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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
51struct 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
61struct 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
74static struct cpufreq_driver pcc_cpufreq_driver;
75
76struct 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
92static void __iomem *pcch_virt_addr;
93static struct pcc_header __iomem *pcch_hdr;
94
95static DEFINE_SPINLOCK(pcc_lock);
96
97static struct acpi_generic_address doorbell;
98
99static u64 doorbell_preserve;
100static u64 doorbell_write;
101
102static u8 OSC_UUID[16] = {0x9F, 0x2C, 0x9B, 0x63, 0x91, 0x70, 0x1f, 0x49,
103 0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46};
104
105struct pcc_cpu {
106 u32 input_offset;
107 u32 output_offset;
108};
109
110static struct pcc_cpu __percpu *pcc_cpu_info;
111
112static int pcc_cpufreq_verify(struct cpufreq_policy *policy)
113{
114 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
115 policy->cpuinfo.max_freq);
116 return 0;
117}
118
119static inline void pcc_cmd(void)
120{
121 u64 doorbell_value;
122 int i;
123
124 acpi_read(&doorbell_value, &doorbell);
125 acpi_write((doorbell_value & doorbell_preserve) | doorbell_write,
126 &doorbell);
127
128 for (i = 0; i < POLL_LOOPS; i++) {
129 if (ioread16(&pcch_hdr->status) & CMD_COMPLETE)
130 break;
131 }
132}
133
134static inline void pcc_clear_mapping(void)
135{
136 if (pcch_virt_addr)
137 iounmap(pcch_virt_addr);
138 pcch_virt_addr = NULL;
139}
140
141static unsigned int pcc_get_freq(unsigned int cpu)
142{
143 struct pcc_cpu *pcc_cpu_data;
144 unsigned int curr_freq;
145 unsigned int freq_limit;
146 u16 status;
147 u32 input_buffer;
148 u32 output_buffer;
149
150 spin_lock(&pcc_lock);
151
152 pr_debug("get: get_freq for CPU %d\n", cpu);
153 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
154
155 input_buffer = 0x1;
156 iowrite32(input_buffer,
157 (pcch_virt_addr + pcc_cpu_data->input_offset));
158 iowrite16(CMD_GET_FREQ, &pcch_hdr->command);
159
160 pcc_cmd();
161
162 output_buffer =
163 ioread32(pcch_virt_addr + pcc_cpu_data->output_offset);
164
165 /* Clear the input buffer - we are done with the current command */
166 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
167
168 status = ioread16(&pcch_hdr->status);
169 if (status != CMD_COMPLETE) {
170 pr_debug("get: FAILED: for CPU %d, status is %d\n",
171 cpu, status);
172 goto cmd_incomplete;
173 }
174 iowrite16(0, &pcch_hdr->status);
175 curr_freq = (((ioread32(&pcch_hdr->nominal) * (output_buffer & 0xff))
176 / 100) * 1000);
177
178 pr_debug("get: SUCCESS: (virtual) output_offset for cpu %d is "
179 "0x%p, contains a value of: 0x%x. Speed is: %d MHz\n",
180 cpu, (pcch_virt_addr + pcc_cpu_data->output_offset),
181 output_buffer, curr_freq);
182
183 freq_limit = (output_buffer >> 8) & 0xff;
184 if (freq_limit != 0xff) {
185 pr_debug("get: frequency for cpu %d is being temporarily"
186 " capped at %d\n", cpu, curr_freq);
187 }
188
189 spin_unlock(&pcc_lock);
190 return curr_freq;
191
192cmd_incomplete:
193 iowrite16(0, &pcch_hdr->status);
194 spin_unlock(&pcc_lock);
195 return 0;
196}
197
198static int pcc_cpufreq_target(struct cpufreq_policy *policy,
199 unsigned int target_freq,
200 unsigned int relation)
201{
202 struct pcc_cpu *pcc_cpu_data;
203 struct cpufreq_freqs freqs;
204 u16 status;
205 u32 input_buffer;
206 int cpu;
207
208 spin_lock(&pcc_lock);
209 cpu = policy->cpu;
210 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
211
212 pr_debug("target: CPU %d should go to target freq: %d "
213 "(virtual) input_offset is 0x%p\n",
214 cpu, target_freq,
215 (pcch_virt_addr + pcc_cpu_data->input_offset));
216
217 freqs.new = target_freq;
218 freqs.cpu = cpu;
219 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
220
221 input_buffer = 0x1 | (((target_freq * 100)
222 / (ioread32(&pcch_hdr->nominal) * 1000)) << 8);
223 iowrite32(input_buffer,
224 (pcch_virt_addr + pcc_cpu_data->input_offset));
225 iowrite16(CMD_SET_FREQ, &pcch_hdr->command);
226
227 pcc_cmd();
228
229 /* Clear the input buffer - we are done with the current command */
230 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
231
232 status = ioread16(&pcch_hdr->status);
233 if (status != CMD_COMPLETE) {
234 pr_debug("target: FAILED for cpu %d, with status: 0x%x\n",
235 cpu, status);
236 goto cmd_incomplete;
237 }
238 iowrite16(0, &pcch_hdr->status);
239
240 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
241 pr_debug("target: was SUCCESSFUL for cpu %d\n", cpu);
242 spin_unlock(&pcc_lock);
243
244 return 0;
245
246cmd_incomplete:
247 iowrite16(0, &pcch_hdr->status);
248 spin_unlock(&pcc_lock);
249 return -EINVAL;
250}
251
252static int pcc_get_offset(int cpu)
253{
254 acpi_status status;
255 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
256 union acpi_object *pccp, *offset;
257 struct pcc_cpu *pcc_cpu_data;
258 struct acpi_processor *pr;
259 int ret = 0;
260
261 pr = per_cpu(processors, cpu);
262 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
263
264 if (!pr)
265 return -ENODEV;
266
267 status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer);
268 if (ACPI_FAILURE(status))
269 return -ENODEV;
270
271 pccp = buffer.pointer;
272 if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) {
273 ret = -ENODEV;
274 goto out_free;
275 };
276
277 offset = &(pccp->package.elements[0]);
278 if (!offset || offset->type != ACPI_TYPE_INTEGER) {
279 ret = -ENODEV;
280 goto out_free;
281 }
282
283 pcc_cpu_data->input_offset = offset->integer.value;
284
285 offset = &(pccp->package.elements[1]);
286 if (!offset || offset->type != ACPI_TYPE_INTEGER) {
287 ret = -ENODEV;
288 goto out_free;
289 }
290
291 pcc_cpu_data->output_offset = offset->integer.value;
292
293 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
294 memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ);
295
296 pr_debug("pcc_get_offset: for CPU %d: pcc_cpu_data "
297 "input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n",
298 cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset);
299out_free:
300 kfree(buffer.pointer);
301 return ret;
302}
303
304static int __init pcc_cpufreq_do_osc(acpi_handle *handle)
305{
306 acpi_status status;
307 struct acpi_object_list input;
308 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
309 union acpi_object in_params[4];
310 union acpi_object *out_obj;
311 u32 capabilities[2];
312 u32 errors;
313 u32 supported;
314 int ret = 0;
315
316 input.count = 4;
317 input.pointer = in_params;
318 in_params[0].type = ACPI_TYPE_BUFFER;
319 in_params[0].buffer.length = 16;
320 in_params[0].buffer.pointer = OSC_UUID;
321 in_params[1].type = ACPI_TYPE_INTEGER;
322 in_params[1].integer.value = 1;
323 in_params[2].type = ACPI_TYPE_INTEGER;
324 in_params[2].integer.value = 2;
325 in_params[3].type = ACPI_TYPE_BUFFER;
326 in_params[3].buffer.length = 8;
327 in_params[3].buffer.pointer = (u8 *)&capabilities;
328
329 capabilities[0] = OSC_QUERY_ENABLE;
330 capabilities[1] = 0x1;
331
332 status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
333 if (ACPI_FAILURE(status))
334 return -ENODEV;
335
336 if (!output.length)
337 return -ENODEV;
338
339 out_obj = output.pointer;
340 if (out_obj->type != ACPI_TYPE_BUFFER) {
341 ret = -ENODEV;
342 goto out_free;
343 }
344
345 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
346 if (errors) {
347 ret = -ENODEV;
348 goto out_free;
349 }
350
351 supported = *((u32 *)(out_obj->buffer.pointer + 4));
352 if (!(supported & 0x1)) {
353 ret = -ENODEV;
354 goto out_free;
355 }
356
357 kfree(output.pointer);
358 capabilities[0] = 0x0;
359 capabilities[1] = 0x1;
360
361 status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
362 if (ACPI_FAILURE(status))
363 return -ENODEV;
364
365 if (!output.length)
366 return -ENODEV;
367
368 out_obj = output.pointer;
369 if (out_obj->type != ACPI_TYPE_BUFFER) {
370 ret = -ENODEV;
371 goto out_free;
372 }
373
374 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
375 if (errors) {
376 ret = -ENODEV;
377 goto out_free;
378 }
379
380 supported = *((u32 *)(out_obj->buffer.pointer + 4));
381 if (!(supported & 0x1)) {
382 ret = -ENODEV;
383 goto out_free;
384 }
385
386out_free:
387 kfree(output.pointer);
388 return ret;
389}
390
391static int __init pcc_cpufreq_probe(void)
392{
393 acpi_status status;
394 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
395 struct pcc_memory_resource *mem_resource;
396 struct pcc_register_resource *reg_resource;
397 union acpi_object *out_obj, *member;
398 acpi_handle handle, osc_handle, pcch_handle;
399 int ret = 0;
400
401 status = acpi_get_handle(NULL, "\\_SB", &handle);
402 if (ACPI_FAILURE(status))
403 return -ENODEV;
404
405 status = acpi_get_handle(handle, "PCCH", &pcch_handle);
406 if (ACPI_FAILURE(status))
407 return -ENODEV;
408
409 status = acpi_get_handle(handle, "_OSC", &osc_handle);
410 if (ACPI_SUCCESS(status)) {
411 ret = pcc_cpufreq_do_osc(&osc_handle);
412 if (ret)
413 pr_debug("probe: _OSC evaluation did not succeed\n");
414 /* Firmware's use of _OSC is optional */
415 ret = 0;
416 }
417
418 status = acpi_evaluate_object(handle, "PCCH", NULL, &output);
419 if (ACPI_FAILURE(status))
420 return -ENODEV;
421
422 out_obj = output.pointer;
423 if (out_obj->type != ACPI_TYPE_PACKAGE) {
424 ret = -ENODEV;
425 goto out_free;
426 }
427
428 member = &out_obj->package.elements[0];
429 if (member->type != ACPI_TYPE_BUFFER) {
430 ret = -ENODEV;
431 goto out_free;
432 }
433
434 mem_resource = (struct pcc_memory_resource *)member->buffer.pointer;
435
436 pr_debug("probe: mem_resource descriptor: 0x%x,"
437 " length: %d, space_id: %d, resource_usage: %d,"
438 " type_specific: %d, granularity: 0x%llx,"
439 " minimum: 0x%llx, maximum: 0x%llx,"
440 " translation_offset: 0x%llx, address_length: 0x%llx\n",
441 mem_resource->descriptor, mem_resource->length,
442 mem_resource->space_id, mem_resource->resource_usage,
443 mem_resource->type_specific, mem_resource->granularity,
444 mem_resource->minimum, mem_resource->maximum,
445 mem_resource->translation_offset,
446 mem_resource->address_length);
447
448 if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
449 ret = -ENODEV;
450 goto out_free;
451 }
452
453 pcch_virt_addr = ioremap_nocache(mem_resource->minimum,
454 mem_resource->address_length);
455 if (pcch_virt_addr == NULL) {
456 pr_debug("probe: could not map shared mem region\n");
457 goto out_free;
458 }
459 pcch_hdr = pcch_virt_addr;
460
461 pr_debug("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr);
462 pr_debug("probe: PCCH header is at physical address: 0x%llx,"
463 " signature: 0x%x, length: %d bytes, major: %d, minor: %d,"
464 " supported features: 0x%x, command field: 0x%x,"
465 " status field: 0x%x, nominal latency: %d us\n",
466 mem_resource->minimum, ioread32(&pcch_hdr->signature),
467 ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major),
468 ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features),
469 ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status),
470 ioread32(&pcch_hdr->latency));
471
472 pr_debug("probe: min time between commands: %d us,"
473 " max time between commands: %d us,"
474 " nominal CPU frequency: %d MHz,"
475 " minimum CPU frequency: %d MHz,"
476 " minimum CPU frequency without throttling: %d MHz\n",
477 ioread32(&pcch_hdr->minimum_time),
478 ioread32(&pcch_hdr->maximum_time),
479 ioread32(&pcch_hdr->nominal),
480 ioread32(&pcch_hdr->throttled_frequency),
481 ioread32(&pcch_hdr->minimum_frequency));
482
483 member = &out_obj->package.elements[1];
484 if (member->type != ACPI_TYPE_BUFFER) {
485 ret = -ENODEV;
486 goto pcch_free;
487 }
488
489 reg_resource = (struct pcc_register_resource *)member->buffer.pointer;
490
491 doorbell.space_id = reg_resource->space_id;
492 doorbell.bit_width = reg_resource->bit_width;
493 doorbell.bit_offset = reg_resource->bit_offset;
494 doorbell.access_width = 64;
495 doorbell.address = reg_resource->address;
496
497 pr_debug("probe: doorbell: space_id is %d, bit_width is %d, "
498 "bit_offset is %d, access_width is %d, address is 0x%llx\n",
499 doorbell.space_id, doorbell.bit_width, doorbell.bit_offset,
500 doorbell.access_width, reg_resource->address);
501
502 member = &out_obj->package.elements[2];
503 if (member->type != ACPI_TYPE_INTEGER) {
504 ret = -ENODEV;
505 goto pcch_free;
506 }
507
508 doorbell_preserve = member->integer.value;
509
510 member = &out_obj->package.elements[3];
511 if (member->type != ACPI_TYPE_INTEGER) {
512 ret = -ENODEV;
513 goto pcch_free;
514 }
515
516 doorbell_write = member->integer.value;
517
518 pr_debug("probe: doorbell_preserve: 0x%llx,"
519 " doorbell_write: 0x%llx\n",
520 doorbell_preserve, doorbell_write);
521
522 pcc_cpu_info = alloc_percpu(struct pcc_cpu);
523 if (!pcc_cpu_info) {
524 ret = -ENOMEM;
525 goto pcch_free;
526 }
527
528 printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency"
529 " limits: %d MHz, %d MHz\n", PCC_VERSION,
530 ioread32(&pcch_hdr->minimum_frequency),
531 ioread32(&pcch_hdr->nominal));
532 kfree(output.pointer);
533 return ret;
534pcch_free:
535 pcc_clear_mapping();
536out_free:
537 kfree(output.pointer);
538 return ret;
539}
540
541static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy)
542{
543 unsigned int cpu = policy->cpu;
544 unsigned int result = 0;
545
546 if (!pcch_virt_addr) {
547 result = -1;
548 goto out;
549 }
550
551 result = pcc_get_offset(cpu);
552 if (result) {
553 pr_debug("init: PCCP evaluation failed\n");
554 goto out;
555 }
556
557 policy->max = policy->cpuinfo.max_freq =
558 ioread32(&pcch_hdr->nominal) * 1000;
559 policy->min = policy->cpuinfo.min_freq =
560 ioread32(&pcch_hdr->minimum_frequency) * 1000;
561 policy->cur = pcc_get_freq(cpu);
562
563 if (!policy->cur) {
564 pr_debug("init: Unable to get current CPU frequency\n");
565 result = -EINVAL;
566 goto out;
567 }
568
569 pr_debug("init: policy->max is %d, policy->min is %d\n",
570 policy->max, policy->min);
571out:
572 return result;
573}
574
575static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
576{
577 return 0;
578}
579
580static struct cpufreq_driver pcc_cpufreq_driver = {
581 .flags = CPUFREQ_CONST_LOOPS,
582 .get = pcc_get_freq,
583 .verify = pcc_cpufreq_verify,
584 .target = pcc_cpufreq_target,
585 .init = pcc_cpufreq_cpu_init,
586 .exit = pcc_cpufreq_cpu_exit,
587 .name = "pcc-cpufreq",
588 .owner = THIS_MODULE,
589};
590
591static int __init pcc_cpufreq_init(void)
592{
593 int ret;
594
595 if (acpi_disabled)
596 return 0;
597
598 ret = pcc_cpufreq_probe();
599 if (ret) {
600 pr_debug("pcc_cpufreq_init: PCCH evaluation failed\n");
601 return ret;
602 }
603
604 ret = cpufreq_register_driver(&pcc_cpufreq_driver);
605
606 return ret;
607}
608
609static void __exit pcc_cpufreq_exit(void)
610{
611 cpufreq_unregister_driver(&pcc_cpufreq_driver);
612
613 pcc_clear_mapping();
614
615 free_percpu(pcc_cpu_info);
616}
617
618MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
619MODULE_VERSION(PCC_VERSION);
620MODULE_DESCRIPTION("Processor Clocking Control interface driver");
621MODULE_LICENSE("GPL");
622
623late_initcall(pcc_cpufreq_init);
624module_exit(pcc_cpufreq_exit);
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
51struct 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
61struct 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
74static struct cpufreq_driver pcc_cpufreq_driver;
75
76struct 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
92static void __iomem *pcch_virt_addr;
93static struct pcc_header __iomem *pcch_hdr;
94
95static DEFINE_SPINLOCK(pcc_lock);
96
97static struct acpi_generic_address doorbell;
98
99static u64 doorbell_preserve;
100static u64 doorbell_write;
101
102static u8 OSC_UUID[16] = {0x9F, 0x2C, 0x9B, 0x63, 0x91, 0x70, 0x1f, 0x49,
103 0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46};
104
105struct pcc_cpu {
106 u32 input_offset;
107 u32 output_offset;
108};
109
110static struct pcc_cpu __percpu *pcc_cpu_info;
111
112static int pcc_cpufreq_verify(struct cpufreq_policy *policy)
113{
114 cpufreq_verify_within_cpu_limits(policy);
115 return 0;
116}
117
118static 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
133static inline void pcc_clear_mapping(void)
134{
135 if (pcch_virt_addr)
136 iounmap(pcch_virt_addr);
137 pcch_virt_addr = NULL;
138}
139
140static 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
191cmd_incomplete:
192 iowrite16(0, &pcch_hdr->status);
193 spin_unlock(&pcc_lock);
194 return 0;
195}
196
197static 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 spin_lock(&pcc_lock);
208 cpu = policy->cpu;
209 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
210
211 pr_debug("target: CPU %d should go to target freq: %d "
212 "(virtual) input_offset is 0x%p\n",
213 cpu, target_freq,
214 (pcch_virt_addr + pcc_cpu_data->input_offset));
215
216 freqs.old = policy->cur;
217 freqs.new = target_freq;
218 cpufreq_freq_transition_begin(policy, &freqs);
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
248static 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);
295out_free:
296 kfree(buffer.pointer);
297 return ret;
298}
299
300static 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
382out_free:
383 kfree(output.pointer);
384 return ret;
385}
386
387static 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_nocache(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 = 64;
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;
530pcch_free:
531 pcc_clear_mapping();
532out_free:
533 kfree(output.pointer);
534 return ret;
535}
536
537static 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);
560out:
561 return result;
562}
563
564static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
565{
566 return 0;
567}
568
569static 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
579static int __init pcc_cpufreq_init(void)
580{
581 int ret;
582
583 if (acpi_disabled)
584 return 0;
585
586 ret = pcc_cpufreq_probe();
587 if (ret) {
588 pr_debug("pcc_cpufreq_init: PCCH evaluation failed\n");
589 return ret;
590 }
591
592 ret = cpufreq_register_driver(&pcc_cpufreq_driver);
593
594 return ret;
595}
596
597static void __exit pcc_cpufreq_exit(void)
598{
599 cpufreq_unregister_driver(&pcc_cpufreq_driver);
600
601 pcc_clear_mapping();
602
603 free_percpu(pcc_cpu_info);
604}
605
606MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
607MODULE_VERSION(PCC_VERSION);
608MODULE_DESCRIPTION("Processor Clocking Control interface driver");
609MODULE_LICENSE("GPL");
610
611late_initcall(pcc_cpufreq_init);
612module_exit(pcc_cpufreq_exit);