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 <nlee...@codeaurora.org>
---
 drivers/soc/qcom/Kconfig               |  10 +
 drivers/soc/qcom/Makefile              |   1 +
 drivers/soc/qcom/perf_event_l2.c       | 828 +++++++++++++++++++++++++++++++++
 include/linux/soc/qcom/perf_event_l2.h |  81 ++++
 4 files changed, 920 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..dfd5c3a
--- /dev/null
+++ b/drivers/soc/qcom/perf_event_l2.c
@@ -0,0 +1,828 @@
+/* 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/perf_event_l2.h>
+#include <linux/soc/qcom/l2-accessors.h>
+
+/*
+ * 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];
+       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;
+};
+
+/*
+ * Aggregate PMU. Implements the core pmu functions and manages
+ * the hardware PMUs.
+ */
+struct l2cache_pmu {
+       u32 num_pmus;
+       struct pmu pmu;
+       int num_counters;
+       cpumask_t cpumask;
+       struct notifier_block cpu_nb;
+       struct platform_device *pdev;
+};
+
+#define to_l2cache_pmu(p) (container_of(p, struct l2cache_pmu, pmu))
+
+static DEFINE_PER_CPU(struct hml2_pmu *, cpu_to_pmu);
+static struct l2cache_pmu l2cache_pmu = { 0 };
+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(&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 < 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 < 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;
+
+       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)
+{
+       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_cpu_notifier(struct notifier_block *nb,
+                                   unsigned long action, void *hcpu)
+{
+       struct l2cache_pmu *l2cache =
+               container_of(nb, struct l2cache_pmu, cpu_nb);
+       unsigned int cpu = (long)hcpu;
+       unsigned int target;
+       struct hml2_pmu *slice;
+       cpumask_t slice_online_cpus;
+
+       switch (action & ~CPU_TASKS_FROZEN) {
+       case CPU_DOWN_PREPARE:
+               if (!cpumask_test_and_clear_cpu(cpu, &l2cache->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, cpu, target);
+               slice->on_cpu = target;
+               cpumask_set_cpu(target, &l2cache->cpumask);
+               WARN_ON(irq_set_affinity(slice->irq, cpumask_of(target)));
+               break;
+       case CPU_ONLINE:
+               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->cpumask);
+                       WARN_ON(irq_set_affinity(slice->irq, cpumask_of(cpu)));
+               }
+               break;
+       }
+
+       return NOTIFY_OK;
+}
+
+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 = 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;
+
+       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->cpumask);
+
+       hml2_pmu__reset(slice);
+       l2cache->num_pmus++;
+
+       return 0;
+}
+
+static int l2_cache_pmu_probe(struct platform_device *pdev)
+{
+       int err;
+
+       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 PMUs found\n");
+               return -ENODEV;
+       }
+
+       l2cache_pmu.cpu_nb.notifier_call = l2cache_pmu_cpu_notifier;
+       l2cache_pmu.cpu_nb.priority = CPU_PRI_PERF + 1;
+       err = register_cpu_notifier(&l2cache_pmu.cpu_nb);
+       if (err)
+               return err;
+
+       err = perf_pmu_register(&l2cache_pmu.pmu, l2cache_pmu.pmu.name, -1);
+       if (err < 0)
+               goto probe_err;
+       else
+               dev_info(&pdev->dev,
+                        "Registered L2 cache PMU using %d HW PMUs\n",
+                        l2cache_pmu.num_pmus);
+
+       return err;
+
+probe_err:
+       dev_err(&pdev->dev, "Failed to register L2 cache PMU (%d)\n", err);
+       unregister_cpu_notifier(&l2cache_pmu.cpu_nb);
+       return err;
+}
+
+static int l2_cache_pmu_remove(struct platform_device *pdev)
+{
+       unregister_cpu_notifier(&l2cache_pmu.cpu_nb);
+       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)
+{
+       return platform_driver_register(&l2_cache_pmu_driver);
+}
+device_initcall(register_l2_cache_pmu_driver);
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..1f5a79f
--- /dev/null
+++ b/include/linux/soc/qcom/perf_event_l2.h
@@ -0,0 +1,81 @@
+/*
+ * 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))
+
+#define MAX_CPUS_IN_CLUSTER     16
+
+#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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