include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit...
[linux-3.10.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 <linux/slab.h>
31 #include <acpi/acpi_bus.h>
32 #include <acpi/acpi_drivers.h>
33
34 #define ACPI_PROCESSOR_AGGREGATOR_CLASS "processor_aggregator"
35 #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
36 #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
37 static 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)
45 static unsigned long power_saving_mwait_eax;
46 static void power_saving_mwait_init(void)
47 {
48         unsigned int eax, ebx, ecx, edx;
49         unsigned int highest_cstate = 0;
50         unsigned int highest_subcstate = 0;
51         int i;
52
53         if (!boot_cpu_has(X86_FEATURE_MWAIT))
54                 return;
55         if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
56                 return;
57
58         cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
59
60         if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
61             !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
62                 return;
63
64         edx >>= MWAIT_SUBSTATE_SIZE;
65         for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
66                 if (edx & MWAIT_SUBSTATE_MASK) {
67                         highest_cstate = i;
68                         highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
69                 }
70         }
71         power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
72                 (highest_subcstate - 1);
73
74         for_each_online_cpu(i)
75                 clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &i);
76
77 #if defined(CONFIG_GENERIC_TIME) && defined(CONFIG_X86)
78         switch (boot_cpu_data.x86_vendor) {
79         case X86_VENDOR_AMD:
80         case X86_VENDOR_INTEL:
81                 /*
82                  * AMD Fam10h TSC will tick in all
83                  * C/P/S0/S1 states when this bit is set.
84                  */
85                 if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
86                         return;
87
88                 /*FALL THROUGH*/
89         default:
90                 /* TSC could halt in idle, so notify users */
91                 mark_tsc_unstable("TSC halts in idle");
92         }
93 #endif
94 }
95
96 static unsigned long cpu_weight[NR_CPUS];
97 static int tsk_in_cpu[NR_CPUS] = {[0 ... NR_CPUS-1] = -1};
98 static DECLARE_BITMAP(pad_busy_cpus_bits, NR_CPUS);
99 static 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(&isolated_cpus_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         /* avoid HT sibilings if possible */
116         if (cpumask_empty(tmp))
117                 cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
118         if (cpumask_empty(tmp)) {
119                 mutex_unlock(&isolated_cpus_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(&isolated_cpus_lock);
135
136         set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
137 }
138
139 static 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
146 static unsigned int idle_pct = 5; /* percentage */
147 static unsigned int round_robin_time = 10; /* second */
148 static 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, &param);
156
157         while (!kthread_should_stop()) {
158                 int cpu;
159                 u64 expire_time;
160
161                 try_to_freeze();
162
163                 /* round robin to cpus */
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                 current_thread_info()->status &= ~TS_POLLING;
172                 /*
173                  * TS_POLLING-cleared state must be visible before we test
174                  * NEED_RESCHED:
175                  */
176                 smp_mb();
177
178                 expire_time = jiffies + HZ * (100 - idle_pct) / 100;
179
180                 while (!need_resched()) {
181                         local_irq_disable();
182                         cpu = smp_processor_id();
183                         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
184                                 &cpu);
185                         stop_critical_timings();
186
187                         __monitor((void *)&current_thread_info()->flags, 0, 0);
188                         smp_mb();
189                         if (!need_resched())
190                                 __mwait(power_saving_mwait_eax, 1);
191
192                         start_critical_timings();
193                         clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
194                                 &cpu);
195                         local_irq_enable();
196
197                         if (jiffies > expire_time) {
198                                 do_sleep = 1;
199                                 break;
200                         }
201                 }
202
203                 current_thread_info()->status |= TS_POLLING;
204
205                 /*
206                  * current sched_rt has threshold for rt task running time.
207                  * When a rt task uses 95% CPU time, the rt thread will be
208                  * scheduled out for 5% CPU time to not starve other tasks. But
209                  * the mechanism only works when all CPUs have RT task running,
210                  * as if one CPU hasn't RT task, RT task from other CPUs will
211                  * borrow CPU time from this CPU and cause RT task use > 95%
212                  * CPU time. To make 'avoid starvation' work, takes a nap here.
213                  */
214                 if (do_sleep)
215                         schedule_timeout_killable(HZ * idle_pct / 100);
216         }
217
218         exit_round_robin(tsk_index);
219         return 0;
220 }
221
222 static struct task_struct *ps_tsks[NR_CPUS];
223 static unsigned int ps_tsk_num;
224 static int create_power_saving_task(void)
225 {
226         int rc = -ENOMEM;
227
228         ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
229                 (void *)(unsigned long)ps_tsk_num,
230                 "power_saving/%d", ps_tsk_num);
231         rc = IS_ERR(ps_tsks[ps_tsk_num]) ? PTR_ERR(ps_tsks[ps_tsk_num]) : 0;
232         if (!rc)
233                 ps_tsk_num++;
234         else
235                 ps_tsks[ps_tsk_num] = NULL;
236
237         return rc;
238 }
239
240 static void destroy_power_saving_task(void)
241 {
242         if (ps_tsk_num > 0) {
243                 ps_tsk_num--;
244                 kthread_stop(ps_tsks[ps_tsk_num]);
245                 ps_tsks[ps_tsk_num] = NULL;
246         }
247 }
248
249 static void set_power_saving_task_num(unsigned int num)
250 {
251         if (num > ps_tsk_num) {
252                 while (ps_tsk_num < num) {
253                         if (create_power_saving_task())
254                                 return;
255                 }
256         } else if (num < ps_tsk_num) {
257                 while (ps_tsk_num > num)
258                         destroy_power_saving_task();
259         }
260 }
261
262 static void acpi_pad_idle_cpus(unsigned int num_cpus)
263 {
264         get_online_cpus();
265
266         num_cpus = min_t(unsigned int, num_cpus, num_online_cpus());
267         set_power_saving_task_num(num_cpus);
268
269         put_online_cpus();
270 }
271
272 static uint32_t acpi_pad_idle_cpus_num(void)
273 {
274         return ps_tsk_num;
275 }
276
277 static ssize_t acpi_pad_rrtime_store(struct device *dev,
278         struct device_attribute *attr, const char *buf, size_t count)
279 {
280         unsigned long num;
281         if (strict_strtoul(buf, 0, &num))
282                 return -EINVAL;
283         if (num < 1 || num >= 100)
284                 return -EINVAL;
285         mutex_lock(&isolated_cpus_lock);
286         round_robin_time = num;
287         mutex_unlock(&isolated_cpus_lock);
288         return count;
289 }
290
291 static ssize_t acpi_pad_rrtime_show(struct device *dev,
292         struct device_attribute *attr, char *buf)
293 {
294         return scnprintf(buf, PAGE_SIZE, "%d", round_robin_time);
295 }
296 static DEVICE_ATTR(rrtime, S_IRUGO|S_IWUSR,
297         acpi_pad_rrtime_show,
298         acpi_pad_rrtime_store);
299
300 static ssize_t acpi_pad_idlepct_store(struct device *dev,
301         struct device_attribute *attr, const char *buf, size_t count)
302 {
303         unsigned long num;
304         if (strict_strtoul(buf, 0, &num))
305                 return -EINVAL;
306         if (num < 1 || num >= 100)
307                 return -EINVAL;
308         mutex_lock(&isolated_cpus_lock);
309         idle_pct = num;
310         mutex_unlock(&isolated_cpus_lock);
311         return count;
312 }
313
314 static ssize_t acpi_pad_idlepct_show(struct device *dev,
315         struct device_attribute *attr, char *buf)
316 {
317         return scnprintf(buf, PAGE_SIZE, "%d", idle_pct);
318 }
319 static DEVICE_ATTR(idlepct, S_IRUGO|S_IWUSR,
320         acpi_pad_idlepct_show,
321         acpi_pad_idlepct_store);
322
323 static ssize_t acpi_pad_idlecpus_store(struct device *dev,
324         struct device_attribute *attr, const char *buf, size_t count)
325 {
326         unsigned long num;
327         if (strict_strtoul(buf, 0, &num))
328                 return -EINVAL;
329         mutex_lock(&isolated_cpus_lock);
330         acpi_pad_idle_cpus(num);
331         mutex_unlock(&isolated_cpus_lock);
332         return count;
333 }
334
335 static ssize_t acpi_pad_idlecpus_show(struct device *dev,
336         struct device_attribute *attr, char *buf)
337 {
338         return cpumask_scnprintf(buf, PAGE_SIZE,
339                 to_cpumask(pad_busy_cpus_bits));
340 }
341 static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR,
342         acpi_pad_idlecpus_show,
343         acpi_pad_idlecpus_store);
344
345 static int acpi_pad_add_sysfs(struct acpi_device *device)
346 {
347         int result;
348
349         result = device_create_file(&device->dev, &dev_attr_idlecpus);
350         if (result)
351                 return -ENODEV;
352         result = device_create_file(&device->dev, &dev_attr_idlepct);
353         if (result) {
354                 device_remove_file(&device->dev, &dev_attr_idlecpus);
355                 return -ENODEV;
356         }
357         result = device_create_file(&device->dev, &dev_attr_rrtime);
358         if (result) {
359                 device_remove_file(&device->dev, &dev_attr_idlecpus);
360                 device_remove_file(&device->dev, &dev_attr_idlepct);
361                 return -ENODEV;
362         }
363         return 0;
364 }
365
366 static void acpi_pad_remove_sysfs(struct acpi_device *device)
367 {
368         device_remove_file(&device->dev, &dev_attr_idlecpus);
369         device_remove_file(&device->dev, &dev_attr_idlepct);
370         device_remove_file(&device->dev, &dev_attr_rrtime);
371 }
372
373 /* Query firmware how many CPUs should be idle */
374 static int acpi_pad_pur(acpi_handle handle, int *num_cpus)
375 {
376         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
377         union acpi_object *package;
378         int rev, num, ret = -EINVAL;
379
380         if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
381                 return -EINVAL;
382
383         if (!buffer.length || !buffer.pointer)
384                 return -EINVAL;
385
386         package = buffer.pointer;
387         if (package->type != ACPI_TYPE_PACKAGE || package->package.count != 2)
388                 goto out;
389         rev = package->package.elements[0].integer.value;
390         num = package->package.elements[1].integer.value;
391         if (rev != 1 || num < 0)
392                 goto out;
393         *num_cpus = num;
394         ret = 0;
395 out:
396         kfree(buffer.pointer);
397         return ret;
398 }
399
400 /* Notify firmware how many CPUs are idle */
401 static void acpi_pad_ost(acpi_handle handle, int stat,
402         uint32_t idle_cpus)
403 {
404         union acpi_object params[3] = {
405                 {.type = ACPI_TYPE_INTEGER,},
406                 {.type = ACPI_TYPE_INTEGER,},
407                 {.type = ACPI_TYPE_BUFFER,},
408         };
409         struct acpi_object_list arg_list = {3, params};
410
411         params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
412         params[1].integer.value =  stat;
413         params[2].buffer.length = 4;
414         params[2].buffer.pointer = (void *)&idle_cpus;
415         acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
416 }
417
418 static void acpi_pad_handle_notify(acpi_handle handle)
419 {
420         int num_cpus;
421         uint32_t idle_cpus;
422
423         mutex_lock(&isolated_cpus_lock);
424         if (acpi_pad_pur(handle, &num_cpus)) {
425                 mutex_unlock(&isolated_cpus_lock);
426                 return;
427         }
428         acpi_pad_idle_cpus(num_cpus);
429         idle_cpus = acpi_pad_idle_cpus_num();
430         acpi_pad_ost(handle, 0, idle_cpus);
431         mutex_unlock(&isolated_cpus_lock);
432 }
433
434 static void acpi_pad_notify(acpi_handle handle, u32 event,
435         void *data)
436 {
437         struct acpi_device *device = data;
438
439         switch (event) {
440         case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
441                 acpi_pad_handle_notify(handle);
442                 acpi_bus_generate_proc_event(device, event, 0);
443                 acpi_bus_generate_netlink_event(device->pnp.device_class,
444                         dev_name(&device->dev), event, 0);
445                 break;
446         default:
447                 printk(KERN_WARNING"Unsupported event [0x%x]\n", event);
448                 break;
449         }
450 }
451
452 static int acpi_pad_add(struct acpi_device *device)
453 {
454         acpi_status status;
455
456         strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
457         strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
458
459         if (acpi_pad_add_sysfs(device))
460                 return -ENODEV;
461
462         status = acpi_install_notify_handler(device->handle,
463                 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
464         if (ACPI_FAILURE(status)) {
465                 acpi_pad_remove_sysfs(device);
466                 return -ENODEV;
467         }
468
469         return 0;
470 }
471
472 static int acpi_pad_remove(struct acpi_device *device,
473         int type)
474 {
475         mutex_lock(&isolated_cpus_lock);
476         acpi_pad_idle_cpus(0);
477         mutex_unlock(&isolated_cpus_lock);
478
479         acpi_remove_notify_handler(device->handle,
480                 ACPI_DEVICE_NOTIFY, acpi_pad_notify);
481         acpi_pad_remove_sysfs(device);
482         return 0;
483 }
484
485 static const struct acpi_device_id pad_device_ids[] = {
486         {"ACPI000C", 0},
487         {"", 0},
488 };
489 MODULE_DEVICE_TABLE(acpi, pad_device_ids);
490
491 static struct acpi_driver acpi_pad_driver = {
492         .name = "processor_aggregator",
493         .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
494         .ids = pad_device_ids,
495         .ops = {
496                 .add = acpi_pad_add,
497                 .remove = acpi_pad_remove,
498         },
499 };
500
501 static int __init acpi_pad_init(void)
502 {
503         power_saving_mwait_init();
504         if (power_saving_mwait_eax == 0)
505                 return -EINVAL;
506
507         return acpi_bus_register_driver(&acpi_pad_driver);
508 }
509
510 static void __exit acpi_pad_exit(void)
511 {
512         acpi_bus_unregister_driver(&acpi_pad_driver);
513 }
514
515 module_init(acpi_pad_init);
516 module_exit(acpi_pad_exit);
517 MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
518 MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
519 MODULE_LICENSE("GPL");