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12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/kernel.h>
15#include <linux/slab.h>
16#include <linux/module.h>
17#include <linux/init.h>
18#include <linux/cpufreq.h>
19#include <linux/proc_fs.h>
20#include <asm/io.h>
21#include <linux/uaccess.h>
22#include <asm/pal.h>
23
24#include <linux/acpi.h>
25#include <acpi/processor.h>
26
27MODULE_AUTHOR("Venkatesh Pallipadi");
28MODULE_DESCRIPTION("ACPI Processor P-States Driver");
29MODULE_LICENSE("GPL");
30
31struct cpufreq_acpi_io {
32 struct acpi_processor_performance acpi_data;
33 unsigned int resume;
34};
35
36struct cpufreq_acpi_req {
37 unsigned int cpu;
38 unsigned int state;
39};
40
41static struct cpufreq_acpi_io *acpi_io_data[NR_CPUS];
42
43static struct cpufreq_driver acpi_cpufreq_driver;
44
45
46static int
47processor_set_pstate (
48 u32 value)
49{
50 s64 retval;
51
52 pr_debug("processor_set_pstate\n");
53
54 retval = ia64_pal_set_pstate((u64)value);
55
56 if (retval) {
57 pr_debug("Failed to set freq to 0x%x, with error 0x%llx\n",
58 value, retval);
59 return -ENODEV;
60 }
61 return (int)retval;
62}
63
64
65static int
66processor_get_pstate (
67 u32 *value)
68{
69 u64 pstate_index = 0;
70 s64 retval;
71
72 pr_debug("processor_get_pstate\n");
73
74 retval = ia64_pal_get_pstate(&pstate_index,
75 PAL_GET_PSTATE_TYPE_INSTANT);
76 *value = (u32) pstate_index;
77
78 if (retval)
79 pr_debug("Failed to get current freq with "
80 "error 0x%llx, idx 0x%x\n", retval, *value);
81
82 return (int)retval;
83}
84
85
86
87static unsigned
88extract_clock (
89 struct cpufreq_acpi_io *data,
90 unsigned value)
91{
92 unsigned long i;
93
94 pr_debug("extract_clock\n");
95
96 for (i = 0; i < data->acpi_data.state_count; i++) {
97 if (value == data->acpi_data.states[i].status)
98 return data->acpi_data.states[i].core_frequency;
99 }
100 return data->acpi_data.states[i-1].core_frequency;
101}
102
103
104static long
105processor_get_freq (
106 void *arg)
107{
108 struct cpufreq_acpi_req *req = arg;
109 unsigned int cpu = req->cpu;
110 struct cpufreq_acpi_io *data = acpi_io_data[cpu];
111 u32 value;
112 int ret;
113
114 pr_debug("processor_get_freq\n");
115 if (smp_processor_id() != cpu)
116 return -EAGAIN;
117
118
119 ret = processor_get_pstate(&value);
120 if (ret) {
121 pr_warn("get performance failed with error %d\n", ret);
122 return ret;
123 }
124 return 1000 * extract_clock(data, value);
125}
126
127
128static long
129processor_set_freq (
130 void *arg)
131{
132 struct cpufreq_acpi_req *req = arg;
133 unsigned int cpu = req->cpu;
134 struct cpufreq_acpi_io *data = acpi_io_data[cpu];
135 int ret, state = req->state;
136 u32 value;
137
138 pr_debug("processor_set_freq\n");
139 if (smp_processor_id() != cpu)
140 return -EAGAIN;
141
142 if (state == data->acpi_data.state) {
143 if (unlikely(data->resume)) {
144 pr_debug("Called after resume, resetting to P%d\n", state);
145 data->resume = 0;
146 } else {
147 pr_debug("Already at target state (P%d)\n", state);
148 return 0;
149 }
150 }
151
152 pr_debug("Transitioning from P%d to P%d\n",
153 data->acpi_data.state, state);
154
155
156
157
158
159 value = (u32) data->acpi_data.states[state].control;
160
161 pr_debug("Transitioning to state: 0x%08x\n", value);
162
163 ret = processor_set_pstate(value);
164 if (ret) {
165 pr_warn("Transition failed with error %d\n", ret);
166 return -ENODEV;
167 }
168
169 data->acpi_data.state = state;
170 return 0;
171}
172
173
174static unsigned int
175acpi_cpufreq_get (
176 unsigned int cpu)
177{
178 struct cpufreq_acpi_req req;
179 long ret;
180
181 req.cpu = cpu;
182 ret = work_on_cpu(cpu, processor_get_freq, &req);
183
184 return ret > 0 ? (unsigned int) ret : 0;
185}
186
187
188static int
189acpi_cpufreq_target (
190 struct cpufreq_policy *policy,
191 unsigned int index)
192{
193 struct cpufreq_acpi_req req;
194
195 req.cpu = policy->cpu;
196 req.state = index;
197
198 return work_on_cpu(req.cpu, processor_set_freq, &req);
199}
200
201static int
202acpi_cpufreq_cpu_init (
203 struct cpufreq_policy *policy)
204{
205 unsigned int i;
206 unsigned int cpu = policy->cpu;
207 struct cpufreq_acpi_io *data;
208 unsigned int result = 0;
209 struct cpufreq_frequency_table *freq_table;
210
211 pr_debug("acpi_cpufreq_cpu_init\n");
212
213 data = kzalloc(sizeof(*data), GFP_KERNEL);
214 if (!data)
215 return (-ENOMEM);
216
217 acpi_io_data[cpu] = data;
218
219 result = acpi_processor_register_performance(&data->acpi_data, cpu);
220
221 if (result)
222 goto err_free;
223
224
225 if (data->acpi_data.state_count <= 1) {
226 pr_debug("No P-States\n");
227 result = -ENODEV;
228 goto err_unreg;
229 }
230
231 if ((data->acpi_data.control_register.space_id !=
232 ACPI_ADR_SPACE_FIXED_HARDWARE) ||
233 (data->acpi_data.status_register.space_id !=
234 ACPI_ADR_SPACE_FIXED_HARDWARE)) {
235 pr_debug("Unsupported address space [%d, %d]\n",
236 (u32) (data->acpi_data.control_register.space_id),
237 (u32) (data->acpi_data.status_register.space_id));
238 result = -ENODEV;
239 goto err_unreg;
240 }
241
242
243 freq_table = kcalloc(data->acpi_data.state_count + 1,
244 sizeof(*freq_table),
245 GFP_KERNEL);
246 if (!freq_table) {
247 result = -ENOMEM;
248 goto err_unreg;
249 }
250
251
252 policy->cpuinfo.transition_latency = 0;
253 for (i=0; i<data->acpi_data.state_count; i++) {
254 if ((data->acpi_data.states[i].transition_latency * 1000) >
255 policy->cpuinfo.transition_latency) {
256 policy->cpuinfo.transition_latency =
257 data->acpi_data.states[i].transition_latency * 1000;
258 }
259 }
260
261
262 for (i = 0; i <= data->acpi_data.state_count; i++)
263 {
264 if (i < data->acpi_data.state_count) {
265 freq_table[i].frequency =
266 data->acpi_data.states[i].core_frequency * 1000;
267 } else {
268 freq_table[i].frequency = CPUFREQ_TABLE_END;
269 }
270 }
271
272 policy->freq_table = freq_table;
273
274
275 acpi_processor_notify_smm(THIS_MODULE);
276
277 pr_info("CPU%u - ACPI performance management activated\n", cpu);
278
279 for (i = 0; i < data->acpi_data.state_count; i++)
280 pr_debug(" %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
281 (i == data->acpi_data.state?'*':' '), i,
282 (u32) data->acpi_data.states[i].core_frequency,
283 (u32) data->acpi_data.states[i].power,
284 (u32) data->acpi_data.states[i].transition_latency,
285 (u32) data->acpi_data.states[i].bus_master_latency,
286 (u32) data->acpi_data.states[i].status,
287 (u32) data->acpi_data.states[i].control);
288
289
290
291 data->resume = 1;
292
293 return (result);
294
295 err_unreg:
296 acpi_processor_unregister_performance(cpu);
297 err_free:
298 kfree(data);
299 acpi_io_data[cpu] = NULL;
300
301 return (result);
302}
303
304
305static int
306acpi_cpufreq_cpu_exit (
307 struct cpufreq_policy *policy)
308{
309 struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
310
311 pr_debug("acpi_cpufreq_cpu_exit\n");
312
313 if (data) {
314 acpi_io_data[policy->cpu] = NULL;
315 acpi_processor_unregister_performance(policy->cpu);
316 kfree(policy->freq_table);
317 kfree(data);
318 }
319
320 return (0);
321}
322
323
324static struct cpufreq_driver acpi_cpufreq_driver = {
325 .verify = cpufreq_generic_frequency_table_verify,
326 .target_index = acpi_cpufreq_target,
327 .get = acpi_cpufreq_get,
328 .init = acpi_cpufreq_cpu_init,
329 .exit = acpi_cpufreq_cpu_exit,
330 .name = "acpi-cpufreq",
331 .attr = cpufreq_generic_attr,
332};
333
334
335static int __init
336acpi_cpufreq_init (void)
337{
338 pr_debug("acpi_cpufreq_init\n");
339
340 return cpufreq_register_driver(&acpi_cpufreq_driver);
341}
342
343
344static void __exit
345acpi_cpufreq_exit (void)
346{
347 pr_debug("acpi_cpufreq_exit\n");
348
349 cpufreq_unregister_driver(&acpi_cpufreq_driver);
350}
351
352late_initcall(acpi_cpufreq_init);
353module_exit(acpi_cpufreq_exit);
354
