Message-ID: <20240216000837.1868917-3-samuel.holland@sifive.com>
Date: Thu, 15 Feb 2024 16:08:14 -0800
From: Samuel Holland <samuel.holland@...ive.com>
To: Will Deacon <will@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Eric Lin <eric.lin@...ive.com>,
	Conor Dooley <conor@...nel.org>
Cc: Palmer Dabbelt <palmer@...belt.com>,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Paul Walmsley <paul.walmsley@...ive.com>,
	linux-riscv@...ts.infradead.org,
	Rob Herring <robh+dt@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	linux-arm-kernel@...ts.infradead.org,
	Samuel Holland <samuel.holland@...ive.com>
Subject: [PATCH v1 2/6] drivers/perf: Add SiFive Composable Cache PMU driver

From: Eric Lin <eric.lin@...ive.com>

Add a driver for the PMU found in the SiFive Composable Cache
controller. This PMU provides a configurable number of counters and a
variety of events. Events are grouped into sets. Each counter can count
events from only one set at a time; however, it can count any number of
events within that set simultaneously. The PMU hardware does not provide
an overflow interrupt or a way to atomically control groups of counters.

Some events can be filtered further by client ID (e.g. CPU or external
DMA master). That functionality is not supported by this driver.

This driver further assumes that a single Composable Cache instance is
shared by all CPUs in the system.

Example usage:

$ perf stat -a -e sifive_ccache_pmu/inner_acquire_block_btot/,
		  sifive_ccache_pmu/inner_acquire_block_hit/,
		  sifive_ccache_pmu/inner_acquire_block_ntob/ ls

 Performance counter stats for 'system wide':

               542      sifive_ccache_pmu/inner_acquire_block_btot/
             22081      sifive_ccache_pmu/inner_acquire_block_hit/
             22006      sifive_ccache_pmu/inner_acquire_block_ntob/

       0.064672432 seconds time elapsed

Example using numeric event selectors:

$ perf stat -a -e sifive_ccache_pmu/event=0x10001/,
		  sifive_ccache_pmu/event=0x2002/,
		  sifive_ccache_pmu/event=0x4001/ ls

 Performance counter stats for 'system wide':

               478      sifive_ccache_pmu/event=0x10001/
              4717      sifive_ccache_pmu/event=0x2002/
             44966      sifive_ccache_pmu/event=0x4001/

       0.111027326 seconds time elapsed

Signed-off-by: Eric Lin <eric.lin@...ive.com>
Co-developed-by: Samuel Holland <samuel.holland@...ive.com>
Signed-off-by: Samuel Holland <samuel.holland@...ive.com>
---

 drivers/perf/Kconfig             |   9 +
 drivers/perf/Makefile            |   1 +
 drivers/perf/sifive_ccache_pmu.c | 577 +++++++++++++++++++++++++++++++
 include/linux/cpuhotplug.h       |   1 +
 4 files changed, 588 insertions(+)
 create mode 100644 drivers/perf/sifive_ccache_pmu.c

diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index ec6e0d9194a1..b4e4db7424b4 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -155,6 +155,15 @@ config QCOM_L3_PMU
 	   Adds the L3 cache PMU into the perf events subsystem for
 	   monitoring L3 cache events.
 
+config SIFIVE_CCACHE_PMU
+	tristate "SiFive Composable Cache PMU"
+	depends on RISCV || COMPILE_TEST
+	help
+	  Support for the Composable Cache performance monitoring unit (PMU) on
+	  SiFive platforms. The Composable Cache PMU provides up to 64 counters
+	  for measuring whole-system L2/L3 cache performance using the perf
+	  events subsystem.
+
 config THUNDERX2_PMU
 	tristate "Cavium ThunderX2 SoC PMU UNCORE"
 	depends on ARCH_THUNDER2 || COMPILE_TEST
diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
index a06338e3401c..51ef5f50ace4 100644
--- a/drivers/perf/Makefile
+++ b/drivers/perf/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
 obj-$(CONFIG_RISCV_PMU) += riscv_pmu.o
 obj-$(CONFIG_RISCV_PMU_LEGACY) += riscv_pmu_legacy.o
 obj-$(CONFIG_RISCV_PMU_SBI) += riscv_pmu_sbi.o
+obj-$(CONFIG_SIFIVE_CCACHE_PMU) += sifive_ccache_pmu.o
 obj-$(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/sifive_ccache_pmu.c b/drivers/perf/sifive_ccache_pmu.c
new file mode 100644
index 000000000000..8c9ef0d09f48
--- /dev/null
+++ b/drivers/perf/sifive_ccache_pmu.c
@@ -0,0 +1,577 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SiFive Composable Cache PMU driver
+ *
+ * Copyright (C) 2022-2024 SiFive, Inc.
+ * Copyright (C) Eric Lin <eric.lin@...ive.com>
+ *
+ */
+
+#include <linux/cpuhotplug.h>
+#include <linux/cpumask.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/perf_event.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#define CCACHE_SELECT_OFFSET		0x2000
+#define CCACHE_CLIENT_FILTER_OFFSET	0x2800
+#define CCACHE_COUNTER_OFFSET		0x3000
+
+#define CCACHE_PMU_MAX_COUNTERS		64
+
+struct sifive_ccache_pmu {
+	struct pmu			pmu;
+	struct hlist_node		node;
+	struct notifier_block		cpu_pm_nb;
+	void __iomem			*base;
+	DECLARE_BITMAP(used_mask, CCACHE_PMU_MAX_COUNTERS);
+	unsigned int			cpu;
+	int				n_counters;
+	struct perf_event		*events[] __counted_by(n_counters);
+};
+
+#define to_ccache_pmu(p) (container_of(p, struct sifive_ccache_pmu, pmu))
+
+#ifndef readq
+static inline u64 readq(void __iomem *addr)
+{
+	return readl(addr) | (((u64)readl(addr + 4)) << 32);
+}
+#endif
+
+#ifndef writeq
+static inline void writeq(u64 v, void __iomem *addr)
+{
+	writel(lower_32_bits(v), addr);
+	writel(upper_32_bits(v), addr + 4);
+}
+#endif
+
+/*
+ * sysfs attributes
+ *
+ * We export:
+ * - cpumask, used by perf user space and other tools to know on which CPUs to create events
+ * - events, used by perf user space and other tools to create events symbolically, e.g.:
+ *     perf stat -a -e sifive_ccache_pmu/event=inner_put_partial_data_hit/ ls
+ *     perf stat -a -e sifive_ccache_pmu/event=0x101/ ls
+ * - formats, used by perf user space and other tools to configure events
+ */
+
+/* cpumask */
+static ssize_t cpumask_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct sifive_ccache_pmu *ccache_pmu = dev_get_drvdata(dev);
+
+	if (ccache_pmu->cpu >= nr_cpu_ids)
+		return 0;
+
+	return sysfs_emit(buf, "%d\n", ccache_pmu->cpu);
+};
+
+static DEVICE_ATTR_RO(cpumask);
+
+static struct attribute *sifive_ccache_pmu_cpumask_attrs[] = {
+	&dev_attr_cpumask.attr,
+	NULL,
+};
+
+static const struct attribute_group sifive_ccache_pmu_cpumask_group = {
+	.attrs = sifive_ccache_pmu_cpumask_attrs,
+};
+
+/* events */
+static ssize_t sifive_ccache_pmu_event_show(struct device *dev, struct device_attribute *attr,
+					    char *page)
+{
+	struct perf_pmu_events_attr *pmu_attr;
+
+	pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
+	return sysfs_emit(page, "event=0x%02llx\n", pmu_attr->id);
+}
+
+#define SET_EVENT_SELECT(_event, _set)	(BIT_ULL((_event) + 8) | (_set))
+#define CCACHE_PMU_EVENT_ATTR(_name, _event, _set) \
+	PMU_EVENT_ATTR_ID(_name, sifive_ccache_pmu_event_show, SET_EVENT_SELECT(_event, _set))
+
+enum ccache_pmu_event_set1 {
+	INNER_PUT_FULL_DATA = 0,
+	INNER_PUT_PARTIAL_DATA,
+	INNER_ATOMIC_DATA,
+	INNER_GET,
+	INNER_PREFETCH_READ,
+	INNER_PREFETCH_WRITE,
+	INNER_ACQUIRE_BLOCK_NTOB,
+	INNER_ACQUIRE_BLOCK_NTOT,
+	INNER_ACQUIRE_BLOCK_BTOT,
+	INNER_ACQUIRE_PERM_NTOT,
+	INNER_ACQUIRE_PERM_BTOT,
+	INNER_RELEASE_TTOB,
+	INNER_RELEASE_TTON,
+	INNER_RELEASE_BTON,
+	INNER_RELEASE_DATA_TTOB,
+	INNER_RELEASE_DATA_TTON,
+	INNER_RELEASE_DATA_BTON,
+	OUTER_PROBE_BLOCK_TOT,
+	OUTER_PROBE_BLOCK_TOB,
+	OUTER_PROBE_BLOCK_TON,
+	CCACHE_PMU_MAX_EVENT1_IDX
+};
+
+enum ccache_pmu_event_set2 {
+	INNER_PUT_FULL_DATA_HIT = 0,
+	INNER_PUT_PARTIAL_DATA_HIT,
+	INNER_ATOMIC_DATA_HIT,
+	INNER_GET_HIT,
+	INNER_PREFETCH_HIT,
+	INNER_ACQUIRE_BLOCK_HIT,
+	INNER_ACQUIRE_PERM_HIT,
+	INNER_RELEASE_HIT,
+	INNER_RELEASE_DATA_HIT,
+	OUTER_PROBE_HIT,
+	INNER_PUT_FULL_DATA_HIT_SHARED,
+	INNER_PUT_PARTIAL_DATA_HIT_SHARED,
+	INNER_ATOMIC_DATA_HIT_SHARED,
+	INNER_GET_HIT_SHARED,
+	INNER_PREFETCH_HIT_SHARED,
+	INNER_ACQUIRE_BLOCK_HIT_SHARED,
+	INNER_ACQUIRE_PERM_HIT_SHARED,
+	OUTER_PROBE_HIT_SHARED,
+	OUTER_PROBE_HIT_DIRTY,
+	CCACHE_PMU_MAX_EVENT2_IDX
+};
+
+enum ccache_pmu_event_set3 {
+	OUTER_ACQUIRE_BLOCK_NTOB_MISS = 0,
+	OUTER_ACQUIRE_BLOCK_NTOT_MISS,
+	OUTER_ACQUIRE_BLOCK_BTOT_MISS,
+	OUTER_ACQUIRE_PERM_NTOT_MISS,
+	OUTER_ACQUIRE_PERM_BTOT_MISS,
+	OUTER_RELEASE_TTOB_EVICTION,
+	OUTER_RELEASE_TTON_EVICTION,
+	OUTER_RELEASE_BTON_EVICTION,
+	OUTER_RELEASE_DATA_TTOB_NOT_APPLICABLE,
+	OUTER_RELEASE_DATA_TTON_DIRTY_EVICTION,
+	OUTER_RELEASE_DATA_BTON_NOT_APPLICABLE,
+	INNER_PROBE_BLOCK_TOT_CODE_MISS_HITS_OTHER_HARTS,
+	INNER_PROBE_BLOCK_TOB_LOAD_MISS_HITS_OTHER_HARTS,
+	INNER_PROBE_BLOCK_TON_STORE_MISS_HITS_OTHER_HARTS,
+	CCACHE_PMU_MAX_EVENT3_IDX
+};
+
+enum ccache_pmu_event_set4 {
+	INNER_HINT_HITS_INFLIGHT_MISS = 0,
+	CCACHE_PMU_MAX_EVENT4_IDX
+};
+
+static struct attribute *sifive_ccache_pmu_events[] = {
+	/*  pmEventSelect1 */
+	CCACHE_PMU_EVENT_ATTR(inner_put_full_data, INNER_PUT_FULL_DATA, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_put_partial_data, INNER_PUT_PARTIAL_DATA, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_atomic_data, INNER_ATOMIC_DATA, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_get, INNER_GET, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_prefetch_read, INNER_PREFETCH_READ, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_prefetch_write, INNER_PREFETCH_WRITE, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_acquire_block_ntob, INNER_ACQUIRE_BLOCK_NTOB, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_acquire_block_ntot, INNER_ACQUIRE_BLOCK_NTOT, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_acquire_block_btot, INNER_ACQUIRE_BLOCK_BTOT, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_acquire_perm_ntot, INNER_ACQUIRE_PERM_NTOT, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_acquire_perm_btot, INNER_ACQUIRE_PERM_BTOT, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_release_ttob, INNER_RELEASE_TTOB, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_release_tton, INNER_RELEASE_TTON, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_release_bton, INNER_RELEASE_BTON, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_release_data_ttob, INNER_RELEASE_DATA_TTOB, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_release_data_tton, INNER_RELEASE_DATA_TTON, 1),
+	CCACHE_PMU_EVENT_ATTR(inner_release_data_bton, INNER_RELEASE_DATA_BTON, 1),
+	CCACHE_PMU_EVENT_ATTR(outer_probe_block_tot, OUTER_PROBE_BLOCK_TOT, 1),
+	CCACHE_PMU_EVENT_ATTR(outer_probe_block_tob, OUTER_PROBE_BLOCK_TOB, 1),
+	CCACHE_PMU_EVENT_ATTR(outer_probe_block_ton, OUTER_PROBE_BLOCK_TON, 1),
+
+	/*  pmEventSelect2 */
+	CCACHE_PMU_EVENT_ATTR(inner_put_full_data_hit, INNER_PUT_FULL_DATA_HIT, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_put_partial_data_hit, INNER_PUT_PARTIAL_DATA_HIT, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_atomic_data_hit, INNER_ATOMIC_DATA_HIT, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_get_hit, INNER_GET_HIT, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_prefetch_hit, INNER_PREFETCH_HIT, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_acquire_block_hit, INNER_ACQUIRE_BLOCK_HIT, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_acquire_perm_hit, INNER_ACQUIRE_PERM_HIT, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_release_hit, INNER_RELEASE_HIT, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_release_data_hit, INNER_RELEASE_DATA_HIT, 2),
+	CCACHE_PMU_EVENT_ATTR(outer_probe_hit, OUTER_PROBE_HIT, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_put_full_data_hit_shared, INNER_PUT_FULL_DATA_HIT_SHARED, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_put_partial_data_hit_shared,
+			      INNER_PUT_PARTIAL_DATA_HIT_SHARED, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_atomic_data_hit_shared, INNER_ATOMIC_DATA_HIT_SHARED, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_get_hit_shared, INNER_GET_HIT_SHARED, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_prefetch_hit_shared, INNER_PREFETCH_HIT_SHARED, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_acquire_block_hit_shared, INNER_ACQUIRE_BLOCK_HIT_SHARED, 2),
+	CCACHE_PMU_EVENT_ATTR(inner_acquire_perm_hit_shared, INNER_ACQUIRE_PERM_HIT_SHARED, 2),
+	CCACHE_PMU_EVENT_ATTR(outer_probe_hit_shared, OUTER_PROBE_HIT_SHARED, 2),
+	CCACHE_PMU_EVENT_ATTR(outer_probe_hit_dirty, OUTER_PROBE_HIT_DIRTY, 2),
+
+	/*  pmEventSelect3 */
+	CCACHE_PMU_EVENT_ATTR(outer_acquire_block_ntob_miss, OUTER_ACQUIRE_BLOCK_NTOB_MISS, 3),
+	CCACHE_PMU_EVENT_ATTR(outer_acquire_block_ntot_miss, OUTER_ACQUIRE_BLOCK_NTOT_MISS, 3),
+	CCACHE_PMU_EVENT_ATTR(outer_acquire_block_btot_miss, OUTER_ACQUIRE_BLOCK_BTOT_MISS, 3),
+	CCACHE_PMU_EVENT_ATTR(outer_acquire_perm_ntot_miss, OUTER_ACQUIRE_PERM_NTOT_MISS, 3),
+	CCACHE_PMU_EVENT_ATTR(outer_acquire_perm_btot_miss, OUTER_ACQUIRE_PERM_BTOT_MISS, 3),
+	CCACHE_PMU_EVENT_ATTR(outer_release_ttob_eviction, OUTER_RELEASE_TTOB_EVICTION, 3),
+	CCACHE_PMU_EVENT_ATTR(outer_release_tton_eviction, OUTER_RELEASE_TTON_EVICTION, 3),
+	CCACHE_PMU_EVENT_ATTR(outer_release_bton_eviction, OUTER_RELEASE_BTON_EVICTION, 3),
+	CCACHE_PMU_EVENT_ATTR(outer_release_data_ttob_not_applicable,
+			      OUTER_RELEASE_DATA_TTOB_NOT_APPLICABLE, 3),
+	CCACHE_PMU_EVENT_ATTR(outer_release_data_tton_dirty_eviction,
+			      OUTER_RELEASE_DATA_TTON_DIRTY_EVICTION, 3),
+	CCACHE_PMU_EVENT_ATTR(outer_release_data_bton_not_applicable,
+			      OUTER_RELEASE_DATA_BTON_NOT_APPLICABLE, 3),
+	CCACHE_PMU_EVENT_ATTR(inner_probe_block_tot_code_miss_hits_other_harts,
+			      INNER_PROBE_BLOCK_TOT_CODE_MISS_HITS_OTHER_HARTS, 3),
+	CCACHE_PMU_EVENT_ATTR(inner_probe_block_tob_load_miss_hits_other_harts,
+			      INNER_PROBE_BLOCK_TOB_LOAD_MISS_HITS_OTHER_HARTS, 3),
+	CCACHE_PMU_EVENT_ATTR(inner_probe_block_ton_store_miss_hits_other_harts,
+			      INNER_PROBE_BLOCK_TON_STORE_MISS_HITS_OTHER_HARTS, 3),
+
+	/*  pm_event_select4 */
+	CCACHE_PMU_EVENT_ATTR(inner_hint_hits_inflight_miss, INNER_HINT_HITS_INFLIGHT_MISS, 4),
+	NULL
+};
+
+static struct attribute_group sifive_ccache_pmu_events_group = {
+	.name = "events",
+	.attrs = sifive_ccache_pmu_events,
+};
+
+/* formats */
+PMU_FORMAT_ATTR(event, "config:0-63");
+
+static struct attribute *sifive_ccache_pmu_formats[] = {
+	&format_attr_event.attr,
+	NULL,
+};
+
+static struct attribute_group sifive_ccache_pmu_format_group = {
+	.name = "format",
+	.attrs = sifive_ccache_pmu_formats,
+};
+
+/*
+ * Per PMU device attribute groups
+ */
+
+static const struct attribute_group *sifive_ccache_pmu_attr_grps[] = {
+	&sifive_ccache_pmu_cpumask_group,
+	&sifive_ccache_pmu_events_group,
+	&sifive_ccache_pmu_format_group,
+	NULL,
+};
+
+/*
+ * Event Initialization
+ */
+
+static int sifive_ccache_pmu_event_init(struct perf_event *event)
+{
+	struct sifive_ccache_pmu *ccache_pmu = to_ccache_pmu(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+	u64 config = event->attr.config;
+	u64 ev_type = config >> 8;
+	u64 set = config & 0xff;
+
+	/* Check if this is a valid set and event */
+	switch (set) {
+	case 1:
+		if (ev_type >= BIT_ULL(CCACHE_PMU_MAX_EVENT1_IDX))
+			return -ENOENT;
+		break;
+	case 2:
+		if (ev_type >= BIT_ULL(CCACHE_PMU_MAX_EVENT2_IDX))
+			return -ENOENT;
+		break;
+	case 3:
+		if (ev_type >= BIT_ULL(CCACHE_PMU_MAX_EVENT3_IDX))
+			return -ENOENT;
+		break;
+	case 4:
+		if (ev_type >= BIT_ULL(CCACHE_PMU_MAX_EVENT4_IDX))
+			return -ENOENT;
+		break;
+	default:
+		return -ENOENT;
+	}
+
+	/* Do not allocate the hardware counter yet */
+	hwc->idx = -1;
+	hwc->config = config;
+
+	event->cpu = ccache_pmu->cpu;
+
+	return 0;
+}
+
+/*
+ * pmu->read: read and update the counter
+ */
+static void sifive_ccache_pmu_read(struct perf_event *event)
+{
+	struct hw_perf_event *hwc = &event->hw;
+	u64 prev_raw_count, new_raw_count;
+	u64 oldval;
+
+	do {
+		prev_raw_count = local64_read(&hwc->prev_count);
+		new_raw_count = readq((void *)hwc->event_base);
+
+		oldval = local64_cmpxchg(&hwc->prev_count, prev_raw_count, new_raw_count);
+	} while (oldval != prev_raw_count);
+
+	local64_add(new_raw_count - prev_raw_count, &event->count);
+}
+
+/*
+ * State transition functions:
+ *
+ * start()/stop() & add()/del()
+ */
+
+/*
+ * pmu->start: start the event
+ */
+static void sifive_ccache_pmu_start(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED)))
+		return;
+
+	hwc->state = 0;
+
+	/* Set initial value to 0 */
+	local64_set(&hwc->prev_count, 0);
+	writeq(0, (void *)hwc->event_base);
+
+	/* Enable this counter to count events */
+	writeq(hwc->config, (void *)hwc->config_base);
+}
+
+/*
+ * pmu->stop: stop the counter
+ */
+static void sifive_ccache_pmu_stop(struct perf_event *event, int flags)
+{
+	struct hw_perf_event *hwc = &event->hw;
+
+	if (hwc->state & PERF_HES_STOPPED)
+		return;
+
+	/* Disable this counter to count events */
+	writeq(0, (void *)hwc->config_base);
+	sifive_ccache_pmu_read(event);
+
+	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
+}
+
+/*
+ * pmu->add: add the event to the PMU
+ */
+static int sifive_ccache_pmu_add(struct perf_event *event, int flags)
+{
+	struct sifive_ccache_pmu *ccache_pmu = to_ccache_pmu(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+	int idx;
+
+	/* Find an available counter idx to use for this event */
+	do {
+		idx = find_first_zero_bit(ccache_pmu->used_mask, ccache_pmu->n_counters);
+		if (idx >= ccache_pmu->n_counters)
+			return -EAGAIN;
+	} while (test_and_set_bit(idx, ccache_pmu->used_mask));
+
+	hwc->config_base = (unsigned long)ccache_pmu->base + CCACHE_SELECT_OFFSET + 8 * idx;
+	hwc->event_base = (unsigned long)ccache_pmu->base + CCACHE_COUNTER_OFFSET + 8 * idx;
+	hwc->idx = idx;
+	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
+
+	ccache_pmu->events[idx] = event;
+
+	if (flags & PERF_EF_START)
+		sifive_ccache_pmu_start(event, PERF_EF_RELOAD);
+
+	perf_event_update_userpage(event);
+
+	return 0;
+}
+
+/*
+ * pmu->del: delete the event from the PMU
+ */
+static void sifive_ccache_pmu_del(struct perf_event *event, int flags)
+{
+	struct sifive_ccache_pmu *ccache_pmu = to_ccache_pmu(event->pmu);
+	struct hw_perf_event *hwc = &event->hw;
+	int idx = hwc->idx;
+
+	/* Stop and release this counter */
+	sifive_ccache_pmu_stop(event, PERF_EF_UPDATE);
+
+	ccache_pmu->events[idx] = NULL;
+	clear_bit(idx, ccache_pmu->used_mask);
+
+	perf_event_update_userpage(event);
+}
+
+/*
+ * Driver initialization
+ */
+
+static void sifive_ccache_pmu_hw_init(const struct sifive_ccache_pmu *ccache_pmu)
+{
+	/* Disable the client filter (not supported by this driver) */
+	writeq(0, ccache_pmu->base + CCACHE_CLIENT_FILTER_OFFSET);
+}
+
+static int sifive_ccache_pmu_online_cpu(unsigned int cpu, struct hlist_node *node)
+{
+	struct sifive_ccache_pmu *ccache_pmu =
+		hlist_entry_safe(node, struct sifive_ccache_pmu, node);
+
+	if (ccache_pmu->cpu >= nr_cpu_ids)
+		ccache_pmu->cpu = cpu;
+
+	return 0;
+}
+
+static int sifive_ccache_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
+{
+	struct sifive_ccache_pmu *ccache_pmu =
+		hlist_entry_safe(node, struct sifive_ccache_pmu, node);
+
+	/* Do nothing if this CPU does not own the events */
+	if (cpu != ccache_pmu->cpu)
+		return 0;
+
+	/* Pick a random online CPU */
+	ccache_pmu->cpu = cpumask_any_but(cpu_online_mask, cpu);
+	if (ccache_pmu->cpu >= nr_cpu_ids)
+		return 0;
+
+	/* Migrate PMU events from this CPU to the target CPU */
+	perf_pmu_migrate_context(&ccache_pmu->pmu, cpu, ccache_pmu->cpu);
+
+	return 0;
+}
+
+static int sifive_ccache_pmu_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct sifive_ccache_pmu *ccache_pmu;
+	u32 n_counters;
+	int ret;
+
+	/* Instances without a sifive,perfmon-counters property do not contain a PMU */
+	ret = device_property_read_u32(dev, "sifive,perfmon-counters", &n_counters);
+	if (ret || !n_counters)
+		return -ENODEV;
+
+	ccache_pmu = devm_kzalloc(dev, struct_size(ccache_pmu, events, n_counters), GFP_KERNEL);
+	if (!ccache_pmu)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, ccache_pmu);
+
+	ccache_pmu->pmu = (struct pmu) {
+		.parent		= dev,
+		.attr_groups	= sifive_ccache_pmu_attr_grps,
+		.capabilities	= PERF_PMU_CAP_NO_EXCLUDE | PERF_PMU_CAP_NO_INTERRUPT,
+		.task_ctx_nr	= perf_invalid_context,
+		.event_init	= sifive_ccache_pmu_event_init,
+		.add		= sifive_ccache_pmu_add,
+		.del		= sifive_ccache_pmu_del,
+		.start		= sifive_ccache_pmu_start,
+		.stop		= sifive_ccache_pmu_stop,
+		.read		= sifive_ccache_pmu_read,
+	};
+	ccache_pmu->cpu = nr_cpu_ids;
+	ccache_pmu->n_counters = n_counters;
+
+	ccache_pmu->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(ccache_pmu->base))
+		return PTR_ERR(ccache_pmu->base);
+
+	sifive_ccache_pmu_hw_init(ccache_pmu);
+
+	ret = cpuhp_state_add_instance(CPUHP_AP_PERF_RISCV_SIFIVE_CCACHE_ONLINE, &ccache_pmu->node);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to add CPU hotplug instance\n");
+
+	ret = perf_pmu_register(&ccache_pmu->pmu, "sifive_ccache_pmu", -1);
+	if (ret) {
+		dev_err_probe(dev, ret, "Failed to register PMU\n");
+		goto err_remove_instance;
+	}
+
+	return 0;
+
+err_remove_instance:
+	cpuhp_state_remove_instance(CPUHP_AP_PERF_RISCV_SIFIVE_CCACHE_ONLINE, &ccache_pmu->node);
+
+	return ret;
+}
+
+static void sifive_ccache_pmu_remove(struct platform_device *pdev)
+{
+	struct sifive_ccache_pmu *ccache_pmu = platform_get_drvdata(pdev);
+
+	perf_pmu_unregister(&ccache_pmu->pmu);
+	cpuhp_state_remove_instance(CPUHP_AP_PERF_RISCV_SIFIVE_CCACHE_ONLINE, &ccache_pmu->node);
+}
+
+static const struct of_device_id sifive_ccache_pmu_of_match[] = {
+	{ .compatible = "sifive,ccache0" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, sifive_ccache_pmu_of_match);
+
+static struct platform_driver sifive_ccache_pmu_driver = {
+	.probe	= sifive_ccache_pmu_probe,
+	.remove_new	= sifive_ccache_pmu_remove,
+	.driver	= {
+		.name		= "sifive_ccache_pmu",
+		.of_match_table	= sifive_ccache_pmu_of_match,
+	},
+};
+
+static void __exit sifive_ccache_pmu_exit(void)
+{
+	platform_driver_unregister(&sifive_ccache_pmu_driver);
+	cpuhp_remove_multi_state(CPUHP_AP_PERF_RISCV_SIFIVE_CCACHE_ONLINE);
+}
+module_exit(sifive_ccache_pmu_exit);
+
+static int __init sifive_ccache_pmu_init(void)
+{
+	int ret;
+
+	ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_RISCV_SIFIVE_CCACHE_ONLINE,
+				      "perf/sifive/ccache:online",
+				      sifive_ccache_pmu_online_cpu,
+				      sifive_ccache_pmu_offline_cpu);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&sifive_ccache_pmu_driver);
+	if (ret)
+		goto err_remove_state;
+
+	return 0;
+
+err_remove_state:
+	cpuhp_remove_multi_state(CPUHP_AP_PERF_RISCV_SIFIVE_CCACHE_ONLINE);
+
+	return ret;
+}
+module_init(sifive_ccache_pmu_init);
+
+MODULE_LICENSE("GPL");
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 172d0a743e5d..be6361fdc8ba 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -230,6 +230,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_POWERPC_TRACE_IMC_ONLINE,
 	CPUHP_AP_PERF_POWERPC_HV_24x7_ONLINE,
 	CPUHP_AP_PERF_POWERPC_HV_GPCI_ONLINE,
+	CPUHP_AP_PERF_RISCV_SIFIVE_CCACHE_ONLINE,
 	CPUHP_AP_PERF_CSKY_ONLINE,
 	CPUHP_AP_WATCHDOG_ONLINE,
 	CPUHP_AP_WORKQUEUE_ONLINE,
-- 
2.43.0

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