2 * acpi-cpufreq-io.c - ACPI Processor P-States Driver ($Revision: 1.3 $)
4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6 * Copyright (C) 2002 - 2004 Dominik Brodowski <linux@brodo.de>
8 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or (at
13 * your option) any later version.
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
20 * You should have received a copy of the GNU General Public License along
21 * with this program; if not, write to the Free Software Foundation, Inc.,
22 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
24 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
27 #include <linux/config.h>
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/init.h>
31 #include <linux/cpufreq.h>
32 #include <linux/proc_fs.h>
33 #include <linux/seq_file.h>
35 #include <asm/delay.h>
36 #include <asm/uaccess.h>
38 #include <linux/acpi.h>
39 #include <acpi/processor.h>
41 #define ACPI_PROCESSOR_COMPONENT 0x01000000
42 #define ACPI_PROCESSOR_CLASS "processor"
43 #define ACPI_PROCESSOR_DRIVER_NAME "ACPI Processor P-States Driver"
44 #define ACPI_PROCESSOR_DEVICE_NAME "Processor"
46 #define _COMPONENT ACPI_PROCESSOR_COMPONENT
47 ACPI_MODULE_NAME ("acpi_processor_perf")
49 MODULE_AUTHOR("Paul Diefenbaugh, Dominik Brodowski");
50 MODULE_DESCRIPTION(ACPI_PROCESSOR_DRIVER_NAME);
51 MODULE_LICENSE("GPL");
54 struct cpufreq_acpi_io {
55 struct acpi_processor_performance acpi_data;
56 struct cpufreq_frequency_table *freq_table;
59 static struct cpufreq_acpi_io *acpi_io_data[NR_CPUS];
63 acpi_processor_write_port(
70 } else if (bit_width <= 16) {
72 } else if (bit_width <= 32) {
81 acpi_processor_read_port(
89 } else if (bit_width <= 16) {
91 } else if (bit_width <= 32) {
100 acpi_processor_set_performance (
101 struct cpufreq_acpi_io *data,
110 struct cpufreq_freqs cpufreq_freqs;
111 cpumask_t saved_mask;
114 ACPI_FUNCTION_TRACE("acpi_processor_set_performance");
117 * TBD: Use something other than set_cpus_allowed.
118 * As set_cpus_allowed is a bit racy,
119 * with any other set_cpus_allowed for this process.
121 saved_mask = current->cpus_allowed;
122 set_cpus_allowed(current, cpumask_of_cpu(cpu));
123 if (smp_processor_id() != cpu) {
124 return_VALUE(-EAGAIN);
127 if (state == data->acpi_data.state) {
128 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
129 "Already at target state (P%d)\n", state));
134 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Transitioning from P%d to P%d\n",
135 data->acpi_data.state, state));
137 /* cpufreq frequency struct */
138 cpufreq_freqs.cpu = cpu;
139 cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
140 cpufreq_freqs.new = data->freq_table[state].frequency;
143 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
146 * First we write the target state's 'control' value to the
150 port = data->acpi_data.control_register.address;
151 bit_width = data->acpi_data.control_register.bit_width;
152 value = (u32) data->acpi_data.states[state].control;
154 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
155 "Writing 0x%08x to port 0x%04x\n", value, port));
157 ret = acpi_processor_write_port(port, bit_width, value);
159 ACPI_DEBUG_PRINT((ACPI_DB_WARN,
160 "Invalid port width 0x%04x\n", bit_width));
166 * Then we read the 'status_register' and compare the value with the
167 * target state's 'status' to make sure the transition was successful.
168 * Note that we'll poll for up to 1ms (100 cycles of 10us) before
172 port = data->acpi_data.status_register.address;
173 bit_width = data->acpi_data.status_register.bit_width;
175 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
176 "Looking for 0x%08x from port 0x%04x\n",
177 (u32) data->acpi_data.states[state].status, port));
179 for (i=0; i<100; i++) {
180 ret = acpi_processor_read_port(port, bit_width, &value);
182 ACPI_DEBUG_PRINT((ACPI_DB_WARN,
183 "Invalid port width 0x%04x\n", bit_width));
187 if (value == (u32) data->acpi_data.states[state].status)
193 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
195 if (value != (u32) data->acpi_data.states[state].status) {
196 unsigned int tmp = cpufreq_freqs.new;
197 cpufreq_freqs.new = cpufreq_freqs.old;
198 cpufreq_freqs.old = tmp;
199 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
200 cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
201 ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Transition failed\n"));
206 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
207 "Transition successful after %d microseconds\n",
210 data->acpi_data.state = state;
214 set_cpus_allowed(current, saved_mask);
215 return_VALUE(retval);
220 acpi_cpufreq_target (
221 struct cpufreq_policy *policy,
222 unsigned int target_freq,
223 unsigned int relation)
225 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
226 unsigned int next_state = 0;
227 unsigned int result = 0;
229 ACPI_FUNCTION_TRACE("acpi_cpufreq_setpolicy");
231 result = cpufreq_frequency_table_target(policy,
237 return_VALUE(result);
239 result = acpi_processor_set_performance (data, policy->cpu, next_state);
241 return_VALUE(result);
246 acpi_cpufreq_verify (
247 struct cpufreq_policy *policy)
249 unsigned int result = 0;
250 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
252 ACPI_FUNCTION_TRACE("acpi_cpufreq_verify");
254 result = cpufreq_frequency_table_verify(policy,
257 return_VALUE(result);
262 acpi_cpufreq_guess_freq (
263 struct cpufreq_acpi_io *data,
267 /* search the closest match to cpu_khz */
270 unsigned long freqn = data->acpi_data.states[0].core_frequency * 1000;
272 for (i=0; i < (data->acpi_data.state_count - 1); i++) {
274 freqn = data->acpi_data.states[i+1].core_frequency * 1000;
275 if ((2 * cpu_khz) > (freqn + freq)) {
276 data->acpi_data.state = i;
280 data->acpi_data.state = data->acpi_data.state_count - 1;
283 /* assume CPU is at P0... */
284 data->acpi_data.state = 0;
285 return data->acpi_data.states[0].core_frequency * 1000;
291 * acpi_processor_cpu_init_pdc_est - let BIOS know about the SMP capabilities
293 * @perf: processor-specific acpi_io_data struct
294 * @cpu: CPU being initialized
296 * To avoid issues with legacy OSes, some BIOSes require to be informed of
297 * the SMP capabilities of OS P-state driver. Here we set the bits in _PDC
298 * accordingly, for Enhanced Speedstep. Actual call to _PDC is done in
299 * driver/acpi/processor.c
302 acpi_processor_cpu_init_pdc_est(
303 struct acpi_processor_performance *perf,
305 struct acpi_object_list *obj_list
308 union acpi_object *obj;
310 struct cpuinfo_x86 *c = cpu_data + cpu;
311 ACPI_FUNCTION_TRACE("acpi_processor_cpu_init_pdc_est");
313 if (!cpu_has(c, X86_FEATURE_EST))
316 /* Initialize pdc. It will be used later. */
320 if (!(obj_list->count && obj_list->pointer))
323 obj = obj_list->pointer;
324 if ((obj->buffer.length == 12) && obj->buffer.pointer) {
325 buf = (u32 *)obj->buffer.pointer;
326 buf[0] = ACPI_PDC_REVISION_ID;
328 buf[2] = ACPI_PDC_EST_CAPABILITY_SMP;
329 perf->pdc = obj_list;
335 /* CPU specific PDC initialization */
337 acpi_processor_cpu_init_pdc(
338 struct acpi_processor_performance *perf,
340 struct acpi_object_list *obj_list
343 struct cpuinfo_x86 *c = cpu_data + cpu;
344 ACPI_FUNCTION_TRACE("acpi_processor_cpu_init_pdc");
346 if (cpu_has(c, X86_FEATURE_EST))
347 acpi_processor_cpu_init_pdc_est(perf, cpu, obj_list);
353 acpi_cpufreq_cpu_init (
354 struct cpufreq_policy *policy)
357 unsigned int cpu = policy->cpu;
358 struct cpufreq_acpi_io *data;
359 unsigned int result = 0;
361 union acpi_object arg0 = {ACPI_TYPE_BUFFER};
363 struct acpi_object_list arg_list = {1, &arg0};
365 ACPI_FUNCTION_TRACE("acpi_cpufreq_cpu_init");
366 /* setup arg_list for _PDC settings */
367 arg0.buffer.length = 12;
368 arg0.buffer.pointer = (u8 *) arg0_buf;
370 data = kmalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
372 return_VALUE(-ENOMEM);
373 memset(data, 0, sizeof(struct cpufreq_acpi_io));
375 acpi_io_data[cpu] = data;
377 acpi_processor_cpu_init_pdc(&data->acpi_data, cpu, &arg_list);
378 result = acpi_processor_register_performance(&data->acpi_data, cpu);
379 data->acpi_data.pdc = NULL;
384 /* capability check */
385 if (data->acpi_data.state_count <= 1) {
386 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "No P-States\n"));
390 if ((data->acpi_data.control_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO) ||
391 (data->acpi_data.status_register.space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
392 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unsupported address space [%d, %d]\n",
393 (u32) (data->acpi_data.control_register.space_id),
394 (u32) (data->acpi_data.status_register.space_id)));
399 /* alloc freq_table */
400 data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) * (data->acpi_data.state_count + 1), GFP_KERNEL);
401 if (!data->freq_table) {
406 /* detect transition latency */
407 policy->cpuinfo.transition_latency = 0;
408 for (i=0; i<data->acpi_data.state_count; i++) {
409 if ((data->acpi_data.states[i].transition_latency * 1000) > policy->cpuinfo.transition_latency)
410 policy->cpuinfo.transition_latency = data->acpi_data.states[i].transition_latency * 1000;
412 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
414 /* The current speed is unknown and not detectable by ACPI... */
415 policy->cur = acpi_cpufreq_guess_freq(data, policy->cpu);
418 for (i=0; i<=data->acpi_data.state_count; i++)
420 data->freq_table[i].index = i;
421 if (i<data->acpi_data.state_count)
422 data->freq_table[i].frequency = data->acpi_data.states[i].core_frequency * 1000;
424 data->freq_table[i].frequency = CPUFREQ_TABLE_END;
427 result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
433 printk(KERN_INFO "cpufreq: CPU%u - ACPI performance management activated.\n",
435 for (i = 0; i < data->acpi_data.state_count; i++)
436 printk(KERN_INFO "cpufreq: %cP%d: %d MHz, %d mW, %d uS\n",
437 (i == data->acpi_data.state?'*':' '), i,
438 (u32) data->acpi_data.states[i].core_frequency,
439 (u32) data->acpi_data.states[i].power,
440 (u32) data->acpi_data.states[i].transition_latency);
442 cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
443 return_VALUE(result);
446 kfree(data->freq_table);
448 acpi_processor_unregister_performance(&data->acpi_data, cpu);
451 acpi_io_data[cpu] = NULL;
453 return_VALUE(result);
458 acpi_cpufreq_cpu_exit (
459 struct cpufreq_policy *policy)
461 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
464 ACPI_FUNCTION_TRACE("acpi_cpufreq_cpu_exit");
467 cpufreq_frequency_table_put_attr(policy->cpu);
468 acpi_io_data[policy->cpu] = NULL;
469 acpi_processor_unregister_performance(&data->acpi_data, policy->cpu);
477 static struct freq_attr* acpi_cpufreq_attr[] = {
478 &cpufreq_freq_attr_scaling_available_freqs,
482 static struct cpufreq_driver acpi_cpufreq_driver = {
483 .verify = acpi_cpufreq_verify,
484 .target = acpi_cpufreq_target,
485 .init = acpi_cpufreq_cpu_init,
486 .exit = acpi_cpufreq_cpu_exit,
487 .name = "acpi-cpufreq",
488 .owner = THIS_MODULE,
489 .attr = acpi_cpufreq_attr,
494 acpi_cpufreq_init (void)
498 ACPI_FUNCTION_TRACE("acpi_cpufreq_init");
500 result = cpufreq_register_driver(&acpi_cpufreq_driver);
502 return_VALUE(result);
507 acpi_cpufreq_exit (void)
509 ACPI_FUNCTION_TRACE("acpi_cpufreq_exit");
511 cpufreq_unregister_driver(&acpi_cpufreq_driver);
517 late_initcall(acpi_cpufreq_init);
518 module_exit(acpi_cpufreq_exit);