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#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	unsigned int				resume;
 33};
 34
 35static struct cpufreq_acpi_io	*acpi_io_data[NR_CPUS];
 36
 37static struct cpufreq_driver acpi_cpufreq_driver;
 38
 39
 40static int
 41processor_set_pstate (
 42	u32	value)
 43{
 44	s64 retval;
 45
 46	pr_debug("processor_set_pstate\n");
 47
 48	retval = ia64_pal_set_pstate((u64)value);
 49
 50	if (retval) {
 51		pr_debug("Failed to set freq to 0x%x, with error 0x%lx\n",
 52		        value, retval);
 53		return -ENODEV;
 54	}
 55	return (int)retval;
 56}
 57
 58
 59static int
 60processor_get_pstate (
 61	u32	*value)
 62{
 63	u64	pstate_index = 0;
 64	s64 	retval;
 65
 66	pr_debug("processor_get_pstate\n");
 67
 68	retval = ia64_pal_get_pstate(&pstate_index,
 69	                             PAL_GET_PSTATE_TYPE_INSTANT);
 70	*value = (u32) pstate_index;
 71
 72	if (retval)
 73		pr_debug("Failed to get current freq with "
 74			"error 0x%lx, idx 0x%x\n", retval, *value);
 75
 76	return (int)retval;
 77}
 78
 79
 80/* To be used only after data->acpi_data is initialized */
 81static unsigned
 82extract_clock (
 83	struct cpufreq_acpi_io *data,
 84	unsigned value,
 85	unsigned int cpu)
 86{
 87	unsigned long i;
 88
 89	pr_debug("extract_clock\n");
 90
 91	for (i = 0; i < data->acpi_data.state_count; i++) {
 92		if (value == data->acpi_data.states[i].status)
 93			return data->acpi_data.states[i].core_frequency;
 94	}
 95	return data->acpi_data.states[i-1].core_frequency;
 96}
 97
 98
 99static unsigned int
100processor_get_freq (
101	struct cpufreq_acpi_io	*data,
102	unsigned int		cpu)
103{
104	int			ret = 0;
105	u32			value = 0;
106	cpumask_t		saved_mask;
107	unsigned long 		clock_freq;
108
109	pr_debug("processor_get_freq\n");
110
111	saved_mask = current->cpus_allowed;
112	set_cpus_allowed_ptr(current, cpumask_of(cpu));
113	if (smp_processor_id() != cpu)
114		goto migrate_end;
115
116	/* processor_get_pstate gets the instantaneous frequency */
117	ret = processor_get_pstate(&value);
118
119	if (ret) {
120		set_cpus_allowed_ptr(current, &saved_mask);
121		printk(KERN_WARNING "get performance failed with error %d\n",
122		       ret);
123		ret = 0;
124		goto migrate_end;
125	}
126	clock_freq = extract_clock(data, value, cpu);
127	ret = (clock_freq*1000);
128
129migrate_end:
130	set_cpus_allowed_ptr(current, &saved_mask);
131	return ret;
132}
133
134
135static int
136processor_set_freq (
137	struct cpufreq_acpi_io	*data,
138	struct cpufreq_policy   *policy,
139	int			state)
140{
141	int			ret = 0;
142	u32			value = 0;
143	cpumask_t		saved_mask;
144	int			retval;
145
146	pr_debug("processor_set_freq\n");
147
148	saved_mask = current->cpus_allowed;
149	set_cpus_allowed_ptr(current, cpumask_of(policy->cpu));
150	if (smp_processor_id() != policy->cpu) {
151		retval = -EAGAIN;
152		goto migrate_end;
153	}
154
155	if (state == data->acpi_data.state) {
156		if (unlikely(data->resume)) {
157			pr_debug("Called after resume, resetting to P%d\n", state);
158			data->resume = 0;
159		} else {
160			pr_debug("Already at target state (P%d)\n", state);
161			retval = 0;
162			goto migrate_end;
163		}
164	}
165
166	pr_debug("Transitioning from P%d to P%d\n",
167		data->acpi_data.state, state);
168
169	/*
170	 * First we write the target state's 'control' value to the
171	 * control_register.
172	 */
173
174	value = (u32) data->acpi_data.states[state].control;
175
176	pr_debug("Transitioning to state: 0x%08x\n", value);
177
178	ret = processor_set_pstate(value);
179	if (ret) {
180		printk(KERN_WARNING "Transition failed with error %d\n", ret);
181		retval = -ENODEV;
182		goto migrate_end;
183	}
184
185	data->acpi_data.state = state;
186
187	retval = 0;
188
189migrate_end:
190	set_cpus_allowed_ptr(current, &saved_mask);
191	return (retval);
192}
193
194
195static unsigned int
196acpi_cpufreq_get (
197	unsigned int		cpu)
198{
199	struct cpufreq_acpi_io *data = acpi_io_data[cpu];
200
201	pr_debug("acpi_cpufreq_get\n");
202
203	return processor_get_freq(data, cpu);
204}
205
206
207static int
208acpi_cpufreq_target (
209	struct cpufreq_policy   *policy,
210	unsigned int index)
211{
212	return processor_set_freq(acpi_io_data[policy->cpu], policy, index);
213}
214
215static int
216acpi_cpufreq_cpu_init (
217	struct cpufreq_policy   *policy)
218{
219	unsigned int		i;
220	unsigned int		cpu = policy->cpu;
221	struct cpufreq_acpi_io	*data;
222	unsigned int		result = 0;
223	struct cpufreq_frequency_table *freq_table;
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	/* capability check */
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	/* alloc freq_table */
257	freq_table = kzalloc(sizeof(*freq_table) *
258	                           (data->acpi_data.state_count + 1),
259	                           GFP_KERNEL);
260	if (!freq_table) {
261		result = -ENOMEM;
262		goto err_unreg;
263	}
264
265	/* detect transition latency */
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	/* table init */
276	for (i = 0; i <= data->acpi_data.state_count; i++)
277	{
278		if (i < data->acpi_data.state_count) {
279			freq_table[i].frequency =
280			      data->acpi_data.states[i].core_frequency * 1000;
281		} else {
282			freq_table[i].frequency = CPUFREQ_TABLE_END;
283		}
284	}
285
286	result = cpufreq_table_validate_and_show(policy, freq_table);
287	if (result) {
288		goto err_freqfree;
289	}
290
291	/* notify BIOS that we exist */
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	/* 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
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(policy->cpu);
336		kfree(policy->freq_table);
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