Re: [PATCH v7 2/2] ThunderX2, perf : Add Cavium ThunderX2 SoC UNCORE PMU driver
From: Ganapatrao Kulkarni
Date: Tue Nov 20 2018 - 00:40:50 EST
Hi Suzuki,
Thanks for the comments, will update next version with your comments.
On Fri, Nov 16, 2018 at 4:14 AM Suzuki K Poulose <suzuki.poulose@xxxxxxx> wrote:
>
> Hi,
>
> On 10/25/2018 06:59 AM, Kulkarni, Ganapatrao wrote:
> > This patch adds a perf driver for the PMU UNCORE devices DDR4 Memory
> > Controller(DMC) and Level 3 Cache(L3C). Each PMU supports up to 4
> > counters. All counters lack overflow interrupt and are
> > sampled periodically.
>
> The patch looks OK overall. Some minor comments below.
>
> >
> > Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@xxxxxxxxxx>
> > ---
> > drivers/perf/Kconfig | 9 +
> > drivers/perf/Makefile | 1 +
> > drivers/perf/thunderx2_pmu.c | 867 +++++++++++++++++++++++++++++++++++
> > include/linux/cpuhotplug.h | 1 +
> > 4 files changed, 878 insertions(+)
> > create mode 100644 drivers/perf/thunderx2_pmu.c
> >
> > diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
> > index 08ebaf7cca8b..c1956b1af2bb 100644
> > --- a/drivers/perf/Kconfig
> > +++ b/drivers/perf/Kconfig
> > @@ -87,6 +87,15 @@ config QCOM_L3_PMU
> > Adds the L3 cache PMU into the perf events subsystem for
> > monitoring L3 cache events.
> >
> > +config THUNDERX2_PMU
> > + tristate "Cavium ThunderX2 SoC PMU UNCORE"
> > + depends on ARCH_THUNDER2 && ARM64 && ACPI && NUMA
> > + default m
> > + help
> > + Provides support for ThunderX2 UNCORE events.
> > + The SoC has PMU support in its L3 cache controller (L3C) and
> > + in the DDR4 Memory Controller (DMC).
> > +
> > config XGENE_PMU
> > depends on ARCH_XGENE
> > bool "APM X-Gene SoC PMU"
> > diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
> > index b3902bd37d53..909f27fd9db3 100644
> > --- a/drivers/perf/Makefile
> > +++ b/drivers/perf/Makefile
> > @@ -7,5 +7,6 @@ obj-$(CONFIG_ARM_PMU_ACPI) += arm_pmu_acpi.o
> > obj-$(CONFIG_HISI_PMU) += hisilicon/
> > obj-$(CONFIG_QCOM_L2_PMU) += qcom_l2_pmu.o
> > obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
> > +obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
> > obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
> > obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
> > diff --git a/drivers/perf/thunderx2_pmu.c b/drivers/perf/thunderx2_pmu.c
> > new file mode 100644
> > index 000000000000..450d36c6a1e1
> > --- /dev/null
> > +++ b/drivers/perf/thunderx2_pmu.c
> > @@ -0,0 +1,867 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * CAVIUM THUNDERX2 SoC PMU UNCORE
> > + * Copyright (C) 2018 Cavium Inc.
> > + * Author: Ganapatrao Kulkarni <gkulkarni@xxxxxxxxxx>
> > + */
> > +
> > +#include <linux/acpi.h>
> > +#include <linux/cpuhotplug.h>
> > +#include <linux/perf_event.h>
> > +#include <linux/platform_device.h>
> > +
> > +/* Each ThunderX2(TX2) Socket has a L3C and DMC UNCORE PMU device.
> > + * Each UNCORE PMU device consists of 4 independent programmable counters.
> > + * Counters are 32 bit and do not support overflow interrupt,
> > + * they need to be sampled before overflow(i.e, at every 2 seconds).
> > + */
> > +
> > +#define TX2_PMU_MAX_COUNTERS 4
> > +#define TX2_PMU_DMC_CHANNELS 8
> > +#define TX2_PMU_L3_TILES 16
> > +
> > +#define TX2_PMU_HRTIMER_INTERVAL (2 * NSEC_PER_SEC)
> > +#define GET_EVENTID(ev) ((ev->hw.config) & 0x1ff)
>
> > +#define GET_COUNTERID(ev) ((ev->hw.idx) & 0xf)
>
> If the number of counters are 4, should the mask be 0x3 instead ?
>
> > +#define DMC_EVENT_CFG(idx, val) ((val) << (((idx) * 8) + 1))
>
> If I understand this correctly, you are accommodating bits[5:1] of the
> 8bit counter by "+1". It is worth adding a comment about the bit
> position here.
>
>
> > +
> > +#define L3C_COUNTER_CTL 0xA8
> > +#define L3C_COUNTER_DATA 0xAC
> > +#define DMC_COUNTER_CTL 0x234
> > +#define DMC_COUNTER_DATA 0x240
> > +
> > +/* L3C event IDs */
> > +#define L3_EVENT_READ_REQ 0xD
> > +#define L3_EVENT_WRITEBACK_REQ 0xE
> > +#define L3_EVENT_INV_N_WRITE_REQ 0xF
> > +#define L3_EVENT_INV_REQ 0x10
> > +#define L3_EVENT_EVICT_REQ 0x13
> > +#define L3_EVENT_INV_N_WRITE_HIT 0x14
> > +#define L3_EVENT_INV_HIT 0x15
> > +#define L3_EVENT_READ_HIT 0x17
> > +#define L3_EVENT_MAX 0x18
> > +
> > +/* DMC event IDs */
> > +#define DMC_EVENT_COUNT_CYCLES 0x1
> > +#define DMC_EVENT_WRITE_TXNS 0xB
> > +#define DMC_EVENT_DATA_TRANSFERS 0xD
> > +#define DMC_EVENT_READ_TXNS 0xF
> > +#define DMC_EVENT_MAX 0x10
> > +
> > +enum tx2_uncore_type {
> > + PMU_TYPE_L3C,
> > + PMU_TYPE_DMC,
> > + PMU_TYPE_INVALID,
> > +};
> > +
> > +/*
> > + * pmu on each socket has 2 uncore devices(dmc and l3c),
> > + * each device has 4 counters.
> > + */
> > +struct tx2_uncore_pmu {
> > + struct hlist_node hpnode;
> > + struct list_head entry;
> > + struct pmu pmu;
> > + char *name;
> > + int node;
> > + int cpu;
> > + u32 max_counters;
> > + u32 prorate_factor;
> > + u32 max_events;
> > + u64 hrtimer_interval;
> > + void __iomem *base;
> > + DECLARE_BITMAP(active_counters, TX2_PMU_MAX_COUNTERS);
> > + struct perf_event *events[TX2_PMU_MAX_COUNTERS];
> > + struct device *dev;
> > + struct hrtimer hrtimer;
> > + const struct attribute_group **attr_groups;
> > + enum tx2_uncore_type type;
> > + raw_spinlock_t lock;
> > + void (*init_cntr_base)(struct perf_event *event,
> > + struct tx2_uncore_pmu *tx2_pmu);
> > + void (*stop_event)(struct perf_event *event);
> > + void (*start_event)(struct perf_event *event, int flags);
> > +};
> > +
> > +static LIST_HEAD(tx2_pmus);
> > +
> > +static inline struct tx2_uncore_pmu *pmu_to_tx2_pmu(struct pmu *pmu)
> > +{
> > + return container_of(pmu, struct tx2_uncore_pmu, pmu);
> > +}
> > +
> > +/*
> > + * sysfs format attributes
> > + */
> > +static ssize_t tx2_pmu_format_show(struct device *dev,
> > + struct device_attribute *attr, char *buf)
> > +{
> > + struct dev_ext_attribute *eattr;
> > +
> > + eattr = container_of(attr, struct dev_ext_attribute, attr);
> > + return sprintf(buf, "%s\n", (char *) eattr->var);
> > +}
> > +
> > +#define FORMAT_ATTR(_name, _config) \
> > + (&((struct dev_ext_attribute[]) { \
> > + { \
> > + .attr = __ATTR(_name, 0444, tx2_pmu_format_show, NULL), \
> > + .var = (void *) _config, \
> > + } \
> > + })[0].attr.attr)
> > +
> > +static struct attribute *l3c_pmu_format_attrs[] = {
> > + FORMAT_ATTR(event, "config:0-4"),
> > + NULL,
> > +};
> > +
> > +static struct attribute *dmc_pmu_format_attrs[] = {
> > + FORMAT_ATTR(event, "config:0-4"),
> > + NULL,
> > +};
> > +
> > +static const struct attribute_group l3c_pmu_format_attr_group = {
> > + .name = "format",
> > + .attrs = l3c_pmu_format_attrs,
> > +};
> > +
> > +static const struct attribute_group dmc_pmu_format_attr_group = {
> > + .name = "format",
> > + .attrs = dmc_pmu_format_attrs,
> > +};
> > +
> > +/*
> > + * sysfs event attributes
> > + */
> > +static ssize_t tx2_pmu_event_show(struct device *dev,
> > + struct device_attribute *attr, char *buf)
> > +{
> > + struct dev_ext_attribute *eattr;
> > +
> > + eattr = container_of(attr, struct dev_ext_attribute, attr);
> > + return sprintf(buf, "config=0x%lx\n", (unsigned long) eattr->var);
> > +}
> > +
> > +#define EVENT_ATTR(_name, _config) \
> > + (&((struct dev_ext_attribute[]) { \
> > + { \
> > + .attr = __ATTR(_name, 0444, tx2_pmu_event_show, NULL), \
> > + .var = (void *) _config, \
> > + } \
> > + })[0].attr.attr)
> > +
> > +static struct attribute *l3c_pmu_events_attrs[] = {
> > + EVENT_ATTR(read_request, L3_EVENT_READ_REQ),
> > + EVENT_ATTR(writeback_request, L3_EVENT_WRITEBACK_REQ),
> > + EVENT_ATTR(inv_nwrite_request, L3_EVENT_INV_N_WRITE_REQ),
> > + EVENT_ATTR(inv_request, L3_EVENT_INV_REQ),
> > + EVENT_ATTR(evict_request, L3_EVENT_EVICT_REQ),
> > + EVENT_ATTR(inv_nwrite_hit, L3_EVENT_INV_N_WRITE_HIT),
> > + EVENT_ATTR(inv_hit, L3_EVENT_INV_HIT),
> > + EVENT_ATTR(read_hit, L3_EVENT_READ_HIT),
> > + NULL,
> > +};
> > +
> > +static struct attribute *dmc_pmu_events_attrs[] = {
> > + EVENT_ATTR(cnt_cycles, DMC_EVENT_COUNT_CYCLES),
> > + EVENT_ATTR(write_txns, DMC_EVENT_WRITE_TXNS),
> > + EVENT_ATTR(data_transfers, DMC_EVENT_DATA_TRANSFERS),
> > + EVENT_ATTR(read_txns, DMC_EVENT_READ_TXNS),
> > + NULL,
> > +};
> > +
> > +static const struct attribute_group l3c_pmu_events_attr_group = {
> > + .name = "events",
> > + .attrs = l3c_pmu_events_attrs,
> > +};
> > +
> > +static const struct attribute_group dmc_pmu_events_attr_group = {
> > + .name = "events",
> > + .attrs = dmc_pmu_events_attrs,
> > +};
> > +
> > +/*
> > + * sysfs cpumask attributes
> > + */
> > +static ssize_t cpumask_show(struct device *dev, struct device_attribute
> > + *attr, char *buf)
>
> nit: Coding style issues. Please don't split the parameter definition.
> Also check the alignment.
>
>
> > +{
> > + struct tx2_uncore_pmu *tx2_pmu;
> > +
> > + tx2_pmu = pmu_to_tx2_pmu(dev_get_drvdata(dev));
> > + return cpumap_print_to_pagebuf(true, buf, cpumask_of(tx2_pmu->cpu));
> > +}
> > +static DEVICE_ATTR_RO(cpumask);
> > +
> > +static struct attribute *tx2_pmu_cpumask_attrs[] = {
> > + &dev_attr_cpumask.attr,
> > + NULL,
> > +};
> > +
> > +static const struct attribute_group pmu_cpumask_attr_group = {
> > + .attrs = tx2_pmu_cpumask_attrs,
> > +};
> > +
> > +/*
> > + * Per PMU device attribute groups
> > + */
> > +static const struct attribute_group *l3c_pmu_attr_groups[] = {
> > + &l3c_pmu_format_attr_group,
> > + &pmu_cpumask_attr_group,
> > + &l3c_pmu_events_attr_group,
> > + NULL
> > +};
> > +
> > +static const struct attribute_group *dmc_pmu_attr_groups[] = {
> > + &dmc_pmu_format_attr_group,
> > + &pmu_cpumask_attr_group,
> > + &dmc_pmu_events_attr_group,
> > + NULL
> > +};
> > +
> > +static inline u32 reg_readl(unsigned long addr)
> > +{
> > + return readl((void __iomem *)addr);
> > +}
> > +
> > +static inline void reg_writel(u32 val, unsigned long addr)
> > +{
> > + writel(val, (void __iomem *)addr);
> > +}
> > +
> > +static int alloc_counter(struct tx2_uncore_pmu *tx2_pmu)
> > +{
> > + int counter;
> > +
> > + counter = find_first_zero_bit(tx2_pmu->active_counters,
> > + tx2_pmu->max_counters);
> > + if (counter == tx2_pmu->max_counters)
> > + return -ENOSPC;
> > +
> > + set_bit(counter, tx2_pmu->active_counters);
> > + return counter;
> > +}
> > +
> > +static inline void free_counter(struct tx2_uncore_pmu *tx2_pmu, int counter)
> > +{
> > + clear_bit(counter, tx2_pmu->active_counters);
> > +}
> > +
> > +static void init_cntr_base_l3c(struct perf_event *event,
> > + struct tx2_uncore_pmu *tx2_pmu)
> > +{
> > + struct hw_perf_event *hwc = &event->hw;
> > +
> > + /* counter ctrl/data reg offset at 8 */
> > + hwc->config_base = (unsigned long)tx2_pmu->base
> > + + L3C_COUNTER_CTL + (8 * GET_COUNTERID(event));
> > + hwc->event_base = (unsigned long)tx2_pmu->base
> > + + L3C_COUNTER_DATA + (8 * GET_COUNTERID(event));
> > +}
> > +
> > +static void init_cntr_base_dmc(struct perf_event *event,
> > + struct tx2_uncore_pmu *tx2_pmu)
> > +{
> > + struct hw_perf_event *hwc = &event->hw;
> > +
> > + hwc->config_base = (unsigned long)tx2_pmu->base
> > + + DMC_COUNTER_CTL;
> > + /* counter data reg offset at 0xc */
> > + hwc->event_base = (unsigned long)tx2_pmu->base
> > + + DMC_COUNTER_DATA + (0xc * GET_COUNTERID(event));
> > +}
> > +
> > +static void uncore_start_event_l3c(struct perf_event *event, int flags)
> > +{
> > + u32 val;
> > + struct hw_perf_event *hwc = &event->hw;
> > +
> > + /* event id encoded in bits [07:03] */
> > + val = GET_EVENTID(event) << 3;
> > + reg_writel(val, hwc->config_base);
> > + local64_set(&hwc->prev_count, 0);
> > + reg_writel(0, hwc->event_base);
> > +}
> > +
> > +static inline void uncore_stop_event_l3c(struct perf_event *event)
> > +{
> > + reg_writel(0, event->hw.config_base);
> > +}
> > +
> > +static void uncore_start_event_dmc(struct perf_event *event, int flags)
> > +{
> > + u32 val;
> > + struct hw_perf_event *hwc = &event->hw;
> > + int idx = GET_COUNTERID(event);
> > + int event_id = GET_EVENTID(event);
> > +
> > + /* enable and start counters.
> > + * 8 bits for each counter, bits[05:01] of a counter to set event type.
> > + */
> > + val = reg_readl(hwc->config_base);
> > + val &= ~DMC_EVENT_CFG(idx, 0x1f);
> > + val |= DMC_EVENT_CFG(idx, event_id);
> > + reg_writel(val, hwc->config_base);
> > + local64_set(&hwc->prev_count, 0);
> > + reg_writel(0, hwc->event_base);
> > +}
> > +
> > +static void uncore_stop_event_dmc(struct perf_event *event)
> > +{
> > + u32 val;
> > + struct hw_perf_event *hwc = &event->hw;
> > + int idx = GET_COUNTERID(event);
> > +
> > + /* clear event type(bits[05:01]) to stop counter */
> > + val = reg_readl(hwc->config_base);
> > + val &= ~DMC_EVENT_CFG(idx, 0x1f);
> > + reg_writel(val, hwc->config_base);
> > +}
> > +
> > +static void tx2_uncore_event_update(struct perf_event *event)
> > +{
> > + s64 prev, delta, new = 0;
> > + struct hw_perf_event *hwc = &event->hw;
> > + struct tx2_uncore_pmu *tx2_pmu;
> > + enum tx2_uncore_type type;
> > + u32 prorate_factor;
> > +
> > + tx2_pmu = pmu_to_tx2_pmu(event->pmu);
> > + type = tx2_pmu->type;
> > + prorate_factor = tx2_pmu->prorate_factor;
> > +
> > + new = reg_readl(hwc->event_base);
> > + prev = local64_xchg(&hwc->prev_count, new);
> > +
> > + /* handles rollover of 32 bit counter */
> > + delta = (u32)(((1UL << 32) - prev) + new);
> > +
> > + /* DMC event data_transfers granularity is 16 Bytes, convert it to 64 */
> > + if (type == PMU_TYPE_DMC &&
> > + GET_EVENTID(event) == DMC_EVENT_DATA_TRANSFERS)
> > + delta = delta/4;
> > +
> > + /* L3C and DMC has 16 and 8 interleave channels respectively.
> > + * The sampled value is for channel 0 and multiplied with
> > + * prorate_factor to get the count for a device.
> > + */
> > + local64_add(delta * prorate_factor, &event->count);
> > +}
> > +
> > +enum tx2_uncore_type get_tx2_pmu_type(struct acpi_device *adev)
> > +{
> > + int i = 0;
> > + struct acpi_tx2_pmu_device {
> > + __u8 id[ACPI_ID_LEN];
> > + enum tx2_uncore_type type;
> > + } devices[] = {
> > + {"CAV901D", PMU_TYPE_L3C},
> > + {"CAV901F", PMU_TYPE_DMC},
> > + {"", PMU_TYPE_INVALID}
> > + };
> > +
> > + while (devices[i].type != PMU_TYPE_INVALID) {
> > + if (!strcmp(acpi_device_hid(adev), devices[i].id))
> > + return devices[i].type;
> > + i++;
> > + }
> > + return PMU_TYPE_INVALID;
>
> minor nit: The above could be folded to :
>
> while (devices[i].type != PMU_TYPE_INVALID) {
> if (!strcmp(acpi_device_hid(adev), devices[i].id))
> break;
> i++;
> }
>
> return devices[i].type;
>
> > +}
> > +
> > +static bool tx2_uncore_validate_event(struct pmu *pmu,
> > + struct perf_event *event, int *counters)
> > +{
> > + if (is_software_event(event))
> > + return true;
> > + /* Reject groups spanning multiple HW PMUs. */
> > + if (event->pmu != pmu)
> > + return false;
> > +
> > + *counters = *counters + 1;
> > + return true;
> > +}
> > +
> > +/*
> > + * Make sure the group of events can be scheduled at once
> > + * on the PMU.
> > + */
> > +static bool tx2_uncore_validate_event_group(struct perf_event *event)
> > +{
> > + struct perf_event *sibling, *leader = event->group_leader;
> > + int counters = 0;
> > +
> > + if (event->group_leader == event)
> > + return true;
> > +
> > + if (!tx2_uncore_validate_event(event->pmu, leader, &counters))
> > + return false;
> > +
> > + for_each_sibling_event(sibling, leader) {
> > + if (!tx2_uncore_validate_event(event->pmu, sibling, &counters))
> > + return false;
> > + }
> > +
> > + if (!tx2_uncore_validate_event(event->pmu, event, &counters))
> > + return false;
> > +
> > + /*
> > + * If the group requires more counters than the HW has,
> > + * it cannot ever be scheduled.
> > + */
> > + return counters <= TX2_PMU_MAX_COUNTERS;
> > +}
> > +
> > +
> > +static int tx2_uncore_event_init(struct perf_event *event)
> > +{
> > + struct hw_perf_event *hwc = &event->hw;
> > + struct tx2_uncore_pmu *tx2_pmu;
> > +
> > + /* Test the event attr type check for PMU enumeration */
> > + if (event->attr.type != event->pmu->type)
> > + return -ENOENT;
> > +
> > + /*
> > + * SOC PMU counters are shared across all cores.
> > + * Therefore, it does not support per-process mode.
> > + * Also, it does not support event sampling mode.
> > + */
> > + if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
> > + return -EINVAL;
> > +
> > + /* SOC counters do not have usr/os/guest/host bits */
> > + if (event->attr.exclude_user || event->attr.exclude_kernel ||
> > + event->attr.exclude_host || event->attr.exclude_guest)
>
> exclude_hv and exclude_idle missing ?
>
> > + return -EINVAL;
> > +
> > + if (event->cpu < 0)
> > + return -EINVAL;
> > +
> > + tx2_pmu = pmu_to_tx2_pmu(event->pmu);
> > + if (tx2_pmu->cpu >= nr_cpu_ids)
> > + return -EINVAL;
> > + event->cpu = tx2_pmu->cpu;
> > +
> > + if (event->attr.config >= tx2_pmu->max_events)
> > + return -EINVAL;
> > +
> > + /* store event id */
> > + hwc->config = event->attr.config > +
> > + /* Validate the group */
> > + if (!tx2_uncore_validate_event_group(event))
> > + return -EINVAL;
> > +
> > + return 0;
> > +}
> > +
> > +static void tx2_uncore_event_start(struct perf_event *event, int flags)
> > +{
> > + struct hw_perf_event *hwc = &event->hw;
> > + struct tx2_uncore_pmu *tx2_pmu;
> > +
> > + hwc->state = 0;
> > + tx2_pmu = pmu_to_tx2_pmu(event->pmu);
> > +
> > + tx2_pmu->start_event(event, flags);
> > + perf_event_update_userpage(event);
> > +
> > + /* Start timer for first event */
> > + if (bitmap_weight(tx2_pmu->active_counters,
> > + tx2_pmu->max_counters) == 1) {
> > + hrtimer_start(&tx2_pmu->hrtimer,
> > + ns_to_ktime(tx2_pmu->hrtimer_interval),
> > + HRTIMER_MODE_REL_PINNED);
> > + }
> > +}
> > +
> > +static void tx2_uncore_event_stop(struct perf_event *event, int flags)
> > +{
> > + struct hw_perf_event *hwc = &event->hw;
> > + struct tx2_uncore_pmu *tx2_pmu;
> > +
> > + if (hwc->state & PERF_HES_UPTODATE)
> > + return;
> > +
> > + tx2_pmu = pmu_to_tx2_pmu(event->pmu);
> > + tx2_pmu->stop_event(event);
> > + WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
> > + hwc->state |= PERF_HES_STOPPED;
> > + if (flags & PERF_EF_UPDATE) {
> > + tx2_uncore_event_update(event);
> > + hwc->state |= PERF_HES_UPTODATE;
> > + }
> > +}
> > +
> > +static int tx2_uncore_event_add(struct perf_event *event, int flags)
> > +{
> > + struct hw_perf_event *hwc = &event->hw;
> > + struct tx2_uncore_pmu *tx2_pmu;
> > +
> > + tx2_pmu = pmu_to_tx2_pmu(event->pmu);
> > +
> > + /* Allocate a free counter */
> > + hwc->idx = alloc_counter(tx2_pmu);
> > + if (hwc->idx < 0)
> > + return -EAGAIN;
> > +
> > + tx2_pmu->events[hwc->idx] = event;
> > + /* set counter control and data registers base address */
> > + tx2_pmu->init_cntr_base(event, tx2_pmu);
> > +
> > + hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
> > + if (flags & PERF_EF_START)
> > + tx2_uncore_event_start(event, flags);
> > +
> > + return 0;
> > +}
> > +
> > +static void tx2_uncore_event_del(struct perf_event *event, int flags)
> > +{
> > + struct tx2_uncore_pmu *tx2_pmu = pmu_to_tx2_pmu(event->pmu);
> > + struct hw_perf_event *hwc = &event->hw;
> > +
> > + tx2_uncore_event_stop(event, PERF_EF_UPDATE);
> > +
> > + /* clear the assigned counter */
> > + free_counter(tx2_pmu, GET_COUNTERID(event));
> > +
> > + perf_event_update_userpage(event);
> > + tx2_pmu->events[hwc->idx] = NULL;
> > + hwc->idx = -1;
> > +}
> > +
> > +static void tx2_uncore_event_read(struct perf_event *event)
> > +{
> > + tx2_uncore_event_update(event);
> > +}
> > +
> > +static enum hrtimer_restart tx2_hrtimer_callback(struct hrtimer *timer)
> > +{
> > + struct tx2_uncore_pmu *tx2_pmu;
> > + int max_counters, idx;
> > + unsigned long irqflags;
> > +
> > + tx2_pmu = container_of(timer, struct tx2_uncore_pmu, hrtimer);
> > + max_counters = tx2_pmu->max_counters;
> > +
> > + if (bitmap_empty(tx2_pmu->active_counters, max_counters))
> > + return HRTIMER_NORESTART;
> > +
> > + raw_spin_lock_irqsave(&tx2_pmu->lock, irqflags);
> > +
> > + for_each_set_bit(idx, tx2_pmu->active_counters, max_counters) {
> > + struct perf_event *event = tx2_pmu->events[idx];
> > +
> > + tx2_uncore_event_update(event);
> > + }
> > + raw_spin_unlock_irqrestore(&tx2_pmu->lock, irqflags);
>
> What does this lock protect ? Can there be multiple active hrtimers for
> the same PMU ?
>
> > + hrtimer_forward_now(timer, ns_to_ktime(tx2_pmu->hrtimer_interval));
> > + return HRTIMER_RESTART;
> > +}
> > +
> > +static int tx2_uncore_pmu_register(
> > + struct tx2_uncore_pmu *tx2_pmu)
> > +{
> > + struct device *dev = tx2_pmu->dev;
> > + char *name = tx2_pmu->name;
> > +
> > + /* Perf event registration */
> > + tx2_pmu->pmu = (struct pmu) {
> > + .module = THIS_MODULE,
> > + .attr_groups = tx2_pmu->attr_groups,
> > + .task_ctx_nr = perf_invalid_context,
> > + .event_init = tx2_uncore_event_init,
> > + .add = tx2_uncore_event_add,
> > + .del = tx2_uncore_event_del,
> > + .start = tx2_uncore_event_start,
> > + .stop = tx2_uncore_event_stop,
> > + .read = tx2_uncore_event_read,
> > + };
> > +
> > + tx2_pmu->pmu.name = devm_kasprintf(dev, GFP_KERNEL,
> > + "%s", name);
> > +
> > + return perf_pmu_register(&tx2_pmu->pmu, tx2_pmu->pmu.name, -1);
> > +}
> > +
> > +static int tx2_uncore_pmu_add_dev(struct tx2_uncore_pmu *tx2_pmu)
> > +{
> > + int ret, cpu;
> > +
> > + cpu = cpumask_any_and(cpumask_of_node(tx2_pmu->node),
> > + cpu_online_mask);
> > +
> > + tx2_pmu->cpu = cpu;
> > + hrtimer_init(&tx2_pmu->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
> > + tx2_pmu->hrtimer.function = tx2_hrtimer_callback;
> > +
> > + ret = tx2_uncore_pmu_register(tx2_pmu);
> > + if (ret) {
> > + dev_err(tx2_pmu->dev, "%s PMU: Failed to init driver\n",
> > + tx2_pmu->name);
> > + return -ENODEV;
> > + }
> > +
> > + /* register hotplug callback for the pmu */
> > + ret = cpuhp_state_add_instance(
> > + CPUHP_AP_PERF_ARM_TX2_UNCORE_ONLINE,
> > + &tx2_pmu->hpnode);
> > + if (ret) {
> > + dev_err(tx2_pmu->dev, "Error %d registering hotplug", ret);
> > + return ret;
> > + }
> > +
> > + /* Add to list */
> > + list_add(&tx2_pmu->entry, &tx2_pmus);
> > +
> > + dev_dbg(tx2_pmu->dev, "%s PMU UNCORE registered\n",
> > + tx2_pmu->pmu.name);
> > + return ret;
> > +}
> > +
> > +static struct tx2_uncore_pmu *tx2_uncore_pmu_init_dev(struct device *dev,
> > + acpi_handle handle, struct acpi_device *adev, u32 type)
> > +{
> > + struct tx2_uncore_pmu *tx2_pmu;
> > + void __iomem *base;
> > + struct resource res;
> > + struct resource_entry *rentry;
> > + struct list_head list;
> > + int ret;
> > +
> > + INIT_LIST_HEAD(&list);
> > + ret = acpi_dev_get_resources(adev, &list, NULL, NULL);
> > + if (ret <= 0) {
> > + dev_err(dev, "failed to parse _CRS method, error %d\n", ret);
> > + return NULL;
> > + }
> > +
> > + list_for_each_entry(rentry, &list, node) {
> > + if (resource_type(rentry->res) == IORESOURCE_MEM) {
> > + res = *rentry->res;
> > + break;
> > + }
> > + }
> > +
> > + if (!rentry->res)
> > + return NULL;
> > +
> > + acpi_dev_free_resource_list(&list);
> > + base = devm_ioremap_resource(dev, &res);
> > + if (IS_ERR(base)) {
> > + dev_err(dev, "PMU type %d: Fail to map resource\n", type);
> > + return NULL;
> > + }
> > +
> > + tx2_pmu = devm_kzalloc(dev, sizeof(*tx2_pmu), GFP_KERNEL);
> > + if (!tx2_pmu)
> > + return NULL;
> > +
> > + tx2_pmu->dev = dev;
> > + tx2_pmu->type = type;
> > + tx2_pmu->base = base;
> > + tx2_pmu->node = dev_to_node(dev);
> > + INIT_LIST_HEAD(&tx2_pmu->entry);
> > + raw_spin_lock_init(&tx2_pmu->lock);
> > +
> > + switch (tx2_pmu->type) {
> > + case PMU_TYPE_L3C:
> > + tx2_pmu->max_counters = TX2_PMU_MAX_COUNTERS;
> > + tx2_pmu->prorate_factor = TX2_PMU_L3_TILES;
> > + tx2_pmu->max_events = L3_EVENT_MAX;
> > + tx2_pmu->hrtimer_interval = TX2_PMU_HRTIMER_INTERVAL;
> > + tx2_pmu->attr_groups = l3c_pmu_attr_groups;
> > + tx2_pmu->name = devm_kasprintf(dev, GFP_KERNEL,
> > + "uncore_l3c_%d", tx2_pmu->node);
> > + tx2_pmu->init_cntr_base = init_cntr_base_l3c;
> > + tx2_pmu->start_event = uncore_start_event_l3c;
> > + tx2_pmu->stop_event = uncore_stop_event_l3c;
> > + break;
> > + case PMU_TYPE_DMC:
> > + tx2_pmu->max_counters = TX2_PMU_MAX_COUNTERS;
> > + tx2_pmu->prorate_factor = TX2_PMU_DMC_CHANNELS;
> > + tx2_pmu->max_events = DMC_EVENT_MAX;
> > + tx2_pmu->hrtimer_interval = TX2_PMU_HRTIMER_INTERVAL;
> > + tx2_pmu->attr_groups = dmc_pmu_attr_groups;
> > + tx2_pmu->name = devm_kasprintf(dev, GFP_KERNEL,
> > + "uncore_dmc_%d", tx2_pmu->node);
> > + tx2_pmu->init_cntr_base = init_cntr_base_dmc;
> > + tx2_pmu->start_event = uncore_start_event_dmc;
> > + tx2_pmu->stop_event = uncore_stop_event_dmc;
> > + break;
> > + case PMU_TYPE_INVALID:
> > + devm_kfree(dev, tx2_pmu);
> > + return NULL;
> > + }
> > +
> > + return tx2_pmu;
> > +}
> > +
> > +static int tx2_uncore_pmu_online_cpu(unsigned int cpu,
> > + struct hlist_node *hpnode)
> > +{
> > + struct tx2_uncore_pmu *tx2_pmu;
> > +
> > + tx2_pmu = hlist_entry_safe(hpnode,
> > + struct tx2_uncore_pmu, hpnode);
> > +
> > + /* Pick this CPU, If there is no CPU/PMU association and both are
> > + * from same node.
> > + */
> > + if ((tx2_pmu->cpu >= nr_cpu_ids) &&
> > + (tx2_pmu->node == cpu_to_node(cpu)))
> > + tx2_pmu->cpu = cpu;
> > +
> > + return 0;
> > +}
> > +
> > +static int tx2_uncore_pmu_offline_cpu(unsigned int cpu,
> > + struct hlist_node *hpnode)
> > +{
> > + int new_cpu;
> > + struct tx2_uncore_pmu *tx2_pmu;
> > + struct cpumask cpu_online_mask_temp;
> > +
> > + tx2_pmu = hlist_entry_safe(hpnode,
> > + struct tx2_uncore_pmu, hpnode);
> > +
> > + if (cpu != tx2_pmu->cpu)
> > + return 0;
> > +
> > + hrtimer_cancel(&tx2_pmu->hrtimer);
> > + cpumask_copy(&cpu_online_mask_temp, cpu_online_mask);
> > + cpumask_clear_cpu(cpu, &cpu_online_mask_temp);
> > + new_cpu = cpumask_any_and(
> > + cpumask_of_node(tx2_pmu->node),
> > + &cpu_online_mask_temp);
> > +
> > + tx2_pmu->cpu = new_cpu;
> > + if (new_cpu >= nr_cpu_ids)
> > + return 0;
> > + perf_pmu_migrate_context(&tx2_pmu->pmu, cpu, new_cpu);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct acpi_device_id tx2_uncore_acpi_match[] = {
> > + {"CAV901C", 0},
> > + {},
> > +};
> > +MODULE_DEVICE_TABLE(acpi, tx2_uncore_acpi_match);
> > +
> > +static int tx2_uncore_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + acpi_handle handle;
> > + acpi_status status;
> > +
> > + set_dev_node(dev, acpi_get_node(ACPI_HANDLE(dev)));
> > +
> > + if (!has_acpi_companion(dev))
> > + return -ENODEV;
> > +
> > + handle = ACPI_HANDLE(dev);
> > + if (!handle)
> > + return -EINVAL;
> > +
> > + /* Walk through the tree for all PMU UNCORE devices */
> > + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
> > + tx2_uncore_pmu_add,
> > + NULL, dev, NULL);
> > + if (ACPI_FAILURE(status)) {
> > + dev_err(dev, "failed to probe PMU devices\n");
> > + return_ACPI_STATUS(status);
> > + }
> > +
> > + dev_info(dev, "node%d: pmu uncore registered\n", dev_to_node(dev));
> > + return 0;
> > +}
> > +
> > +static int tx2_uncore_remove(struct platform_device *pdev)
> > +{
> > + struct tx2_uncore_pmu *tx2_pmu, *temp;
> > + struct device *dev = &pdev->dev;
> > +
> > + if (!list_empty(&tx2_pmus)) {
> > + list_for_each_entry_safe(tx2_pmu, temp, &tx2_pmus, entry) {
> > + if (tx2_pmu->node == dev_to_node(dev)) {
> > + cpuhp_state_remove_instance_nocalls(
> > + CPUHP_AP_PERF_ARM_TX2_UNCORE_ONLINE,
> > + &tx2_pmu->hpnode);
> > + perf_pmu_unregister(&tx2_pmu->pmu);
> > + list_del(&tx2_pmu->entry);
> > + }
> > + }
> > + }
> > + return 0;
> > +}
> > +
> > +static struct platform_driver tx2_uncore_driver = {
> > + .driver = {
> > + .name = "tx2-uncore-pmu",
> > + .acpi_match_table = ACPI_PTR(tx2_uncore_acpi_match),
> > + },
> > + .probe = tx2_uncore_probe,
> > + .remove = tx2_uncore_remove,
> > +};
> > +
> > +static int __init tx2_uncore_driver_init(void)
> > +{
> > + int ret;
> > +
> > + ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_ARM_TX2_UNCORE_ONLINE,
> > + "perf/tx2/uncore:online",
> > + tx2_uncore_pmu_online_cpu,
> > + tx2_uncore_pmu_offline_cpu);
> > + if (ret) {
> > + pr_err("TX2 PMU: setup hotplug failed(%d)\n", ret);
> > + return ret;
> > + }
> > + ret = platform_driver_register(&tx2_uncore_driver);
> > + if (ret)
> > + cpuhp_remove_multi_state(CPUHP_AP_PERF_ARM_TX2_UNCORE_ONLINE);
> > +
> > + return ret;
> > +}
> > +module_init(tx2_uncore_driver_init);
> > +
> > +static void __exit tx2_uncore_driver_exit(void)
> > +{
> > + platform_driver_unregister(&tx2_uncore_driver);
> > + cpuhp_remove_multi_state(CPUHP_AP_PERF_ARM_TX2_UNCORE_ONLINE);
> > +}
> > +module_exit(tx2_uncore_driver_exit);
> > +
> > +MODULE_DESCRIPTION("ThunderX2 UNCORE PMU driver");
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_AUTHOR("Ganapatrao Kulkarni <gkulkarni@xxxxxxxxxx>");
> > diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> > index caf40ad0bbc6..2c13dc2f765d 100644
> > --- a/include/linux/cpuhotplug.h
> > +++ b/include/linux/cpuhotplug.h
> > @@ -163,6 +163,7 @@ enum cpuhp_state {
> > CPUHP_AP_PERF_ARM_L2X0_ONLINE,
> > CPUHP_AP_PERF_ARM_QCOM_L2_ONLINE,
> > CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE,
> > + CPUHP_AP_PERF_ARM_TX2_UNCORE_ONLINE,
> > CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE,
> > CPUHP_AP_PERF_POWERPC_CORE_IMC_ONLINE,
> > CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE,
> >
>
> Suzuki
Thanks,
Ganapat