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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
707827f3 | 2 | /* |
962e7bd4 | 3 | * cpuidle-pseries - idle state cpuidle driver. |
707827f3 DD |
4 | * Adapted from drivers/idle/intel_idle.c and |
5 | * drivers/acpi/processor_idle.c | |
6 | * | |
7 | */ | |
8 | ||
9 | #include <linux/kernel.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/moduleparam.h> | |
13 | #include <linux/cpuidle.h> | |
14 | #include <linux/cpu.h> | |
16aaaff6 | 15 | #include <linux/notifier.h> |
707827f3 DD |
16 | |
17 | #include <asm/paca.h> | |
18 | #include <asm/reg.h> | |
707827f3 DD |
19 | #include <asm/machdep.h> |
20 | #include <asm/firmware.h> | |
3f67d962 | 21 | #include <asm/runlatch.h> |
e4a884cc | 22 | #include <asm/idle.h> |
212bebb4 | 23 | #include <asm/plpar_wrappers.h> |
054e44ba | 24 | #include <asm/rtas.h> |
707827f3 | 25 | |
92fe8483 | 26 | static struct cpuidle_driver pseries_idle_driver = { |
1ca80944 DL |
27 | .name = "pseries_idle", |
28 | .owner = THIS_MODULE, | |
707827f3 DD |
29 | }; |
30 | ||
624e46d0 NP |
31 | static int max_idle_state __read_mostly; |
32 | static struct cpuidle_state *cpuidle_state_table __read_mostly; | |
33 | static u64 snooze_timeout __read_mostly; | |
34 | static bool snooze_timeout_en __read_mostly; | |
707827f3 | 35 | |
88990745 ME |
36 | static __cpuidle |
37 | int snooze_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
38 | int index) | |
707827f3 | 39 | { |
78eaa10f | 40 | u64 snooze_exit_time; |
707827f3 | 41 | |
3fc5ee92 NP |
42 | set_thread_flag(TIF_POLLING_NRFLAG); |
43 | ||
c4019198 | 44 | pseries_idle_prolog(); |
88990745 | 45 | raw_local_irq_enable(); |
78eaa10f | 46 | snooze_exit_time = get_tb() + snooze_timeout; |
5ddcc03a | 47 | dev->poll_time_limit = false; |
707827f3 | 48 | |
b69dbba0 | 49 | while (!need_resched()) { |
83dac594 DD |
50 | HMT_low(); |
51 | HMT_very_low(); | |
7ded4291 NP |
52 | if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) { |
53 | /* | |
54 | * Task has not woken up but we are exiting the polling | |
55 | * loop anyway. Require a barrier after polling is | |
56 | * cleared to order subsequent test of need_resched(). | |
57 | */ | |
5ddcc03a | 58 | dev->poll_time_limit = true; |
7ded4291 NP |
59 | clear_thread_flag(TIF_POLLING_NRFLAG); |
60 | smp_mb(); | |
78eaa10f | 61 | break; |
7ded4291 | 62 | } |
707827f3 DD |
63 | } |
64 | ||
707827f3 | 65 | HMT_medium(); |
83dac594 | 66 | clear_thread_flag(TIF_POLLING_NRFLAG); |
83dac594 | 67 | |
88990745 | 68 | raw_local_irq_disable(); |
ced54c08 | 69 | |
c4019198 | 70 | pseries_idle_epilog(); |
1ca80944 | 71 | |
707827f3 DD |
72 | return index; |
73 | } | |
74 | ||
88990745 | 75 | static __cpuidle void check_and_cede_processor(void) |
7230c564 BH |
76 | { |
77 | /* | |
be2cf20a BH |
78 | * Ensure our interrupt state is properly tracked, |
79 | * also checks if no interrupt has occurred while we | |
80 | * were soft-disabled | |
7230c564 | 81 | */ |
be2cf20a | 82 | if (prep_irq_for_idle()) { |
7230c564 | 83 | cede_processor(); |
be2cf20a BH |
84 | #ifdef CONFIG_TRACE_IRQFLAGS |
85 | /* Ensure that H_CEDE returns with IRQs on */ | |
86 | if (WARN_ON(!(mfmsr() & MSR_EE))) | |
87 | __hard_irq_enable(); | |
88 | #endif | |
89 | } | |
7230c564 BH |
90 | } |
91 | ||
054e44ba GS |
92 | /* |
93 | * XCEDE: Extended CEDE states discovered through the | |
94 | * "ibm,get-systems-parameter" RTAS call with the token | |
95 | * CEDE_LATENCY_TOKEN | |
96 | */ | |
97 | ||
98 | /* | |
99 | * Section 7.3.16 System Parameters Option of PAPR version 2.8.1 has a | |
100 | * table with all the parameters to ibm,get-system-parameters. | |
101 | * CEDE_LATENCY_TOKEN corresponds to the token value for Cede Latency | |
102 | * Settings Information. | |
103 | */ | |
104 | #define CEDE_LATENCY_TOKEN 45 | |
105 | ||
106 | /* | |
107 | * If the platform supports the cede latency settings information system | |
108 | * parameter it must provide the following information in the NULL terminated | |
109 | * parameter string: | |
110 | * | |
111 | * a. The first byte is the length āNā of each cede latency setting record minus | |
112 | * one (zero indicates a length of 1 byte). | |
113 | * | |
114 | * b. For each supported cede latency setting a cede latency setting record | |
115 | * consisting of the first āNā bytes as per the following table. | |
116 | * | |
117 | * ----------------------------- | |
118 | * | Field | Field | | |
119 | * | Name | Length | | |
120 | * ----------------------------- | |
121 | * | Cede Latency | 1 Byte | | |
122 | * | Specifier Value | | | |
123 | * ----------------------------- | |
124 | * | Maximum wakeup | | | |
125 | * | latency in | 8 Bytes | | |
126 | * | tb-ticks | | | |
127 | * ----------------------------- | |
128 | * | Responsive to | | | |
129 | * | external | 1 Byte | | |
130 | * | interrupts | | | |
131 | * ----------------------------- | |
132 | * | |
133 | * This version has cede latency record size = 10. | |
134 | * | |
135 | * The structure xcede_latency_payload represents a) and b) with | |
136 | * xcede_latency_record representing the table in b). | |
137 | * | |
138 | * xcede_latency_parameter is what gets returned by | |
139 | * ibm,get-systems-parameter RTAS call when made with | |
140 | * CEDE_LATENCY_TOKEN. | |
141 | * | |
142 | * These structures are only used to represent the data obtained by the RTAS | |
143 | * call. The data is in big-endian. | |
144 | */ | |
145 | struct xcede_latency_record { | |
146 | u8 hint; | |
147 | __be64 latency_ticks; | |
148 | u8 wake_on_irqs; | |
149 | } __packed; | |
150 | ||
151 | // Make space for 16 records, which "should be enough". | |
152 | struct xcede_latency_payload { | |
153 | u8 record_size; | |
154 | struct xcede_latency_record records[16]; | |
155 | } __packed; | |
156 | ||
157 | struct xcede_latency_parameter { | |
158 | __be16 payload_size; | |
159 | struct xcede_latency_payload payload; | |
160 | u8 null_char; | |
161 | } __packed; | |
162 | ||
163 | static unsigned int nr_xcede_records; | |
164 | static struct xcede_latency_parameter xcede_latency_parameter __initdata; | |
165 | ||
166 | static int __init parse_cede_parameters(void) | |
167 | { | |
168 | struct xcede_latency_payload *payload; | |
169 | u32 total_xcede_records_size; | |
170 | u8 xcede_record_size; | |
171 | u16 payload_size; | |
172 | int ret, i; | |
173 | ||
174 | ret = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1, | |
175 | NULL, CEDE_LATENCY_TOKEN, __pa(&xcede_latency_parameter), | |
176 | sizeof(xcede_latency_parameter)); | |
177 | if (ret) { | |
178 | pr_err("xcede: Error parsing CEDE_LATENCY_TOKEN\n"); | |
179 | return ret; | |
180 | } | |
181 | ||
182 | payload_size = be16_to_cpu(xcede_latency_parameter.payload_size); | |
183 | payload = &xcede_latency_parameter.payload; | |
3af0ada7 | 184 | |
054e44ba GS |
185 | xcede_record_size = payload->record_size + 1; |
186 | ||
187 | if (xcede_record_size != sizeof(struct xcede_latency_record)) { | |
188 | pr_err("xcede: Expected record-size %lu. Observed size %u.\n", | |
189 | sizeof(struct xcede_latency_record), xcede_record_size); | |
190 | return -EINVAL; | |
191 | } | |
192 | ||
193 | pr_info("xcede: xcede_record_size = %d\n", xcede_record_size); | |
194 | ||
195 | /* | |
196 | * Since the payload_size includes the last NULL byte and the | |
197 | * xcede_record_size, the remaining bytes correspond to array of all | |
198 | * cede_latency settings. | |
199 | */ | |
200 | total_xcede_records_size = payload_size - 2; | |
201 | nr_xcede_records = total_xcede_records_size / xcede_record_size; | |
202 | ||
203 | for (i = 0; i < nr_xcede_records; i++) { | |
204 | struct xcede_latency_record *record = &payload->records[i]; | |
205 | u64 latency_ticks = be64_to_cpu(record->latency_ticks); | |
206 | u8 wake_on_irqs = record->wake_on_irqs; | |
207 | u8 hint = record->hint; | |
208 | ||
209 | pr_info("xcede: Record %d : hint = %u, latency = 0x%llx tb ticks, Wake-on-irq = %u\n", | |
210 | i, hint, latency_ticks, wake_on_irqs); | |
211 | } | |
212 | ||
213 | return 0; | |
214 | } | |
215 | ||
216 | #define NR_DEDICATED_STATES 2 /* snooze, CEDE */ | |
3af0ada7 GS |
217 | static u8 cede_latency_hint[NR_DEDICATED_STATES]; |
218 | ||
88990745 ME |
219 | static __cpuidle |
220 | int dedicated_cede_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
221 | int index) | |
707827f3 | 222 | { |
3af0ada7 | 223 | u8 old_latency_hint; |
707827f3 | 224 | |
c4019198 | 225 | pseries_idle_prolog(); |
707827f3 | 226 | get_lppaca()->donate_dedicated_cpu = 1; |
3af0ada7 GS |
227 | old_latency_hint = get_lppaca()->cede_latency_hint; |
228 | get_lppaca()->cede_latency_hint = cede_latency_hint[index]; | |
707827f3 | 229 | |
707827f3 | 230 | HMT_medium(); |
7230c564 | 231 | check_and_cede_processor(); |
707827f3 | 232 | |
88990745 | 233 | raw_local_irq_disable(); |
707827f3 | 234 | get_lppaca()->donate_dedicated_cpu = 0; |
3af0ada7 | 235 | get_lppaca()->cede_latency_hint = old_latency_hint; |
1ca80944 | 236 | |
c4019198 | 237 | pseries_idle_epilog(); |
1ca80944 | 238 | |
707827f3 DD |
239 | return index; |
240 | } | |
241 | ||
88990745 ME |
242 | static __cpuidle |
243 | int shared_cede_loop(struct cpuidle_device *dev, struct cpuidle_driver *drv, | |
244 | int index) | |
707827f3 | 245 | { |
707827f3 | 246 | |
c4019198 | 247 | pseries_idle_prolog(); |
707827f3 DD |
248 | |
249 | /* | |
250 | * Yield the processor to the hypervisor. We return if | |
251 | * an external interrupt occurs (which are driven prior | |
252 | * to returning here) or if a prod occurs from another | |
253 | * processor. When returning here, external interrupts | |
254 | * are enabled. | |
255 | */ | |
7230c564 | 256 | check_and_cede_processor(); |
707827f3 | 257 | |
88990745 | 258 | raw_local_irq_disable(); |
c4019198 | 259 | pseries_idle_epilog(); |
1ca80944 | 260 | |
707827f3 DD |
261 | return index; |
262 | } | |
263 | ||
264 | /* | |
265 | * States for dedicated partition case. | |
266 | */ | |
3af0ada7 | 267 | static struct cpuidle_state dedicated_states[NR_DEDICATED_STATES] = { |
707827f3 DD |
268 | { /* Snooze */ |
269 | .name = "snooze", | |
270 | .desc = "snooze", | |
707827f3 DD |
271 | .exit_latency = 0, |
272 | .target_residency = 0, | |
5ddcc03a AD |
273 | .enter = &snooze_loop, |
274 | .flags = CPUIDLE_FLAG_POLLING }, | |
707827f3 DD |
275 | { /* CEDE */ |
276 | .name = "CEDE", | |
277 | .desc = "CEDE", | |
83dac594 DD |
278 | .exit_latency = 10, |
279 | .target_residency = 100, | |
707827f3 DD |
280 | .enter = &dedicated_cede_loop }, |
281 | }; | |
282 | ||
283 | /* | |
284 | * States for shared partition case. | |
285 | */ | |
bf7f61f2 | 286 | static struct cpuidle_state shared_states[] = { |
f2ac428e NP |
287 | { /* Snooze */ |
288 | .name = "snooze", | |
289 | .desc = "snooze", | |
290 | .exit_latency = 0, | |
291 | .target_residency = 0, | |
5ddcc03a AD |
292 | .enter = &snooze_loop, |
293 | .flags = CPUIDLE_FLAG_POLLING }, | |
707827f3 DD |
294 | { /* Shared Cede */ |
295 | .name = "Shared Cede", | |
296 | .desc = "Shared Cede", | |
f2ac428e NP |
297 | .exit_latency = 10, |
298 | .target_residency = 100, | |
707827f3 DD |
299 | .enter = &shared_cede_loop }, |
300 | }; | |
301 | ||
529351fd | 302 | static int pseries_cpuidle_cpu_online(unsigned int cpu) |
707827f3 | 303 | { |
529351fd | 304 | struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); |
16aaaff6 | 305 | |
852d8cb1 | 306 | if (dev && cpuidle_get_driver()) { |
529351fd SAS |
307 | cpuidle_pause_and_lock(); |
308 | cpuidle_enable_device(dev); | |
309 | cpuidle_resume_and_unlock(); | |
310 | } | |
311 | return 0; | |
312 | } | |
852d8cb1 | 313 | |
529351fd SAS |
314 | static int pseries_cpuidle_cpu_dead(unsigned int cpu) |
315 | { | |
316 | struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); | |
852d8cb1 | 317 | |
529351fd SAS |
318 | if (dev && cpuidle_get_driver()) { |
319 | cpuidle_pause_and_lock(); | |
320 | cpuidle_disable_device(dev); | |
321 | cpuidle_resume_and_unlock(); | |
707827f3 | 322 | } |
529351fd | 323 | return 0; |
707827f3 DD |
324 | } |
325 | ||
326 | /* | |
327 | * pseries_cpuidle_driver_init() | |
328 | */ | |
329 | static int pseries_cpuidle_driver_init(void) | |
330 | { | |
331 | int idle_state; | |
332 | struct cpuidle_driver *drv = &pseries_idle_driver; | |
333 | ||
334 | drv->state_count = 0; | |
335 | ||
bf7f61f2 DD |
336 | for (idle_state = 0; idle_state < max_idle_state; ++idle_state) { |
337 | /* Is the state not enabled? */ | |
707827f3 DD |
338 | if (cpuidle_state_table[idle_state].enter == NULL) |
339 | continue; | |
340 | ||
341 | drv->states[drv->state_count] = /* structure copy */ | |
342 | cpuidle_state_table[idle_state]; | |
343 | ||
707827f3 DD |
344 | drv->state_count += 1; |
345 | } | |
346 | ||
347 | return 0; | |
348 | } | |
349 | ||
d947fb4c | 350 | static void __init fixup_cede0_latency(void) |
054e44ba | 351 | { |
d947fb4c | 352 | struct xcede_latency_payload *payload; |
71737a6c | 353 | u64 min_xcede_latency_us = UINT_MAX; |
d947fb4c GS |
354 | int i; |
355 | ||
054e44ba GS |
356 | if (parse_cede_parameters()) |
357 | return; | |
358 | ||
d947fb4c | 359 | pr_info("cpuidle: Skipping the %d Extended CEDE idle states\n", |
054e44ba | 360 | nr_xcede_records); |
d947fb4c GS |
361 | |
362 | payload = &xcede_latency_parameter.payload; | |
71737a6c GS |
363 | |
364 | /* | |
365 | * The CEDE idle state maps to CEDE(0). While the hypervisor | |
366 | * does not advertise CEDE(0) exit latency values, it does | |
367 | * advertise the latency values of the extended CEDE states. | |
368 | * We use the lowest advertised exit latency value as a proxy | |
369 | * for the exit latency of CEDE(0). | |
370 | */ | |
d947fb4c GS |
371 | for (i = 0; i < nr_xcede_records; i++) { |
372 | struct xcede_latency_record *record = &payload->records[i]; | |
71737a6c | 373 | u8 hint = record->hint; |
d947fb4c | 374 | u64 latency_tb = be64_to_cpu(record->latency_ticks); |
1d3ee7df GS |
375 | u64 latency_us = DIV_ROUND_UP_ULL(tb_to_ns(latency_tb), NSEC_PER_USEC); |
376 | ||
1d3ee7df | 377 | /* |
71737a6c GS |
378 | * We expect the exit latency of an extended CEDE |
379 | * state to be non-zero, it to since it takes at least | |
380 | * a few nanoseconds to wakeup the idle CPU and | |
381 | * dispatch the virtual processor into the Linux | |
382 | * Guest. | |
383 | * | |
384 | * So we consider only non-zero value for performing | |
385 | * the fixup of CEDE(0) latency. | |
1d3ee7df | 386 | */ |
71737a6c GS |
387 | if (latency_us == 0) { |
388 | pr_warn("cpuidle: Skipping xcede record %d [hint=%d]. Exit latency = 0us\n", | |
389 | i, hint); | |
390 | continue; | |
391 | } | |
d947fb4c | 392 | |
71737a6c GS |
393 | if (latency_us < min_xcede_latency_us) |
394 | min_xcede_latency_us = latency_us; | |
395 | } | |
d947fb4c | 396 | |
71737a6c GS |
397 | if (min_xcede_latency_us != UINT_MAX) { |
398 | dedicated_states[1].exit_latency = min_xcede_latency_us; | |
399 | dedicated_states[1].target_residency = 10 * (min_xcede_latency_us); | |
d947fb4c | 400 | pr_info("cpuidle: Fixed up CEDE exit latency to %llu us\n", |
71737a6c | 401 | min_xcede_latency_us); |
d947fb4c GS |
402 | } |
403 | ||
054e44ba GS |
404 | } |
405 | ||
707827f3 DD |
406 | /* |
407 | * pseries_idle_probe() | |
408 | * Choose state table for shared versus dedicated partition | |
409 | */ | |
d04691d3 | 410 | static int __init pseries_idle_probe(void) |
707827f3 DD |
411 | { |
412 | ||
e8bb3e00 DD |
413 | if (cpuidle_disable != IDLE_NO_OVERRIDE) |
414 | return -ENODEV; | |
415 | ||
b69dbba0 | 416 | if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
eac030b2 | 417 | if (lppaca_shared_proc()) { |
b69dbba0 | 418 | cpuidle_state_table = shared_states; |
bf7f61f2 DD |
419 | max_idle_state = ARRAY_SIZE(shared_states); |
420 | } else { | |
50741b70 GS |
421 | /* |
422 | * Use firmware provided latency values | |
423 | * starting with POWER10 platforms. In the | |
424 | * case that we are running on a POWER10 | |
425 | * platform but in an earlier compat mode, we | |
426 | * can still use the firmware provided values. | |
427 | * | |
428 | * However, on platforms prior to POWER10, we | |
429 | * cannot rely on the accuracy of the firmware | |
430 | * provided latency values. On such platforms, | |
431 | * go with the conservative default estimate | |
432 | * of 10us. | |
433 | */ | |
434 | if (cpu_has_feature(CPU_FTR_ARCH_31) || pvr_version_is(PVR_POWER10)) | |
435 | fixup_cede0_latency(); | |
b69dbba0 | 436 | cpuidle_state_table = dedicated_states; |
3af0ada7 | 437 | max_idle_state = NR_DEDICATED_STATES; |
bf7f61f2 | 438 | } |
b69dbba0 DD |
439 | } else |
440 | return -ENODEV; | |
707827f3 | 441 | |
78eaa10f SB |
442 | if (max_idle_state > 1) { |
443 | snooze_timeout_en = true; | |
444 | snooze_timeout = cpuidle_state_table[1].target_residency * | |
445 | tb_ticks_per_usec; | |
446 | } | |
707827f3 DD |
447 | return 0; |
448 | } | |
449 | ||
450 | static int __init pseries_processor_idle_init(void) | |
451 | { | |
452 | int retval; | |
453 | ||
454 | retval = pseries_idle_probe(); | |
455 | if (retval) | |
456 | return retval; | |
457 | ||
458 | pseries_cpuidle_driver_init(); | |
b69dbba0 | 459 | retval = cpuidle_register(&pseries_idle_driver, NULL); |
707827f3 DD |
460 | if (retval) { |
461 | printk(KERN_DEBUG "Registration of pseries driver failed.\n"); | |
462 | return retval; | |
463 | } | |
464 | ||
529351fd SAS |
465 | retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, |
466 | "cpuidle/pseries:online", | |
467 | pseries_cpuidle_cpu_online, NULL); | |
468 | WARN_ON(retval < 0); | |
469 | retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD, | |
470 | "cpuidle/pseries:DEAD", NULL, | |
471 | pseries_cpuidle_cpu_dead); | |
472 | WARN_ON(retval < 0); | |
707827f3 | 473 | printk(KERN_DEBUG "pseries_idle_driver registered\n"); |
707827f3 DD |
474 | return 0; |
475 | } | |
476 | ||
12431c64 | 477 | device_initcall(pseries_processor_idle_init); |