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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/cpufreq.h>
18 #include <linux/proc_fs.h>
19 #include <linux/seq_file.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 
27 MODULE_AUTHOR("Venkatesh Pallipadi");
28 MODULE_DESCRIPTION("ACPI Processor P-States Driver");
29 MODULE_LICENSE("GPL");
30 
31 
32 struct cpufreq_acpi_io {
33 	struct acpi_processor_performance	acpi_data;
34 	unsigned int				resume;
35 };
36 
37 static struct cpufreq_acpi_io	*acpi_io_data[NR_CPUS];
38 
39 static struct cpufreq_driver acpi_cpufreq_driver;
40 
41 
42 static int
43 processor_set_pstate (
44 	u32	value)
45 {
46 	s64 retval;
47 
48 	pr_debug("processor_set_pstate\n");
49 
50 	retval = ia64_pal_set_pstate((u64)value);
51 
52 	if (retval) {
53 		pr_debug("Failed to set freq to 0x%x, with error 0x%lx\n",
54 		        value, retval);
55 		return -ENODEV;
56 	}
57 	return (int)retval;
58 }
59 
60 
61 static int
62 processor_get_pstate (
63 	u32	*value)
64 {
65 	u64	pstate_index = 0;
66 	s64 	retval;
67 
68 	pr_debug("processor_get_pstate\n");
69 
70 	retval = ia64_pal_get_pstate(&pstate_index,
71 	                             PAL_GET_PSTATE_TYPE_INSTANT);
72 	*value = (u32) pstate_index;
73 
74 	if (retval)
75 		pr_debug("Failed to get current freq with "
76 			"error 0x%lx, idx 0x%x\n", retval, *value);
77 
78 	return (int)retval;
79 }
80 
81 
82 /* To be used only after data->acpi_data is initialized */
83 static unsigned
84 extract_clock (
85 	struct cpufreq_acpi_io *data,
86 	unsigned value,
87 	unsigned int cpu)
88 {
89 	unsigned long i;
90 
91 	pr_debug("extract_clock\n");
92 
93 	for (i = 0; i < data->acpi_data.state_count; i++) {
94 		if (value == data->acpi_data.states[i].status)
95 			return data->acpi_data.states[i].core_frequency;
96 	}
97 	return data->acpi_data.states[i-1].core_frequency;
98 }
99 
100 
101 static unsigned int
102 processor_get_freq (
103 	struct cpufreq_acpi_io	*data,
104 	unsigned int		cpu)
105 {
106 	int			ret = 0;
107 	u32			value = 0;
108 	cpumask_t		saved_mask;
109 	unsigned long 		clock_freq;
110 
111 	pr_debug("processor_get_freq\n");
112 
113 	saved_mask = current->cpus_allowed;
114 	set_cpus_allowed_ptr(current, cpumask_of(cpu));
115 	if (smp_processor_id() != cpu)
116 		goto migrate_end;
117 
118 	/* processor_get_pstate gets the instantaneous frequency */
119 	ret = processor_get_pstate(&value);
120 
121 	if (ret) {
122 		set_cpus_allowed_ptr(current, &saved_mask);
123 		pr_warn("get performance failed with error %d\n", 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 		pr_warn("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 	struct cpufreq_frequency_table *freq_table;
225 
226 	pr_debug("acpi_cpufreq_cpu_init\n");
227 
228 	data = kzalloc(sizeof(*data), GFP_KERNEL);
229 	if (!data)
230 		return (-ENOMEM);
231 
232 	acpi_io_data[cpu] = data;
233 
234 	result = acpi_processor_register_performance(&data->acpi_data, cpu);
235 
236 	if (result)
237 		goto err_free;
238 
239 	/* capability check */
240 	if (data->acpi_data.state_count <= 1) {
241 		pr_debug("No P-States\n");
242 		result = -ENODEV;
243 		goto err_unreg;
244 	}
245 
246 	if ((data->acpi_data.control_register.space_id !=
247 					ACPI_ADR_SPACE_FIXED_HARDWARE) ||
248 	    (data->acpi_data.status_register.space_id !=
249 					ACPI_ADR_SPACE_FIXED_HARDWARE)) {
250 		pr_debug("Unsupported address space [%d, %d]\n",
251 			(u32) (data->acpi_data.control_register.space_id),
252 			(u32) (data->acpi_data.status_register.space_id));
253 		result = -ENODEV;
254 		goto err_unreg;
255 	}
256 
257 	/* alloc freq_table */
258 	freq_table = kzalloc(sizeof(*freq_table) *
259 	                           (data->acpi_data.state_count + 1),
260 	                           GFP_KERNEL);
261 	if (!freq_table) {
262 		result = -ENOMEM;
263 		goto err_unreg;
264 	}
265 
266 	/* detect transition latency */
267 	policy->cpuinfo.transition_latency = 0;
268 	for (i=0; i<data->acpi_data.state_count; i++) {
269 		if ((data->acpi_data.states[i].transition_latency * 1000) >
270 		    policy->cpuinfo.transition_latency) {
271 			policy->cpuinfo.transition_latency =
272 			    data->acpi_data.states[i].transition_latency * 1000;
273 		}
274 	}
275 
276 	/* table init */
277 	for (i = 0; i <= data->acpi_data.state_count; i++)
278 	{
279 		if (i < data->acpi_data.state_count) {
280 			freq_table[i].frequency =
281 			      data->acpi_data.states[i].core_frequency * 1000;
282 		} else {
283 			freq_table[i].frequency = CPUFREQ_TABLE_END;
284 		}
285 	}
286 
287 	result = cpufreq_table_validate_and_show(policy, freq_table);
288 	if (result) {
289 		goto err_freqfree;
290 	}
291 
292 	/* notify BIOS that we exist */
293 	acpi_processor_notify_smm(THIS_MODULE);
294 
295 	pr_info("CPU%u - ACPI performance management 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