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 
25 MODULE_AUTHOR("Venkatesh Pallipadi");
26 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
27 MODULE_LICENSE("GPL");
28 
29 
30 struct cpufreq_acpi_io {
31 	struct acpi_processor_performance	acpi_data;
32 	struct cpufreq_frequency_table		*freq_table;
33 	unsigned int				resume;
34 };
35 
36 static struct cpufreq_acpi_io	*acpi_io_data[NR_CPUS];
37 
38 static struct cpufreq_driver acpi_cpufreq_driver;
39 
40 
41 static int
42 processor_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 
60 static int
61 processor_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 /* To be used only after data->acpi_data is initialized */
82 static unsigned
83 extract_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 
100 static unsigned int
101 processor_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 	/* processor_get_pstate gets the instantaneous frequency */
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 
130 migrate_end:
131 	set_cpus_allowed_ptr(current, &saved_mask);
132 	return ret;
133 }
134 
135 
136 static int
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 		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 
190 migrate_end:
191 	set_cpus_allowed_ptr(current, &saved_mask);
192 	return (retval);
193 }
194 
195 
196 static unsigned int
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
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
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 
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 	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 	/* 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 			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 	/* 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(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 
325 static int
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(&data->acpi_data,
336 		                                      policy->cpu);
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
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
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