 uint64_t psscr_val
= pnv_deepest_stop_psscr_val
;
81 for_each_possible_cpu(cpu
) {
82 uint64_t pir
= get_hard_smp_processor_id(cpu
);
83 uint64_t hsprg0_val
= (uint64_t)&paca
[cpu
];
85 rc
= opal_slw_set_reg(pir
, SPRN_HSPRG0
, hsprg0_val
);
89 rc
= opal_slw_set_reg(pir
, SPRN_LPCR
, lpcr_val
);
93 if (cpu_has_feature(CPU_FTR_ARCH_300
)) {
94 rc
= opal_slw_set_reg(pir
, P9_STOP_SPR_MSR
, msr_val
);
98 rc
= opal_slw_set_reg(pir
,
99 P9_STOP_SPR_PSSCR
, psscr_val
);
105 /* HIDs are per core registers */
106 if (cpu_thread_in_core(cpu
) == 0) {
108 rc
= opal_slw_set_reg(pir
, SPRN_HMEER
, hmeer_val
);
112 rc
= opal_slw_set_reg(pir
, SPRN_HID0
, hid0_val
);
116 /* Only p8 needs to set extra HID regiters */
117 if (!cpu_has_feature(CPU_FTR_ARCH_300
)) {
119 rc
= opal_slw_set_reg(pir
, SPRN_HID1
, hid1_val
);
123 rc
= opal_slw_set_reg(pir
, SPRN_HID4
, hid4_val
);
127 rc
= opal_slw_set_reg(pir
, SPRN_HID5
, hid5_val
);
137 static void pnv_alloc_idle_core_states(void)
140 int nr_cores
= cpu_nr_cores();
141 u32
*core_idle_state
;
144 * core_idle_state - The lower 8 bits track the idle state of
145 * each thread of the core.
147 * The most significant bit is the lock bit.
149 * Initially all the bits corresponding to threads_per_core
150 * are set. They are cleared when the thread enters deep idle
151 * state like sleep and winkle/stop.
153 * Initially the lock bit is cleared. The lock bit has 2
155 * a. While the first thread in the core waking up from
156 * idle is restoring core state, it prevents other
157 * threads in the core from switching to process
159 * b. While the last thread in the core is saving the
160 * core state, it prevents a different thread from
163 for (i
= 0; i
< nr_cores
; i
++) {
164 int first_cpu
= i
* threads_per_core
;
165 int node
= cpu_to_node(first_cpu
);
166 size_t paca_ptr_array_size
;
168 core_idle_state
= kmalloc_node(sizeof(u32
), GFP_KERNEL
, node
);
169 *core_idle_state
= (1 << threads_per_core
) - 1;
170 paca_ptr_array_size
= (threads_per_core
*
171 sizeof(struct paca_struct
*));
173 for (j
= 0; j
< threads_per_core
; j
++) {
174 int cpu
= first_cpu
+ j
;
176 paca
[cpu
].core_idle_state_ptr
= core_idle_state
;
177 paca
[cpu
].thread_idle_state
= PNV_THREAD_RUNNING
;
178 paca
[cpu
].thread_mask
= 1 << j
;
179 if (!cpu_has_feature(CPU_FTR_POWER9_DD1
))
181 paca
[cpu
].thread_sibling_pacas
=
182 kmalloc_node(paca_ptr_array_size
,
187 update_subcore_sibling_mask();
189 if (supported_cpuidle_states
& OPAL_PM_LOSE_FULL_CONTEXT
) {
190 int rc
= pnv_save_sprs_for_deep_states();
196 * The stop-api is unable to restore hypervisor
197 * resources on wakeup from platform idle states which
198 * lose full context. So disable such states.
200 supported_cpuidle_states
&= ~OPAL_PM_LOSE_FULL_CONTEXT
;
201 pr_warn("cpuidle-powernv: Disabling idle states that lose full context\n");
202 pr_warn("cpuidle-powernv: Idle power-savings, CPU-Hotplug affected\n");
204 if (cpu_has_feature(CPU_FTR_ARCH_300
) &&
205 (pnv_deepest_stop_flag
& OPAL_PM_LOSE_FULL_CONTEXT
)) {
207 * Use the default stop state for CPU-Hotplug
210 if (default_stop_found
) {
211 pnv_deepest_stop_psscr_val
=
212 pnv_default_stop_val
;
213 pnv_deepest_stop_psscr_mask
=
214 pnv_default_stop_mask
;
215 pr_warn("cpuidle-powernv: Offlined CPUs will stop with psscr = 0x%016llx\n",
216 pnv_deepest_stop_psscr_val
);
217 } else { /* Fallback to snooze loop for CPU-Hotplug */
218 deepest_stop_found
= false;
219 pr_warn("cpuidle-powernv: Offlined CPUs will busy wait\n");
225 u32
pnv_get_supported_cpuidle_states(void)
227 return supported_cpuidle_states
;
229 EXPORT_SYMBOL_GPL(pnv_get_supported_cpuidle_states
);
231 static void pnv_fastsleep_workaround_apply(void *info
)
237 rc
= opal_config_cpu_idle_state(OPAL_CONFIG_IDLE_FASTSLEEP
,
238 OPAL_CONFIG_IDLE_APPLY
);
244 * Used to store fastsleep workaround state
245 * 0 - Workaround applied/undone at fastsleep entry/exit path (Default)
246 * 1 - Workaround applied once, never undone.
248 static u8 fastsleep_workaround_applyonce
;
250 static ssize_t
show_fastsleep_workaround_applyonce(struct device
*dev
,
251 struct device_attribute
*attr
, char *buf
)
253 return sprintf(buf
, "%u\n", fastsleep_workaround_applyonce
);
256 static ssize_t
store_fastsleep_workaround_applyonce(struct device
*dev
,
257 struct device_attribute
*attr
, const char *buf
,
260 cpumask_t primary_thread_mask
;
264 if (kstrtou8(buf
, 0, &val
) || val
!= 1)
267 if (fastsleep_workaround_applyonce
== 1)
271 * fastsleep_workaround_applyonce = 1 implies
272 * fastsleep workaround needs to be left in 'applied' state on all
273 * the cores. Do this by-
274 * 1. Patching out the call to 'undo' workaround in fastsleep exit path
275 * 2. Sending ipi to all the cores which have at least one online thread
276 * 3. Patching out the call to 'apply' workaround in fastsleep entry
278 * There is no need to send ipi to cores which have all threads
279 * offlined, as last thread of the core entering fastsleep or deeper
280 * state would have applied workaround.
282 err
= patch_instruction(
283 (unsigned int *)pnv_fastsleep_workaround_at_exit
,
286 pr_err("fastsleep_workaround_applyonce change failed while patching pnv_fastsleep_workaround_at_exit");
291 primary_thread_mask
= cpu_online_cores_map();
292 on_each_cpu_mask(&primary_thread_mask
,
293 pnv_fastsleep_workaround_apply
,
297 pr_err("fastsleep_workaround_applyonce change failed while running pnv_fastsleep_workaround_apply");
301 err
= patch_instruction(
302 (unsigned int *)pnv_fastsleep_workaround_at_entry
,
305 pr_err("fastsleep_workaround_applyonce change failed while patching pnv_fastsleep_workaround_at_entry");
309 fastsleep_workaround_applyonce
= 1;
316 static DEVICE_ATTR(fastsleep_workaround_applyonce
, 0600,
317 show_fastsleep_workaround_applyonce
,
318 store_fastsleep_workaround_applyonce
);
320 static unsigned long __power7_idle_type(unsigned long type
)
324 if (!prep_irq_for_idle_irqsoff())
327 __ppc64_runlatch_off();
328 srr1
= power7_idle_insn(type
);
329 __ppc64_runlatch_on();
331 fini_irq_for_idle_irqsoff();
336 void power7_idle_type(unsigned long type
)
340 srr1
= __power7_idle_type(type
);
341 irq_set_pending_from_srr1(srr1
);
344 void power7_idle(void)
349 power7_idle_type(PNV_THREAD_NAP
);
352 static unsigned long __power9_idle_type(unsigned long stop_psscr_val
,
353 unsigned long stop_psscr_mask
)
358 if (!prep_irq_for_idle_irqsoff())
361 psscr
= mfspr(SPRN_PSSCR
);
362 psscr
= (psscr
& ~stop_psscr_mask
) | stop_psscr_val
;
364 __ppc64_runlatch_off();
365 srr1
= power9_idle_stop(psscr
);
366 __ppc64_runlatch_on();
368 fini_irq_for_idle_irqsoff();
373 void power9_idle_type(unsigned long stop_psscr_val
,
374 unsigned long stop_psscr_mask
)
378 srr1
= __power9_idle_type(stop_psscr_val
, stop_psscr_mask
);
379 irq_set_pending_from_srr1(srr1
);
383 * Used for ppc_md.power_save which needs a function with no parameters
385 void power9_idle(void)
387 power9_idle_type(pnv_default_stop_val
, pnv_default_stop_mask
);
390 #ifdef CONFIG_HOTPLUG_CPU
391 static void pnv_program_cpu_hotplug_lpcr(unsigned int cpu
, u64 lpcr_val
)
393 u64 pir
= get_hard_smp_processor_id(cpu
);
395 mtspr(SPRN_LPCR
, lpcr_val
);
396 opal_slw_set_reg(pir
, SPRN_LPCR
, lpcr_val
);
400 * pnv_cpu_offline: A function that puts the CPU into the deepest
401 * available platform idle state on a CPU-Offline.
402 * interrupts hard disabled and no lazy irq pending.
404 unsigned long pnv_cpu_offline(unsigned int cpu
)
407 u32 idle_states
= pnv_get_supported_cpuidle_states();
411 * We don't want to take decrementer interrupts while we are
412 * offline, so clear LPCR:PECE1. We keep PECE2 (and
413 * LPCR_PECE_HVEE on P9) enabled as to let IPIs in.
415 * If the CPU gets woken up by a special wakeup, ensure that
416 * the SLW engine sets LPCR with decrementer bit cleared, else
417 * the CPU will come back to the kernel due to a spurious
420 lpcr_val
= mfspr(SPRN_LPCR
) & ~(u64
)LPCR_PECE1
;
421 pnv_program_cpu_hotplug_lpcr(cpu
, lpcr_val
);
423 __ppc64_runlatch_off();
425 if (cpu_has_feature(CPU_FTR_ARCH_300
) && deepest_stop_found
) {
428 psscr
= mfspr(SPRN_PSSCR
);
429 psscr
= (psscr
& ~pnv_deepest_stop_psscr_mask
) |
430 pnv_deepest_stop_psscr_val
;
431 srr1
= power9_idle_stop(psscr
);
433 } else if ((idle_states
& OPAL_PM_WINKLE_ENABLED
) &&
434 (idle_states
& OPAL_PM_LOSE_FULL_CONTEXT
)) {
435 srr1
= power7_idle_insn(PNV_THREAD_WINKLE
);
436 } else if ((idle_states
& OPAL_PM_SLEEP_ENABLED
) ||
437 (idle_states
& OPAL_PM_SLEEP_ENABLED_ER1
)) {
438 srr1
= power7_idle_insn(PNV_THREAD_SLEEP
);
439 } else if (idle_states
& OPAL_PM_NAP_ENABLED
) {
440 srr1
= power7_idle_insn(PNV_THREAD_NAP
);
442 /* This is the fallback method. We emulate snooze */
443 while (!generic_check_cpu_restart(cpu
)) {
451 __ppc64_runlatch_on();
454 * Re-enable decrementer interrupts in LPCR.
456 * Further, we want stop states to be woken up by decrementer
457 * for non-hotplug cases. So program the LPCR via stop api as
460 lpcr_val
= mfspr(SPRN_LPCR
) | (u64
)LPCR_PECE1
;
461 pnv_program_cpu_hotplug_lpcr(cpu
, lpcr_val
);
468 * Power ISA 3.0 idle initialization.
470 * POWER ISA 3.0 defines a new SPR Processor stop Status and Control
471 * Register (PSSCR) to control idle behavior.
474 * ----------------------------------------------------------
475 * | PLS | /// | SD | ESL | EC | PSLL | /// | TR | MTL | RL |
476 * ----------------------------------------------------------
477 * 0 4 41 42 43 44 48 54 56 60
480 * Bits 0:3 - Power-Saving Level Status (PLS). This field indicates the
481 * lowest power-saving state the thread entered since stop instruction was
484 * Bit 41 - Status Disable(SD)
485 * 0 - Shows PLS entries
486 * 1 - PLS entries are all 0
488 * Bit 42 - Enable State Loss
489 * 0 - No state is lost irrespective of other fields
490 * 1 - Allows state loss
492 * Bit 43 - Exit Criterion
493 * 0 - Exit from power-save mode on any interrupt
494 * 1 - Exit from power-save mode controlled by LPCR's PECE bits
496 * Bits 44:47 - Power-Saving Level Limit
497 * This limits the power-saving level that can be entered into.
499 * Bits 60:63 - Requested Level
500 * Used to specify which power-saving level must be entered on executing
504 int validate_psscr_val_mask(u64
*psscr_val
, u64
*psscr_mask
, u32 flags
)
509 * psscr_mask == 0xf indicates an older firmware.
510 * Set remaining fields of psscr to the default values.
511 * See NOTE above definition of PSSCR_HV_DEFAULT_VAL
513 if (*psscr_mask
== 0xf) {
514 *psscr_val
= *psscr_val
| PSSCR_HV_DEFAULT_VAL
;
515 *psscr_mask
= PSSCR_HV_DEFAULT_MASK
;
520 * New firmware is expected to set the psscr_val bits correctly.
521 * Validate that the following invariants are correctly maintained by
523 * - ESL bit value matches the EC bit value.
524 * - ESL bit is set for all the deep stop states.
526 if (GET_PSSCR_ESL(*psscr_val
) != GET_PSSCR_EC(*psscr_val
)) {
527 err
= ERR_EC_ESL_MISMATCH
;
528 } else if ((flags
& OPAL_PM_LOSE_FULL_CONTEXT
) &&
529 GET_PSSCR_ESL(*psscr_val
) == 0) {
530 err
= ERR_DEEP_STATE_ESL_MISMATCH
;
537 * pnv_arch300_idle_init: Initializes the default idle state, first
538 * deep idle state and deepest idle state on
541 * @np: /ibm,opal/power-mgt device node
542 * @flags: cpu-idle-state-flags array
543 * @dt_idle_states: Number of idle state entries
544 * Returns 0 on success
546 static int __init
pnv_power9_idle_init(struct device_node
*np
, u32
*flags
,
549 u64
*psscr_val
= NULL
;
550 u64
*psscr_mask
= NULL
;
551 u32
*residency_ns
= NULL
;
552 u64 max_residency_ns
= 0;
555 psscr_val
= kcalloc(dt_idle_states
, sizeof(*psscr_val
), GFP_KERNEL
);
556 psscr_mask
= kcalloc(dt_idle_states
, sizeof(*psscr_mask
), GFP_KERNEL
);
557 residency_ns
= kcalloc(dt_idle_states
, sizeof(*residency_ns
),
560 if (!psscr_val
|| !psscr_mask
|| !residency_ns
) {
565 if (of_property_read_u64_array(np
,
566 "ibm,cpu-idle-state-psscr",
567 psscr_val
, dt_idle_states
)) {
568 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr in DT\n");
573 if (of_property_read_u64_array(np
,
574 "ibm,cpu-idle-state-psscr-mask",
575 psscr_mask
, dt_idle_states
)) {
576 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-psscr-mask in DT\n");
581 if (of_property_read_u32_array(np
,
582 "ibm,cpu-idle-state-residency-ns",
583 residency_ns
, dt_idle_states
)) {
584 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-residency-ns in DT\n");
590 * Set pnv_first_deep_stop_state, pnv_deepest_stop_psscr_{val,mask},
591 * and the pnv_default_stop_{val,mask}.
593 * pnv_first_deep_stop_state should be set to the first stop
594 * level to cause hypervisor state loss.
596 * pnv_deepest_stop_{val,mask} should be set to values corresponding to
597 * the deepest stop state.
599 * pnv_default_stop_{val,mask} should be set to values corresponding to
600 * the shallowest (OPAL_PM_STOP_INST_FAST) loss-less stop state.
602 pnv_first_deep_stop_state
= MAX_STOP_STATE
;
603 for (i
= 0; i
< dt_idle_states
; i
++) {
605 u64 psscr_rl
= psscr_val
[i
] & PSSCR_RL_MASK
;
607 if ((flags
[i
] & OPAL_PM_LOSE_FULL_CONTEXT
) &&
608 (pnv_first_deep_stop_state
> psscr_rl
))
609 pnv_first_deep_stop_state
= psscr_rl
;
611 err
= validate_psscr_val_mask(&psscr_val
[i
], &psscr_mask
[i
],
614 report_invalid_psscr_val(psscr_val
[i
], err
);
618 if (max_residency_ns
< residency_ns
[i
]) {
619 max_residency_ns
= residency_ns
[i
];
620 pnv_deepest_stop_psscr_val
= psscr_val
[i
];
621 pnv_deepest_stop_psscr_mask
= psscr_mask
[i
];
622 pnv_deepest_stop_flag
= flags
[i
];
623 deepest_stop_found
= true;
626 if (!default_stop_found
&&
627 (flags
[i
] & OPAL_PM_STOP_INST_FAST
)) {
628 pnv_default_stop_val
= psscr_val
[i
];
629 pnv_default_stop_mask
= psscr_mask
[i
];
630 default_stop_found
= true;
634 if (unlikely(!default_stop_found
)) {
635 pr_warn("cpuidle-powernv: No suitable default stop state found. Disabling platform idle.\n");
637 ppc_md
.power_save
= power9_idle
;
638 pr_info("cpuidle-powernv: Default stop: psscr = 0x%016llx,mask=0x%016llx\n",
639 pnv_default_stop_val
, pnv_default_stop_mask
);
642 if (unlikely(!deepest_stop_found
)) {
643 pr_warn("cpuidle-powernv: No suitable stop state for CPU-Hotplug. Offlined CPUs will busy wait");
645 pr_info("cpuidle-powernv: Deepest stop: psscr = 0x%016llx,mask=0x%016llx\n",
646 pnv_deepest_stop_psscr_val
,
647 pnv_deepest_stop_psscr_mask
);
650 pr_info("cpuidle-powernv: Requested Level (RL) value of first deep stop = 0x%llx\n",
651 pnv_first_deep_stop_state
);
660 * Probe device tree for supported idle states
662 static void __init
pnv_probe_idle_states(void)
664 struct device_node
*np
;
669 np
= of_find_node_by_path("/ibm,opal/power-mgt");
671 pr_warn("opal: PowerMgmt Node not found\n");
674 dt_idle_states
= of_property_count_u32_elems(np
,
675 "ibm,cpu-idle-state-flags");
676 if (dt_idle_states
< 0) {
677 pr_warn("cpuidle-powernv: no idle states found in the DT\n");
681 flags
= kcalloc(dt_idle_states
, sizeof(*flags
), GFP_KERNEL
);
683 if (of_property_read_u32_array(np
,
684 "ibm,cpu-idle-state-flags", flags
, dt_idle_states
)) {
685 pr_warn("cpuidle-powernv: missing ibm,cpu-idle-state-flags in DT\n");
689 if (cpu_has_feature(CPU_FTR_ARCH_300
)) {
690 if (pnv_power9_idle_init(np
, flags
, dt_idle_states
))
694 for (i
= 0; i
< dt_idle_states
; i
++)
695 supported_cpuidle_states
|= flags
[i
];
700 static int __init
pnv_init_idle_states(void)
703 supported_cpuidle_states
= 0;
705 if (cpuidle_disable
!= IDLE_NO_OVERRIDE
)
708 pnv_probe_idle_states();
710 if (!(supported_cpuidle_states
& OPAL_PM_SLEEP_ENABLED_ER1
)) {
712 (unsigned int *)pnv_fastsleep_workaround_at_entry
,
715 (unsigned int *)pnv_fastsleep_workaround_at_exit
,
719 * OPAL_PM_SLEEP_ENABLED_ER1 is set. It indicates that
720 * workaround is needed to use fastsleep. Provide sysfs
721 * control to choose how this workaround has to be applied.
723 device_create_file(cpu_subsys
.dev_root
,
724 &dev_attr_fastsleep_workaround_applyonce
);
727 pnv_alloc_idle_core_states();
730 * For each CPU, record its PACA address in each of it's
731 * sibling thread's PACA at the slot corresponding to this
732 * CPU's index in the core.
734 if (cpu_has_feature(CPU_FTR_POWER9_DD1
)) {
737 pr_info("powernv: idle: Saving PACA pointers of all CPUs in their thread sibling PACA\n");
738 for_each_possible_cpu(cpu
) {
739 int base_cpu
= cpu_first_thread_sibling(cpu
);
740 int idx
= cpu_thread_in_core(cpu
);
743 for (i
= 0; i
< threads_per_core
; i
++) {
744 int j
= base_cpu
+ i
;
746 paca
[j
].thread_sibling_pacas
[idx
] = &paca
[cpu
];
751 if (supported_cpuidle_states
& OPAL_PM_NAP_ENABLED
)
752 ppc_md
.power_save
= power7_idle
;
757 machine_subsys_initcall(powernv
, pnv_init_idle_states
);