drivers/perf/arm_cspmu/ampere_cspmu.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Ampere SoC PMU (Performance Monitor Unit)
  *
  * Copyright (c) 2023, Ampere Computing LLC
  */
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/topology.h>

 #include "arm_cspmu.h"

 #define PMAUXR0		0xD80
 #define PMAUXR1		0xD84
 #define PMAUXR2		0xD88
 #define PMAUXR3		0xD8C

 #define to_ampere_cspmu_ctx(cspmu)	((struct ampere_cspmu_ctx *)(cspmu->impl.ctx))

 struct ampere_cspmu_ctx {
 	const char *name;
 	struct attribute **event_attr;
 	struct attribute **format_attr;
 };

 static DEFINE_IDA(mcu_pmu_ida);

 #define SOC_PMU_EVENT_ATTR_EXTRACTOR(_name, _config, _start, _end)        \
 	static inline u32 get_##_name(const struct perf_event *event)     \
 	{                                                                 \
 		return FIELD_GET(GENMASK_ULL(_end, _start),               \
 				 event->attr._config);                    \
 	}                                                                 \

 SOC_PMU_EVENT_ATTR_EXTRACTOR(event, config, 0, 8);
 SOC_PMU_EVENT_ATTR_EXTRACTOR(threshold, config1, 0, 7);
 SOC_PMU_EVENT_ATTR_EXTRACTOR(rank, config1, 8, 23);
 SOC_PMU_EVENT_ATTR_EXTRACTOR(bank, config1, 24, 55);

 static struct attribute *ampereone_mcu_pmu_event_attrs[] = {
 	ARM_CSPMU_EVENT_ATTR(cycle_count,		0x00),
 	ARM_CSPMU_EVENT_ATTR(act_sent,			0x01),
 	ARM_CSPMU_EVENT_ATTR(pre_sent,			0x02),
 	ARM_CSPMU_EVENT_ATTR(rd_sent,			0x03),
 	ARM_CSPMU_EVENT_ATTR(rda_sent,			0x04),
 	ARM_CSPMU_EVENT_ATTR(wr_sent,			0x05),
 	ARM_CSPMU_EVENT_ATTR(wra_sent,			0x06),
 	ARM_CSPMU_EVENT_ATTR(pd_entry_vld,		0x07),
 	ARM_CSPMU_EVENT_ATTR(sref_entry_vld,		0x08),
 	ARM_CSPMU_EVENT_ATTR(prea_sent,			0x09),
 	ARM_CSPMU_EVENT_ATTR(pre_sb_sent,		0x0a),
 	ARM_CSPMU_EVENT_ATTR(ref_sent,			0x0b),
 	ARM_CSPMU_EVENT_ATTR(rfm_sent,			0x0c),
 	ARM_CSPMU_EVENT_ATTR(ref_sb_sent,		0x0d),
 	ARM_CSPMU_EVENT_ATTR(rfm_sb_sent,		0x0e),
 	ARM_CSPMU_EVENT_ATTR(rd_rda_sent,		0x0f),
 	ARM_CSPMU_EVENT_ATTR(wr_wra_sent,		0x10),
 	ARM_CSPMU_EVENT_ATTR(raw_hazard,		0x11),
 	ARM_CSPMU_EVENT_ATTR(war_hazard,		0x12),
 	ARM_CSPMU_EVENT_ATTR(waw_hazard,		0x13),
 	ARM_CSPMU_EVENT_ATTR(rar_hazard,		0x14),
 	ARM_CSPMU_EVENT_ATTR(raw_war_waw_hazard,	0x15),
 	ARM_CSPMU_EVENT_ATTR(hprd_lprd_wr_req_vld,	0x16),
 	ARM_CSPMU_EVENT_ATTR(lprd_req_vld,		0x17),
 	ARM_CSPMU_EVENT_ATTR(hprd_req_vld,		0x18),
 	ARM_CSPMU_EVENT_ATTR(hprd_lprd_req_vld,		0x19),
 	ARM_CSPMU_EVENT_ATTR(prefetch_tgt,		0x1a),
 	ARM_CSPMU_EVENT_ATTR(wr_req_vld,		0x1b),
 	ARM_CSPMU_EVENT_ATTR(partial_wr_req_vld,	0x1c),
 	ARM_CSPMU_EVENT_ATTR(rd_retry,			0x1d),
 	ARM_CSPMU_EVENT_ATTR(wr_retry,			0x1e),
 	ARM_CSPMU_EVENT_ATTR(retry_gnt,			0x1f),
 	ARM_CSPMU_EVENT_ATTR(rank_change,		0x20),
 	ARM_CSPMU_EVENT_ATTR(dir_change,		0x21),
 	ARM_CSPMU_EVENT_ATTR(rank_dir_change,		0x22),
 	ARM_CSPMU_EVENT_ATTR(rank_active,		0x23),
 	ARM_CSPMU_EVENT_ATTR(rank_idle,			0x24),
 	ARM_CSPMU_EVENT_ATTR(rank_pd,			0x25),
 	ARM_CSPMU_EVENT_ATTR(rank_sref,			0x26),
 	ARM_CSPMU_EVENT_ATTR(queue_fill_gt_thresh,	0x27),
 	ARM_CSPMU_EVENT_ATTR(queue_rds_gt_thresh,	0x28),
 	ARM_CSPMU_EVENT_ATTR(queue_wrs_gt_thresh,	0x29),
 	ARM_CSPMU_EVENT_ATTR(phy_updt_complt,		0x2a),
 	ARM_CSPMU_EVENT_ATTR(tz_fail,			0x2b),
 	ARM_CSPMU_EVENT_ATTR(dram_errc,			0x2c),
 	ARM_CSPMU_EVENT_ATTR(dram_errd,			0x2d),
 	ARM_CSPMU_EVENT_ATTR(read_data_return,		0x32),
 	ARM_CSPMU_EVENT_ATTR(chi_wr_data_delta,		0x33),
 	ARM_CSPMU_EVENT_ATTR(zq_start,			0x34),
 	ARM_CSPMU_EVENT_ATTR(zq_latch,			0x35),
 	ARM_CSPMU_EVENT_ATTR(wr_fifo_full,		0x36),
 	ARM_CSPMU_EVENT_ATTR(info_fifo_full,		0x37),
 	ARM_CSPMU_EVENT_ATTR(cmd_fifo_full,		0x38),
 	ARM_CSPMU_EVENT_ATTR(dfi_nop,			0x39),
 	ARM_CSPMU_EVENT_ATTR(dfi_cmd,			0x3a),
 	ARM_CSPMU_EVENT_ATTR(rd_run_len,		0x3b),
 	ARM_CSPMU_EVENT_ATTR(wr_run_len,		0x3c),

 	ARM_CSPMU_EVENT_ATTR(cycles, ARM_CSPMU_EVT_CYCLES_DEFAULT),
 	NULL,
 };

 static struct attribute *ampereone_mcu_format_attrs[] = {
 	ARM_CSPMU_FORMAT_EVENT_ATTR,
 	ARM_CSPMU_FORMAT_ATTR(threshold, "config1:0-7"),
 	ARM_CSPMU_FORMAT_ATTR(rank, "config1:8-23"),
 	ARM_CSPMU_FORMAT_ATTR(bank, "config1:24-55"),
 	NULL,
 };

 static struct attribute **
 ampere_cspmu_get_event_attrs(const struct arm_cspmu *cspmu)
 {
 	const struct ampere_cspmu_ctx *ctx = to_ampere_cspmu_ctx(cspmu);

 	return ctx->event_attr;
 }

 static struct attribute **
 ampere_cspmu_get_format_attrs(const struct arm_cspmu *cspmu)
 {
 	const struct ampere_cspmu_ctx *ctx = to_ampere_cspmu_ctx(cspmu);

 	return ctx->format_attr;
 }

 static const char *
 ampere_cspmu_get_name(const struct arm_cspmu *cspmu)
 {
 	const struct ampere_cspmu_ctx *ctx = to_ampere_cspmu_ctx(cspmu);

 	return ctx->name;
 }

 static u32 ampere_cspmu_event_filter(const struct perf_event *event)
 {
 	/*
 	 * PMEVFILTR or PMCCFILTR aren't used in Ampere SoC PMU but are marked
 	 * as RES0. Make sure, PMCCFILTR is written zero.
 	 */
 	return 0;
 }

 static void ampere_cspmu_set_ev_filter(struct arm_cspmu *cspmu,
 				       struct hw_perf_event *hwc,
 				       u32 filter)
 {
 	struct perf_event *event;
 	unsigned int idx;
 	u32 threshold, rank, bank;

 	/*
 	 * At this point, all the events have the same filter settings.
 	 * Therefore, take the first event and use its configuration.
 	 */
 	idx = find_first_bit(cspmu->hw_events.used_ctrs,
 			     cspmu->cycle_counter_logical_idx);

 	event = cspmu->hw_events.events[idx];

 	threshold	= get_threshold(event);
 	rank		= get_rank(event);
 	bank		= get_bank(event);

 	writel(threshold, cspmu->base0 + PMAUXR0);
 	writel(rank, cspmu->base0 + PMAUXR1);
 	writel(bank, cspmu->base0 + PMAUXR2);
 }

 static int ampere_cspmu_validate_configs(struct perf_event *event,
 					 struct perf_event *event2)
 {
 	if (get_threshold(event) != get_threshold(event2) ||
 	    get_rank(event) != get_rank(event2) ||
 	    get_bank(event) != get_bank(event2))
 		return -EINVAL;

 	return 0;
 }

 static int ampere_cspmu_validate_event(struct arm_cspmu *cspmu,
 				       struct perf_event *new)
 {
 	struct perf_event *curr, *leader = new->group_leader;
 	unsigned int idx;
 	int ret;

 	ret = ampere_cspmu_validate_configs(new, leader);
 	if (ret)
 		return ret;

 	/* We compare the global filter settings to the existing events */
 	idx = find_first_bit(cspmu->hw_events.used_ctrs,
 			     cspmu->cycle_counter_logical_idx);

 	/* This is the first event, thus any configuration is fine */
 	if (idx == cspmu->cycle_counter_logical_idx)
 		return 0;

 	curr = cspmu->hw_events.events[idx];

 	return ampere_cspmu_validate_configs(curr, new);
 }

 static char *ampere_cspmu_format_name(const struct arm_cspmu *cspmu,
 				      const char *name_pattern)
 {
 	struct device *dev = cspmu->dev;
 	int id;

 	id = ida_alloc(&mcu_pmu_ida, GFP_KERNEL);
 	if (id < 0)
 		return ERR_PTR(id);

 	return devm_kasprintf(dev, GFP_KERNEL, name_pattern, id);
 }

 static int ampere_cspmu_init_ops(struct arm_cspmu *cspmu)
 {
 	struct device *dev = cspmu->dev;
 	struct ampere_cspmu_ctx *ctx;
 	struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;

 	ctx = devm_kzalloc(dev, sizeof(struct ampere_cspmu_ctx), GFP_KERNEL);
 	if (!ctx)
 		return -ENOMEM;

 	ctx->event_attr	= ampereone_mcu_pmu_event_attrs;
 	ctx->format_attr = ampereone_mcu_format_attrs;
 	ctx->name = ampere_cspmu_format_name(cspmu, "ampere_mcu_pmu_%d");
 	if (IS_ERR_OR_NULL(ctx->name))
 		return ctx->name ? PTR_ERR(ctx->name) : -ENOMEM;

 	cspmu->impl.ctx = ctx;

 	impl_ops->event_filter		= ampere_cspmu_event_filter;
 	impl_ops->set_ev_filter		= ampere_cspmu_set_ev_filter;
 	impl_ops->validate_event	= ampere_cspmu_validate_event;
 	impl_ops->get_name		= ampere_cspmu_get_name;
 	impl_ops->get_event_attrs	= ampere_cspmu_get_event_attrs;
 	impl_ops->get_format_attrs	= ampere_cspmu_get_format_attrs;

 	return 0;
 }

 /* Match all Ampere Coresight PMU devices */
 static const struct arm_cspmu_impl_match ampere_cspmu_param = {
 	.pmiidr_val	= ARM_CSPMU_IMPL_ID_AMPERE,
 	.module		= THIS_MODULE,
 	.impl_init_ops	= ampere_cspmu_init_ops
 };

 static int __init ampere_cspmu_init(void)
 {
 	int ret;

 	ret = arm_cspmu_impl_register(&ampere_cspmu_param);
 	if (ret)
 		pr_err("ampere_cspmu backend registration error: %d\n", ret);

 	return ret;
 }

 static void __exit ampere_cspmu_exit(void)
 {
 	arm_cspmu_impl_unregister(&ampere_cspmu_param);
 }

 module_init(ampere_cspmu_init);
 module_exit(ampere_cspmu_exit);

 MODULE_DESCRIPTION("Ampere SoC Performance Monitor Driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Ampere SoC PMU (Performance Monitor Unit)
	*
	* Copyright (c) 2023, Ampere Computing LLC
	*/
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/topology.h>

	#include "arm_cspmu.h"

	#define PMAUXR0 0xD80
	#define PMAUXR1 0xD84
	#define PMAUXR2 0xD88
	#define PMAUXR3 0xD8C

	#define to_ampere_cspmu_ctx(cspmu) ((struct ampere_cspmu_ctx *)(cspmu->impl.ctx))

	struct ampere_cspmu_ctx {
	const char *name;
	struct attribute **event_attr;
	struct attribute **format_attr;
	};

	static DEFINE_IDA(mcu_pmu_ida);

	#define SOC_PMU_EVENT_ATTR_EXTRACTOR(_name, _config, _start, _end) \
	static inline u32 get_##_name(const struct perf_event *event) \
	{ \
	return FIELD_GET(GENMASK_ULL(_end, _start), \
	event->attr._config); \
	} \

	SOC_PMU_EVENT_ATTR_EXTRACTOR(event, config, 0, 8);
	SOC_PMU_EVENT_ATTR_EXTRACTOR(threshold, config1, 0, 7);
	SOC_PMU_EVENT_ATTR_EXTRACTOR(rank, config1, 8, 23);
	SOC_PMU_EVENT_ATTR_EXTRACTOR(bank, config1, 24, 55);

	static struct attribute *ampereone_mcu_pmu_event_attrs[] = {
	ARM_CSPMU_EVENT_ATTR(cycle_count, 0x00),
	ARM_CSPMU_EVENT_ATTR(act_sent, 0x01),
	ARM_CSPMU_EVENT_ATTR(pre_sent, 0x02),
	ARM_CSPMU_EVENT_ATTR(rd_sent, 0x03),
	ARM_CSPMU_EVENT_ATTR(rda_sent, 0x04),
	ARM_CSPMU_EVENT_ATTR(wr_sent, 0x05),
	ARM_CSPMU_EVENT_ATTR(wra_sent, 0x06),
	ARM_CSPMU_EVENT_ATTR(pd_entry_vld, 0x07),
	ARM_CSPMU_EVENT_ATTR(sref_entry_vld, 0x08),
	ARM_CSPMU_EVENT_ATTR(prea_sent, 0x09),
	ARM_CSPMU_EVENT_ATTR(pre_sb_sent, 0x0a),
	ARM_CSPMU_EVENT_ATTR(ref_sent, 0x0b),
	ARM_CSPMU_EVENT_ATTR(rfm_sent, 0x0c),
	ARM_CSPMU_EVENT_ATTR(ref_sb_sent, 0x0d),
	ARM_CSPMU_EVENT_ATTR(rfm_sb_sent, 0x0e),
	ARM_CSPMU_EVENT_ATTR(rd_rda_sent, 0x0f),
	ARM_CSPMU_EVENT_ATTR(wr_wra_sent, 0x10),
	ARM_CSPMU_EVENT_ATTR(raw_hazard, 0x11),
	ARM_CSPMU_EVENT_ATTR(war_hazard, 0x12),
	ARM_CSPMU_EVENT_ATTR(waw_hazard, 0x13),
	ARM_CSPMU_EVENT_ATTR(rar_hazard, 0x14),
	ARM_CSPMU_EVENT_ATTR(raw_war_waw_hazard, 0x15),
	ARM_CSPMU_EVENT_ATTR(hprd_lprd_wr_req_vld, 0x16),
	ARM_CSPMU_EVENT_ATTR(lprd_req_vld, 0x17),
	ARM_CSPMU_EVENT_ATTR(hprd_req_vld, 0x18),
	ARM_CSPMU_EVENT_ATTR(hprd_lprd_req_vld, 0x19),
	ARM_CSPMU_EVENT_ATTR(prefetch_tgt, 0x1a),
	ARM_CSPMU_EVENT_ATTR(wr_req_vld, 0x1b),
	ARM_CSPMU_EVENT_ATTR(partial_wr_req_vld, 0x1c),
	ARM_CSPMU_EVENT_ATTR(rd_retry, 0x1d),
	ARM_CSPMU_EVENT_ATTR(wr_retry, 0x1e),
	ARM_CSPMU_EVENT_ATTR(retry_gnt, 0x1f),
	ARM_CSPMU_EVENT_ATTR(rank_change, 0x20),
	ARM_CSPMU_EVENT_ATTR(dir_change, 0x21),
	ARM_CSPMU_EVENT_ATTR(rank_dir_change, 0x22),
	ARM_CSPMU_EVENT_ATTR(rank_active, 0x23),
	ARM_CSPMU_EVENT_ATTR(rank_idle, 0x24),
	ARM_CSPMU_EVENT_ATTR(rank_pd, 0x25),
	ARM_CSPMU_EVENT_ATTR(rank_sref, 0x26),
	ARM_CSPMU_EVENT_ATTR(queue_fill_gt_thresh, 0x27),
	ARM_CSPMU_EVENT_ATTR(queue_rds_gt_thresh, 0x28),
	ARM_CSPMU_EVENT_ATTR(queue_wrs_gt_thresh, 0x29),
	ARM_CSPMU_EVENT_ATTR(phy_updt_complt, 0x2a),
	ARM_CSPMU_EVENT_ATTR(tz_fail, 0x2b),
	ARM_CSPMU_EVENT_ATTR(dram_errc, 0x2c),
	ARM_CSPMU_EVENT_ATTR(dram_errd, 0x2d),
	ARM_CSPMU_EVENT_ATTR(read_data_return, 0x32),
	ARM_CSPMU_EVENT_ATTR(chi_wr_data_delta, 0x33),
	ARM_CSPMU_EVENT_ATTR(zq_start, 0x34),
	ARM_CSPMU_EVENT_ATTR(zq_latch, 0x35),
	ARM_CSPMU_EVENT_ATTR(wr_fifo_full, 0x36),
	ARM_CSPMU_EVENT_ATTR(info_fifo_full, 0x37),
	ARM_CSPMU_EVENT_ATTR(cmd_fifo_full, 0x38),
	ARM_CSPMU_EVENT_ATTR(dfi_nop, 0x39),
	ARM_CSPMU_EVENT_ATTR(dfi_cmd, 0x3a),
	ARM_CSPMU_EVENT_ATTR(rd_run_len, 0x3b),
	ARM_CSPMU_EVENT_ATTR(wr_run_len, 0x3c),

	ARM_CSPMU_EVENT_ATTR(cycles, ARM_CSPMU_EVT_CYCLES_DEFAULT),
	NULL,
	};

	static struct attribute *ampereone_mcu_format_attrs[] = {
	ARM_CSPMU_FORMAT_EVENT_ATTR,
	ARM_CSPMU_FORMAT_ATTR(threshold, "config1:0-7"),
	ARM_CSPMU_FORMAT_ATTR(rank, "config1:8-23"),
	ARM_CSPMU_FORMAT_ATTR(bank, "config1:24-55"),
	NULL,
	};

	static struct attribute **
	ampere_cspmu_get_event_attrs(const struct arm_cspmu *cspmu)
	{
	const struct ampere_cspmu_ctx *ctx = to_ampere_cspmu_ctx(cspmu);

	return ctx->event_attr;
	}

	static struct attribute **
	ampere_cspmu_get_format_attrs(const struct arm_cspmu *cspmu)
	{
	const struct ampere_cspmu_ctx *ctx = to_ampere_cspmu_ctx(cspmu);

	return ctx->format_attr;
	}

	static const char *
	ampere_cspmu_get_name(const struct arm_cspmu *cspmu)
	{
	const struct ampere_cspmu_ctx *ctx = to_ampere_cspmu_ctx(cspmu);

	return ctx->name;
	}

	static u32 ampere_cspmu_event_filter(const struct perf_event *event)
	{
	/*
	* PMEVFILTR or PMCCFILTR aren't used in Ampere SoC PMU but are marked
	* as RES0. Make sure, PMCCFILTR is written zero.
	*/
	return 0;
	}

	static void ampere_cspmu_set_ev_filter(struct arm_cspmu *cspmu,
	struct hw_perf_event *hwc,
	u32 filter)
	{
	struct perf_event *event;
	unsigned int idx;
	u32 threshold, rank, bank;

	/*
	* At this point, all the events have the same filter settings.
	* Therefore, take the first event and use its configuration.
	*/
	idx = find_first_bit(cspmu->hw_events.used_ctrs,
	cspmu->cycle_counter_logical_idx);

	event = cspmu->hw_events.events[idx];

	threshold = get_threshold(event);
	rank = get_rank(event);
	bank = get_bank(event);

	writel(threshold, cspmu->base0 + PMAUXR0);
	writel(rank, cspmu->base0 + PMAUXR1);
	writel(bank, cspmu->base0 + PMAUXR2);
	}

	static int ampere_cspmu_validate_configs(struct perf_event *event,
	struct perf_event *event2)
	{
	if (get_threshold(event) != get_threshold(event2) \|\|
	get_rank(event) != get_rank(event2) \|\|
	get_bank(event) != get_bank(event2))
	return -EINVAL;

	return 0;
	}

	static int ampere_cspmu_validate_event(struct arm_cspmu *cspmu,
	struct perf_event *new)
	{
	struct perf_event curr, leader = new->group_leader;
	unsigned int idx;
	int ret;

	ret = ampere_cspmu_validate_configs(new, leader);
	if (ret)
	return ret;

	/* We compare the global filter settings to the existing events */
	idx = find_first_bit(cspmu->hw_events.used_ctrs,
	cspmu->cycle_counter_logical_idx);

	/* This is the first event, thus any configuration is fine */
	if (idx == cspmu->cycle_counter_logical_idx)
	return 0;

	curr = cspmu->hw_events.events[idx];

	return ampere_cspmu_validate_configs(curr, new);
	}

	static char ampere_cspmu_format_name(const struct arm_cspmu cspmu,
	const char *name_pattern)
	{
	struct device *dev = cspmu->dev;
	int id;

	id = ida_alloc(&mcu_pmu_ida, GFP_KERNEL);
	if (id < 0)
	return ERR_PTR(id);

	return devm_kasprintf(dev, GFP_KERNEL, name_pattern, id);
	}

	static int ampere_cspmu_init_ops(struct arm_cspmu *cspmu)
	{
	struct device *dev = cspmu->dev;
	struct ampere_cspmu_ctx *ctx;
	struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;

	ctx = devm_kzalloc(dev, sizeof(struct ampere_cspmu_ctx), GFP_KERNEL);
	if (!ctx)
	return -ENOMEM;

	ctx->event_attr = ampereone_mcu_pmu_event_attrs;
	ctx->format_attr = ampereone_mcu_format_attrs;
	ctx->name = ampere_cspmu_format_name(cspmu, "ampere_mcu_pmu_%d");
	if (IS_ERR_OR_NULL(ctx->name))
	return ctx->name ? PTR_ERR(ctx->name) : -ENOMEM;

	cspmu->impl.ctx = ctx;

	impl_ops->event_filter = ampere_cspmu_event_filter;
	impl_ops->set_ev_filter = ampere_cspmu_set_ev_filter;
	impl_ops->validate_event = ampere_cspmu_validate_event;
	impl_ops->get_name = ampere_cspmu_get_name;
	impl_ops->get_event_attrs = ampere_cspmu_get_event_attrs;
	impl_ops->get_format_attrs = ampere_cspmu_get_format_attrs;

	return 0;
	}

	/* Match all Ampere Coresight PMU devices */
	static const struct arm_cspmu_impl_match ampere_cspmu_param = {
	.pmiidr_val = ARM_CSPMU_IMPL_ID_AMPERE,
	.module = THIS_MODULE,
	.impl_init_ops = ampere_cspmu_init_ops
	};

	static int __init ampere_cspmu_init(void)
	{
	int ret;

	ret = arm_cspmu_impl_register(&ampere_cspmu_param);
	if (ret)
	pr_err("ampere_cspmu backend registration error: %d\n", ret);

	return ret;
	}

	static void __exit ampere_cspmu_exit(void)
	{
	arm_cspmu_impl_unregister(&ampere_cspmu_param);
	}

	module_init(ampere_cspmu_init);
	module_exit(ampere_cspmu_exit);

	MODULE_DESCRIPTION("Ampere SoC Performance Monitor Driver");
	MODULE_LICENSE("GPL");