1 /*
2 * arch/ia64/kernel/cpufreq/acpi-cpufreq.c
3 * This file provides the ACPI based P-state support. This
4 * module works with generic cpufreq infrastructure. Most of
5 * the code is based on i386 version
6 * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)
7 *
8 * Copyright (C) 2005 Intel Corp
9 * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/cpufreq.h>
17 #include <linux/proc_fs.h>
18 #include <linux/seq_file.h>
19 #include <asm/io.h>
20 #include <asm/uaccess.h>
21 #include <asm/pal.h>
22
23 #include <linux/acpi.h>
24 #include <acpi/processor.h>
25
26 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
27
28 MODULE_AUTHOR("Venkatesh Pallipadi");
29 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
30 MODULE_LICENSE("GPL");
31
32
33 struct cpufreq_acpi_io {
34 struct acpi_processor_performance acpi_data;
35 struct cpufreq_frequency_table *freq_table;
36 unsigned int resume;
37 };
38
39 static struct cpufreq_acpi_io *acpi_io_data[NR_CPUS];
40
41 static struct cpufreq_driver acpi_cpufreq_driver;
42
43
44 static int
processor_set_pstate(u32 value)45 processor_set_pstate (
46 u32 value)
47 {
48 s64 retval;
49
50 dprintk("processor_set_pstate\n");
51
52 retval = ia64_pal_set_pstate((u64)value);
53
54 if (retval) {
55 dprintk("Failed to set freq to 0x%x, with error 0x%lx\n",
56 value, retval);
57 return -ENODEV;
58 }
59 return (int)retval;
60 }
61
62
63 static int
processor_get_pstate(u32 * value)64 processor_get_pstate (
65 u32 *value)
66 {
67 u64 pstate_index = 0;
68 s64 retval;
69
70 dprintk("processor_get_pstate\n");
71
72 retval = ia64_pal_get_pstate(&pstate_index,
73 PAL_GET_PSTATE_TYPE_INSTANT);
74 *value = (u32) pstate_index;
75
76 if (retval)
77 dprintk("Failed to get current freq with "
78 "error 0x%lx, idx 0x%x\n", retval, *value);
79
80 return (int)retval;
81 }
82
83
84 /* To be used only after data->acpi_data is initialized */
85 static unsigned
extract_clock(struct cpufreq_acpi_io * data,unsigned value,unsigned int cpu)86 extract_clock (
87 struct cpufreq_acpi_io *data,
88 unsigned value,
89 unsigned int cpu)
90 {
91 unsigned long i;
92
93 dprintk("extract_clock\n");
94
95 for (i = 0; i < data->acpi_data.state_count; i++) {
96 if (value == data->acpi_data.states[i].status)
97 return data->acpi_data.states[i].core_frequency;
98 }
99 return data->acpi_data.states[i-1].core_frequency;
100 }
101
102
103 static unsigned int
processor_get_freq(struct cpufreq_acpi_io * data,unsigned int cpu)104 processor_get_freq (
105 struct cpufreq_acpi_io *data,
106 unsigned int cpu)
107 {
108 int ret = 0;
109 u32 value = 0;
110 cpumask_t saved_mask;
111 unsigned long clock_freq;
112
113 dprintk("processor_get_freq\n");
114
115 saved_mask = current->cpus_allowed;
116 set_cpus_allowed_ptr(current, cpumask_of(cpu));
117 if (smp_processor_id() != cpu)
118 goto migrate_end;
119
120 /* processor_get_pstate gets the instantaneous frequency */
121 ret = processor_get_pstate(&value);
122
123 if (ret) {
124 set_cpus_allowed_ptr(current, &saved_mask);
125 printk(KERN_WARNING "get performance failed with error %d\n",
126 ret);
127 ret = 0;
128 goto migrate_end;
129 }
130 clock_freq = extract_clock(data, value, cpu);
131 ret = (clock_freq*1000);
132
133 migrate_end:
134 set_cpus_allowed_ptr(current, &saved_mask);
135 return ret;
136 }
137
138
139 static int
processor_set_freq(struct cpufreq_acpi_io * data,unsigned int cpu,int state)140 processor_set_freq (
141 struct cpufreq_acpi_io *data,
142 unsigned int cpu,
143 int state)
144 {
145 int ret = 0;
146 u32 value = 0;
147 struct cpufreq_freqs cpufreq_freqs;
148 cpumask_t saved_mask;
149 int retval;
150
151 dprintk("processor_set_freq\n");
152
153 saved_mask = current->cpus_allowed;
154 set_cpus_allowed_ptr(current, cpumask_of(cpu));
155 if (smp_processor_id() != cpu) {
156 retval = -EAGAIN;
157 goto migrate_end;
158 }
159
160 if (state == data->acpi_data.state) {
161 if (unlikely(data->resume)) {
162 dprintk("Called after resume, resetting to P%d\n", state);
163 data->resume = 0;
164 } else {
165 dprintk("Already at target state (P%d)\n", state);
166 retval = 0;
167 goto migrate_end;
168 }
169 }
170
171 dprintk("Transitioning from P%d to P%d\n",
172 data->acpi_data.state, state);
173
174 /* cpufreq frequency struct */
175 cpufreq_freqs.cpu = cpu;
176 cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
177 cpufreq_freqs.new = data->freq_table[state].frequency;
178
179 /* notify cpufreq */
180 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
181
182 /*
183 * First we write the target state's 'control' value to the
184 * control_register.
185 */
186
187 value = (u32) data->acpi_data.states[state].control;
188
189 dprintk("Transitioning to state: 0x%08x\n", value);
190
191 ret = processor_set_pstate(value);
192 if (ret) {
193 unsigned int tmp = cpufreq_freqs.new;
194 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
195 cpufreq_freqs.new = cpufreq_freqs.old;
196 cpufreq_freqs.old = tmp;
197 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
198 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
199 printk(KERN_WARNING "Transition failed with error %d\n", ret);
200 retval = -ENODEV;
201 goto migrate_end;
202 }
203
204 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
205
206 data->acpi_data.state = state;
207
208 retval = 0;
209
210 migrate_end:
211 set_cpus_allowed_ptr(current, &saved_mask);
212 return (retval);
213 }
214
215
216 static unsigned int
acpi_cpufreq_get(unsigned int cpu)217 acpi_cpufreq_get (
218 unsigned int cpu)
219 {
220 struct cpufreq_acpi_io *data = acpi_io_data[cpu];
221
222 dprintk("acpi_cpufreq_get\n");
223
224 return processor_get_freq(data, cpu);
225 }
226
227
228 static int
acpi_cpufreq_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)229 acpi_cpufreq_target (
230 struct cpufreq_policy *policy,
231 unsigned int target_freq,
232 unsigned int relation)
233 {
234 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
235 unsigned int next_state = 0;
236 unsigned int result = 0;
237
238 dprintk("acpi_cpufreq_setpolicy\n");
239
240 result = cpufreq_frequency_table_target(policy,
241 data->freq_table, target_freq, relation, &next_state);
242 if (result)
243 return (result);
244
245 result = processor_set_freq(data, policy->cpu, next_state);
246
247 return (result);
248 }
249
250
251 static int
acpi_cpufreq_verify(struct cpufreq_policy * policy)252 acpi_cpufreq_verify (
253 struct cpufreq_policy *policy)
254 {
255 unsigned int result = 0;
256 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
257
258 dprintk("acpi_cpufreq_verify\n");
259
260 result = cpufreq_frequency_table_verify(policy,
261 data->freq_table);
262
263 return (result);
264 }
265
266
267 static int
acpi_cpufreq_cpu_init(struct cpufreq_policy * policy)268 acpi_cpufreq_cpu_init (
269 struct cpufreq_policy *policy)
270 {
271 unsigned int i;
272 unsigned int cpu = policy->cpu;
273 struct cpufreq_acpi_io *data;
274 unsigned int result = 0;
275
276 dprintk("acpi_cpufreq_cpu_init\n");
277
278 data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
279 if (!data)
280 return (-ENOMEM);
281
282 acpi_io_data[cpu] = data;
283
284 result = acpi_processor_register_performance(&data->acpi_data, cpu);
285
286 if (result)
287 goto err_free;
288
289 /* capability check */
290 if (data->acpi_data.state_count <= 1) {
291 dprintk("No P-States\n");
292 result = -ENODEV;
293 goto err_unreg;
294 }
295
296 if ((data->acpi_data.control_register.space_id !=
297 ACPI_ADR_SPACE_FIXED_HARDWARE) ||
298 (data->acpi_data.status_register.space_id !=
299 ACPI_ADR_SPACE_FIXED_HARDWARE)) {
300 dprintk("Unsupported address space [%d, %d]\n",
301 (u32) (data->acpi_data.control_register.space_id),
302 (u32) (data->acpi_data.status_register.space_id));
303 result = -ENODEV;
304 goto err_unreg;
305 }
306
307 /* alloc freq_table */
308 data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
309 (data->acpi_data.state_count + 1),
310 GFP_KERNEL);
311 if (!data->freq_table) {
312 result = -ENOMEM;
313 goto err_unreg;
314 }
315
316 /* detect transition latency */
317 policy->cpuinfo.transition_latency = 0;
318 for (i=0; i<data->acpi_data.state_count; i++) {
319 if ((data->acpi_data.states[i].transition_latency * 1000) >
320 policy->cpuinfo.transition_latency) {
321 policy->cpuinfo.transition_latency =
322 data->acpi_data.states[i].transition_latency * 1000;
323 }
324 }
325 policy->cur = processor_get_freq(data, policy->cpu);
326
327 /* table init */
328 for (i = 0; i <= data->acpi_data.state_count; i++)
329 {
330 data->freq_table[i].index = i;
331 if (i < data->acpi_data.state_count) {
332 data->freq_table[i].frequency =
333 data->acpi_data.states[i].core_frequency * 1000;
334 } else {
335 data->freq_table[i].frequency = CPUFREQ_TABLE_END;
336 }
337 }
338
339 result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
340 if (result) {
341 goto err_freqfree;
342 }
343
344 /* notify BIOS that we exist */
345 acpi_processor_notify_smm(THIS_MODULE);
346
347 printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "
348 "activated.\n", cpu);
349
350 for (i = 0; i < data->acpi_data.state_count; i++)
351 dprintk(" %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
352 (i == data->acpi_data.state?'*':' '), i,
353 (u32) data->acpi_data.states[i].core_frequency,
354 (u32) data->acpi_data.states[i].power,
355 (u32) data->acpi_data.states[i].transition_latency,
356 (u32) data->acpi_data.states[i].bus_master_latency,
357 (u32) data->acpi_data.states[i].status,
358 (u32) data->acpi_data.states[i].control);
359
360 cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
361
362 /* the first call to ->target() should result in us actually
363 * writing something to the appropriate registers. */
364 data->resume = 1;
365
366 return (result);
367
368 err_freqfree:
369 kfree(data->freq_table);
370 err_unreg:
371 acpi_processor_unregister_performance(&data->acpi_data, cpu);
372 err_free:
373 kfree(data);
374 acpi_io_data[cpu] = NULL;
375
376 return (result);
377 }
378
379
380 static int
acpi_cpufreq_cpu_exit(struct cpufreq_policy * policy)381 acpi_cpufreq_cpu_exit (
382 struct cpufreq_policy *policy)
383 {
384 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
385
386 dprintk("acpi_cpufreq_cpu_exit\n");
387
388 if (data) {
389 cpufreq_frequency_table_put_attr(policy->cpu);
390 acpi_io_data[policy->cpu] = NULL;
391 acpi_processor_unregister_performance(&data->acpi_data,
392 policy->cpu);
393 kfree(data);
394 }
395
396 return (0);
397 }
398
399
400 static struct freq_attr* acpi_cpufreq_attr[] = {
401 &cpufreq_freq_attr_scaling_available_freqs,
402 NULL,
403 };
404
405
406 static struct cpufreq_driver acpi_cpufreq_driver = {
407 .verify = acpi_cpufreq_verify,
408 .target = acpi_cpufreq_target,
409 .get = acpi_cpufreq_get,
410 .init = acpi_cpufreq_cpu_init,
411 .exit = acpi_cpufreq_cpu_exit,
412 .name = "acpi-cpufreq",
413 .owner = THIS_MODULE,
414 .attr = acpi_cpufreq_attr,
415 };
416
417
418 static int __init
acpi_cpufreq_init(void)419 acpi_cpufreq_init (void)
420 {
421 dprintk("acpi_cpufreq_init\n");
422
423 return cpufreq_register_driver(&acpi_cpufreq_driver);
424 }
425
426
427 static void __exit
acpi_cpufreq_exit(void)428 acpi_cpufreq_exit (void)
429 {
430 dprintk("acpi_cpufreq_exit\n");
431
432 cpufreq_unregister_driver(&acpi_cpufreq_driver);
433 return;
434 }
435
436
437 late_initcall(acpi_cpufreq_init);
438 module_exit(acpi_cpufreq_exit);
439
440