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 #include <linux/platform_device.h>
35
36 #include <linux/acpi.h>
37 #include <linux/io.h>
38 #include <linux/spinlock.h>
39 #include <linux/uaccess.h>
40
41 #include <acpi/processor.h>
42
43 #define PCC_VERSION "1.10.00"
44 #define POLL_LOOPS 300
45
46 #define CMD_COMPLETE 0x1
47 #define CMD_GET_FREQ 0x0
48 #define CMD_SET_FREQ 0x1
49
50 #define BUF_SZ 4
51
52 struct pcc_register_resource {
53 u8 descriptor;
54 u16 length;
55 u8 space_id;
56 u8 bit_width;
57 u8 bit_offset;
58 u8 access_size;
59 u64 address;
60 } __attribute__ ((packed));
61
62 struct pcc_memory_resource {
63 u8 descriptor;
64 u16 length;
65 u8 space_id;
66 u8 resource_usage;
67 u8 type_specific;
68 u64 granularity;
69 u64 minimum;
70 u64 maximum;
71 u64 translation_offset;
72 u64 address_length;
73 } __attribute__ ((packed));
74
75 static struct cpufreq_driver pcc_cpufreq_driver;
76
77 struct pcc_header {
78 u32 signature;
79 u16 length;
80 u8 major;
81 u8 minor;
82 u32 features;
83 u16 command;
84 u16 status;
85 u32 latency;
86 u32 minimum_time;
87 u32 maximum_time;
88 u32 nominal;
89 u32 throttled_frequency;
90 u32 minimum_frequency;
91 };
92
93 static void __iomem *pcch_virt_addr;
94 static struct pcc_header __iomem *pcch_hdr;
95
96 static DEFINE_SPINLOCK(pcc_lock);
97
98 static struct acpi_generic_address doorbell;
99
100 static u64 doorbell_preserve;
101 static u64 doorbell_write;
102
103 static u8 OSC_UUID[16] = {0x9F, 0x2C, 0x9B, 0x63, 0x91, 0x70, 0x1f, 0x49,
104 0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46};
105
106 struct pcc_cpu {
107 u32 input_offset;
108 u32 output_offset;
109 };
110
111 static struct pcc_cpu __percpu *pcc_cpu_info;
112
pcc_cpufreq_verify(struct cpufreq_policy_data * policy)113 static int pcc_cpufreq_verify(struct cpufreq_policy_data *policy)
114 {
115 cpufreq_verify_within_cpu_limits(policy);
116 return 0;
117 }
118
pcc_cmd(void)119 static 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
pcc_clear_mapping(void)134 static inline void pcc_clear_mapping(void)
135 {
136 if (pcch_virt_addr)
137 iounmap(pcch_virt_addr);
138 pcch_virt_addr = NULL;
139 }
140
pcc_get_freq(unsigned int cpu)141 static 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
192 cmd_incomplete:
193 iowrite16(0, &pcch_hdr->status);
194 spin_unlock(&pcc_lock);
195 return 0;
196 }
197
pcc_cpufreq_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)198 static 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 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 spin_lock(&pcc_lock);
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 iowrite16(0, &pcch_hdr->status);
234
235 spin_unlock(&pcc_lock);
236 cpufreq_freq_transition_end(policy, &freqs, status != CMD_COMPLETE);
237
238 if (status != CMD_COMPLETE) {
239 pr_debug("target: FAILED for cpu %d, with status: 0x%x\n",
240 cpu, status);
241 return -EINVAL;
242 }
243
244 pr_debug("target: was SUCCESSFUL for cpu %d\n", cpu);
245
246 return 0;
247 }
248
pcc_get_offset(int cpu)249 static int pcc_get_offset(int cpu)
250 {
251 acpi_status status;
252 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
253 union acpi_object *pccp, *offset;
254 struct pcc_cpu *pcc_cpu_data;
255 struct acpi_processor *pr;
256 int ret = 0;
257
258 pr = per_cpu(processors, cpu);
259 pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
260
261 if (!pr)
262 return -ENODEV;
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);
296 out_free:
297 kfree(buffer.pointer);
298 return ret;
299 }
300
pcc_cpufreq_do_osc(acpi_handle * handle)301 static 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
383 out_free:
384 kfree(output.pointer);
385 return ret;
386 }
387
pcc_cpufreq_evaluate(void)388 static int __init pcc_cpufreq_evaluate(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;
396 int ret = 0;
397
398 status = acpi_get_handle(NULL, "\\_SB", &handle);
399 if (ACPI_FAILURE(status))
400 return -ENODEV;
401
402 if (!acpi_has_method(handle, "PCCH"))
403 return -ENODEV;
404
405 status = acpi_get_handle(handle, "_OSC", &osc_handle);
406 if (ACPI_SUCCESS(status)) {
407 ret = pcc_cpufreq_do_osc(&osc_handle);
408 if (ret)
409 pr_debug("probe: _OSC evaluation did not succeed\n");
410 /* Firmware's use of _OSC is optional */
411 ret = 0;
412 }
413
414 status = acpi_evaluate_object(handle, "PCCH", NULL, &output);
415 if (ACPI_FAILURE(status))
416 return -ENODEV;
417
418 out_obj = output.pointer;
419 if (out_obj->type != ACPI_TYPE_PACKAGE) {
420 ret = -ENODEV;
421 goto out_free;
422 }
423
424 member = &out_obj->package.elements[0];
425 if (member->type != ACPI_TYPE_BUFFER) {
426 ret = -ENODEV;
427 goto out_free;
428 }
429
430 mem_resource = (struct pcc_memory_resource *)member->buffer.pointer;
431
432 pr_debug("probe: mem_resource descriptor: 0x%x,"
433 " length: %d, space_id: %d, resource_usage: %d,"
434 " type_specific: %d, granularity: 0x%llx,"
435 " minimum: 0x%llx, maximum: 0x%llx,"
436 " translation_offset: 0x%llx, address_length: 0x%llx\n",
437 mem_resource->descriptor, mem_resource->length,
438 mem_resource->space_id, mem_resource->resource_usage,
439 mem_resource->type_specific, mem_resource->granularity,
440 mem_resource->minimum, mem_resource->maximum,
441 mem_resource->translation_offset,
442 mem_resource->address_length);
443
444 if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
445 ret = -ENODEV;
446 goto out_free;
447 }
448
449 pcch_virt_addr = ioremap(mem_resource->minimum,
450 mem_resource->address_length);
451 if (pcch_virt_addr == NULL) {
452 pr_debug("probe: could not map shared mem region\n");
453 ret = -ENOMEM;
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 = 4;
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;
531 pcch_free:
532 pcc_clear_mapping();
533 out_free:
534 kfree(output.pointer);
535 return ret;
536 }
537
pcc_cpufreq_cpu_init(struct cpufreq_policy * policy)538 static 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
559 pr_debug("init: policy->max is %d, policy->min is %d\n",
560 policy->max, policy->min);
561 out:
562 return result;
563 }
564
565 static struct cpufreq_driver pcc_cpufreq_driver = {
566 .flags = CPUFREQ_CONST_LOOPS,
567 .get = pcc_get_freq,
568 .verify = pcc_cpufreq_verify,
569 .target = pcc_cpufreq_target,
570 .init = pcc_cpufreq_cpu_init,
571 .name = "pcc-cpufreq",
572 };
573
pcc_cpufreq_probe(struct platform_device * pdev)574 static int __init pcc_cpufreq_probe(struct platform_device *pdev)
575 {
576 int ret;
577
578 /* Skip initialization if another cpufreq driver is there. */
579 if (cpufreq_get_current_driver())
580 return -ENODEV;
581
582 if (acpi_disabled)
583 return -ENODEV;
584
585 ret = pcc_cpufreq_evaluate();
586 if (ret) {
587 pr_debug("pcc_cpufreq_probe: PCCH evaluation failed\n");
588 return ret;
589 }
590
591 if (num_present_cpus() > 4) {
592 pcc_cpufreq_driver.flags |= CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING;
593 pr_err("%s: Too many CPUs, dynamic performance scaling disabled\n",
594 __func__);
595 pr_err("%s: Try to enable another scaling driver through BIOS settings\n",
596 __func__);
597 pr_err("%s: and complain to the system vendor\n", __func__);
598 }
599
600 ret = cpufreq_register_driver(&pcc_cpufreq_driver);
601
602 return ret;
603 }
604
pcc_cpufreq_remove(struct platform_device * pdev)605 static void pcc_cpufreq_remove(struct platform_device *pdev)
606 {
607 cpufreq_unregister_driver(&pcc_cpufreq_driver);
608
609 pcc_clear_mapping();
610
611 free_percpu(pcc_cpu_info);
612 }
613
614 static struct platform_driver pcc_cpufreq_platdrv = {
615 .driver = {
616 .name = "pcc-cpufreq",
617 },
618 .remove_new = pcc_cpufreq_remove,
619 };
620
pcc_cpufreq_init(void)621 static int __init pcc_cpufreq_init(void)
622 {
623 return platform_driver_probe(&pcc_cpufreq_platdrv, pcc_cpufreq_probe);
624 }
625
pcc_cpufreq_exit(void)626 static void __exit pcc_cpufreq_exit(void)
627 {
628 platform_driver_unregister(&pcc_cpufreq_platdrv);
629 }
630
631 MODULE_ALIAS("platform:pcc-cpufreq");
632
633 MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
634 MODULE_VERSION(PCC_VERSION);
635 MODULE_DESCRIPTION("Processor Clocking Control interface driver");
636 MODULE_LICENSE("GPL");
637
638 late_initcall(pcc_cpufreq_init);
639 module_exit(pcc_cpufreq_exit);
640