2 * This file provides the ACPI based P-state support. This
3 * module works with generic cpufreq infrastructure. Most of
4 * the code is based on i386 version
5 * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)
7 * Copyright (C) 2005 Intel Corp
8 * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/cpufreq.h>
18 #include <linux/proc_fs.h>
19 #include <linux/seq_file.h>
21 #include <asm/uaccess.h>
24 #include <linux/acpi.h>
25 #include <acpi/processor.h>
27 MODULE_AUTHOR("Venkatesh Pallipadi");
28 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
29 MODULE_LICENSE("GPL");
32 struct cpufreq_acpi_io {
33 struct acpi_processor_performance acpi_data;
37 static struct cpufreq_acpi_io *acpi_io_data[NR_CPUS];
39 static struct cpufreq_driver acpi_cpufreq_driver;
43 processor_set_pstate (
48 pr_debug("processor_set_pstate\n");
50 retval = ia64_pal_set_pstate((u64)value);
53 pr_debug("Failed to set freq to 0x%x, with error 0x%lx\n",
62 processor_get_pstate (
68 pr_debug("processor_get_pstate\n");
70 retval = ia64_pal_get_pstate(&pstate_index,
71 PAL_GET_PSTATE_TYPE_INSTANT);
72 *value = (u32) pstate_index;
75 pr_debug("Failed to get current freq with "
76 "error 0x%lx, idx 0x%x\n", retval, *value);
82 /* To be used only after data->acpi_data is initialized */
85 struct cpufreq_acpi_io *data,
91 pr_debug("extract_clock\n");
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;
97 return data->acpi_data.states[i-1].core_frequency;
103 struct cpufreq_acpi_io *data,
108 cpumask_t saved_mask;
109 unsigned long clock_freq;
111 pr_debug("processor_get_freq\n");
113 saved_mask = current->cpus_allowed;
114 set_cpus_allowed_ptr(current, cpumask_of(cpu));
115 if (smp_processor_id() != cpu)
118 /* processor_get_pstate gets the instantaneous frequency */
119 ret = processor_get_pstate(&value);
122 set_cpus_allowed_ptr(current, &saved_mask);
123 pr_warn("get performance failed with error %d\n", ret);
127 clock_freq = extract_clock(data, value, cpu);
128 ret = (clock_freq*1000);
131 set_cpus_allowed_ptr(current, &saved_mask);
138 struct cpufreq_acpi_io *data,
139 struct cpufreq_policy *policy,
144 cpumask_t saved_mask;
147 pr_debug("processor_set_freq\n");
149 saved_mask = current->cpus_allowed;
150 set_cpus_allowed_ptr(current, cpumask_of(policy->cpu));
151 if (smp_processor_id() != policy->cpu) {
156 if (state == data->acpi_data.state) {
157 if (unlikely(data->resume)) {
158 pr_debug("Called after resume, resetting to P%d\n", state);
161 pr_debug("Already at target state (P%d)\n", state);
167 pr_debug("Transitioning from P%d to P%d\n",
168 data->acpi_data.state, state);
171 * First we write the target state's 'control' value to the
175 value = (u32) data->acpi_data.states[state].control;
177 pr_debug("Transitioning to state: 0x%08x\n", value);
179 ret = processor_set_pstate(value);
181 pr_warn("Transition failed with error %d\n", ret);
186 data->acpi_data.state = state;
191 set_cpus_allowed_ptr(current, &saved_mask);
200 struct cpufreq_acpi_io *data = acpi_io_data[cpu];
202 pr_debug("acpi_cpufreq_get\n");
204 return processor_get_freq(data, cpu);
209 acpi_cpufreq_target (
210 struct cpufreq_policy *policy,
213 return processor_set_freq(acpi_io_data[policy->cpu], policy, index);
217 acpi_cpufreq_cpu_init (
218 struct cpufreq_policy *policy)
221 unsigned int cpu = policy->cpu;
222 struct cpufreq_acpi_io *data;
223 unsigned int result = 0;
224 struct cpufreq_frequency_table *freq_table;
226 pr_debug("acpi_cpufreq_cpu_init\n");
228 data = kzalloc(sizeof(*data), GFP_KERNEL);
232 acpi_io_data[cpu] = data;
234 result = acpi_processor_register_performance(&data->acpi_data, cpu);
239 /* capability check */
240 if (data->acpi_data.state_count <= 1) {
241 pr_debug("No P-States\n");
246 if ((data->acpi_data.control_register.space_id !=
247 ACPI_ADR_SPACE_FIXED_HARDWARE) ||
248 (data->acpi_data.status_register.space_id !=
249 ACPI_ADR_SPACE_FIXED_HARDWARE)) {
250 pr_debug("Unsupported address space [%d, %d]\n",
251 (u32) (data->acpi_data.control_register.space_id),
252 (u32) (data->acpi_data.status_register.space_id));
257 /* alloc freq_table */
258 freq_table = kzalloc(sizeof(*freq_table) *
259 (data->acpi_data.state_count + 1),
266 /* detect transition latency */
267 policy->cpuinfo.transition_latency = 0;
268 for (i=0; i<data->acpi_data.state_count; i++) {
269 if ((data->acpi_data.states[i].transition_latency * 1000) >
270 policy->cpuinfo.transition_latency) {
271 policy->cpuinfo.transition_latency =
272 data->acpi_data.states[i].transition_latency * 1000;
277 for (i = 0; i <= data->acpi_data.state_count; i++)
279 if (i < data->acpi_data.state_count) {
280 freq_table[i].frequency =
281 data->acpi_data.states[i].core_frequency * 1000;
283 freq_table[i].frequency = CPUFREQ_TABLE_END;
287 result = cpufreq_table_validate_and_show(policy, freq_table);
292 /* notify BIOS that we exist */
293 acpi_processor_notify_smm(THIS_MODULE);
295 pr_info("CPU%u - ACPI performance management activated\n", cpu);
297 for (i = 0; i < data->acpi_data.state_count; i++)
298 pr_debug(" %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
299 (i == data->acpi_data.state?'*':' '), i,
300 (u32) data->acpi_data.states[i].core_frequency,
301 (u32) data->acpi_data.states[i].power,
302 (u32) data->acpi_data.states[i].transition_latency,
303 (u32) data->acpi_data.states[i].bus_master_latency,
304 (u32) data->acpi_data.states[i].status,
305 (u32) data->acpi_data.states[i].control);
307 /* the first call to ->target() should result in us actually
308 * writing something to the appropriate registers. */
316 acpi_processor_unregister_performance(cpu);
319 acpi_io_data[cpu] = NULL;
326 acpi_cpufreq_cpu_exit (
327 struct cpufreq_policy *policy)
329 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
331 pr_debug("acpi_cpufreq_cpu_exit\n");
334 acpi_io_data[policy->cpu] = NULL;
335 acpi_processor_unregister_performance(policy->cpu);
336 kfree(policy->freq_table);
344 static struct cpufreq_driver acpi_cpufreq_driver = {
345 .verify = cpufreq_generic_frequency_table_verify,
346 .target_index = acpi_cpufreq_target,
347 .get = acpi_cpufreq_get,
348 .init = acpi_cpufreq_cpu_init,
349 .exit = acpi_cpufreq_cpu_exit,
350 .name = "acpi-cpufreq",
351 .attr = cpufreq_generic_attr,
356 acpi_cpufreq_init (void)
358 pr_debug("acpi_cpufreq_init\n");
360 return cpufreq_register_driver(&acpi_cpufreq_driver);
365 acpi_cpufreq_exit (void)
367 pr_debug("acpi_cpufreq_exit\n");
369 cpufreq_unregister_driver(&acpi_cpufreq_driver);
374 late_initcall(acpi_cpufreq_init);
375 module_exit(acpi_cpufreq_exit);