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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 <acpi/acpi_bus.h>
31#include <acpi/acpi_drivers.h>
32
33#define ACPI_PROCESSOR_AGGREGATOR_CLASS "processor_aggregator"
34#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
35#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
36static DEFINE_MUTEX(isolated_cpus_lock);
37
38#define MWAIT_SUBSTATE_MASK (0xf)
39#define MWAIT_CSTATE_MASK (0xf)
40#define MWAIT_SUBSTATE_SIZE (4)
41#define CPUID_MWAIT_LEAF (5)
42#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1)
43#define CPUID5_ECX_INTERRUPT_BREAK (0x2)
44static unsigned long power_saving_mwait_eax;
45static void power_saving_mwait_init(void)
46{
47 unsigned int eax, ebx, ecx, edx;
48 unsigned int highest_cstate = 0;
49 unsigned int highest_subcstate = 0;
50 int i;
51
52 if (!boot_cpu_has(X86_FEATURE_MWAIT))
53 return;
54 if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
55 return;
56
57 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
58
59 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
60 !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
61 return;
62
63 edx >>= MWAIT_SUBSTATE_SIZE;
64 for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
65 if (edx & MWAIT_SUBSTATE_MASK) {
66 highest_cstate = i;
67 highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
68 }
69 }
70 power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
71 (highest_subcstate - 1);
72
73 for_each_online_cpu(i)
74 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &i);
75
76#if defined(CONFIG_GENERIC_TIME) && defined(CONFIG_X86)
77 switch (boot_cpu_data.x86_vendor) {
78 case X86_VENDOR_AMD:
79 case X86_VENDOR_INTEL:
80
81
82
83
84 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
85 return;
86
87
88 default:
89
90 mark_tsc_unstable("TSC halts in idle");
91 }
92#endif
93}
94
95static unsigned long cpu_weight[NR_CPUS];
96static int tsk_in_cpu[NR_CPUS] = {[0 ... NR_CPUS-1] = -1};
97static DECLARE_BITMAP(pad_busy_cpus_bits, NR_CPUS);
98static void round_robin_cpu(unsigned int tsk_index)
99{
100 struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
101 cpumask_var_t tmp;
102 int cpu;
103 unsigned long min_weight = -1, preferred_cpu;
104
105 if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
106 return;
107
108 mutex_lock(&isolated_cpus_lock);
109 cpumask_clear(tmp);
110 for_each_cpu(cpu, pad_busy_cpus)
111 cpumask_or(tmp, tmp, topology_thread_cpumask(cpu));
112 cpumask_andnot(tmp, cpu_online_mask, tmp);
113
114 if (cpumask_empty(tmp))
115 cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
116 if (cpumask_empty(tmp)) {
117 mutex_unlock(&isolated_cpus_lock);
118 return;
119 }
120 for_each_cpu(cpu, tmp) {
121 if (cpu_weight[cpu] < min_weight) {
122 min_weight = cpu_weight[cpu];
123 preferred_cpu = cpu;
124 }
125 }
126
127 if (tsk_in_cpu[tsk_index] != -1)
128 cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
129 tsk_in_cpu[tsk_index] = preferred_cpu;
130 cpumask_set_cpu(preferred_cpu, pad_busy_cpus);
131 cpu_weight[preferred_cpu]++;
132 mutex_unlock(&isolated_cpus_lock);
133
134 set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
135}
136
137static void exit_round_robin(unsigned int tsk_index)
138{
139 struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
140 cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
141 tsk_in_cpu[tsk_index] = -1;
142}
143
144static unsigned int idle_pct = 5;
145static unsigned int round_robin_time = 10;
146static int power_saving_thread(void *data)
147{
148 struct sched_param param = {.sched_priority = 1};
149 int do_sleep;
150 unsigned int tsk_index = (unsigned long)data;
151 u64 last_jiffies = 0;
152
153 sched_setscheduler(current, SCHED_RR, ¶m);
154
155 while (!kthread_should_stop()) {
156 int cpu;
157 u64 expire_time;
158
159 try_to_freeze();
160
161
162 if (last_jiffies + round_robin_time * HZ < jiffies) {
163 last_jiffies = jiffies;
164 round_robin_cpu(tsk_index);
165 }
166
167 do_sleep = 0;
168
169 current_thread_info()->status &= ~TS_POLLING;
170
171
172
173
174 smp_mb();
175
176 expire_time = jiffies + HZ * (100 - idle_pct) / 100;
177
178 while (!need_resched()) {
179 local_irq_disable();
180 cpu = smp_processor_id();
181 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
182 &cpu);
183 stop_critical_timings();
184
185 __monitor((void *)¤t_thread_info()->flags, 0, 0);
186 smp_mb();
187 if (!need_resched())
188 __mwait(power_saving_mwait_eax, 1);
189
190 start_critical_timings();
191 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
192 &cpu);
193 local_irq_enable();
194
195 if (jiffies > expire_time) {
196 do_sleep = 1;
197 break;
198 }
199 }
200
201 current_thread_info()->status |= TS_POLLING;
202
203
204
205
206
207
208
209
210
211
212 if (do_sleep)
213 schedule_timeout_killable(HZ * idle_pct / 100);
214 }
215
216 exit_round_robin(tsk_index);
217 return 0;
218}
219
220static struct task_struct *ps_tsks[NR_CPUS];
221static unsigned int ps_tsk_num;
222static int create_power_saving_task(void)
223{
224 ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
225 (void *)(unsigned long)ps_tsk_num,
226 "power_saving/%d", ps_tsk_num);
227 if (ps_tsks[ps_tsk_num]) {
228 ps_tsk_num++;
229 return 0;
230 }
231 return -EINVAL;
232}
233
234static void destroy_power_saving_task(void)
235{
236 if (ps_tsk_num > 0) {
237 ps_tsk_num--;
238 kthread_stop(ps_tsks[ps_tsk_num]);
239 }
240}
241
242static void set_power_saving_task_num(unsigned int num)
243{
244 if (num > ps_tsk_num) {
245 while (ps_tsk_num < num) {
246 if (create_power_saving_task())
247 return;
248 }
249 } else if (num < ps_tsk_num) {
250 while (ps_tsk_num > num)
251 destroy_power_saving_task();
252 }
253}
254
255static int acpi_pad_idle_cpus(unsigned int num_cpus)
256{
257 get_online_cpus();
258
259 num_cpus = min_t(unsigned int, num_cpus, num_online_cpus());
260 set_power_saving_task_num(num_cpus);
261
262 put_online_cpus();
263 return 0;
264}
265
266static uint32_t acpi_pad_idle_cpus_num(void)
267{
268 return ps_tsk_num;
269}
270
271static ssize_t acpi_pad_rrtime_store(struct device *dev,
272 struct device_attribute *attr, const char *buf, size_t count)
273{
274 unsigned long num;
275 if (strict_strtoul(buf, 0, &num))
276 return -EINVAL;
277 if (num < 1 || num >= 100)
278 return -EINVAL;
279 mutex_lock(&isolated_cpus_lock);
280 round_robin_time = num;
281 mutex_unlock(&isolated_cpus_lock);
282 return count;
283}
284
285static ssize_t acpi_pad_rrtime_show(struct device *dev,
286 struct device_attribute *attr, char *buf)
287{
288 return scnprintf(buf, PAGE_SIZE, "%d", round_robin_time);
289}
290static DEVICE_ATTR(rrtime, S_IRUGO|S_IWUSR,
291 acpi_pad_rrtime_show,
292 acpi_pad_rrtime_store);
293
294static ssize_t acpi_pad_idlepct_store(struct device *dev,
295 struct device_attribute *attr, const char *buf, size_t count)
296{
297 unsigned long num;
298 if (strict_strtoul(buf, 0, &num))
299 return -EINVAL;
300 if (num < 1 || num >= 100)
301 return -EINVAL;
302 mutex_lock(&isolated_cpus_lock);
303 idle_pct = num;
304 mutex_unlock(&isolated_cpus_lock);
305 return count;
306}
307
308static ssize_t acpi_pad_idlepct_show(struct device *dev,
309 struct device_attribute *attr, char *buf)
310{
311 return scnprintf(buf, PAGE_SIZE, "%d", idle_pct);
312}
313static DEVICE_ATTR(idlepct, S_IRUGO|S_IWUSR,
314 acpi_pad_idlepct_show,
315 acpi_pad_idlepct_store);
316
317static ssize_t acpi_pad_idlecpus_store(struct device *dev,
318 struct device_attribute *attr, const char *buf, size_t count)
319{
320 unsigned long num;
321 if (strict_strtoul(buf, 0, &num))
322 return -EINVAL;
323 mutex_lock(&isolated_cpus_lock);
324 acpi_pad_idle_cpus(num);
325 mutex_unlock(&isolated_cpus_lock);
326 return count;
327}
328
329static ssize_t acpi_pad_idlecpus_show(struct device *dev,
330 struct device_attribute *attr, char *buf)
331{
332 return cpumask_scnprintf(buf, PAGE_SIZE,
333 to_cpumask(pad_busy_cpus_bits));
334}
335static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR,
336 acpi_pad_idlecpus_show,
337 acpi_pad_idlecpus_store);
338
339static int acpi_pad_add_sysfs(struct acpi_device *device)
340{
341 int result;
342
343 result = device_create_file(&device->dev, &dev_attr_idlecpus);
344 if (result)
345 return -ENODEV;
346 result = device_create_file(&device->dev, &dev_attr_idlepct);
347 if (result) {
348 device_remove_file(&device->dev, &dev_attr_idlecpus);
349 return -ENODEV;
350 }
351 result = device_create_file(&device->dev, &dev_attr_rrtime);
352 if (result) {
353 device_remove_file(&device->dev, &dev_attr_idlecpus);
354 device_remove_file(&device->dev, &dev_attr_idlepct);
355 return -ENODEV;
356 }
357 return 0;
358}
359
360static void acpi_pad_remove_sysfs(struct acpi_device *device)
361{
362 device_remove_file(&device->dev, &dev_attr_idlecpus);
363 device_remove_file(&device->dev, &dev_attr_idlepct);
364 device_remove_file(&device->dev, &dev_attr_rrtime);
365}
366
367
368static int acpi_pad_pur(acpi_handle handle, int *num_cpus)
369{
370 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
371 acpi_status status;
372 union acpi_object *package;
373 int rev, num, ret = -EINVAL;
374
375 status = acpi_evaluate_object(handle, "_PUR", NULL, &buffer);
376 if (ACPI_FAILURE(status))
377 return -EINVAL;
378 package = buffer.pointer;
379 if (package->type != ACPI_TYPE_PACKAGE || package->package.count != 2)
380 goto out;
381 rev = package->package.elements[0].integer.value;
382 num = package->package.elements[1].integer.value;
383 if (rev != 1)
384 goto out;
385 *num_cpus = num;
386 ret = 0;
387out:
388 kfree(buffer.pointer);
389 return ret;
390}
391
392
393static void acpi_pad_ost(acpi_handle handle, int stat,
394 uint32_t idle_cpus)
395{
396 union acpi_object params[3] = {
397 {.type = ACPI_TYPE_INTEGER,},
398 {.type = ACPI_TYPE_INTEGER,},
399 {.type = ACPI_TYPE_BUFFER,},
400 };
401 struct acpi_object_list arg_list = {3, params};
402
403 params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
404 params[1].integer.value = stat;
405 params[2].buffer.length = 4;
406 params[2].buffer.pointer = (void *)&idle_cpus;
407 acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
408}
409
410static void acpi_pad_handle_notify(acpi_handle handle)
411{
412 int num_cpus, ret;
413 uint32_t idle_cpus;
414
415 mutex_lock(&isolated_cpus_lock);
416 if (acpi_pad_pur(handle, &num_cpus)) {
417 mutex_unlock(&isolated_cpus_lock);
418 return;
419 }
420 ret = acpi_pad_idle_cpus(num_cpus);
421 idle_cpus = acpi_pad_idle_cpus_num();
422 if (!ret)
423 acpi_pad_ost(handle, 0, idle_cpus);
424 else
425 acpi_pad_ost(handle, 1, 0);
426 mutex_unlock(&isolated_cpus_lock);
427}
428
429static void acpi_pad_notify(acpi_handle handle, u32 event,
430 void *data)
431{
432 struct acpi_device *device = data;
433
434 switch (event) {
435 case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
436 acpi_pad_handle_notify(handle);
437 acpi_bus_generate_proc_event(device, event, 0);
438 acpi_bus_generate_netlink_event(device->pnp.device_class,
439 dev_name(&device->dev), event, 0);
440 break;
441 default:
442 printk(KERN_WARNING"Unsupported event [0x%x]\n", event);
443 break;
444 }
445}
446
447static int acpi_pad_add(struct acpi_device *device)
448{
449 acpi_status status;
450
451 strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
452 strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
453
454 if (acpi_pad_add_sysfs(device))
455 return -ENODEV;
456
457 status = acpi_install_notify_handler(device->handle,
458 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
459 if (ACPI_FAILURE(status)) {
460 acpi_pad_remove_sysfs(device);
461 return -ENODEV;
462 }
463
464 return 0;
465}
466
467static int acpi_pad_remove(struct acpi_device *device,
468 int type)
469{
470 mutex_lock(&isolated_cpus_lock);
471 acpi_pad_idle_cpus(0);
472 mutex_unlock(&isolated_cpus_lock);
473
474 acpi_remove_notify_handler(device->handle,
475 ACPI_DEVICE_NOTIFY, acpi_pad_notify);
476 acpi_pad_remove_sysfs(device);
477 return 0;
478}
479
480static const struct acpi_device_id pad_device_ids[] = {
481 {"ACPI000C", 0},
482 {"", 0},
483};
484MODULE_DEVICE_TABLE(acpi, pad_device_ids);
485
486static struct acpi_driver acpi_pad_driver = {
487 .name = "processor_aggregator",
488 .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
489 .ids = pad_device_ids,
490 .ops = {
491 .add = acpi_pad_add,
492 .remove = acpi_pad_remove,
493 },
494};
495
496static int __init acpi_pad_init(void)
497{
498 power_saving_mwait_init();
499 if (power_saving_mwait_eax == 0)
500 return -EINVAL;
501
502 return acpi_bus_register_driver(&acpi_pad_driver);
503}
504
505static void __exit acpi_pad_exit(void)
506{
507 acpi_bus_unregister_driver(&acpi_pad_driver);
508}
509
510module_init(acpi_pad_init);
511module_exit(acpi_pad_exit);
512MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
513MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
514MODULE_LICENSE("GPL");
515
