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 { |
78 | u32 ; |
79 | u16 ; |
80 | u8 ; |
81 | u8 ; |
82 | u32 ; |
83 | u16 command; |
84 | u16 ; |
85 | u32 ; |
86 | u32 ; |
87 | u32 ; |
88 | u32 ; |
89 | u32 ; |
90 | u32 ; |
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 | |
113 | static int pcc_cpufreq_verify(struct cpufreq_policy_data *policy) |
114 | { |
115 | cpufreq_verify_within_cpu_limits(policy); |
116 | return 0; |
117 | } |
118 | |
119 | static inline void pcc_cmd(void) |
120 | { |
121 | u64 doorbell_value; |
122 | int i; |
123 | |
124 | acpi_read(value: &doorbell_value, reg: &doorbell); |
125 | acpi_write(value: (doorbell_value & doorbell_preserve) | doorbell_write, |
126 | reg: &doorbell); |
127 | |
128 | for (i = 0; i < POLL_LOOPS; i++) { |
129 | if (ioread16(&pcch_hdr->status) & CMD_COMPLETE) |
130 | break; |
131 | } |
132 | } |
133 | |
134 | static inline void pcc_clear_mapping(void) |
135 | { |
136 | if (pcch_virt_addr) |
137 | iounmap(addr: pcch_virt_addr); |
138 | pcch_virt_addr = NULL; |
139 | } |
140 | |
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(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(lock: &pcc_lock); |
190 | return curr_freq; |
191 | |
192 | cmd_incomplete: |
193 | iowrite16(0, &pcch_hdr->status); |
194 | spin_unlock(lock: &pcc_lock); |
195 | return 0; |
196 | } |
197 | |
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: &freqs); |
219 | spin_lock(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(lock: &pcc_lock); |
236 | cpufreq_freq_transition_end(policy, freqs: &freqs, transition_failed: 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 | |
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(object: pr->handle, pathname: "PCCP" , NULL, return_object_buffer: &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(objp: buffer.pointer); |
298 | return ret; |
299 | } |
300 | |
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(object: *handle, pathname: "_OSC" , parameter_objects: &input, return_object_buffer: &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(objp: output.pointer); |
355 | capabilities[0] = 0x0; |
356 | capabilities[1] = 0x1; |
357 | |
358 | status = acpi_evaluate_object(object: *handle, pathname: "_OSC" , parameter_objects: &input, return_object_buffer: &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(objp: output.pointer); |
385 | return ret; |
386 | } |
387 | |
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, pathname: "\\_SB" , ret_handle: &handle); |
399 | if (ACPI_FAILURE(status)) |
400 | return -ENODEV; |
401 | |
402 | if (!acpi_has_method(handle, name: "PCCH" )) |
403 | return -ENODEV; |
404 | |
405 | status = acpi_get_handle(parent: handle, pathname: "_OSC" , ret_handle: &osc_handle); |
406 | if (ACPI_SUCCESS(status)) { |
407 | ret = pcc_cpufreq_do_osc(handle: &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(object: handle, pathname: "PCCH" , NULL, return_object_buffer: &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(offset: mem_resource->minimum, |
450 | size: 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(objp: output.pointer); |
530 | return ret; |
531 | pcch_free: |
532 | pcc_clear_mapping(); |
533 | out_free: |
534 | kfree(objp: output.pointer); |
535 | return ret; |
536 | } |
537 | |
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 int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy) |
566 | { |
567 | return 0; |
568 | } |
569 | |
570 | static struct cpufreq_driver pcc_cpufreq_driver = { |
571 | .flags = CPUFREQ_CONST_LOOPS, |
572 | .get = pcc_get_freq, |
573 | .verify = pcc_cpufreq_verify, |
574 | .target = pcc_cpufreq_target, |
575 | .init = pcc_cpufreq_cpu_init, |
576 | .exit = pcc_cpufreq_cpu_exit, |
577 | .name = "pcc-cpufreq" , |
578 | }; |
579 | |
580 | static int __init pcc_cpufreq_probe(struct platform_device *pdev) |
581 | { |
582 | int ret; |
583 | |
584 | /* Skip initialization if another cpufreq driver is there. */ |
585 | if (cpufreq_get_current_driver()) |
586 | return -ENODEV; |
587 | |
588 | if (acpi_disabled) |
589 | return -ENODEV; |
590 | |
591 | ret = pcc_cpufreq_evaluate(); |
592 | if (ret) { |
593 | pr_debug("pcc_cpufreq_probe: PCCH evaluation failed\n" ); |
594 | return ret; |
595 | } |
596 | |
597 | if (num_present_cpus() > 4) { |
598 | pcc_cpufreq_driver.flags |= CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING; |
599 | pr_err("%s: Too many CPUs, dynamic performance scaling disabled\n" , |
600 | __func__); |
601 | pr_err("%s: Try to enable another scaling driver through BIOS settings\n" , |
602 | __func__); |
603 | pr_err("%s: and complain to the system vendor\n" , __func__); |
604 | } |
605 | |
606 | ret = cpufreq_register_driver(driver_data: &pcc_cpufreq_driver); |
607 | |
608 | return ret; |
609 | } |
610 | |
611 | static void pcc_cpufreq_remove(struct platform_device *pdev) |
612 | { |
613 | cpufreq_unregister_driver(driver_data: &pcc_cpufreq_driver); |
614 | |
615 | pcc_clear_mapping(); |
616 | |
617 | free_percpu(pdata: pcc_cpu_info); |
618 | } |
619 | |
620 | static struct platform_driver pcc_cpufreq_platdrv = { |
621 | .driver = { |
622 | .name = "pcc-cpufreq" , |
623 | }, |
624 | .remove_new = pcc_cpufreq_remove, |
625 | }; |
626 | |
627 | static int __init pcc_cpufreq_init(void) |
628 | { |
629 | return platform_driver_probe(&pcc_cpufreq_platdrv, pcc_cpufreq_probe); |
630 | } |
631 | |
632 | static void __exit pcc_cpufreq_exit(void) |
633 | { |
634 | platform_driver_unregister(&pcc_cpufreq_platdrv); |
635 | } |
636 | |
637 | MODULE_ALIAS("platform:pcc-cpufreq" ); |
638 | |
639 | MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar" ); |
640 | MODULE_VERSION(PCC_VERSION); |
641 | MODULE_DESCRIPTION("Processor Clocking Control interface driver" ); |
642 | MODULE_LICENSE("GPL" ); |
643 | |
644 | late_initcall(pcc_cpufreq_init); |
645 | module_exit(pcc_cpufreq_exit); |
646 | |