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