Hi Ganpat,

On 05/12/2018 10:59, 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.

Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulka...@cavium.com>
---
  drivers/perf/Kconfig         |   9 +
  drivers/perf/Makefile        |   1 +
  drivers/perf/thunderx2_pmu.c | 861 +++++++++++++++++++++++++++++++++++
  include/linux/cpuhotplug.h   |   1 +
  4 files changed, 872 insertions(+)
  create mode 100644 drivers/perf/thunderx2_pmu.c

--- /dev/null
+++ b/drivers/perf/thunderx2_pmu.c
@@ -0,0 +1,861 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * CAVIUM THUNDERX2 SoC PMU UNCORE
+ * Copyright (C) 2018 Cavium Inc.
+ * Author: Ganapatrao Kulkarni <gkulka...@cavium.com>
+ */
+
+#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) & 0x1f)
+#define GET_COUNTERID(ev)              ((ev->hw.idx) & 0x3)
+ /* 1 byte per counter(4 counters).
+  * Event id is encoded in bits [5:1] of a byte,
+  */
+#define DMC_EVENT_CFG(idx, val)                ((val) << (((idx) * 8) + 1))
+
+#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;

minor nit:

The alignment of the fields are pretty inconsistent. e.g,
u32 is followed by tabs and the rest are not. Please keep it
consistent.

+       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;
+       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);
+}
+
+PMU_FORMAT_ATTR(event, "config:0-4");
+
+static struct attribute *l3c_pmu_format_attrs[] = {
+       &format_attr_event.attr,
+       NULL,
+};
+
+static struct attribute *dmc_pmu_format_attrs[] = {
+       &format_attr_event.attr,
+       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, "event=0x%lx\n", (unsigned long) eattr->var);
+}
+
+#define TX2_EVENT_ATTR(name, config) \
+       PMU_EVENT_ATTR(name, tx2_pmu_event_attr_##name, \
+                       config, tx2_pmu_event_show)
+
+TX2_EVENT_ATTR(read_request, L3_EVENT_READ_REQ);
+TX2_EVENT_ATTR(writeback_request, L3_EVENT_WRITEBACK_REQ);
+TX2_EVENT_ATTR(inv_nwrite_request, L3_EVENT_INV_N_WRITE_REQ);
+TX2_EVENT_ATTR(inv_request, L3_EVENT_INV_REQ);
+TX2_EVENT_ATTR(evict_request, L3_EVENT_EVICT_REQ);
+TX2_EVENT_ATTR(inv_nwrite_hit, L3_EVENT_INV_N_WRITE_HIT);
+TX2_EVENT_ATTR(inv_hit, L3_EVENT_INV_HIT);
+TX2_EVENT_ATTR(read_hit, L3_EVENT_READ_HIT);
+
+static struct attribute *l3c_pmu_events_attrs[] = {
+       &tx2_pmu_event_attr_read_request.attr.attr,
+       &tx2_pmu_event_attr_writeback_request.attr.attr,
+       &tx2_pmu_event_attr_inv_nwrite_request.attr.attr,
+       &tx2_pmu_event_attr_inv_request.attr.attr,
+       &tx2_pmu_event_attr_evict_request.attr.attr,
+       &tx2_pmu_event_attr_inv_nwrite_hit.attr.attr,
+       &tx2_pmu_event_attr_inv_hit.attr.attr,
+       &tx2_pmu_event_attr_read_hit.attr.attr,
+       NULL,
+};
+
+TX2_EVENT_ATTR(cnt_cycles, DMC_EVENT_COUNT_CYCLES);
+TX2_EVENT_ATTR(write_txns, DMC_EVENT_WRITE_TXNS);
+TX2_EVENT_ATTR(data_transfers, DMC_EVENT_DATA_TRANSFERS);
+TX2_EVENT_ATTR(read_txns, DMC_EVENT_READ_TXNS);
+
+static struct attribute *dmc_pmu_events_attrs[] = {
+       &tx2_pmu_event_attr_cnt_cycles.attr.attr,
+       &tx2_pmu_event_attr_write_txns.attr.attr,
+       &tx2_pmu_event_attr_data_transfers.attr.attr,
+       &tx2_pmu_event_attr_read_txns.attr.attr,
+       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)
+{
+       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))
+                       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;

nit: alignment.

Otherwise looks good to me.
FWIW, with the above nits fixed:

Reviewed-by: Suzuki K Poulose <suzuki.poul...@arm.com>

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