Revert "ARM: tegra: tegratab: dummy change"
[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 static DEFINE_MUTEX(round_robin_lock);
40
41 static unsigned long power_saving_mwait_eax;
42
43 static unsigned char tsc_detected_unstable;
44 static unsigned char tsc_marked_unstable;
45 static unsigned char lapic_detected_unstable;
46 static unsigned char lapic_marked_unstable;
47
48 static void power_saving_mwait_init(void)
49 {
50         unsigned int eax, ebx, ecx, edx;
51         unsigned int highest_cstate = 0;
52         unsigned int highest_subcstate = 0;
53         int i;
54
55         if (!boot_cpu_has(X86_FEATURE_MWAIT))
56                 return;
57         if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
58                 return;
59
60         cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
61
62         if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
63             !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
64                 return;
65
66         edx >>= MWAIT_SUBSTATE_SIZE;
67         for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
68                 if (edx & MWAIT_SUBSTATE_MASK) {
69                         highest_cstate = i;
70                         highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
71                 }
72         }
73         power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
74                 (highest_subcstate - 1);
75
76 #if 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                         tsc_detected_unstable = 1;
86                 if (!boot_cpu_has(X86_FEATURE_ARAT))
87                         lapic_detected_unstable = 1;
88                 break;
89         default:
90                 /* TSC & LAPIC could halt in idle */
91                 tsc_detected_unstable = 1;
92                 lapic_detected_unstable = 1;
93         }
94 #endif
95 }
96
97 static unsigned long cpu_weight[NR_CPUS];
98 static int tsk_in_cpu[NR_CPUS] = {[0 ... NR_CPUS-1] = -1};
99 static DECLARE_BITMAP(pad_busy_cpus_bits, NR_CPUS);
100 static void round_robin_cpu(unsigned int tsk_index)
101 {
102         struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
103         cpumask_var_t tmp;
104         int cpu;
105         unsigned long min_weight = -1;
106         unsigned long uninitialized_var(preferred_cpu);
107
108         if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
109                 return;
110
111         mutex_lock(&round_robin_lock);
112         cpumask_clear(tmp);
113         for_each_cpu(cpu, pad_busy_cpus)
114                 cpumask_or(tmp, tmp, topology_thread_cpumask(cpu));
115         cpumask_andnot(tmp, cpu_online_mask, tmp);
116         /* avoid HT sibilings if possible */
117         if (cpumask_empty(tmp))
118                 cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
119         if (cpumask_empty(tmp)) {
120                 mutex_unlock(&round_robin_lock);
121                 return;
122         }
123         for_each_cpu(cpu, tmp) {
124                 if (cpu_weight[cpu] < min_weight) {
125                         min_weight = cpu_weight[cpu];
126                         preferred_cpu = cpu;
127                 }
128         }
129
130         if (tsk_in_cpu[tsk_index] != -1)
131                 cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
132         tsk_in_cpu[tsk_index] = preferred_cpu;
133         cpumask_set_cpu(preferred_cpu, pad_busy_cpus);
134         cpu_weight[preferred_cpu]++;
135         mutex_unlock(&round_robin_lock);
136
137         set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
138 }
139
140 static void exit_round_robin(unsigned int tsk_index)
141 {
142         struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
143         cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
144         tsk_in_cpu[tsk_index] = -1;
145 }
146
147 static unsigned int idle_pct = 5; /* percentage */
148 static unsigned int round_robin_time = 10; /* second */
149 static int power_saving_thread(void *data)
150 {
151         struct sched_param param = {.sched_priority = 1};
152         int do_sleep;
153         unsigned int tsk_index = (unsigned long)data;
154         u64 last_jiffies = 0;
155
156         sched_setscheduler(current, SCHED_RR, &param);
157
158         while (!kthread_should_stop()) {
159                 int cpu;
160                 u64 expire_time;
161
162                 try_to_freeze();
163
164                 /* round robin to cpus */
165                 if (last_jiffies + round_robin_time * HZ < jiffies) {
166                         last_jiffies = jiffies;
167                         round_robin_cpu(tsk_index);
168                 }
169
170                 do_sleep = 0;
171
172                 expire_time = jiffies + HZ * (100 - idle_pct) / 100;
173
174                 while (!need_resched()) {
175                         if (tsc_detected_unstable && !tsc_marked_unstable) {
176                                 /* TSC could halt in idle, so notify users */
177                                 mark_tsc_unstable("TSC halts in idle");
178                                 tsc_marked_unstable = 1;
179                         }
180                         if (lapic_detected_unstable && !lapic_marked_unstable) {
181                                 int i;
182                                 /* LAPIC could halt in idle, so notify users */
183                                 for_each_online_cpu(i)
184                                         clockevents_notify(
185                                                 CLOCK_EVT_NOTIFY_BROADCAST_ON,
186                                                 &i);
187                                 lapic_marked_unstable = 1;
188                         }
189                         local_irq_disable();
190                         cpu = smp_processor_id();
191                         if (lapic_marked_unstable)
192                                 clockevents_notify(
193                                         CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
194                         stop_critical_timings();
195
196                         __monitor((void *)&current_thread_info()->flags, 0, 0);
197                         smp_mb();
198                         if (!need_resched())
199                                 __mwait(power_saving_mwait_eax, 1);
200
201                         start_critical_timings();
202                         if (lapic_marked_unstable)
203                                 clockevents_notify(
204                                         CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
205                         local_irq_enable();
206
207                         if (jiffies > expire_time) {
208                                 do_sleep = 1;
209                                 break;
210                         }
211                 }
212
213                 /*
214                  * current sched_rt has threshold for rt task running time.
215                  * When a rt task uses 95% CPU time, the rt thread will be
216                  * scheduled out for 5% CPU time to not starve other tasks. But
217                  * the mechanism only works when all CPUs have RT task running,
218                  * as if one CPU hasn't RT task, RT task from other CPUs will
219                  * borrow CPU time from this CPU and cause RT task use > 95%
220                  * CPU time. To make 'avoid starvation' work, takes a nap here.
221                  */
222                 if (do_sleep)
223                         schedule_timeout_killable(HZ * idle_pct / 100);
224         }
225
226         exit_round_robin(tsk_index);
227         return 0;
228 }
229
230 static struct task_struct *ps_tsks[NR_CPUS];
231 static unsigned int ps_tsk_num;
232 static int create_power_saving_task(void)
233 {
234         int rc = -ENOMEM;
235
236         ps_tsks[ps_tsk_num] = kthread_run(power_saving_thread,
237                 (void *)(unsigned long)ps_tsk_num,
238                 "power_saving/%d", ps_tsk_num);
239         rc = IS_ERR(ps_tsks[ps_tsk_num]) ? PTR_ERR(ps_tsks[ps_tsk_num]) : 0;
240         if (!rc)
241                 ps_tsk_num++;
242         else
243                 ps_tsks[ps_tsk_num] = NULL;
244
245         return rc;
246 }
247
248 static void destroy_power_saving_task(void)
249 {
250         if (ps_tsk_num > 0) {
251                 ps_tsk_num--;
252                 kthread_stop(ps_tsks[ps_tsk_num]);
253                 ps_tsks[ps_tsk_num] = NULL;
254         }
255 }
256
257 static void set_power_saving_task_num(unsigned int num)
258 {
259         if (num > ps_tsk_num) {
260                 while (ps_tsk_num < num) {
261                         if (create_power_saving_task())
262                                 return;
263                 }
264         } else if (num < ps_tsk_num) {
265                 while (ps_tsk_num > num)
266                         destroy_power_saving_task();
267         }
268 }
269
270 static void acpi_pad_idle_cpus(unsigned int num_cpus)
271 {
272         get_online_cpus();
273
274         num_cpus = min_t(unsigned int, num_cpus, num_online_cpus());
275         set_power_saving_task_num(num_cpus);
276
277         put_online_cpus();
278 }
279
280 static uint32_t acpi_pad_idle_cpus_num(void)
281 {
282         return ps_tsk_num;
283 }
284
285 static ssize_t acpi_pad_rrtime_store(struct device *dev,
286         struct device_attribute *attr, const char *buf, size_t count)
287 {
288         unsigned long num;
289         if (strict_strtoul(buf, 0, &num))
290                 return -EINVAL;
291         if (num < 1 || num >= 100)
292                 return -EINVAL;
293         mutex_lock(&isolated_cpus_lock);
294         round_robin_time = num;
295         mutex_unlock(&isolated_cpus_lock);
296         return count;
297 }
298
299 static ssize_t acpi_pad_rrtime_show(struct device *dev,
300         struct device_attribute *attr, char *buf)
301 {
302         return scnprintf(buf, PAGE_SIZE, "%d\n", round_robin_time);
303 }
304 static DEVICE_ATTR(rrtime, S_IRUGO|S_IWUSR,
305         acpi_pad_rrtime_show,
306         acpi_pad_rrtime_store);
307
308 static ssize_t acpi_pad_idlepct_store(struct device *dev,
309         struct device_attribute *attr, const char *buf, size_t count)
310 {
311         unsigned long num;
312         if (strict_strtoul(buf, 0, &num))
313                 return -EINVAL;
314         if (num < 1 || num >= 100)
315                 return -EINVAL;
316         mutex_lock(&isolated_cpus_lock);
317         idle_pct = num;
318         mutex_unlock(&isolated_cpus_lock);
319         return count;
320 }
321
322 static ssize_t acpi_pad_idlepct_show(struct device *dev,
323         struct device_attribute *attr, char *buf)
324 {
325         return scnprintf(buf, PAGE_SIZE, "%d\n", idle_pct);
326 }
327 static DEVICE_ATTR(idlepct, S_IRUGO|S_IWUSR,
328         acpi_pad_idlepct_show,
329         acpi_pad_idlepct_store);
330
331 static ssize_t acpi_pad_idlecpus_store(struct device *dev,
332         struct device_attribute *attr, const char *buf, size_t count)
333 {
334         unsigned long num;
335         if (strict_strtoul(buf, 0, &num))
336                 return -EINVAL;
337         mutex_lock(&isolated_cpus_lock);
338         acpi_pad_idle_cpus(num);
339         mutex_unlock(&isolated_cpus_lock);
340         return count;
341 }
342
343 static ssize_t acpi_pad_idlecpus_show(struct device *dev,
344         struct device_attribute *attr, char *buf)
345 {
346         int n = 0;
347         n = cpumask_scnprintf(buf, PAGE_SIZE-2, to_cpumask(pad_busy_cpus_bits));
348         buf[n++] = '\n';
349         buf[n] = '\0';
350         return n;
351 }
352 static DEVICE_ATTR(idlecpus, S_IRUGO|S_IWUSR,
353         acpi_pad_idlecpus_show,
354         acpi_pad_idlecpus_store);
355
356 static int acpi_pad_add_sysfs(struct acpi_device *device)
357 {
358         int result;
359
360         result = device_create_file(&device->dev, &dev_attr_idlecpus);
361         if (result)
362                 return -ENODEV;
363         result = device_create_file(&device->dev, &dev_attr_idlepct);
364         if (result) {
365                 device_remove_file(&device->dev, &dev_attr_idlecpus);
366                 return -ENODEV;
367         }
368         result = device_create_file(&device->dev, &dev_attr_rrtime);
369         if (result) {
370                 device_remove_file(&device->dev, &dev_attr_idlecpus);
371                 device_remove_file(&device->dev, &dev_attr_idlepct);
372                 return -ENODEV;
373         }
374         return 0;
375 }
376
377 static void acpi_pad_remove_sysfs(struct acpi_device *device)
378 {
379         device_remove_file(&device->dev, &dev_attr_idlecpus);
380         device_remove_file(&device->dev, &dev_attr_idlepct);
381         device_remove_file(&device->dev, &dev_attr_rrtime);
382 }
383
384 /*
385  * Query firmware how many CPUs should be idle
386  * return -1 on failure
387  */
388 static int acpi_pad_pur(acpi_handle handle)
389 {
390         struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
391         union acpi_object *package;
392         int num = -1;
393
394         if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
395                 return num;
396
397         if (!buffer.length || !buffer.pointer)
398                 return num;
399
400         package = buffer.pointer;
401
402         if (package->type == ACPI_TYPE_PACKAGE &&
403                 package->package.count == 2 &&
404                 package->package.elements[0].integer.value == 1) /* rev 1 */
405
406                 num = package->package.elements[1].integer.value;
407
408         kfree(buffer.pointer);
409         return num;
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         num_cpus = acpi_pad_pur(handle);
437         if (num_cpus < 0) {
438                 mutex_unlock(&isolated_cpus_lock);
439                 return;
440         }
441         acpi_pad_idle_cpus(num_cpus);
442         idle_cpus = acpi_pad_idle_cpus_num();
443         acpi_pad_ost(handle, 0, idle_cpus);
444         mutex_unlock(&isolated_cpus_lock);
445 }
446
447 static void acpi_pad_notify(acpi_handle handle, u32 event,
448         void *data)
449 {
450         struct acpi_device *device = data;
451
452         switch (event) {
453         case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
454                 acpi_pad_handle_notify(handle);
455                 acpi_bus_generate_proc_event(device, event, 0);
456                 acpi_bus_generate_netlink_event(device->pnp.device_class,
457                         dev_name(&device->dev), event, 0);
458                 break;
459         default:
460                 printk(KERN_WARNING "Unsupported event [0x%x]\n", event);
461                 break;
462         }
463 }
464
465 static int acpi_pad_add(struct acpi_device *device)
466 {
467         acpi_status status;
468
469         strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
470         strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
471
472         if (acpi_pad_add_sysfs(device))
473                 return -ENODEV;
474
475         status = acpi_install_notify_handler(device->handle,
476                 ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
477         if (ACPI_FAILURE(status)) {
478                 acpi_pad_remove_sysfs(device);
479                 return -ENODEV;
480         }
481
482         return 0;
483 }
484
485 static int acpi_pad_remove(struct acpi_device *device,
486         int type)
487 {
488         mutex_lock(&isolated_cpus_lock);
489         acpi_pad_idle_cpus(0);
490         mutex_unlock(&isolated_cpus_lock);
491
492         acpi_remove_notify_handler(device->handle,
493                 ACPI_DEVICE_NOTIFY, acpi_pad_notify);
494         acpi_pad_remove_sysfs(device);
495         return 0;
496 }
497
498 static const struct acpi_device_id pad_device_ids[] = {
499         {"ACPI000C", 0},
500         {"", 0},
501 };
502 MODULE_DEVICE_TABLE(acpi, pad_device_ids);
503
504 static struct acpi_driver acpi_pad_driver = {
505         .name = "processor_aggregator",
506         .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
507         .ids = pad_device_ids,
508         .ops = {
509                 .add = acpi_pad_add,
510                 .remove = acpi_pad_remove,
511         },
512 };
513
514 static int __init acpi_pad_init(void)
515 {
516         power_saving_mwait_init();
517         if (power_saving_mwait_eax == 0)
518                 return -EINVAL;
519
520         return acpi_bus_register_driver(&acpi_pad_driver);
521 }
522
523 static void __exit acpi_pad_exit(void)
524 {
525         acpi_bus_unregister_driver(&acpi_pad_driver);
526 }
527
528 module_init(acpi_pad_init);
529 module_exit(acpi_pad_exit);
530 MODULE_AUTHOR("Shaohua Li<shaohua.li@intel.com>");
531 MODULE_DESCRIPTION("ACPI Processor Aggregator Driver");
532 MODULE_LICENSE("GPL");