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
52struct 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
62struct 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
75static struct cpufreq_driver pcc_cpufreq_driver;
76
77struct 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
93static void __iomem *pcch_virt_addr;
94static struct pcc_header __iomem *pcch_hdr;
95
96static DEFINE_SPINLOCK(pcc_lock);
97
98static struct acpi_generic_address doorbell;
99
100static u64 doorbell_preserve;
101static u64 doorbell_write;
102
103static u8 OSC_UUID[16] = {0x9F, 0x2C, 0x9B, 0x63, 0x91, 0x70, 0x1f, 0x49,
104			  0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46};
105
106struct pcc_cpu {
107	u32 input_offset;
108	u32 output_offset;
109};
110
111static struct pcc_cpu __percpu *pcc_cpu_info;
112
113static int pcc_cpufreq_verify(struct cpufreq_policy_data *policy)
114{
115	cpufreq_verify_within_cpu_limits(policy);
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	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
249static 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);
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_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;
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
559	pr_debug("init: policy->max is %d, policy->min is %d\n",
560		policy->max, policy->min);
561out:
562	return result;
563}
564
565static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
566{
567	return 0;
568}
569
570static 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
580static 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(&pcc_cpufreq_driver);
607
608	return ret;
609}
610
611static void pcc_cpufreq_remove(struct platform_device *pdev)
612{
613	cpufreq_unregister_driver(&pcc_cpufreq_driver);
614
615	pcc_clear_mapping();
616
617	free_percpu(pcc_cpu_info);
618}
619
620static struct platform_driver pcc_cpufreq_platdrv = {
621	.driver = {
622		.name	= "pcc-cpufreq",
623	},
624	.remove_new	= pcc_cpufreq_remove,
625};
626
627static int __init pcc_cpufreq_init(void)
628{
629	return platform_driver_probe(&pcc_cpufreq_platdrv, pcc_cpufreq_probe);
630}
631
632static void __exit pcc_cpufreq_exit(void)
633{
634	platform_driver_unregister(&pcc_cpufreq_platdrv);
635}
636
637MODULE_ALIAS("platform:pcc-cpufreq");
638
639MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
640MODULE_VERSION(PCC_VERSION);
641MODULE_DESCRIPTION("Processor Clocking Control interface driver");
642MODULE_LICENSE("GPL");
643
644late_initcall(pcc_cpufreq_init);
645module_exit(pcc_cpufreq_exit);
646