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1// SPDX-License-Identifier: GPL-2.02/*3 * ARM CoreSight Architecture PMU driver.4 *5 * This driver adds support for uncore PMU based on ARM CoreSight Performance6 * Monitoring Unit Architecture. The PMU is accessible via MMIO registers and7 * like other uncore PMUs, it does not support process specific events and8 * cannot be used in sampling mode.9 *10 * This code is based on other uncore PMUs like ARM DSU PMU. It provides a11 * generic implementation to operate the PMU according to CoreSight PMU12 * architecture and ACPI ARM PMU table (APMT) documents below:13 *   - ARM CoreSight PMU architecture document number: ARM IHI 0091 A.a-00bet0.14 *   - APMT document number: ARM DEN0117.15 *16 * The user should refer to the vendor technical documentation to get details17 * about the supported events.18 *19 * Copyright (c) 2022-2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved.20 *21 */22 23#include <linux/acpi.h>24#include <linux/cacheinfo.h>25#include <linux/ctype.h>26#include <linux/interrupt.h>27#include <linux/io-64-nonatomic-lo-hi.h>28#include <linux/module.h>29#include <linux/mutex.h>30#include <linux/of.h>31#include <linux/perf_event.h>32#include <linux/platform_device.h>33 34#include "arm_cspmu.h"35 36#define PMUNAME "arm_cspmu"37#define DRVNAME "arm-cs-arch-pmu"38 39#define ARM_CSPMU_CPUMASK_ATTR(_name, _config)			\40	ARM_CSPMU_EXT_ATTR(_name, arm_cspmu_cpumask_show,	\41				(unsigned long)_config)42 43/*44 * CoreSight PMU Arch register offsets.45 */46#define PMEVCNTR_LO					0x047#define PMEVCNTR_HI					0x448#define PMEVTYPER					0x40049#define PMCCFILTR					0x47C50#define PMEVFILTR					0xA0051#define PMCNTENSET					0xC0052#define PMCNTENCLR					0xC2053#define PMINTENSET					0xC4054#define PMINTENCLR					0xC6055#define PMOVSCLR					0xC8056#define PMOVSSET					0xCC057#define PMCFGR						0xE0058#define PMCR						0xE0459#define PMIIDR						0xE0860 61/* PMCFGR register field */62#define PMCFGR_NCG					GENMASK(31, 28)63#define PMCFGR_HDBG					BIT(24)64#define PMCFGR_TRO					BIT(23)65#define PMCFGR_SS					BIT(22)66#define PMCFGR_FZO					BIT(21)67#define PMCFGR_MSI					BIT(20)68#define PMCFGR_UEN					BIT(19)69#define PMCFGR_NA					BIT(17)70#define PMCFGR_EX					BIT(16)71#define PMCFGR_CCD					BIT(15)72#define PMCFGR_CC					BIT(14)73#define PMCFGR_SIZE					GENMASK(13, 8)74#define PMCFGR_N					GENMASK(7, 0)75 76/* PMCR register field */77#define PMCR_TRO					BIT(11)78#define PMCR_HDBG					BIT(10)79#define PMCR_FZO					BIT(9)80#define PMCR_NA						BIT(8)81#define PMCR_DP						BIT(5)82#define PMCR_X						BIT(4)83#define PMCR_D						BIT(3)84#define PMCR_C						BIT(2)85#define PMCR_P						BIT(1)86#define PMCR_E						BIT(0)87 88/* Each SET/CLR register supports up to 32 counters. */89#define ARM_CSPMU_SET_CLR_COUNTER_SHIFT		590#define ARM_CSPMU_SET_CLR_COUNTER_NUM		\91	(1 << ARM_CSPMU_SET_CLR_COUNTER_SHIFT)92 93/* Convert counter idx into SET/CLR register number. */94#define COUNTER_TO_SET_CLR_ID(idx)			\95	(idx >> ARM_CSPMU_SET_CLR_COUNTER_SHIFT)96 97/* Convert counter idx into SET/CLR register bit. */98#define COUNTER_TO_SET_CLR_BIT(idx)			\99	(idx & (ARM_CSPMU_SET_CLR_COUNTER_NUM - 1))100 101#define ARM_CSPMU_ACTIVE_CPU_MASK		0x0102#define ARM_CSPMU_ASSOCIATED_CPU_MASK		0x1103 104/*105 * Maximum poll count for reading counter value using high-low-high sequence.106 */107#define HILOHI_MAX_POLL	1000108 109static unsigned long arm_cspmu_cpuhp_state;110 111static DEFINE_MUTEX(arm_cspmu_lock);112 113static void arm_cspmu_set_ev_filter(struct arm_cspmu *cspmu,114				    struct hw_perf_event *hwc, u32 filter);115 116static struct acpi_apmt_node *arm_cspmu_apmt_node(struct device *dev)117{118	struct acpi_apmt_node **ptr = dev_get_platdata(dev);119 120	return ptr ? *ptr : NULL;121}122 123/*124 * In CoreSight PMU architecture, all of the MMIO registers are 32-bit except125 * counter register. The counter register can be implemented as 32-bit or 64-bit126 * register depending on the value of PMCFGR.SIZE field. For 64-bit access,127 * single-copy 64-bit atomic support is implementation defined. APMT node flag128 * is used to identify if the PMU supports 64-bit single copy atomic. If 64-bit129 * single copy atomic is not supported, the driver treats the register as a pair130 * of 32-bit register.131 */132 133/*134 * Read 64-bit register as a pair of 32-bit registers using hi-lo-hi sequence.135 */136static u64 read_reg64_hilohi(const void __iomem *addr, u32 max_poll_count)137{138	u32 val_lo, val_hi;139	u64 val;140 141	/* Use high-low-high sequence to avoid tearing */142	do {143		if (max_poll_count-- == 0) {144			pr_err("ARM CSPMU: timeout hi-low-high sequence\n");145			return 0;146		}147 148		val_hi = readl(addr + 4);149		val_lo = readl(addr);150	} while (val_hi != readl(addr + 4));151 152	val = (((u64)val_hi << 32) | val_lo);153 154	return val;155}156 157/* Check if cycle counter is supported. */158static inline bool supports_cycle_counter(const struct arm_cspmu *cspmu)159{160	return (cspmu->pmcfgr & PMCFGR_CC);161}162 163/* Get counter size, which is (PMCFGR_SIZE + 1). */164static inline u32 counter_size(const struct arm_cspmu *cspmu)165{166	return FIELD_GET(PMCFGR_SIZE, cspmu->pmcfgr) + 1;167}168 169/* Get counter mask. */170static inline u64 counter_mask(const struct arm_cspmu *cspmu)171{172	return GENMASK_ULL(counter_size(cspmu) - 1, 0);173}174 175/* Check if counter is implemented as 64-bit register. */176static inline bool use_64b_counter_reg(const struct arm_cspmu *cspmu)177{178	return (counter_size(cspmu) > 32);179}180 181ssize_t arm_cspmu_sysfs_event_show(struct device *dev,182				struct device_attribute *attr, char *buf)183{184	struct perf_pmu_events_attr *pmu_attr;185 186	pmu_attr = container_of(attr, typeof(*pmu_attr), attr);187	return sysfs_emit(buf, "event=0x%llx\n", pmu_attr->id);188}189EXPORT_SYMBOL_GPL(arm_cspmu_sysfs_event_show);190 191/* Default event list. */192static struct attribute *arm_cspmu_event_attrs[] = {193	ARM_CSPMU_EVENT_ATTR(cycles, ARM_CSPMU_EVT_CYCLES_DEFAULT),194	NULL,195};196 197static struct attribute **198arm_cspmu_get_event_attrs(const struct arm_cspmu *cspmu)199{200	struct attribute **attrs;201 202	attrs = devm_kmemdup(cspmu->dev, arm_cspmu_event_attrs,203		sizeof(arm_cspmu_event_attrs), GFP_KERNEL);204 205	return attrs;206}207 208static umode_t209arm_cspmu_event_attr_is_visible(struct kobject *kobj,210				struct attribute *attr, int unused)211{212	struct device *dev = kobj_to_dev(kobj);213	struct arm_cspmu *cspmu = to_arm_cspmu(dev_get_drvdata(dev));214	struct perf_pmu_events_attr *eattr;215 216	eattr = container_of(attr, typeof(*eattr), attr.attr);217 218	/* Hide cycle event if not supported */219	if (!supports_cycle_counter(cspmu) &&220	    eattr->id == ARM_CSPMU_EVT_CYCLES_DEFAULT)221		return 0;222 223	return attr->mode;224}225 226static struct attribute *arm_cspmu_format_attrs[] = {227	ARM_CSPMU_FORMAT_EVENT_ATTR,228	ARM_CSPMU_FORMAT_FILTER_ATTR,229	NULL,230};231 232static struct attribute **233arm_cspmu_get_format_attrs(const struct arm_cspmu *cspmu)234{235	struct attribute **attrs;236 237	attrs = devm_kmemdup(cspmu->dev, arm_cspmu_format_attrs,238		sizeof(arm_cspmu_format_attrs), GFP_KERNEL);239 240	return attrs;241}242 243static u32 arm_cspmu_event_type(const struct perf_event *event)244{245	return event->attr.config & ARM_CSPMU_EVENT_MASK;246}247 248static bool arm_cspmu_is_cycle_counter_event(const struct perf_event *event)249{250	return (event->attr.config == ARM_CSPMU_EVT_CYCLES_DEFAULT);251}252 253static u32 arm_cspmu_event_filter(const struct perf_event *event)254{255	return event->attr.config1 & ARM_CSPMU_FILTER_MASK;256}257 258static ssize_t arm_cspmu_identifier_show(struct device *dev,259					 struct device_attribute *attr,260					 char *page)261{262	struct arm_cspmu *cspmu = to_arm_cspmu(dev_get_drvdata(dev));263 264	return sysfs_emit(page, "%s\n", cspmu->identifier);265}266 267static struct device_attribute arm_cspmu_identifier_attr =268	__ATTR(identifier, 0444, arm_cspmu_identifier_show, NULL);269 270static struct attribute *arm_cspmu_identifier_attrs[] = {271	&arm_cspmu_identifier_attr.attr,272	NULL,273};274 275static struct attribute_group arm_cspmu_identifier_attr_group = {276	.attrs = arm_cspmu_identifier_attrs,277};278 279static const char *arm_cspmu_get_identifier(const struct arm_cspmu *cspmu)280{281	const char *identifier =282		devm_kasprintf(cspmu->dev, GFP_KERNEL, "%x",283			       cspmu->impl.pmiidr);284	return identifier;285}286 287static const char *arm_cspmu_type_str[ACPI_APMT_NODE_TYPE_COUNT] = {288	"mc",289	"smmu",290	"pcie",291	"acpi",292	"cache",293};294 295static const char *arm_cspmu_get_name(const struct arm_cspmu *cspmu)296{297	struct device *dev;298	struct acpi_apmt_node *apmt_node;299	u8 pmu_type;300	char *name;301	char acpi_hid_string[ACPI_ID_LEN] = { 0 };302	static atomic_t pmu_idx[ACPI_APMT_NODE_TYPE_COUNT] = { 0 };303 304	dev = cspmu->dev;305	apmt_node = arm_cspmu_apmt_node(dev);306	if (!apmt_node)307		return devm_kasprintf(dev, GFP_KERNEL, PMUNAME "_%u",308				      atomic_fetch_inc(&pmu_idx[0]));309 310	pmu_type = apmt_node->type;311 312	if (pmu_type >= ACPI_APMT_NODE_TYPE_COUNT) {313		dev_err(dev, "unsupported PMU type-%u\n", pmu_type);314		return NULL;315	}316 317	if (pmu_type == ACPI_APMT_NODE_TYPE_ACPI) {318		memcpy(acpi_hid_string,319			&apmt_node->inst_primary,320			sizeof(apmt_node->inst_primary));321		name = devm_kasprintf(dev, GFP_KERNEL, "%s_%s_%s_%u", PMUNAME,322				      arm_cspmu_type_str[pmu_type],323				      acpi_hid_string,324				      apmt_node->inst_secondary);325	} else {326		name = devm_kasprintf(dev, GFP_KERNEL, "%s_%s_%d", PMUNAME,327				      arm_cspmu_type_str[pmu_type],328				      atomic_fetch_inc(&pmu_idx[pmu_type]));329	}330 331	return name;332}333 334static ssize_t arm_cspmu_cpumask_show(struct device *dev,335				      struct device_attribute *attr,336				      char *buf)337{338	struct pmu *pmu = dev_get_drvdata(dev);339	struct arm_cspmu *cspmu = to_arm_cspmu(pmu);340	struct dev_ext_attribute *eattr =341		container_of(attr, struct dev_ext_attribute, attr);342	unsigned long mask_id = (unsigned long)eattr->var;343	const cpumask_t *cpumask;344 345	switch (mask_id) {346	case ARM_CSPMU_ACTIVE_CPU_MASK:347		cpumask = &cspmu->active_cpu;348		break;349	case ARM_CSPMU_ASSOCIATED_CPU_MASK:350		cpumask = &cspmu->associated_cpus;351		break;352	default:353		return 0;354	}355	return cpumap_print_to_pagebuf(true, buf, cpumask);356}357 358static struct attribute *arm_cspmu_cpumask_attrs[] = {359	ARM_CSPMU_CPUMASK_ATTR(cpumask, ARM_CSPMU_ACTIVE_CPU_MASK),360	ARM_CSPMU_CPUMASK_ATTR(associated_cpus, ARM_CSPMU_ASSOCIATED_CPU_MASK),361	NULL,362};363 364static struct attribute_group arm_cspmu_cpumask_attr_group = {365	.attrs = arm_cspmu_cpumask_attrs,366};367 368static struct arm_cspmu_impl_match impl_match[] = {369	{370		.module_name	= "nvidia_cspmu",371		.pmiidr_val	= ARM_CSPMU_IMPL_ID_NVIDIA,372		.pmiidr_mask	= ARM_CSPMU_PMIIDR_IMPLEMENTER,373		.module		= NULL,374		.impl_init_ops	= NULL,375	},376	{377		.module_name	= "ampere_cspmu",378		.pmiidr_val	= ARM_CSPMU_IMPL_ID_AMPERE,379		.pmiidr_mask	= ARM_CSPMU_PMIIDR_IMPLEMENTER,380		.module		= NULL,381		.impl_init_ops	= NULL,382	},383 384	{0}385};386 387static struct arm_cspmu_impl_match *arm_cspmu_impl_match_get(u32 pmiidr)388{389	struct arm_cspmu_impl_match *match = impl_match;390 391	for (; match->pmiidr_val; match++) {392		u32 mask = match->pmiidr_mask;393 394		if ((match->pmiidr_val & mask) == (pmiidr & mask))395			return match;396	}397 398	return NULL;399}400 401#define DEFAULT_IMPL_OP(name)	.name = arm_cspmu_##name402 403static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)404{405	int ret = 0;406	struct acpi_apmt_node *apmt_node = arm_cspmu_apmt_node(cspmu->dev);407	struct arm_cspmu_impl_match *match;408 409	/* Start with a default PMU implementation */410	cspmu->impl.module = THIS_MODULE;411	cspmu->impl.pmiidr = readl(cspmu->base0 + PMIIDR);412	cspmu->impl.ops = (struct arm_cspmu_impl_ops) {413		DEFAULT_IMPL_OP(get_event_attrs),414		DEFAULT_IMPL_OP(get_format_attrs),415		DEFAULT_IMPL_OP(get_identifier),416		DEFAULT_IMPL_OP(get_name),417		DEFAULT_IMPL_OP(is_cycle_counter_event),418		DEFAULT_IMPL_OP(event_type),419		DEFAULT_IMPL_OP(event_filter),420		DEFAULT_IMPL_OP(set_ev_filter),421		DEFAULT_IMPL_OP(event_attr_is_visible),422	};423 424	/* Firmware may override implementer/product ID from PMIIDR */425	if (apmt_node && apmt_node->impl_id)426		cspmu->impl.pmiidr = apmt_node->impl_id;427 428	/* Find implementer specific attribute ops. */429	match = arm_cspmu_impl_match_get(cspmu->impl.pmiidr);430 431	/* Load implementer module and initialize the callbacks. */432	if (match) {433		mutex_lock(&arm_cspmu_lock);434 435		if (match->impl_init_ops) {436			/* Prevent unload until PMU registration is done. */437			if (try_module_get(match->module)) {438				cspmu->impl.module = match->module;439				cspmu->impl.match = match;440				ret = match->impl_init_ops(cspmu);441				if (ret)442					module_put(match->module);443			} else {444				WARN(1, "arm_cspmu failed to get module: %s\n",445					match->module_name);446				ret = -EINVAL;447			}448		} else {449			request_module_nowait(match->module_name);450			ret = -EPROBE_DEFER;451		}452 453		mutex_unlock(&arm_cspmu_lock);454	}455 456	return ret;457}458 459static struct attribute_group *460arm_cspmu_alloc_event_attr_group(struct arm_cspmu *cspmu)461{462	struct attribute_group *event_group;463	struct device *dev = cspmu->dev;464	const struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;465 466	event_group =467		devm_kzalloc(dev, sizeof(struct attribute_group), GFP_KERNEL);468	if (!event_group)469		return NULL;470 471	event_group->name = "events";472	event_group->is_visible = impl_ops->event_attr_is_visible;473	event_group->attrs = impl_ops->get_event_attrs(cspmu);474 475	if (!event_group->attrs)476		return NULL;477 478	return event_group;479}480 481static struct attribute_group *482arm_cspmu_alloc_format_attr_group(struct arm_cspmu *cspmu)483{484	struct attribute_group *format_group;485	struct device *dev = cspmu->dev;486 487	format_group =488		devm_kzalloc(dev, sizeof(struct attribute_group), GFP_KERNEL);489	if (!format_group)490		return NULL;491 492	format_group->name = "format";493	format_group->attrs = cspmu->impl.ops.get_format_attrs(cspmu);494 495	if (!format_group->attrs)496		return NULL;497 498	return format_group;499}500 501static int arm_cspmu_alloc_attr_groups(struct arm_cspmu *cspmu)502{503	const struct attribute_group **attr_groups = cspmu->attr_groups;504	const struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;505 506	cspmu->identifier = impl_ops->get_identifier(cspmu);507	cspmu->name = impl_ops->get_name(cspmu);508 509	if (!cspmu->identifier || !cspmu->name)510		return -ENOMEM;511 512	attr_groups[0] = arm_cspmu_alloc_event_attr_group(cspmu);513	attr_groups[1] = arm_cspmu_alloc_format_attr_group(cspmu);514	attr_groups[2] = &arm_cspmu_identifier_attr_group;515	attr_groups[3] = &arm_cspmu_cpumask_attr_group;516 517	if (!attr_groups[0] || !attr_groups[1])518		return -ENOMEM;519 520	return 0;521}522 523static inline void arm_cspmu_reset_counters(struct arm_cspmu *cspmu)524{525	writel(PMCR_C | PMCR_P, cspmu->base0 + PMCR);526}527 528static inline void arm_cspmu_start_counters(struct arm_cspmu *cspmu)529{530	writel(PMCR_E, cspmu->base0 + PMCR);531}532 533static inline void arm_cspmu_stop_counters(struct arm_cspmu *cspmu)534{535	writel(0, cspmu->base0 + PMCR);536}537 538static void arm_cspmu_enable(struct pmu *pmu)539{540	bool disabled;541	struct arm_cspmu *cspmu = to_arm_cspmu(pmu);542 543	disabled = bitmap_empty(cspmu->hw_events.used_ctrs,544				cspmu->num_logical_ctrs);545 546	if (disabled)547		return;548 549	arm_cspmu_start_counters(cspmu);550}551 552static void arm_cspmu_disable(struct pmu *pmu)553{554	struct arm_cspmu *cspmu = to_arm_cspmu(pmu);555 556	arm_cspmu_stop_counters(cspmu);557}558 559static int arm_cspmu_get_event_idx(struct arm_cspmu_hw_events *hw_events,560				struct perf_event *event)561{562	int idx, ret;563	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);564 565	if (supports_cycle_counter(cspmu)) {566		if (cspmu->impl.ops.is_cycle_counter_event(event)) {567			/* Search for available cycle counter. */568			if (test_and_set_bit(cspmu->cycle_counter_logical_idx,569					     hw_events->used_ctrs))570				return -EAGAIN;571 572			return cspmu->cycle_counter_logical_idx;573		}574 575		/*576		 * Search a regular counter from the used counter bitmap.577		 * The cycle counter divides the bitmap into two parts. Search578		 * the first then second half to exclude the cycle counter bit.579		 */580		idx = find_first_zero_bit(hw_events->used_ctrs,581					  cspmu->cycle_counter_logical_idx);582		if (idx >= cspmu->cycle_counter_logical_idx) {583			idx = find_next_zero_bit(584				hw_events->used_ctrs,585				cspmu->num_logical_ctrs,586				cspmu->cycle_counter_logical_idx + 1);587		}588	} else {589		idx = find_first_zero_bit(hw_events->used_ctrs,590					  cspmu->num_logical_ctrs);591	}592 593	if (idx >= cspmu->num_logical_ctrs)594		return -EAGAIN;595 596	if (cspmu->impl.ops.validate_event) {597		ret = cspmu->impl.ops.validate_event(cspmu, event);598		if (ret)599			return ret;600	}601 602	set_bit(idx, hw_events->used_ctrs);603 604	return idx;605}606 607static bool arm_cspmu_validate_event(struct pmu *pmu,608				 struct arm_cspmu_hw_events *hw_events,609				 struct perf_event *event)610{611	if (is_software_event(event))612		return true;613 614	/* Reject groups spanning multiple HW PMUs. */615	if (event->pmu != pmu)616		return false;617 618	return (arm_cspmu_get_event_idx(hw_events, event) >= 0);619}620 621/*622 * Make sure the group of events can be scheduled at once623 * on the PMU.624 */625static bool arm_cspmu_validate_group(struct perf_event *event)626{627	struct perf_event *sibling, *leader = event->group_leader;628	struct arm_cspmu_hw_events fake_hw_events;629 630	if (event->group_leader == event)631		return true;632 633	memset(&fake_hw_events, 0, sizeof(fake_hw_events));634 635	if (!arm_cspmu_validate_event(event->pmu, &fake_hw_events, leader))636		return false;637 638	for_each_sibling_event(sibling, leader) {639		if (!arm_cspmu_validate_event(event->pmu, &fake_hw_events,640						  sibling))641			return false;642	}643 644	return arm_cspmu_validate_event(event->pmu, &fake_hw_events, event);645}646 647static int arm_cspmu_event_init(struct perf_event *event)648{649	struct arm_cspmu *cspmu;650	struct hw_perf_event *hwc = &event->hw;651 652	cspmu = to_arm_cspmu(event->pmu);653 654	if (event->attr.type != event->pmu->type)655		return -ENOENT;656 657	/*658	 * Following other "uncore" PMUs, we do not support sampling mode or659	 * attach to a task (per-process mode).660	 */661	if (is_sampling_event(event)) {662		dev_dbg(cspmu->pmu.dev,663			"Can't support sampling events\n");664		return -EOPNOTSUPP;665	}666 667	if (event->cpu < 0 || event->attach_state & PERF_ATTACH_TASK) {668		dev_dbg(cspmu->pmu.dev,669			"Can't support per-task counters\n");670		return -EINVAL;671	}672 673	/*674	 * Make sure the CPU assignment is on one of the CPUs associated with675	 * this PMU.676	 */677	if (!cpumask_test_cpu(event->cpu, &cspmu->associated_cpus)) {678		dev_dbg(cspmu->pmu.dev,679			"Requested cpu is not associated with the PMU\n");680		return -EINVAL;681	}682 683	/* Enforce the current active CPU to handle the events in this PMU. */684	event->cpu = cpumask_first(&cspmu->active_cpu);685	if (event->cpu >= nr_cpu_ids)686		return -EINVAL;687 688	if (!arm_cspmu_validate_group(event))689		return -EINVAL;690 691	/*692	 * The logical counter id is tracked with hw_perf_event.extra_reg.idx.693	 * The physical counter id is tracked with hw_perf_event.idx.694	 * We don't assign an index until we actually place the event onto695	 * hardware. Use -1 to signify that we haven't decided where to put it696	 * yet.697	 */698	hwc->idx = -1;699	hwc->extra_reg.idx = -1;700	hwc->config = cspmu->impl.ops.event_type(event);701 702	return 0;703}704 705static inline u32 counter_offset(u32 reg_sz, u32 ctr_idx)706{707	return (PMEVCNTR_LO + (reg_sz * ctr_idx));708}709 710static void arm_cspmu_write_counter(struct perf_event *event, u64 val)711{712	u32 offset;713	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);714 715	if (use_64b_counter_reg(cspmu)) {716		offset = counter_offset(sizeof(u64), event->hw.idx);717 718		if (cspmu->has_atomic_dword)719			writeq(val, cspmu->base1 + offset);720		else721			lo_hi_writeq(val, cspmu->base1 + offset);722	} else {723		offset = counter_offset(sizeof(u32), event->hw.idx);724 725		writel(lower_32_bits(val), cspmu->base1 + offset);726	}727}728 729static u64 arm_cspmu_read_counter(struct perf_event *event)730{731	u32 offset;732	const void __iomem *counter_addr;733	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);734 735	if (use_64b_counter_reg(cspmu)) {736		offset = counter_offset(sizeof(u64), event->hw.idx);737		counter_addr = cspmu->base1 + offset;738 739		return cspmu->has_atomic_dword ?740			       readq(counter_addr) :741			       read_reg64_hilohi(counter_addr, HILOHI_MAX_POLL);742	}743 744	offset = counter_offset(sizeof(u32), event->hw.idx);745	return readl(cspmu->base1 + offset);746}747 748/*749 * arm_cspmu_set_event_period: Set the period for the counter.750 *751 * To handle cases of extreme interrupt latency, we program752 * the counter with half of the max count for the counters.753 */754static void arm_cspmu_set_event_period(struct perf_event *event)755{756	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);757	u64 val = counter_mask(cspmu) >> 1ULL;758 759	local64_set(&event->hw.prev_count, val);760	arm_cspmu_write_counter(event, val);761}762 763static void arm_cspmu_enable_counter(struct arm_cspmu *cspmu, int idx)764{765	u32 reg_id, reg_bit, inten_off, cnten_off;766 767	reg_id = COUNTER_TO_SET_CLR_ID(idx);768	reg_bit = COUNTER_TO_SET_CLR_BIT(idx);769 770	inten_off = PMINTENSET + (4 * reg_id);771	cnten_off = PMCNTENSET + (4 * reg_id);772 773	writel(BIT(reg_bit), cspmu->base0 + inten_off);774	writel(BIT(reg_bit), cspmu->base0 + cnten_off);775}776 777static void arm_cspmu_disable_counter(struct arm_cspmu *cspmu, int idx)778{779	u32 reg_id, reg_bit, inten_off, cnten_off;780 781	reg_id = COUNTER_TO_SET_CLR_ID(idx);782	reg_bit = COUNTER_TO_SET_CLR_BIT(idx);783 784	inten_off = PMINTENCLR + (4 * reg_id);785	cnten_off = PMCNTENCLR + (4 * reg_id);786 787	writel(BIT(reg_bit), cspmu->base0 + cnten_off);788	writel(BIT(reg_bit), cspmu->base0 + inten_off);789}790 791static void arm_cspmu_event_update(struct perf_event *event)792{793	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);794	struct hw_perf_event *hwc = &event->hw;795	u64 delta, prev, now;796 797	do {798		prev = local64_read(&hwc->prev_count);799		now = arm_cspmu_read_counter(event);800	} while (local64_cmpxchg(&hwc->prev_count, prev, now) != prev);801 802	delta = (now - prev) & counter_mask(cspmu);803	local64_add(delta, &event->count);804}805 806static inline void arm_cspmu_set_event(struct arm_cspmu *cspmu,807					struct hw_perf_event *hwc)808{809	u32 offset = PMEVTYPER + (4 * hwc->idx);810 811	writel(hwc->config, cspmu->base0 + offset);812}813 814static void arm_cspmu_set_ev_filter(struct arm_cspmu *cspmu,815					struct hw_perf_event *hwc,816					u32 filter)817{818	u32 offset = PMEVFILTR + (4 * hwc->idx);819 820	writel(filter, cspmu->base0 + offset);821}822 823static inline void arm_cspmu_set_cc_filter(struct arm_cspmu *cspmu, u32 filter)824{825	u32 offset = PMCCFILTR;826 827	writel(filter, cspmu->base0 + offset);828}829 830static void arm_cspmu_start(struct perf_event *event, int pmu_flags)831{832	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);833	struct hw_perf_event *hwc = &event->hw;834	u32 filter;835 836	/* We always reprogram the counter */837	if (pmu_flags & PERF_EF_RELOAD)838		WARN_ON(!(hwc->state & PERF_HES_UPTODATE));839 840	arm_cspmu_set_event_period(event);841 842	filter = cspmu->impl.ops.event_filter(event);843 844	if (event->hw.extra_reg.idx == cspmu->cycle_counter_logical_idx) {845		arm_cspmu_set_cc_filter(cspmu, filter);846	} else {847		arm_cspmu_set_event(cspmu, hwc);848		cspmu->impl.ops.set_ev_filter(cspmu, hwc, filter);849	}850 851	hwc->state = 0;852 853	arm_cspmu_enable_counter(cspmu, hwc->idx);854}855 856static void arm_cspmu_stop(struct perf_event *event, int pmu_flags)857{858	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);859	struct hw_perf_event *hwc = &event->hw;860 861	if (hwc->state & PERF_HES_STOPPED)862		return;863 864	arm_cspmu_disable_counter(cspmu, hwc->idx);865	arm_cspmu_event_update(event);866 867	hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;868}869 870static inline u32 to_phys_idx(struct arm_cspmu *cspmu, u32 idx)871{872	return (idx == cspmu->cycle_counter_logical_idx) ?873		ARM_CSPMU_CYCLE_CNTR_IDX : idx;874}875 876static int arm_cspmu_add(struct perf_event *event, int flags)877{878	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);879	struct arm_cspmu_hw_events *hw_events = &cspmu->hw_events;880	struct hw_perf_event *hwc = &event->hw;881	int idx;882 883	if (WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(),884					   &cspmu->associated_cpus)))885		return -ENOENT;886 887	idx = arm_cspmu_get_event_idx(hw_events, event);888	if (idx < 0)889		return idx;890 891	hw_events->events[idx] = event;892	hwc->idx = to_phys_idx(cspmu, idx);893	hwc->extra_reg.idx = idx;894	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;895 896	if (flags & PERF_EF_START)897		arm_cspmu_start(event, PERF_EF_RELOAD);898 899	/* Propagate changes to the userspace mapping. */900	perf_event_update_userpage(event);901 902	return 0;903}904 905static void arm_cspmu_del(struct perf_event *event, int flags)906{907	struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);908	struct arm_cspmu_hw_events *hw_events = &cspmu->hw_events;909	struct hw_perf_event *hwc = &event->hw;910	int idx = hwc->extra_reg.idx;911 912	arm_cspmu_stop(event, PERF_EF_UPDATE);913 914	hw_events->events[idx] = NULL;915 916	clear_bit(idx, hw_events->used_ctrs);917 918	perf_event_update_userpage(event);919}920 921static void arm_cspmu_read(struct perf_event *event)922{923	arm_cspmu_event_update(event);924}925 926static struct arm_cspmu *arm_cspmu_alloc(struct platform_device *pdev)927{928	struct acpi_apmt_node *apmt_node;929	struct arm_cspmu *cspmu;930	struct device *dev = &pdev->dev;931 932	cspmu = devm_kzalloc(dev, sizeof(*cspmu), GFP_KERNEL);933	if (!cspmu)934		return NULL;935 936	cspmu->dev = dev;937	platform_set_drvdata(pdev, cspmu);938 939	apmt_node = arm_cspmu_apmt_node(dev);940	if (apmt_node) {941		cspmu->has_atomic_dword = apmt_node->flags & ACPI_APMT_FLAGS_ATOMIC;942	} else {943		u32 width = 0;944 945		device_property_read_u32(dev, "reg-io-width", &width);946		cspmu->has_atomic_dword = (width == 8);947	}948 949	return cspmu;950}951 952static int arm_cspmu_init_mmio(struct arm_cspmu *cspmu)953{954	struct device *dev;955	struct platform_device *pdev;956 957	dev = cspmu->dev;958	pdev = to_platform_device(dev);959 960	/* Base address for page 0. */961	cspmu->base0 = devm_platform_ioremap_resource(pdev, 0);962	if (IS_ERR(cspmu->base0)) {963		dev_err(dev, "ioremap failed for page-0 resource\n");964		return PTR_ERR(cspmu->base0);965	}966 967	/* Base address for page 1 if supported. Otherwise point to page 0. */968	cspmu->base1 = cspmu->base0;969	if (platform_get_resource(pdev, IORESOURCE_MEM, 1)) {970		cspmu->base1 = devm_platform_ioremap_resource(pdev, 1);971		if (IS_ERR(cspmu->base1)) {972			dev_err(dev, "ioremap failed for page-1 resource\n");973			return PTR_ERR(cspmu->base1);974		}975	}976 977	cspmu->pmcfgr = readl(cspmu->base0 + PMCFGR);978 979	cspmu->num_logical_ctrs = FIELD_GET(PMCFGR_N, cspmu->pmcfgr) + 1;980 981	cspmu->cycle_counter_logical_idx = ARM_CSPMU_MAX_HW_CNTRS;982 983	if (supports_cycle_counter(cspmu)) {984		/*985		 * The last logical counter is mapped to cycle counter if986		 * there is a gap between regular and cycle counter. Otherwise,987		 * logical and physical have 1-to-1 mapping.988		 */989		cspmu->cycle_counter_logical_idx =990			(cspmu->num_logical_ctrs <= ARM_CSPMU_CYCLE_CNTR_IDX) ?991				cspmu->num_logical_ctrs - 1 :992				ARM_CSPMU_CYCLE_CNTR_IDX;993	}994 995	cspmu->num_set_clr_reg =996		DIV_ROUND_UP(cspmu->num_logical_ctrs,997				ARM_CSPMU_SET_CLR_COUNTER_NUM);998 999	cspmu->hw_events.events =1000		devm_kcalloc(dev, cspmu->num_logical_ctrs,1001			     sizeof(*cspmu->hw_events.events), GFP_KERNEL);1002 1003	if (!cspmu->hw_events.events)1004		return -ENOMEM;1005 1006	return 0;1007}1008 1009static inline int arm_cspmu_get_reset_overflow(struct arm_cspmu *cspmu,1010					       u32 *pmovs)1011{1012	int i;1013	u32 pmovclr_offset = PMOVSCLR;1014	u32 has_overflowed = 0;1015 1016	for (i = 0; i < cspmu->num_set_clr_reg; ++i) {1017		pmovs[i] = readl(cspmu->base1 + pmovclr_offset);1018		has_overflowed |= pmovs[i];1019		writel(pmovs[i], cspmu->base1 + pmovclr_offset);1020		pmovclr_offset += sizeof(u32);1021	}1022 1023	return has_overflowed != 0;1024}1025 1026static irqreturn_t arm_cspmu_handle_irq(int irq_num, void *dev)1027{1028	int idx, has_overflowed;1029	struct perf_event *event;1030	struct arm_cspmu *cspmu = dev;1031	DECLARE_BITMAP(pmovs, ARM_CSPMU_MAX_HW_CNTRS);1032	bool handled = false;1033 1034	arm_cspmu_stop_counters(cspmu);1035 1036	has_overflowed = arm_cspmu_get_reset_overflow(cspmu, (u32 *)pmovs);1037	if (!has_overflowed)1038		goto done;1039 1040	for_each_set_bit(idx, cspmu->hw_events.used_ctrs,1041			cspmu->num_logical_ctrs) {1042		event = cspmu->hw_events.events[idx];1043 1044		if (!event)1045			continue;1046 1047		if (!test_bit(event->hw.idx, pmovs))1048			continue;1049 1050		arm_cspmu_event_update(event);1051		arm_cspmu_set_event_period(event);1052 1053		handled = true;1054	}1055 1056done:1057	arm_cspmu_start_counters(cspmu);1058	return IRQ_RETVAL(handled);1059}1060 1061static int arm_cspmu_request_irq(struct arm_cspmu *cspmu)1062{1063	int irq, ret;1064	struct device *dev;1065	struct platform_device *pdev;1066 1067	dev = cspmu->dev;1068	pdev = to_platform_device(dev);1069 1070	/* Skip IRQ request if the PMU does not support overflow interrupt. */1071	irq = platform_get_irq_optional(pdev, 0);1072	if (irq < 0)1073		return irq == -ENXIO ? 0 : irq;1074 1075	ret = devm_request_irq(dev, irq, arm_cspmu_handle_irq,1076			       IRQF_NOBALANCING | IRQF_NO_THREAD, dev_name(dev),1077			       cspmu);1078	if (ret) {1079		dev_err(dev, "Could not request IRQ %d\n", irq);1080		return ret;1081	}1082 1083	cspmu->irq = irq;1084 1085	return 0;1086}1087 1088#if defined(CONFIG_ACPI) && defined(CONFIG_ARM64)1089#include <acpi/processor.h>1090 1091static inline int arm_cspmu_find_cpu_container(int cpu, u32 container_uid)1092{1093	struct device *cpu_dev;1094	struct acpi_device *acpi_dev;1095 1096	cpu_dev = get_cpu_device(cpu);1097	if (!cpu_dev)1098		return -ENODEV;1099 1100	acpi_dev = ACPI_COMPANION(cpu_dev);1101	while (acpi_dev) {1102		if (acpi_dev_hid_uid_match(acpi_dev, ACPI_PROCESSOR_CONTAINER_HID, container_uid))1103			return 0;1104 1105		acpi_dev = acpi_dev_parent(acpi_dev);1106	}1107 1108	return -ENODEV;1109}1110 1111static int arm_cspmu_acpi_get_cpus(struct arm_cspmu *cspmu)1112{1113	struct acpi_apmt_node *apmt_node;1114	int affinity_flag;1115	int cpu;1116 1117	apmt_node = arm_cspmu_apmt_node(cspmu->dev);1118	affinity_flag = apmt_node->flags & ACPI_APMT_FLAGS_AFFINITY;1119 1120	if (affinity_flag == ACPI_APMT_FLAGS_AFFINITY_PROC) {1121		for_each_possible_cpu(cpu) {1122			if (apmt_node->proc_affinity ==1123			    get_acpi_id_for_cpu(cpu)) {1124				cpumask_set_cpu(cpu, &cspmu->associated_cpus);1125				break;1126			}1127		}1128	} else {1129		for_each_possible_cpu(cpu) {1130			if (arm_cspmu_find_cpu_container(1131				    cpu, apmt_node->proc_affinity))1132				continue;1133 1134			cpumask_set_cpu(cpu, &cspmu->associated_cpus);1135		}1136	}1137 1138	return 0;1139}1140#else1141static int arm_cspmu_acpi_get_cpus(struct arm_cspmu *cspmu)1142{1143	return -ENODEV;1144}1145#endif1146 1147static int arm_cspmu_of_get_cpus(struct arm_cspmu *cspmu)1148{1149	struct of_phandle_iterator it;1150	int ret, cpu;1151 1152	of_for_each_phandle(&it, ret, dev_of_node(cspmu->dev), "cpus", NULL, 0) {1153		cpu = of_cpu_node_to_id(it.node);1154		if (cpu < 0)1155			continue;1156		cpumask_set_cpu(cpu, &cspmu->associated_cpus);1157	}1158	return ret == -ENOENT ? 0 : ret;1159}1160 1161static int arm_cspmu_get_cpus(struct arm_cspmu *cspmu)1162{1163	int ret = 0;1164 1165	if (arm_cspmu_apmt_node(cspmu->dev))1166		ret = arm_cspmu_acpi_get_cpus(cspmu);1167	else if (device_property_present(cspmu->dev, "cpus"))1168		ret = arm_cspmu_of_get_cpus(cspmu);1169	else1170		cpumask_copy(&cspmu->associated_cpus, cpu_possible_mask);1171 1172	if (!ret && cpumask_empty(&cspmu->associated_cpus)) {1173		dev_dbg(cspmu->dev, "No cpu associated with the PMU\n");1174		ret = -ENODEV;1175	}1176	return ret;1177}1178 1179static int arm_cspmu_register_pmu(struct arm_cspmu *cspmu)1180{1181	int ret, capabilities;1182 1183	ret = arm_cspmu_alloc_attr_groups(cspmu);1184	if (ret)1185		return ret;1186 1187	ret = cpuhp_state_add_instance(arm_cspmu_cpuhp_state,1188				       &cspmu->cpuhp_node);1189	if (ret)1190		return ret;1191 1192	capabilities = PERF_PMU_CAP_NO_EXCLUDE;1193	if (cspmu->irq == 0)1194		capabilities |= PERF_PMU_CAP_NO_INTERRUPT;1195 1196	cspmu->pmu = (struct pmu){1197		.task_ctx_nr	= perf_invalid_context,1198		.module		= cspmu->impl.module,1199		.parent		= cspmu->dev,1200		.pmu_enable	= arm_cspmu_enable,1201		.pmu_disable	= arm_cspmu_disable,1202		.event_init	= arm_cspmu_event_init,1203		.add		= arm_cspmu_add,1204		.del		= arm_cspmu_del,1205		.start		= arm_cspmu_start,1206		.stop		= arm_cspmu_stop,1207		.read		= arm_cspmu_read,1208		.attr_groups	= cspmu->attr_groups,1209		.capabilities	= capabilities,1210	};1211 1212	/* Hardware counter init */1213	arm_cspmu_reset_counters(cspmu);1214 1215	ret = perf_pmu_register(&cspmu->pmu, cspmu->name, -1);1216	if (ret) {1217		cpuhp_state_remove_instance(arm_cspmu_cpuhp_state,1218					    &cspmu->cpuhp_node);1219	}1220 1221	return ret;1222}1223 1224static int arm_cspmu_device_probe(struct platform_device *pdev)1225{1226	int ret;1227	struct arm_cspmu *cspmu;1228 1229	cspmu = arm_cspmu_alloc(pdev);1230	if (!cspmu)1231		return -ENOMEM;1232 1233	ret = arm_cspmu_init_mmio(cspmu);1234	if (ret)1235		return ret;1236 1237	ret = arm_cspmu_request_irq(cspmu);1238	if (ret)1239		return ret;1240 1241	ret = arm_cspmu_get_cpus(cspmu);1242	if (ret)1243		return ret;1244 1245	ret = arm_cspmu_init_impl_ops(cspmu);1246	if (ret)1247		return ret;1248 1249	ret = arm_cspmu_register_pmu(cspmu);1250 1251	/* Matches arm_cspmu_init_impl_ops() above. */1252	if (cspmu->impl.module != THIS_MODULE)1253		module_put(cspmu->impl.module);1254 1255	return ret;1256}1257 1258static void arm_cspmu_device_remove(struct platform_device *pdev)1259{1260	struct arm_cspmu *cspmu = platform_get_drvdata(pdev);1261 1262	perf_pmu_unregister(&cspmu->pmu);1263	cpuhp_state_remove_instance(arm_cspmu_cpuhp_state, &cspmu->cpuhp_node);1264}1265 1266static const struct platform_device_id arm_cspmu_id[] = {1267	{DRVNAME, 0},1268	{ },1269};1270MODULE_DEVICE_TABLE(platform, arm_cspmu_id);1271 1272static const struct of_device_id arm_cspmu_of_match[] = {1273	{ .compatible = "arm,coresight-pmu" },1274	{}1275};1276MODULE_DEVICE_TABLE(of, arm_cspmu_of_match);1277 1278static struct platform_driver arm_cspmu_driver = {1279	.driver = {1280		.name = DRVNAME,1281		.of_match_table = arm_cspmu_of_match,1282		.suppress_bind_attrs = true,1283	},1284	.probe = arm_cspmu_device_probe,1285	.remove_new = arm_cspmu_device_remove,1286	.id_table = arm_cspmu_id,1287};1288 1289static void arm_cspmu_set_active_cpu(int cpu, struct arm_cspmu *cspmu)1290{1291	cpumask_set_cpu(cpu, &cspmu->active_cpu);1292	if (cspmu->irq)1293		WARN_ON(irq_set_affinity(cspmu->irq, &cspmu->active_cpu));1294}1295 1296static int arm_cspmu_cpu_online(unsigned int cpu, struct hlist_node *node)1297{1298	struct arm_cspmu *cspmu =1299		hlist_entry_safe(node, struct arm_cspmu, cpuhp_node);1300 1301	if (!cpumask_test_cpu(cpu, &cspmu->associated_cpus))1302		return 0;1303 1304	/* If the PMU is already managed, there is nothing to do */1305	if (!cpumask_empty(&cspmu->active_cpu))1306		return 0;1307 1308	/* Use this CPU for event counting */1309	arm_cspmu_set_active_cpu(cpu, cspmu);1310 1311	return 0;1312}1313 1314static int arm_cspmu_cpu_teardown(unsigned int cpu, struct hlist_node *node)1315{1316	unsigned int dst;1317 1318	struct arm_cspmu *cspmu =1319		hlist_entry_safe(node, struct arm_cspmu, cpuhp_node);1320 1321	/* Nothing to do if this CPU doesn't own the PMU */1322	if (!cpumask_test_and_clear_cpu(cpu, &cspmu->active_cpu))1323		return 0;1324 1325	/* Choose a new CPU to migrate ownership of the PMU to */1326	dst = cpumask_any_and_but(&cspmu->associated_cpus,1327				  cpu_online_mask, cpu);1328	if (dst >= nr_cpu_ids)1329		return 0;1330 1331	/* Use this CPU for event counting */1332	perf_pmu_migrate_context(&cspmu->pmu, cpu, dst);1333	arm_cspmu_set_active_cpu(dst, cspmu);1334 1335	return 0;1336}1337 1338static int __init arm_cspmu_init(void)1339{1340	int ret;1341 1342	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,1343					"perf/arm/cspmu:online",1344					arm_cspmu_cpu_online,1345					arm_cspmu_cpu_teardown);1346	if (ret < 0)1347		return ret;1348	arm_cspmu_cpuhp_state = ret;1349	return platform_driver_register(&arm_cspmu_driver);1350}1351 1352static void __exit arm_cspmu_exit(void)1353{1354	platform_driver_unregister(&arm_cspmu_driver);1355	cpuhp_remove_multi_state(arm_cspmu_cpuhp_state);1356}1357 1358int arm_cspmu_impl_register(const struct arm_cspmu_impl_match *impl_match)1359{1360	struct arm_cspmu_impl_match *match;1361	int ret = 0;1362 1363	match = arm_cspmu_impl_match_get(impl_match->pmiidr_val);1364 1365	if (match) {1366		mutex_lock(&arm_cspmu_lock);1367 1368		if (!match->impl_init_ops) {1369			match->module = impl_match->module;1370			match->impl_init_ops = impl_match->impl_init_ops;1371		} else {1372			/* Broken match table may contain non-unique entries */1373			WARN(1, "arm_cspmu backend already registered for module: %s, pmiidr: 0x%x, mask: 0x%x\n",1374				match->module_name,1375				match->pmiidr_val,1376				match->pmiidr_mask);1377 1378			ret = -EINVAL;1379		}1380 1381		mutex_unlock(&arm_cspmu_lock);1382 1383		if (!ret)1384			ret = driver_attach(&arm_cspmu_driver.driver);1385	} else {1386		pr_err("arm_cspmu reg failed, unable to find a match for pmiidr: 0x%x\n",1387			impl_match->pmiidr_val);1388 1389		ret = -EINVAL;1390	}1391 1392	return ret;1393}1394EXPORT_SYMBOL_GPL(arm_cspmu_impl_register);1395 1396static int arm_cspmu_match_device(struct device *dev, const void *match)1397{1398	struct arm_cspmu *cspmu = platform_get_drvdata(to_platform_device(dev));1399 1400	return (cspmu && cspmu->impl.match == match) ? 1 : 0;1401}1402 1403void arm_cspmu_impl_unregister(const struct arm_cspmu_impl_match *impl_match)1404{1405	struct device *dev;1406	struct arm_cspmu_impl_match *match;1407 1408	match = arm_cspmu_impl_match_get(impl_match->pmiidr_val);1409 1410	if (WARN_ON(!match))1411		return;1412 1413	/* Unbind the driver from all matching backend devices. */1414	while ((dev = driver_find_device(&arm_cspmu_driver.driver, NULL,1415			match, arm_cspmu_match_device)))1416		device_release_driver(dev);1417 1418	mutex_lock(&arm_cspmu_lock);1419 1420	match->module = NULL;1421	match->impl_init_ops = NULL;1422 1423	mutex_unlock(&arm_cspmu_lock);1424}1425EXPORT_SYMBOL_GPL(arm_cspmu_impl_unregister);1426 1427module_init(arm_cspmu_init);1428module_exit(arm_cspmu_exit);1429 1430MODULE_DESCRIPTION("ARM CoreSight Architecture Performance Monitor Driver");1431MODULE_LICENSE("GPL v2");1432