time: Kill off CONFIG_GENERIC_TIME
[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
34 #define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
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
47 static unsigned char tsc_detected_unstable;
48 static unsigned char tsc_marked_unstable;
49 static unsigned char lapic_detected_unstable;
50 static unsigned char lapic_marked_unstable;
51
52 static void power_saving_mwait_init(void)
53 {
54         unsigned int eax, ebx, ecx, edx;
55         unsigned int highest_cstate = 0;
56         unsigned int highest_subcstate = 0;
57         int i;
58
59         if (!boot_cpu_has(X86_FEATURE_MWAIT))
60                 return;
61         if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
62                 return;
63
64         cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
65
66         if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
67             !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
68                 return;
69
70         edx >>= MWAIT_SUBSTATE_SIZE;
71         for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
72                 if (edx & MWAIT_SUBSTATE_MASK) {
73                         highest_cstate = i;
74                         highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
75                 }
76         }
77         power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
78                 (highest_subcstate - 1);
79
80 #if defined(CONFIG_X86)
81         switch (boot_cpu_data.x86_vendor) {
82         case X86_VENDOR_AMD:
83         case X86_VENDOR_INTEL:
84                 /*
85                  * AMD Fam10h TSC will tick in all
86                  * C/P/S0/S1 states when this bit is set.
87                  */
88                 if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
89                         tsc_detected_unstable = 1;
90                 if (!boot_cpu_has(X86_FEATURE_ARAT))
91                         lapic_detected_unstable = 1;
92                 break;
93         default:
94                 /* TSC & LAPIC could halt in idle */
95                 tsc_detected_unstable = 1;
96                 lapic_detected_unstable = 1;
97         }
98 #endif
99 }
100
101 static unsigned long cpu_weight[NR_CPUS];
102 static int tsk_in_cpu[NR_CPUS] = {[0 ... NR_CPUS-1] = -1};
103 static DECLARE_BITMAP(pad_busy_cpus_bits, NR_CPUS);
104 static void round_robin_cpu(unsigned int tsk_index)
105 {
106         struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
107         cpumask_var_t tmp;
108         int cpu;
109         unsigned long min_weight = -1;
110         unsigned long uninitialized_var(preferred_cpu);
111
112         if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
113                 return;
114
115         mutex_lock(&isolated_cpus_lock);
116         cpumask_clear(tmp);
117         for_each_cpu(cpu, pad_busy_cpus)
118                 cpumask_or(tmp, tmp, topology_thread_cpumask(cpu));
119         cpumask_andnot(tmp, cpu_online_mask, tmp);
120         /* avoid HT sibilings if possible */
121         if (cpumask_empty(tmp))
122                 cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
123         if (cpumask_empty(tmp)) {
124                 mutex_unlock(&isolated_cpus_lock);
125                 return;
126         }
127         for_each_cpu(cpu, tmp) {
128                 if (cpu_weight[cpu] < min_weight) {
129                         min_weight = cpu_weight[cpu];
130                         preferred_cpu = cpu;
131                 }
132         }
133
134         if (tsk_in_cpu[tsk_index] != -1)
135                 cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
136         tsk_in_cpu[tsk_index] = preferred_cpu;
137         cpumask_set_cpu(preferred_cpu, pad_busy_cpus);
138         cpu_weight[preferred_cpu]++;
139         mutex_unlock(&isolated_cpus_lock);
140
141         set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
142 }
143
144 static void exit_round_robin(unsigned int tsk_index)
145 {
146         struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
147         cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
148         tsk_in_cpu[tsk_index] = -1;
149 }
150
151 static unsigned int idle_pct = 5; /* percentage */
152 static unsigned int round_robin_time = 10; /* second */
153 static int power_saving_thread(void *data)
154 {
155         struct sched_param param = {.sched_priority = 1};
156         int do_sleep;
157         unsigned int tsk_index = (unsigned long)data;
158         u64 last_jiffies = 0;
159
160         sched_setscheduler(current, SCHED_RR, &param);
161
162         while (!kthread_should_stop()) {
163                 int cpu;
164                 u64 expire_time;
165
166                 try_to_freeze();
167
168                 /* round robin to cpus */
169                 if (last_jiffies + round_robin_time * HZ < jiffies) {
170                         last_jiffies = jiffies;
171                         round_robin_cpu(tsk_index);
172                 }
173
174                 do_sleep = 0;
175
176                 expire_time = jiffies + HZ * (100 - idle_pct) / 100;
177
178                 while (!need_resched()) {
179                         if (tsc_detected_unstable && !tsc_marked_unstable) {
180                                 /* TSC could halt in idle, so notify users */
181                                 mark_tsc_unstable("TSC halts in idle");
182                                 tsc_marked_unstable = 1;
183                         }
184                         if (lapic_detected_unstable && !lapic_marked_unstable) {
185                                 int i;
186                                 /* LAPIC could halt in idle, so notify users */
187                                 for_each_online_cpu(i)
188                                         clockevents_notify(
189                                                 CLOCK_EVT_NOTIFY_BROADCAST_ON,
190                                                 &i);
191                                 lapic_marked_unstable = 1;
192                         }
193                         local_irq_disable();
194                         cpu = smp_processor_id();
195                         if (lapic_marked_unstable)
196                                 clockevents_notify(
197                                         CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
198                         stop_critical_timings();
199
200                         __monitor((void *)&current_thread_info()->flags, 0, 0);
201                         smp_mb();
202                         if (!need_resched())
203                                 __mwait(power_saving_mwait_eax, 1);
204
205                         start_critical_timings();
206                         if (lapic_marked_unstable)
207                                 clockevents_notify(
208                                         CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
209                         local_irq_enable();
210
211                         if (jiffies > expire_time) {
212                                 do_sleep = 1;
213                                 break;
214                         }
215                 }
216
217                 /*
218                  * current sched_rt has threshold for rt task running time.
219                  * When a rt task uses 95% CPU time, the rt thread will be
220                  * scheduled out for 5% CPU time to not starve other tasks. But
221                  * the mechanism only works when all CPUs have RT task running,
222                  * as if one CPU hasn't RT task, RT task from other CPUs will
223                  * borrow CPU time from this CPU and cause RT task use > 95%
224                  * CPU time. To make 'avoid starvation' work, takes a nap here.
225                  */
226                 if (do_sleep)
227                         schedule_timeout_killable(HZ * idle_pct / 100);
228         }
229
230         exit_round_robin(tsk_index);
231         return 0;
232 }
233
234 static struct task_struct *ps_tsks[NR_CPUS];
235 static unsigned int ps_tsk_num;
236 static int create_power_saving_task(void)
237 {
238         int rc = -ENOMEM;
239
240         ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
241                 (void *)(unsigned long)ps_tsk_num,
242                 "power_saving/%d", ps_tsk_num);
243         rc = IS_ERR(ps_tsks[ps_tsk_num]) ? PTR_ERR(ps_tsks[ps_tsk_num]) : 0;
244         if (!rc)
245                 ps_tsk_num++;
246         else
247                 ps_tsks[ps_tsk_num] = NULL;
248
249         return rc;
250 }
251
252 static void destroy_power_saving_task(void)
253 {
254         if (ps_tsk_num > 0) {
255                 ps_tsk_num--;
256                 kthread_stop(ps_tsks[ps_tsk_num]);
257                 ps_tsks[ps_tsk_num] = NULL;
258         }
259 }
260
261 static void set_power_saving_task_num(unsigned int num)
262 {
263         if (num > ps_tsk_num) {
264                 while (ps_tsk_num < num) {
265                         if (create_power_saving_task())
266                                 return;
267                 }
268         } else if (num < ps_tsk_num) {
269                 while (ps_tsk_num > num)
270                         destroy_power_saving_task();
271         }
272 }
273
274 static void acpi_pad_idle_cpus(unsigned int num_cpus)
275 {
276         get_online_cpus();
277
278         num_cpus = min_t(unsigned int, num_cpus, num_online_cpus());
279         set_power_saving_task_num(num_cpus);
280
281         put_online_cpus();
282 }
283
284 static uint32_t acpi_pad_idle_cpus_num(void)
285 {
286         return ps_tsk_num;
287 }
288
289 static ssize_t acpi_pad_rrtime_store(struct device *dev,
290         struct device_attribute *attr, const char *buf, size_t count)
291 {
292         unsigned long num;
293         if (strict_strtoul(buf, 0, &num))
294                 return -EINVAL;
295         if (num < 1 || num >= 100)
296                 return -EINVAL;
297         mutex_lock(&isolated_cpus_lock);
298         round_robin_time = num;
299         mutex_unlock(&isolated_cpus_lock);
300         return count;
301 }
302
303 static ssize_t acpi_pad_rrtime_show(struct device *dev,
304         struct device_attribute *attr, char *buf)
305 {
306         return scnprintf(buf, PAGE_SIZE, "%d", round_robin_time);
307 }
308 static DEVICE_ATTR(rrtime, S_IRUGO|S_IWUSR,
309         acpi_pad_rrtime_show,
310         acpi_pad_rrtime_store);
311
312 static ssize_t acpi_pad_idlepct_store(struct device *dev,
313         struct device_attribute *attr, const char *buf, size_t count)
314 {
315         unsigned long num;
316         if (strict_strtoul(buf, 0, &num))
317                 return -EINVAL;
318         if (num < 1 || num >= 100)
319                 return -EINVAL;
320         mutex_lock(&isolated_cpus_lock);
321         idle_pct = num;
322         mutex_unlock(&isolated_cpus_lock);
323         return count;
324 }
325
326 static ssize_t acpi_pad_idlepct_show(struct device *dev,
327         struct device_attribute *attr, char *buf)
328 {
329         return scnprintf(buf, PAGE_SIZE, "%d", idle_pct);
330 }
331 static DEVICE_ATTR(idlepct, S_IRUGO|S_IWUSR,
332         acpi_pad_idlepct_show,
333         acpi_pad_idlepct_store);
334
335 static ssize_t acpi_pad_idlecpus_store(struct device *dev,
336         struct device_attribute *attr, const char *buf, size_t count)
337 {
338         unsigned long num;
339         if (strict_strtoul(buf, 0, &num))
340                 return -EINVAL;
341         mutex_lock(&isolated_cpus_lock);
342         acpi_pad_idle_cpus(num);
343         mutex_unlock(&isolated_cpus_lock);
344         return count;
345 }
346
347 static ssize_t acpi_pad_idlecpus_show(struct device *dev,
348         struct device_attribute *attr, char *buf)
349 {
350         return cpumask_scnprintf(buf, PAGE_SIZE,
351                 to_cpumask(pad_busy_cpus_bits));
352 }
353 static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR,
354         acpi_pad_idlecpus_show,
355         acpi_pad_idlecpus_store);
356
357 static int acpi_pad_add_sysfs(struct acpi_device *device)
358 {
359         int result;
360
361         result = device_create_file(&device->dev, &dev_attr_idlecpus);
362         if (result)
363                 return -ENODEV;
364         result = device_create_file(&device->dev, &dev_attr_idlepct);
365         if (result) {
366                 device_remove_file(&device->dev, &dev_attr_idlecpus);
367                 return -ENODEV;
368         }
369         result = device_create_file(&device->dev, &dev_attr_rrtime);
370         if (result) {
371                 device_remove_file(&device->dev, &dev_attr_idlecpus);
372                 device_remove_file(&device->dev, &dev_attr_idlepct);
373                 return -ENODEV;
374         }
375         return 0;
376 }
377
378 static void acpi_pad_remove_sysfs(struct acpi_device *device)
379 {
380         device_remove_file(&device->dev, &dev_attr_idlecpus);
381         device_remove_file(&device->dev, &dev_attr_idlepct);
382         device_remove_file(&device->dev, &dev_attr_rrtime);
383 }
384
385 /* Query firmware how many CPUs should be idle */
386 static int acpi_pad_pur(acpi_handle handle, int *num_cpus)
387 {
388         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
389         union acpi_object *package;
390         int rev, num, ret = -EINVAL;
391
392         if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
393                 return -EINVAL;
394
395         if (!buffer.length || !buffer.pointer)
396                 return -EINVAL;
397
398         package = buffer.pointer;
399         if (package->type != ACPI_TYPE_PACKAGE || package->package.count != 2)
400                 goto out;
401         rev = package->package.elements[0].integer.value;
402         num = package->package.elements[1].integer.value;
403         if (rev != 1 || num < 0)
404                 goto out;
405         *num_cpus = num;
406         ret = 0;
407 out:
408         kfree(buffer.pointer);
409         return ret;
410 }
411
412 /* Notify firmware how many CPUs are idle */
413 static void acpi_pad_ost(acpi_handle handle, int stat,
414         uint32_t idle_cpus)
415 {
416         union acpi_object params[3] = {
417                 {.type = ACPI_TYPE_INTEGER,},
418                 {.type = ACPI_TYPE_INTEGER,},
419                 {.type = ACPI_TYPE_BUFFER,},
420         };
421         struct acpi_object_list arg_list = {3, params};
422
423         params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
424         params[1].integer.value =  stat;
425         params[2].buffer.length = 4;
426         params[2].buffer.pointer = (void *)&idle_cpus;
427         acpi_evaluate_object(handle, "_OST", &arg_list, NULL);
428 }
429
430 static void acpi_pad_handle_notify(acpi_handle handle)
431 {
432         int num_cpus;
433         uint32_t idle_cpus;
434
435         mutex_lock(&isolated_cpus_lock);
436         if (acpi_pad_pur(handle, &num_cpus)) {
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
446 static 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_proc_event(device, event, 0);
455                 acpi_bus_generate_netlink_event(device->pnp.device_class,
456                         dev_name(&device->dev), event, 0);
457                 break;
458         default:
459                 printk(KERN_WARNING"Unsupported event [0x%x]\n", event);
460                 break;
461         }
462 }
463
464 static int acpi_pad_add(struct acpi_device *device)
465 {
466         acpi_status status;
467
468         strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
469         strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
470
471         if (acpi_pad_add_sysfs(device))
472                 return -ENODEV;
473
474         status = acpi_install_notify_handler(device->handle,
475                 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
476         if (ACPI_FAILURE(status)) {
477                 acpi_pad_remove_sysfs(device);
478                 return -ENODEV;
479         }
480
481         return 0;
482 }
483
484 static int acpi_pad_remove(struct acpi_device *device,
485         int type)
486 {
487         mutex_lock(&isolated_cpus_lock);
488         acpi_pad_idle_cpus(0);
489         mutex_unlock(&isolated_cpus_lock);
490
491         acpi_remove_notify_handler(device->handle,
492                 ACPI_DEVICE_NOTIFY, acpi_pad_notify);
493         acpi_pad_remove_sysfs(device);
494         return 0;
495 }
496
497 static const struct acpi_device_id pad_device_ids[] = {
498         {"ACPI000C", 0},
499         {"", 0},
500 };
501 MODULE_DEVICE_TABLE(acpi, pad_device_ids);
502
503 static struct acpi_driver acpi_pad_driver = {
504         .name = "processor_aggregator",
505         .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
506         .ids = pad_device_ids,
507         .ops = {
508                 .add = acpi_pad_add,
509                 .remove = acpi_pad_remove,
510         },
511 };
512
513 static int __init acpi_pad_init(void)
514 {
515         power_saving_mwait_init();
516         if (power_saving_mwait_eax == 0)
517                 return -EINVAL;
518
519         return acpi_bus_register_driver(&acpi_pad_driver);
520 }
521
522 static void __exit acpi_pad_exit(void)
523 {
524         acpi_bus_unregister_driver(&acpi_pad_driver);
525 }
526
527 module_init(acpi_pad_init);
528 module_exit(acpi_pad_exit);
529 MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
530 MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
531 MODULE_LICENSE("GPL");