blob: b76848c80be34729c56bd20d04f75f9f534cbb36 [file] [log] [blame]
Shaohua Li8e0af512009-07-27 18:11:02 -04001/*
2 * acpi_pad.c ACPI Processor Aggregator Driver
3 *
4 * Copyright (c) 2009, Intel Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 */
20
21#include <linux/kernel.h>
22#include <linux/cpumask.h>
23#include <linux/module.h>
24#include <linux/init.h>
25#include <linux/types.h>
26#include <linux/kthread.h>
27#include <linux/freezer.h>
28#include <linux/cpu.h>
29#include <linux/clockchips.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090030#include <linux/slab.h>
Shaohua Li8e0af512009-07-27 18:11:02 -040031#include <acpi/acpi_bus.h>
32#include <acpi/acpi_drivers.h>
33
Dan Carpentera40770a2010-04-27 14:06:05 -070034#define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
Shaohua Li8e0af512009-07-27 18:11:02 -040035#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
36#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
37static DEFINE_MUTEX(isolated_cpus_lock);
38
39#define MWAIT_SUBSTATE_MASK (0xf)
40#define MWAIT_CSTATE_MASK (0xf)
41#define MWAIT_SUBSTATE_SIZE (4)
42#define CPUID_MWAIT_LEAF (5)
43#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1)
44#define CPUID5_ECX_INTERRUPT_BREAK (0x2)
45static unsigned long power_saving_mwait_eax;
Venkatesh Pallipadi0dc698b2010-05-18 14:39:16 -070046
47static unsigned char tsc_detected_unstable;
48static unsigned char tsc_marked_unstable;
Chen Gong8aa4b142010-05-30 11:37:08 +080049static unsigned char lapic_detected_unstable;
50static unsigned char lapic_marked_unstable;
Venkatesh Pallipadi0dc698b2010-05-18 14:39:16 -070051
Shaohua Li8e0af512009-07-27 18:11:02 -040052static void power_saving_mwait_init(void)
53{
54 unsigned int eax, ebx, ecx, edx;
55 unsigned int highest_cstate = 0;
56 unsigned int highest_subcstate = 0;
57 int i;
58
59 if (!boot_cpu_has(X86_FEATURE_MWAIT))
60 return;
61 if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
62 return;
63
64 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
65
66 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
67 !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
68 return;
69
70 edx >>= MWAIT_SUBSTATE_SIZE;
71 for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
72 if (edx & MWAIT_SUBSTATE_MASK) {
73 highest_cstate = i;
74 highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
75 }
76 }
77 power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
78 (highest_subcstate - 1);
79
John Stultz592913e2010-07-13 17:56:20 -070080#if defined(CONFIG_X86)
Shaohua Li8e0af512009-07-27 18:11:02 -040081 switch (boot_cpu_data.x86_vendor) {
82 case X86_VENDOR_AMD:
83 case X86_VENDOR_INTEL:
84 /*
85 * AMD Fam10h TSC will tick in all
86 * C/P/S0/S1 states when this bit is set.
87 */
Chen Gong8aa4b142010-05-30 11:37:08 +080088 if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
89 tsc_detected_unstable = 1;
90 if (!boot_cpu_has(X86_FEATURE_ARAT))
91 lapic_detected_unstable = 1;
92 break;
Shaohua Li8e0af512009-07-27 18:11:02 -040093 default:
Chen Gong8aa4b142010-05-30 11:37:08 +080094 /* TSC & LAPIC could halt in idle */
Venkatesh Pallipadi0dc698b2010-05-18 14:39:16 -070095 tsc_detected_unstable = 1;
Chen Gong8aa4b142010-05-30 11:37:08 +080096 lapic_detected_unstable = 1;
Shaohua Li8e0af512009-07-27 18:11:02 -040097 }
98#endif
99}
100
101static unsigned long cpu_weight[NR_CPUS];
102static int tsk_in_cpu[NR_CPUS] = {[0 ... NR_CPUS-1] = -1};
103static DECLARE_BITMAP(pad_busy_cpus_bits, NR_CPUS);
104static void round_robin_cpu(unsigned int tsk_index)
105{
106 struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
107 cpumask_var_t tmp;
108 int cpu;
Andrew Mortonf67538f2009-11-13 19:55:30 -0800109 unsigned long min_weight = -1;
110 unsigned long uninitialized_var(preferred_cpu);
Shaohua Li8e0af512009-07-27 18:11:02 -0400111
112 if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
113 return;
114
115 mutex_lock(&isolated_cpus_lock);
116 cpumask_clear(tmp);
117 for_each_cpu(cpu, pad_busy_cpus)
118 cpumask_or(tmp, tmp, topology_thread_cpumask(cpu));
119 cpumask_andnot(tmp, cpu_online_mask, tmp);
120 /* avoid HT sibilings if possible */
121 if (cpumask_empty(tmp))
122 cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
123 if (cpumask_empty(tmp)) {
124 mutex_unlock(&isolated_cpus_lock);
125 return;
126 }
127 for_each_cpu(cpu, tmp) {
128 if (cpu_weight[cpu] < min_weight) {
129 min_weight = cpu_weight[cpu];
130 preferred_cpu = cpu;
131 }
132 }
133
134 if (tsk_in_cpu[tsk_index] != -1)
135 cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
136 tsk_in_cpu[tsk_index] = preferred_cpu;
137 cpumask_set_cpu(preferred_cpu, pad_busy_cpus);
138 cpu_weight[preferred_cpu]++;
139 mutex_unlock(&isolated_cpus_lock);
140
141 set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
142}
143
144static void exit_round_robin(unsigned int tsk_index)
145{
146 struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
147 cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
148 tsk_in_cpu[tsk_index] = -1;
149}
150
151static unsigned int idle_pct = 5; /* percentage */
152static unsigned int round_robin_time = 10; /* second */
153static int power_saving_thread(void *data)
154{
155 struct sched_param param = {.sched_priority = 1};
156 int do_sleep;
157 unsigned int tsk_index = (unsigned long)data;
158 u64 last_jiffies = 0;
159
160 sched_setscheduler(current, SCHED_RR, &param);
161
162 while (!kthread_should_stop()) {
163 int cpu;
164 u64 expire_time;
165
166 try_to_freeze();
167
168 /* round robin to cpus */
169 if (last_jiffies + round_robin_time * HZ < jiffies) {
170 last_jiffies = jiffies;
171 round_robin_cpu(tsk_index);
172 }
173
174 do_sleep = 0;
175
Shaohua Li8e0af512009-07-27 18:11:02 -0400176 expire_time = jiffies + HZ * (100 - idle_pct) / 100;
177
178 while (!need_resched()) {
Venkatesh Pallipadi0dc698b2010-05-18 14:39:16 -0700179 if (tsc_detected_unstable && !tsc_marked_unstable) {
180 /* TSC could halt in idle, so notify users */
181 mark_tsc_unstable("TSC halts in idle");
182 tsc_marked_unstable = 1;
183 }
Chen Gong8aa4b142010-05-30 11:37:08 +0800184 if (lapic_detected_unstable && !lapic_marked_unstable) {
185 int i;
186 /* LAPIC could halt in idle, so notify users */
187 for_each_online_cpu(i)
188 clockevents_notify(
189 CLOCK_EVT_NOTIFY_BROADCAST_ON,
190 &i);
191 lapic_marked_unstable = 1;
192 }
Shaohua Li8e0af512009-07-27 18:11:02 -0400193 local_irq_disable();
194 cpu = smp_processor_id();
Chen Gong8aa4b142010-05-30 11:37:08 +0800195 if (lapic_marked_unstable)
196 clockevents_notify(
197 CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
Shaohua Li8e0af512009-07-27 18:11:02 -0400198 stop_critical_timings();
199
200 __monitor((void *)&current_thread_info()->flags, 0, 0);
201 smp_mb();
202 if (!need_resched())
203 __mwait(power_saving_mwait_eax, 1);
204
205 start_critical_timings();
Chen Gong8aa4b142010-05-30 11:37:08 +0800206 if (lapic_marked_unstable)
207 clockevents_notify(
208 CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
Shaohua Li8e0af512009-07-27 18:11:02 -0400209 local_irq_enable();
210
211 if (jiffies > expire_time) {
212 do_sleep = 1;
213 break;
214 }
215 }
216
Shaohua Li8e0af512009-07-27 18:11:02 -0400217 /*
218 * current sched_rt has threshold for rt task running time.
219 * When a rt task uses 95% CPU time, the rt thread will be
220 * scheduled out for 5% CPU time to not starve other tasks. But
221 * the mechanism only works when all CPUs have RT task running,
222 * as if one CPU hasn't RT task, RT task from other CPUs will
223 * borrow CPU time from this CPU and cause RT task use > 95%
Chen Gong3b8cb422009-12-14 09:42:28 +0800224 * CPU time. To make 'avoid starvation' work, takes a nap here.
Shaohua Li8e0af512009-07-27 18:11:02 -0400225 */
226 if (do_sleep)
227 schedule_timeout_killable(HZ * idle_pct / 100);
228 }
229
230 exit_round_robin(tsk_index);
231 return 0;
232}
233
234static struct task_struct *ps_tsks[NR_CPUS];
235static unsigned int ps_tsk_num;
236static int create_power_saving_task(void)
237{
Chen Gong3b8cb422009-12-14 09:42:28 +0800238 int rc = -ENOMEM;
239
Shaohua Li8e0af512009-07-27 18:11:02 -0400240 ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
241 (void *)(unsigned long)ps_tsk_num,
242 "power_saving/%d", ps_tsk_num);
Chen Gong3b8cb422009-12-14 09:42:28 +0800243 rc = IS_ERR(ps_tsks[ps_tsk_num]) ? PTR_ERR(ps_tsks[ps_tsk_num]) : 0;
244 if (!rc)
Shaohua Li8e0af512009-07-27 18:11:02 -0400245 ps_tsk_num++;
Chen Gong3b8cb422009-12-14 09:42:28 +0800246 else
247 ps_tsks[ps_tsk_num] = NULL;
248
249 return rc;
Shaohua Li8e0af512009-07-27 18:11:02 -0400250}
251
252static void destroy_power_saving_task(void)
253{
254 if (ps_tsk_num > 0) {
255 ps_tsk_num--;
256 kthread_stop(ps_tsks[ps_tsk_num]);
Chen Gong3b8cb422009-12-14 09:42:28 +0800257 ps_tsks[ps_tsk_num] = NULL;
Shaohua Li8e0af512009-07-27 18:11:02 -0400258 }
259}
260
261static void set_power_saving_task_num(unsigned int num)
262{
263 if (num > ps_tsk_num) {
264 while (ps_tsk_num < num) {
265 if (create_power_saving_task())
266 return;
267 }
268 } else if (num < ps_tsk_num) {
269 while (ps_tsk_num > num)
270 destroy_power_saving_task();
271 }
272}
273
Chen Gong3b8cb422009-12-14 09:42:28 +0800274static void acpi_pad_idle_cpus(unsigned int num_cpus)
Shaohua Li8e0af512009-07-27 18:11:02 -0400275{
276 get_online_cpus();
277
278 num_cpus = min_t(unsigned int, num_cpus, num_online_cpus());
279 set_power_saving_task_num(num_cpus);
280
281 put_online_cpus();
Shaohua Li8e0af512009-07-27 18:11:02 -0400282}
283
284static uint32_t acpi_pad_idle_cpus_num(void)
285{
286 return ps_tsk_num;
287}
288
289static ssize_t acpi_pad_rrtime_store(struct device *dev,
290 struct device_attribute *attr, const char *buf, size_t count)
291{
292 unsigned long num;
293 if (strict_strtoul(buf, 0, &num))
294 return -EINVAL;
295 if (num < 1 || num >= 100)
296 return -EINVAL;
297 mutex_lock(&isolated_cpus_lock);
298 round_robin_time = num;
299 mutex_unlock(&isolated_cpus_lock);
300 return count;
301}
302
303static ssize_t acpi_pad_rrtime_show(struct device *dev,
304 struct device_attribute *attr, char *buf)
305{
306 return scnprintf(buf, PAGE_SIZE, "%d", round_robin_time);
307}
308static DEVICE_ATTR(rrtime, S_IRUGO|S_IWUSR,
309 acpi_pad_rrtime_show,
310 acpi_pad_rrtime_store);
311
312static ssize_t acpi_pad_idlepct_store(struct device *dev,
313 struct device_attribute *attr, const char *buf, size_t count)
314{
315 unsigned long num;
316 if (strict_strtoul(buf, 0, &num))
317 return -EINVAL;
318 if (num < 1 || num >= 100)
319 return -EINVAL;
320 mutex_lock(&isolated_cpus_lock);
321 idle_pct = num;
322 mutex_unlock(&isolated_cpus_lock);
323 return count;
324}
325
326static ssize_t acpi_pad_idlepct_show(struct device *dev,
327 struct device_attribute *attr, char *buf)
328{
329 return scnprintf(buf, PAGE_SIZE, "%d", idle_pct);
330}
331static DEVICE_ATTR(idlepct, S_IRUGO|S_IWUSR,
332 acpi_pad_idlepct_show,
333 acpi_pad_idlepct_store);
334
335static ssize_t acpi_pad_idlecpus_store(struct device *dev,
336 struct device_attribute *attr, const char *buf, size_t count)
337{
338 unsigned long num;
339 if (strict_strtoul(buf, 0, &num))
340 return -EINVAL;
341 mutex_lock(&isolated_cpus_lock);
342 acpi_pad_idle_cpus(num);
343 mutex_unlock(&isolated_cpus_lock);
344 return count;
345}
346
347static ssize_t acpi_pad_idlecpus_show(struct device *dev,
348 struct device_attribute *attr, char *buf)
349{
350 return cpumask_scnprintf(buf, PAGE_SIZE,
351 to_cpumask(pad_busy_cpus_bits));
352}
353static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR,
354 acpi_pad_idlecpus_show,
355 acpi_pad_idlecpus_store);
356
357static int acpi_pad_add_sysfs(struct acpi_device *device)
358{
359 int result;
360
361 result = device_create_file(&device->dev, &dev_attr_idlecpus);
362 if (result)
363 return -ENODEV;
364 result = device_create_file(&device->dev, &dev_attr_idlepct);
365 if (result) {
366 device_remove_file(&device->dev, &dev_attr_idlecpus);
367 return -ENODEV;
368 }
369 result = device_create_file(&device->dev, &dev_attr_rrtime);
370 if (result) {
371 device_remove_file(&device->dev, &dev_attr_idlecpus);
372 device_remove_file(&device->dev, &dev_attr_idlepct);
373 return -ENODEV;
374 }
375 return 0;
376}
377
378static void acpi_pad_remove_sysfs(struct acpi_device *device)
379{
380 device_remove_file(&device->dev, &dev_attr_idlecpus);
381 device_remove_file(&device->dev, &dev_attr_idlepct);
382 device_remove_file(&device->dev, &dev_attr_rrtime);
383}
384
385/* Query firmware how many CPUs should be idle */
386static int acpi_pad_pur(acpi_handle handle, int *num_cpus)
387{
388 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
Shaohua Li8e0af512009-07-27 18:11:02 -0400389 union acpi_object *package;
390 int rev, num, ret = -EINVAL;
391
Chen Gong3b8cb422009-12-14 09:42:28 +0800392 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
Shaohua Li8e0af512009-07-27 18:11:02 -0400393 return -EINVAL;
Chen Gong3b8cb422009-12-14 09:42:28 +0800394
395 if (!buffer.length || !buffer.pointer)
396 return -EINVAL;
397
Shaohua Li8e0af512009-07-27 18:11:02 -0400398 package = buffer.pointer;
399 if (package->type != ACPI_TYPE_PACKAGE || package->package.count != 2)
400 goto out;
401 rev = package->package.elements[0].integer.value;
402 num = package->package.elements[1].integer.value;
Chen Gong3b8cb422009-12-14 09:42:28 +0800403 if (rev != 1 || num < 0)
Shaohua Li8e0af512009-07-27 18:11:02 -0400404 goto out;
405 *num_cpus = num;
406 ret = 0;
407out:
408 kfree(buffer.pointer);
409 return ret;
410}
411
412/* Notify firmware how many CPUs are idle */
413static void acpi_pad_ost(acpi_handle handle, int stat,
414 uint32_t idle_cpus)
415{
416 union acpi_object params[3] = {
417 {.type = ACPI_TYPE_INTEGER,},
418 {.type = ACPI_TYPE_INTEGER,},
419 {.type = ACPI_TYPE_BUFFER,},
420 };
421 struct acpi_object_list arg_list = {3, params};
422
423 params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
424 params[1].integer.value = stat;
425 params[2].buffer.length = 4;
426 params[2].buffer.pointer = (void *)&idle_cpus;
427 acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
428}
429
430static void acpi_pad_handle_notify(acpi_handle handle)
431{
Chen Gong3b8cb422009-12-14 09:42:28 +0800432 int num_cpus;
Shaohua Li8e0af512009-07-27 18:11:02 -0400433 uint32_t idle_cpus;
434
435 mutex_lock(&isolated_cpus_lock);
436 if (acpi_pad_pur(handle, &num_cpus)) {
437 mutex_unlock(&isolated_cpus_lock);
438 return;
439 }
Chen Gong3b8cb422009-12-14 09:42:28 +0800440 acpi_pad_idle_cpus(num_cpus);
Shaohua Li8e0af512009-07-27 18:11:02 -0400441 idle_cpus = acpi_pad_idle_cpus_num();
Chen Gong3b8cb422009-12-14 09:42:28 +0800442 acpi_pad_ost(handle, 0, idle_cpus);
Shaohua Li8e0af512009-07-27 18:11:02 -0400443 mutex_unlock(&isolated_cpus_lock);
444}
445
446static void acpi_pad_notify(acpi_handle handle, u32 event,
447 void *data)
448{
449 struct acpi_device *device = data;
450
451 switch (event) {
452 case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
453 acpi_pad_handle_notify(handle);
454 acpi_bus_generate_proc_event(device, event, 0);
455 acpi_bus_generate_netlink_event(device->pnp.device_class,
456 dev_name(&device->dev), event, 0);
457 break;
458 default:
459 printk(KERN_WARNING"Unsupported event [0x%x]\n", event);
460 break;
461 }
462}
463
464static int acpi_pad_add(struct acpi_device *device)
465{
466 acpi_status status;
467
468 strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
469 strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
470
471 if (acpi_pad_add_sysfs(device))
472 return -ENODEV;
473
474 status = acpi_install_notify_handler(device->handle,
475 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
476 if (ACPI_FAILURE(status)) {
477 acpi_pad_remove_sysfs(device);
478 return -ENODEV;
479 }
480
481 return 0;
482}
483
484static int acpi_pad_remove(struct acpi_device *device,
485 int type)
486{
487 mutex_lock(&isolated_cpus_lock);
488 acpi_pad_idle_cpus(0);
489 mutex_unlock(&isolated_cpus_lock);
490
491 acpi_remove_notify_handler(device->handle,
492 ACPI_DEVICE_NOTIFY, acpi_pad_notify);
493 acpi_pad_remove_sysfs(device);
494 return 0;
495}
496
497static const struct acpi_device_id pad_device_ids[] = {
498 {"ACPI000C", 0},
499 {"", 0},
500};
501MODULE_DEVICE_TABLE(acpi, pad_device_ids);
502
503static struct acpi_driver acpi_pad_driver = {
504 .name = "processor_aggregator",
505 .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
506 .ids = pad_device_ids,
507 .ops = {
508 .add = acpi_pad_add,
509 .remove = acpi_pad_remove,
510 },
511};
512
513static int __init acpi_pad_init(void)
514{
515 power_saving_mwait_init();
516 if (power_saving_mwait_eax == 0)
517 return -EINVAL;
518
519 return acpi_bus_register_driver(&acpi_pad_driver);
520}
521
522static void __exit acpi_pad_exit(void)
523{
524 acpi_bus_unregister_driver(&acpi_pad_driver);
525}
526
527module_init(acpi_pad_init);
528module_exit(acpi_pad_exit);
529MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
530MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
531MODULE_LICENSE("GPL");