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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
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 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
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
229 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
230
231 status = ioread16(&pcch_hdr->status);
232 if (status != CMD_COMPLETE) {
233 pr_debug("target: FAILED for cpu %d, with status: 0x%x\n",
234 cpu, status);
235 goto cmd_incomplete;
236 }
237 iowrite16(0, &pcch_hdr->status);
238
239 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
240 pr_debug("target: was SUCCESSFUL for cpu %d\n", cpu);
241 spin_unlock(&pcc_lock);
242
243 return 0;
244
245cmd_incomplete:
246 freqs.new = freqs.old;
247 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
248 iowrite16(0, &pcch_hdr->status);
249 spin_unlock(&pcc_lock);
250 return -EINVAL;
251}
252
253static int pcc_get_offset(int cpu)
254{
255 acpi_status status;
256 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
257 union acpi_object *pccp, *offset;
258 struct pcc_cpu *pcc_cpu_data;
259 struct acpi_processor *pr;
260 int ret = 0;
261
262 pr = per_cpu(processors, cpu);
263 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
264
265 if (!pr)
266 return -ENODEV;
267
268 status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer);
269 if (ACPI_FAILURE(status))
270 return -ENODEV;
271
272 pccp = buffer.pointer;
273 if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) {
274 ret = -ENODEV;
275 goto out_free;
276 };
277
278 offset = &(pccp->package.elements[0]);
279 if (!offset || offset->type != ACPI_TYPE_INTEGER) {
280 ret = -ENODEV;
281 goto out_free;
282 }
283
284 pcc_cpu_data->input_offset = offset->integer.value;
285
286 offset = &(pccp->package.elements[1]);
287 if (!offset || offset->type != ACPI_TYPE_INTEGER) {
288 ret = -ENODEV;
289 goto out_free;
290 }
291
292 pcc_cpu_data->output_offset = offset->integer.value;
293
294 memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
295 memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ);
296
297 pr_debug("pcc_get_offset: for CPU %d: pcc_cpu_data "
298 "input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n",
299 cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset);
300out_free:
301 kfree(buffer.pointer);
302 return ret;
303}
304
305static int __init pcc_cpufreq_do_osc(acpi_handle *handle)
306{
307 acpi_status status;
308 struct acpi_object_list input;
309 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
310 union acpi_object in_params[4];
311 union acpi_object *out_obj;
312 u32 capabilities[2];
313 u32 errors;
314 u32 supported;
315 int ret = 0;
316
317 input.count = 4;
318 input.pointer = in_params;
319 in_params[0].type = ACPI_TYPE_BUFFER;
320 in_params[0].buffer.length = 16;
321 in_params[0].buffer.pointer = OSC_UUID;
322 in_params[1].type = ACPI_TYPE_INTEGER;
323 in_params[1].integer.value = 1;
324 in_params[2].type = ACPI_TYPE_INTEGER;
325 in_params[2].integer.value = 2;
326 in_params[3].type = ACPI_TYPE_BUFFER;
327 in_params[3].buffer.length = 8;
328 in_params[3].buffer.pointer = (u8 *)&capabilities;
329
330 capabilities[0] = OSC_QUERY_ENABLE;
331 capabilities[1] = 0x1;
332
333 status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
334 if (ACPI_FAILURE(status))
335 return -ENODEV;
336
337 if (!output.length)
338 return -ENODEV;
339
340 out_obj = output.pointer;
341 if (out_obj->type != ACPI_TYPE_BUFFER) {
342 ret = -ENODEV;
343 goto out_free;
344 }
345
346 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
347 if (errors) {
348 ret = -ENODEV;
349 goto out_free;
350 }
351
352 supported = *((u32 *)(out_obj->buffer.pointer + 4));
353 if (!(supported & 0x1)) {
354 ret = -ENODEV;
355 goto out_free;
356 }
357
358 kfree(output.pointer);
359 capabilities[0] = 0x0;
360 capabilities[1] = 0x1;
361
362 status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
363 if (ACPI_FAILURE(status))
364 return -ENODEV;
365
366 if (!output.length)
367 return -ENODEV;
368
369 out_obj = output.pointer;
370 if (out_obj->type != ACPI_TYPE_BUFFER) {
371 ret = -ENODEV;
372 goto out_free;
373 }
374
375 errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
376 if (errors) {
377 ret = -ENODEV;
378 goto out_free;
379 }
380
381 supported = *((u32 *)(out_obj->buffer.pointer + 4));
382 if (!(supported & 0x1)) {
383 ret = -ENODEV;
384 goto out_free;
385 }
386
387out_free:
388 kfree(output.pointer);
389 return ret;
390}
391
392static int __init pcc_cpufreq_probe(void)
393{
394 acpi_status status;
395 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
396 struct pcc_memory_resource *mem_resource;
397 struct pcc_register_resource *reg_resource;
398 union acpi_object *out_obj, *member;
399 acpi_handle handle, osc_handle, pcch_handle;
400 int ret = 0;
401
402 status = acpi_get_handle(NULL, "\\_SB", &handle);
403 if (ACPI_FAILURE(status))
404 return -ENODEV;
405
406 status = acpi_get_handle(handle, "PCCH", &pcch_handle);
407 if (ACPI_FAILURE(status))
408 return -ENODEV;
409
410 status = acpi_get_handle(handle, "_OSC", &osc_handle);
411 if (ACPI_SUCCESS(status)) {
412 ret = pcc_cpufreq_do_osc(&osc_handle);
413 if (ret)
414 pr_debug("probe: _OSC evaluation did not succeed\n");
415
416 ret = 0;
417 }
418
419 status = acpi_evaluate_object(handle, "PCCH", NULL, &output);
420 if (ACPI_FAILURE(status))
421 return -ENODEV;
422
423 out_obj = output.pointer;
424 if (out_obj->type != ACPI_TYPE_PACKAGE) {
425 ret = -ENODEV;
426 goto out_free;
427 }
428
429 member = &out_obj->package.elements[0];
430 if (member->type != ACPI_TYPE_BUFFER) {
431 ret = -ENODEV;
432 goto out_free;
433 }
434
435 mem_resource = (struct pcc_memory_resource *)member->buffer.pointer;
436
437 pr_debug("probe: mem_resource descriptor: 0x%x,"
438 " length: %d, space_id: %d, resource_usage: %d,"
439 " type_specific: %d, granularity: 0x%llx,"
440 " minimum: 0x%llx, maximum: 0x%llx,"
441 " translation_offset: 0x%llx, address_length: 0x%llx\n",
442 mem_resource->descriptor, mem_resource->length,
443 mem_resource->space_id, mem_resource->resource_usage,
444 mem_resource->type_specific, mem_resource->granularity,
445 mem_resource->minimum, mem_resource->maximum,
446 mem_resource->translation_offset,
447 mem_resource->address_length);
448
449 if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
450 ret = -ENODEV;
451 goto out_free;
452 }
453
454 pcch_virt_addr = ioremap_nocache(mem_resource->minimum,
455 mem_resource->address_length);
456 if (pcch_virt_addr == NULL) {
457 pr_debug("probe: could not map shared mem region\n");
458 ret = -ENOMEM;
459 goto out_free;
460 }
461 pcch_hdr = pcch_virt_addr;
462
463 pr_debug("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr);
464 pr_debug("probe: PCCH header is at physical address: 0x%llx,"
465 " signature: 0x%x, length: %d bytes, major: %d, minor: %d,"
466 " supported features: 0x%x, command field: 0x%x,"
467 " status field: 0x%x, nominal latency: %d us\n",
468 mem_resource->minimum, ioread32(&pcch_hdr->signature),
469 ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major),
470 ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features),
471 ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status),
472 ioread32(&pcch_hdr->latency));
473
474 pr_debug("probe: min time between commands: %d us,"
475 " max time between commands: %d us,"
476 " nominal CPU frequency: %d MHz,"
477 " minimum CPU frequency: %d MHz,"
478 " minimum CPU frequency without throttling: %d MHz\n",
479 ioread32(&pcch_hdr->minimum_time),
480 ioread32(&pcch_hdr->maximum_time),
481 ioread32(&pcch_hdr->nominal),
482 ioread32(&pcch_hdr->throttled_frequency),
483 ioread32(&pcch_hdr->minimum_frequency));
484
485 member = &out_obj->package.elements[1];
486 if (member->type != ACPI_TYPE_BUFFER) {
487 ret = -ENODEV;
488 goto pcch_free;
489 }
490
491 reg_resource = (struct pcc_register_resource *)member->buffer.pointer;
492
493 doorbell.space_id = reg_resource->space_id;
494 doorbell.bit_width = reg_resource->bit_width;
495 doorbell.bit_offset = reg_resource->bit_offset;
496 doorbell.access_width = 64;
497 doorbell.address = reg_resource->address;
498
499 pr_debug("probe: doorbell: space_id is %d, bit_width is %d, "
500 "bit_offset is %d, access_width is %d, address is 0x%llx\n",
501 doorbell.space_id, doorbell.bit_width, doorbell.bit_offset,
502 doorbell.access_width, reg_resource->address);
503
504 member = &out_obj->package.elements[2];
505 if (member->type != ACPI_TYPE_INTEGER) {
506 ret = -ENODEV;
507 goto pcch_free;
508 }
509
510 doorbell_preserve = member->integer.value;
511
512 member = &out_obj->package.elements[3];
513 if (member->type != ACPI_TYPE_INTEGER) {
514 ret = -ENODEV;
515 goto pcch_free;
516 }
517
518 doorbell_write = member->integer.value;
519
520 pr_debug("probe: doorbell_preserve: 0x%llx,"
521 " doorbell_write: 0x%llx\n",
522 doorbell_preserve, doorbell_write);
523
524 pcc_cpu_info = alloc_percpu(struct pcc_cpu);
525 if (!pcc_cpu_info) {
526 ret = -ENOMEM;
527 goto pcch_free;
528 }
529
530 printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency"
531 " limits: %d MHz, %d MHz\n", PCC_VERSION,
532 ioread32(&pcch_hdr->minimum_frequency),
533 ioread32(&pcch_hdr->nominal));
534 kfree(output.pointer);
535 return ret;
536pcch_free:
537 pcc_clear_mapping();
538out_free:
539 kfree(output.pointer);
540 return ret;
541}
542
543static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy)
544{
545 unsigned int cpu = policy->cpu;
546 unsigned int result = 0;
547
548 if (!pcch_virt_addr) {
549 result = -1;
550 goto out;
551 }
552
553 result = pcc_get_offset(cpu);
554 if (result) {
555 pr_debug("init: PCCP evaluation failed\n");
556 goto out;
557 }
558
559 policy->max = policy->cpuinfo.max_freq =
560 ioread32(&pcch_hdr->nominal) * 1000;
561 policy->min = policy->cpuinfo.min_freq =
562 ioread32(&pcch_hdr->minimum_frequency) * 1000;
563 policy->cur = pcc_get_freq(cpu);
564
565 if (!policy->cur) {
566 pr_debug("init: Unable to get current CPU frequency\n");
567 result = -EINVAL;
568 goto out;
569 }
570
571 pr_debug("init: policy->max is %d, policy->min is %d\n",
572 policy->max, policy->min);
573out:
574 return result;
575}
576
577static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
578{
579 return 0;
580}
581
582static struct cpufreq_driver pcc_cpufreq_driver = {
583 .flags = CPUFREQ_CONST_LOOPS,
584 .get = pcc_get_freq,
585 .verify = pcc_cpufreq_verify,
586 .target = pcc_cpufreq_target,
587 .init = pcc_cpufreq_cpu_init,
588 .exit = pcc_cpufreq_cpu_exit,
589 .name = "pcc-cpufreq",
590 .owner = THIS_MODULE,
591};
592
593static int __init pcc_cpufreq_init(void)
594{
595 int ret;
596
597 if (acpi_disabled)
598 return 0;
599
600 ret = pcc_cpufreq_probe();
601 if (ret) {
602 pr_debug("pcc_cpufreq_init: PCCH evaluation failed\n");
603 return ret;
604 }
605
606 ret = cpufreq_register_driver(&pcc_cpufreq_driver);
607
608 return ret;
609}
610
611static void __exit pcc_cpufreq_exit(void)
612{
613 cpufreq_unregister_driver(&pcc_cpufreq_driver);
614
615 pcc_clear_mapping();
616
617 free_percpu(pcc_cpu_info);
618}
619
620MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
621MODULE_VERSION(PCC_VERSION);
622MODULE_DESCRIPTION("Processor Clocking Control interface driver");
623MODULE_LICENSE("GPL");
624
625late_initcall(pcc_cpufreq_init);
626module_exit(pcc_cpufreq_exit);
627
