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 	unsigned int				resume;
33 };
34 
35 static struct cpufreq_acpi_io	*acpi_io_data[NR_CPUS];
36 
37 static struct cpufreq_driver acpi_cpufreq_driver;
38 
39 
40 static int
41 processor_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 
59 static int
60 processor_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 */
81 static unsigned
82 extract_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 
99 static unsigned int
100 processor_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 
129 migrate_end:
130 	set_cpus_allowed_ptr(current, &saved_mask);
131 	return ret;
132 }
133 
134 
135 static int
136 processor_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 
189 migrate_end:
190 	set_cpus_allowed_ptr(current, &saved_mask);
191 	return (retval);
192 }
193 
194 
195 static unsigned int
196 acpi_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 
207 static int
208 acpi_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 
215 static int
216 acpi_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 
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(policy->cpu);
336 		kfree(policy->freq_table);
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