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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * CPPC (Collaborative Processor Performance Control) methods used by CPUfreq drivers.
4 *
5 * (C) Copyright 2014, 2015 Linaro Ltd.
6 * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
7 *
8 * CPPC describes a few methods for controlling CPU performance using
9 * information from a per CPU table called CPC. This table is described in
10 * the ACPI v5.0+ specification. The table consists of a list of
11 * registers which may be memory mapped or hardware registers and also may
12 * include some static integer values.
13 *
14 * CPU performance is on an abstract continuous scale as against a discretized
15 * P-state scale which is tied to CPU frequency only. In brief, the basic
16 * operation involves:
17 *
18 * - OS makes a CPU performance request. (Can provide min and max bounds)
19 *
20 * - Platform (such as BMC) is free to optimize request within requested bounds
21 * depending on power/thermal budgets etc.
22 *
23 * - Platform conveys its decision back to OS
24 *
25 * The communication between OS and platform occurs through another medium
26 * called (PCC) Platform Communication Channel. This is a generic mailbox like
27 * mechanism which includes doorbell semantics to indicate register updates.
28 * See drivers/mailbox/pcc.c for details on PCC.
29 *
30 * Finer details about the PCC and CPPC spec are available in the ACPI v5.1 and
31 * above specifications.
32 */
33
34#define pr_fmt(fmt) "ACPI CPPC: " fmt
35
36#include <linux/delay.h>
37#include <linux/iopoll.h>
38#include <linux/ktime.h>
39#include <linux/rwsem.h>
40#include <linux/wait.h>
41#include <linux/topology.h>
42
43#include <acpi/cppc_acpi.h>
44
45struct cppc_pcc_data {
46 struct mbox_chan *pcc_channel;
47 void __iomem *pcc_comm_addr;
48 bool pcc_channel_acquired;
49 unsigned int deadline_us;
50 unsigned int pcc_mpar, pcc_mrtt, pcc_nominal;
51
52 bool pending_pcc_write_cmd; /* Any pending/batched PCC write cmds? */
53 bool platform_owns_pcc; /* Ownership of PCC subspace */
54 unsigned int pcc_write_cnt; /* Running count of PCC write commands */
55
56 /*
57 * Lock to provide controlled access to the PCC channel.
58 *
59 * For performance critical usecases(currently cppc_set_perf)
60 * We need to take read_lock and check if channel belongs to OSPM
61 * before reading or writing to PCC subspace
62 * We need to take write_lock before transferring the channel
63 * ownership to the platform via a Doorbell
64 * This allows us to batch a number of CPPC requests if they happen
65 * to originate in about the same time
66 *
67 * For non-performance critical usecases(init)
68 * Take write_lock for all purposes which gives exclusive access
69 */
70 struct rw_semaphore pcc_lock;
71
72 /* Wait queue for CPUs whose requests were batched */
73 wait_queue_head_t pcc_write_wait_q;
74 ktime_t last_cmd_cmpl_time;
75 ktime_t last_mpar_reset;
76 int mpar_count;
77 int refcount;
78};
79
80/* Array to represent the PCC channel per subspace ID */
81static struct cppc_pcc_data *pcc_data[MAX_PCC_SUBSPACES];
82/* The cpu_pcc_subspace_idx contains per CPU subspace ID */
83static DEFINE_PER_CPU(int, cpu_pcc_subspace_idx);
84
85/*
86 * The cpc_desc structure contains the ACPI register details
87 * as described in the per CPU _CPC tables. The details
88 * include the type of register (e.g. PCC, System IO, FFH etc.)
89 * and destination addresses which lets us READ/WRITE CPU performance
90 * information using the appropriate I/O methods.
91 */
92static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
93
94/* pcc mapped address + header size + offset within PCC subspace */
95#define GET_PCC_VADDR(offs, pcc_ss_id) (pcc_data[pcc_ss_id]->pcc_comm_addr + \
96 0x8 + (offs))
97
98/* Check if a CPC register is in PCC */
99#define CPC_IN_PCC(cpc) ((cpc)->type == ACPI_TYPE_BUFFER && \
100 (cpc)->cpc_entry.reg.space_id == \
101 ACPI_ADR_SPACE_PLATFORM_COMM)
102
103/* Evaluates to True if reg is a NULL register descriptor */
104#define IS_NULL_REG(reg) ((reg)->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY && \
105 (reg)->address == 0 && \
106 (reg)->bit_width == 0 && \
107 (reg)->bit_offset == 0 && \
108 (reg)->access_width == 0)
109
110/* Evaluates to True if an optional cpc field is supported */
111#define CPC_SUPPORTED(cpc) ((cpc)->type == ACPI_TYPE_INTEGER ? \
112 !!(cpc)->cpc_entry.int_value : \
113 !IS_NULL_REG(&(cpc)->cpc_entry.reg))
114/*
115 * Arbitrary Retries in case the remote processor is slow to respond
116 * to PCC commands. Keeping it high enough to cover emulators where
117 * the processors run painfully slow.
118 */
119#define NUM_RETRIES 500ULL
120
121#define define_one_cppc_ro(_name) \
122static struct kobj_attribute _name = \
123__ATTR(_name, 0444, show_##_name, NULL)
124
125#define to_cpc_desc(a) container_of(a, struct cpc_desc, kobj)
126
127#define show_cppc_data(access_fn, struct_name, member_name) \
128 static ssize_t show_##member_name(struct kobject *kobj, \
129 struct kobj_attribute *attr, char *buf) \
130 { \
131 struct cpc_desc *cpc_ptr = to_cpc_desc(kobj); \
132 struct struct_name st_name = {0}; \
133 int ret; \
134 \
135 ret = access_fn(cpc_ptr->cpu_id, &st_name); \
136 if (ret) \
137 return ret; \
138 \
139 return scnprintf(buf, PAGE_SIZE, "%llu\n", \
140 (u64)st_name.member_name); \
141 } \
142 define_one_cppc_ro(member_name)
143
144show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, highest_perf);
145show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_perf);
146show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_perf);
147show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_nonlinear_perf);
148show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_freq);
149show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq);
150
151show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf);
152show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time);
153
154static ssize_t show_feedback_ctrs(struct kobject *kobj,
155 struct kobj_attribute *attr, char *buf)
156{
157 struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);
158 struct cppc_perf_fb_ctrs fb_ctrs = {0};
159 int ret;
160
161 ret = cppc_get_perf_ctrs(cpc_ptr->cpu_id, &fb_ctrs);
162 if (ret)
163 return ret;
164
165 return scnprintf(buf, PAGE_SIZE, "ref:%llu del:%llu\n",
166 fb_ctrs.reference, fb_ctrs.delivered);
167}
168define_one_cppc_ro(feedback_ctrs);
169
170static struct attribute *cppc_attrs[] = {
171 &feedback_ctrs.attr,
172 &reference_perf.attr,
173 &wraparound_time.attr,
174 &highest_perf.attr,
175 &lowest_perf.attr,
176 &lowest_nonlinear_perf.attr,
177 &nominal_perf.attr,
178 &nominal_freq.attr,
179 &lowest_freq.attr,
180 NULL
181};
182
183static struct kobj_type cppc_ktype = {
184 .sysfs_ops = &kobj_sysfs_ops,
185 .default_attrs = cppc_attrs,
186};
187
188static int check_pcc_chan(int pcc_ss_id, bool chk_err_bit)
189{
190 int ret, status;
191 struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
192 struct acpi_pcct_shared_memory __iomem *generic_comm_base =
193 pcc_ss_data->pcc_comm_addr;
194
195 if (!pcc_ss_data->platform_owns_pcc)
196 return 0;
197
198 /*
199 * Poll PCC status register every 3us(delay_us) for maximum of
200 * deadline_us(timeout_us) until PCC command complete bit is set(cond)
201 */
202 ret = readw_relaxed_poll_timeout(&generic_comm_base->status, status,
203 status & PCC_CMD_COMPLETE_MASK, 3,
204 pcc_ss_data->deadline_us);
205
206 if (likely(!ret)) {
207 pcc_ss_data->platform_owns_pcc = false;
208 if (chk_err_bit && (status & PCC_ERROR_MASK))
209 ret = -EIO;
210 }
211
212 if (unlikely(ret))
213 pr_err("PCC check channel failed for ss: %d. ret=%d\n",
214 pcc_ss_id, ret);
215
216 return ret;
217}
218
219/*
220 * This function transfers the ownership of the PCC to the platform
221 * So it must be called while holding write_lock(pcc_lock)
222 */
223static int send_pcc_cmd(int pcc_ss_id, u16 cmd)
224{
225 int ret = -EIO, i;
226 struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
227 struct acpi_pcct_shared_memory __iomem *generic_comm_base =
228 pcc_ss_data->pcc_comm_addr;
229 unsigned int time_delta;
230
231 /*
232 * For CMD_WRITE we know for a fact the caller should have checked
233 * the channel before writing to PCC space
234 */
235 if (cmd == CMD_READ) {
236 /*
237 * If there are pending cpc_writes, then we stole the channel
238 * before write completion, so first send a WRITE command to
239 * platform
240 */
241 if (pcc_ss_data->pending_pcc_write_cmd)
242 send_pcc_cmd(pcc_ss_id, CMD_WRITE);
243
244 ret = check_pcc_chan(pcc_ss_id, false);
245 if (ret)
246 goto end;
247 } else /* CMD_WRITE */
248 pcc_ss_data->pending_pcc_write_cmd = FALSE;
249
250 /*
251 * Handle the Minimum Request Turnaround Time(MRTT)
252 * "The minimum amount of time that OSPM must wait after the completion
253 * of a command before issuing the next command, in microseconds"
254 */
255 if (pcc_ss_data->pcc_mrtt) {
256 time_delta = ktime_us_delta(ktime_get(),
257 pcc_ss_data->last_cmd_cmpl_time);
258 if (pcc_ss_data->pcc_mrtt > time_delta)
259 udelay(pcc_ss_data->pcc_mrtt - time_delta);
260 }
261
262 /*
263 * Handle the non-zero Maximum Periodic Access Rate(MPAR)
264 * "The maximum number of periodic requests that the subspace channel can
265 * support, reported in commands per minute. 0 indicates no limitation."
266 *
267 * This parameter should be ideally zero or large enough so that it can
268 * handle maximum number of requests that all the cores in the system can
269 * collectively generate. If it is not, we will follow the spec and just
270 * not send the request to the platform after hitting the MPAR limit in
271 * any 60s window
272 */
273 if (pcc_ss_data->pcc_mpar) {
274 if (pcc_ss_data->mpar_count == 0) {
275 time_delta = ktime_ms_delta(ktime_get(),
276 pcc_ss_data->last_mpar_reset);
277 if ((time_delta < 60 * MSEC_PER_SEC) && pcc_ss_data->last_mpar_reset) {
278 pr_debug("PCC cmd for subspace %d not sent due to MPAR limit",
279 pcc_ss_id);
280 ret = -EIO;
281 goto end;
282 }
283 pcc_ss_data->last_mpar_reset = ktime_get();
284 pcc_ss_data->mpar_count = pcc_ss_data->pcc_mpar;
285 }
286 pcc_ss_data->mpar_count--;
287 }
288
289 /* Write to the shared comm region. */
290 writew_relaxed(cmd, &generic_comm_base->command);
291
292 /* Flip CMD COMPLETE bit */
293 writew_relaxed(0, &generic_comm_base->status);
294
295 pcc_ss_data->platform_owns_pcc = true;
296
297 /* Ring doorbell */
298 ret = mbox_send_message(pcc_ss_data->pcc_channel, &cmd);
299 if (ret < 0) {
300 pr_err("Err sending PCC mbox message. ss: %d cmd:%d, ret:%d\n",
301 pcc_ss_id, cmd, ret);
302 goto end;
303 }
304
305 /* wait for completion and check for PCC errro bit */
306 ret = check_pcc_chan(pcc_ss_id, true);
307
308 if (pcc_ss_data->pcc_mrtt)
309 pcc_ss_data->last_cmd_cmpl_time = ktime_get();
310
311 if (pcc_ss_data->pcc_channel->mbox->txdone_irq)
312 mbox_chan_txdone(pcc_ss_data->pcc_channel, ret);
313 else
314 mbox_client_txdone(pcc_ss_data->pcc_channel, ret);
315
316end:
317 if (cmd == CMD_WRITE) {
318 if (unlikely(ret)) {
319 for_each_possible_cpu(i) {
320 struct cpc_desc *desc = per_cpu(cpc_desc_ptr, i);
321
322 if (!desc)
323 continue;
324
325 if (desc->write_cmd_id == pcc_ss_data->pcc_write_cnt)
326 desc->write_cmd_status = ret;
327 }
328 }
329 pcc_ss_data->pcc_write_cnt++;
330 wake_up_all(&pcc_ss_data->pcc_write_wait_q);
331 }
332
333 return ret;
334}
335
336static void cppc_chan_tx_done(struct mbox_client *cl, void *msg, int ret)
337{
338 if (ret < 0)
339 pr_debug("TX did not complete: CMD sent:%x, ret:%d\n",
340 *(u16 *)msg, ret);
341 else
342 pr_debug("TX completed. CMD sent:%x, ret:%d\n",
343 *(u16 *)msg, ret);
344}
345
346static struct mbox_client cppc_mbox_cl = {
347 .tx_done = cppc_chan_tx_done,
348 .knows_txdone = true,
349};
350
351static int acpi_get_psd(struct cpc_desc *cpc_ptr, acpi_handle handle)
352{
353 int result = -EFAULT;
354 acpi_status status = AE_OK;
355 struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
356 struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
357 struct acpi_buffer state = {0, NULL};
358 union acpi_object *psd = NULL;
359 struct acpi_psd_package *pdomain;
360
361 status = acpi_evaluate_object_typed(handle, "_PSD", NULL,
362 &buffer, ACPI_TYPE_PACKAGE);
363 if (status == AE_NOT_FOUND) /* _PSD is optional */
364 return 0;
365 if (ACPI_FAILURE(status))
366 return -ENODEV;
367
368 psd = buffer.pointer;
369 if (!psd || psd->package.count != 1) {
370 pr_debug("Invalid _PSD data\n");
371 goto end;
372 }
373
374 pdomain = &(cpc_ptr->domain_info);
375
376 state.length = sizeof(struct acpi_psd_package);
377 state.pointer = pdomain;
378
379 status = acpi_extract_package(&(psd->package.elements[0]),
380 &format, &state);
381 if (ACPI_FAILURE(status)) {
382 pr_debug("Invalid _PSD data for CPU:%d\n", cpc_ptr->cpu_id);
383 goto end;
384 }
385
386 if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
387 pr_debug("Unknown _PSD:num_entries for CPU:%d\n", cpc_ptr->cpu_id);
388 goto end;
389 }
390
391 if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
392 pr_debug("Unknown _PSD:revision for CPU: %d\n", cpc_ptr->cpu_id);
393 goto end;
394 }
395
396 if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
397 pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
398 pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
399 pr_debug("Invalid _PSD:coord_type for CPU:%d\n", cpc_ptr->cpu_id);
400 goto end;
401 }
402
403 result = 0;
404end:
405 kfree(buffer.pointer);
406 return result;
407}
408
409bool acpi_cpc_valid(void)
410{
411 struct cpc_desc *cpc_ptr;
412 int cpu;
413
414 for_each_possible_cpu(cpu) {
415 cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
416 if (!cpc_ptr)
417 return false;
418 }
419
420 return true;
421}
422EXPORT_SYMBOL_GPL(acpi_cpc_valid);
423
424/**
425 * acpi_get_psd_map - Map the CPUs in the freq domain of a given cpu
426 * @cpu: Find all CPUs that share a domain with cpu.
427 * @cpu_data: Pointer to CPU specific CPPC data including PSD info.
428 *
429 * Return: 0 for success or negative value for err.
430 */
431int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data)
432{
433 struct cpc_desc *cpc_ptr, *match_cpc_ptr;
434 struct acpi_psd_package *match_pdomain;
435 struct acpi_psd_package *pdomain;
436 int count_target, i;
437
438 /*
439 * Now that we have _PSD data from all CPUs, let's setup P-state
440 * domain info.
441 */
442 cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
443 if (!cpc_ptr)
444 return -EFAULT;
445
446 pdomain = &(cpc_ptr->domain_info);
447 cpumask_set_cpu(cpu, cpu_data->shared_cpu_map);
448 if (pdomain->num_processors <= 1)
449 return 0;
450
451 /* Validate the Domain info */
452 count_target = pdomain->num_processors;
453 if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
454 cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ALL;
455 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
456 cpu_data->shared_type = CPUFREQ_SHARED_TYPE_HW;
457 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
458 cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ANY;
459
460 for_each_possible_cpu(i) {
461 if (i == cpu)
462 continue;
463
464 match_cpc_ptr = per_cpu(cpc_desc_ptr, i);
465 if (!match_cpc_ptr)
466 goto err_fault;
467
468 match_pdomain = &(match_cpc_ptr->domain_info);
469 if (match_pdomain->domain != pdomain->domain)
470 continue;
471
472 /* Here i and cpu are in the same domain */
473 if (match_pdomain->num_processors != count_target)
474 goto err_fault;
475
476 if (pdomain->coord_type != match_pdomain->coord_type)
477 goto err_fault;
478
479 cpumask_set_cpu(i, cpu_data->shared_cpu_map);
480 }
481
482 return 0;
483
484err_fault:
485 /* Assume no coordination on any error parsing domain info */
486 cpumask_clear(cpu_data->shared_cpu_map);
487 cpumask_set_cpu(cpu, cpu_data->shared_cpu_map);
488 cpu_data->shared_type = CPUFREQ_SHARED_TYPE_NONE;
489
490 return -EFAULT;
491}
492EXPORT_SYMBOL_GPL(acpi_get_psd_map);
493
494static int register_pcc_channel(int pcc_ss_idx)
495{
496 struct acpi_pcct_hw_reduced *cppc_ss;
497 u64 usecs_lat;
498
499 if (pcc_ss_idx >= 0) {
500 pcc_data[pcc_ss_idx]->pcc_channel =
501 pcc_mbox_request_channel(&cppc_mbox_cl, pcc_ss_idx);
502
503 if (IS_ERR(pcc_data[pcc_ss_idx]->pcc_channel)) {
504 pr_err("Failed to find PCC channel for subspace %d\n",
505 pcc_ss_idx);
506 return -ENODEV;
507 }
508
509 /*
510 * The PCC mailbox controller driver should
511 * have parsed the PCCT (global table of all
512 * PCC channels) and stored pointers to the
513 * subspace communication region in con_priv.
514 */
515 cppc_ss = (pcc_data[pcc_ss_idx]->pcc_channel)->con_priv;
516
517 if (!cppc_ss) {
518 pr_err("No PCC subspace found for %d CPPC\n",
519 pcc_ss_idx);
520 return -ENODEV;
521 }
522
523 /*
524 * cppc_ss->latency is just a Nominal value. In reality
525 * the remote processor could be much slower to reply.
526 * So add an arbitrary amount of wait on top of Nominal.
527 */
528 usecs_lat = NUM_RETRIES * cppc_ss->latency;
529 pcc_data[pcc_ss_idx]->deadline_us = usecs_lat;
530 pcc_data[pcc_ss_idx]->pcc_mrtt = cppc_ss->min_turnaround_time;
531 pcc_data[pcc_ss_idx]->pcc_mpar = cppc_ss->max_access_rate;
532 pcc_data[pcc_ss_idx]->pcc_nominal = cppc_ss->latency;
533
534 pcc_data[pcc_ss_idx]->pcc_comm_addr =
535 acpi_os_ioremap(cppc_ss->base_address, cppc_ss->length);
536 if (!pcc_data[pcc_ss_idx]->pcc_comm_addr) {
537 pr_err("Failed to ioremap PCC comm region mem for %d\n",
538 pcc_ss_idx);
539 return -ENOMEM;
540 }
541
542 /* Set flag so that we don't come here for each CPU. */
543 pcc_data[pcc_ss_idx]->pcc_channel_acquired = true;
544 }
545
546 return 0;
547}
548
549/**
550 * cpc_ffh_supported() - check if FFH reading supported
551 *
552 * Check if the architecture has support for functional fixed hardware
553 * read/write capability.
554 *
555 * Return: true for supported, false for not supported
556 */
557bool __weak cpc_ffh_supported(void)
558{
559 return false;
560}
561
562/**
563 * pcc_data_alloc() - Allocate the pcc_data memory for pcc subspace
564 *
565 * Check and allocate the cppc_pcc_data memory.
566 * In some processor configurations it is possible that same subspace
567 * is shared between multiple CPUs. This is seen especially in CPUs
568 * with hardware multi-threading support.
569 *
570 * Return: 0 for success, errno for failure
571 */
572static int pcc_data_alloc(int pcc_ss_id)
573{
574 if (pcc_ss_id < 0 || pcc_ss_id >= MAX_PCC_SUBSPACES)
575 return -EINVAL;
576
577 if (pcc_data[pcc_ss_id]) {
578 pcc_data[pcc_ss_id]->refcount++;
579 } else {
580 pcc_data[pcc_ss_id] = kzalloc(sizeof(struct cppc_pcc_data),
581 GFP_KERNEL);
582 if (!pcc_data[pcc_ss_id])
583 return -ENOMEM;
584 pcc_data[pcc_ss_id]->refcount++;
585 }
586
587 return 0;
588}
589
590/* Check if CPPC revision + num_ent combination is supported */
591static bool is_cppc_supported(int revision, int num_ent)
592{
593 int expected_num_ent;
594
595 switch (revision) {
596 case CPPC_V2_REV:
597 expected_num_ent = CPPC_V2_NUM_ENT;
598 break;
599 case CPPC_V3_REV:
600 expected_num_ent = CPPC_V3_NUM_ENT;
601 break;
602 default:
603 pr_debug("Firmware exports unsupported CPPC revision: %d\n",
604 revision);
605 return false;
606 }
607
608 if (expected_num_ent != num_ent) {
609 pr_debug("Firmware exports %d entries. Expected: %d for CPPC rev:%d\n",
610 num_ent, expected_num_ent, revision);
611 return false;
612 }
613
614 return true;
615}
616
617/*
618 * An example CPC table looks like the following.
619 *
620 * Name(_CPC, Package()
621 * {
622 * 17,
623 * NumEntries
624 * 1,
625 * // Revision
626 * ResourceTemplate(){Register(PCC, 32, 0, 0x120, 2)},
627 * // Highest Performance
628 * ResourceTemplate(){Register(PCC, 32, 0, 0x124, 2)},
629 * // Nominal Performance
630 * ResourceTemplate(){Register(PCC, 32, 0, 0x128, 2)},
631 * // Lowest Nonlinear Performance
632 * ResourceTemplate(){Register(PCC, 32, 0, 0x12C, 2)},
633 * // Lowest Performance
634 * ResourceTemplate(){Register(PCC, 32, 0, 0x130, 2)},
635 * // Guaranteed Performance Register
636 * ResourceTemplate(){Register(PCC, 32, 0, 0x110, 2)},
637 * // Desired Performance Register
638 * ResourceTemplate(){Register(SystemMemory, 0, 0, 0, 0)},
639 * ..
640 * ..
641 * ..
642 *
643 * }
644 * Each Register() encodes how to access that specific register.
645 * e.g. a sample PCC entry has the following encoding:
646 *
647 * Register (
648 * PCC,
649 * AddressSpaceKeyword
650 * 8,
651 * //RegisterBitWidth
652 * 8,
653 * //RegisterBitOffset
654 * 0x30,
655 * //RegisterAddress
656 * 9
657 * //AccessSize (subspace ID)
658 * 0
659 * )
660 * }
661 */
662
663#ifndef init_freq_invariance_cppc
664static inline void init_freq_invariance_cppc(void) { }
665#endif
666
667/**
668 * acpi_cppc_processor_probe - Search for per CPU _CPC objects.
669 * @pr: Ptr to acpi_processor containing this CPU's logical ID.
670 *
671 * Return: 0 for success or negative value for err.
672 */
673int acpi_cppc_processor_probe(struct acpi_processor *pr)
674{
675 struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
676 union acpi_object *out_obj, *cpc_obj;
677 struct cpc_desc *cpc_ptr;
678 struct cpc_reg *gas_t;
679 struct device *cpu_dev;
680 acpi_handle handle = pr->handle;
681 unsigned int num_ent, i, cpc_rev;
682 int pcc_subspace_id = -1;
683 acpi_status status;
684 int ret = -EFAULT;
685
686 /* Parse the ACPI _CPC table for this CPU. */
687 status = acpi_evaluate_object_typed(handle, "_CPC", NULL, &output,
688 ACPI_TYPE_PACKAGE);
689 if (ACPI_FAILURE(status)) {
690 ret = -ENODEV;
691 goto out_buf_free;
692 }
693
694 out_obj = (union acpi_object *) output.pointer;
695
696 cpc_ptr = kzalloc(sizeof(struct cpc_desc), GFP_KERNEL);
697 if (!cpc_ptr) {
698 ret = -ENOMEM;
699 goto out_buf_free;
700 }
701
702 /* First entry is NumEntries. */
703 cpc_obj = &out_obj->package.elements[0];
704 if (cpc_obj->type == ACPI_TYPE_INTEGER) {
705 num_ent = cpc_obj->integer.value;
706 } else {
707 pr_debug("Unexpected entry type(%d) for NumEntries\n",
708 cpc_obj->type);
709 goto out_free;
710 }
711 cpc_ptr->num_entries = num_ent;
712
713 /* Second entry should be revision. */
714 cpc_obj = &out_obj->package.elements[1];
715 if (cpc_obj->type == ACPI_TYPE_INTEGER) {
716 cpc_rev = cpc_obj->integer.value;
717 } else {
718 pr_debug("Unexpected entry type(%d) for Revision\n",
719 cpc_obj->type);
720 goto out_free;
721 }
722 cpc_ptr->version = cpc_rev;
723
724 if (!is_cppc_supported(cpc_rev, num_ent))
725 goto out_free;
726
727 /* Iterate through remaining entries in _CPC */
728 for (i = 2; i < num_ent; i++) {
729 cpc_obj = &out_obj->package.elements[i];
730
731 if (cpc_obj->type == ACPI_TYPE_INTEGER) {
732 cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_INTEGER;
733 cpc_ptr->cpc_regs[i-2].cpc_entry.int_value = cpc_obj->integer.value;
734 } else if (cpc_obj->type == ACPI_TYPE_BUFFER) {
735 gas_t = (struct cpc_reg *)
736 cpc_obj->buffer.pointer;
737
738 /*
739 * The PCC Subspace index is encoded inside
740 * the CPC table entries. The same PCC index
741 * will be used for all the PCC entries,
742 * so extract it only once.
743 */
744 if (gas_t->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
745 if (pcc_subspace_id < 0) {
746 pcc_subspace_id = gas_t->access_width;
747 if (pcc_data_alloc(pcc_subspace_id))
748 goto out_free;
749 } else if (pcc_subspace_id != gas_t->access_width) {
750 pr_debug("Mismatched PCC ids.\n");
751 goto out_free;
752 }
753 } else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
754 if (gas_t->address) {
755 void __iomem *addr;
756
757 addr = ioremap(gas_t->address, gas_t->bit_width/8);
758 if (!addr)
759 goto out_free;
760 cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;
761 }
762 } else {
763 if (gas_t->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE || !cpc_ffh_supported()) {
764 /* Support only PCC ,SYS MEM and FFH type regs */
765 pr_debug("Unsupported register type: %d\n", gas_t->space_id);
766 goto out_free;
767 }
768 }
769
770 cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_BUFFER;
771 memcpy(&cpc_ptr->cpc_regs[i-2].cpc_entry.reg, gas_t, sizeof(*gas_t));
772 } else {
773 pr_debug("Err in entry:%d in CPC table of CPU:%d\n", i, pr->id);
774 goto out_free;
775 }
776 }
777 per_cpu(cpu_pcc_subspace_idx, pr->id) = pcc_subspace_id;
778
779 /*
780 * Initialize the remaining cpc_regs as unsupported.
781 * Example: In case FW exposes CPPC v2, the below loop will initialize
782 * LOWEST_FREQ and NOMINAL_FREQ regs as unsupported
783 */
784 for (i = num_ent - 2; i < MAX_CPC_REG_ENT; i++) {
785 cpc_ptr->cpc_regs[i].type = ACPI_TYPE_INTEGER;
786 cpc_ptr->cpc_regs[i].cpc_entry.int_value = 0;
787 }
788
789
790 /* Store CPU Logical ID */
791 cpc_ptr->cpu_id = pr->id;
792
793 /* Parse PSD data for this CPU */
794 ret = acpi_get_psd(cpc_ptr, handle);
795 if (ret)
796 goto out_free;
797
798 /* Register PCC channel once for all PCC subspace ID. */
799 if (pcc_subspace_id >= 0 && !pcc_data[pcc_subspace_id]->pcc_channel_acquired) {
800 ret = register_pcc_channel(pcc_subspace_id);
801 if (ret)
802 goto out_free;
803
804 init_rwsem(&pcc_data[pcc_subspace_id]->pcc_lock);
805 init_waitqueue_head(&pcc_data[pcc_subspace_id]->pcc_write_wait_q);
806 }
807
808 /* Everything looks okay */
809 pr_debug("Parsed CPC struct for CPU: %d\n", pr->id);
810
811 /* Add per logical CPU nodes for reading its feedback counters. */
812 cpu_dev = get_cpu_device(pr->id);
813 if (!cpu_dev) {
814 ret = -EINVAL;
815 goto out_free;
816 }
817
818 /* Plug PSD data into this CPU's CPC descriptor. */
819 per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
820
821 ret = kobject_init_and_add(&cpc_ptr->kobj, &cppc_ktype, &cpu_dev->kobj,
822 "acpi_cppc");
823 if (ret) {
824 per_cpu(cpc_desc_ptr, pr->id) = NULL;
825 kobject_put(&cpc_ptr->kobj);
826 goto out_free;
827 }
828
829 init_freq_invariance_cppc();
830
831 kfree(output.pointer);
832 return 0;
833
834out_free:
835 /* Free all the mapped sys mem areas for this CPU */
836 for (i = 2; i < cpc_ptr->num_entries; i++) {
837 void __iomem *addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
838
839 if (addr)
840 iounmap(addr);
841 }
842 kfree(cpc_ptr);
843
844out_buf_free:
845 kfree(output.pointer);
846 return ret;
847}
848EXPORT_SYMBOL_GPL(acpi_cppc_processor_probe);
849
850/**
851 * acpi_cppc_processor_exit - Cleanup CPC structs.
852 * @pr: Ptr to acpi_processor containing this CPU's logical ID.
853 *
854 * Return: Void
855 */
856void acpi_cppc_processor_exit(struct acpi_processor *pr)
857{
858 struct cpc_desc *cpc_ptr;
859 unsigned int i;
860 void __iomem *addr;
861 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, pr->id);
862
863 if (pcc_ss_id >= 0 && pcc_data[pcc_ss_id]) {
864 if (pcc_data[pcc_ss_id]->pcc_channel_acquired) {
865 pcc_data[pcc_ss_id]->refcount--;
866 if (!pcc_data[pcc_ss_id]->refcount) {
867 pcc_mbox_free_channel(pcc_data[pcc_ss_id]->pcc_channel);
868 kfree(pcc_data[pcc_ss_id]);
869 pcc_data[pcc_ss_id] = NULL;
870 }
871 }
872 }
873
874 cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
875 if (!cpc_ptr)
876 return;
877
878 /* Free all the mapped sys mem areas for this CPU */
879 for (i = 2; i < cpc_ptr->num_entries; i++) {
880 addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
881 if (addr)
882 iounmap(addr);
883 }
884
885 kobject_put(&cpc_ptr->kobj);
886 kfree(cpc_ptr);
887}
888EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
889
890/**
891 * cpc_read_ffh() - Read FFH register
892 * @cpunum: CPU number to read
893 * @reg: cppc register information
894 * @val: place holder for return value
895 *
896 * Read bit_width bits from a specified address and bit_offset
897 *
898 * Return: 0 for success and error code
899 */
900int __weak cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
901{
902 return -ENOTSUPP;
903}
904
905/**
906 * cpc_write_ffh() - Write FFH register
907 * @cpunum: CPU number to write
908 * @reg: cppc register information
909 * @val: value to write
910 *
911 * Write value of bit_width bits to a specified address and bit_offset
912 *
913 * Return: 0 for success and error code
914 */
915int __weak cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
916{
917 return -ENOTSUPP;
918}
919
920/*
921 * Since cpc_read and cpc_write are called while holding pcc_lock, it should be
922 * as fast as possible. We have already mapped the PCC subspace during init, so
923 * we can directly write to it.
924 */
925
926static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
927{
928 int ret_val = 0;
929 void __iomem *vaddr = NULL;
930 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
931 struct cpc_reg *reg = ®_res->cpc_entry.reg;
932
933 if (reg_res->type == ACPI_TYPE_INTEGER) {
934 *val = reg_res->cpc_entry.int_value;
935 return ret_val;
936 }
937
938 *val = 0;
939 if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
940 vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
941 else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
942 vaddr = reg_res->sys_mem_vaddr;
943 else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
944 return cpc_read_ffh(cpu, reg, val);
945 else
946 return acpi_os_read_memory((acpi_physical_address)reg->address,
947 val, reg->bit_width);
948
949 switch (reg->bit_width) {
950 case 8:
951 *val = readb_relaxed(vaddr);
952 break;
953 case 16:
954 *val = readw_relaxed(vaddr);
955 break;
956 case 32:
957 *val = readl_relaxed(vaddr);
958 break;
959 case 64:
960 *val = readq_relaxed(vaddr);
961 break;
962 default:
963 pr_debug("Error: Cannot read %u bit width from PCC for ss: %d\n",
964 reg->bit_width, pcc_ss_id);
965 ret_val = -EFAULT;
966 }
967
968 return ret_val;
969}
970
971static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
972{
973 int ret_val = 0;
974 void __iomem *vaddr = NULL;
975 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
976 struct cpc_reg *reg = ®_res->cpc_entry.reg;
977
978 if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
979 vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
980 else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
981 vaddr = reg_res->sys_mem_vaddr;
982 else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
983 return cpc_write_ffh(cpu, reg, val);
984 else
985 return acpi_os_write_memory((acpi_physical_address)reg->address,
986 val, reg->bit_width);
987
988 switch (reg->bit_width) {
989 case 8:
990 writeb_relaxed(val, vaddr);
991 break;
992 case 16:
993 writew_relaxed(val, vaddr);
994 break;
995 case 32:
996 writel_relaxed(val, vaddr);
997 break;
998 case 64:
999 writeq_relaxed(val, vaddr);
1000 break;
1001 default:
1002 pr_debug("Error: Cannot write %u bit width to PCC for ss: %d\n",
1003 reg->bit_width, pcc_ss_id);
1004 ret_val = -EFAULT;
1005 break;
1006 }
1007
1008 return ret_val;
1009}
1010
1011/**
1012 * cppc_get_desired_perf - Get the value of desired performance register.
1013 * @cpunum: CPU from which to get desired performance.
1014 * @desired_perf: address of a variable to store the returned desired performance
1015 *
1016 * Return: 0 for success, -EIO otherwise.
1017 */
1018int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
1019{
1020 struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1021 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1022 struct cpc_register_resource *desired_reg;
1023 struct cppc_pcc_data *pcc_ss_data = NULL;
1024
1025 desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
1026
1027 if (CPC_IN_PCC(desired_reg)) {
1028 int ret = 0;
1029
1030 if (pcc_ss_id < 0)
1031 return -EIO;
1032
1033 pcc_ss_data = pcc_data[pcc_ss_id];
1034
1035 down_write(&pcc_ss_data->pcc_lock);
1036
1037 if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0)
1038 cpc_read(cpunum, desired_reg, desired_perf);
1039 else
1040 ret = -EIO;
1041
1042 up_write(&pcc_ss_data->pcc_lock);
1043
1044 return ret;
1045 }
1046
1047 cpc_read(cpunum, desired_reg, desired_perf);
1048
1049 return 0;
1050}
1051EXPORT_SYMBOL_GPL(cppc_get_desired_perf);
1052
1053/**
1054 * cppc_get_perf_caps - Get a CPU's performance capabilities.
1055 * @cpunum: CPU from which to get capabilities info.
1056 * @perf_caps: ptr to cppc_perf_caps. See cppc_acpi.h
1057 *
1058 * Return: 0 for success with perf_caps populated else -ERRNO.
1059 */
1060int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
1061{
1062 struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1063 struct cpc_register_resource *highest_reg, *lowest_reg,
1064 *lowest_non_linear_reg, *nominal_reg, *guaranteed_reg,
1065 *low_freq_reg = NULL, *nom_freq_reg = NULL;
1066 u64 high, low, guaranteed, nom, min_nonlinear, low_f = 0, nom_f = 0;
1067 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1068 struct cppc_pcc_data *pcc_ss_data = NULL;
1069 int ret = 0, regs_in_pcc = 0;
1070
1071 if (!cpc_desc) {
1072 pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1073 return -ENODEV;
1074 }
1075
1076 highest_reg = &cpc_desc->cpc_regs[HIGHEST_PERF];
1077 lowest_reg = &cpc_desc->cpc_regs[LOWEST_PERF];
1078 lowest_non_linear_reg = &cpc_desc->cpc_regs[LOW_NON_LINEAR_PERF];
1079 nominal_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
1080 low_freq_reg = &cpc_desc->cpc_regs[LOWEST_FREQ];
1081 nom_freq_reg = &cpc_desc->cpc_regs[NOMINAL_FREQ];
1082 guaranteed_reg = &cpc_desc->cpc_regs[GUARANTEED_PERF];
1083
1084 /* Are any of the regs PCC ?*/
1085 if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
1086 CPC_IN_PCC(lowest_non_linear_reg) || CPC_IN_PCC(nominal_reg) ||
1087 CPC_IN_PCC(low_freq_reg) || CPC_IN_PCC(nom_freq_reg)) {
1088 if (pcc_ss_id < 0) {
1089 pr_debug("Invalid pcc_ss_id\n");
1090 return -ENODEV;
1091 }
1092 pcc_ss_data = pcc_data[pcc_ss_id];
1093 regs_in_pcc = 1;
1094 down_write(&pcc_ss_data->pcc_lock);
1095 /* Ring doorbell once to update PCC subspace */
1096 if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
1097 ret = -EIO;
1098 goto out_err;
1099 }
1100 }
1101
1102 cpc_read(cpunum, highest_reg, &high);
1103 perf_caps->highest_perf = high;
1104
1105 cpc_read(cpunum, lowest_reg, &low);
1106 perf_caps->lowest_perf = low;
1107
1108 cpc_read(cpunum, nominal_reg, &nom);
1109 perf_caps->nominal_perf = nom;
1110
1111 if (guaranteed_reg->type != ACPI_TYPE_BUFFER ||
1112 IS_NULL_REG(&guaranteed_reg->cpc_entry.reg)) {
1113 perf_caps->guaranteed_perf = 0;
1114 } else {
1115 cpc_read(cpunum, guaranteed_reg, &guaranteed);
1116 perf_caps->guaranteed_perf = guaranteed;
1117 }
1118
1119 cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear);
1120 perf_caps->lowest_nonlinear_perf = min_nonlinear;
1121
1122 if (!high || !low || !nom || !min_nonlinear)
1123 ret = -EFAULT;
1124
1125 /* Read optional lowest and nominal frequencies if present */
1126 if (CPC_SUPPORTED(low_freq_reg))
1127 cpc_read(cpunum, low_freq_reg, &low_f);
1128
1129 if (CPC_SUPPORTED(nom_freq_reg))
1130 cpc_read(cpunum, nom_freq_reg, &nom_f);
1131
1132 perf_caps->lowest_freq = low_f;
1133 perf_caps->nominal_freq = nom_f;
1134
1135
1136out_err:
1137 if (regs_in_pcc)
1138 up_write(&pcc_ss_data->pcc_lock);
1139 return ret;
1140}
1141EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
1142
1143/**
1144 * cppc_get_perf_ctrs - Read a CPU's performance feedback counters.
1145 * @cpunum: CPU from which to read counters.
1146 * @perf_fb_ctrs: ptr to cppc_perf_fb_ctrs. See cppc_acpi.h
1147 *
1148 * Return: 0 for success with perf_fb_ctrs populated else -ERRNO.
1149 */
1150int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
1151{
1152 struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1153 struct cpc_register_resource *delivered_reg, *reference_reg,
1154 *ref_perf_reg, *ctr_wrap_reg;
1155 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1156 struct cppc_pcc_data *pcc_ss_data = NULL;
1157 u64 delivered, reference, ref_perf, ctr_wrap_time;
1158 int ret = 0, regs_in_pcc = 0;
1159
1160 if (!cpc_desc) {
1161 pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1162 return -ENODEV;
1163 }
1164
1165 delivered_reg = &cpc_desc->cpc_regs[DELIVERED_CTR];
1166 reference_reg = &cpc_desc->cpc_regs[REFERENCE_CTR];
1167 ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
1168 ctr_wrap_reg = &cpc_desc->cpc_regs[CTR_WRAP_TIME];
1169
1170 /*
1171 * If reference perf register is not supported then we should
1172 * use the nominal perf value
1173 */
1174 if (!CPC_SUPPORTED(ref_perf_reg))
1175 ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
1176
1177 /* Are any of the regs PCC ?*/
1178 if (CPC_IN_PCC(delivered_reg) || CPC_IN_PCC(reference_reg) ||
1179 CPC_IN_PCC(ctr_wrap_reg) || CPC_IN_PCC(ref_perf_reg)) {
1180 if (pcc_ss_id < 0) {
1181 pr_debug("Invalid pcc_ss_id\n");
1182 return -ENODEV;
1183 }
1184 pcc_ss_data = pcc_data[pcc_ss_id];
1185 down_write(&pcc_ss_data->pcc_lock);
1186 regs_in_pcc = 1;
1187 /* Ring doorbell once to update PCC subspace */
1188 if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
1189 ret = -EIO;
1190 goto out_err;
1191 }
1192 }
1193
1194 cpc_read(cpunum, delivered_reg, &delivered);
1195 cpc_read(cpunum, reference_reg, &reference);
1196 cpc_read(cpunum, ref_perf_reg, &ref_perf);
1197
1198 /*
1199 * Per spec, if ctr_wrap_time optional register is unsupported, then the
1200 * performance counters are assumed to never wrap during the lifetime of
1201 * platform
1202 */
1203 ctr_wrap_time = (u64)(~((u64)0));
1204 if (CPC_SUPPORTED(ctr_wrap_reg))
1205 cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time);
1206
1207 if (!delivered || !reference || !ref_perf) {
1208 ret = -EFAULT;
1209 goto out_err;
1210 }
1211
1212 perf_fb_ctrs->delivered = delivered;
1213 perf_fb_ctrs->reference = reference;
1214 perf_fb_ctrs->reference_perf = ref_perf;
1215 perf_fb_ctrs->wraparound_time = ctr_wrap_time;
1216out_err:
1217 if (regs_in_pcc)
1218 up_write(&pcc_ss_data->pcc_lock);
1219 return ret;
1220}
1221EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
1222
1223/**
1224 * cppc_set_perf - Set a CPU's performance controls.
1225 * @cpu: CPU for which to set performance controls.
1226 * @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
1227 *
1228 * Return: 0 for success, -ERRNO otherwise.
1229 */
1230int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
1231{
1232 struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1233 struct cpc_register_resource *desired_reg;
1234 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1235 struct cppc_pcc_data *pcc_ss_data = NULL;
1236 int ret = 0;
1237
1238 if (!cpc_desc) {
1239 pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1240 return -ENODEV;
1241 }
1242
1243 desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
1244
1245 /*
1246 * This is Phase-I where we want to write to CPC registers
1247 * -> We want all CPUs to be able to execute this phase in parallel
1248 *
1249 * Since read_lock can be acquired by multiple CPUs simultaneously we
1250 * achieve that goal here
1251 */
1252 if (CPC_IN_PCC(desired_reg)) {
1253 if (pcc_ss_id < 0) {
1254 pr_debug("Invalid pcc_ss_id\n");
1255 return -ENODEV;
1256 }
1257 pcc_ss_data = pcc_data[pcc_ss_id];
1258 down_read(&pcc_ss_data->pcc_lock); /* BEGIN Phase-I */
1259 if (pcc_ss_data->platform_owns_pcc) {
1260 ret = check_pcc_chan(pcc_ss_id, false);
1261 if (ret) {
1262 up_read(&pcc_ss_data->pcc_lock);
1263 return ret;
1264 }
1265 }
1266 /*
1267 * Update the pending_write to make sure a PCC CMD_READ will not
1268 * arrive and steal the channel during the switch to write lock
1269 */
1270 pcc_ss_data->pending_pcc_write_cmd = true;
1271 cpc_desc->write_cmd_id = pcc_ss_data->pcc_write_cnt;
1272 cpc_desc->write_cmd_status = 0;
1273 }
1274
1275 /*
1276 * Skip writing MIN/MAX until Linux knows how to come up with
1277 * useful values.
1278 */
1279 cpc_write(cpu, desired_reg, perf_ctrls->desired_perf);
1280
1281 if (CPC_IN_PCC(desired_reg))
1282 up_read(&pcc_ss_data->pcc_lock); /* END Phase-I */
1283 /*
1284 * This is Phase-II where we transfer the ownership of PCC to Platform
1285 *
1286 * Short Summary: Basically if we think of a group of cppc_set_perf
1287 * requests that happened in short overlapping interval. The last CPU to
1288 * come out of Phase-I will enter Phase-II and ring the doorbell.
1289 *
1290 * We have the following requirements for Phase-II:
1291 * 1. We want to execute Phase-II only when there are no CPUs
1292 * currently executing in Phase-I
1293 * 2. Once we start Phase-II we want to avoid all other CPUs from
1294 * entering Phase-I.
1295 * 3. We want only one CPU among all those who went through Phase-I
1296 * to run phase-II
1297 *
1298 * If write_trylock fails to get the lock and doesn't transfer the
1299 * PCC ownership to the platform, then one of the following will be TRUE
1300 * 1. There is at-least one CPU in Phase-I which will later execute
1301 * write_trylock, so the CPUs in Phase-I will be responsible for
1302 * executing the Phase-II.
1303 * 2. Some other CPU has beaten this CPU to successfully execute the
1304 * write_trylock and has already acquired the write_lock. We know for a
1305 * fact it (other CPU acquiring the write_lock) couldn't have happened
1306 * before this CPU's Phase-I as we held the read_lock.
1307 * 3. Some other CPU executing pcc CMD_READ has stolen the
1308 * down_write, in which case, send_pcc_cmd will check for pending
1309 * CMD_WRITE commands by checking the pending_pcc_write_cmd.
1310 * So this CPU can be certain that its request will be delivered
1311 * So in all cases, this CPU knows that its request will be delivered
1312 * by another CPU and can return
1313 *
1314 * After getting the down_write we still need to check for
1315 * pending_pcc_write_cmd to take care of the following scenario
1316 * The thread running this code could be scheduled out between
1317 * Phase-I and Phase-II. Before it is scheduled back on, another CPU
1318 * could have delivered the request to Platform by triggering the
1319 * doorbell and transferred the ownership of PCC to platform. So this
1320 * avoids triggering an unnecessary doorbell and more importantly before
1321 * triggering the doorbell it makes sure that the PCC channel ownership
1322 * is still with OSPM.
1323 * pending_pcc_write_cmd can also be cleared by a different CPU, if
1324 * there was a pcc CMD_READ waiting on down_write and it steals the lock
1325 * before the pcc CMD_WRITE is completed. send_pcc_cmd checks for this
1326 * case during a CMD_READ and if there are pending writes it delivers
1327 * the write command before servicing the read command
1328 */
1329 if (CPC_IN_PCC(desired_reg)) {
1330 if (down_write_trylock(&pcc_ss_data->pcc_lock)) {/* BEGIN Phase-II */
1331 /* Update only if there are pending write commands */
1332 if (pcc_ss_data->pending_pcc_write_cmd)
1333 send_pcc_cmd(pcc_ss_id, CMD_WRITE);
1334 up_write(&pcc_ss_data->pcc_lock); /* END Phase-II */
1335 } else
1336 /* Wait until pcc_write_cnt is updated by send_pcc_cmd */
1337 wait_event(pcc_ss_data->pcc_write_wait_q,
1338 cpc_desc->write_cmd_id != pcc_ss_data->pcc_write_cnt);
1339
1340 /* send_pcc_cmd updates the status in case of failure */
1341 ret = cpc_desc->write_cmd_status;
1342 }
1343 return ret;
1344}
1345EXPORT_SYMBOL_GPL(cppc_set_perf);
1346
1347/**
1348 * cppc_get_transition_latency - returns frequency transition latency in ns
1349 *
1350 * ACPI CPPC does not explicitly specify how a platform can specify the
1351 * transition latency for performance change requests. The closest we have
1352 * is the timing information from the PCCT tables which provides the info
1353 * on the number and frequency of PCC commands the platform can handle.
1354 */
1355unsigned int cppc_get_transition_latency(int cpu_num)
1356{
1357 /*
1358 * Expected transition latency is based on the PCCT timing values
1359 * Below are definition from ACPI spec:
1360 * pcc_nominal- Expected latency to process a command, in microseconds
1361 * pcc_mpar - The maximum number of periodic requests that the subspace
1362 * channel can support, reported in commands per minute. 0
1363 * indicates no limitation.
1364 * pcc_mrtt - The minimum amount of time that OSPM must wait after the
1365 * completion of a command before issuing the next command,
1366 * in microseconds.
1367 */
1368 unsigned int latency_ns = 0;
1369 struct cpc_desc *cpc_desc;
1370 struct cpc_register_resource *desired_reg;
1371 int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu_num);
1372 struct cppc_pcc_data *pcc_ss_data;
1373
1374 cpc_desc = per_cpu(cpc_desc_ptr, cpu_num);
1375 if (!cpc_desc)
1376 return CPUFREQ_ETERNAL;
1377
1378 desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
1379 if (!CPC_IN_PCC(desired_reg))
1380 return CPUFREQ_ETERNAL;
1381
1382 if (pcc_ss_id < 0)
1383 return CPUFREQ_ETERNAL;
1384
1385 pcc_ss_data = pcc_data[pcc_ss_id];
1386 if (pcc_ss_data->pcc_mpar)
1387 latency_ns = 60 * (1000 * 1000 * 1000 / pcc_ss_data->pcc_mpar);
1388
1389 latency_ns = max(latency_ns, pcc_ss_data->pcc_nominal * 1000);
1390 latency_ns = max(latency_ns, pcc_ss_data->pcc_mrtt * 1000);
1391
1392 return latency_ns;
1393}
1394EXPORT_SYMBOL_GPL(cppc_get_transition_latency);