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11#include <linux/kernel.h>
12#include <linux/slab.h>
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/cpufreq.h>
16#include <linux/proc_fs.h>
17#include <linux/seq_file.h>
18#include <asm/io.h>
19#include <asm/uaccess.h>
20#include <asm/pal.h>
21
22#include <linux/acpi.h>
23#include <acpi/processor.h>
24
25MODULE_AUTHOR("Venkatesh Pallipadi");
26MODULE_DESCRIPTION("ACPI Processor P-States Driver");
27MODULE_LICENSE("GPL");
28
29
30struct cpufreq_acpi_io {
31 struct acpi_processor_performance acpi_data;
32 struct cpufreq_frequency_table *freq_table;
33 unsigned int resume;
34};
35
36static struct cpufreq_acpi_io *acpi_io_data[NR_CPUS];
37
38static struct cpufreq_driver acpi_cpufreq_driver;
39
40
41static int
42processor_set_pstate (
43 u32 value)
44{
45 s64 retval;
46
47 pr_debug("processor_set_pstate\n");
48
49 retval = ia64_pal_set_pstate((u64)value);
50
51 if (retval) {
52 pr_debug("Failed to set freq to 0x%x, with error 0x%lx\n",
53 value, retval);
54 return -ENODEV;
55 }
56 return (int)retval;
57}
58
59
60static int
61processor_get_pstate (
62 u32 *value)
63{
64 u64 pstate_index = 0;
65 s64 retval;
66
67 pr_debug("processor_get_pstate\n");
68
69 retval = ia64_pal_get_pstate(&pstate_index,
70 PAL_GET_PSTATE_TYPE_INSTANT);
71 *value = (u32) pstate_index;
72
73 if (retval)
74 pr_debug("Failed to get current freq with "
75 "error 0x%lx, idx 0x%x\n", retval, *value);
76
77 return (int)retval;
78}
79
80
81
82static unsigned
83extract_clock (
84 struct cpufreq_acpi_io *data,
85 unsigned value,
86 unsigned int cpu)
87{
88 unsigned long i;
89
90 pr_debug("extract_clock\n");
91
92 for (i = 0; i < data->acpi_data.state_count; i++) {
93 if (value == data->acpi_data.states[i].status)
94 return data->acpi_data.states[i].core_frequency;
95 }
96 return data->acpi_data.states[i-1].core_frequency;
97}
98
99
100static unsigned int
101processor_get_freq (
102 struct cpufreq_acpi_io *data,
103 unsigned int cpu)
104{
105 int ret = 0;
106 u32 value = 0;
107 cpumask_t saved_mask;
108 unsigned long clock_freq;
109
110 pr_debug("processor_get_freq\n");
111
112 saved_mask = current->cpus_allowed;
113 set_cpus_allowed_ptr(current, cpumask_of(cpu));
114 if (smp_processor_id() != cpu)
115 goto migrate_end;
116
117
118 ret = processor_get_pstate(&value);
119
120 if (ret) {
121 set_cpus_allowed_ptr(current, &saved_mask);
122 printk(KERN_WARNING "get performance failed with error %d\n",
123 ret);
124 ret = 0;
125 goto migrate_end;
126 }
127 clock_freq = extract_clock(data, value, cpu);
128 ret = (clock_freq*1000);
129
130migrate_end:
131 set_cpus_allowed_ptr(current, &saved_mask);
132 return ret;
133}
134
135
136static int
137processor_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
172
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 printk(KERN_WARNING "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
190migrate_end:
191 set_cpus_allowed_ptr(current, &saved_mask);
192 return (retval);
193}
194
195
196static unsigned int
197acpi_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
208static int
209acpi_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
216static int
217acpi_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
225 pr_debug("acpi_cpufreq_cpu_init\n");
226
227 data = kzalloc(sizeof(*data), GFP_KERNEL);
228 if (!data)
229 return (-ENOMEM);
230
231 acpi_io_data[cpu] = data;
232
233 result = acpi_processor_register_performance(&data->acpi_data, cpu);
234
235 if (result)
236 goto err_free;
237
238
239 if (data->acpi_data.state_count <= 1) {
240 pr_debug("No P-States\n");
241 result = -ENODEV;
242 goto err_unreg;
243 }
244
245 if ((data->acpi_data.control_register.space_id !=
246 ACPI_ADR_SPACE_FIXED_HARDWARE) ||
247 (data->acpi_data.status_register.space_id !=
248 ACPI_ADR_SPACE_FIXED_HARDWARE)) {
249 pr_debug("Unsupported address space [%d, %d]\n",
250 (u32) (data->acpi_data.control_register.space_id),
251 (u32) (data->acpi_data.status_register.space_id));
252 result = -ENODEV;
253 goto err_unreg;
254 }
255
256
257 data->freq_table = kzalloc(sizeof(*data->freq_table) *
258 (data->acpi_data.state_count + 1),
259 GFP_KERNEL);
260 if (!data->freq_table) {
261 result = -ENOMEM;
262 goto err_unreg;
263 }
264
265
266 policy->cpuinfo.transition_latency = 0;
267 for (i=0; i<data->acpi_data.state_count; i++) {
268 if ((data->acpi_data.states[i].transition_latency * 1000) >
269 policy->cpuinfo.transition_latency) {
270 policy->cpuinfo.transition_latency =
271 data->acpi_data.states[i].transition_latency * 1000;
272 }
273 }
274
275
276 for (i = 0; i <= data->acpi_data.state_count; i++)
277 {
278 if (i < data->acpi_data.state_count) {
279 data->freq_table[i].frequency =
280 data->acpi_data.states[i].core_frequency * 1000;
281 } else {
282 data->freq_table[i].frequency = CPUFREQ_TABLE_END;
283 }
284 }
285
286 result = cpufreq_table_validate_and_show(policy, data->freq_table);
287 if (result) {
288 goto err_freqfree;
289 }
290
291
292 acpi_processor_notify_smm(THIS_MODULE);
293
294 printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "
295 "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
308
309 data->resume = 1;
310
311 return (result);
312
313 err_freqfree:
314 kfree(data->freq_table);
315 err_unreg:
316 acpi_processor_unregister_performance(&data->acpi_data, cpu);
317 err_free:
318 kfree(data);
319 acpi_io_data[cpu] = NULL;
320
321 return (result);
322}
323
324
325static int
326acpi_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(&data->acpi_data,
336 policy->cpu);
337 kfree(data);
338 }
339
340 return (0);
341}
342
343
344static 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
355static int __init
356acpi_cpufreq_init (void)
357{
358 pr_debug("acpi_cpufreq_init\n");
359
360 return cpufreq_register_driver(&acpi_cpufreq_driver);
361}
362
363
364static void __exit
365acpi_cpufreq_exit (void)
366{
367 pr_debug("acpi_cpufreq_exit\n");
368
369 cpufreq_unregister_driver(&acpi_cpufreq_driver);
370 return;
371}
372
373
374late_initcall(acpi_cpufreq_init);
375module_exit(acpi_cpufreq_exit);
376
377
