1 /*
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)
6 *
7 * Copyright (C) 2005 Intel Corp
8 * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
9 */
10
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
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>
20 #include <asm/io.h>
21 #include <asm/uaccess.h>
22 #include <asm/pal.h>
23
24 #include <linux/acpi.h>
25 #include <acpi/processor.h>
26
27 MODULE_AUTHOR("Venkatesh Pallipadi");
28 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
29 MODULE_LICENSE("GPL");
30
31
32 struct cpufreq_acpi_io {
33 struct acpi_processor_performance acpi_data;
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 pr_warn("get performance failed with error %d\n", ret);
124 ret = 0;
125 goto migrate_end;
126 }
127 clock_freq = extract_clock(data, value, cpu);
128 ret = (clock_freq*1000);
129
130 migrate_end:
131 set_cpus_allowed_ptr(current, &saved_mask);
132 return ret;
133 }
134
135
136 static int
processor_set_freq(struct cpufreq_acpi_io * data,struct cpufreq_policy * policy,int state)137 processor_set_freq (
138 struct cpufreq_acpi_io *data,
139 struct cpufreq_policy *policy,
140 int state)
141 {
142 int ret = 0;
143 u32 value = 0;
144 cpumask_t saved_mask;
145 int retval;
146
147 pr_debug("processor_set_freq\n");
148
149 saved_mask = current->cpus_allowed;
150 set_cpus_allowed_ptr(current, cpumask_of(policy->cpu));
151 if (smp_processor_id() != policy->cpu) {
152 retval = -EAGAIN;
153 goto migrate_end;
154 }
155
156 if (state == data->acpi_data.state) {
157 if (unlikely(data->resume)) {
158 pr_debug("Called after resume, resetting to P%d\n", state);
159 data->resume = 0;
160 } else {
161 pr_debug("Already at target state (P%d)\n", state);
162 retval = 0;
163 goto migrate_end;
164 }
165 }
166
167 pr_debug("Transitioning from P%d to P%d\n",
168 data->acpi_data.state, state);
169
170 /*
171 * First we write the target state's 'control' value to the
172 * control_register.
173 */
174
175 value = (u32) data->acpi_data.states[state].control;
176
177 pr_debug("Transitioning to state: 0x%08x\n", value);
178
179 ret = processor_set_pstate(value);
180 if (ret) {
181 pr_warn("Transition failed with error %d\n", ret);
182 retval = -ENODEV;
183 goto migrate_end;
184 }
185
186 data->acpi_data.state = state;
187
188 retval = 0;
189
190 migrate_end:
191 set_cpus_allowed_ptr(current, &saved_mask);
192 return (retval);
193 }
194
195
196 static unsigned int
acpi_cpufreq_get(unsigned int cpu)197 acpi_cpufreq_get (
198 unsigned int cpu)
199 {
200 struct cpufreq_acpi_io *data = acpi_io_data[cpu];
201
202 pr_debug("acpi_cpufreq_get\n");
203
204 return processor_get_freq(data, cpu);
205 }
206
207
208 static int
acpi_cpufreq_target(struct cpufreq_policy * policy,unsigned int index)209 acpi_cpufreq_target (
210 struct cpufreq_policy *policy,
211 unsigned int index)
212 {
213 return processor_set_freq(acpi_io_data[policy->cpu], policy, index);
214 }
215
216 static int
acpi_cpufreq_cpu_init(struct cpufreq_policy * policy)217 acpi_cpufreq_cpu_init (
218 struct cpufreq_policy *policy)
219 {
220 unsigned int i;
221 unsigned int cpu = policy->cpu;
222 struct cpufreq_acpi_io *data;
223 unsigned int result = 0;
224 struct cpufreq_frequency_table *freq_table;
225
226 pr_debug("acpi_cpufreq_cpu_init\n");
227
228 data = kzalloc(sizeof(*data), GFP_KERNEL);
229 if (!data)
230 return (-ENOMEM);
231
232 acpi_io_data[cpu] = data;
233
234 result = acpi_processor_register_performance(&data->acpi_data, cpu);
235
236 if (result)
237 goto err_free;
238
239 /* capability check */
240 if (data->acpi_data.state_count <= 1) {
241 pr_debug("No P-States\n");
242 result = -ENODEV;
243 goto err_unreg;
244 }
245
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));
253 result = -ENODEV;
254 goto err_unreg;
255 }
256
257 /* alloc freq_table */
258 freq_table = kzalloc(sizeof(*freq_table) *
259 (data->acpi_data.state_count + 1),
260 GFP_KERNEL);
261 if (!freq_table) {
262 result = -ENOMEM;
263 goto err_unreg;
264 }
265
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;
273 }
274 }
275
276 /* table init */
277 for (i = 0; i <= data->acpi_data.state_count; i++)
278 {
279 if (i < data->acpi_data.state_count) {
280 freq_table[i].frequency =
281 data->acpi_data.states[i].core_frequency * 1000;
282 } else {
283 freq_table[i].frequency = CPUFREQ_TABLE_END;
284 }
285 }
286
287 result = cpufreq_table_validate_and_show(policy, freq_table);
288 if (result) {
289 goto err_freqfree;
290 }
291
292 /* notify BIOS that we exist */
293 acpi_processor_notify_smm(THIS_MODULE);
294
295 pr_info("CPU%u - ACPI performance management activated\n", cpu);
296
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);
306
307 /* the first call to ->target() should result in us actually
308 * writing something to the appropriate registers. */
309 data->resume = 1;
310
311 return (result);
312
313 err_freqfree:
314 kfree(freq_table);
315 err_unreg:
316 acpi_processor_unregister_performance(cpu);
317 err_free:
318 kfree(data);
319 acpi_io_data[cpu] = NULL;
320
321 return (result);
322 }
323
324
325 static int
acpi_cpufreq_cpu_exit(struct cpufreq_policy * policy)326 acpi_cpufreq_cpu_exit (
327 struct cpufreq_policy *policy)
328 {
329 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
330
331 pr_debug("acpi_cpufreq_cpu_exit\n");
332
333 if (data) {
334 acpi_io_data[policy->cpu] = NULL;
335 acpi_processor_unregister_performance(policy->cpu);
336 kfree(policy->freq_table);
337 kfree(data);
338 }
339
340 return (0);
341 }
342
343
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,
352 };
353
354
355 static int __init
acpi_cpufreq_init(void)356 acpi_cpufreq_init (void)
357 {
358 pr_debug("acpi_cpufreq_init\n");
359
360 return cpufreq_register_driver(&acpi_cpufreq_driver);
361 }
362
363
364 static void __exit
acpi_cpufreq_exit(void)365 acpi_cpufreq_exit (void)
366 {
367 pr_debug("acpi_cpufreq_exit\n");
368
369 cpufreq_unregister_driver(&acpi_cpufreq_driver);
370 return;
371 }
372
373
374 late_initcall(acpi_cpufreq_init);
375 module_exit(acpi_cpufreq_exit);
376
377