cpufreq: OMAP: notify even with bad boot frequency
[linux-2.6.git] / drivers / cpufreq / e_powersaver.c
1 /*
2  *  Based on documentation provided by Dave Jones. Thanks!
3  *
4  *  Licensed under the terms of the GNU GPL License version 2.
5  *
6  *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
7  */
8
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/cpufreq.h>
13 #include <linux/ioport.h>
14 #include <linux/slab.h>
15 #include <linux/timex.h>
16 #include <linux/io.h>
17 #include <linux/delay.h>
18
19 #include <asm/msr.h>
20 #include <asm/tsc.h>
21
22 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
23 #include <linux/acpi.h>
24 #include <acpi/processor.h>
25 #endif
26
27 #define EPS_BRAND_C7M   0
28 #define EPS_BRAND_C7    1
29 #define EPS_BRAND_EDEN  2
30 #define EPS_BRAND_C3    3
31 #define EPS_BRAND_C7D   4
32
33 struct eps_cpu_data {
34         u32 fsb;
35 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
36         u32 bios_limit;
37 #endif
38         struct cpufreq_frequency_table freq_table[];
39 };
40
41 static struct eps_cpu_data *eps_cpu[NR_CPUS];
42
43 /* Module parameters */
44 static int freq_failsafe_off;
45 static int voltage_failsafe_off;
46 static int set_max_voltage;
47
48 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
49 static int ignore_acpi_limit;
50
51 static struct acpi_processor_performance *eps_acpi_cpu_perf;
52
53 /* Minimum necessary to get acpi_processor_get_bios_limit() working */
54 static int eps_acpi_init(void)
55 {
56         eps_acpi_cpu_perf = kzalloc(sizeof(struct acpi_processor_performance),
57                                       GFP_KERNEL);
58         if (!eps_acpi_cpu_perf)
59                 return -ENOMEM;
60
61         if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
62                                                                 GFP_KERNEL)) {
63                 kfree(eps_acpi_cpu_perf);
64                 eps_acpi_cpu_perf = NULL;
65                 return -ENOMEM;
66         }
67
68         if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
69                 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
70                 kfree(eps_acpi_cpu_perf);
71                 eps_acpi_cpu_perf = NULL;
72                 return -EIO;
73         }
74         return 0;
75 }
76
77 static int eps_acpi_exit(struct cpufreq_policy *policy)
78 {
79         if (eps_acpi_cpu_perf) {
80                 acpi_processor_unregister_performance(eps_acpi_cpu_perf, 0);
81                 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
82                 kfree(eps_acpi_cpu_perf);
83                 eps_acpi_cpu_perf = NULL;
84         }
85         return 0;
86 }
87 #endif
88
89 static unsigned int eps_get(unsigned int cpu)
90 {
91         struct eps_cpu_data *centaur;
92         u32 lo, hi;
93
94         if (cpu)
95                 return 0;
96         centaur = eps_cpu[cpu];
97         if (centaur == NULL)
98                 return 0;
99
100         /* Return current frequency */
101         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
102         return centaur->fsb * ((lo >> 8) & 0xff);
103 }
104
105 static int eps_set_state(struct eps_cpu_data *centaur,
106                          unsigned int cpu,
107                          u32 dest_state)
108 {
109         struct cpufreq_freqs freqs;
110         u32 lo, hi;
111         int err = 0;
112         int i;
113
114         freqs.old = eps_get(cpu);
115         freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
116         freqs.cpu = cpu;
117         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
118
119         /* Wait while CPU is busy */
120         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
121         i = 0;
122         while (lo & ((1 << 16) | (1 << 17))) {
123                 udelay(16);
124                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
125                 i++;
126                 if (unlikely(i > 64)) {
127                         err = -ENODEV;
128                         goto postchange;
129                 }
130         }
131         /* Set new multiplier and voltage */
132         wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
133         /* Wait until transition end */
134         i = 0;
135         do {
136                 udelay(16);
137                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
138                 i++;
139                 if (unlikely(i > 64)) {
140                         err = -ENODEV;
141                         goto postchange;
142                 }
143         } while (lo & ((1 << 16) | (1 << 17)));
144
145         /* Return current frequency */
146 postchange:
147         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
148         freqs.new = centaur->fsb * ((lo >> 8) & 0xff);
149
150 #ifdef DEBUG
151         {
152         u8 current_multiplier, current_voltage;
153
154         /* Print voltage and multiplier */
155         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
156         current_voltage = lo & 0xff;
157         printk(KERN_INFO "eps: Current voltage = %dmV\n",
158                 current_voltage * 16 + 700);
159         current_multiplier = (lo >> 8) & 0xff;
160         printk(KERN_INFO "eps: Current multiplier = %d\n",
161                 current_multiplier);
162         }
163 #endif
164         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
165         return err;
166 }
167
168 static int eps_target(struct cpufreq_policy *policy,
169                                unsigned int target_freq,
170                                unsigned int relation)
171 {
172         struct eps_cpu_data *centaur;
173         unsigned int newstate = 0;
174         unsigned int cpu = policy->cpu;
175         unsigned int dest_state;
176         int ret;
177
178         if (unlikely(eps_cpu[cpu] == NULL))
179                 return -ENODEV;
180         centaur = eps_cpu[cpu];
181
182         if (unlikely(cpufreq_frequency_table_target(policy,
183                         &eps_cpu[cpu]->freq_table[0],
184                         target_freq,
185                         relation,
186                         &newstate))) {
187                 return -EINVAL;
188         }
189
190         /* Make frequency transition */
191         dest_state = centaur->freq_table[newstate].index & 0xffff;
192         ret = eps_set_state(centaur, cpu, dest_state);
193         if (ret)
194                 printk(KERN_ERR "eps: Timeout!\n");
195         return ret;
196 }
197
198 static int eps_verify(struct cpufreq_policy *policy)
199 {
200         return cpufreq_frequency_table_verify(policy,
201                         &eps_cpu[policy->cpu]->freq_table[0]);
202 }
203
204 static int eps_cpu_init(struct cpufreq_policy *policy)
205 {
206         unsigned int i;
207         u32 lo, hi;
208         u64 val;
209         u8 current_multiplier, current_voltage;
210         u8 max_multiplier, max_voltage;
211         u8 min_multiplier, min_voltage;
212         u8 brand = 0;
213         u32 fsb;
214         struct eps_cpu_data *centaur;
215         struct cpuinfo_x86 *c = &cpu_data(0);
216         struct cpufreq_frequency_table *f_table;
217         int k, step, voltage;
218         int ret;
219         int states;
220 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
221         unsigned int limit;
222 #endif
223
224         if (policy->cpu != 0)
225                 return -ENODEV;
226
227         /* Check brand */
228         printk(KERN_INFO "eps: Detected VIA ");
229
230         switch (c->x86_model) {
231         case 10:
232                 rdmsr(0x1153, lo, hi);
233                 brand = (((lo >> 2) ^ lo) >> 18) & 3;
234                 printk(KERN_CONT "Model A ");
235                 break;
236         case 13:
237                 rdmsr(0x1154, lo, hi);
238                 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
239                 printk(KERN_CONT "Model D ");
240                 break;
241         }
242
243         switch (brand) {
244         case EPS_BRAND_C7M:
245                 printk(KERN_CONT "C7-M\n");
246                 break;
247         case EPS_BRAND_C7:
248                 printk(KERN_CONT "C7\n");
249                 break;
250         case EPS_BRAND_EDEN:
251                 printk(KERN_CONT "Eden\n");
252                 break;
253         case EPS_BRAND_C7D:
254                 printk(KERN_CONT "C7-D\n");
255                 break;
256         case EPS_BRAND_C3:
257                 printk(KERN_CONT "C3\n");
258                 return -ENODEV;
259                 break;
260         }
261         /* Enable Enhanced PowerSaver */
262         rdmsrl(MSR_IA32_MISC_ENABLE, val);
263         if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
264                 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
265                 wrmsrl(MSR_IA32_MISC_ENABLE, val);
266                 /* Can be locked at 0 */
267                 rdmsrl(MSR_IA32_MISC_ENABLE, val);
268                 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
269                         printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
270                         return -ENODEV;
271                 }
272         }
273
274         /* Print voltage and multiplier */
275         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
276         current_voltage = lo & 0xff;
277         printk(KERN_INFO "eps: Current voltage = %dmV\n",
278                         current_voltage * 16 + 700);
279         current_multiplier = (lo >> 8) & 0xff;
280         printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
281
282         /* Print limits */
283         max_voltage = hi & 0xff;
284         printk(KERN_INFO "eps: Highest voltage = %dmV\n",
285                         max_voltage * 16 + 700);
286         max_multiplier = (hi >> 8) & 0xff;
287         printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
288         min_voltage = (hi >> 16) & 0xff;
289         printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
290                         min_voltage * 16 + 700);
291         min_multiplier = (hi >> 24) & 0xff;
292         printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
293
294         /* Sanity checks */
295         if (current_multiplier == 0 || max_multiplier == 0
296             || min_multiplier == 0)
297                 return -EINVAL;
298         if (current_multiplier > max_multiplier
299             || max_multiplier <= min_multiplier)
300                 return -EINVAL;
301         if (current_voltage > 0x1f || max_voltage > 0x1f)
302                 return -EINVAL;
303         if (max_voltage < min_voltage
304             || current_voltage < min_voltage
305             || current_voltage > max_voltage)
306                 return -EINVAL;
307
308         /* Check for systems using underclocked CPU */
309         if (!freq_failsafe_off && max_multiplier != current_multiplier) {
310                 printk(KERN_INFO "eps: Your processor is running at different "
311                         "frequency then its maximum. Aborting.\n");
312                 printk(KERN_INFO "eps: You can use freq_failsafe_off option "
313                         "to disable this check.\n");
314                 return -EINVAL;
315         }
316         if (!voltage_failsafe_off && max_voltage != current_voltage) {
317                 printk(KERN_INFO "eps: Your processor is running at different "
318                         "voltage then its maximum. Aborting.\n");
319                 printk(KERN_INFO "eps: You can use voltage_failsafe_off "
320                         "option to disable this check.\n");
321                 return -EINVAL;
322         }
323
324         /* Calc FSB speed */
325         fsb = cpu_khz / current_multiplier;
326
327 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
328         /* Check for ACPI processor speed limit */
329         if (!ignore_acpi_limit && !eps_acpi_init()) {
330                 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
331                         printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
332                                 limit/1000000,
333                                 (limit%1000000)/10000);
334                         eps_acpi_exit(policy);
335                         /* Check if max_multiplier is in BIOS limits */
336                         if (limit && max_multiplier * fsb > limit) {
337                                 printk(KERN_INFO "eps: Aborting.\n");
338                                 return -EINVAL;
339                         }
340                 }
341         }
342 #endif
343
344         /* Allow user to set lower maximum voltage then that reported
345          * by processor */
346         if (brand == EPS_BRAND_C7M && set_max_voltage) {
347                 u32 v;
348
349                 /* Change mV to something hardware can use */
350                 v = (set_max_voltage - 700) / 16;
351                 /* Check if voltage is within limits */
352                 if (v >= min_voltage && v <= max_voltage) {
353                         printk(KERN_INFO "eps: Setting %dmV as maximum.\n",
354                                 v * 16 + 700);
355                         max_voltage = v;
356                 }
357         }
358
359         /* Calc number of p-states supported */
360         if (brand == EPS_BRAND_C7M)
361                 states = max_multiplier - min_multiplier + 1;
362         else
363                 states = 2;
364
365         /* Allocate private data and frequency table for current cpu */
366         centaur = kzalloc(sizeof(struct eps_cpu_data)
367                     + (states + 1) * sizeof(struct cpufreq_frequency_table),
368                     GFP_KERNEL);
369         if (!centaur)
370                 return -ENOMEM;
371         eps_cpu[0] = centaur;
372
373         /* Copy basic values */
374         centaur->fsb = fsb;
375 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
376         centaur->bios_limit = limit;
377 #endif
378
379         /* Fill frequency and MSR value table */
380         f_table = &centaur->freq_table[0];
381         if (brand != EPS_BRAND_C7M) {
382                 f_table[0].frequency = fsb * min_multiplier;
383                 f_table[0].index = (min_multiplier << 8) | min_voltage;
384                 f_table[1].frequency = fsb * max_multiplier;
385                 f_table[1].index = (max_multiplier << 8) | max_voltage;
386                 f_table[2].frequency = CPUFREQ_TABLE_END;
387         } else {
388                 k = 0;
389                 step = ((max_voltage - min_voltage) * 256)
390                         / (max_multiplier - min_multiplier);
391                 for (i = min_multiplier; i <= max_multiplier; i++) {
392                         voltage = (k * step) / 256 + min_voltage;
393                         f_table[k].frequency = fsb * i;
394                         f_table[k].index = (i << 8) | voltage;
395                         k++;
396                 }
397                 f_table[k].frequency = CPUFREQ_TABLE_END;
398         }
399
400         policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
401         policy->cur = fsb * current_multiplier;
402
403         ret = cpufreq_frequency_table_cpuinfo(policy, &centaur->freq_table[0]);
404         if (ret) {
405                 kfree(centaur);
406                 return ret;
407         }
408
409         cpufreq_frequency_table_get_attr(&centaur->freq_table[0], policy->cpu);
410         return 0;
411 }
412
413 static int eps_cpu_exit(struct cpufreq_policy *policy)
414 {
415         unsigned int cpu = policy->cpu;
416
417         /* Bye */
418         cpufreq_frequency_table_put_attr(policy->cpu);
419         kfree(eps_cpu[cpu]);
420         eps_cpu[cpu] = NULL;
421         return 0;
422 }
423
424 static struct freq_attr *eps_attr[] = {
425         &cpufreq_freq_attr_scaling_available_freqs,
426         NULL,
427 };
428
429 static struct cpufreq_driver eps_driver = {
430         .verify         = eps_verify,
431         .target         = eps_target,
432         .init           = eps_cpu_init,
433         .exit           = eps_cpu_exit,
434         .get            = eps_get,
435         .name           = "e_powersaver",
436         .owner          = THIS_MODULE,
437         .attr           = eps_attr,
438 };
439
440 static int __init eps_init(void)
441 {
442         struct cpuinfo_x86 *c = &cpu_data(0);
443
444         /* This driver will work only on Centaur C7 processors with
445          * Enhanced SpeedStep/PowerSaver registers */
446         if (c->x86_vendor != X86_VENDOR_CENTAUR
447             || c->x86 != 6 || c->x86_model < 10)
448                 return -ENODEV;
449         if (!cpu_has(c, X86_FEATURE_EST))
450                 return -ENODEV;
451
452         if (cpufreq_register_driver(&eps_driver))
453                 return -EINVAL;
454         return 0;
455 }
456
457 static void __exit eps_exit(void)
458 {
459         cpufreq_unregister_driver(&eps_driver);
460 }
461
462 /* Allow user to overclock his machine or to change frequency to higher after
463  * unloading module */
464 module_param(freq_failsafe_off, int, 0644);
465 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
466 module_param(voltage_failsafe_off, int, 0644);
467 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
468 #if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
469 module_param(ignore_acpi_limit, int, 0644);
470 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
471 #endif
472 module_param(set_max_voltage, int, 0644);
473 MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
474
475 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
476 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
477 MODULE_LICENSE("GPL");
478
479 module_init(eps_init);
480 module_exit(eps_exit);