[PATCH V5 2/4] drivers/perf: imx_ddr: Add ddr performance counter support

Frank Li
2019-04-16T20:39:57Z

Add ddr performance monitor support for iMX8QXP

There are 4 counters for ddr perfomance events.
counter 0 is dedicated for cycles.
you choose any up to 3 no cycles events.

for example:

perf stat -a -e ddr0/read-cycles/,ddr0/write-cycles/,ddr0/precharge/ ls
perf stat -a -e ddr0/cycles/,ddr0/read-access/,ddr0/write-access/ ls

Support below events.

ddr0/activate/ [Kernel PMU event]
ddr0/cycles/ [Kernel PMU event]
ddr0/hp-read-credit-cnt/ [Kernel PMU event]
ddr0/hp-read/ [Kernel PMU event]
ddr0/hp-req-nodcredit/ [Kernel PMU event]
ddr0/hp-xact-credit/ [Kernel PMU event]
ddr0/load-mode/ [Kernel PMU event]
ddr0/lp-read-credit-cnt/ [Kernel PMU event]
ddr0/lp-req-nocredit/ [Kernel PMU event]
ddr0/lp-xact-credit/ [Kernel PMU event]
ddr0/mwr/ [Kernel PMU event]
ddr0/precharge/ [Kernel PMU event]
ddr0/raw-hazard/ [Kernel PMU event]
ddr0/read-access/ [Kernel PMU event]
ddr0/read-activate/ [Kernel PMU event]
ddr0/read-command/ [Kernel PMU event]
ddr0/read-cycles/ [Kernel PMU event]
ddr0/read-modify-write-command/ [Kernel PMU event]
ddr0/read-queue-depth/ [Kernel PMU event]
ddr0/read-write-transition/ [Kernel PMU event]
ddr0/read/ [Kernel PMU event]
ddr0/refresh/ [Kernel PMU event]
ddr0/selfresh/ [Kernel PMU event]
ddr0/wr-xact-credit/ [Kernel PMU event]
ddr0/write-access/ [Kernel PMU event]
ddr0/write-command/ [Kernel PMU event]
ddr0/write-credit-cnt/ [Kernel PMU event]
ddr0/write-cycles/ [Kernel PMU event]
ddr0/write-queue-depth/ [Kernel PMU event]
ddr0/write/

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Change from v4 to v5
* Remove AXI ID filter function

Change from v3 to v4
* Change FSL_IMX8_DDR_PERF to FSL_IMX8_DDR_PMU
* sort include
* remove struct fsl_ddr_devtype_data
* Added comment need disable control first
* Added comment about must enable cycle counter
* Added macro for EVENT_AXI_READ, remove hardcode 0x41 and 0x42
* Added comment about cycle counter is fastest one

Change from v2 to v3
* remove kfree

Change from V1 to V2
* update Kconfig by use i.MX8 instead of i.MX8 QXP
* remove gpl statememnt since SPDX tag
* use dev_kzalloc
* use dev_err
* commit message show axi_read 0x41\axi_write 0x42
* commit message show cycles must be enabled
* Irq only issue at cycles overflow
* use NUM_COUNTER
* use devm_request_irq
* add hotplug callback to handle context migration

drivers/perf/Kconfig | 7 +
drivers/perf/Makefile | 1 +
drivers/perf/fsl_imx8_ddr_perf.c | 553 +++++++++++++++++++++++++++++++++++++++
3 files changed, 561 insertions(+)
create mode 100644 drivers/perf/fsl_imx8_ddr_perf.c

diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index a94e586..9bc3785 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -70,6 +70,13 @@ config ARM_DSU_PMU
system, control logic. The PMU allows counting various events related
to DSU.

+config FSL_IMX8_DDR_PMU
+ tristate "Freescale i.MX8 DDR perf monitor"
+ depends on ARCH_MXC
+ help
+ Provides support for ddr perfomance monitor in i.MX8. Provide memory
+ througput information.
+
config HISI_PMU
bool "HiSilicon SoC PMU"
depends on ARM64 && ACPI
diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
index 3048994..2ebb4de 100644
--- a/drivers/perf/Makefile
+++ b/drivers/perf/Makefile
@@ -5,6 +5,7 @@ obj-$(CONFIG_ARM_DSU_PMU) += arm_dsu_pmu.o
obj-$(CONFIG_ARM_PMU) += arm_pmu.o arm_pmu_platform.o
obj-$(CONFIG_ARM_PMU_ACPI) += arm_pmu_acpi.o
obj-$(CONFIG_ARM_SMMU_V3_PMU) += arm_smmuv3_pmu.o
+obj-$(CONFIG_FSL_IMX8_DDR_PMU) += fsl_imx8_ddr_perf.o
obj-$(CONFIG_HISI_PMU) += hisilicon/
obj-$(CONFIG_QCOM_L2_PMU) += qcom_l2_pmu.o
obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
diff --git a/drivers/perf/fsl_imx8_ddr_perf.c b/drivers/perf/fsl_imx8_ddr_perf.c
new file mode 100644
index 0000000..aed9414
--- /dev/null
+++ b/drivers/perf/fsl_imx8_ddr_perf.c
@@ -0,0 +1,553 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2017 NXP
+ * Copyright 2016 Freescale Semiconductor, Inc.
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/perf_event.h>
+#include <linux/slab.h>
+
+#define COUNTER_CNTL 0x0
+#define COUNTER_READ 0x20
+
+#define COUNTER_DPCR1 0x30
+
+#define CNTL_OVER 0x1
+#define CNTL_CLEAR 0x2
+#define CNTL_EN 0x4
+#define CNTL_EN_MASK 0xFFFFFFFB
+#define CNTL_CLEAR_MASK 0xFFFFFFFD
+#define CNTL_OVER_MASK 0xFFFFFFFE
+
+#define CNTL_CSV_SHIFT 24
+#define CNTL_CSV_MASK (0xFF << CNTL_CSV_SHIFT)
+
+#define EVENT_CYCLES_ID 0
+#define EVENT_CYCLES_COUNTER 0
+#define NUM_COUNTER 4
+#define MAX_EVENT 3
+#define EVENT_AXI_READ 0x41
+#define EVENT_AXI_WRITE 0x42
+
+#define to_ddr_pmu(p) container_of(p, struct ddr_pmu, pmu)
+
+#define DDR_PERF_DEV_NAME "ddr_perf"
+
+static DEFINE_IDA(ddr_ida);
+
+PMU_EVENT_ATTR_STRING(cycles, ddr_perf_cycles, "event=0x00");
+PMU_EVENT_ATTR_STRING(selfresh, ddr_perf_selfresh, "event=0x01");
+PMU_EVENT_ATTR_STRING(read-access, ddr_perf_read_accesses, "event=0x04");
+PMU_EVENT_ATTR_STRING(write-access, ddr_perf_write_accesses, "event=0x05");
+PMU_EVENT_ATTR_STRING(read-queue-depth, ddr_perf_read_queue_depth,
+ "event=0x08");
+PMU_EVENT_ATTR_STRING(write-queue-depth, ddr_perf_write_queue_depth,
+ "event=0x09");
+PMU_EVENT_ATTR_STRING(lp-read-credit-cnt, ddr_perf_lp_read_credit_cnt,
+ "event=0x10");
+PMU_EVENT_ATTR_STRING(hp-read-credit-cnt, ddr_perf_hp_read_credit_cnt,
+ "event=0x11");
+PMU_EVENT_ATTR_STRING(write-credit-cnt, ddr_perf_write_credit_cnt,
+ "event=0x12");
+PMU_EVENT_ATTR_STRING(read-command, ddr_perf_read_command, "event=0x20");
+PMU_EVENT_ATTR_STRING(write-command, ddr_perf_write_command, "event=0x21");
+PMU_EVENT_ATTR_STRING(read-modify-write-command,
+ ddr_perf_read_modify_write_command, "event=0x22");
+PMU_EVENT_ATTR_STRING(hp-read, ddr_perf_hp_read, "event=0x23");
+PMU_EVENT_ATTR_STRING(hp-req-nodcredit, ddr_perf_hp_req_nocredit, "event=0x24");
+PMU_EVENT_ATTR_STRING(hp-xact-credit, ddr_perf_hp_xact_credit, "event=0x25");
+PMU_EVENT_ATTR_STRING(lp-req-nocredit, ddr_perf_lp_req_nocredit, "event=0x26");
+PMU_EVENT_ATTR_STRING(lp-xact-credit, ddr_perf_lp_xact_credit, "event=0x27");
+PMU_EVENT_ATTR_STRING(wr-xact-credit, ddr_perf_wr_xact_credit, "event=0x29");
+PMU_EVENT_ATTR_STRING(read-cycles, ddr_perf_read_cycles, "event=0x2a");
+PMU_EVENT_ATTR_STRING(write-cycles, ddr_perf_write_cycles, "event=0x2b");
+PMU_EVENT_ATTR_STRING(read-write-transition, ddr_perf_read_write_transition,
+ "event=0x30");
+PMU_EVENT_ATTR_STRING(precharge, ddr_perf_precharge, "event=0x31");
+PMU_EVENT_ATTR_STRING(activate, ddr_perf_activate, "event=0x32");
+PMU_EVENT_ATTR_STRING(load-mode, ddr_perf_load_mode, "event=0x33");
+PMU_EVENT_ATTR_STRING(mwr, ddr_perf_mwr, "event=0x34");
+PMU_EVENT_ATTR_STRING(read, ddr_perf_read, "event=0x35");
+PMU_EVENT_ATTR_STRING(read-activate, ddr_perf_read_activate, "event=0x36");
+PMU_EVENT_ATTR_STRING(refresh, ddr_perf_refresh, "event=0x37");
+PMU_EVENT_ATTR_STRING(write, ddr_perf_write, "event=0x38");
+PMU_EVENT_ATTR_STRING(raw-hazard, ddr_perf_raw_hazard, "event=0x39");
+
+static const struct of_device_id imx_ddr_pmu_dt_ids[] = {
+ { .compatible = "fsl,imx8-ddr-pmu",},
+ { .compatible = "fsl,imx8m-ddr-pmu",},
+ { /* sentinel */ }
+};
+
+struct ddr_pmu {
+ struct pmu pmu;
+ void __iomem *base;
+ cpumask_t cpu;
+ struct hlist_node node;
+ struct device *dev;
+ struct perf_event *active_events[NUM_COUNTER];
+ int total_events;
+ enum cpuhp_state cpuhp_state;
+ bool cycles_active;
+ uintptr_t flags;
+};
+
+static ssize_t ddr_perf_cpumask_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct ddr_pmu *pmu = dev_get_drvdata(dev);
+
+ return cpumap_print_to_pagebuf(true, buf, &pmu->cpu);
+}
+
+static struct device_attribute ddr_perf_cpumask_attr =
+ __ATTR(cpumask, 0444, ddr_perf_cpumask_show, NULL);
+
+static struct attribute *ddr_perf_cpumask_attrs[] = {
+ &ddr_perf_cpumask_attr.attr,
+ NULL,
+};
+
+static struct attribute_group ddr_perf_cpumask_attr_group = {
+ .attrs = ddr_perf_cpumask_attrs,
+};
+
+static struct attribute *ddr_perf_events_attrs[] = {
+ &ddr_perf_cycles.attr.attr,
+ &ddr_perf_selfresh.attr.attr,
+ &ddr_perf_read_accesses.attr.attr,
+ &ddr_perf_write_accesses.attr.attr,
+ &ddr_perf_read_queue_depth.attr.attr,
+ &ddr_perf_write_queue_depth.attr.attr,
+ &ddr_perf_lp_read_credit_cnt.attr.attr,
+ &ddr_perf_hp_read_credit_cnt.attr.attr,
+ &ddr_perf_write_credit_cnt.attr.attr,
+ &ddr_perf_read_command.attr.attr,
+ &ddr_perf_write_command.attr.attr,
+ &ddr_perf_read_modify_write_command.attr.attr,
+ &ddr_perf_hp_read.attr.attr,
+ &ddr_perf_hp_req_nocredit.attr.attr,
+ &ddr_perf_hp_xact_credit.attr.attr,
+ &ddr_perf_lp_req_nocredit.attr.attr,
+ &ddr_perf_lp_xact_credit.attr.attr,
+ &ddr_perf_wr_xact_credit.attr.attr,
+ &ddr_perf_read_cycles.attr.attr,
+ &ddr_perf_write_cycles.attr.attr,
+ &ddr_perf_read_write_transition.attr.attr,
+ &ddr_perf_precharge.attr.attr,
+ &ddr_perf_activate.attr.attr,
+ &ddr_perf_load_mode.attr.attr,
+ &ddr_perf_mwr.attr.attr,
+ &ddr_perf_read.attr.attr,
+ &ddr_perf_read_activate.attr.attr,
+ &ddr_perf_refresh.attr.attr,
+ &ddr_perf_write.attr.attr,
+ &ddr_perf_raw_hazard.attr.attr,
+ NULL,
+};
+
+static struct attribute_group ddr_perf_events_attr_group = {
+ .name = "events",
+ .attrs = ddr_perf_events_attrs,
+};
+
+PMU_FORMAT_ATTR(event, "config:0-63");
+
+static struct attribute *ddr_perf_format_attrs[] = {
+ &format_attr_event.attr,
+ NULL,
+};
+
+static struct attribute_group ddr_perf_format_attr_group = {
+ .name = "format",
+ .attrs = ddr_perf_format_attrs,
+};
+
+static const struct attribute_group *attr_groups[] = {
+ &ddr_perf_events_attr_group,
+ &ddr_perf_format_attr_group,
+ &ddr_perf_cpumask_attr_group,
+ NULL,
+};
+
+static u32 ddr_perf_alloc_counter(struct ddr_pmu *pmu, int event)
+{
+ int i;
+
+ /* Always map cycle event to counter 0
+ Cycles counter is dedicated for cycle event
+ can't used for the other events
+ */
+ if (event == EVENT_CYCLES_ID)
+ return EVENT_CYCLES_COUNTER;
+
+ for (i = 1; i < NUM_COUNTER; i++)
+ if (pmu->active_events[i] == NULL)
+ return i;
+
+ return -ENOENT;
+}
+
+static u32 ddr_perf_free_counter(struct ddr_pmu *pmu, int counter)
+{
+ if (counter < 0 || counter >= NUM_COUNTER)
+ return -ENOENT;
+
+ pmu->active_events[counter] = NULL;
+
+ return 0;
+}
+
+static u32 ddr_perf_read_counter(struct ddr_pmu *pmu, int counter)
+{
+ return readl(pmu->base + COUNTER_READ + counter * 4);
+}
+
+static int ddr_perf_event_init(struct perf_event *event)
+{
+ struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+
+ if (event->attr.type != event->pmu->type)
+ return -ENOENT;
+
+ if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
+ return -EOPNOTSUPP;
+
+ if (event->cpu < 0) {
+ dev_warn(pmu->dev, "Can't provide per-task data!\n");
+ return -EOPNOTSUPP;
+ }
+
+ if (event->attr.exclude_user ||
+ event->attr.exclude_kernel ||
+ event->attr.exclude_hv ||
+ event->attr.exclude_idle ||
+ event->attr.exclude_host ||
+ event->attr.exclude_guest ||
+ event->attr.sample_period)
+ return -EINVAL;
+
+ event->cpu = cpumask_first(&pmu->cpu);
+ hwc->idx = -1;
+
+ return 0;
+}
+
+
+static void ddr_perf_event_update(struct perf_event *event)
+{
+ struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ u64 delta, prev_raw_count, new_raw_count;
+ int counter = hwc->idx;
+
+ do {
+ prev_raw_count = local64_read(&hwc->prev_count);
+ new_raw_count = ddr_perf_read_counter(pmu, counter);
+ } while (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
+ new_raw_count) != prev_raw_count);
+
+ delta = (new_raw_count - prev_raw_count) & 0xFFFFFFFF;
+
+ local64_add(delta, &event->count);
+}
+
+static void ddr_perf_event_enable(struct ddr_pmu *pmu, int config,
+ int counter, bool enable)
+{
+ u8 reg = counter * 4 + COUNTER_CNTL;
+ int val;
+
+ if (enable) {
+ /* must disable first, then enable again
+ * otherwise, cycle counter will not work
+ * if previous state is enabled.
+ */
+ writel(0, pmu->base + reg);
+ val = CNTL_EN | CNTL_CLEAR;
+ val |= (config << CNTL_CSV_SHIFT) & CNTL_CSV_MASK;
+ } else {
+ /* Disable counter */
+ val = readl(pmu->base + reg) & CNTL_EN_MASK;
+ }
+
+ writel(val, pmu->base + reg);
+
+ if (config == EVENT_CYCLES_ID)
+ pmu->cycles_active = enable;
+}
+
+static void ddr_perf_event_start(struct perf_event *event, int flags)
+{
+ struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ int counter = hwc->idx;
+
+ local64_set(&hwc->prev_count, 0);
+
+ ddr_perf_event_enable(pmu, event->attr.config, counter, true);
+ /*
+ * If the cycles counter wasn't explicitly selected,
+ * we will enable it now.
+ * cycles counter must be enabled otherwise other counters will
+ * stopped.
+ */
+ if (counter > 0 && !pmu->cycles_active)
+ ddr_perf_event_enable(pmu, EVENT_CYCLES_ID,
+ EVENT_CYCLES_COUNTER, true);
+}
+
+static int ddr_perf_event_add(struct perf_event *event, int flags)
+{
+ struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ int counter;
+ int cfg = event->attr.config;
+
+ counter = ddr_perf_alloc_counter(pmu, cfg);
+ if (counter < 0) {
+ dev_dbg(pmu->dev, "There are not enough counters\n");
+ return -EOPNOTSUPP;
+ }
+
+ pmu->active_events[counter] = event;
+ pmu->total_events++;
+ hwc->idx = counter;
+
+ if (flags & PERF_EF_START)
+ ddr_perf_event_start(event, flags);
+
+ local64_set(&hwc->prev_count, ddr_perf_read_counter(pmu, counter));
+
+ return 0;
+}
+
+static void ddr_perf_event_stop(struct perf_event *event, int flags)
+{
+ struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ int counter = hwc->idx;
+
+ ddr_perf_event_enable(pmu, event->attr.config, counter, false);
+ ddr_perf_event_update(event);
+}
+
+static void ddr_perf_event_del(struct perf_event *event, int flags)
+{
+ struct ddr_pmu *pmu = to_ddr_pmu(event->pmu);
+ struct hw_perf_event *hwc = &event->hw;
+ int counter = hwc->idx;
+
+ ddr_perf_event_stop(event, PERF_EF_UPDATE);
+
+ ddr_perf_free_counter(pmu, counter);
+ pmu->total_events--;
+ hwc->idx = -1;
+
+ /* If all events have stopped, stop the cycles counter as well */
+ if ((pmu->total_events == 0) && pmu->cycles_active)
+ ddr_perf_event_enable(pmu, EVENT_CYCLES_ID,
+ EVENT_CYCLES_COUNTER, false);
+}
+
+static int ddr_perf_init(struct ddr_pmu *pmu, void __iomem *base,
+ struct device *dev)
+{
+ *pmu = (struct ddr_pmu) {
+ .pmu = (struct pmu) {
+ .task_ctx_nr = perf_invalid_context,
+ .attr_groups = attr_groups,
+ .event_init = ddr_perf_event_init,
+ .add = ddr_perf_event_add,
+ .del = ddr_perf_event_del,
+ .start = ddr_perf_event_start,
+ .stop = ddr_perf_event_stop,
+ .read = ddr_perf_event_update,
+ },
+ .base = base,
+ .dev = dev,
+ };
+
+ return ida_simple_get(&ddr_ida, 0, 0, GFP_KERNEL);
+}
+
+static irqreturn_t ddr_perf_irq_handler(int irq, void *p)
+{
+ int i;
+ u8 reg;
+ int val;
+ int counter;
+ struct ddr_pmu *pmu = (struct ddr_pmu *) p;
+ struct perf_event *event;
+
+ /* Only cycles counter overflowed can issue irq. all counters will
+ * be stopped when cycles counter overflow. but other counter don't stop
+ * when overflow happen. Update all of the local counter values,
+ * then reset the cycles counter, so the others can continue
+ * counting. cycles counter is fastest counter in all events. at last
+ * 4 times than other counters.
+ */
+ for (i = 0; i < NUM_COUNTER; i++) {
+
+ if (!pmu->active_events[i])
+ continue;
+
+ event = pmu->active_events[i];
+ counter = event->hw.idx;
+ reg = counter * 4 + COUNTER_CNTL;
+ val = readl(pmu->base + reg);
+
+ ddr_perf_event_update(event);
+
+ if (counter == EVENT_CYCLES_COUNTER) {
+ ddr_perf_event_enable(pmu,
+ EVENT_CYCLES_ID,
+ EVENT_CYCLES_COUNTER,
+ true);
+ ddr_perf_event_update(event);
+ }
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int ddr_perf_offline_cpu(unsigned int cpu, struct hlist_node *node)
+{
+ struct ddr_pmu *pmu = hlist_entry_safe(node, struct ddr_pmu, node);
+ int target;
+
+ if (!cpumask_test_and_clear_cpu(cpu, &pmu->cpu))
+ return 0;
+
+ target = cpumask_any_but(cpu_online_mask, cpu);
+ if (target >= nr_cpu_ids)
+ return 0;
+
+ perf_pmu_migrate_context(&pmu->pmu, cpu, target);
+ cpumask_set_cpu(target, &pmu->cpu);
+
+ return 0;
+}
+
+static int ddr_perf_probe(struct platform_device *pdev)
+{
+ struct ddr_pmu *pmu;
+ struct device_node *np;
+ void __iomem *base;
+ struct resource *iomem;
+ char *name;
+ char *hpname;
+ int num;
+ int ret;
+ u32 irq;
+ const struct of_device_id *of_id =
+ of_match_device(imx_ddr_pmu_dt_ids, &pdev->dev);
+
+ iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ base = devm_ioremap_resource(&pdev->dev, iomem);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ np = pdev->dev.of_node;
+
+ pmu = devm_kzalloc(&pdev->dev, sizeof(*pmu), GFP_KERNEL);
+ if (!pmu)
+ return -ENOMEM;
+
+ num = ddr_perf_init(pmu, base, &pdev->dev);
+
+ name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "ddr%d", num);
+ if (!name)
+ return -ENOMEM;
+
+ hpname = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+ "perf/imx/ddr%d:online", num);
+ if (!hpname)
+ return -ENOMEM;
+
+ pmu->flags = (uintptr_t) of_id->data;
+
+ cpumask_set_cpu(raw_smp_processor_id(), &pmu->cpu);
+ ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, hpname, NULL,
+ ddr_perf_offline_cpu);
+
+ if (ret < 0) {
+ dev_err(&pdev->dev, "cpuhp_setup_state_multi failed\n");
+ goto ddr_perf_err;
+ }
+
+ pmu->cpuhp_state = ret;
+
+ /* Register the pmu instance for cpu hotplug */
+ cpuhp_state_add_instance_nocalls(pmu->cpuhp_state, &pmu->node);
+
+ ret = perf_pmu_register(&(pmu->pmu), name, -1);
+ if (ret)
+ goto ddr_perf_err;
+
+ /* Request irq */
+ irq = of_irq_get(np, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "Failed to get irq: %d", irq);
+ ret = irq;
+ goto ddr_perf_irq_err;
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq,
+ ddr_perf_irq_handler,
+ IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+ DDR_PERF_DEV_NAME,
+ pmu);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Request irq failed: %d", ret);
+ goto ddr_perf_irq_err;
+ }
+
+ return 0;
+
+ddr_perf_irq_err:
+ perf_pmu_unregister(&(pmu->pmu));
+
+ddr_perf_err:
+ if (pmu->cpuhp_state)
+ cpuhp_state_remove_instance_nocalls(pmu->cpuhp_state, &pmu->node);
+
+ dev_warn(&pdev->dev, "i.MX8 DDR Perf PMU failed (%d), disabled\n", ret);
+ return ret;
+}
+
+static int ddr_perf_remove(struct platform_device *pdev)
+{
+ struct ddr_pmu *pmu = platform_get_drvdata(pdev);
+
+ cpuhp_state_remove_instance_nocalls(pmu->cpuhp_state, &pmu->node);
+ perf_pmu_unregister(&pmu->pmu);
+
+ return 0;
+}
+
+static struct platform_driver imx_ddr_pmu_driver = {
+ .driver = {
+ .name = "imx-ddr-pmu",
+ .of_match_table = imx_ddr_pmu_dt_ids,
+ },
+ .probe = ddr_perf_probe,
+ .remove = ddr_perf_remove,
+};
+
+static int __init imx_ddr_pmu_init(void)
+{
+ return platform_driver_register(&imx_ddr_pmu_driver);
+}
+
+module_init(imx_ddr_pmu_init);