linux/drivers/perf/fujitsu_uncore_pmu.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for the Uncore PMUs in Fujitsu chips.
 *
 * See Documentation/admin-guide/perf/fujitsu_uncore_pmu.rst for more details.
 *
 * Copyright (c) 2025 Fujitsu. All rights reserved.
 */

#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>

/* Number of counters on each PMU */
#define MAC_NUM_COUNTERS  8
#define PCI_NUM_COUNTERS  8
/* Mask for the event type field within perf_event_attr.config and EVTYPE reg */
#define UNCORE_EVTYPE_MASK   0xFF

/* Perfmon registers */
#define PM_EVCNTR(__cntr)           (0x000 + (__cntr) * 8)
#define PM_CNTCTL(__cntr)           (0x100 + (__cntr) * 8)
#define PM_CNTCTL_RESET             0
#define PM_EVTYPE(__cntr)           (0x200 + (__cntr) * 8)
#define PM_EVTYPE_EVSEL(__val)      FIELD_GET(UNCORE_EVTYPE_MASK, __val)
#define PM_CR                       0x400
#define PM_CR_RESET                 BIT(1)
#define PM_CR_ENABLE                BIT(0)
#define PM_CNTENSET                 0x410
#define PM_CNTENSET_IDX(__cntr)     BIT(__cntr)
#define PM_CNTENCLR                 0x418
#define PM_CNTENCLR_IDX(__cntr)     BIT(__cntr)
#define PM_CNTENCLR_RESET           0xFF
#define PM_INTENSET                 0x420
#define PM_INTENSET_IDX(__cntr)     BIT(__cntr)
#define PM_INTENCLR                 0x428
#define PM_INTENCLR_IDX(__cntr)     BIT(__cntr)
#define PM_INTENCLR_RESET           0xFF
#define PM_OVSR                     0x440
#define PM_OVSR_OVSRCLR_RESET       0xFF

enum fujitsu_uncore_pmu {
	FUJITSU_UNCORE_PMU_MAC = 1,
	FUJITSU_UNCORE_PMU_PCI = 2,
};

struct uncore_pmu {
	int			num_counters;
	struct pmu		pmu;
	struct hlist_node	node;
	void __iomem		*regs;
	struct perf_event	**events;
	unsigned long		*used_mask;
	int			cpu;
	int			irq;
	struct device		*dev;
};

#define to_uncore_pmu(p) (container_of(p, struct uncore_pmu, pmu))

static int uncore_pmu_cpuhp_state;

static void fujitsu_uncore_counter_start(struct perf_event *event)
{
	struct uncore_pmu *uncorepmu = to_uncore_pmu(event->pmu);
	int idx = event->hw.idx;

	/* Initialize the hardware counter and reset prev_count*/
	local64_set(&event->hw.prev_count, 0);
	writeq_relaxed(0, uncorepmu->regs + PM_EVCNTR(idx));

	/* Set the event type */
	writeq_relaxed(PM_EVTYPE_EVSEL(event->attr.config), uncorepmu->regs + PM_EVTYPE(idx));

	/* Enable interrupt generation by this counter */
	writeq_relaxed(PM_INTENSET_IDX(idx), uncorepmu->regs + PM_INTENSET);

	/* Finally, enable the counter */
	writeq_relaxed(PM_CNTCTL_RESET, uncorepmu->regs + PM_CNTCTL(idx));
	writeq_relaxed(PM_CNTENSET_IDX(idx), uncorepmu->regs + PM_CNTENSET);
}

static void fujitsu_uncore_counter_stop(struct perf_event *event)
{
	struct uncore_pmu *uncorepmu = to_uncore_pmu(event->pmu);
	int idx = event->hw.idx;

	/* Disable the counter */
	writeq_relaxed(PM_CNTENCLR_IDX(idx), uncorepmu->regs + PM_CNTENCLR);

	/* Disable interrupt generation by this counter */
	writeq_relaxed(PM_INTENCLR_IDX(idx), uncorepmu->regs + PM_INTENCLR);
}

static void fujitsu_uncore_counter_update(struct perf_event *event)
{
	struct uncore_pmu *uncorepmu = to_uncore_pmu(event->pmu);
	int idx = event->hw.idx;
	u64 prev, new;

	do {
		prev = local64_read(&event->hw.prev_count);
		new = readq_relaxed(uncorepmu->regs + PM_EVCNTR(idx));
	} while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev);

	local64_add(new - prev, &event->count);
}

static inline void fujitsu_uncore_init(struct uncore_pmu *uncorepmu)
{
	int i;

	writeq_relaxed(PM_CR_RESET, uncorepmu->regs + PM_CR);

	writeq_relaxed(PM_CNTENCLR_RESET, uncorepmu->regs + PM_CNTENCLR);
	writeq_relaxed(PM_INTENCLR_RESET, uncorepmu->regs + PM_INTENCLR);
	writeq_relaxed(PM_OVSR_OVSRCLR_RESET, uncorepmu->regs + PM_OVSR);

	for (i = 0; i < uncorepmu->num_counters; ++i) {
		writeq_relaxed(PM_CNTCTL_RESET, uncorepmu->regs + PM_CNTCTL(i));
		writeq_relaxed(PM_EVTYPE_EVSEL(0), uncorepmu->regs + PM_EVTYPE(i));
	}
	writeq_relaxed(PM_CR_ENABLE, uncorepmu->regs + PM_CR);
}

static irqreturn_t fujitsu_uncore_handle_irq(int irq_num, void *data)
{
	struct uncore_pmu *uncorepmu = data;
	/* Read the overflow status register */
	long status = readq_relaxed(uncorepmu->regs + PM_OVSR);
	int idx;

	if (status == 0)
		return IRQ_NONE;

	/* Clear the bits we read on the overflow status register */
	writeq_relaxed(status, uncorepmu->regs + PM_OVSR);

	for_each_set_bit(idx, &status, uncorepmu->num_counters) {
		struct perf_event *event;

		event = uncorepmu->events[idx];
		if (!event)
			continue;

		fujitsu_uncore_counter_update(event);
	}

	return IRQ_HANDLED;
}

static void fujitsu_uncore_pmu_enable(struct pmu *pmu)
{
	writeq_relaxed(PM_CR_ENABLE, to_uncore_pmu(pmu)->regs + PM_CR);
}

static void fujitsu_uncore_pmu_disable(struct pmu *pmu)
{
	writeq_relaxed(0, to_uncore_pmu(pmu)->regs + PM_CR);
}

static bool fujitsu_uncore_validate_event_group(struct perf_event *event)
{
	struct uncore_pmu *uncorepmu = to_uncore_pmu(event->pmu);
	struct perf_event *leader = event->group_leader;
	struct perf_event *sibling;
	int counters = 1;

	if (leader == event)
		return true;

	if (leader->pmu == event->pmu)
		counters++;

	for_each_sibling_event(sibling, leader) {
		if (sibling->pmu == event->pmu)
			counters++;
	}

	/*
	 * If the group requires more counters than the HW has, it
	 * cannot ever be scheduled.
	 */
	return counters <= uncorepmu->num_counters;
}

static int fujitsu_uncore_event_init(struct perf_event *event)
{
	struct uncore_pmu *uncorepmu = to_uncore_pmu(event->pmu);
	struct hw_perf_event *hwc = &event->hw;

	/* Is the event for this PMU? */
	if (event->attr.type != event->pmu->type)
		return -ENOENT;

	/*
	 * Sampling not supported since these events are not
	 * core-attributable.
	 */
	if (is_sampling_event(event))
		return -EINVAL;

	/*
	 * Task mode not available, we run the counters as socket counters,
	 * not attributable to any CPU and therefore cannot attribute per-task.
	 */
	if (event->cpu < 0)
		return -EINVAL;

	/* Validate the group */
	if (!fujitsu_uncore_validate_event_group(event))
		return -EINVAL;

	hwc->idx = -1;

	event->cpu = uncorepmu->cpu;

	return 0;
}

static void fujitsu_uncore_event_start(struct perf_event *event, int flags)
{
	struct hw_perf_event *hwc = &event->hw;

	hwc->state = 0;
	fujitsu_uncore_counter_start(event);
}

static void fujitsu_uncore_event_stop(struct perf_event *event, int flags)
{
	struct hw_perf_event *hwc = &event->hw;

	if (hwc->state & PERF_HES_STOPPED)
		return;

	fujitsu_uncore_counter_stop(event);
	if (flags & PERF_EF_UPDATE)
		fujitsu_uncore_counter_update(event);
	hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
}

static int fujitsu_uncore_event_add(struct perf_event *event, int flags)
{
	struct uncore_pmu *uncorepmu = to_uncore_pmu(event->pmu);
	struct hw_perf_event *hwc = &event->hw;
	int idx;

	/* Try to allocate a counter. */
	idx = bitmap_find_free_region(uncorepmu->used_mask, uncorepmu->num_counters, 0);
	if (idx < 0)
		/* The counters are all in use. */
		return -EAGAIN;

	hwc->idx = idx;
	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
	uncorepmu->events[idx] = event;

	if (flags & PERF_EF_START)
		fujitsu_uncore_event_start(event, 0);

	/* Propagate changes to the userspace mapping. */
	perf_event_update_userpage(event);

	return 0;
}

static void fujitsu_uncore_event_del(struct perf_event *event, int flags)
{
	struct uncore_pmu *uncorepmu = to_uncore_pmu(event->pmu);
	struct hw_perf_event *hwc = &event->hw;

	/* Stop and clean up */
	fujitsu_uncore_event_stop(event, flags | PERF_EF_UPDATE);
	uncorepmu->events[hwc->idx] = NULL;
	bitmap_release_region(uncorepmu->used_mask, hwc->idx, 0);

	/* Propagate changes to the userspace mapping. */
	perf_event_update_userpage(event);
}

static void fujitsu_uncore_event_read(struct perf_event *event)
{
	fujitsu_uncore_counter_update(event);
}

#define UNCORE_PMU_FORMAT_ATTR(_name, _config)				      \
	(&((struct dev_ext_attribute[]) {				      \
		{ .attr = __ATTR(_name, 0444, device_show_string, NULL),      \
		  .var = (void *)_config, }				      \
	})[0].attr.attr)

static struct attribute *fujitsu_uncore_pmu_formats[] = {
	UNCORE_PMU_FORMAT_ATTR(event, "config:0-7"),
	NULL
};

static const struct attribute_group fujitsu_uncore_pmu_format_group = {
	.name = "format",
	.attrs = fujitsu_uncore_pmu_formats,
};

static ssize_t fujitsu_uncore_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 MAC_EVENT_ATTR(_name, _id)					     \
	PMU_EVENT_ATTR_ID(_name, fujitsu_uncore_pmu_event_show, _id)

static struct attribute *fujitsu_uncore_mac_pmu_events[] = {
	MAC_EVENT_ATTR(cycles,				0x00),
	MAC_EVENT_ATTR(read-count,			0x10),
	MAC_EVENT_ATTR(read-count-request,		0x11),
	MAC_EVENT_ATTR(read-count-return,		0x12),
	MAC_EVENT_ATTR(read-count-request-pftgt,	0x13),
	MAC_EVENT_ATTR(read-count-request-normal,	0x14),
	MAC_EVENT_ATTR(read-count-return-pftgt-hit,	0x15),
	MAC_EVENT_ATTR(read-count-return-pftgt-miss,	0x16),
	MAC_EVENT_ATTR(read-wait,			0x17),
	MAC_EVENT_ATTR(write-count,			0x20),
	MAC_EVENT_ATTR(write-count-write,		0x21),
	MAC_EVENT_ATTR(write-count-pwrite,		0x22),
	MAC_EVENT_ATTR(memory-read-count,		0x40),
	MAC_EVENT_ATTR(memory-write-count,		0x50),
	MAC_EVENT_ATTR(memory-pwrite-count,		0x60),
	MAC_EVENT_ATTR(ea-mac,				0x80),
	MAC_EVENT_ATTR(ea-memory,			0x90),
	MAC_EVENT_ATTR(ea-memory-mac-write,		0x92),
	MAC_EVENT_ATTR(ea-ha,				0xa0),
	NULL
};

#define PCI_EVENT_ATTR(_name, _id)					     \
	PMU_EVENT_ATTR_ID(_name, fujitsu_uncore_pmu_event_show, _id)

static struct attribute *fujitsu_uncore_pci_pmu_events[] = {
	PCI_EVENT_ATTR(pci-port0-cycles,		0x00),
	PCI_EVENT_ATTR(pci-port0-read-count,		0x10),
	PCI_EVENT_ATTR(pci-port0-read-count-bus,	0x14),
	PCI_EVENT_ATTR(pci-port0-write-count,		0x20),
	PCI_EVENT_ATTR(pci-port0-write-count-bus,	0x24),
	PCI_EVENT_ATTR(pci-port1-cycles,		0x40),
	PCI_EVENT_ATTR(pci-port1-read-count,		0x50),
	PCI_EVENT_ATTR(pci-port1-read-count-bus,	0x54),
	PCI_EVENT_ATTR(pci-port1-write-count,		0x60),
	PCI_EVENT_ATTR(pci-port1-write-count-bus,	0x64),
	PCI_EVENT_ATTR(ea-pci,				0x80),
	NULL
};

static const struct attribute_group fujitsu_uncore_mac_pmu_events_group = {
	.name = "events",
	.attrs = fujitsu_uncore_mac_pmu_events,
};

static const struct attribute_group fujitsu_uncore_pci_pmu_events_group = {
	.name = "events",
	.attrs = fujitsu_uncore_pci_pmu_events,
};

static ssize_t cpumask_show(struct device *dev,
			    struct device_attribute *attr, char *buf)
{
	struct uncore_pmu *uncorepmu = to_uncore_pmu(dev_get_drvdata(dev));

	return cpumap_print_to_pagebuf(true, buf, cpumask_of(uncorepmu->cpu));
}
static DEVICE_ATTR_RO(cpumask);

static struct attribute *fujitsu_uncore_pmu_cpumask_attrs[] = {
	&dev_attr_cpumask.attr,
	NULL
};

static const struct attribute_group fujitsu_uncore_pmu_cpumask_attr_group = {
	.attrs = fujitsu_uncore_pmu_cpumask_attrs,
};

static const struct attribute_group *fujitsu_uncore_mac_pmu_attr_grps[] = {
	&fujitsu_uncore_pmu_format_group,
	&fujitsu_uncore_mac_pmu_events_group,
	&fujitsu_uncore_pmu_cpumask_attr_group,
	NULL
};

static const struct attribute_group *fujitsu_uncore_pci_pmu_attr_grps[] = {
	&fujitsu_uncore_pmu_format_group,
	&fujitsu_uncore_pci_pmu_events_group,
	&fujitsu_uncore_pmu_cpumask_attr_group,
	NULL
};

static void fujitsu_uncore_pmu_migrate(struct uncore_pmu *uncorepmu, unsigned int cpu)
{
	perf_pmu_migrate_context(&uncorepmu->pmu, uncorepmu->cpu, cpu);
	irq_set_affinity(uncorepmu->irq, cpumask_of(cpu));
	uncorepmu->cpu = cpu;
}

static int fujitsu_uncore_pmu_online_cpu(unsigned int cpu, struct hlist_node *cpuhp_node)
{
	struct uncore_pmu *uncorepmu;
	int node;

	uncorepmu = hlist_entry_safe(cpuhp_node, struct uncore_pmu, node);
	node = dev_to_node(uncorepmu->dev);
	if (cpu_to_node(uncorepmu->cpu) != node && cpu_to_node(cpu) == node)
		fujitsu_uncore_pmu_migrate(uncorepmu, cpu);

	return 0;
}

static int fujitsu_uncore_pmu_offline_cpu(unsigned int cpu, struct hlist_node *cpuhp_node)
{
	struct uncore_pmu *uncorepmu;
	unsigned int target;
	int node;

	uncorepmu = hlist_entry_safe(cpuhp_node, struct uncore_pmu, node);
	if (cpu != uncorepmu->cpu)
		return 0;

	node = dev_to_node(uncorepmu->dev);
	target = cpumask_any_and_but(cpumask_of_node(node), cpu_online_mask, cpu);
	if (target >= nr_cpu_ids)
		target = cpumask_any_but(cpu_online_mask, cpu);

	if (target < nr_cpu_ids)
		fujitsu_uncore_pmu_migrate(uncorepmu, target);

	return 0;
}

static int fujitsu_uncore_pmu_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	unsigned long device_type = (unsigned long)device_get_match_data(dev);
	const struct attribute_group **attr_groups;
	struct uncore_pmu *uncorepmu;
	struct resource *memrc;
	size_t alloc_size;
	char *name;
	int ret;
	int irq;
	u64 uid;

	ret = acpi_dev_uid_to_integer(ACPI_COMPANION(dev), &uid);
	if (ret)
		return dev_err_probe(dev, ret, "unable to read ACPI uid\n");

	uncorepmu = devm_kzalloc(dev, sizeof(*uncorepmu), GFP_KERNEL);
	if (!uncorepmu)
		return -ENOMEM;
	uncorepmu->dev = dev;
	uncorepmu->cpu = cpumask_local_spread(0, dev_to_node(dev));
	platform_set_drvdata(pdev, uncorepmu);

	switch (device_type) {
	case FUJITSU_UNCORE_PMU_MAC:
		uncorepmu->num_counters = MAC_NUM_COUNTERS;
		attr_groups = fujitsu_uncore_mac_pmu_attr_grps;
		name = devm_kasprintf(dev, GFP_KERNEL, "mac_iod%llu_mac%llu_ch%llu",
				      (uid >> 8) & 0xF, (uid >> 4) & 0xF, uid & 0xF);
		break;
	case FUJITSU_UNCORE_PMU_PCI:
		uncorepmu->num_counters = PCI_NUM_COUNTERS;
		attr_groups = fujitsu_uncore_pci_pmu_attr_grps;
		name = devm_kasprintf(dev, GFP_KERNEL, "pci_iod%llu_pci%llu",
				      (uid >> 4) & 0xF, uid & 0xF);
		break;
	default:
		return dev_err_probe(dev, -EINVAL, "illegal device type: %lu\n", device_type);
	}
	if (!name)
		return -ENOMEM;

	uncorepmu->pmu = (struct pmu) {
		.parent		= dev,
		.task_ctx_nr	= perf_invalid_context,

		.attr_groups	= attr_groups,

		.pmu_enable	= fujitsu_uncore_pmu_enable,
		.pmu_disable	= fujitsu_uncore_pmu_disable,
		.event_init	= fujitsu_uncore_event_init,
		.add		= fujitsu_uncore_event_add,
		.del		= fujitsu_uncore_event_del,
		.start		= fujitsu_uncore_event_start,
		.stop		= fujitsu_uncore_event_stop,
		.read		= fujitsu_uncore_event_read,

		.capabilities	= PERF_PMU_CAP_NO_EXCLUDE | PERF_PMU_CAP_NO_INTERRUPT,
	};

	alloc_size = sizeof(uncorepmu->events[0]) * uncorepmu->num_counters;
	uncorepmu->events = devm_kzalloc(dev, alloc_size, GFP_KERNEL);
	if (!uncorepmu->events)
		return -ENOMEM;

	alloc_size = sizeof(uncorepmu->used_mask[0]) * BITS_TO_LONGS(uncorepmu->num_counters);
	uncorepmu->used_mask = devm_kzalloc(dev, alloc_size, GFP_KERNEL);
	if (!uncorepmu->used_mask)
		return -ENOMEM;

	uncorepmu->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &memrc);
	if (IS_ERR(uncorepmu->regs))
		return PTR_ERR(uncorepmu->regs);

	fujitsu_uncore_init(uncorepmu);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	ret = devm_request_irq(dev, irq, fujitsu_uncore_handle_irq,
			       IRQF_NOBALANCING | IRQF_NO_THREAD,
			       name, uncorepmu);
	if (ret)
		return dev_err_probe(dev, ret, "Failed to request IRQ:%d\n", irq);

	ret = irq_set_affinity(irq, cpumask_of(uncorepmu->cpu));
	if (ret)
		return dev_err_probe(dev, ret, "Failed to set irq affinity:%d\n", irq);

	uncorepmu->irq = irq;

	/* Add this instance to the list used by the offline callback */
	ret = cpuhp_state_add_instance(uncore_pmu_cpuhp_state, &uncorepmu->node);
	if (ret)
		return dev_err_probe(dev, ret, "Error registering hotplug");

	ret = perf_pmu_register(&uncorepmu->pmu, name, -1);
	if (ret < 0) {
		cpuhp_state_remove_instance_nocalls(uncore_pmu_cpuhp_state, &uncorepmu->node);
		return dev_err_probe(dev, ret, "Failed to register %s PMU\n", name);
	}

	dev_dbg(dev, "Registered %s, type: %d\n", name, uncorepmu->pmu.type);

	return 0;
}

static void fujitsu_uncore_pmu_remove(struct platform_device *pdev)
{
	struct uncore_pmu *uncorepmu = platform_get_drvdata(pdev);

	writeq_relaxed(0, uncorepmu->regs + PM_CR);

	perf_pmu_unregister(&uncorepmu->pmu);
	cpuhp_state_remove_instance_nocalls(uncore_pmu_cpuhp_state, &uncorepmu->node);
}

static const struct acpi_device_id fujitsu_uncore_pmu_acpi_match[] = {
	{ "FUJI200C", FUJITSU_UNCORE_PMU_MAC },
	{ "FUJI200D", FUJITSU_UNCORE_PMU_PCI },
	{ }
};
MODULE_DEVICE_TABLE(acpi, fujitsu_uncore_pmu_acpi_match);

static struct platform_driver fujitsu_uncore_pmu_driver = {
	.driver = {
		.name = "fujitsu-uncore-pmu",
		.acpi_match_table = fujitsu_uncore_pmu_acpi_match,
		.suppress_bind_attrs = true,
	},
	.probe = fujitsu_uncore_pmu_probe,
	.remove = fujitsu_uncore_pmu_remove,
};

static int __init fujitsu_uncore_pmu_init(void)
{
	int ret;

	/* Install a hook to update the reader CPU in case it goes offline */
	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
				      "perf/fujitsu/uncore:online",
				      fujitsu_uncore_pmu_online_cpu,
				      fujitsu_uncore_pmu_offline_cpu);
	if (ret < 0)
		return ret;

	uncore_pmu_cpuhp_state = ret;

	ret = platform_driver_register(&fujitsu_uncore_pmu_driver);
	if (ret)
		cpuhp_remove_multi_state(uncore_pmu_cpuhp_state);

	return ret;
}

static void __exit fujitsu_uncore_pmu_exit(void)
{
	platform_driver_unregister(&fujitsu_uncore_pmu_driver);
	cpuhp_remove_multi_state(uncore_pmu_cpuhp_state);
}

module_init(fujitsu_uncore_pmu_init);
module_exit(fujitsu_uncore_pmu_exit);

MODULE_AUTHOR("Koichi Okuno <fj2767dz@fujitsu.com>");
MODULE_DESCRIPTION("Fujitsu Uncore PMU driver");
MODULE_LICENSE("GPL");