Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
[platform/kernel/linux-rpi.git] / drivers / cpufreq / e_powersaver.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Based on documentation provided by Dave Jones. Thanks!
4  *
5  *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
6  */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/cpufreq.h>
14 #include <linux/ioport.h>
15 #include <linux/slab.h>
16 #include <linux/timex.h>
17 #include <linux/io.h>
18 #include <linux/delay.h>
19
20 #include <asm/cpu_device_id.h>
21 #include <asm/msr.h>
22 #include <asm/tsc.h>
23
24 #if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
25 #include <linux/acpi.h>
26 #include <acpi/processor.h>
27 #endif
28
29 #define EPS_BRAND_C7M   0
30 #define EPS_BRAND_C7    1
31 #define EPS_BRAND_EDEN  2
32 #define EPS_BRAND_C3    3
33 #define EPS_BRAND_C7D   4
34
35 struct eps_cpu_data {
36         u32 fsb;
37 #if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
38         u32 bios_limit;
39 #endif
40         struct cpufreq_frequency_table freq_table[];
41 };
42
43 static struct eps_cpu_data *eps_cpu[NR_CPUS];
44
45 /* Module parameters */
46 static int freq_failsafe_off;
47 static int voltage_failsafe_off;
48 static int set_max_voltage;
49
50 #if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
51 static int ignore_acpi_limit;
52
53 static struct acpi_processor_performance *eps_acpi_cpu_perf;
54
55 /* Minimum necessary to get acpi_processor_get_bios_limit() working */
56 static int eps_acpi_init(void)
57 {
58         eps_acpi_cpu_perf = kzalloc(sizeof(*eps_acpi_cpu_perf),
59                                       GFP_KERNEL);
60         if (!eps_acpi_cpu_perf)
61                 return -ENOMEM;
62
63         if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
64                                                                 GFP_KERNEL)) {
65                 kfree(eps_acpi_cpu_perf);
66                 eps_acpi_cpu_perf = NULL;
67                 return -ENOMEM;
68         }
69
70         if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
71                 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
72                 kfree(eps_acpi_cpu_perf);
73                 eps_acpi_cpu_perf = NULL;
74                 return -EIO;
75         }
76         return 0;
77 }
78
79 static int eps_acpi_exit(struct cpufreq_policy *policy)
80 {
81         if (eps_acpi_cpu_perf) {
82                 acpi_processor_unregister_performance(0);
83                 free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
84                 kfree(eps_acpi_cpu_perf);
85                 eps_acpi_cpu_perf = NULL;
86         }
87         return 0;
88 }
89 #endif
90
91 static unsigned int eps_get(unsigned int cpu)
92 {
93         struct eps_cpu_data *centaur;
94         u32 lo, hi;
95
96         if (cpu)
97                 return 0;
98         centaur = eps_cpu[cpu];
99         if (centaur == NULL)
100                 return 0;
101
102         /* Return current frequency */
103         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
104         return centaur->fsb * ((lo >> 8) & 0xff);
105 }
106
107 static int eps_set_state(struct eps_cpu_data *centaur,
108                          struct cpufreq_policy *policy,
109                          u32 dest_state)
110 {
111         u32 lo, hi;
112         int i;
113
114         /* Wait while CPU is busy */
115         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
116         i = 0;
117         while (lo & ((1 << 16) | (1 << 17))) {
118                 udelay(16);
119                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
120                 i++;
121                 if (unlikely(i > 64)) {
122                         return -ENODEV;
123                 }
124         }
125         /* Set new multiplier and voltage */
126         wrmsr(MSR_IA32_PERF_CTL, dest_state & 0xffff, 0);
127         /* Wait until transition end */
128         i = 0;
129         do {
130                 udelay(16);
131                 rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
132                 i++;
133                 if (unlikely(i > 64)) {
134                         return -ENODEV;
135                 }
136         } while (lo & ((1 << 16) | (1 << 17)));
137
138 #ifdef DEBUG
139         {
140         u8 current_multiplier, current_voltage;
141
142         /* Print voltage and multiplier */
143         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
144         current_voltage = lo & 0xff;
145         pr_info("Current voltage = %dmV\n", current_voltage * 16 + 700);
146         current_multiplier = (lo >> 8) & 0xff;
147         pr_info("Current multiplier = %d\n", current_multiplier);
148         }
149 #endif
150         return 0;
151 }
152
153 static int eps_target(struct cpufreq_policy *policy, unsigned int index)
154 {
155         struct eps_cpu_data *centaur;
156         unsigned int cpu = policy->cpu;
157         unsigned int dest_state;
158         int ret;
159
160         if (unlikely(eps_cpu[cpu] == NULL))
161                 return -ENODEV;
162         centaur = eps_cpu[cpu];
163
164         /* Make frequency transition */
165         dest_state = centaur->freq_table[index].driver_data & 0xffff;
166         ret = eps_set_state(centaur, policy, dest_state);
167         if (ret)
168                 pr_err("Timeout!\n");
169         return ret;
170 }
171
172 static int eps_cpu_init(struct cpufreq_policy *policy)
173 {
174         unsigned int i;
175         u32 lo, hi;
176         u64 val;
177         u8 current_multiplier, current_voltage;
178         u8 max_multiplier, max_voltage;
179         u8 min_multiplier, min_voltage;
180         u8 brand = 0;
181         u32 fsb;
182         struct eps_cpu_data *centaur;
183         struct cpuinfo_x86 *c = &cpu_data(0);
184         struct cpufreq_frequency_table *f_table;
185         int k, step, voltage;
186         int states;
187 #if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
188         unsigned int limit;
189 #endif
190
191         if (policy->cpu != 0)
192                 return -ENODEV;
193
194         /* Check brand */
195         pr_info("Detected VIA ");
196
197         switch (c->x86_model) {
198         case 10:
199                 rdmsr(0x1153, lo, hi);
200                 brand = (((lo >> 2) ^ lo) >> 18) & 3;
201                 pr_cont("Model A ");
202                 break;
203         case 13:
204                 rdmsr(0x1154, lo, hi);
205                 brand = (((lo >> 4) ^ (lo >> 2))) & 0x000000ff;
206                 pr_cont("Model D ");
207                 break;
208         }
209
210         switch (brand) {
211         case EPS_BRAND_C7M:
212                 pr_cont("C7-M\n");
213                 break;
214         case EPS_BRAND_C7:
215                 pr_cont("C7\n");
216                 break;
217         case EPS_BRAND_EDEN:
218                 pr_cont("Eden\n");
219                 break;
220         case EPS_BRAND_C7D:
221                 pr_cont("C7-D\n");
222                 break;
223         case EPS_BRAND_C3:
224                 pr_cont("C3\n");
225                 return -ENODEV;
226                 break;
227         }
228         /* Enable Enhanced PowerSaver */
229         rdmsrl(MSR_IA32_MISC_ENABLE, val);
230         if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
231                 val |= MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP;
232                 wrmsrl(MSR_IA32_MISC_ENABLE, val);
233                 /* Can be locked at 0 */
234                 rdmsrl(MSR_IA32_MISC_ENABLE, val);
235                 if (!(val & MSR_IA32_MISC_ENABLE_ENHANCED_SPEEDSTEP)) {
236                         pr_info("Can't enable Enhanced PowerSaver\n");
237                         return -ENODEV;
238                 }
239         }
240
241         /* Print voltage and multiplier */
242         rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
243         current_voltage = lo & 0xff;
244         pr_info("Current voltage = %dmV\n", current_voltage * 16 + 700);
245         current_multiplier = (lo >> 8) & 0xff;
246         pr_info("Current multiplier = %d\n", current_multiplier);
247
248         /* Print limits */
249         max_voltage = hi & 0xff;
250         pr_info("Highest voltage = %dmV\n", max_voltage * 16 + 700);
251         max_multiplier = (hi >> 8) & 0xff;
252         pr_info("Highest multiplier = %d\n", max_multiplier);
253         min_voltage = (hi >> 16) & 0xff;
254         pr_info("Lowest voltage = %dmV\n", min_voltage * 16 + 700);
255         min_multiplier = (hi >> 24) & 0xff;
256         pr_info("Lowest multiplier = %d\n", min_multiplier);
257
258         /* Sanity checks */
259         if (current_multiplier == 0 || max_multiplier == 0
260             || min_multiplier == 0)
261                 return -EINVAL;
262         if (current_multiplier > max_multiplier
263             || max_multiplier <= min_multiplier)
264                 return -EINVAL;
265         if (current_voltage > 0x1f || max_voltage > 0x1f)
266                 return -EINVAL;
267         if (max_voltage < min_voltage
268             || current_voltage < min_voltage
269             || current_voltage > max_voltage)
270                 return -EINVAL;
271
272         /* Check for systems using underclocked CPU */
273         if (!freq_failsafe_off && max_multiplier != current_multiplier) {
274                 pr_info("Your processor is running at different frequency then its maximum. Aborting.\n");
275                 pr_info("You can use freq_failsafe_off option to disable this check.\n");
276                 return -EINVAL;
277         }
278         if (!voltage_failsafe_off && max_voltage != current_voltage) {
279                 pr_info("Your processor is running at different voltage then its maximum. Aborting.\n");
280                 pr_info("You can use voltage_failsafe_off option to disable this check.\n");
281                 return -EINVAL;
282         }
283
284         /* Calc FSB speed */
285         fsb = cpu_khz / current_multiplier;
286
287 #if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
288         /* Check for ACPI processor speed limit */
289         if (!ignore_acpi_limit && !eps_acpi_init()) {
290                 if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
291                         pr_info("ACPI limit %u.%uGHz\n",
292                                 limit/1000000,
293                                 (limit%1000000)/10000);
294                         eps_acpi_exit(policy);
295                         /* Check if max_multiplier is in BIOS limits */
296                         if (limit && max_multiplier * fsb > limit) {
297                                 pr_info("Aborting\n");
298                                 return -EINVAL;
299                         }
300                 }
301         }
302 #endif
303
304         /* Allow user to set lower maximum voltage then that reported
305          * by processor */
306         if (brand == EPS_BRAND_C7M && set_max_voltage) {
307                 u32 v;
308
309                 /* Change mV to something hardware can use */
310                 v = (set_max_voltage - 700) / 16;
311                 /* Check if voltage is within limits */
312                 if (v >= min_voltage && v <= max_voltage) {
313                         pr_info("Setting %dmV as maximum\n", v * 16 + 700);
314                         max_voltage = v;
315                 }
316         }
317
318         /* Calc number of p-states supported */
319         if (brand == EPS_BRAND_C7M)
320                 states = max_multiplier - min_multiplier + 1;
321         else
322                 states = 2;
323
324         /* Allocate private data and frequency table for current cpu */
325         centaur = kzalloc(struct_size(centaur, freq_table, states + 1),
326                           GFP_KERNEL);
327         if (!centaur)
328                 return -ENOMEM;
329         eps_cpu[0] = centaur;
330
331         /* Copy basic values */
332         centaur->fsb = fsb;
333 #if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
334         centaur->bios_limit = limit;
335 #endif
336
337         /* Fill frequency and MSR value table */
338         f_table = &centaur->freq_table[0];
339         if (brand != EPS_BRAND_C7M) {
340                 f_table[0].frequency = fsb * min_multiplier;
341                 f_table[0].driver_data = (min_multiplier << 8) | min_voltage;
342                 f_table[1].frequency = fsb * max_multiplier;
343                 f_table[1].driver_data = (max_multiplier << 8) | max_voltage;
344                 f_table[2].frequency = CPUFREQ_TABLE_END;
345         } else {
346                 k = 0;
347                 step = ((max_voltage - min_voltage) * 256)
348                         / (max_multiplier - min_multiplier);
349                 for (i = min_multiplier; i <= max_multiplier; i++) {
350                         voltage = (k * step) / 256 + min_voltage;
351                         f_table[k].frequency = fsb * i;
352                         f_table[k].driver_data = (i << 8) | voltage;
353                         k++;
354                 }
355                 f_table[k].frequency = CPUFREQ_TABLE_END;
356         }
357
358         policy->cpuinfo.transition_latency = 140000; /* 844mV -> 700mV in ns */
359         policy->freq_table = &centaur->freq_table[0];
360
361         return 0;
362 }
363
364 static int eps_cpu_exit(struct cpufreq_policy *policy)
365 {
366         unsigned int cpu = policy->cpu;
367
368         /* Bye */
369         kfree(eps_cpu[cpu]);
370         eps_cpu[cpu] = NULL;
371         return 0;
372 }
373
374 static struct cpufreq_driver eps_driver = {
375         .verify         = cpufreq_generic_frequency_table_verify,
376         .target_index   = eps_target,
377         .init           = eps_cpu_init,
378         .exit           = eps_cpu_exit,
379         .get            = eps_get,
380         .name           = "e_powersaver",
381         .attr           = cpufreq_generic_attr,
382 };
383
384
385 /* This driver will work only on Centaur C7 processors with
386  * Enhanced SpeedStep/PowerSaver registers */
387 static const struct x86_cpu_id eps_cpu_id[] = {
388         { X86_VENDOR_CENTAUR, 6, X86_MODEL_ANY, X86_FEATURE_EST },
389         {}
390 };
391 MODULE_DEVICE_TABLE(x86cpu, eps_cpu_id);
392
393 static int __init eps_init(void)
394 {
395         if (!x86_match_cpu(eps_cpu_id) || boot_cpu_data.x86_model < 10)
396                 return -ENODEV;
397         if (cpufreq_register_driver(&eps_driver))
398                 return -EINVAL;
399         return 0;
400 }
401
402 static void __exit eps_exit(void)
403 {
404         cpufreq_unregister_driver(&eps_driver);
405 }
406
407 /* Allow user to overclock his machine or to change frequency to higher after
408  * unloading module */
409 module_param(freq_failsafe_off, int, 0644);
410 MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
411 module_param(voltage_failsafe_off, int, 0644);
412 MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
413 #if IS_ENABLED(CONFIG_ACPI_PROCESSOR)
414 module_param(ignore_acpi_limit, int, 0644);
415 MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
416 #endif
417 module_param(set_max_voltage, int, 0644);
418 MODULE_PARM_DESC(set_max_voltage, "Set maximum CPU voltage (mV) C7-M only");
419
420 MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
421 MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");
422 MODULE_LICENSE("GPL");
423
424 module_init(eps_init);
425 module_exit(eps_exit);