Merge branch 'gart/rename' of git://git.kernel.org/pub/scm/linux/kernel/git/joro...
[linux-2.6.git] / arch / x86 / kernel / cpu / 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 #define EPS_BRAND_C7M   0
23 #define EPS_BRAND_C7    1
24 #define EPS_BRAND_EDEN  2
25 #define EPS_BRAND_C3    3
26 #define EPS_BRAND_C7D   4
27
28 struct eps_cpu_data {
29         u32 fsb;
30         struct cpufreq_frequency_table freq_table[];
31 };
32
33 static struct eps_cpu_data *eps_cpu[NR_CPUS];
34
35
36 static unsigned int eps_get(unsigned int cpu)
37 {
38         struct eps_cpu_data *centaur;
39         u32 lo, hi;
40
41         if (cpu)
42                 return 0;
43         centaur = eps_cpu[cpu];
44         if (centaur == NULL)
45                 return 0;
46
47         /* Return current frequency */
48         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
49         return centaur->fsb * ((lo >> 8) & 0xff);
50 }
51
52 static int eps_set_state(struct eps_cpu_data *centaur,
53                          unsigned int cpu,
54                          u32 dest_state)
55 {
56         struct cpufreq_freqs freqs;
57         u32 lo, hi;
58         int err = 0;
59         int i;
60
61         freqs.old = eps_get(cpu);
62         freqs.new = centaur->fsb * ((dest_state >> 8) & 0xff);
63         freqs.cpu = cpu;
64         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
65
66         /* Wait while CPU is busy */
67         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
68         i = 0;
69         while (lo & ((1 << 16) | (1 << 17))) {
70                 udelay(16);
71                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
72                 i++;
73                 if (unlikely(i > 64)) {
74                         err = -ENODEV;
75                         goto postchange;
76                 }
77         }
78         /* Set new multiplier and voltage */
79         wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
80         /* Wait until transition end */
81         i = 0;
82         do {
83                 udelay(16);
84                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
85                 i++;
86                 if (unlikely(i > 64)) {
87                         err = -ENODEV;
88                         goto postchange;
89                 }
90         } while (lo & ((1 << 16) | (1 << 17)));
91
92         /* Return current frequency */
93 postchange:
94         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
95         freqs.new = centaur->fsb * ((lo >> 8) & 0xff);
96
97 #ifdef DEBUG
98         {
99         u8 current_multiplier, current_voltage;
100
101         /* Print voltage and multiplier */
102         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
103         current_voltage = lo & 0xff;
104         printk(KERN_INFO "eps: Current voltage = %dmV\n",
105                 current_voltage * 16 + 700);
106         current_multiplier = (lo >> 8) & 0xff;
107         printk(KERN_INFO "eps: Current multiplier = %d\n",
108                 current_multiplier);
109         }
110 #endif
111         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
112         return err;
113 }
114
115 static int eps_target(struct cpufreq_policy *policy,
116                                unsigned int target_freq,
117                                unsigned int relation)
118 {
119         struct eps_cpu_data *centaur;
120         unsigned int newstate = 0;
121         unsigned int cpu = policy->cpu;
122         unsigned int dest_state;
123         int ret;
124
125         if (unlikely(eps_cpu[cpu] == NULL))
126                 return -ENODEV;
127         centaur = eps_cpu[cpu];
128
129         if (unlikely(cpufreq_frequency_table_target(policy,
130                         &eps_cpu[cpu]->freq_table[0],
131                         target_freq,
132                         relation,
133                         &newstate))) {
134                 return -EINVAL;
135         }
136
137         /* Make frequency transition */
138         dest_state = centaur->freq_table[newstate].index & 0xffff;
139         ret = eps_set_state(centaur, cpu, dest_state);
140         if (ret)
141                 printk(KERN_ERR "eps: Timeout!\n");
142         return ret;
143 }
144
145 static int eps_verify(struct cpufreq_policy *policy)
146 {
147         return cpufreq_frequency_table_verify(policy,
148                         &eps_cpu[policy->cpu]->freq_table[0]);
149 }
150
151 static int eps_cpu_init(struct cpufreq_policy *policy)
152 {
153         unsigned int i;
154         u32 lo, hi;
155         u64 val;
156         u8 current_multiplier, current_voltage;
157         u8 max_multiplier, max_voltage;
158         u8 min_multiplier, min_voltage;
159         u8 brand = 0;
160         u32 fsb;
161         struct eps_cpu_data *centaur;
162         struct cpuinfo_x86 *c = &cpu_data(0);
163         struct cpufreq_frequency_table *f_table;
164         int k, step, voltage;
165         int ret;
166         int states;
167
168         if (policy->cpu != 0)
169                 return -ENODEV;
170
171         /* Check brand */
172         printk(KERN_INFO "eps: Detected VIA ");
173
174         switch (c->x86_model) {
175         case 10:
176                 rdmsr(0x1153, lo, hi);
177                 brand = (((lo >> 2) ^ lo) >> 18) & 3;
178                 printk(KERN_CONT "Model A ");
179                 break;
180         case 13:
181                 rdmsr(0x1154, lo, hi);
182                 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
183                 printk(KERN_CONT "Model D ");
184                 break;
185         }
186
187         switch (brand) {
188         case EPS_BRAND_C7M:
189                 printk(KERN_CONT "C7-M\n");
190                 break;
191         case EPS_BRAND_C7:
192                 printk(KERN_CONT "C7\n");
193                 break;
194         case EPS_BRAND_EDEN:
195                 printk(KERN_CONT "Eden\n");
196                 break;
197         case EPS_BRAND_C7D:
198                 printk(KERN_CONT "C7-D\n");
199                 break;
200         case EPS_BRAND_C3:
201                 printk(KERN_CONT "C3\n");
202                 return -ENODEV;
203                 break;
204         }
205         /* Enable Enhanced PowerSaver */
206         rdmsrl(MSR_IA32_MISC_ENABLE, val);
207         if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
208                 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
209                 wrmsrl(MSR_IA32_MISC_ENABLE, val);
210                 /* Can be locked at 0 */
211                 rdmsrl(MSR_IA32_MISC_ENABLE, val);
212                 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
213                         printk(KERN_INFO "eps: Can't enable Enhanced PowerSaver\n");
214                         return -ENODEV;
215                 }
216         }
217
218         /* Print voltage and multiplier */
219         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
220         current_voltage = lo & 0xff;
221         printk(KERN_INFO "eps: Current voltage = %dmV\n",
222                         current_voltage * 16 + 700);
223         current_multiplier = (lo >> 8) & 0xff;
224         printk(KERN_INFO "eps: Current multiplier = %d\n", current_multiplier);
225
226         /* Print limits */
227         max_voltage = hi & 0xff;
228         printk(KERN_INFO "eps: Highest voltage = %dmV\n",
229                         max_voltage * 16 + 700);
230         max_multiplier = (hi >> 8) & 0xff;
231         printk(KERN_INFO "eps: Highest multiplier = %d\n", max_multiplier);
232         min_voltage = (hi >> 16) & 0xff;
233         printk(KERN_INFO "eps: Lowest voltage = %dmV\n",
234                         min_voltage * 16 + 700);
235         min_multiplier = (hi >> 24) & 0xff;
236         printk(KERN_INFO "eps: Lowest multiplier = %d\n", min_multiplier);
237
238         /* Sanity checks */
239         if (current_multiplier == 0 || max_multiplier == 0
240             || min_multiplier == 0)
241                 return -EINVAL;
242         if (current_multiplier > max_multiplier
243             || max_multiplier <= min_multiplier)
244                 return -EINVAL;
245         if (current_voltage > 0x1f || max_voltage > 0x1f)
246                 return -EINVAL;
247         if (max_voltage < min_voltage)
248                 return -EINVAL;
249
250         /* Calc FSB speed */
251         fsb = cpu_khz / current_multiplier;
252         /* Calc number of p-states supported */
253         if (brand == EPS_BRAND_C7M)
254                 states = max_multiplier - min_multiplier + 1;
255         else
256                 states = 2;
257
258         /* Allocate private data and frequency table for current cpu */
259         centaur = kzalloc(sizeof(struct eps_cpu_data)
260                     + (states + 1) * sizeof(struct cpufreq_frequency_table),
261                     GFP_KERNEL);
262         if (!centaur)
263                 return -ENOMEM;
264         eps_cpu[0] = centaur;
265
266         /* Copy basic values */
267         centaur->fsb = fsb;
268
269         /* Fill frequency and MSR value table */
270         f_table = &centaur->freq_table[0];
271         if (brand != EPS_BRAND_C7M) {
272                 f_table[0].frequency = fsb * min_multiplier;
273                 f_table[0].index = (min_multiplier << 8) | min_voltage;
274                 f_table[1].frequency = fsb * max_multiplier;
275                 f_table[1].index = (max_multiplier << 8) | max_voltage;
276                 f_table[2].frequency = CPUFREQ_TABLE_END;
277         } else {
278                 k = 0;
279                 step = ((max_voltage - min_voltage) * 256)
280                         / (max_multiplier - min_multiplier);
281                 for (i = min_multiplier; i <= max_multiplier; i++) {
282                         voltage = (k * step) / 256 + min_voltage;
283                         f_table[k].frequency = fsb * i;
284                         f_table[k].index = (i << 8) | voltage;
285                         k++;
286                 }
287                 f_table[k].frequency = CPUFREQ_TABLE_END;
288         }
289
290         policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
291         policy->cur = fsb * current_multiplier;
292
293         ret = cpufreq_frequency_table_cpuinfo(policy, &centaur->freq_table[0]);
294         if (ret) {
295                 kfree(centaur);
296                 return ret;
297         }
298
299         cpufreq_frequency_table_get_attr(&centaur->freq_table[0], policy->cpu);
300         return 0;
301 }
302
303 static int eps_cpu_exit(struct cpufreq_policy *policy)
304 {
305         unsigned int cpu = policy->cpu;
306         struct eps_cpu_data *centaur;
307         u32 lo, hi;
308
309         if (eps_cpu[cpu] == NULL)
310                 return -ENODEV;
311         centaur = eps_cpu[cpu];
312
313         /* Get max frequency */
314         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
315         /* Set max frequency */
316         eps_set_state(centaur, cpu, hi & 0xffff);
317         /* Bye */
318         cpufreq_frequency_table_put_attr(policy->cpu);
319         kfree(eps_cpu[cpu]);
320         eps_cpu[cpu] = NULL;
321         return 0;
322 }
323
324 static struct freq_attr *eps_attr[] = {
325         &cpufreq_freq_attr_scaling_available_freqs,
326         NULL,
327 };
328
329 static struct cpufreq_driver eps_driver = {
330         .verify         = eps_verify,
331         .target         = eps_target,
332         .init           = eps_cpu_init,
333         .exit           = eps_cpu_exit,
334         .get            = eps_get,
335         .name           = "e_powersaver",
336         .owner          = THIS_MODULE,
337         .attr           = eps_attr,
338 };
339
340 static int __init eps_init(void)
341 {
342         struct cpuinfo_x86 *c = &cpu_data(0);
343
344         /* This driver will work only on Centaur C7 processors with
345          * Enhanced SpeedStep/PowerSaver registers */
346         if (c->x86_vendor != X86_VENDOR_CENTAUR
347             || c->x86 != 6 || c->x86_model < 10)
348                 return -ENODEV;
349         if (!cpu_has(c, X86_FEATURE_EST))
350                 return -ENODEV;
351
352         if (cpufreq_register_driver(&eps_driver))
353                 return -EINVAL;
354         return 0;
355 }
356
357 static void __exit eps_exit(void)
358 {
359         cpufreq_unregister_driver(&eps_driver);
360 }
361
362 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
363 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
364 MODULE_LICENSE("GPL");
365
366 module_init(eps_init);
367 module_exit(eps_exit);