1/*
2 * arch/ia64/kernel/cpufreq/acpi-cpufreq.c
3 * This file provides the ACPI based P-state support. This
4 * module works with generic cpufreq infrastructure. Most of
5 * the code is based on i386 version
6 * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)
7 *
8 * Copyright (C) 2005 Intel Corp
9 *      Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
10 */
11
12#include <linux/kernel.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
25#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "acpi-cpufreq", msg)
26
27MODULE_AUTHOR("Venkatesh Pallipadi");
28MODULE_DESCRIPTION("ACPI Processor P-States Driver");
29MODULE_LICENSE("GPL");
30
31
32struct cpufreq_acpi_io {
33	struct acpi_processor_performance	acpi_data;
34	struct cpufreq_frequency_table		*freq_table;
35	unsigned int				resume;
36};
37
38static struct cpufreq_acpi_io	*acpi_io_data[NR_CPUS];
39
40static struct cpufreq_driver acpi_cpufreq_driver;
41
42
43static int
44processor_set_pstate (
45	u32	value)
46{
47	s64 retval;
48
49	dprintk("processor_set_pstate\n");
50
51	retval = ia64_pal_set_pstate((u64)value);
52
53	if (retval) {
54		dprintk("Failed to set freq to 0x%x, with error 0x%x\n",
55		        value, retval);
56		return -ENODEV;
57	}
58	return (int)retval;
59}
60
61
62static int
63processor_get_pstate (
64	u32	*value)
65{
66	u64	pstate_index = 0;
67	s64 	retval;
68
69	dprintk("processor_get_pstate\n");
70
71	retval = ia64_pal_get_pstate(&pstate_index,
72	                             PAL_GET_PSTATE_TYPE_INSTANT);
73	*value = (u32) pstate_index;
74
75	if (retval)
76		dprintk("Failed to get current freq with "
77		        "error 0x%x, idx 0x%x\n", retval, *value);
78
79	return (int)retval;
80}
81
82
83/* To be used only after data->acpi_data is initialized */
84static unsigned
85extract_clock (
86	struct cpufreq_acpi_io *data,
87	unsigned value,
88	unsigned int cpu)
89{
90	unsigned long i;
91
92	dprintk("extract_clock\n");
93
94	for (i = 0; i < data->acpi_data.state_count; i++) {
95		if (value == data->acpi_data.states[i].status)
96			return data->acpi_data.states[i].core_frequency;
97	}
98	return data->acpi_data.states[i-1].core_frequency;
99}
100
101
102static unsigned int
103processor_get_freq (
104	struct cpufreq_acpi_io	*data,
105	unsigned int		cpu)
106{
107	int			ret = 0;
108	u32			value = 0;
109	cpumask_t		saved_mask;
110	unsigned long 		clock_freq;
111
112	dprintk("processor_get_freq\n");
113
114	saved_mask = current->cpus_allowed;
115	set_cpus_allowed(current, cpumask_of_cpu(cpu));
116	if (smp_processor_id() != cpu) {
117		ret = -EAGAIN;
118		goto migrate_end;
119	}
120
121	/* processor_get_pstate gets the instantaneous frequency */
122	ret = processor_get_pstate(&value);
123
124	if (ret) {
125		set_cpus_allowed(current, saved_mask);
126		printk(KERN_WARNING "get performance failed with error %d\n",
127		       ret);
128		ret = -EAGAIN;
129		goto migrate_end;
130	}
131	clock_freq = extract_clock(data, value, cpu);
132	ret = (clock_freq*1000);
133
134migrate_end:
135	set_cpus_allowed(current, saved_mask);
136	return ret;
137}
138
139
140static int
141processor_set_freq (
142	struct cpufreq_acpi_io	*data,
143	unsigned int		cpu,
144	int			state)
145{
146	int			ret = 0;
147	u32			value = 0;
148	struct cpufreq_freqs    cpufreq_freqs;
149	cpumask_t		saved_mask;
150	int			retval;
151
152	dprintk("processor_set_freq\n");
153
154	saved_mask = current->cpus_allowed;
155	set_cpus_allowed(current, cpumask_of_cpu(cpu));
156	if (smp_processor_id() != cpu) {
157		retval = -EAGAIN;
158		goto migrate_end;
159	}
160
161	if (state == data->acpi_data.state) {
162		if (unlikely(data->resume)) {
163			dprintk("Called after resume, resetting to P%d\n", state);
164			data->resume = 0;
165		} else {
166			dprintk("Already at target state (P%d)\n", state);
167			retval = 0;
168			goto migrate_end;
169		}
170	}
171
172	dprintk("Transitioning from P%d to P%d\n",
173		data->acpi_data.state, state);
174
175	/* cpufreq frequency struct */
176	cpufreq_freqs.cpu = cpu;
177	cpufreq_freqs.old = data->freq_table[data->acpi_data.state].frequency;
178	cpufreq_freqs.new = data->freq_table[state].frequency;
179
180	/* notify cpufreq */
181	cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
182
183	/*
184	 * First we write the target state's 'control' value to the
185	 * control_register.
186	 */
187
188	value = (u32) data->acpi_data.states[state].control;
189
190	dprintk("Transitioning to state: 0x%08x\n", value);
191
192	ret = processor_set_pstate(value);
193	if (ret) {
194		unsigned int tmp = cpufreq_freqs.new;
195		cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
196		cpufreq_freqs.new = cpufreq_freqs.old;
197		cpufreq_freqs.old = tmp;
198		cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_PRECHANGE);
199		cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
200		printk(KERN_WARNING "Transition failed with error %d\n", ret);
201		retval = -ENODEV;
202		goto migrate_end;
203	}
204
205	cpufreq_notify_transition(&cpufreq_freqs, CPUFREQ_POSTCHANGE);
206
207	data->acpi_data.state = state;
208
209	retval = 0;
210
211migrate_end:
212	set_cpus_allowed(current, saved_mask);
213	return (retval);
214}
215
216
217static unsigned int
218acpi_cpufreq_get (
219	unsigned int		cpu)
220{
221	struct cpufreq_acpi_io *data = acpi_io_data[cpu];
222
223	dprintk("acpi_cpufreq_get\n");
224
225	return processor_get_freq(data, cpu);
226}
227
228
229static int
230acpi_cpufreq_target (
231	struct cpufreq_policy   *policy,
232	unsigned int target_freq,
233	unsigned int relation)
234{
235	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
236	unsigned int next_state = 0;
237	unsigned int result = 0;
238
239	dprintk("acpi_cpufreq_setpolicy\n");
240
241	result = cpufreq_frequency_table_target(policy,
242			data->freq_table, target_freq, relation, &next_state);
243	if (result)
244		return (result);
245
246	result = processor_set_freq(data, policy->cpu, next_state);
247
248	return (result);
249}
250
251
252static int
253acpi_cpufreq_verify (
254	struct cpufreq_policy   *policy)
255{
256	unsigned int result = 0;
257	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
258
259	dprintk("acpi_cpufreq_verify\n");
260
261	result = cpufreq_frequency_table_verify(policy,
262			data->freq_table);
263
264	return (result);
265}
266
267
268static int
269acpi_cpufreq_cpu_init (
270	struct cpufreq_policy   *policy)
271{
272	unsigned int		i;
273	unsigned int		cpu = policy->cpu;
274	struct cpufreq_acpi_io	*data;
275	unsigned int		result = 0;
276
277	dprintk("acpi_cpufreq_cpu_init\n");
278
279	data = kzalloc(sizeof(struct cpufreq_acpi_io), GFP_KERNEL);
280	if (!data)
281		return (-ENOMEM);
282
283	acpi_io_data[cpu] = data;
284
285	result = acpi_processor_register_performance(&data->acpi_data, cpu);
286
287	if (result)
288		goto err_free;
289
290	/* capability check */
291	if (data->acpi_data.state_count <= 1) {
292		dprintk("No P-States\n");
293		result = -ENODEV;
294		goto err_unreg;
295	}
296
297	if ((data->acpi_data.control_register.space_id !=
298					ACPI_ADR_SPACE_FIXED_HARDWARE) ||
299	    (data->acpi_data.status_register.space_id !=
300					ACPI_ADR_SPACE_FIXED_HARDWARE)) {
301		dprintk("Unsupported address space [%d, %d]\n",
302			(u32) (data->acpi_data.control_register.space_id),
303			(u32) (data->acpi_data.status_register.space_id));
304		result = -ENODEV;
305		goto err_unreg;
306	}
307
308	/* alloc freq_table */
309	data->freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) *
310	                           (data->acpi_data.state_count + 1),
311	                           GFP_KERNEL);
312	if (!data->freq_table) {
313		result = -ENOMEM;
314		goto err_unreg;
315	}
316
317	/* detect transition latency */
318	policy->cpuinfo.transition_latency = 0;
319	for (i=0; i<data->acpi_data.state_count; i++) {
320		if ((data->acpi_data.states[i].transition_latency * 1000) >
321		    policy->cpuinfo.transition_latency) {
322			policy->cpuinfo.transition_latency =
323			    data->acpi_data.states[i].transition_latency * 1000;
324		}
325	}
326	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
327
328	policy->cur = processor_get_freq(data, policy->cpu);
329
330	/* table init */
331	for (i = 0; i <= data->acpi_data.state_count; i++)
332	{
333		data->freq_table[i].index = i;
334		if (i < data->acpi_data.state_count) {
335			data->freq_table[i].frequency =
336			      data->acpi_data.states[i].core_frequency * 1000;
337		} else {
338			data->freq_table[i].frequency = CPUFREQ_TABLE_END;
339		}
340	}
341
342	result = cpufreq_frequency_table_cpuinfo(policy, data->freq_table);
343	if (result) {
344		goto err_freqfree;
345	}
346
347	/* notify BIOS that we exist */
348	acpi_processor_notify_smm(THIS_MODULE);
349
350	printk(KERN_INFO "acpi-cpufreq: CPU%u - ACPI performance management "
351	       "activated.\n", cpu);
352
353	for (i = 0; i < data->acpi_data.state_count; i++)
354		dprintk("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
355			(i == data->acpi_data.state?'*':' '), i,
356			(u32) data->acpi_data.states[i].core_frequency,
357			(u32) data->acpi_data.states[i].power,
358			(u32) data->acpi_data.states[i].transition_latency,
359			(u32) data->acpi_data.states[i].bus_master_latency,
360			(u32) data->acpi_data.states[i].status,
361			(u32) data->acpi_data.states[i].control);
362
363	cpufreq_frequency_table_get_attr(data->freq_table, policy->cpu);
364
365	/* the first call to ->target() should result in us actually
366	 * writing something to the appropriate registers. */
367	data->resume = 1;
368
369	return (result);
370
371 err_freqfree:
372	kfree(data->freq_table);
373 err_unreg:
374	acpi_processor_unregister_performance(&data->acpi_data, cpu);
375 err_free:
376	kfree(data);
377	acpi_io_data[cpu] = NULL;
378
379	return (result);
380}
381
382
383static int
384acpi_cpufreq_cpu_exit (
385	struct cpufreq_policy   *policy)
386{
387	struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
388
389	dprintk("acpi_cpufreq_cpu_exit\n");
390
391	if (data) {
392		cpufreq_frequency_table_put_attr(policy->cpu);
393		acpi_io_data[policy->cpu] = NULL;
394		acpi_processor_unregister_performance(&data->acpi_data,
395		                                      policy->cpu);
396		kfree(data);
397	}
398
399	return (0);
400}
401
402
403static struct freq_attr* acpi_cpufreq_attr[] = {
404	&cpufreq_freq_attr_scaling_available_freqs,
405	NULL,
406};
407
408
409static struct cpufreq_driver acpi_cpufreq_driver = {
410	.verify 	= acpi_cpufreq_verify,
411	.target 	= acpi_cpufreq_target,
412	.get 		= acpi_cpufreq_get,
413	.init		= acpi_cpufreq_cpu_init,
414	.exit		= acpi_cpufreq_cpu_exit,
415	.name		= "acpi-cpufreq",
416	.owner		= THIS_MODULE,
417	.attr           = acpi_cpufreq_attr,
418};
419
420
421static int __init
422acpi_cpufreq_init (void)
423{
424	dprintk("acpi_cpufreq_init\n");
425
426 	return cpufreq_register_driver(&acpi_cpufreq_driver);
427}
428
429
430static void __exit
431acpi_cpufreq_exit (void)
432{
433	dprintk("acpi_cpufreq_exit\n");
434
435	cpufreq_unregister_driver(&acpi_cpufreq_driver);
436	return;
437}
438
439
440late_initcall(acpi_cpufreq_init);
441module_exit(acpi_cpufreq_exit);
442