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