Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[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 <linux/slab.h>
31 #include <acpi/acpi_bus.h>
32 #include <acpi/acpi_drivers.h>
33 #include <asm/mwait.h>
34
35 #define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
36 #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
37 #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
38 static DEFINE_MUTEX(isolated_cpus_lock);
39
40 static unsigned long power_saving_mwait_eax;
41
42 static unsigned char tsc_detected_unstable;
43 static unsigned char tsc_marked_unstable;
44 static unsigned char lapic_detected_unstable;
45 static unsigned char lapic_marked_unstable;
46
47 static 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                  * AMD Fam10h TSC will tick in all
81                  * C/P/S0/S1 states when this bit is set.
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                 /* TSC & LAPIC could halt in idle */
90                 tsc_detected_unstable = 1;
91                 lapic_detected_unstable = 1;
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                 expire_time = jiffies + HZ * (100 - idle_pct) / 100;
172
173                 while (!need_resched()) {
174                         if (tsc_detected_unstable && !tsc_marked_unstable) {
175                                 /* TSC could halt in idle, so notify users */
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                                 /* LAPIC could halt in idle, so notify users */
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                         __monitor((void *)&current_thread_info()->flags, 0, 0);
196                         smp_mb();
197                         if (!need_resched())
198                                 __mwait(power_saving_mwait_eax, 1);
199
200                         start_critical_timings();
201                         if (lapic_marked_unstable)
202                                 clockevents_notify(
203                                         CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
204                         local_irq_enable();
205
206                         if (jiffies > expire_time) {
207                                 do_sleep = 1;
208                                 break;
209                         }
210                 }
211
212                 /*
213                  * current sched_rt has threshold for rt task running time.
214                  * When a rt task uses 95% CPU time, the rt thread will be
215                  * scheduled out for 5% CPU time to not starve other tasks. But
216                  * the mechanism only works when all CPUs have RT task running,
217                  * as if one CPU hasn't RT task, RT task from other CPUs will
218                  * borrow CPU time from this CPU and cause RT task use > 95%
219                  * CPU time. To make 'avoid starvation' work, takes a nap here.
220                  */
221                 if (do_sleep)
222                         schedule_timeout_killable(HZ * idle_pct / 100);
223         }
224
225         exit_round_robin(tsk_index);
226         return 0;
227 }
228
229 static struct task_struct *ps_tsks[NR_CPUS];
230 static unsigned int ps_tsk_num;
231 static int create_power_saving_task(void)
232 {
233         int rc = -ENOMEM;
234
235         ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
236                 (void *)(unsigned long)ps_tsk_num,
237                 "power_saving/%d", ps_tsk_num);
238         rc = IS_ERR(ps_tsks[ps_tsk_num]) ? PTR_ERR(ps_tsks[ps_tsk_num]) : 0;
239         if (!rc)
240                 ps_tsk_num++;
241         else
242                 ps_tsks[ps_tsk_num] = NULL;
243
244         return rc;
245 }
246
247 static 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
256 static 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
269 static 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
279 static uint32_t acpi_pad_idle_cpus_num(void)
280 {
281         return ps_tsk_num;
282 }
283
284 static 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 (strict_strtoul(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
298 static ssize_t acpi_pad_rrtime_show(struct device *dev,
299         struct device_attribute *attr, char *buf)
300 {
301         return scnprintf(buf, PAGE_SIZE, "%d", round_robin_time);
302 }
303 static DEVICE_ATTR(rrtime, S_IRUGO|S_IWUSR,
304         acpi_pad_rrtime_show,
305         acpi_pad_rrtime_store);
306
307 static 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 (strict_strtoul(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
321 static ssize_t acpi_pad_idlepct_show(struct device *dev,
322         struct device_attribute *attr, char *buf)
323 {
324         return scnprintf(buf, PAGE_SIZE, "%d", idle_pct);
325 }
326 static DEVICE_ATTR(idlepct, S_IRUGO|S_IWUSR,
327         acpi_pad_idlepct_show,
328         acpi_pad_idlepct_store);
329
330 static 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 (strict_strtoul(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
342 static ssize_t acpi_pad_idlecpus_show(struct device *dev,
343         struct device_attribute *attr, char *buf)
344 {
345         return cpumask_scnprintf(buf, PAGE_SIZE,
346                 to_cpumask(pad_busy_cpus_bits));
347 }
348 static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR,
349         acpi_pad_idlecpus_show,
350         acpi_pad_idlecpus_store);
351
352 static int acpi_pad_add_sysfs(struct acpi_device *device)
353 {
354         int result;
355
356         result = device_create_file(&device->dev, &dev_attr_idlecpus);
357         if (result)
358                 return -ENODEV;
359         result = device_create_file(&device->dev, &dev_attr_idlepct);
360         if (result) {
361                 device_remove_file(&device->dev, &dev_attr_idlecpus);
362                 return -ENODEV;
363         }
364         result = device_create_file(&device->dev, &dev_attr_rrtime);
365         if (result) {
366                 device_remove_file(&device->dev, &dev_attr_idlecpus);
367                 device_remove_file(&device->dev, &dev_attr_idlepct);
368                 return -ENODEV;
369         }
370         return 0;
371 }
372
373 static void acpi_pad_remove_sysfs(struct acpi_device *device)
374 {
375         device_remove_file(&device->dev, &dev_attr_idlecpus);
376         device_remove_file(&device->dev, &dev_attr_idlepct);
377         device_remove_file(&device->dev, &dev_attr_rrtime);
378 }
379
380 /*
381  * Query firmware how many CPUs should be idle
382  * return -1 on failure
383  */
384 static int acpi_pad_pur(acpi_handle handle)
385 {
386         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
387         union acpi_object *package;
388         int num = -1;
389
390         if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
391                 return num;
392
393         if (!buffer.length || !buffer.pointer)
394                 return num;
395
396         package = buffer.pointer;
397
398         if (package->type == ACPI_TYPE_PACKAGE &&
399                 package->package.count == 2 &&
400                 package->package.elements[0].integer.value == 1) /* rev 1 */
401
402                 num = package->package.elements[1].integer.value;
403
404         kfree(buffer.pointer);
405         return num;
406 }
407
408 /* Notify firmware how many CPUs are idle */
409 static void acpi_pad_ost(acpi_handle handle, int stat,
410         uint32_t idle_cpus)
411 {
412         union acpi_object params[3] = {
413                 {.type = ACPI_TYPE_INTEGER,},
414                 {.type = ACPI_TYPE_INTEGER,},
415                 {.type = ACPI_TYPE_BUFFER,},
416         };
417         struct acpi_object_list arg_list = {3, params};
418
419         params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
420         params[1].integer.value =  stat;
421         params[2].buffer.length = 4;
422         params[2].buffer.pointer = (void *)&idle_cpus;
423         acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
424 }
425
426 static void acpi_pad_handle_notify(acpi_handle handle)
427 {
428         int num_cpus;
429         uint32_t idle_cpus;
430
431         mutex_lock(&isolated_cpus_lock);
432         num_cpus = acpi_pad_pur(handle);
433         if (num_cpus < 0) {
434                 mutex_unlock(&isolated_cpus_lock);
435                 return;
436         }
437         acpi_pad_idle_cpus(num_cpus);
438         idle_cpus = acpi_pad_idle_cpus_num();
439         acpi_pad_ost(handle, 0, idle_cpus);
440         mutex_unlock(&isolated_cpus_lock);
441 }
442
443 static void acpi_pad_notify(acpi_handle handle, u32 event,
444         void *data)
445 {
446         struct acpi_device *device = data;
447
448         switch (event) {
449         case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
450                 acpi_pad_handle_notify(handle);
451                 acpi_bus_generate_proc_event(device, event, 0);
452                 acpi_bus_generate_netlink_event(device->pnp.device_class,
453                         dev_name(&device->dev), event, 0);
454                 break;
455         default:
456                 printk(KERN_WARNING"Unsupported event [0x%x]\n", event);
457                 break;
458         }
459 }
460
461 static int acpi_pad_add(struct acpi_device *device)
462 {
463         acpi_status status;
464
465         strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
466         strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
467
468         if (acpi_pad_add_sysfs(device))
469                 return -ENODEV;
470
471         status = acpi_install_notify_handler(device->handle,
472                 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
473         if (ACPI_FAILURE(status)) {
474                 acpi_pad_remove_sysfs(device);
475                 return -ENODEV;
476         }
477
478         return 0;
479 }
480
481 static int acpi_pad_remove(struct acpi_device *device,
482         int type)
483 {
484         mutex_lock(&isolated_cpus_lock);
485         acpi_pad_idle_cpus(0);
486         mutex_unlock(&isolated_cpus_lock);
487
488         acpi_remove_notify_handler(device->handle,
489                 ACPI_DEVICE_NOTIFY, acpi_pad_notify);
490         acpi_pad_remove_sysfs(device);
491         return 0;
492 }
493
494 static const struct acpi_device_id pad_device_ids[] = {
495         {"ACPI000C", 0},
496         {"", 0},
497 };
498 MODULE_DEVICE_TABLE(acpi, pad_device_ids);
499
500 static struct acpi_driver acpi_pad_driver = {
501         .name = "processor_aggregator",
502         .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
503         .ids = pad_device_ids,
504         .ops = {
505                 .add = acpi_pad_add,
506                 .remove = acpi_pad_remove,
507         },
508 };
509
510 static int __init acpi_pad_init(void)
511 {
512         power_saving_mwait_init();
513         if (power_saving_mwait_eax == 0)
514                 return -EINVAL;
515
516         return acpi_bus_register_driver(&acpi_pad_driver);
517 }
518
519 static void __exit acpi_pad_exit(void)
520 {
521         acpi_bus_unregister_driver(&acpi_pad_driver);
522 }
523
524 module_init(acpi_pad_init);
525 module_exit(acpi_pad_exit);
526 MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
527 MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
528 MODULE_LICENSE("GPL");