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#include <linux/dmi.h>
  43#include <linux/units.h>
  44#include <linux/unaligned.h>
  45
  46#include <acpi/cppc_acpi.h>
  47
  48struct cppc_pcc_data {
  49	struct pcc_mbox_chan *pcc_channel;
  50	void __iomem *pcc_comm_addr;
  51	bool pcc_channel_acquired;
  52	unsigned int deadline_us;
  53	unsigned int pcc_mpar, pcc_mrtt, pcc_nominal;
  54
  55	bool pending_pcc_write_cmd;	/* Any pending/batched PCC write cmds? */
  56	bool platform_owns_pcc;		/* Ownership of PCC subspace */
  57	unsigned int pcc_write_cnt;	/* Running count of PCC write commands */
  58
  59	/*
  60	 * Lock to provide controlled access to the PCC channel.
  61	 *
  62	 * For performance critical usecases(currently cppc_set_perf)
  63	 *	We need to take read_lock and check if channel belongs to OSPM
  64	 * before reading or writing to PCC subspace
  65	 *	We need to take write_lock before transferring the channel
  66	 * ownership to the platform via a Doorbell
  67	 *	This allows us to batch a number of CPPC requests if they happen
  68	 * to originate in about the same time
  69	 *
  70	 * For non-performance critical usecases(init)
  71	 *	Take write_lock for all purposes which gives exclusive access
  72	 */
  73	struct rw_semaphore pcc_lock;
  74
  75	/* Wait queue for CPUs whose requests were batched */
  76	wait_queue_head_t pcc_write_wait_q;
  77	ktime_t last_cmd_cmpl_time;
  78	ktime_t last_mpar_reset;
  79	int mpar_count;
  80	int refcount;
  81};
  82
  83/* Array to represent the PCC channel per subspace ID */
  84static struct cppc_pcc_data *pcc_data[MAX_PCC_SUBSPACES];
  85/* The cpu_pcc_subspace_idx contains per CPU subspace ID */
  86static DEFINE_PER_CPU(int, cpu_pcc_subspace_idx);
  87
  88/*
  89 * The cpc_desc structure contains the ACPI register details
  90 * as described in the per CPU _CPC tables. The details
  91 * include the type of register (e.g. PCC, System IO, FFH etc.)
  92 * and destination addresses which lets us READ/WRITE CPU performance
  93 * information using the appropriate I/O methods.
  94 */
  95static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
  96
  97/* pcc mapped address + header size + offset within PCC subspace */
  98#define GET_PCC_VADDR(offs, pcc_ss_id) (pcc_data[pcc_ss_id]->pcc_comm_addr + \
  99						0x8 + (offs))
 100
 101/* Check if a CPC register is in PCC */
 102#define CPC_IN_PCC(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&		\
 103				(cpc)->cpc_entry.reg.space_id ==	\
 104				ACPI_ADR_SPACE_PLATFORM_COMM)
 105
 106/* Check if a CPC register is in FFH */
 107#define CPC_IN_FFH(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&		\
 108				(cpc)->cpc_entry.reg.space_id ==	\
 109				ACPI_ADR_SPACE_FIXED_HARDWARE)
 110
 111/* Check if a CPC register is in SystemMemory */
 112#define CPC_IN_SYSTEM_MEMORY(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&	\
 113				(cpc)->cpc_entry.reg.space_id ==	\
 114				ACPI_ADR_SPACE_SYSTEM_MEMORY)
 115
 116/* Check if a CPC register is in SystemIo */
 117#define CPC_IN_SYSTEM_IO(cpc) ((cpc)->type == ACPI_TYPE_BUFFER &&	\
 118				(cpc)->cpc_entry.reg.space_id ==	\
 119				ACPI_ADR_SPACE_SYSTEM_IO)
 120
 121/* Evaluates to True if reg is a NULL register descriptor */
 122#define IS_NULL_REG(reg) ((reg)->space_id ==  ACPI_ADR_SPACE_SYSTEM_MEMORY && \
 123				(reg)->address == 0 &&			\
 124				(reg)->bit_width == 0 &&		\
 125				(reg)->bit_offset == 0 &&		\
 126				(reg)->access_width == 0)
 127
 128/* Evaluates to True if an optional cpc field is supported */
 129#define CPC_SUPPORTED(cpc) ((cpc)->type == ACPI_TYPE_INTEGER ?		\
 130				!!(cpc)->cpc_entry.int_value :		\
 131				!IS_NULL_REG(&(cpc)->cpc_entry.reg))
 132/*
 133 * Arbitrary Retries in case the remote processor is slow to respond
 134 * to PCC commands. Keeping it high enough to cover emulators where
 135 * the processors run painfully slow.
 136 */
 137#define NUM_RETRIES 500ULL
 138
 139#define OVER_16BTS_MASK ~0xFFFFULL
 140
 141#define define_one_cppc_ro(_name)		\
 142static struct kobj_attribute _name =		\
 143__ATTR(_name, 0444, show_##_name, NULL)
 144
 145#define to_cpc_desc(a) container_of(a, struct cpc_desc, kobj)
 146
 147#define show_cppc_data(access_fn, struct_name, member_name)		\
 148	static ssize_t show_##member_name(struct kobject *kobj,		\
 149				struct kobj_attribute *attr, char *buf)	\
 150	{								\
 151		struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);		\
 152		struct struct_name st_name = {0};			\
 153		int ret;						\
 154									\
 155		ret = access_fn(cpc_ptr->cpu_id, &st_name);		\
 156		if (ret)						\
 157			return ret;					\
 158									\
 159		return sysfs_emit(buf, "%llu\n",		\
 160				(u64)st_name.member_name);		\
 161	}								\
 162	define_one_cppc_ro(member_name)
 163
 164show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, highest_perf);
 165show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_perf);
 166show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_perf);
 167show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_nonlinear_perf);
 168show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, guaranteed_perf);
 169show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_freq);
 170show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq);
 171
 172show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf);
 173show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time);
 174
 175/* Check for valid access_width, otherwise, fallback to using bit_width */
 176#define GET_BIT_WIDTH(reg) ((reg)->access_width ? (8 << ((reg)->access_width - 1)) : (reg)->bit_width)
 177
 178/* Shift and apply the mask for CPC reads/writes */
 179#define MASK_VAL_READ(reg, val) (((val) >> (reg)->bit_offset) &				\
 180					GENMASK(((reg)->bit_width) - 1, 0))
 181#define MASK_VAL_WRITE(reg, prev_val, val)						\
 182	((((val) & GENMASK(((reg)->bit_width) - 1, 0)) << (reg)->bit_offset) |		\
 183	((prev_val) & ~(GENMASK(((reg)->bit_width) - 1, 0) << (reg)->bit_offset)))	\
 184
 185static ssize_t show_feedback_ctrs(struct kobject *kobj,
 186		struct kobj_attribute *attr, char *buf)
 187{
 188	struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);
 189	struct cppc_perf_fb_ctrs fb_ctrs = {0};
 190	int ret;
 191
 192	ret = cppc_get_perf_ctrs(cpc_ptr->cpu_id, &fb_ctrs);
 193	if (ret)
 194		return ret;
 195
 196	return sysfs_emit(buf, "ref:%llu del:%llu\n",
 197			fb_ctrs.reference, fb_ctrs.delivered);
 198}
 199define_one_cppc_ro(feedback_ctrs);
 200
 201static struct attribute *cppc_attrs[] = {
 202	&feedback_ctrs.attr,
 203	&reference_perf.attr,
 204	&wraparound_time.attr,
 205	&highest_perf.attr,
 206	&lowest_perf.attr,
 207	&lowest_nonlinear_perf.attr,
 208	&guaranteed_perf.attr,
 209	&nominal_perf.attr,
 210	&nominal_freq.attr,
 211	&lowest_freq.attr,
 212	NULL
 213};
 214ATTRIBUTE_GROUPS(cppc);
 215
 216static const struct kobj_type cppc_ktype = {
 217	.sysfs_ops = &kobj_sysfs_ops,
 218	.default_groups = cppc_groups,
 219};
 220
 221static int check_pcc_chan(int pcc_ss_id, bool chk_err_bit)
 222{
 223	int ret, status;
 224	struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
 225	struct acpi_pcct_shared_memory __iomem *generic_comm_base =
 226		pcc_ss_data->pcc_comm_addr;
 227
 228	if (!pcc_ss_data->platform_owns_pcc)
 229		return 0;
 230
 231	/*
 232	 * Poll PCC status register every 3us(delay_us) for maximum of
 233	 * deadline_us(timeout_us) until PCC command complete bit is set(cond)
 234	 */
 235	ret = readw_relaxed_poll_timeout(&generic_comm_base->status, status,
 236					status & PCC_CMD_COMPLETE_MASK, 3,
 237					pcc_ss_data->deadline_us);
 238
 239	if (likely(!ret)) {
 240		pcc_ss_data->platform_owns_pcc = false;
 241		if (chk_err_bit && (status & PCC_ERROR_MASK))
 242			ret = -EIO;
 243	}
 244
 245	if (unlikely(ret))
 246		pr_err("PCC check channel failed for ss: %d. ret=%d\n",
 247		       pcc_ss_id, ret);
 248
 249	return ret;
 250}
 251
 252/*
 253 * This function transfers the ownership of the PCC to the platform
 254 * So it must be called while holding write_lock(pcc_lock)
 255 */
 256static int send_pcc_cmd(int pcc_ss_id, u16 cmd)
 257{
 258	int ret = -EIO, i;
 259	struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
 260	struct acpi_pcct_shared_memory __iomem *generic_comm_base =
 261		pcc_ss_data->pcc_comm_addr;
 262	unsigned int time_delta;
 263
 264	/*
 265	 * For CMD_WRITE we know for a fact the caller should have checked
 266	 * the channel before writing to PCC space
 267	 */
 268	if (cmd == CMD_READ) {
 269		/*
 270		 * If there are pending cpc_writes, then we stole the channel
 271		 * before write completion, so first send a WRITE command to
 272		 * platform
 273		 */
 274		if (pcc_ss_data->pending_pcc_write_cmd)
 275			send_pcc_cmd(pcc_ss_id, CMD_WRITE);
 276
 277		ret = check_pcc_chan(pcc_ss_id, false);
 278		if (ret)
 279			goto end;
 280	} else /* CMD_WRITE */
 281		pcc_ss_data->pending_pcc_write_cmd = FALSE;
 282
 283	/*
 284	 * Handle the Minimum Request Turnaround Time(MRTT)
 285	 * "The minimum amount of time that OSPM must wait after the completion
 286	 * of a command before issuing the next command, in microseconds"
 287	 */
 288	if (pcc_ss_data->pcc_mrtt) {
 289		time_delta = ktime_us_delta(ktime_get(),
 290					    pcc_ss_data->last_cmd_cmpl_time);
 291		if (pcc_ss_data->pcc_mrtt > time_delta)
 292			udelay(pcc_ss_data->pcc_mrtt - time_delta);
 293	}
 294
 295	/*
 296	 * Handle the non-zero Maximum Periodic Access Rate(MPAR)
 297	 * "The maximum number of periodic requests that the subspace channel can
 298	 * support, reported in commands per minute. 0 indicates no limitation."
 299	 *
 300	 * This parameter should be ideally zero or large enough so that it can
 301	 * handle maximum number of requests that all the cores in the system can
 302	 * collectively generate. If it is not, we will follow the spec and just
 303	 * not send the request to the platform after hitting the MPAR limit in
 304	 * any 60s window
 305	 */
 306	if (pcc_ss_data->pcc_mpar) {
 307		if (pcc_ss_data->mpar_count == 0) {
 308			time_delta = ktime_ms_delta(ktime_get(),
 309						    pcc_ss_data->last_mpar_reset);
 310			if ((time_delta < 60 * MSEC_PER_SEC) && pcc_ss_data->last_mpar_reset) {
 311				pr_debug("PCC cmd for subspace %d not sent due to MPAR limit",
 312					 pcc_ss_id);
 313				ret = -EIO;
 314				goto end;
 315			}
 316			pcc_ss_data->last_mpar_reset = ktime_get();
 317			pcc_ss_data->mpar_count = pcc_ss_data->pcc_mpar;
 318		}
 319		pcc_ss_data->mpar_count--;
 320	}
 321
 322	/* Write to the shared comm region. */
 323	writew_relaxed(cmd, &generic_comm_base->command);
 324
 325	/* Flip CMD COMPLETE bit */
 326	writew_relaxed(0, &generic_comm_base->status);
 327
 328	pcc_ss_data->platform_owns_pcc = true;
 329
 330	/* Ring doorbell */
 331	ret = mbox_send_message(pcc_ss_data->pcc_channel->mchan, &cmd);
 332	if (ret < 0) {
 333		pr_err("Err sending PCC mbox message. ss: %d cmd:%d, ret:%d\n",
 334		       pcc_ss_id, cmd, ret);
 335		goto end;
 336	}
 337
 338	/* wait for completion and check for PCC error bit */
 339	ret = check_pcc_chan(pcc_ss_id, true);
 340
 341	if (pcc_ss_data->pcc_mrtt)
 342		pcc_ss_data->last_cmd_cmpl_time = ktime_get();
 343
 344	if (pcc_ss_data->pcc_channel->mchan->mbox->txdone_irq)
 345		mbox_chan_txdone(pcc_ss_data->pcc_channel->mchan, ret);
 346	else
 347		mbox_client_txdone(pcc_ss_data->pcc_channel->mchan, ret);
 348
 349end:
 350	if (cmd == CMD_WRITE) {
 351		if (unlikely(ret)) {
 352			for_each_possible_cpu(i) {
 353				struct cpc_desc *desc = per_cpu(cpc_desc_ptr, i);
 354
 355				if (!desc)
 356					continue;
 357
 358				if (desc->write_cmd_id == pcc_ss_data->pcc_write_cnt)
 359					desc->write_cmd_status = ret;
 360			}
 361		}
 362		pcc_ss_data->pcc_write_cnt++;
 363		wake_up_all(&pcc_ss_data->pcc_write_wait_q);
 364	}
 365
 366	return ret;
 367}
 368
 369static void cppc_chan_tx_done(struct mbox_client *cl, void *msg, int ret)
 370{
 371	if (ret < 0)
 372		pr_debug("TX did not complete: CMD sent:%x, ret:%d\n",
 373				*(u16 *)msg, ret);
 374	else
 375		pr_debug("TX completed. CMD sent:%x, ret:%d\n",
 376				*(u16 *)msg, ret);
 377}
 378
 379static struct mbox_client cppc_mbox_cl = {
 380	.tx_done = cppc_chan_tx_done,
 381	.knows_txdone = true,
 382};
 383
 384static int acpi_get_psd(struct cpc_desc *cpc_ptr, acpi_handle handle)
 385{
 386	int result = -EFAULT;
 387	acpi_status status = AE_OK;
 388	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
 389	struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
 390	struct acpi_buffer state = {0, NULL};
 391	union acpi_object  *psd = NULL;
 392	struct acpi_psd_package *pdomain;
 393
 394	status = acpi_evaluate_object_typed(handle, "_PSD", NULL,
 395					    &buffer, ACPI_TYPE_PACKAGE);
 396	if (status == AE_NOT_FOUND)	/* _PSD is optional */
 397		return 0;
 398	if (ACPI_FAILURE(status))
 399		return -ENODEV;
 400
 401	psd = buffer.pointer;
 402	if (!psd || psd->package.count != 1) {
 403		pr_debug("Invalid _PSD data\n");
 404		goto end;
 405	}
 406
 407	pdomain = &(cpc_ptr->domain_info);
 408
 409	state.length = sizeof(struct acpi_psd_package);
 410	state.pointer = pdomain;
 411
 412	status = acpi_extract_package(&(psd->package.elements[0]),
 413		&format, &state);
 414	if (ACPI_FAILURE(status)) {
 415		pr_debug("Invalid _PSD data for CPU:%d\n", cpc_ptr->cpu_id);
 416		goto end;
 417	}
 418
 419	if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
 420		pr_debug("Unknown _PSD:num_entries for CPU:%d\n", cpc_ptr->cpu_id);
 421		goto end;
 422	}
 423
 424	if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
 425		pr_debug("Unknown _PSD:revision for CPU: %d\n", cpc_ptr->cpu_id);
 426		goto end;
 427	}
 428
 429	if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
 430	    pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
 431	    pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
 432		pr_debug("Invalid _PSD:coord_type for CPU:%d\n", cpc_ptr->cpu_id);
 433		goto end;
 434	}
 435
 436	result = 0;
 437end:
 438	kfree(buffer.pointer);
 439	return result;
 440}
 441
 442bool acpi_cpc_valid(void)
 443{
 444	struct cpc_desc *cpc_ptr;
 445	int cpu;
 446
 447	if (acpi_disabled)
 448		return false;
 449
 450	for_each_present_cpu(cpu) {
 451		cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
 452		if (!cpc_ptr)
 453			return false;
 454	}
 455
 456	return true;
 457}
 458EXPORT_SYMBOL_GPL(acpi_cpc_valid);
 459
 460bool cppc_allow_fast_switch(void)
 461{
 462	struct cpc_register_resource *desired_reg;
 463	struct cpc_desc *cpc_ptr;
 464	int cpu;
 465
 466	for_each_possible_cpu(cpu) {
 467		cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
 468		desired_reg = &cpc_ptr->cpc_regs[DESIRED_PERF];
 469		if (!CPC_IN_SYSTEM_MEMORY(desired_reg) &&
 470				!CPC_IN_SYSTEM_IO(desired_reg))
 471			return false;
 472	}
 473
 474	return true;
 475}
 476EXPORT_SYMBOL_GPL(cppc_allow_fast_switch);
 477
 478/**
 479 * acpi_get_psd_map - Map the CPUs in the freq domain of a given cpu
 480 * @cpu: Find all CPUs that share a domain with cpu.
 481 * @cpu_data: Pointer to CPU specific CPPC data including PSD info.
 482 *
 483 *	Return: 0 for success or negative value for err.
 484 */
 485int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data)
 486{
 487	struct cpc_desc *cpc_ptr, *match_cpc_ptr;
 488	struct acpi_psd_package *match_pdomain;
 489	struct acpi_psd_package *pdomain;
 490	int count_target, i;
 491
 492	/*
 493	 * Now that we have _PSD data from all CPUs, let's setup P-state
 494	 * domain info.
 495	 */
 496	cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
 497	if (!cpc_ptr)
 498		return -EFAULT;
 499
 500	pdomain = &(cpc_ptr->domain_info);
 501	cpumask_set_cpu(cpu, cpu_data->shared_cpu_map);
 502	if (pdomain->num_processors <= 1)
 503		return 0;
 504
 505	/* Validate the Domain info */
 506	count_target = pdomain->num_processors;
 507	if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
 508		cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ALL;
 509	else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
 510		cpu_data->shared_type = CPUFREQ_SHARED_TYPE_HW;
 511	else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
 512		cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 513
 514	for_each_possible_cpu(i) {
 515		if (i == cpu)
 516			continue;
 517
 518		match_cpc_ptr = per_cpu(cpc_desc_ptr, i);
 519		if (!match_cpc_ptr)
 520			goto err_fault;
 521
 522		match_pdomain = &(match_cpc_ptr->domain_info);
 523		if (match_pdomain->domain != pdomain->domain)
 524			continue;
 525
 526		/* Here i and cpu are in the same domain */
 527		if (match_pdomain->num_processors != count_target)
 528			goto err_fault;
 529
 530		if (pdomain->coord_type != match_pdomain->coord_type)
 531			goto err_fault;
 532
 533		cpumask_set_cpu(i, cpu_data->shared_cpu_map);
 534	}
 535
 536	return 0;
 537
 538err_fault:
 539	/* Assume no coordination on any error parsing domain info */
 540	cpumask_clear(cpu_data->shared_cpu_map);
 541	cpumask_set_cpu(cpu, cpu_data->shared_cpu_map);
 542	cpu_data->shared_type = CPUFREQ_SHARED_TYPE_NONE;
 543
 544	return -EFAULT;
 545}
 546EXPORT_SYMBOL_GPL(acpi_get_psd_map);
 547
 548static int register_pcc_channel(int pcc_ss_idx)
 549{
 550	struct pcc_mbox_chan *pcc_chan;
 551	u64 usecs_lat;
 552
 553	if (pcc_ss_idx >= 0) {
 554		pcc_chan = pcc_mbox_request_channel(&cppc_mbox_cl, pcc_ss_idx);
 555
 556		if (IS_ERR(pcc_chan)) {
 557			pr_err("Failed to find PCC channel for subspace %d\n",
 558			       pcc_ss_idx);
 559			return -ENODEV;
 560		}
 561
 562		pcc_data[pcc_ss_idx]->pcc_channel = pcc_chan;
 563		/*
 564		 * cppc_ss->latency is just a Nominal value. In reality
 565		 * the remote processor could be much slower to reply.
 566		 * So add an arbitrary amount of wait on top of Nominal.
 567		 */
 568		usecs_lat = NUM_RETRIES * pcc_chan->latency;
 569		pcc_data[pcc_ss_idx]->deadline_us = usecs_lat;
 570		pcc_data[pcc_ss_idx]->pcc_mrtt = pcc_chan->min_turnaround_time;
 571		pcc_data[pcc_ss_idx]->pcc_mpar = pcc_chan->max_access_rate;
 572		pcc_data[pcc_ss_idx]->pcc_nominal = pcc_chan->latency;
 573
 574		pcc_data[pcc_ss_idx]->pcc_comm_addr =
 575			acpi_os_ioremap(pcc_chan->shmem_base_addr,
 576					pcc_chan->shmem_size);
 577		if (!pcc_data[pcc_ss_idx]->pcc_comm_addr) {
 578			pr_err("Failed to ioremap PCC comm region mem for %d\n",
 579			       pcc_ss_idx);
 580			return -ENOMEM;
 581		}
 582
 583		/* Set flag so that we don't come here for each CPU. */
 584		pcc_data[pcc_ss_idx]->pcc_channel_acquired = true;
 585	}
 586
 587	return 0;
 588}
 589
 590/**
 591 * cpc_ffh_supported() - check if FFH reading supported
 592 *
 593 * Check if the architecture has support for functional fixed hardware
 594 * read/write capability.
 595 *
 596 * Return: true for supported, false for not supported
 597 */
 598bool __weak cpc_ffh_supported(void)
 599{
 600	return false;
 601}
 602
 603/**
 604 * cpc_supported_by_cpu() - check if CPPC is supported by CPU
 605 *
 606 * Check if the architectural support for CPPC is present even
 607 * if the _OSC hasn't prescribed it
 608 *
 609 * Return: true for supported, false for not supported
 610 */
 611bool __weak cpc_supported_by_cpu(void)
 612{
 613	return false;
 614}
 615
 616/**
 617 * pcc_data_alloc() - Allocate the pcc_data memory for pcc subspace
 618 * @pcc_ss_id: PCC Subspace index as in the PCC client ACPI package.
 619 *
 620 * Check and allocate the cppc_pcc_data memory.
 621 * In some processor configurations it is possible that same subspace
 622 * is shared between multiple CPUs. This is seen especially in CPUs
 623 * with hardware multi-threading support.
 624 *
 625 * Return: 0 for success, errno for failure
 626 */
 627static int pcc_data_alloc(int pcc_ss_id)
 628{
 629	if (pcc_ss_id < 0 || pcc_ss_id >= MAX_PCC_SUBSPACES)
 630		return -EINVAL;
 631
 632	if (pcc_data[pcc_ss_id]) {
 633		pcc_data[pcc_ss_id]->refcount++;
 634	} else {
 635		pcc_data[pcc_ss_id] = kzalloc(sizeof(struct cppc_pcc_data),
 636					      GFP_KERNEL);
 637		if (!pcc_data[pcc_ss_id])
 638			return -ENOMEM;
 639		pcc_data[pcc_ss_id]->refcount++;
 640	}
 641
 642	return 0;
 643}
 644
 645/*
 646 * An example CPC table looks like the following.
 647 *
 648 *  Name (_CPC, Package() {
 649 *      17,							// NumEntries
 650 *      1,							// Revision
 651 *      ResourceTemplate() {Register(PCC, 32, 0, 0x120, 2)},	// Highest Performance
 652 *      ResourceTemplate() {Register(PCC, 32, 0, 0x124, 2)},	// Nominal Performance
 653 *      ResourceTemplate() {Register(PCC, 32, 0, 0x128, 2)},	// Lowest Nonlinear Performance
 654 *      ResourceTemplate() {Register(PCC, 32, 0, 0x12C, 2)},	// Lowest Performance
 655 *      ResourceTemplate() {Register(PCC, 32, 0, 0x130, 2)},	// Guaranteed Performance Register
 656 *      ResourceTemplate() {Register(PCC, 32, 0, 0x110, 2)},	// Desired Performance Register
 657 *      ResourceTemplate() {Register(SystemMemory, 0, 0, 0, 0)},
 658 *      ...
 659 *      ...
 660 *      ...
 661 *  }
 662 * Each Register() encodes how to access that specific register.
 663 * e.g. a sample PCC entry has the following encoding:
 664 *
 665 *  Register (
 666 *      PCC,	// AddressSpaceKeyword
 667 *      8,	// RegisterBitWidth
 668 *      8,	// RegisterBitOffset
 669 *      0x30,	// RegisterAddress
 670 *      9,	// AccessSize (subspace ID)
 671 *  )
 672 */
 673
 
 
 
 
 674/**
 675 * acpi_cppc_processor_probe - Search for per CPU _CPC objects.
 676 * @pr: Ptr to acpi_processor containing this CPU's logical ID.
 677 *
 678 *	Return: 0 for success or negative value for err.
 679 */
 680int acpi_cppc_processor_probe(struct acpi_processor *pr)
 681{
 682	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 683	union acpi_object *out_obj, *cpc_obj;
 684	struct cpc_desc *cpc_ptr;
 685	struct cpc_reg *gas_t;
 686	struct device *cpu_dev;
 687	acpi_handle handle = pr->handle;
 688	unsigned int num_ent, i, cpc_rev;
 689	int pcc_subspace_id = -1;
 690	acpi_status status;
 691	int ret = -ENODATA;
 692
 693	if (!osc_sb_cppc2_support_acked) {
 694		pr_debug("CPPC v2 _OSC not acked\n");
 695		if (!cpc_supported_by_cpu()) {
 696			pr_debug("CPPC is not supported by the CPU\n");
 697			return -ENODEV;
 698		}
 699	}
 700
 701	/* Parse the ACPI _CPC table for this CPU. */
 702	status = acpi_evaluate_object_typed(handle, "_CPC", NULL, &output,
 703			ACPI_TYPE_PACKAGE);
 704	if (ACPI_FAILURE(status)) {
 705		ret = -ENODEV;
 706		goto out_buf_free;
 707	}
 708
 709	out_obj = (union acpi_object *) output.pointer;
 710
 711	cpc_ptr = kzalloc(sizeof(struct cpc_desc), GFP_KERNEL);
 712	if (!cpc_ptr) {
 713		ret = -ENOMEM;
 714		goto out_buf_free;
 715	}
 716
 717	/* First entry is NumEntries. */
 718	cpc_obj = &out_obj->package.elements[0];
 719	if (cpc_obj->type == ACPI_TYPE_INTEGER)	{
 720		num_ent = cpc_obj->integer.value;
 721		if (num_ent <= 1) {
 722			pr_debug("Unexpected _CPC NumEntries value (%d) for CPU:%d\n",
 723				 num_ent, pr->id);
 724			goto out_free;
 725		}
 726	} else {
 727		pr_debug("Unexpected _CPC NumEntries entry type (%d) for CPU:%d\n",
 728			 cpc_obj->type, pr->id);
 729		goto out_free;
 730	}
 731
 732	/* Second entry should be revision. */
 733	cpc_obj = &out_obj->package.elements[1];
 734	if (cpc_obj->type == ACPI_TYPE_INTEGER)	{
 735		cpc_rev = cpc_obj->integer.value;
 736	} else {
 737		pr_debug("Unexpected _CPC Revision entry type (%d) for CPU:%d\n",
 738			 cpc_obj->type, pr->id);
 739		goto out_free;
 740	}
 741
 742	if (cpc_rev < CPPC_V2_REV) {
 743		pr_debug("Unsupported _CPC Revision (%d) for CPU:%d\n", cpc_rev,
 744			 pr->id);
 745		goto out_free;
 746	}
 747
 748	/*
 749	 * Disregard _CPC if the number of entries in the return pachage is not
 750	 * as expected, but support future revisions being proper supersets of
 751	 * the v3 and only causing more entries to be returned by _CPC.
 752	 */
 753	if ((cpc_rev == CPPC_V2_REV && num_ent != CPPC_V2_NUM_ENT) ||
 754	    (cpc_rev == CPPC_V3_REV && num_ent != CPPC_V3_NUM_ENT) ||
 755	    (cpc_rev > CPPC_V3_REV && num_ent <= CPPC_V3_NUM_ENT)) {
 756		pr_debug("Unexpected number of _CPC return package entries (%d) for CPU:%d\n",
 757			 num_ent, pr->id);
 758		goto out_free;
 759	}
 760	if (cpc_rev > CPPC_V3_REV) {
 761		num_ent = CPPC_V3_NUM_ENT;
 762		cpc_rev = CPPC_V3_REV;
 763	}
 764
 765	cpc_ptr->num_entries = num_ent;
 766	cpc_ptr->version = cpc_rev;
 767
 768	/* Iterate through remaining entries in _CPC */
 769	for (i = 2; i < num_ent; i++) {
 770		cpc_obj = &out_obj->package.elements[i];
 771
 772		if (cpc_obj->type == ACPI_TYPE_INTEGER)	{
 773			cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_INTEGER;
 774			cpc_ptr->cpc_regs[i-2].cpc_entry.int_value = cpc_obj->integer.value;
 775		} else if (cpc_obj->type == ACPI_TYPE_BUFFER) {
 776			gas_t = (struct cpc_reg *)
 777				cpc_obj->buffer.pointer;
 778
 779			/*
 780			 * The PCC Subspace index is encoded inside
 781			 * the CPC table entries. The same PCC index
 782			 * will be used for all the PCC entries,
 783			 * so extract it only once.
 784			 */
 785			if (gas_t->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
 786				if (pcc_subspace_id < 0) {
 787					pcc_subspace_id = gas_t->access_width;
 788					if (pcc_data_alloc(pcc_subspace_id))
 789						goto out_free;
 790				} else if (pcc_subspace_id != gas_t->access_width) {
 791					pr_debug("Mismatched PCC ids in _CPC for CPU:%d\n",
 792						 pr->id);
 793					goto out_free;
 794				}
 795			} else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
 796				if (gas_t->address) {
 797					void __iomem *addr;
 798					size_t access_width;
 799
 800					if (!osc_cpc_flexible_adr_space_confirmed) {
 801						pr_debug("Flexible address space capability not supported\n");
 802						if (!cpc_supported_by_cpu())
 803							goto out_free;
 804					}
 805
 806					access_width = GET_BIT_WIDTH(gas_t) / 8;
 807					addr = ioremap(gas_t->address, access_width);
 808					if (!addr)
 809						goto out_free;
 810					cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;
 811				}
 812			} else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
 813				if (gas_t->access_width < 1 || gas_t->access_width > 3) {
 814					/*
 815					 * 1 = 8-bit, 2 = 16-bit, and 3 = 32-bit.
 816					 * SystemIO doesn't implement 64-bit
 817					 * registers.
 818					 */
 819					pr_debug("Invalid access width %d for SystemIO register in _CPC\n",
 820						 gas_t->access_width);
 821					goto out_free;
 822				}
 823				if (gas_t->address & OVER_16BTS_MASK) {
 824					/* SystemIO registers use 16-bit integer addresses */
 825					pr_debug("Invalid IO port %llu for SystemIO register in _CPC\n",
 826						 gas_t->address);
 827					goto out_free;
 828				}
 829				if (!osc_cpc_flexible_adr_space_confirmed) {
 830					pr_debug("Flexible address space capability not supported\n");
 831					if (!cpc_supported_by_cpu())
 832						goto out_free;
 833				}
 834			} else {
 835				if (gas_t->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE || !cpc_ffh_supported()) {
 836					/* Support only PCC, SystemMemory, SystemIO, and FFH type regs. */
 837					pr_debug("Unsupported register type (%d) in _CPC\n",
 838						 gas_t->space_id);
 839					goto out_free;
 840				}
 841			}
 842
 843			cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_BUFFER;
 844			memcpy(&cpc_ptr->cpc_regs[i-2].cpc_entry.reg, gas_t, sizeof(*gas_t));
 845		} else {
 846			pr_debug("Invalid entry type (%d) in _CPC for CPU:%d\n",
 847				 i, pr->id);
 848			goto out_free;
 849		}
 850	}
 851	per_cpu(cpu_pcc_subspace_idx, pr->id) = pcc_subspace_id;
 852
 853	/*
 854	 * Initialize the remaining cpc_regs as unsupported.
 855	 * Example: In case FW exposes CPPC v2, the below loop will initialize
 856	 * LOWEST_FREQ and NOMINAL_FREQ regs as unsupported
 857	 */
 858	for (i = num_ent - 2; i < MAX_CPC_REG_ENT; i++) {
 859		cpc_ptr->cpc_regs[i].type = ACPI_TYPE_INTEGER;
 860		cpc_ptr->cpc_regs[i].cpc_entry.int_value = 0;
 861	}
 862
 863
 864	/* Store CPU Logical ID */
 865	cpc_ptr->cpu_id = pr->id;
 866	raw_spin_lock_init(&cpc_ptr->rmw_lock);
 867
 868	/* Parse PSD data for this CPU */
 869	ret = acpi_get_psd(cpc_ptr, handle);
 870	if (ret)
 871		goto out_free;
 872
 873	/* Register PCC channel once for all PCC subspace ID. */
 874	if (pcc_subspace_id >= 0 && !pcc_data[pcc_subspace_id]->pcc_channel_acquired) {
 875		ret = register_pcc_channel(pcc_subspace_id);
 876		if (ret)
 877			goto out_free;
 878
 879		init_rwsem(&pcc_data[pcc_subspace_id]->pcc_lock);
 880		init_waitqueue_head(&pcc_data[pcc_subspace_id]->pcc_write_wait_q);
 881	}
 882
 883	/* Everything looks okay */
 884	pr_debug("Parsed CPC struct for CPU: %d\n", pr->id);
 885
 886	/* Add per logical CPU nodes for reading its feedback counters. */
 887	cpu_dev = get_cpu_device(pr->id);
 888	if (!cpu_dev) {
 889		ret = -EINVAL;
 890		goto out_free;
 891	}
 892
 893	/* Plug PSD data into this CPU's CPC descriptor. */
 894	per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
 895
 896	ret = kobject_init_and_add(&cpc_ptr->kobj, &cppc_ktype, &cpu_dev->kobj,
 897			"acpi_cppc");
 898	if (ret) {
 899		per_cpu(cpc_desc_ptr, pr->id) = NULL;
 900		kobject_put(&cpc_ptr->kobj);
 901		goto out_free;
 902	}
 903
 
 
 904	kfree(output.pointer);
 905	return 0;
 906
 907out_free:
 908	/* Free all the mapped sys mem areas for this CPU */
 909	for (i = 2; i < cpc_ptr->num_entries; i++) {
 910		void __iomem *addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
 911
 912		if (addr)
 913			iounmap(addr);
 914	}
 915	kfree(cpc_ptr);
 916
 917out_buf_free:
 918	kfree(output.pointer);
 919	return ret;
 920}
 921EXPORT_SYMBOL_GPL(acpi_cppc_processor_probe);
 922
 923/**
 924 * acpi_cppc_processor_exit - Cleanup CPC structs.
 925 * @pr: Ptr to acpi_processor containing this CPU's logical ID.
 926 *
 927 * Return: Void
 928 */
 929void acpi_cppc_processor_exit(struct acpi_processor *pr)
 930{
 931	struct cpc_desc *cpc_ptr;
 932	unsigned int i;
 933	void __iomem *addr;
 934	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, pr->id);
 935
 936	if (pcc_ss_id >= 0 && pcc_data[pcc_ss_id]) {
 937		if (pcc_data[pcc_ss_id]->pcc_channel_acquired) {
 938			pcc_data[pcc_ss_id]->refcount--;
 939			if (!pcc_data[pcc_ss_id]->refcount) {
 940				pcc_mbox_free_channel(pcc_data[pcc_ss_id]->pcc_channel);
 941				kfree(pcc_data[pcc_ss_id]);
 942				pcc_data[pcc_ss_id] = NULL;
 943			}
 944		}
 945	}
 946
 947	cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
 948	if (!cpc_ptr)
 949		return;
 950
 951	/* Free all the mapped sys mem areas for this CPU */
 952	for (i = 2; i < cpc_ptr->num_entries; i++) {
 953		addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
 954		if (addr)
 955			iounmap(addr);
 956	}
 957
 958	kobject_put(&cpc_ptr->kobj);
 959	kfree(cpc_ptr);
 960}
 961EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
 962
 963/**
 964 * cpc_read_ffh() - Read FFH register
 965 * @cpunum:	CPU number to read
 966 * @reg:	cppc register information
 967 * @val:	place holder for return value
 968 *
 969 * Read bit_width bits from a specified address and bit_offset
 970 *
 971 * Return: 0 for success and error code
 972 */
 973int __weak cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
 974{
 975	return -ENOTSUPP;
 976}
 977
 978/**
 979 * cpc_write_ffh() - Write FFH register
 980 * @cpunum:	CPU number to write
 981 * @reg:	cppc register information
 982 * @val:	value to write
 983 *
 984 * Write value of bit_width bits to a specified address and bit_offset
 985 *
 986 * Return: 0 for success and error code
 987 */
 988int __weak cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
 989{
 990	return -ENOTSUPP;
 991}
 992
 993/*
 994 * Since cpc_read and cpc_write are called while holding pcc_lock, it should be
 995 * as fast as possible. We have already mapped the PCC subspace during init, so
 996 * we can directly write to it.
 997 */
 998
 999static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
1000{
1001	void __iomem *vaddr = NULL;
1002	int size;
1003	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1004	struct cpc_reg *reg = &reg_res->cpc_entry.reg;
1005
1006	if (reg_res->type == ACPI_TYPE_INTEGER) {
1007		*val = reg_res->cpc_entry.int_value;
1008		return 0;
1009	}
1010
1011	*val = 0;
1012	size = GET_BIT_WIDTH(reg);
1013
1014	if (IS_ENABLED(CONFIG_HAS_IOPORT) &&
1015	    reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
1016		u32 val_u32;
1017		acpi_status status;
1018
1019		status = acpi_os_read_port((acpi_io_address)reg->address,
1020					   &val_u32, size);
1021		if (ACPI_FAILURE(status)) {
1022			pr_debug("Error: Failed to read SystemIO port %llx\n",
1023				 reg->address);
1024			return -EFAULT;
1025		}
1026
1027		*val = val_u32;
1028		return 0;
1029	} else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0) {
1030		/*
1031		 * For registers in PCC space, the register size is determined
1032		 * by the bit width field; the access size is used to indicate
1033		 * the PCC subspace id.
1034		 */
1035		size = reg->bit_width;
1036		vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
1037	}
1038	else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
1039		vaddr = reg_res->sys_mem_vaddr;
1040	else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
1041		return cpc_read_ffh(cpu, reg, val);
1042	else
1043		return acpi_os_read_memory((acpi_physical_address)reg->address,
1044				val, size);
1045
1046	switch (size) {
1047	case 8:
1048		*val = readb_relaxed(vaddr);
1049		break;
1050	case 16:
1051		*val = readw_relaxed(vaddr);
1052		break;
1053	case 32:
1054		*val = readl_relaxed(vaddr);
1055		break;
1056	case 64:
1057		*val = readq_relaxed(vaddr);
1058		break;
1059	default:
1060		if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
1061			pr_debug("Error: Cannot read %u bit width from system memory: 0x%llx\n",
1062				size, reg->address);
1063		} else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
1064			pr_debug("Error: Cannot read %u bit width from PCC for ss: %d\n",
1065				size, pcc_ss_id);
1066		}
1067		return -EFAULT;
1068	}
1069
1070	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
1071		*val = MASK_VAL_READ(reg, *val);
1072
1073	return 0;
1074}
1075
1076static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
1077{
1078	int ret_val = 0;
1079	int size;
1080	u64 prev_val;
1081	void __iomem *vaddr = NULL;
1082	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1083	struct cpc_reg *reg = &reg_res->cpc_entry.reg;
1084	struct cpc_desc *cpc_desc;
1085	unsigned long flags;
1086
1087	size = GET_BIT_WIDTH(reg);
1088
1089	if (IS_ENABLED(CONFIG_HAS_IOPORT) &&
1090	    reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
1091		acpi_status status;
1092
1093		status = acpi_os_write_port((acpi_io_address)reg->address,
1094					    (u32)val, size);
1095		if (ACPI_FAILURE(status)) {
1096			pr_debug("Error: Failed to write SystemIO port %llx\n",
1097				 reg->address);
1098			return -EFAULT;
1099		}
1100
1101		return 0;
1102	} else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0) {
1103		/*
1104		 * For registers in PCC space, the register size is determined
1105		 * by the bit width field; the access size is used to indicate
1106		 * the PCC subspace id.
1107		 */
1108		size = reg->bit_width;
1109		vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
1110	}
1111	else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
1112		vaddr = reg_res->sys_mem_vaddr;
1113	else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
1114		return cpc_write_ffh(cpu, reg, val);
1115	else
1116		return acpi_os_write_memory((acpi_physical_address)reg->address,
1117				val, size);
1118
1119	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
1120		cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1121		if (!cpc_desc) {
1122			pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1123			return -ENODEV;
1124		}
1125
1126		raw_spin_lock_irqsave(&cpc_desc->rmw_lock, flags);
1127		switch (size) {
1128		case 8:
1129			prev_val = readb_relaxed(vaddr);
1130			break;
1131		case 16:
1132			prev_val = readw_relaxed(vaddr);
1133			break;
1134		case 32:
1135			prev_val = readl_relaxed(vaddr);
1136			break;
1137		case 64:
1138			prev_val = readq_relaxed(vaddr);
1139			break;
1140		default:
1141			raw_spin_unlock_irqrestore(&cpc_desc->rmw_lock, flags);
1142			return -EFAULT;
1143		}
1144		val = MASK_VAL_WRITE(reg, prev_val, val);
1145	}
1146
1147	switch (size) {
1148	case 8:
1149		writeb_relaxed(val, vaddr);
1150		break;
1151	case 16:
1152		writew_relaxed(val, vaddr);
1153		break;
1154	case 32:
1155		writel_relaxed(val, vaddr);
1156		break;
1157	case 64:
1158		writeq_relaxed(val, vaddr);
1159		break;
1160	default:
1161		if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
1162			pr_debug("Error: Cannot write %u bit width to system memory: 0x%llx\n",
1163				size, reg->address);
1164		} else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
1165			pr_debug("Error: Cannot write %u bit width to PCC for ss: %d\n",
1166				size, pcc_ss_id);
1167		}
1168		ret_val = -EFAULT;
1169		break;
1170	}
1171
1172	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
1173		raw_spin_unlock_irqrestore(&cpc_desc->rmw_lock, flags);
1174
1175	return ret_val;
1176}
1177
1178static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
1179{
1180	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1181	struct cpc_register_resource *reg;
1182
1183	if (!cpc_desc) {
1184		pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1185		return -ENODEV;
1186	}
1187
1188	reg = &cpc_desc->cpc_regs[reg_idx];
1189
1190	if (CPC_IN_PCC(reg)) {
1191		int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1192		struct cppc_pcc_data *pcc_ss_data = NULL;
1193		int ret = 0;
1194
1195		if (pcc_ss_id < 0)
1196			return -EIO;
1197
1198		pcc_ss_data = pcc_data[pcc_ss_id];
1199
1200		down_write(&pcc_ss_data->pcc_lock);
1201
1202		if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0)
1203			cpc_read(cpunum, reg, perf);
1204		else
1205			ret = -EIO;
1206
1207		up_write(&pcc_ss_data->pcc_lock);
1208
1209		return ret;
1210	}
1211
1212	cpc_read(cpunum, reg, perf);
1213
1214	return 0;
1215}
1216
1217/**
1218 * cppc_get_desired_perf - Get the desired performance register value.
1219 * @cpunum: CPU from which to get desired performance.
1220 * @desired_perf: Return address.
1221 *
1222 * Return: 0 for success, -EIO otherwise.
1223 */
1224int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
1225{
1226	return cppc_get_perf(cpunum, DESIRED_PERF, desired_perf);
1227}
1228EXPORT_SYMBOL_GPL(cppc_get_desired_perf);
1229
1230/**
1231 * cppc_get_nominal_perf - Get the nominal performance register value.
1232 * @cpunum: CPU from which to get nominal performance.
1233 * @nominal_perf: Return address.
1234 *
1235 * Return: 0 for success, -EIO otherwise.
1236 */
1237int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
1238{
1239	return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
1240}
1241
1242/**
1243 * cppc_get_highest_perf - Get the highest performance register value.
1244 * @cpunum: CPU from which to get highest performance.
1245 * @highest_perf: Return address.
1246 *
1247 * Return: 0 for success, -EIO otherwise.
1248 */
1249int cppc_get_highest_perf(int cpunum, u64 *highest_perf)
1250{
1251	return cppc_get_perf(cpunum, HIGHEST_PERF, highest_perf);
1252}
1253EXPORT_SYMBOL_GPL(cppc_get_highest_perf);
1254
1255/**
1256 * cppc_get_epp_perf - Get the epp register value.
1257 * @cpunum: CPU from which to get epp preference value.
1258 * @epp_perf: Return address.
1259 *
1260 * Return: 0 for success, -EIO otherwise.
1261 */
1262int cppc_get_epp_perf(int cpunum, u64 *epp_perf)
1263{
1264	return cppc_get_perf(cpunum, ENERGY_PERF, epp_perf);
1265}
1266EXPORT_SYMBOL_GPL(cppc_get_epp_perf);
1267
1268/**
1269 * cppc_get_perf_caps - Get a CPU's performance capabilities.
1270 * @cpunum: CPU from which to get capabilities info.
1271 * @perf_caps: ptr to cppc_perf_caps. See cppc_acpi.h
1272 *
1273 * Return: 0 for success with perf_caps populated else -ERRNO.
1274 */
1275int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
1276{
1277	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1278	struct cpc_register_resource *highest_reg, *lowest_reg,
1279		*lowest_non_linear_reg, *nominal_reg, *guaranteed_reg,
1280		*low_freq_reg = NULL, *nom_freq_reg = NULL;
1281	u64 high, low, guaranteed, nom, min_nonlinear, low_f = 0, nom_f = 0;
1282	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1283	struct cppc_pcc_data *pcc_ss_data = NULL;
1284	int ret = 0, regs_in_pcc = 0;
1285
1286	if (!cpc_desc) {
1287		pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1288		return -ENODEV;
1289	}
1290
1291	highest_reg = &cpc_desc->cpc_regs[HIGHEST_PERF];
1292	lowest_reg = &cpc_desc->cpc_regs[LOWEST_PERF];
1293	lowest_non_linear_reg = &cpc_desc->cpc_regs[LOW_NON_LINEAR_PERF];
1294	nominal_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
1295	low_freq_reg = &cpc_desc->cpc_regs[LOWEST_FREQ];
1296	nom_freq_reg = &cpc_desc->cpc_regs[NOMINAL_FREQ];
1297	guaranteed_reg = &cpc_desc->cpc_regs[GUARANTEED_PERF];
1298
1299	/* Are any of the regs PCC ?*/
1300	if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
1301		CPC_IN_PCC(lowest_non_linear_reg) || CPC_IN_PCC(nominal_reg) ||
1302		CPC_IN_PCC(low_freq_reg) || CPC_IN_PCC(nom_freq_reg)) {
1303		if (pcc_ss_id < 0) {
1304			pr_debug("Invalid pcc_ss_id\n");
1305			return -ENODEV;
1306		}
1307		pcc_ss_data = pcc_data[pcc_ss_id];
1308		regs_in_pcc = 1;
1309		down_write(&pcc_ss_data->pcc_lock);
1310		/* Ring doorbell once to update PCC subspace */
1311		if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
1312			ret = -EIO;
1313			goto out_err;
1314		}
1315	}
1316
1317	cpc_read(cpunum, highest_reg, &high);
1318	perf_caps->highest_perf = high;
1319
1320	cpc_read(cpunum, lowest_reg, &low);
1321	perf_caps->lowest_perf = low;
1322
1323	cpc_read(cpunum, nominal_reg, &nom);
1324	perf_caps->nominal_perf = nom;
1325
1326	if (guaranteed_reg->type != ACPI_TYPE_BUFFER  ||
1327	    IS_NULL_REG(&guaranteed_reg->cpc_entry.reg)) {
1328		perf_caps->guaranteed_perf = 0;
1329	} else {
1330		cpc_read(cpunum, guaranteed_reg, &guaranteed);
1331		perf_caps->guaranteed_perf = guaranteed;
1332	}
1333
1334	cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear);
1335	perf_caps->lowest_nonlinear_perf = min_nonlinear;
1336
1337	if (!high || !low || !nom || !min_nonlinear)
1338		ret = -EFAULT;
1339
1340	/* Read optional lowest and nominal frequencies if present */
1341	if (CPC_SUPPORTED(low_freq_reg))
1342		cpc_read(cpunum, low_freq_reg, &low_f);
1343
1344	if (CPC_SUPPORTED(nom_freq_reg))
1345		cpc_read(cpunum, nom_freq_reg, &nom_f);
1346
1347	perf_caps->lowest_freq = low_f;
1348	perf_caps->nominal_freq = nom_f;
1349
1350
1351out_err:
1352	if (regs_in_pcc)
1353		up_write(&pcc_ss_data->pcc_lock);
1354	return ret;
1355}
1356EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
1357
1358/**
1359 * cppc_perf_ctrs_in_pcc - Check if any perf counters are in a PCC region.
1360 *
1361 * CPPC has flexibility about how CPU performance counters are accessed.
1362 * One of the choices is PCC regions, which can have a high access latency. This
1363 * routine allows callers of cppc_get_perf_ctrs() to know this ahead of time.
1364 *
1365 * Return: true if any of the counters are in PCC regions, false otherwise
1366 */
1367bool cppc_perf_ctrs_in_pcc(void)
1368{
1369	int cpu;
1370
1371	for_each_present_cpu(cpu) {
1372		struct cpc_register_resource *ref_perf_reg;
1373		struct cpc_desc *cpc_desc;
1374
1375		cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1376
1377		if (CPC_IN_PCC(&cpc_desc->cpc_regs[DELIVERED_CTR]) ||
1378		    CPC_IN_PCC(&cpc_desc->cpc_regs[REFERENCE_CTR]) ||
1379		    CPC_IN_PCC(&cpc_desc->cpc_regs[CTR_WRAP_TIME]))
1380			return true;
1381
1382
1383		ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
1384
1385		/*
1386		 * If reference perf register is not supported then we should
1387		 * use the nominal perf value
1388		 */
1389		if (!CPC_SUPPORTED(ref_perf_reg))
1390			ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
1391
1392		if (CPC_IN_PCC(ref_perf_reg))
1393			return true;
1394	}
1395
1396	return false;
1397}
1398EXPORT_SYMBOL_GPL(cppc_perf_ctrs_in_pcc);
1399
1400/**
1401 * cppc_get_perf_ctrs - Read a CPU's performance feedback counters.
1402 * @cpunum: CPU from which to read counters.
1403 * @perf_fb_ctrs: ptr to cppc_perf_fb_ctrs. See cppc_acpi.h
1404 *
1405 * Return: 0 for success with perf_fb_ctrs populated else -ERRNO.
1406 */
1407int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
1408{
1409	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1410	struct cpc_register_resource *delivered_reg, *reference_reg,
1411		*ref_perf_reg, *ctr_wrap_reg;
1412	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1413	struct cppc_pcc_data *pcc_ss_data = NULL;
1414	u64 delivered, reference, ref_perf, ctr_wrap_time;
1415	int ret = 0, regs_in_pcc = 0;
1416
1417	if (!cpc_desc) {
1418		pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1419		return -ENODEV;
1420	}
1421
1422	delivered_reg = &cpc_desc->cpc_regs[DELIVERED_CTR];
1423	reference_reg = &cpc_desc->cpc_regs[REFERENCE_CTR];
1424	ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
1425	ctr_wrap_reg = &cpc_desc->cpc_regs[CTR_WRAP_TIME];
1426
1427	/*
1428	 * If reference perf register is not supported then we should
1429	 * use the nominal perf value
1430	 */
1431	if (!CPC_SUPPORTED(ref_perf_reg))
1432		ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
1433
1434	/* Are any of the regs PCC ?*/
1435	if (CPC_IN_PCC(delivered_reg) || CPC_IN_PCC(reference_reg) ||
1436		CPC_IN_PCC(ctr_wrap_reg) || CPC_IN_PCC(ref_perf_reg)) {
1437		if (pcc_ss_id < 0) {
1438			pr_debug("Invalid pcc_ss_id\n");
1439			return -ENODEV;
1440		}
1441		pcc_ss_data = pcc_data[pcc_ss_id];
1442		down_write(&pcc_ss_data->pcc_lock);
1443		regs_in_pcc = 1;
1444		/* Ring doorbell once to update PCC subspace */
1445		if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
1446			ret = -EIO;
1447			goto out_err;
1448		}
1449	}
1450
1451	cpc_read(cpunum, delivered_reg, &delivered);
1452	cpc_read(cpunum, reference_reg, &reference);
1453	cpc_read(cpunum, ref_perf_reg, &ref_perf);
1454
1455	/*
1456	 * Per spec, if ctr_wrap_time optional register is unsupported, then the
1457	 * performance counters are assumed to never wrap during the lifetime of
1458	 * platform
1459	 */
1460	ctr_wrap_time = (u64)(~((u64)0));
1461	if (CPC_SUPPORTED(ctr_wrap_reg))
1462		cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time);
1463
1464	if (!delivered || !reference ||	!ref_perf) {
1465		ret = -EFAULT;
1466		goto out_err;
1467	}
1468
1469	perf_fb_ctrs->delivered = delivered;
1470	perf_fb_ctrs->reference = reference;
1471	perf_fb_ctrs->reference_perf = ref_perf;
1472	perf_fb_ctrs->wraparound_time = ctr_wrap_time;
1473out_err:
1474	if (regs_in_pcc)
1475		up_write(&pcc_ss_data->pcc_lock);
1476	return ret;
1477}
1478EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
1479
1480/*
1481 * Set Energy Performance Preference Register value through
1482 * Performance Controls Interface
1483 */
1484int cppc_set_epp_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls, bool enable)
1485{
1486	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1487	struct cpc_register_resource *epp_set_reg;
1488	struct cpc_register_resource *auto_sel_reg;
1489	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1490	struct cppc_pcc_data *pcc_ss_data = NULL;
1491	int ret;
1492
1493	if (!cpc_desc) {
1494		pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1495		return -ENODEV;
1496	}
1497
1498	auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];
1499	epp_set_reg = &cpc_desc->cpc_regs[ENERGY_PERF];
1500
1501	if (CPC_IN_PCC(epp_set_reg) || CPC_IN_PCC(auto_sel_reg)) {
1502		if (pcc_ss_id < 0) {
1503			pr_debug("Invalid pcc_ss_id for CPU:%d\n", cpu);
1504			return -ENODEV;
1505		}
1506
1507		if (CPC_SUPPORTED(auto_sel_reg)) {
1508			ret = cpc_write(cpu, auto_sel_reg, enable);
1509			if (ret)
1510				return ret;
1511		}
1512
1513		if (CPC_SUPPORTED(epp_set_reg)) {
1514			ret = cpc_write(cpu, epp_set_reg, perf_ctrls->energy_perf);
1515			if (ret)
1516				return ret;
1517		}
1518
1519		pcc_ss_data = pcc_data[pcc_ss_id];
1520
1521		down_write(&pcc_ss_data->pcc_lock);
1522		/* after writing CPC, transfer the ownership of PCC to platform */
1523		ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
1524		up_write(&pcc_ss_data->pcc_lock);
1525	} else if (osc_cpc_flexible_adr_space_confirmed &&
1526		   CPC_SUPPORTED(epp_set_reg) && CPC_IN_FFH(epp_set_reg)) {
1527		ret = cpc_write(cpu, epp_set_reg, perf_ctrls->energy_perf);
1528	} else {
1529		ret = -ENOTSUPP;
1530		pr_debug("_CPC in PCC and _CPC in FFH are not supported\n");
1531	}
1532
1533	return ret;
1534}
1535EXPORT_SYMBOL_GPL(cppc_set_epp_perf);
1536
1537/**
1538 * cppc_get_auto_sel_caps - Read autonomous selection register.
1539 * @cpunum : CPU from which to read register.
1540 * @perf_caps : struct where autonomous selection register value is updated.
1541 */
1542int cppc_get_auto_sel_caps(int cpunum, struct cppc_perf_caps *perf_caps)
1543{
1544	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
1545	struct cpc_register_resource *auto_sel_reg;
1546	u64  auto_sel;
1547
1548	if (!cpc_desc) {
1549		pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
1550		return -ENODEV;
1551	}
1552
1553	auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];
1554
1555	if (!CPC_SUPPORTED(auto_sel_reg))
1556		pr_warn_once("Autonomous mode is not unsupported!\n");
1557
1558	if (CPC_IN_PCC(auto_sel_reg)) {
1559		int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
1560		struct cppc_pcc_data *pcc_ss_data = NULL;
1561		int ret = 0;
1562
1563		if (pcc_ss_id < 0)
1564			return -ENODEV;
1565
1566		pcc_ss_data = pcc_data[pcc_ss_id];
1567
1568		down_write(&pcc_ss_data->pcc_lock);
1569
1570		if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0) {
1571			cpc_read(cpunum, auto_sel_reg, &auto_sel);
1572			perf_caps->auto_sel = (bool)auto_sel;
1573		} else {
1574			ret = -EIO;
1575		}
1576
1577		up_write(&pcc_ss_data->pcc_lock);
1578
1579		return ret;
1580	}
1581
1582	return 0;
1583}
1584EXPORT_SYMBOL_GPL(cppc_get_auto_sel_caps);
1585
1586/**
1587 * cppc_set_auto_sel - Write autonomous selection register.
1588 * @cpu    : CPU to which to write register.
1589 * @enable : the desired value of autonomous selection resiter to be updated.
1590 */
1591int cppc_set_auto_sel(int cpu, bool enable)
1592{
1593	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1594	struct cpc_register_resource *auto_sel_reg;
1595	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1596	struct cppc_pcc_data *pcc_ss_data = NULL;
1597	int ret = -EINVAL;
1598
1599	if (!cpc_desc) {
1600		pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1601		return -ENODEV;
1602	}
1603
1604	auto_sel_reg = &cpc_desc->cpc_regs[AUTO_SEL_ENABLE];
1605
1606	if (CPC_IN_PCC(auto_sel_reg)) {
1607		if (pcc_ss_id < 0) {
1608			pr_debug("Invalid pcc_ss_id\n");
1609			return -ENODEV;
1610		}
1611
1612		if (CPC_SUPPORTED(auto_sel_reg)) {
1613			ret = cpc_write(cpu, auto_sel_reg, enable);
1614			if (ret)
1615				return ret;
1616		}
1617
1618		pcc_ss_data = pcc_data[pcc_ss_id];
1619
1620		down_write(&pcc_ss_data->pcc_lock);
1621		/* after writing CPC, transfer the ownership of PCC to platform */
1622		ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
1623		up_write(&pcc_ss_data->pcc_lock);
1624	} else {
1625		ret = -ENOTSUPP;
1626		pr_debug("_CPC in PCC is not supported\n");
1627	}
1628
1629	return ret;
1630}
1631EXPORT_SYMBOL_GPL(cppc_set_auto_sel);
1632
1633/**
1634 * cppc_set_enable - Set to enable CPPC on the processor by writing the
1635 * Continuous Performance Control package EnableRegister field.
1636 * @cpu: CPU for which to enable CPPC register.
1637 * @enable: 0 - disable, 1 - enable CPPC feature on the processor.
1638 *
1639 * Return: 0 for success, -ERRNO or -EIO otherwise.
1640 */
1641int cppc_set_enable(int cpu, bool enable)
1642{
1643	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1644	struct cpc_register_resource *enable_reg;
1645	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1646	struct cppc_pcc_data *pcc_ss_data = NULL;
1647	int ret = -EINVAL;
1648
1649	if (!cpc_desc) {
1650		pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1651		return -EINVAL;
1652	}
1653
1654	enable_reg = &cpc_desc->cpc_regs[ENABLE];
1655
1656	if (CPC_IN_PCC(enable_reg)) {
1657
1658		if (pcc_ss_id < 0)
1659			return -EIO;
1660
1661		ret = cpc_write(cpu, enable_reg, enable);
1662		if (ret)
1663			return ret;
1664
1665		pcc_ss_data = pcc_data[pcc_ss_id];
1666
1667		down_write(&pcc_ss_data->pcc_lock);
1668		/* after writing CPC, transfer the ownership of PCC to platfrom */
1669		ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
1670		up_write(&pcc_ss_data->pcc_lock);
1671		return ret;
1672	}
1673
1674	return cpc_write(cpu, enable_reg, enable);
1675}
1676EXPORT_SYMBOL_GPL(cppc_set_enable);
1677
1678/**
1679 * cppc_set_perf - Set a CPU's performance controls.
1680 * @cpu: CPU for which to set performance controls.
1681 * @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
1682 *
1683 * Return: 0 for success, -ERRNO otherwise.
1684 */
1685int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
1686{
1687	struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
1688	struct cpc_register_resource *desired_reg, *min_perf_reg, *max_perf_reg;
1689	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
1690	struct cppc_pcc_data *pcc_ss_data = NULL;
1691	int ret = 0;
1692
1693	if (!cpc_desc) {
1694		pr_debug("No CPC descriptor for CPU:%d\n", cpu);
1695		return -ENODEV;
1696	}
1697
1698	desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
1699	min_perf_reg = &cpc_desc->cpc_regs[MIN_PERF];
1700	max_perf_reg = &cpc_desc->cpc_regs[MAX_PERF];
1701
1702	/*
1703	 * This is Phase-I where we want to write to CPC registers
1704	 * -> We want all CPUs to be able to execute this phase in parallel
1705	 *
1706	 * Since read_lock can be acquired by multiple CPUs simultaneously we
1707	 * achieve that goal here
1708	 */
1709	if (CPC_IN_PCC(desired_reg) || CPC_IN_PCC(min_perf_reg) || CPC_IN_PCC(max_perf_reg)) {
1710		if (pcc_ss_id < 0) {
1711			pr_debug("Invalid pcc_ss_id\n");
1712			return -ENODEV;
1713		}
1714		pcc_ss_data = pcc_data[pcc_ss_id];
1715		down_read(&pcc_ss_data->pcc_lock); /* BEGIN Phase-I */
1716		if (pcc_ss_data->platform_owns_pcc) {
1717			ret = check_pcc_chan(pcc_ss_id, false);
1718			if (ret) {
1719				up_read(&pcc_ss_data->pcc_lock);
1720				return ret;
1721			}
1722		}
1723		/*
1724		 * Update the pending_write to make sure a PCC CMD_READ will not
1725		 * arrive and steal the channel during the switch to write lock
1726		 */
1727		pcc_ss_data->pending_pcc_write_cmd = true;
1728		cpc_desc->write_cmd_id = pcc_ss_data->pcc_write_cnt;
1729		cpc_desc->write_cmd_status = 0;
1730	}
1731
1732	cpc_write(cpu, desired_reg, perf_ctrls->desired_perf);
1733
1734	/*
1735	 * Only write if min_perf and max_perf not zero. Some drivers pass zero
1736	 * value to min and max perf, but they don't mean to set the zero value,
1737	 * they just don't want to write to those registers.
1738	 */
1739	if (perf_ctrls->min_perf)
1740		cpc_write(cpu, min_perf_reg, perf_ctrls->min_perf);
1741	if (perf_ctrls->max_perf)
1742		cpc_write(cpu, max_perf_reg, perf_ctrls->max_perf);
1743
1744	if (CPC_IN_PCC(desired_reg) || CPC_IN_PCC(min_perf_reg) || CPC_IN_PCC(max_perf_reg))
1745		up_read(&pcc_ss_data->pcc_lock);	/* END Phase-I */
1746	/*
1747	 * This is Phase-II where we transfer the ownership of PCC to Platform
1748	 *
1749	 * Short Summary: Basically if we think of a group of cppc_set_perf
1750	 * requests that happened in short overlapping interval. The last CPU to
1751	 * come out of Phase-I will enter Phase-II and ring the doorbell.
1752	 *
1753	 * We have the following requirements for Phase-II:
1754	 *     1. We want to execute Phase-II only when there are no CPUs
1755	 * currently executing in Phase-I
1756	 *     2. Once we start Phase-II we want to avoid all other CPUs from
1757	 * entering Phase-I.
1758	 *     3. We want only one CPU among all those who went through Phase-I
1759	 * to run phase-II
1760	 *
1761	 * If write_trylock fails to get the lock and doesn't transfer the
1762	 * PCC ownership to the platform, then one of the following will be TRUE
1763	 *     1. There is at-least one CPU in Phase-I which will later execute
1764	 * write_trylock, so the CPUs in Phase-I will be responsible for
1765	 * executing the Phase-II.
1766	 *     2. Some other CPU has beaten this CPU to successfully execute the
1767	 * write_trylock and has already acquired the write_lock. We know for a
1768	 * fact it (other CPU acquiring the write_lock) couldn't have happened
1769	 * before this CPU's Phase-I as we held the read_lock.
1770	 *     3. Some other CPU executing pcc CMD_READ has stolen the
1771	 * down_write, in which case, send_pcc_cmd will check for pending
1772	 * CMD_WRITE commands by checking the pending_pcc_write_cmd.
1773	 * So this CPU can be certain that its request will be delivered
1774	 *    So in all cases, this CPU knows that its request will be delivered
1775	 * by another CPU and can return
1776	 *
1777	 * After getting the down_write we still need to check for
1778	 * pending_pcc_write_cmd to take care of the following scenario
1779	 *    The thread running this code could be scheduled out between
1780	 * Phase-I and Phase-II. Before it is scheduled back on, another CPU
1781	 * could have delivered the request to Platform by triggering the
1782	 * doorbell and transferred the ownership of PCC to platform. So this
1783	 * avoids triggering an unnecessary doorbell and more importantly before
1784	 * triggering the doorbell it makes sure that the PCC channel ownership
1785	 * is still with OSPM.
1786	 *   pending_pcc_write_cmd can also be cleared by a different CPU, if
1787	 * there was a pcc CMD_READ waiting on down_write and it steals the lock
1788	 * before the pcc CMD_WRITE is completed. send_pcc_cmd checks for this
1789	 * case during a CMD_READ and if there are pending writes it delivers
1790	 * the write command before servicing the read command
1791	 */
1792	if (CPC_IN_PCC(desired_reg) || CPC_IN_PCC(min_perf_reg) || CPC_IN_PCC(max_perf_reg)) {
1793		if (down_write_trylock(&pcc_ss_data->pcc_lock)) {/* BEGIN Phase-II */
1794			/* Update only if there are pending write commands */
1795			if (pcc_ss_data->pending_pcc_write_cmd)
1796				send_pcc_cmd(pcc_ss_id, CMD_WRITE);
1797			up_write(&pcc_ss_data->pcc_lock);	/* END Phase-II */
1798		} else
1799			/* Wait until pcc_write_cnt is updated by send_pcc_cmd */
1800			wait_event(pcc_ss_data->pcc_write_wait_q,
1801				   cpc_desc->write_cmd_id != pcc_ss_data->pcc_write_cnt);
1802
1803		/* send_pcc_cmd updates the status in case of failure */
1804		ret = cpc_desc->write_cmd_status;
1805	}
1806	return ret;
1807}
1808EXPORT_SYMBOL_GPL(cppc_set_perf);
1809
1810/**
1811 * cppc_get_transition_latency - returns frequency transition latency in ns
1812 * @cpu_num: CPU number for per_cpu().
1813 *
1814 * ACPI CPPC does not explicitly specify how a platform can specify the
1815 * transition latency for performance change requests. The closest we have
1816 * is the timing information from the PCCT tables which provides the info
1817 * on the number and frequency of PCC commands the platform can handle.
1818 *
1819 * If desired_reg is in the SystemMemory or SystemIo ACPI address space,
1820 * then assume there is no latency.
1821 */
1822unsigned int cppc_get_transition_latency(int cpu_num)
1823{
1824	/*
1825	 * Expected transition latency is based on the PCCT timing values
1826	 * Below are definition from ACPI spec:
1827	 * pcc_nominal- Expected latency to process a command, in microseconds
1828	 * pcc_mpar   - The maximum number of periodic requests that the subspace
1829	 *              channel can support, reported in commands per minute. 0
1830	 *              indicates no limitation.
1831	 * pcc_mrtt   - The minimum amount of time that OSPM must wait after the
1832	 *              completion of a command before issuing the next command,
1833	 *              in microseconds.
1834	 */
1835	unsigned int latency_ns = 0;
1836	struct cpc_desc *cpc_desc;
1837	struct cpc_register_resource *desired_reg;
1838	int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu_num);
1839	struct cppc_pcc_data *pcc_ss_data;
1840
1841	cpc_desc = per_cpu(cpc_desc_ptr, cpu_num);
1842	if (!cpc_desc)
1843		return CPUFREQ_ETERNAL;
1844
1845	desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
1846	if (CPC_IN_SYSTEM_MEMORY(desired_reg) || CPC_IN_SYSTEM_IO(desired_reg))
1847		return 0;
1848	else if (!CPC_IN_PCC(desired_reg))
1849		return CPUFREQ_ETERNAL;
1850
1851	if (pcc_ss_id < 0)
1852		return CPUFREQ_ETERNAL;
1853
1854	pcc_ss_data = pcc_data[pcc_ss_id];
1855	if (pcc_ss_data->pcc_mpar)
1856		latency_ns = 60 * (1000 * 1000 * 1000 / pcc_ss_data->pcc_mpar);
1857
1858	latency_ns = max(latency_ns, pcc_ss_data->pcc_nominal * 1000);
1859	latency_ns = max(latency_ns, pcc_ss_data->pcc_mrtt * 1000);
1860
1861	return latency_ns;
1862}
1863EXPORT_SYMBOL_GPL(cppc_get_transition_latency);
1864
1865/* Minimum struct length needed for the DMI processor entry we want */
1866#define DMI_ENTRY_PROCESSOR_MIN_LENGTH	48
1867
1868/* Offset in the DMI processor structure for the max frequency */
1869#define DMI_PROCESSOR_MAX_SPEED		0x14
1870
1871/* Callback function used to retrieve the max frequency from DMI */
1872static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
1873{
1874	const u8 *dmi_data = (const u8 *)dm;
1875	u16 *mhz = (u16 *)private;
1876
1877	if (dm->type == DMI_ENTRY_PROCESSOR &&
1878	    dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
1879		u16 val = (u16)get_unaligned((const u16 *)
1880				(dmi_data + DMI_PROCESSOR_MAX_SPEED));
1881		*mhz = umax(val, *mhz);
1882	}
1883}
1884
1885/* Look up the max frequency in DMI */
1886static u64 cppc_get_dmi_max_khz(void)
1887{
1888	u16 mhz = 0;
1889
1890	dmi_walk(cppc_find_dmi_mhz, &mhz);
1891
1892	/*
1893	 * Real stupid fallback value, just in case there is no
1894	 * actual value set.
1895	 */
1896	mhz = mhz ? mhz : 1;
1897
1898	return KHZ_PER_MHZ * mhz;
1899}
1900
1901/*
1902 * If CPPC lowest_freq and nominal_freq registers are exposed then we can
1903 * use them to convert perf to freq and vice versa. The conversion is
1904 * extrapolated as an affine function passing by the 2 points:
1905 *  - (Low perf, Low freq)
1906 *  - (Nominal perf, Nominal freq)
1907 */
1908unsigned int cppc_perf_to_khz(struct cppc_perf_caps *caps, unsigned int perf)
1909{
1910	s64 retval, offset = 0;
1911	static u64 max_khz;
1912	u64 mul, div;
1913
1914	if (caps->lowest_freq && caps->nominal_freq) {
1915		/* Avoid special case when nominal_freq is equal to lowest_freq */
1916		if (caps->lowest_freq == caps->nominal_freq) {
1917			mul = caps->nominal_freq;
1918			div = caps->nominal_perf;
1919		} else {
1920			mul = caps->nominal_freq - caps->lowest_freq;
1921			div = caps->nominal_perf - caps->lowest_perf;
1922		}
1923		mul *= KHZ_PER_MHZ;
1924		offset = caps->nominal_freq * KHZ_PER_MHZ -
1925			 div64_u64(caps->nominal_perf * mul, div);
1926	} else {
1927		if (!max_khz)
1928			max_khz = cppc_get_dmi_max_khz();
1929		mul = max_khz;
1930		div = caps->highest_perf;
1931	}
1932
1933	retval = offset + div64_u64(perf * mul, div);
1934	if (retval >= 0)
1935		return retval;
1936	return 0;
1937}
1938EXPORT_SYMBOL_GPL(cppc_perf_to_khz);
1939
1940unsigned int cppc_khz_to_perf(struct cppc_perf_caps *caps, unsigned int freq)
1941{
1942	s64 retval, offset = 0;
1943	static u64 max_khz;
1944	u64 mul, div;
1945
1946	if (caps->lowest_freq && caps->nominal_freq) {
1947		/* Avoid special case when nominal_freq is equal to lowest_freq */
1948		if (caps->lowest_freq == caps->nominal_freq) {
1949			mul = caps->nominal_perf;
1950			div = caps->nominal_freq;
1951		} else {
1952			mul = caps->nominal_perf - caps->lowest_perf;
1953			div = caps->nominal_freq - caps->lowest_freq;
1954		}
1955		/*
1956		 * We don't need to convert to kHz for computing offset and can
1957		 * directly use nominal_freq and lowest_freq as the div64_u64
1958		 * will remove the frequency unit.
1959		 */
1960		offset = caps->nominal_perf -
1961			 div64_u64(caps->nominal_freq * mul, div);
1962		/* But we need it for computing the perf level. */
1963		div *= KHZ_PER_MHZ;
1964	} else {
1965		if (!max_khz)
1966			max_khz = cppc_get_dmi_max_khz();
1967		mul = caps->highest_perf;
1968		div = max_khz;
1969	}
1970
1971	retval = offset + div64_u64(freq * mul, div);
1972	if (retval >= 0)
1973		return retval;
1974	return 0;
1975}
1976EXPORT_SYMBOL_GPL(cppc_khz_to_perf);