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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>
30#include <linux/slab.h>
31#include <linux/acpi.h>
32#include <asm/mwait.h>
33
34#define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
35#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
36#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
37static DEFINE_MUTEX(isolated_cpus_lock);
38static DEFINE_MUTEX(round_robin_lock);
39
40static unsigned long power_saving_mwait_eax;
41
42static unsigned char tsc_detected_unstable;
43static unsigned char tsc_marked_unstable;
44static unsigned char lapic_detected_unstable;
45static unsigned char lapic_marked_unstable;
46
47static void power_saving_mwait_init(void)
48{
49 unsigned int eax, ebx, ecx, edx;
50 unsigned int highest_cstate = 0;
51 unsigned int highest_subcstate = 0;
52 int i;
53
54 if (!boot_cpu_has(X86_FEATURE_MWAIT))
55 return;
56 if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
57 return;
58
59 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
60
61 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
62 !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
63 return;
64
65 edx >>= MWAIT_SUBSTATE_SIZE;
66 for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
67 if (edx & MWAIT_SUBSTATE_MASK) {
68 highest_cstate = i;
69 highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
70 }
71 }
72 power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
73 (highest_subcstate - 1);
74
75#if defined(CONFIG_X86)
76 switch (boot_cpu_data.x86_vendor) {
77 case X86_VENDOR_AMD:
78 case X86_VENDOR_INTEL:
79
80
81
82
83 if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
84 tsc_detected_unstable = 1;
85 if (!boot_cpu_has(X86_FEATURE_ARAT))
86 lapic_detected_unstable = 1;
87 break;
88 default:
89
90 tsc_detected_unstable = 1;
91 lapic_detected_unstable = 1;
92 }
93#endif
94}
95
96static unsigned long cpu_weight[NR_CPUS];
97static int tsk_in_cpu[NR_CPUS] = {[0 ... NR_CPUS-1] = -1};
98static DECLARE_BITMAP(pad_busy_cpus_bits, NR_CPUS);
99static void round_robin_cpu(unsigned int tsk_index)
100{
101 struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
102 cpumask_var_t tmp;
103 int cpu;
104 unsigned long min_weight = -1;
105 unsigned long uninitialized_var(preferred_cpu);
106
107 if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
108 return;
109
110 mutex_lock(&round_robin_lock);
111 cpumask_clear(tmp);
112 for_each_cpu(cpu, pad_busy_cpus)
113 cpumask_or(tmp, tmp, topology_thread_cpumask(cpu));
114 cpumask_andnot(tmp, cpu_online_mask, tmp);
115
116 if (cpumask_empty(tmp))
117 cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
118 if (cpumask_empty(tmp)) {
119 mutex_unlock(&round_robin_lock);
120 return;
121 }
122 for_each_cpu(cpu, tmp) {
123 if (cpu_weight[cpu] < min_weight) {
124 min_weight = cpu_weight[cpu];
125 preferred_cpu = cpu;
126 }
127 }
128
129 if (tsk_in_cpu[tsk_index] != -1)
130 cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
131 tsk_in_cpu[tsk_index] = preferred_cpu;
132 cpumask_set_cpu(preferred_cpu, pad_busy_cpus);
133 cpu_weight[preferred_cpu]++;
134 mutex_unlock(&round_robin_lock);
135
136 set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
137}
138
139static void exit_round_robin(unsigned int tsk_index)
140{
141 struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
142 cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
143 tsk_in_cpu[tsk_index] = -1;
144}
145
146static unsigned int idle_pct = 5;
147static unsigned int round_robin_time = 1;
148static int power_saving_thread(void *data)
149{
150 struct sched_param param = {.sched_priority = 1};
151 int do_sleep;
152 unsigned int tsk_index = (unsigned long)data;
153 u64 last_jiffies = 0;
154
155 sched_setscheduler(current, SCHED_RR, ¶m);
156
157 while (!kthread_should_stop()) {
158 int cpu;
159 u64 expire_time;
160
161 try_to_freeze();
162
163
164 if (last_jiffies + round_robin_time * HZ < jiffies) {
165 last_jiffies = jiffies;
166 round_robin_cpu(tsk_index);
167 }
168
169 do_sleep = 0;
170
171 expire_time = jiffies + HZ * (100 - idle_pct) / 100;
172
173 while (!need_resched()) {
174 if (tsc_detected_unstable && !tsc_marked_unstable) {
175
176 mark_tsc_unstable("TSC halts in idle");
177 tsc_marked_unstable = 1;
178 }
179 if (lapic_detected_unstable && !lapic_marked_unstable) {
180 int i;
181
182 for_each_online_cpu(i)
183 clockevents_notify(
184 CLOCK_EVT_NOTIFY_BROADCAST_ON,
185 &i);
186 lapic_marked_unstable = 1;
187 }
188 local_irq_disable();
189 cpu = smp_processor_id();
190 if (lapic_marked_unstable)
191 clockevents_notify(
192 CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
193 stop_critical_timings();
194
195 mwait_idle_with_hints(power_saving_mwait_eax, 1);
196
197 start_critical_timings();
198 if (lapic_marked_unstable)
199 clockevents_notify(
200 CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
201 local_irq_enable();
202
203 if (jiffies > expire_time) {
204 do_sleep = 1;
205 break;
206 }
207 }
208
209
210
211
212
213
214
215
216
217
218 if (do_sleep)
219 schedule_timeout_killable(HZ * idle_pct / 100);
220 }
221
222 exit_round_robin(tsk_index);
223 return 0;
224}
225
226static struct task_struct *ps_tsks[NR_CPUS];
227static unsigned int ps_tsk_num;
228static int create_power_saving_task(void)
229{
230 int rc;
231
232 ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
233 (void *)(unsigned long)ps_tsk_num,
234 "acpi_pad/%d", ps_tsk_num);
235
236 if (IS_ERR(ps_tsks[ps_tsk_num])) {
237 rc = PTR_ERR(ps_tsks[ps_tsk_num]);
238 ps_tsks[ps_tsk_num] = NULL;
239 } else {
240 rc = 0;
241 ps_tsk_num++;
242 }
243
244 return rc;
245}
246
247static void destroy_power_saving_task(void)
248{
249 if (ps_tsk_num > 0) {
250 ps_tsk_num--;
251 kthread_stop(ps_tsks[ps_tsk_num]);
252 ps_tsks[ps_tsk_num] = NULL;
253 }
254}
255
256static void set_power_saving_task_num(unsigned int num)
257{
258 if (num > ps_tsk_num) {
259 while (ps_tsk_num < num) {
260 if (create_power_saving_task())
261 return;
262 }
263 } else if (num < ps_tsk_num) {
264 while (ps_tsk_num > num)
265 destroy_power_saving_task();
266 }
267}
268
269static void acpi_pad_idle_cpus(unsigned int num_cpus)
270{
271 get_online_cpus();
272
273 num_cpus = min_t(unsigned int, num_cpus, num_online_cpus());
274 set_power_saving_task_num(num_cpus);
275
276 put_online_cpus();
277}
278
279static uint32_t acpi_pad_idle_cpus_num(void)
280{
281 return ps_tsk_num;
282}
283
284static ssize_t acpi_pad_rrtime_store(struct device *dev,
285 struct device_attribute *attr, const char *buf, size_t count)
286{
287 unsigned long num;
288 if (kstrtoul(buf, 0, &num))
289 return -EINVAL;
290 if (num < 1 || num >= 100)
291 return -EINVAL;
292 mutex_lock(&isolated_cpus_lock);
293 round_robin_time = num;
294 mutex_unlock(&isolated_cpus_lock);
295 return count;
296}
297
298static ssize_t acpi_pad_rrtime_show(struct device *dev,
299 struct device_attribute *attr, char *buf)
300{
301 return scnprintf(buf, PAGE_SIZE, "%d\n", round_robin_time);
302}
303static DEVICE_ATTR(rrtime, S_IRUGO|S_IWUSR,
304 acpi_pad_rrtime_show,
305 acpi_pad_rrtime_store);
306
307static ssize_t acpi_pad_idlepct_store(struct device *dev,
308 struct device_attribute *attr, const char *buf, size_t count)
309{
310 unsigned long num;
311 if (kstrtoul(buf, 0, &num))
312 return -EINVAL;
313 if (num < 1 || num >= 100)
314 return -EINVAL;
315 mutex_lock(&isolated_cpus_lock);
316 idle_pct = num;
317 mutex_unlock(&isolated_cpus_lock);
318 return count;
319}
320
321static ssize_t acpi_pad_idlepct_show(struct device *dev,
322 struct device_attribute *attr, char *buf)
323{
324 return scnprintf(buf, PAGE_SIZE, "%d\n", idle_pct);
325}
326static DEVICE_ATTR(idlepct, S_IRUGO|S_IWUSR,
327 acpi_pad_idlepct_show,
328 acpi_pad_idlepct_store);
329
330static ssize_t acpi_pad_idlecpus_store(struct device *dev,
331 struct device_attribute *attr, const char *buf, size_t count)
332{
333 unsigned long num;
334 if (kstrtoul(buf, 0, &num))
335 return -EINVAL;
336 mutex_lock(&isolated_cpus_lock);
337 acpi_pad_idle_cpus(num);
338 mutex_unlock(&isolated_cpus_lock);
339 return count;
340}
341
342static ssize_t acpi_pad_idlecpus_show(struct device *dev,
343 struct device_attribute *attr, char *buf)
344{
345 int n = 0;
346 n = cpumask_scnprintf(buf, PAGE_SIZE-2, to_cpumask(pad_busy_cpus_bits));
347 buf[n++] = '\n';
348 buf[n] = '\0';
349 return n;
350}
351static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR,
352 acpi_pad_idlecpus_show,
353 acpi_pad_idlecpus_store);
354
355static int acpi_pad_add_sysfs(struct acpi_device *device)
356{
357 int result;
358
359 result = device_create_file(&device->dev, &dev_attr_idlecpus);
360 if (result)
361 return -ENODEV;
362 result = device_create_file(&device->dev, &dev_attr_idlepct);
363 if (result) {
364 device_remove_file(&device->dev, &dev_attr_idlecpus);
365 return -ENODEV;
366 }
367 result = device_create_file(&device->dev, &dev_attr_rrtime);
368 if (result) {
369 device_remove_file(&device->dev, &dev_attr_idlecpus);
370 device_remove_file(&device->dev, &dev_attr_idlepct);
371 return -ENODEV;
372 }
373 return 0;
374}
375
376static void acpi_pad_remove_sysfs(struct acpi_device *device)
377{
378 device_remove_file(&device->dev, &dev_attr_idlecpus);
379 device_remove_file(&device->dev, &dev_attr_idlepct);
380 device_remove_file(&device->dev, &dev_attr_rrtime);
381}
382
383
384
385
386
387static int acpi_pad_pur(acpi_handle handle)
388{
389 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
390 union acpi_object *package;
391 int num = -1;
392
393 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
394 return num;
395
396 if (!buffer.length || !buffer.pointer)
397 return num;
398
399 package = buffer.pointer;
400
401 if (package->type == ACPI_TYPE_PACKAGE &&
402 package->package.count == 2 &&
403 package->package.elements[0].integer.value == 1)
404
405 num = package->package.elements[1].integer.value;
406
407 kfree(buffer.pointer);
408 return num;
409}
410
411
412static void acpi_pad_ost(acpi_handle handle, int stat,
413 uint32_t idle_cpus)
414{
415 union acpi_object params[3] = {
416 {.type = ACPI_TYPE_INTEGER,},
417 {.type = ACPI_TYPE_INTEGER,},
418 {.type = ACPI_TYPE_BUFFER,},
419 };
420 struct acpi_object_list arg_list = {3, params};
421
422 params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
423 params[1].integer.value = stat;
424 params[2].buffer.length = 4;
425 params[2].buffer.pointer = (void *)&idle_cpus;
426 acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
427}
428
429static void acpi_pad_handle_notify(acpi_handle handle)
430{
431 int num_cpus;
432 uint32_t idle_cpus;
433
434 mutex_lock(&isolated_cpus_lock);
435 num_cpus = acpi_pad_pur(handle);
436 if (num_cpus < 0) {
437 mutex_unlock(&isolated_cpus_lock);
438 return;
439 }
440 acpi_pad_idle_cpus(num_cpus);
441 idle_cpus = acpi_pad_idle_cpus_num();
442 acpi_pad_ost(handle, 0, idle_cpus);
443 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_netlink_event(device->pnp.device_class,
455 dev_name(&device->dev), event, 0);
456 break;
457 default:
458 pr_warn("Unsupported event [0x%x]\n", event);
459 break;
460 }
461}
462
463static int acpi_pad_add(struct acpi_device *device)
464{
465 acpi_status status;
466
467 strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
468 strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
469
470 if (acpi_pad_add_sysfs(device))
471 return -ENODEV;
472
473 status = acpi_install_notify_handler(device->handle,
474 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
475 if (ACPI_FAILURE(status)) {
476 acpi_pad_remove_sysfs(device);
477 return -ENODEV;
478 }
479
480 return 0;
481}
482
483static int acpi_pad_remove(struct acpi_device *device)
484{
485 mutex_lock(&isolated_cpus_lock);
486 acpi_pad_idle_cpus(0);
487 mutex_unlock(&isolated_cpus_lock);
488
489 acpi_remove_notify_handler(device->handle,
490 ACPI_DEVICE_NOTIFY, acpi_pad_notify);
491 acpi_pad_remove_sysfs(device);
492 return 0;
493}
494
495static const struct acpi_device_id pad_device_ids[] = {
496 {"ACPI000C", 0},
497 {"", 0},
498};
499MODULE_DEVICE_TABLE(acpi, pad_device_ids);
500
501static struct acpi_driver acpi_pad_driver = {
502 .name = "processor_aggregator",
503 .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
504 .ids = pad_device_ids,
505 .ops = {
506 .add = acpi_pad_add,
507 .remove = acpi_pad_remove,
508 },
509};
510
511static int __init acpi_pad_init(void)
512{
513 power_saving_mwait_init();
514 if (power_saving_mwait_eax == 0)
515 return -EINVAL;
516
517 return acpi_bus_register_driver(&acpi_pad_driver);
518}
519
520static void __exit acpi_pad_exit(void)
521{
522 acpi_bus_unregister_driver(&acpi_pad_driver);
523}
524
525module_init(acpi_pad_init);
526module_exit(acpi_pad_exit);
527MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
528MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
529MODULE_LICENSE("GPL");
530
