1 /*
2 * pcc-cpufreq.c - Processor Clocking Control firmware cpufreq interface
3 *
4 * Copyright (C) 2009 Red Hat, Matthew Garrett <mjg@redhat.com>
5 * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
6 * Nagananda Chumbalkar <nagananda.chumbalkar@hp.com>
7 *
8 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2 of the License.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or NON
17 * INFRINGEMENT. See the GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 675 Mass Ave, Cambridge, MA 02139, USA.
22 *
23 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
24 */
25
26 #include <linux/kernel.h>
27 #include <linux/module.h>
28 #include <linux/init.h>
29 #include <linux/smp.h>
30 #include <linux/sched.h>
31 #include <linux/cpufreq.h>
32 #include <linux/compiler.h>
33 #include <linux/slab.h>
34
35 #include <linux/acpi.h>
36 #include <linux/io.h>
37 #include <linux/spinlock.h>
38 #include <linux/uaccess.h>
39
40 #include <acpi/processor.h>
41
42 #define PCC_VERSION "1.10.00"
43 #define POLL_LOOPS 300
44
45 #define CMD_COMPLETE 0x1
46 #define CMD_GET_FREQ 0x0
47 #define CMD_SET_FREQ 0x1
48
49 #define BUF_SZ 4
50
51 struct pcc_register_resource {
52 u8 descriptor;
53 u16 length;
54 u8 space_id;
55 u8 bit_width;
56 u8 bit_offset;
57 u8 access_size;
58 u64 address;
59 } __attribute__ ((packed));
60
61 struct pcc_memory_resource {
62 u8 descriptor;
63 u16 length;
64 u8 space_id;
65 u8 resource_usage;
66 u8 type_specific;
67 u64 granularity;
68 u64 minimum;
69 u64 maximum;
70 u64 translation_offset;
71 u64 address_length;
72 } __attribute__ ((packed));
73
74 static struct cpufreq_driver pcc_cpufreq_driver;
75
76 struct pcc_header {
77 u32 signature;
78 u16 length;
79 u8 major;
80 u8 minor;
81 u32 features;
82 u16 command;
83 u16 status;
84 u32 latency;
85 u32 minimum_time;
86 u32 maximum_time;
87 u32 nominal;
88 u32 throttled_frequency;
89 u32 minimum_frequency;
90 };
91
92 static void __iomem *pcch_virt_addr;
93 static struct pcc_header __iomem *pcch_hdr;
94
95 static DEFINE_SPINLOCK(pcc_lock);
96
97 static struct acpi_generic_address doorbell;
98
99 static u64 doorbell_preserve;
100 static u64 doorbell_write;
101
102 static u8 OSC_UUID[16] = {0x9F, 0x2C, 0x9B, 0x63, 0x91, 0x70, 0x1f, 0x49,
103 0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46};
104
105 struct pcc_cpu {
106 u32 input_offset;
107 u32 output_offset;
108 };
109
110 static struct pcc_cpu __percpu *pcc_cpu_info;
111
pcc_cpufreq_verify(struct cpufreq_policy_data * policy)112 static int pcc_cpufreq_verify(struct cpufreq_policy_data *policy)
113 {
114 cpufreq_verify_within_cpu_limits(policy);
115 return 0;
116 }
117
pcc_cmd(void)118 static inline void pcc_cmd(void)
119 {
120 u64 doorbell_value;
121 int i;
122
123 acpi_read(&doorbell_value, &doorbell);
124 acpi_write((doorbell_value & doorbell_preserve) | doorbell_write,
125 &doorbell);
126
127 for (i = 0; i < POLL_LOOPS; i++) {
128 if (ioread16(&pcch_hdr->status) & CMD_COMPLETE)
129 break;
130 }
131 }
132
pcc_clear_mapping(void)133 static inline void pcc_clear_mapping(void)
134 {
135 if (pcch_virt_addr)
136 iounmap(pcch_virt_addr);
137 pcch_virt_addr = NULL;
138 }
139
pcc_get_freq(unsigned int cpu)140 static unsigned int pcc_get_freq(unsigned int cpu)
141 {
142 struct pcc_cpu *pcc_cpu_data;
143 unsigned int curr_freq;
144 unsigned int freq_limit;
145 u16 status;
146 u32 input_buffer;
147 u32 output_buffer;
148
149 spin_lock(&pcc_lock);
150
151 pr_debug("get: get_freq for CPU %d\n", cpu);
152 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
153
154 input_buffer = 0x1;
155 iowrite32(input_buffer,
156 (pcch_virt_addr + pcc_cpu_data->input_offset));
157 iowrite16(CMD_GET_FREQ, &pcch_hdr->command);
158
159 pcc_cmd();
160
161 output_buffer =
162 ioread32(pcch_virt_addr + pcc_cpu_data->output_offset);
163
164 /* Clear the input buffer - we are done with the current command */
165 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
166
167 status = ioread16(&pcch_hdr->status);
168 if (status != CMD_COMPLETE) {
169 pr_debug("get: FAILED: for CPU %d, status is %d\n",
170 cpu, status);
171 goto cmd_incomplete;
172 }
173 iowrite16(0, &pcch_hdr->status);
174 curr_freq = (((ioread32(&pcch_hdr->nominal) * (output_buffer & 0xff))
175 / 100) * 1000);
176
177 pr_debug("get: SUCCESS: (virtual) output_offset for cpu %d is "
178 "0x%p, contains a value of: 0x%x. Speed is: %d MHz\n",
179 cpu, (pcch_virt_addr + pcc_cpu_data->output_offset),
180 output_buffer, curr_freq);
181
182 freq_limit = (output_buffer >> 8) & 0xff;
183 if (freq_limit != 0xff) {
184 pr_debug("get: frequency for cpu %d is being temporarily"
185 " capped at %d\n", cpu, curr_freq);
186 }
187
188 spin_unlock(&pcc_lock);
189 return curr_freq;
190
191 cmd_incomplete:
192 iowrite16(0, &pcch_hdr->status);
193 spin_unlock(&pcc_lock);
194 return 0;
195 }
196
pcc_cpufreq_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)197 static int pcc_cpufreq_target(struct cpufreq_policy *policy,
198 unsigned int target_freq,
199 unsigned int relation)
200 {
201 struct pcc_cpu *pcc_cpu_data;
202 struct cpufreq_freqs freqs;
203 u16 status;
204 u32 input_buffer;
205 int cpu;
206
207 cpu = policy->cpu;
208 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
209
210 pr_debug("target: CPU %d should go to target freq: %d "
211 "(virtual) input_offset is 0x%p\n",
212 cpu, target_freq,
213 (pcch_virt_addr + pcc_cpu_data->input_offset));
214
215 freqs.old = policy->cur;
216 freqs.new = target_freq;
217 cpufreq_freq_transition_begin(policy, &freqs);
218 spin_lock(&pcc_lock);
219
220 input_buffer = 0x1 | (((target_freq * 100)
221 / (ioread32(&pcch_hdr->nominal) * 1000)) << 8);
222 iowrite32(input_buffer,
223 (pcch_virt_addr + pcc_cpu_data->input_offset));
224 iowrite16(CMD_SET_FREQ, &pcch_hdr->command);
225
226 pcc_cmd();
227
228 /* Clear the input buffer - we are done with the current command */
229 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
230
231 status = ioread16(&pcch_hdr->status);
232 iowrite16(0, &pcch_hdr->status);
233
234 cpufreq_freq_transition_end(policy, &freqs, status != CMD_COMPLETE);
235 spin_unlock(&pcc_lock);
236
237 if (status != CMD_COMPLETE) {
238 pr_debug("target: FAILED for cpu %d, with status: 0x%x\n",
239 cpu, status);
240 return -EINVAL;
241 }
242
243 pr_debug("target: was SUCCESSFUL for cpu %d\n", cpu);
244
245 return 0;
246 }
247
pcc_get_offset(int cpu)248 static int pcc_get_offset(int cpu)
249 {
250 acpi_status status;
251 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
252 union acpi_object *pccp, *offset;
253 struct pcc_cpu *pcc_cpu_data;
254 struct acpi_processor *pr;
255 int ret = 0;
256
257 pr = per_cpu(processors, cpu);
258 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
259
260 if (!pr)
261 return -ENODEV;
262
263 status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer);
264 if (ACPI_FAILURE(status))
265 return -ENODEV;
266
267 pccp = buffer.pointer;
268 if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) {
269 ret = -ENODEV;
270 goto out_free;
271 }
272
273 offset = &(pccp->package.elements[0]);
274 if (!offset || offset->type != ACPI_TYPE_INTEGER) {
275 ret = -ENODEV;
276 goto out_free;
277 }
278
279 pcc_cpu_data->input_offset = offset->integer.value;
280
281 offset = &(pccp->package.elements[1]);
282 if (!offset || offset->type != ACPI_TYPE_INTEGER) {
283 ret = -ENODEV;
284 goto out_free;
285 }
286
287 pcc_cpu_data->output_offset = offset->integer.value;
288
289 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
290 memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ);
291
292 pr_debug("pcc_get_offset: for CPU %d: pcc_cpu_data "
293 "input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n",
294 cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset);
295 out_free:
296 kfree(buffer.pointer);
297 return ret;
298 }
299
pcc_cpufreq_do_osc(acpi_handle * handle)300 static int __init pcc_cpufreq_do_osc(acpi_handle *handle)
301 {
302 acpi_status status;
303 struct acpi_object_list input;
304 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
305 union acpi_object in_params[4];
306 union acpi_object *out_obj;
307 u32 capabilities[2];
308 u32 errors;
309 u32 supported;
310 int ret = 0;
311
312 input.count = 4;
313 input.pointer = in_params;
314 in_params[0].type = ACPI_TYPE_BUFFER;
315 in_params[0].buffer.length = 16;
316 in_params[0].buffer.pointer = OSC_UUID;
317 in_params[1].type = ACPI_TYPE_INTEGER;
318 in_params[1].integer.value = 1;
319 in_params[2].type = ACPI_TYPE_INTEGER;
320 in_params[2].integer.value = 2;
321 in_params[3].type = ACPI_TYPE_BUFFER;
322 in_params[3].buffer.length = 8;
323 in_params[3].buffer.pointer = (u8 *)&capabilities;
324
325 capabilities[0] = OSC_QUERY_ENABLE;
326 capabilities[1] = 0x1;
327
328 status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
329 if (ACPI_FAILURE(status))
330 return -ENODEV;
331
332 if (!output.length)
333 return -ENODEV;
334
335 out_obj = output.pointer;
336 if (out_obj->type != ACPI_TYPE_BUFFER) {
337 ret = -ENODEV;
338 goto out_free;
339 }
340
341 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
342 if (errors) {
343 ret = -ENODEV;
344 goto out_free;
345 }
346
347 supported = *((u32 *)(out_obj->buffer.pointer + 4));
348 if (!(supported & 0x1)) {
349 ret = -ENODEV;
350 goto out_free;
351 }
352
353 kfree(output.pointer);
354 capabilities[0] = 0x0;
355 capabilities[1] = 0x1;
356
357 status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
358 if (ACPI_FAILURE(status))
359 return -ENODEV;
360
361 if (!output.length)
362 return -ENODEV;
363
364 out_obj = output.pointer;
365 if (out_obj->type != ACPI_TYPE_BUFFER) {
366 ret = -ENODEV;
367 goto out_free;
368 }
369
370 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
371 if (errors) {
372 ret = -ENODEV;
373 goto out_free;
374 }
375
376 supported = *((u32 *)(out_obj->buffer.pointer + 4));
377 if (!(supported & 0x1)) {
378 ret = -ENODEV;
379 goto out_free;
380 }
381
382 out_free:
383 kfree(output.pointer);
384 return ret;
385 }
386
pcc_cpufreq_probe(void)387 static int __init pcc_cpufreq_probe(void)
388 {
389 acpi_status status;
390 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
391 struct pcc_memory_resource *mem_resource;
392 struct pcc_register_resource *reg_resource;
393 union acpi_object *out_obj, *member;
394 acpi_handle handle, osc_handle;
395 int ret = 0;
396
397 status = acpi_get_handle(NULL, "\\_SB", &handle);
398 if (ACPI_FAILURE(status))
399 return -ENODEV;
400
401 if (!acpi_has_method(handle, "PCCH"))
402 return -ENODEV;
403
404 status = acpi_get_handle(handle, "_OSC", &osc_handle);
405 if (ACPI_SUCCESS(status)) {
406 ret = pcc_cpufreq_do_osc(&osc_handle);
407 if (ret)
408 pr_debug("probe: _OSC evaluation did not succeed\n");
409 /* Firmware's use of _OSC is optional */
410 ret = 0;
411 }
412
413 status = acpi_evaluate_object(handle, "PCCH", NULL, &output);
414 if (ACPI_FAILURE(status))
415 return -ENODEV;
416
417 out_obj = output.pointer;
418 if (out_obj->type != ACPI_TYPE_PACKAGE) {
419 ret = -ENODEV;
420 goto out_free;
421 }
422
423 member = &out_obj->package.elements[0];
424 if (member->type != ACPI_TYPE_BUFFER) {
425 ret = -ENODEV;
426 goto out_free;
427 }
428
429 mem_resource = (struct pcc_memory_resource *)member->buffer.pointer;
430
431 pr_debug("probe: mem_resource descriptor: 0x%x,"
432 " length: %d, space_id: %d, resource_usage: %d,"
433 " type_specific: %d, granularity: 0x%llx,"
434 " minimum: 0x%llx, maximum: 0x%llx,"
435 " translation_offset: 0x%llx, address_length: 0x%llx\n",
436 mem_resource->descriptor, mem_resource->length,
437 mem_resource->space_id, mem_resource->resource_usage,
438 mem_resource->type_specific, mem_resource->granularity,
439 mem_resource->minimum, mem_resource->maximum,
440 mem_resource->translation_offset,
441 mem_resource->address_length);
442
443 if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
444 ret = -ENODEV;
445 goto out_free;
446 }
447
448 pcch_virt_addr = ioremap(mem_resource->minimum,
449 mem_resource->address_length);
450 if (pcch_virt_addr == NULL) {
451 pr_debug("probe: could not map shared mem region\n");
452 ret = -ENOMEM;
453 goto out_free;
454 }
455 pcch_hdr = pcch_virt_addr;
456
457 pr_debug("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr);
458 pr_debug("probe: PCCH header is at physical address: 0x%llx,"
459 " signature: 0x%x, length: %d bytes, major: %d, minor: %d,"
460 " supported features: 0x%x, command field: 0x%x,"
461 " status field: 0x%x, nominal latency: %d us\n",
462 mem_resource->minimum, ioread32(&pcch_hdr->signature),
463 ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major),
464 ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features),
465 ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status),
466 ioread32(&pcch_hdr->latency));
467
468 pr_debug("probe: min time between commands: %d us,"
469 " max time between commands: %d us,"
470 " nominal CPU frequency: %d MHz,"
471 " minimum CPU frequency: %d MHz,"
472 " minimum CPU frequency without throttling: %d MHz\n",
473 ioread32(&pcch_hdr->minimum_time),
474 ioread32(&pcch_hdr->maximum_time),
475 ioread32(&pcch_hdr->nominal),
476 ioread32(&pcch_hdr->throttled_frequency),
477 ioread32(&pcch_hdr->minimum_frequency));
478
479 member = &out_obj->package.elements[1];
480 if (member->type != ACPI_TYPE_BUFFER) {
481 ret = -ENODEV;
482 goto pcch_free;
483 }
484
485 reg_resource = (struct pcc_register_resource *)member->buffer.pointer;
486
487 doorbell.space_id = reg_resource->space_id;
488 doorbell.bit_width = reg_resource->bit_width;
489 doorbell.bit_offset = reg_resource->bit_offset;
490 doorbell.access_width = 4;
491 doorbell.address = reg_resource->address;
492
493 pr_debug("probe: doorbell: space_id is %d, bit_width is %d, "
494 "bit_offset is %d, access_width is %d, address is 0x%llx\n",
495 doorbell.space_id, doorbell.bit_width, doorbell.bit_offset,
496 doorbell.access_width, reg_resource->address);
497
498 member = &out_obj->package.elements[2];
499 if (member->type != ACPI_TYPE_INTEGER) {
500 ret = -ENODEV;
501 goto pcch_free;
502 }
503
504 doorbell_preserve = member->integer.value;
505
506 member = &out_obj->package.elements[3];
507 if (member->type != ACPI_TYPE_INTEGER) {
508 ret = -ENODEV;
509 goto pcch_free;
510 }
511
512 doorbell_write = member->integer.value;
513
514 pr_debug("probe: doorbell_preserve: 0x%llx,"
515 " doorbell_write: 0x%llx\n",
516 doorbell_preserve, doorbell_write);
517
518 pcc_cpu_info = alloc_percpu(struct pcc_cpu);
519 if (!pcc_cpu_info) {
520 ret = -ENOMEM;
521 goto pcch_free;
522 }
523
524 printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency"
525 " limits: %d MHz, %d MHz\n", PCC_VERSION,
526 ioread32(&pcch_hdr->minimum_frequency),
527 ioread32(&pcch_hdr->nominal));
528 kfree(output.pointer);
529 return ret;
530 pcch_free:
531 pcc_clear_mapping();
532 out_free:
533 kfree(output.pointer);
534 return ret;
535 }
536
pcc_cpufreq_cpu_init(struct cpufreq_policy * policy)537 static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy)
538 {
539 unsigned int cpu = policy->cpu;
540 unsigned int result = 0;
541
542 if (!pcch_virt_addr) {
543 result = -1;
544 goto out;
545 }
546
547 result = pcc_get_offset(cpu);
548 if (result) {
549 pr_debug("init: PCCP evaluation failed\n");
550 goto out;
551 }
552
553 policy->max = policy->cpuinfo.max_freq =
554 ioread32(&pcch_hdr->nominal) * 1000;
555 policy->min = policy->cpuinfo.min_freq =
556 ioread32(&pcch_hdr->minimum_frequency) * 1000;
557
558 pr_debug("init: policy->max is %d, policy->min is %d\n",
559 policy->max, policy->min);
560 out:
561 return result;
562 }
563
pcc_cpufreq_cpu_exit(struct cpufreq_policy * policy)564 static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
565 {
566 return 0;
567 }
568
569 static struct cpufreq_driver pcc_cpufreq_driver = {
570 .flags = CPUFREQ_CONST_LOOPS,
571 .get = pcc_get_freq,
572 .verify = pcc_cpufreq_verify,
573 .target = pcc_cpufreq_target,
574 .init = pcc_cpufreq_cpu_init,
575 .exit = pcc_cpufreq_cpu_exit,
576 .name = "pcc-cpufreq",
577 };
578
pcc_cpufreq_init(void)579 static int __init pcc_cpufreq_init(void)
580 {
581 int ret;
582
583 /* Skip initialization if another cpufreq driver is there. */
584 if (cpufreq_get_current_driver())
585 return -EEXIST;
586
587 if (acpi_disabled)
588 return -ENODEV;
589
590 ret = pcc_cpufreq_probe();
591 if (ret) {
592 pr_debug("pcc_cpufreq_init: PCCH evaluation failed\n");
593 return ret;
594 }
595
596 if (num_present_cpus() > 4) {
597 pcc_cpufreq_driver.flags |= CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING;
598 pr_err("%s: Too many CPUs, dynamic performance scaling disabled\n",
599 __func__);
600 pr_err("%s: Try to enable another scaling driver through BIOS settings\n",
601 __func__);
602 pr_err("%s: and complain to the system vendor\n", __func__);
603 }
604
605 ret = cpufreq_register_driver(&pcc_cpufreq_driver);
606
607 return ret;
608 }
609
pcc_cpufreq_exit(void)610 static void __exit pcc_cpufreq_exit(void)
611 {
612 cpufreq_unregister_driver(&pcc_cpufreq_driver);
613
614 pcc_clear_mapping();
615
616 free_percpu(pcc_cpu_info);
617 }
618
619 static const struct acpi_device_id __maybe_unused processor_device_ids[] = {
620 {ACPI_PROCESSOR_OBJECT_HID, },
621 {ACPI_PROCESSOR_DEVICE_HID, },
622 {},
623 };
624 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
625
626 MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
627 MODULE_VERSION(PCC_VERSION);
628 MODULE_DESCRIPTION("Processor Clocking Control interface driver");
629 MODULE_LICENSE("GPL");
630
631 late_initcall(pcc_cpufreq_init);
632 module_exit(pcc_cpufreq_exit);
633
