Message-Id: <1472576493-26382-3-git-send-email-nleeder@codeaurora.org>
Date:   Tue, 30 Aug 2016 13:01:33 -0400
From:   Neil Leeder <nleeder@...eaurora.org>
To:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Mark Rutland <mark.rutland@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Mark Langsdorf <mlangsdo@...hat.com>,
        Mark Salter <msalter@...hat.com>, Jon Masters <jcm@...hat.com>,
        Timur Tabi <timur@...eaurora.org>, cov@...eaurora.org,
        nleeder@...eaurora.org
Subject: [PATCH v4 2/2] soc: qcom: add l2 cache perf events driver

Adds perf events support for L2 cache PMU.

The L2 cache PMU driver is named 'l2cache_0' and can be used
with perf events to profile L2 events such as cache hits
and misses.

Signed-off-by: Neil Leeder <nleeder@...eaurora.org>
---
 drivers/soc/qcom/Kconfig               |  10 +
 drivers/soc/qcom/Makefile              |   1 +
 drivers/soc/qcom/perf_event_l2.c       | 855 +++++++++++++++++++++++++++++++++
 include/linux/cpuhotplug.h             |   1 +
 include/linux/soc/qcom/perf_event_l2.h |  79 +++
 5 files changed, 946 insertions(+)
 create mode 100644 drivers/soc/qcom/perf_event_l2.c
 create mode 100644 include/linux/soc/qcom/perf_event_l2.h

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index ddd6b71..7e71d8d 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -16,6 +16,16 @@ config QCOM_L2_ACCESSORS
 	  Provides support for accessing registers in the L2 cache
 	  for Qualcomm Technologies ARM64 chips.
 
+config QCOM_PERF_EVENTS_L2
+	bool "Qualcomm Technologies L2-cache perf events"
+	depends on ARCH_QCOM && ARM64 && HW_PERF_EVENTS && ACPI
+	select QCOM_L2_ACCESSORS
+	  help
+	  Provides support for the L2 cache performance monitor unit (PMU)
+	  in Qualcomm Technologies processors.
+	  Adds the L2 cache PMU into the perf events subsystem for
+	  monitoring L2 cache events.
+
 config QCOM_PM
 	bool "Qualcomm Power Management"
 	depends on ARCH_QCOM && !ARM64
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 6ef29b9..c8e89ca9 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -1,5 +1,6 @@
 obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
 obj-$(CONFIG_QCOM_L2_ACCESSORS) += l2-accessors.o
+obj-$(CONFIG_QCOM_PERF_EVENTS_L2)	+= perf_event_l2.o
 obj-$(CONFIG_QCOM_PM)	+=	spm.o
 obj-$(CONFIG_QCOM_SMD) +=	smd.o
 obj-$(CONFIG_QCOM_SMD_RPM)	+= smd-rpm.o
diff --git a/drivers/soc/qcom/perf_event_l2.c b/drivers/soc/qcom/perf_event_l2.c
new file mode 100644
index 0000000..5c13e87
--- /dev/null
+++ b/drivers/soc/qcom/perf_event_l2.c
@@ -0,0 +1,855 @@
+/* Copyright (c) 2015,2016 The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#define pr_fmt(fmt) "l2 perfevents: " fmt
+
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+#include <linux/perf_event.h>
+#include <linux/platform_device.h>
+#include <linux/soc/qcom/l2-accessors.h>
+#include <linux/soc/qcom/perf_event_l2.h>
+
+/*
+ * Aggregate PMU. Implements the core pmu functions and manages
+ * the hardware PMUs.
+ */
+struct l2cache_pmu {
+	struct list_head entry;
+	u32 num_pmus;
+	struct pmu pmu;
+	int num_counters;
+	cpumask_t cpumask;
+	struct platform_device *pdev;
+};
+
+/*
+ * The cache is made-up of one or more slices, each slice has its own PMU.
+ * This structure represents one of the hardware PMUs.
+ */
+struct hml2_pmu {
+	struct perf_event *events[MAX_L2_CTRS];
+	struct l2cache_pmu *l2cache_pmu;
+	unsigned long used_mask[BITS_TO_LONGS(MAX_L2_CTRS)];
+	unsigned long group_used_mask[BITS_TO_LONGS(L2_EVT_GROUP_MAX + 1)];
+	int group_to_counter[L2_EVT_GROUP_MAX + 1];
+	int irq;
+	/* The CPU that is used for collecting events on this slice */
+	int on_cpu;
+	/* All the CPUs associated with this slice */
+	cpumask_t slice_cpus;
+	atomic64_t prev_count[MAX_L2_CTRS];
+	spinlock_t pmu_lock;
+};
+
+#define to_l2cache_pmu(p) (container_of(p, struct l2cache_pmu, pmu))
+
+static DEFINE_MUTEX(l2cache_pmu_mutex);
+static LIST_HEAD(l2cache_pmu_list);
+static DEFINE_PER_CPU(struct hml2_pmu *, cpu_to_pmu);
+static u32 l2_cycle_ctr_idx;
+static u32 l2_reset_mask;
+
+static inline u32 idx_to_reg_bit(u32 idx)
+{
+	u32 bit;
+
+	if (idx == l2_cycle_ctr_idx)
+		bit = BIT(L2CYCLE_CTR_BIT);
+	else
+		bit = BIT(idx);
+	return bit;
+}
+
+static inline struct hml2_pmu *get_hml2_pmu(int cpu)
+{
+	return per_cpu(cpu_to_pmu, cpu);
+}
+
+static void hml2_pmu__reset_on_slice(void *x)
+{
+	/* Reset all ctrs */
+	set_l2_indirect_reg(L2PMCR, L2PMCR_RESET_ALL);
+	set_l2_indirect_reg(L2PMCNTENCLR, l2_reset_mask);
+	set_l2_indirect_reg(L2PMINTENCLR, l2_reset_mask);
+	set_l2_indirect_reg(L2PMOVSCLR, l2_reset_mask);
+}
+
+static inline void hml2_pmu__reset(struct hml2_pmu *slice)
+{
+	int cpu;
+
+	if (cpumask_test_cpu(smp_processor_id(), &slice->slice_cpus)) {
+		hml2_pmu__reset_on_slice(NULL);
+		return;
+	}
+
+	/* Call each cpu in the cluster until one works */
+	for_each_cpu(cpu, &slice->slice_cpus) {
+		if (!smp_call_function_single(cpu, hml2_pmu__reset_on_slice,
+					      NULL, 1))
+			return;
+	}
+
+	dev_err(&slice->l2cache_pmu->pdev->dev,
+		"Failed to reset on cluster with cpu %d\n",
+		cpumask_first(&slice->slice_cpus));
+}
+
+static inline void hml2_pmu__enable(void)
+{
+	set_l2_indirect_reg(L2PMCR, L2PMCR_GLOBAL_ENABLE);
+}
+
+static inline void hml2_pmu__disable(void)
+{
+	set_l2_indirect_reg(L2PMCR, L2PMCR_GLOBAL_DISABLE);
+}
+
+static inline void hml2_pmu__counter_set_value(u32 idx, u64 value)
+{
+	u32 counter_reg;
+
+	if (idx == l2_cycle_ctr_idx) {
+		set_l2_indirect_reg(L2PMCCNTR, value);
+	} else {
+		counter_reg = (idx * IA_L2_REG_OFFSET) + IA_L2PMXEVCNTR_BASE;
+		set_l2_indirect_reg(counter_reg, (u32)(value & GENMASK(31, 0)));
+	}
+}
+
+static inline u64 hml2_pmu__counter_get_value(u32 idx)
+{
+	u64 value;
+	u32 counter_reg;
+
+	if (idx == l2_cycle_ctr_idx) {
+		value = get_l2_indirect_reg(L2PMCCNTR);
+	} else {
+		counter_reg = (idx * IA_L2_REG_OFFSET) + IA_L2PMXEVCNTR_BASE;
+		value = get_l2_indirect_reg(counter_reg);
+	}
+
+	return value;
+}
+
+static inline void hml2_pmu__counter_enable(u32 idx)
+{
+	u32 reg;
+
+	reg = get_l2_indirect_reg(L2PMCNTENSET);
+	reg |= idx_to_reg_bit(idx);
+	set_l2_indirect_reg(L2PMCNTENSET, reg);
+}
+
+static inline void hml2_pmu__counter_disable(u32 idx)
+{
+	set_l2_indirect_reg(L2PMCNTENCLR, idx_to_reg_bit(idx));
+}
+
+static inline void hml2_pmu__counter_enable_interrupt(u32 idx)
+{
+	u32 reg;
+
+	reg = get_l2_indirect_reg(L2PMINTENSET);
+	reg |= idx_to_reg_bit(idx);
+	set_l2_indirect_reg(L2PMINTENSET, reg);
+}
+
+static inline void hml2_pmu__counter_disable_interrupt(u32 idx)
+{
+	set_l2_indirect_reg(L2PMINTENCLR, idx_to_reg_bit(idx));
+}
+
+static inline void hml2_pmu__set_evcntcr(u32 ctr, u32 val)
+{
+	u32 evtcr_reg = (ctr * IA_L2_REG_OFFSET) + IA_L2PMXEVCNTCR_BASE;
+
+	set_l2_indirect_reg(evtcr_reg, val);
+}
+
+static inline void hml2_pmu__set_evtyper(u32 ctr, u32 val)
+{
+	u32 evtype_reg = (ctr * IA_L2_REG_OFFSET) + IA_L2PMXEVTYPER_BASE;
+
+	set_l2_indirect_reg(evtype_reg, val);
+}
+
+static void hml2_pmu__set_resr(struct hml2_pmu *slice,
+			       u32 event_group, u32 event_cc)
+{
+	u64 field;
+	u64 resr_val;
+	u32 shift;
+	unsigned long iflags;
+
+	shift = L2PMRESR_GROUP_BITS * event_group;
+	field = ((u64)(event_cc & L2PMRESR_GROUP_MASK) << shift) | L2PMRESR_EN;
+
+	spin_lock_irqsave(&slice->pmu_lock, iflags);
+
+	resr_val = get_l2_indirect_reg(L2PMRESR);
+	resr_val &= ~(L2PMRESR_GROUP_MASK << shift);
+	resr_val |= field;
+	set_l2_indirect_reg(L2PMRESR, resr_val);
+
+	spin_unlock_irqrestore(&slice->pmu_lock, iflags);
+}
+
+static inline void hml2_pmu__set_evfilter_sys_mode(u32 ctr)
+{
+	set_l2_indirect_reg((ctr * IA_L2_REG_OFFSET) + IA_L2PMXEVFILTER_BASE,
+			    L2PMXEVFILTER_SUFILTER_ALL |
+			    L2PMXEVFILTER_ORGFILTER_IDINDEP |
+			    L2PMXEVFILTER_ORGFILTER_ALL);
+}
+
+static inline u32 hml2_pmu__getreset_ovsr(void)
+{
+	u32 result = get_l2_indirect_reg(L2PMOVSSET);
+
+	set_l2_indirect_reg(L2PMOVSCLR, result);
+	return result;
+}
+
+static inline bool hml2_pmu__has_overflowed(u32 ovsr)
+{
+	return !!(ovsr & l2_reset_mask);
+}
+
+static inline bool hml2_pmu__counter_has_overflowed(u32 ovsr, u32 idx)
+{
+	return !!(ovsr & idx_to_reg_bit(idx));
+}
+
+static void l2_cache__event_update_from_slice(struct perf_event *event,
+					      struct hml2_pmu *slice)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	u64 delta64, prev, now;
+	u32 delta;
+	u32 idx = hwc->idx;
+
+	do {
+		prev = atomic64_read(&slice->prev_count[idx]);
+		now = hml2_pmu__counter_get_value(idx);
+	} while (atomic64_cmpxchg(&slice->prev_count[idx], prev, now) != prev);
+
+	if (idx == l2_cycle_ctr_idx) {
+		/*
+		 * The cycle counter is 64-bit so needs separate handling
+		 * of 64-bit delta.
+		 */
+		delta64 = now - prev;
+		local64_add(delta64, &event->count);
+	} else {
+		/*
+		 * 32-bit counters need the unsigned 32-bit math to handle
+		 * overflow and now < prev
+		 */
+		delta = now - prev;
+		local64_add(delta, &event->count);
+	}
+}
+
+static void l2_cache__slice_set_period(struct hml2_pmu *slice,
+				       struct hw_perf_event *hwc)
+{
+	u64 value = L2_MAX_PERIOD - (L2_CNT_PERIOD - 1);
+	u32 idx = hwc->idx;
+	u64 prev = atomic64_read(&slice->prev_count[idx]);
+
+	if (prev < value) {
+		value += prev;
+		atomic64_set(&slice->prev_count[idx], value);
+	} else {
+		value = prev;
+	}
+
+	hml2_pmu__counter_set_value(idx, value);
+}
+
+static int l2_cache__get_event_idx(struct hml2_pmu *slice,
+				   struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	int idx;
+
+	if (hwc->config_base == L2CYCLE_CTR_RAW_CODE) {
+		if (test_and_set_bit(l2_cycle_ctr_idx, slice->used_mask))
+			return -EAGAIN;
+
+		return l2_cycle_ctr_idx;
+	}
+
+	for (idx = 0; idx < slice->l2cache_pmu->num_counters - 1; idx++) {
+		if (!test_and_set_bit(idx, slice->used_mask)) {
+			set_bit(L2_EVT_GROUP(hwc->config_base),
+				slice->group_used_mask);
+			return idx;
+		}
+	}
+
+	/* The counters are all in use. */
+	return -EAGAIN;
+}
+
+static void l2_cache__clear_event_idx(struct hml2_pmu *slice,
+				      struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	clear_bit(L2_EVT_GROUP(hwc->config_base), slice->group_used_mask);
+}
+
+static irqreturn_t l2_cache__handle_irq(int irq_num, void *data)
+{
+	struct hml2_pmu *slice = data;
+	u32 ovsr;
+	int idx;
+
+	ovsr = hml2_pmu__getreset_ovsr();
+	if (!hml2_pmu__has_overflowed(ovsr))
+		return IRQ_NONE;
+
+	for (idx = 0; idx < slice->l2cache_pmu->num_counters; idx++) {
+		struct perf_event *event = slice->events[idx];
+		struct hw_perf_event *hwc;
+
+		if (!event)
+			continue;
+
+		if (!hml2_pmu__counter_has_overflowed(ovsr, idx))
+			continue;
+
+		l2_cache__event_update_from_slice(event, slice);
+		hwc = &event->hw;
+
+		l2_cache__slice_set_period(slice, hwc);
+	}
+
+	/*
+	 * Handle the pending perf events.
+	 *
+	 * Note: this call *must* be run with interrupts disabled. For
+	 * platforms that can have the PMU interrupts raised as an NMI, this
+	 * will not work.
+	 */
+	irq_work_run();
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * Implementation of abstract pmu functionality required by
+ * the core perf events code.
+ */
+
+static void l2_cache__pmu_enable(struct pmu *pmu)
+{
+	hml2_pmu__enable();
+}
+
+static void l2_cache__pmu_disable(struct pmu *pmu)
+{
+	hml2_pmu__disable();
+}
+
+static int l2_cache__event_init(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct hml2_pmu *slice;
+	struct perf_event *sibling;
+	struct l2cache_pmu *l2cache_pmu = to_l2cache_pmu(event->pmu);
+
+	if (event->attr.type != l2cache_pmu->pmu.type)
+		return -ENOENT;
+
+	if (hwc->sample_period) {
+		dev_warn(&l2cache_pmu->pdev->dev, "Sampling not supported\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (event->cpu < 0) {
+		dev_warn(&l2cache_pmu->pdev->dev, "Per-task mode not supported\n");
+		return -EOPNOTSUPP;
+	}
+
+	/* We cannot filter accurately so we just don't allow it. */
+	if (event->attr.exclude_user || event->attr.exclude_kernel ||
+	    event->attr.exclude_hv || event->attr.exclude_idle) {
+		dev_warn(&l2cache_pmu->pdev->dev, "Can't exclude execution levels\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (((L2_EVT_GROUP(event->attr.config) > L2_EVT_GROUP_MAX) ||
+	    (L2_EVT_PREFIX(event->attr.config) != 0) ||
+	    (L2_EVT_REG(event->attr.config) != 0)) &&
+	    (event->attr.config != L2CYCLE_CTR_RAW_CODE)) {
+		dev_warn(&l2cache_pmu->pdev->dev, "Invalid config %llx\n",
+			 event->attr.config);
+		return -EINVAL;
+	}
+
+	/* Don't allow groups with mixed PMUs, except for s/w events */
+	if (event->group_leader->pmu != event->pmu &&
+	    !is_software_event(event->group_leader)) {
+		dev_warn(&l2cache_pmu->pdev->dev,
+			 "Can't create mixed PMU group\n");
+		return -EINVAL;
+	}
+
+	list_for_each_entry(sibling, &event->group_leader->sibling_list,
+			    group_entry)
+		if (sibling->pmu != event->pmu &&
+		    !is_software_event(sibling)) {
+			dev_warn(&l2cache_pmu->pdev->dev,
+				 "Can't create mixed PMU group\n");
+			return -EINVAL;
+		}
+
+	hwc->idx = -1;
+	hwc->config_base = event->attr.config;
+
+	/*
+	 * Ensure all events are on the same cpu so all events are in the
+	 * same cpu context, to avoid races on pmu_enable etc.
+	 */
+	slice = get_hml2_pmu(event->cpu);
+	event->cpu = slice->on_cpu;
+
+	return 0;
+}
+
+static void l2_cache__event_update(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (hwc->idx < 0)
+		return;
+
+	l2_cache__event_update_from_slice(event, get_hml2_pmu(event->cpu));
+}
+
+static void l2_cache__event_start(struct perf_event *event, int flags)
+{
+	struct hml2_pmu *slice;
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+	u32 config;
+	u32 evt_prefix, event_cc, event_group;
+
+	if (idx < 0)
+		return;
+
+	hwc->state = 0;
+
+	slice = get_hml2_pmu(event->cpu);
+	l2_cache__slice_set_period(slice, hwc);
+
+	if (hwc->config_base == L2CYCLE_CTR_RAW_CODE)
+		goto out;
+
+	config = hwc->config_base;
+	evt_prefix  = L2_EVT_PREFIX(config);
+	event_cc    = L2_EVT_CODE(config);
+	event_group = L2_EVT_GROUP(config);
+
+	hml2_pmu__set_evcntcr(idx, 0x0);
+	hml2_pmu__set_evtyper(idx, event_group);
+	hml2_pmu__set_resr(slice, event_group, event_cc);
+	hml2_pmu__set_evfilter_sys_mode(idx);
+out:
+	hml2_pmu__counter_enable_interrupt(idx);
+	hml2_pmu__counter_enable(idx);
+}
+
+static void l2_cache__event_stop(struct perf_event *event, int flags)
+{
+	struct hml2_pmu *slice;
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+
+	if (idx < 0)
+		return;
+
+	if (!(hwc->state & PERF_HES_STOPPED)) {
+		slice = get_hml2_pmu(event->cpu);
+		hml2_pmu__counter_disable_interrupt(idx);
+		hml2_pmu__counter_disable(idx);
+
+		if (flags & PERF_EF_UPDATE)
+			l2_cache__event_update(event);
+		hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
+	}
+}
+
+static int l2_cache__event_add(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	int idx;
+	int err = 0;
+	struct hml2_pmu *slice;
+
+	slice = get_hml2_pmu(event->cpu);
+
+	idx = l2_cache__get_event_idx(slice, event);
+	if (idx < 0) {
+		err = idx;
+		goto out;
+	}
+
+	hwc->idx = idx;
+	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
+	slice->events[idx] = event;
+	slice->group_to_counter[L2_EVT_GROUP(hwc->config_base)] = idx;
+	atomic64_set(&slice->prev_count[idx], 0ULL);
+
+	if (flags & PERF_EF_START)
+		l2_cache__event_start(event, flags);
+
+	/* Propagate changes to the userspace mapping. */
+	perf_event_update_userpage(event);
+
+out:
+	return err;
+}
+
+static void l2_cache__event_del(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct hml2_pmu *slice;
+	int idx = hwc->idx;
+
+	if (idx < 0)
+		return;
+
+	slice = get_hml2_pmu(event->cpu);
+	l2_cache__event_stop(event, flags | PERF_EF_UPDATE);
+	slice->events[idx] = NULL;
+	clear_bit(idx, slice->used_mask);
+	l2_cache__clear_event_idx(slice, event);
+
+	perf_event_update_userpage(event);
+}
+
+static void l2_cache__event_read(struct perf_event *event)
+{
+	l2_cache__event_update(event);
+}
+
+static int l2_cache_filter_match(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	struct hml2_pmu *slice = get_hml2_pmu(event->cpu);
+	unsigned int group = L2_EVT_GROUP(hwc->config_base);
+
+	/* check for column exclusion: group already in use by another event */
+	if (test_bit(group, slice->group_used_mask) &&
+	    slice->events[slice->group_to_counter[group]] != event)
+		return 0;
+
+	return 1;
+}
+
+static ssize_t l2_cache_pmu_cpumask_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct l2cache_pmu *l2cache_pmu = to_l2cache_pmu(dev_get_drvdata(dev));
+
+	return cpumap_print_to_pagebuf(true, buf, &l2cache_pmu->cpumask);
+}
+
+static struct device_attribute l2_cache_pmu_cpumask_attr =
+		__ATTR(cpumask, S_IRUGO, l2_cache_pmu_cpumask_show, NULL);
+
+static struct attribute *l2_cache_pmu_cpumask_attrs[] = {
+	&l2_cache_pmu_cpumask_attr.attr,
+	NULL,
+};
+
+static struct attribute_group l2_cache_pmu_cpumask_group = {
+	.attrs = l2_cache_pmu_cpumask_attrs,
+};
+
+/* NRCCG format for perf RAW codes. */
+PMU_FORMAT_ATTR(l2_prefix, "config:16-19");
+PMU_FORMAT_ATTR(l2_reg,    "config:12-15");
+PMU_FORMAT_ATTR(l2_code,   "config:4-11");
+PMU_FORMAT_ATTR(l2_grp,    "config:0-3");
+static struct attribute *l2_cache_pmu_formats[] = {
+	&format_attr_l2_prefix.attr,
+	&format_attr_l2_reg.attr,
+	&format_attr_l2_code.attr,
+	&format_attr_l2_grp.attr,
+	NULL,
+};
+
+static struct attribute_group l2_cache_pmu_format_group = {
+	.name = "format",
+	.attrs = l2_cache_pmu_formats,
+};
+
+static const struct attribute_group *l2_cache_pmu_attr_grps[] = {
+	&l2_cache_pmu_format_group,
+	&l2_cache_pmu_cpumask_group,
+	NULL,
+};
+
+/*
+ * Generic device handlers
+ */
+
+static const struct acpi_device_id l2_cache_pmu_acpi_match[] = {
+	{ "QCOM8130", },
+	{ }
+};
+
+static int get_num_counters(void)
+{
+	int val;
+
+	val = get_l2_indirect_reg(L2PMCR);
+
+	/*
+	 * Read number of counters from L2PMCR and add 1
+	 * for the cycle counter.
+	 */
+	return ((val >> L2PMCR_NUM_EV_SHIFT) & L2PMCR_NUM_EV_MASK) + 1;
+}
+
+static int l2cache_pmu_online_cpu(unsigned int cpu)
+{
+	struct hml2_pmu *slice;
+	struct l2cache_pmu *l2cache_pmu;
+	cpumask_t slice_online_cpus;
+
+	mutex_lock(&l2cache_pmu_mutex);
+	list_for_each_entry(l2cache_pmu, &l2cache_pmu_list, entry) {
+		slice = get_hml2_pmu(cpu);
+		cpumask_and(&slice_online_cpus, &slice->slice_cpus,
+			    cpu_online_mask);
+		if (cpumask_weight(&slice_online_cpus) == 1) {
+			/* all CPUs on this slice were down, use this one */
+			slice->on_cpu = cpu;
+			cpumask_set_cpu(cpu, &l2cache_pmu->cpumask);
+			WARN_ON(irq_set_affinity(slice->irq, cpumask_of(cpu)));
+		}
+	}
+	mutex_unlock(&l2cache_pmu_mutex);
+
+	return 0;
+}
+
+static int l2cache_pmu_offline_cpu(unsigned int cpu)
+{
+	struct hml2_pmu *slice;
+	struct l2cache_pmu *l2cache_pmu;
+	cpumask_t slice_online_cpus;
+	unsigned int target;
+
+	mutex_lock(&l2cache_pmu_mutex);
+	list_for_each_entry(l2cache_pmu, &l2cache_pmu_list, entry) {
+		if (!cpumask_test_and_clear_cpu(cpu, &l2cache_pmu->cpumask))
+			break;
+		slice = get_hml2_pmu(cpu);
+		cpumask_and(&slice_online_cpus, &slice->slice_cpus,
+			    cpu_online_mask);
+		/* Any other CPU for this slice which is still online */
+		target = cpumask_any_but(&slice_online_cpus, cpu);
+		if (target >= nr_cpu_ids)
+			break;
+		perf_pmu_migrate_context(&l2cache_pmu->pmu, cpu, target);
+		slice->on_cpu = target;
+		cpumask_set_cpu(target, &l2cache_pmu->cpumask);
+		WARN_ON(irq_set_affinity(slice->irq, cpumask_of(target)));
+	}
+	mutex_unlock(&l2cache_pmu_mutex);
+
+	return 0;
+}
+
+static int l2_cache_pmu_probe_slice(struct device *dev, void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev->parent);
+	struct platform_device *sdev = to_platform_device(dev);
+	struct l2cache_pmu *l2cache_pmu = data;
+	struct hml2_pmu *slice;
+	struct acpi_device *device;
+	int irq;
+	int err;
+	int logical_cpu;
+	unsigned long fw_slice_id;
+
+	if (acpi_bus_get_device(ACPI_HANDLE(dev), &device))
+		return -ENODEV;
+
+	if (kstrtol(device->pnp.unique_id, 10, &fw_slice_id) < 0) {
+		dev_err(&pdev->dev, "unable to read ACPI uid\n");
+		return -ENODEV;
+	}
+
+	irq = platform_get_irq(sdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev,
+			"Failed to get valid irq for slice %ld\n", fw_slice_id);
+		return irq;
+	}
+
+	slice = devm_kzalloc(&pdev->dev, sizeof(*slice), GFP_KERNEL);
+	if (!slice)
+		return -ENOMEM;
+
+	slice->l2cache_pmu = l2cache_pmu;
+	for_each_present_cpu(logical_cpu) {
+		if (topology_physical_package_id(logical_cpu) == fw_slice_id) {
+			cpumask_set_cpu(logical_cpu, &slice->slice_cpus);
+			per_cpu(cpu_to_pmu, logical_cpu) = slice;
+		}
+	}
+	slice->irq = irq;
+
+	if (cpumask_empty(&slice->slice_cpus)) {
+		dev_err(&pdev->dev, "No CPUs found for L2 cache instance %ld\n",
+			fw_slice_id);
+		return -ENODEV;
+	}
+
+	/* Pick one CPU to be the preferred one to use in the slice */
+	slice->on_cpu = cpumask_first(&slice->slice_cpus);
+
+	if (irq_set_affinity(irq, cpumask_of(slice->on_cpu))) {
+		dev_err(&pdev->dev,
+			"Unable to set irq affinity (irq=%d, cpu=%d)\n",
+			irq, slice->on_cpu);
+		return -ENODEV;
+	}
+
+	err = devm_request_irq(
+		&pdev->dev, irq, l2_cache__handle_irq,
+		IRQF_NOBALANCING, "l2-cache-pmu", slice);
+	if (err) {
+		dev_err(&pdev->dev,
+			"Unable to request IRQ%d for L2 PMU counters\n",
+			irq);
+		return err;
+	}
+
+	dev_info(&pdev->dev,
+		 "Registered L2 cache PMU instance %ld with %d CPUs\n",
+		 fw_slice_id, cpumask_weight(&slice->slice_cpus));
+
+	slice->pmu_lock = __SPIN_LOCK_UNLOCKED(slice->pmu_lock);
+	cpumask_set_cpu(slice->on_cpu, &l2cache_pmu->cpumask);
+
+	hml2_pmu__reset(slice);
+	l2cache_pmu->num_pmus++;
+
+	return 0;
+}
+
+static int l2_cache_pmu_probe(struct platform_device *pdev)
+{
+	int err;
+	struct l2cache_pmu *l2cache_pmu;
+
+	l2cache_pmu =
+		devm_kzalloc(&pdev->dev, sizeof(*l2cache_pmu), GFP_KERNEL);
+	if (!l2cache_pmu)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, l2cache_pmu);
+	l2cache_pmu->pmu = (struct pmu) {
+		/* suffix is instance id for future use with multiple sockets */
+		.name		= "l2cache_0",
+		.task_ctx_nr    = perf_invalid_context,
+		.pmu_enable	= l2_cache__pmu_enable,
+		.pmu_disable	= l2_cache__pmu_disable,
+		.event_init	= l2_cache__event_init,
+		.add		= l2_cache__event_add,
+		.del		= l2_cache__event_del,
+		.start		= l2_cache__event_start,
+		.stop		= l2_cache__event_stop,
+		.read		= l2_cache__event_read,
+		.attr_groups	= l2_cache_pmu_attr_grps,
+		.filter_match   = l2_cache_filter_match,
+	};
+
+	l2cache_pmu->num_counters = get_num_counters();
+	l2cache_pmu->pdev = pdev;
+	l2_cycle_ctr_idx = l2cache_pmu->num_counters - 1;
+	l2_reset_mask = GENMASK(l2cache_pmu->num_counters - 2, 0) |
+		L2PM_CC_ENABLE;
+
+	cpumask_clear(&l2cache_pmu->cpumask);
+
+	/* Read slice info and initialize each slice */
+	err = device_for_each_child(&pdev->dev, l2cache_pmu,
+				    l2_cache_pmu_probe_slice);
+	if (err < 0)
+		return err;
+
+	if (l2cache_pmu->num_pmus == 0) {
+		dev_err(&pdev->dev, "No hardware L2 cache PMUs found\n");
+		return -ENODEV;
+	}
+
+	err = perf_pmu_register(&l2cache_pmu->pmu, l2cache_pmu->pmu.name, -1);
+	if (err < 0) {
+		dev_err(&pdev->dev, "Error %d registering L2 cache PMU\n", err);
+		return err;
+	}
+
+	dev_info(&pdev->dev, "Registered L2 cache PMU using %d HW PMUs\n",
+		 l2cache_pmu->num_pmus);
+	mutex_lock(&l2cache_pmu_mutex);
+	list_add(&l2cache_pmu->entry, &l2cache_pmu_list);
+	mutex_unlock(&l2cache_pmu_mutex);
+
+	return err;
+}
+
+static int l2_cache_pmu_remove(struct platform_device *pdev)
+{
+	struct l2cache_pmu *l2cache_pmu =
+		to_l2cache_pmu(platform_get_drvdata(pdev));
+
+	mutex_lock(&l2cache_pmu_mutex);
+	list_del(&l2cache_pmu->entry);
+	mutex_unlock(&l2cache_pmu_mutex);
+	perf_pmu_unregister(&l2cache_pmu->pmu);
+	return 0;
+}
+
+static struct platform_driver l2_cache_pmu_driver = {
+	.driver = {
+		.name = "qcom-l2cache-pmu",
+		.owner = THIS_MODULE,
+		.acpi_match_table = ACPI_PTR(l2_cache_pmu_acpi_match),
+	},
+	.probe = l2_cache_pmu_probe,
+	.remove = l2_cache_pmu_remove,
+};
+
+static int __init register_l2_cache_pmu_driver(void)
+{
+	int err;
+
+	err = cpuhp_setup_state_nocalls(CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
+					"AP_PERF_ARM_QCOM_L2_ONLINE",
+					l2cache_pmu_online_cpu,
+					l2cache_pmu_offline_cpu);
+	if (err)
+		return err;
+	return platform_driver_register(&l2_cache_pmu_driver);
+}
+device_initcall(register_l2_cache_pmu_driver);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 242bf53..69597b9 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -86,6 +86,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_S390_SF_ONLINE,
 	CPUHP_AP_PERF_ARM_CCI_ONLINE,
 	CPUHP_AP_PERF_ARM_CCN_ONLINE,
+	CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
 	CPUHP_AP_WORKQUEUE_ONLINE,
 	CPUHP_AP_RCUTREE_ONLINE,
 	CPUHP_AP_NOTIFY_ONLINE,
diff --git a/include/linux/soc/qcom/perf_event_l2.h b/include/linux/soc/qcom/perf_event_l2.h
new file mode 100644
index 0000000..754970a
--- /dev/null
+++ b/include/linux/soc/qcom/perf_event_l2.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2015, 2016 The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __QCOM_PERF_EVENT_L2_H
+#define __QCOM_PERF_EVENT_L2_H
+
+#define MAX_L2_CTRS             17
+
+#define L2PMCR_NUM_EV_SHIFT     11
+#define L2PMCR_NUM_EV_MASK      0x1F
+
+#define L2PMCR                  0x400
+#define L2PMCNTENCLR            0x403
+#define L2PMCNTENSET            0x404
+#define L2PMINTENCLR            0x405
+#define L2PMINTENSET            0x406
+#define L2PMOVSCLR              0x407
+#define L2PMOVSSET              0x408
+#define L2PMCCNTCR              0x409
+#define L2PMCCNTR               0x40A
+#define L2PMCCNTSR              0x40C
+#define L2PMRESR                0x410
+#define IA_L2PMXEVCNTCR_BASE    0x420
+#define IA_L2PMXEVCNTR_BASE     0x421
+#define IA_L2PMXEVFILTER_BASE   0x423
+#define IA_L2PMXEVTYPER_BASE    0x424
+
+#define IA_L2_REG_OFFSET        0x10
+
+#define L2PMXEVFILTER_SUFILTER_ALL      0x000E0000
+#define L2PMXEVFILTER_ORGFILTER_IDINDEP 0x00000004
+#define L2PMXEVFILTER_ORGFILTER_ALL     0x00000003
+
+#define L2PM_CC_ENABLE          0x80000000
+
+#define L2EVTYPER_REG_SHIFT     3
+
+#define L2PMRESR_GROUP_BITS     8
+#define L2PMRESR_GROUP_MASK     GENMASK(7, 0)
+
+#define L2CYCLE_CTR_BIT         31
+#define L2CYCLE_CTR_RAW_CODE    0xFE
+
+#define L2PMCR_RESET_ALL        0x6
+#define L2PMCR_GLOBAL_ENABLE    0x1
+#define L2PMCR_GLOBAL_DISABLE   0x0
+
+#define L2PMRESR_EN             ((u64)1 << 63)
+
+#define L2_EVT_MASK             0xFFFFF
+#define L2_EVT_PFX_MASK         0xF0000
+#define L2_EVT_REG_MASK         0x0F000
+#define L2_EVT_CODE_MASK        0x00FF0
+#define L2_EVT_GRP_MASK         0x0000F
+#define L2_EVT_PFX_SHIFT        16
+#define L2_EVT_REG_SHIFT        12
+#define L2_EVT_CODE_SHIFT        4
+#define L2_EVT_GRP_SHIFT         0
+#define L2_EVT_PREFIX(event) (((event) & L2_EVT_PFX_MASK) >> L2_EVT_PFX_SHIFT)
+#define L2_EVT_REG(event)    (((event) & L2_EVT_REG_MASK) >> L2_EVT_REG_SHIFT)
+#define L2_EVT_CODE(event)   (((event) & L2_EVT_CODE_MASK) >> L2_EVT_CODE_SHIFT)
+#define L2_EVT_GROUP(event)  (((event) & L2_EVT_GRP_MASK) >> L2_EVT_GRP_SHIFT)
+
+#define L2_EVT_GROUP_MAX         7
+
+#define L2_MAX_PERIOD           U32_MAX
+#define L2_CNT_PERIOD           (U32_MAX - GENMASK(26, 0))
+
+#endif
-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.

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