GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / cpufreq / ia64-acpi-cpufreq.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/cpufreq.h>
19 #include <linux/proc_fs.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 struct cpufreq_acpi_io {
32         struct acpi_processor_performance       acpi_data;
33         unsigned int                            resume;
34 };
35
36 struct cpufreq_acpi_req {
37         unsigned int            cpu;
38         unsigned int            state;
39 };
40
41 static struct cpufreq_acpi_io   *acpi_io_data[NR_CPUS];
42
43 static struct cpufreq_driver acpi_cpufreq_driver;
44
45
46 static int
47 processor_set_pstate (
48         u32     value)
49 {
50         s64 retval;
51
52         pr_debug("processor_set_pstate\n");
53
54         retval = ia64_pal_set_pstate((u64)value);
55
56         if (retval) {
57                 pr_debug("Failed to set freq to 0x%x, with error 0x%llx\n",
58                         value, retval);
59                 return -ENODEV;
60         }
61         return (int)retval;
62 }
63
64
65 static int
66 processor_get_pstate (
67         u32     *value)
68 {
69         u64     pstate_index = 0;
70         s64     retval;
71
72         pr_debug("processor_get_pstate\n");
73
74         retval = ia64_pal_get_pstate(&pstate_index,
75                                      PAL_GET_PSTATE_TYPE_INSTANT);
76         *value = (u32) pstate_index;
77
78         if (retval)
79                 pr_debug("Failed to get current freq with "
80                         "error 0x%llx, idx 0x%x\n", retval, *value);
81
82         return (int)retval;
83 }
84
85
86 /* To be used only after data->acpi_data is initialized */
87 static unsigned
88 extract_clock (
89         struct cpufreq_acpi_io *data,
90         unsigned value)
91 {
92         unsigned long i;
93
94         pr_debug("extract_clock\n");
95
96         for (i = 0; i < data->acpi_data.state_count; i++) {
97                 if (value == data->acpi_data.states[i].status)
98                         return data->acpi_data.states[i].core_frequency;
99         }
100         return data->acpi_data.states[i-1].core_frequency;
101 }
102
103
104 static long
105 processor_get_freq (
106         void *arg)
107 {
108         struct cpufreq_acpi_req *req = arg;
109         unsigned int            cpu = req->cpu;
110         struct cpufreq_acpi_io  *data = acpi_io_data[cpu];
111         u32                     value;
112         int                     ret;
113
114         pr_debug("processor_get_freq\n");
115         if (smp_processor_id() != cpu)
116                 return -EAGAIN;
117
118         /* processor_get_pstate gets the instantaneous frequency */
119         ret = processor_get_pstate(&value);
120         if (ret) {
121                 pr_warn("get performance failed with error %d\n", ret);
122                 return ret;
123         }
124         return 1000 * extract_clock(data, value);
125 }
126
127
128 static long
129 processor_set_freq (
130         void *arg)
131 {
132         struct cpufreq_acpi_req *req = arg;
133         unsigned int            cpu = req->cpu;
134         struct cpufreq_acpi_io  *data = acpi_io_data[cpu];
135         int                     ret, state = req->state;
136         u32                     value;
137
138         pr_debug("processor_set_freq\n");
139         if (smp_processor_id() != cpu)
140                 return -EAGAIN;
141
142         if (state == data->acpi_data.state) {
143                 if (unlikely(data->resume)) {
144                         pr_debug("Called after resume, resetting to P%d\n", state);
145                         data->resume = 0;
146                 } else {
147                         pr_debug("Already at target state (P%d)\n", state);
148                         return 0;
149                 }
150         }
151
152         pr_debug("Transitioning from P%d to P%d\n",
153                 data->acpi_data.state, state);
154
155         /*
156          * First we write the target state's 'control' value to the
157          * control_register.
158          */
159         value = (u32) data->acpi_data.states[state].control;
160
161         pr_debug("Transitioning to state: 0x%08x\n", value);
162
163         ret = processor_set_pstate(value);
164         if (ret) {
165                 pr_warn("Transition failed with error %d\n", ret);
166                 return -ENODEV;
167         }
168
169         data->acpi_data.state = state;
170         return 0;
171 }
172
173
174 static unsigned int
175 acpi_cpufreq_get (
176         unsigned int            cpu)
177 {
178         struct cpufreq_acpi_req req;
179         long ret;
180
181         req.cpu = cpu;
182         ret = work_on_cpu(cpu, processor_get_freq, &req);
183
184         return ret > 0 ? (unsigned int) ret : 0;
185 }
186
187
188 static int
189 acpi_cpufreq_target (
190         struct cpufreq_policy   *policy,
191         unsigned int index)
192 {
193         struct cpufreq_acpi_req req;
194
195         req.cpu = policy->cpu;
196         req.state = index;
197
198         return work_on_cpu(req.cpu, processor_set_freq, &req);
199 }
200
201 static int
202 acpi_cpufreq_cpu_init (
203         struct cpufreq_policy   *policy)
204 {
205         unsigned int            i;
206         unsigned int            cpu = policy->cpu;
207         struct cpufreq_acpi_io  *data;
208         unsigned int            result = 0;
209         struct cpufreq_frequency_table *freq_table;
210
211         pr_debug("acpi_cpufreq_cpu_init\n");
212
213         data = kzalloc(sizeof(*data), GFP_KERNEL);
214         if (!data)
215                 return (-ENOMEM);
216
217         acpi_io_data[cpu] = data;
218
219         result = acpi_processor_register_performance(&data->acpi_data, cpu);
220
221         if (result)
222                 goto err_free;
223
224         /* capability check */
225         if (data->acpi_data.state_count <= 1) {
226                 pr_debug("No P-States\n");
227                 result = -ENODEV;
228                 goto err_unreg;
229         }
230
231         if ((data->acpi_data.control_register.space_id !=
232                                         ACPI_ADR_SPACE_FIXED_HARDWARE) ||
233             (data->acpi_data.status_register.space_id !=
234                                         ACPI_ADR_SPACE_FIXED_HARDWARE)) {
235                 pr_debug("Unsupported address space [%d, %d]\n",
236                         (u32) (data->acpi_data.control_register.space_id),
237                         (u32) (data->acpi_data.status_register.space_id));
238                 result = -ENODEV;
239                 goto err_unreg;
240         }
241
242         /* alloc freq_table */
243         freq_table = kcalloc(data->acpi_data.state_count + 1,
244                                    sizeof(*freq_table),
245                                    GFP_KERNEL);
246         if (!freq_table) {
247                 result = -ENOMEM;
248                 goto err_unreg;
249         }
250
251         /* detect transition latency */
252         policy->cpuinfo.transition_latency = 0;
253         for (i=0; i<data->acpi_data.state_count; i++) {
254                 if ((data->acpi_data.states[i].transition_latency * 1000) >
255                     policy->cpuinfo.transition_latency) {
256                         policy->cpuinfo.transition_latency =
257                             data->acpi_data.states[i].transition_latency * 1000;
258                 }
259         }
260
261         /* table init */
262         for (i = 0; i <= data->acpi_data.state_count; i++)
263         {
264                 if (i < data->acpi_data.state_count) {
265                         freq_table[i].frequency =
266                               data->acpi_data.states[i].core_frequency * 1000;
267                 } else {
268                         freq_table[i].frequency = CPUFREQ_TABLE_END;
269                 }
270         }
271
272         policy->freq_table = freq_table;
273
274         /* notify BIOS that we exist */
275         acpi_processor_notify_smm(THIS_MODULE);
276
277         pr_info("CPU%u - ACPI performance management activated\n", cpu);
278
279         for (i = 0; i < data->acpi_data.state_count; i++)
280                 pr_debug("     %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
281                         (i == data->acpi_data.state?'*':' '), i,
282                         (u32) data->acpi_data.states[i].core_frequency,
283                         (u32) data->acpi_data.states[i].power,
284                         (u32) data->acpi_data.states[i].transition_latency,
285                         (u32) data->acpi_data.states[i].bus_master_latency,
286                         (u32) data->acpi_data.states[i].status,
287                         (u32) data->acpi_data.states[i].control);
288
289         /* the first call to ->target() should result in us actually
290          * writing something to the appropriate registers. */
291         data->resume = 1;
292
293         return (result);
294
295  err_unreg:
296         acpi_processor_unregister_performance(cpu);
297  err_free:
298         kfree(data);
299         acpi_io_data[cpu] = NULL;
300
301         return (result);
302 }
303
304
305 static int
306 acpi_cpufreq_cpu_exit (
307         struct cpufreq_policy   *policy)
308 {
309         struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
310
311         pr_debug("acpi_cpufreq_cpu_exit\n");
312
313         if (data) {
314                 acpi_io_data[policy->cpu] = NULL;
315                 acpi_processor_unregister_performance(policy->cpu);
316                 kfree(policy->freq_table);
317                 kfree(data);
318         }
319
320         return (0);
321 }
322
323
324 static struct cpufreq_driver acpi_cpufreq_driver = {
325         .verify         = cpufreq_generic_frequency_table_verify,
326         .target_index   = acpi_cpufreq_target,
327         .get            = acpi_cpufreq_get,
328         .init           = acpi_cpufreq_cpu_init,
329         .exit           = acpi_cpufreq_cpu_exit,
330         .name           = "acpi-cpufreq",
331         .attr           = cpufreq_generic_attr,
332 };
333
334
335 static int __init
336 acpi_cpufreq_init (void)
337 {
338         pr_debug("acpi_cpufreq_init\n");
339
340         return cpufreq_register_driver(&acpi_cpufreq_driver);
341 }
342
343
344 static void __exit
345 acpi_cpufreq_exit (void)
346 {
347         pr_debug("acpi_cpufreq_exit\n");
348
349         cpufreq_unregister_driver(&acpi_cpufreq_driver);
350 }
351
352 late_initcall(acpi_cpufreq_init);
353 module_exit(acpi_cpufreq_exit);