ACPI: create Processor Aggregator Device driver
[linux-2.6.git] / drivers / acpi / acpi_pad.c
1 /*
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>
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
36 static 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)
44 static unsigned long power_saving_mwait_eax;
45 static 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                  * AMD Fam10h TSC will tick in all
82                  * C/P/S0/S1 states when this bit is set.
83                  */
84                 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
85                         return;
86
87                 /*FALL THROUGH*/
88         default:
89                 /* TSC could halt in idle, so notify users */
90                 mark_tsc_unstable("TSC halts in idle");
91         }
92 #endif
93 }
94
95 static unsigned long cpu_weight[NR_CPUS];
96 static int tsk_in_cpu[NR_CPUS] = {[0 ... NR_CPUS-1] = -1};
97 static DECLARE_BITMAP(pad_busy_cpus_bits, NR_CPUS);
98 static 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         /* avoid HT sibilings if possible */
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
137 static 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
144 static unsigned int idle_pct = 5; /* percentage */
145 static unsigned int round_robin_time = 10; /* second */
146 static 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, &param);
154
155         while (!kthread_should_stop()) {
156                 int cpu;
157                 u64 expire_time;
158
159                 try_to_freeze();
160
161                 /* round robin to cpus */
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                  * TS_POLLING-cleared state must be visible before we test
172                  * NEED_RESCHED:
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 *)&current_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                  * current sched_rt has threshold for rt task running time.
205                  * When a rt task uses 95% CPU time, the rt thread will be
206                  * scheduled out for 5% CPU time to not starve other tasks. But
207                  * the mechanism only works when all CPUs have RT task running,
208                  * as if one CPU hasn't RT task, RT task from other CPUs will
209                  * borrow CPU time from this CPU and cause RT task use > 95%
210                  * CPU time. To make 'avoid staration' work, takes a nap here.
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
220 static struct task_struct *ps_tsks[NR_CPUS];
221 static unsigned int ps_tsk_num;
222 static 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
234 static 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
242 static 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
255 static 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
266 static uint32_t acpi_pad_idle_cpus_num(void)
267 {
268         return ps_tsk_num;
269 }
270
271 static 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
285 static 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 }
290 static DEVICE_ATTR(rrtime, S_IRUGO|S_IWUSR,
291         acpi_pad_rrtime_show,
292         acpi_pad_rrtime_store);
293
294 static 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
308 static 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 }
313 static DEVICE_ATTR(idlepct, S_IRUGO|S_IWUSR,
314         acpi_pad_idlepct_show,
315         acpi_pad_idlepct_store);
316
317 static 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
329 static 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 }
335 static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR,
336         acpi_pad_idlecpus_show,
337         acpi_pad_idlecpus_store);
338
339 static 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
360 static 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 /* Query firmware how many CPUs should be idle */
368 static 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;
387 out:
388         kfree(buffer.pointer);
389         return ret;
390 }
391
392 /* Notify firmware how many CPUs are idle */
393 static 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
410 static 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
429 static 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
447 static 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
467 static 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
480 static const struct acpi_device_id pad_device_ids[] = {
481         {"ACPI000C", 0},
482         {"", 0},
483 };
484 MODULE_DEVICE_TABLE(acpi, pad_device_ids);
485
486 static 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
496 static 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
505 static void __exit acpi_pad_exit(void)
506 {
507         acpi_bus_unregister_driver(&acpi_pad_driver);
508 }
509
510 module_init(acpi_pad_init);
511 module_exit(acpi_pad_exit);
512 MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
513 MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
514 MODULE_LICENSE("GPL");