Re: [PATCH V12 2/4] drivers/perf: imx_ddr: Add ddr performance counter support

[Zhi Li <lznuaa@gmail.com>]

On Tue, May 7, 2019 at 2:30 PM Andrey Smirnov <andrew.smirnov@gmail.com> wrote:
>
> On Wed, May 1, 2019 at 11:43 AM Frank Li <frank.li@nxp.com> wrote:
> >
> > 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 imx8_ddr0/read-cycles/,imx8_ddr0/write-cycles/,imx8_ddr0/precharge/ ls
> > perf stat -a -e imx8_ddr0/cycles/,imx8_ddr0/read-access/,imx8_ddr0/write-access/ ls
> >
> > Support below events.
> >
> >   imx8_ddr0/activate/                                     [Kernel PMU event]
> >   imx8_ddr0/axid-read/                                    [Kernel PMU event]
> >   imx8_ddr0/axid-write/                                   [Kernel PMU event]
> >   imx8_ddr0/cycles/                                       [Kernel PMU event]
> >   imx8_ddr0/hp-read-credit-cnt/                           [Kernel PMU event]
> >   imx8_ddr0/hp-read/                                      [Kernel PMU event]
> >   imx8_ddr0/hp-req-nodcredit/                             [Kernel PMU event]
> >   imx8_ddr0/hp-xact-credit/                               [Kernel PMU event]
> >   imx8_ddr0/load-mode/                                    [Kernel PMU event]
> >   imx8_ddr0/lp-read-credit-cnt/                           [Kernel PMU event]
> >   imx8_ddr0/lp-req-nocredit/                              [Kernel PMU event]
> >   imx8_ddr0/lp-xact-credit/                               [Kernel PMU event]
> >   imx8_ddr0/mwr/                                          [Kernel PMU event]
> >   imx8_ddr0/precharge/                                    [Kernel PMU event]
> >   imx8_ddr0/raw-hazard/                                   [Kernel PMU event]
> >   imx8_ddr0/read-access/                                  [Kernel PMU event]
> >   imx8_ddr0/read-activate/                                [Kernel PMU event]
> >   imx8_ddr0/read-command/                                 [Kernel PMU event]
> >   imx8_ddr0/read-cycles/                                  [Kernel PMU event]
> >   imx8_ddr0/read-modify-write-command/                    [Kernel PMU event]
> >   imx8_ddr0/read-queue-depth/                             [Kernel PMU event]
> >   imx8_ddr0/read-write-transition/                        [Kernel PMU event]
> >   imx8_ddr0/read/                                         [Kernel PMU event]
> >   imx8_ddr0/refresh/                                      [Kernel PMU event]
> >   imx8_ddr0/selfresh/                                     [Kernel PMU event]
> >   imx8_ddr0/wr-xact-credit/                               [Kernel PMU event]
> >   imx8_ddr0/write-access/                                 [Kernel PMU event]
> >   imx8_ddr0/write-command/                                [Kernel PMU event]
> >   imx8_ddr0/write-credit-cnt/                             [Kernel PMU event]
> >   imx8_ddr0/write-cycles/                                 [Kernel PMU event]
> >   imx8_ddr0/write-queue-depth/                            [Kernel PMU event]
> >   imx8_ddr0/write/
> >
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
>
> Don't really have anything to suggest, that I already haven't. LGTM, so:
>
> Reviewed-by: Andrey Smirnov <andrew.smirnov@gmail.com>


Will Deacon:
            Is it okay to pick up these patches?  Andrey always acked.

best regards
Frank Li

>
>
> > ---
> >
> > Notes:
> >     Change from v11 to v12
> >     * change name from imx_ddr to imx8_ddr
> >
> >     Change from v10 to v11
> >      * using devm_platform_ioremap_resource
> >      * using help macro IMX8_DDR_PMU_EVENT_ATTR
> >
> >     Change from v9 to v10
> >      * use name imx8_ddr_perf_pmu
> >      * cpuhp_setup_state_multi use DDR_PERF_DEV_NAME
> >      * config: 0-7
> >      * use read_relaxed() at ddr_perf_read_counter
> >      * add .capabilities = PERF_PMU_CAP_NO_EXCLUDE
> >      * raname ddr_perf_event_start to ddr_perf_counter_enable
> >      * use FIELD_PREP
> >      * write 0 to disalbe counter at ddr_perf_event_enable
> >      * update hwc->state
> >      * remove local64_set at ddr_perf_event_add
> >      * move perf_pmu_register after irq_register to simplfy err handle
> >
> >     No change from v8 to v9
> >
> >     Change from v7 to v8
> >      * remove unused define
> >      * change total_events to active_events, change active_events to events
> >      * remove flags,
> >      * fix multi line comments code sytle
> >      * add pmu_enable\disable function
> >      * disable event at irq handle
> >      * remove counter check at ddr_perf_free_counter
> >      * remove pmu->irq check
> >      * add group check
> >
> >     Change from v6 to v7
> >      * added irq affinity handle, ref arm-ccn.c
> >      * added IRQF_NOBALANCING | IRQF_NO_THREAD
> >      * added ida_simple_remove at failure path
> >
> >     Change from v5 to v6
> >      * fix insmod\rmmod problem
> >      * remove randunt register read at irq handle
> >      * change u32 irq to int
> >      * devm_request_irq use default flags.
> >
> >     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 | 552 +++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 560 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..15b0772
> > --- /dev/null
> > +++ b/drivers/perf/fsl_imx8_ddr_perf.c
> > @@ -0,0 +1,552 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright 2017 NXP
> > + * Copyright 2016 Freescale Semiconductor, Inc.
> > + */
> > +
> > +#include <linux/bitfield.h>
> > +#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_COUNTERS           4
> > +
> > +#define to_ddr_pmu(p)          container_of(p, struct ddr_pmu, pmu)
> > +
> > +#define DDR_PERF_DEV_NAME      "imx8_ddr_perf_pmu"
> > +
> > +static DEFINE_IDA(ddr_ida);
> > +
> > +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;
> > +       unsigned int cpu;
> > +       struct  hlist_node node;
> > +       struct  device *dev;
> > +       struct perf_event *events[NUM_COUNTERS];
> > +       int active_events;
> > +       enum cpuhp_state cpuhp_state;
> > +       int irq;
> > +       int id;
> > +};
> > +
> > +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, cpumask_of(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 ssize_t
> > +ddr_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 sprintf(page, "event=0x%02llx\n", pmu_attr->id);
> > +}
> > +
> > +#define IMX8_DDR_PMU_EVENT_ATTR(_name, _id)                            \
> > +       (&((struct perf_pmu_events_attr[]) {                            \
> > +               { .attr = __ATTR(_name, 0444, ddr_pmu_event_show, NULL),\
> > +                 .id = _id, }                                          \
> > +       })[0].attr.attr)
> > +
> > +static struct attribute *ddr_perf_events_attrs[] = {
> > +       IMX8_DDR_PMU_EVENT_ATTR(cycles, EVENT_CYCLES_ID),
> > +       IMX8_DDR_PMU_EVENT_ATTR(selfresh, 0x01),
> > +       IMX8_DDR_PMU_EVENT_ATTR(read-accesses, 0x04),
> > +       IMX8_DDR_PMU_EVENT_ATTR(write-accesses, 0x05),
> > +       IMX8_DDR_PMU_EVENT_ATTR(read-queue-depth, 0x08),
> > +       IMX8_DDR_PMU_EVENT_ATTR(write-queue-depth, 0x09),
> > +       IMX8_DDR_PMU_EVENT_ATTR(lp-read-credit-cnt, 0x10),
> > +       IMX8_DDR_PMU_EVENT_ATTR(hp-read-credit-cnt, 0x11),
> > +       IMX8_DDR_PMU_EVENT_ATTR(write-credit-cnt, 0x12),
> > +       IMX8_DDR_PMU_EVENT_ATTR(read-command, 0x20),
> > +       IMX8_DDR_PMU_EVENT_ATTR(write-command, 0x21),
> > +       IMX8_DDR_PMU_EVENT_ATTR(read-modify-write-command, 0x22),
> > +       IMX8_DDR_PMU_EVENT_ATTR(hp-read, 0x23),
> > +       IMX8_DDR_PMU_EVENT_ATTR(hp-req-nocredit, 0x24),
> > +       IMX8_DDR_PMU_EVENT_ATTR(hp-xact-credit, 0x25),
> > +       IMX8_DDR_PMU_EVENT_ATTR(lp-req-nocredit, 0x26),
> > +       IMX8_DDR_PMU_EVENT_ATTR(lp-xact-credit, 0x27),
> > +       IMX8_DDR_PMU_EVENT_ATTR(wr-xact-credit, 0x29),
> > +       IMX8_DDR_PMU_EVENT_ATTR(read-cycles, 0x2a),
> > +       IMX8_DDR_PMU_EVENT_ATTR(write-cycles, 0x2b),
> > +       IMX8_DDR_PMU_EVENT_ATTR(read-write-transition, 0x30),
> > +       IMX8_DDR_PMU_EVENT_ATTR(precharge, 0x31),
> > +       IMX8_DDR_PMU_EVENT_ATTR(activate, 0x32),
> > +       IMX8_DDR_PMU_EVENT_ATTR(load-mode, 0x33),
> > +       IMX8_DDR_PMU_EVENT_ATTR(perf-mwr, 0x34),
> > +       IMX8_DDR_PMU_EVENT_ATTR(read, 0x35),
> > +       IMX8_DDR_PMU_EVENT_ATTR(read-activate, 0x36),
> > +       IMX8_DDR_PMU_EVENT_ATTR(refresh, 0x37),
> > +       IMX8_DDR_PMU_EVENT_ATTR(write, 0x38),
> > +       IMX8_DDR_PMU_EVENT_ATTR(raw-hazard, 0x39),
> > +       NULL,
> > +};
> > +
> > +static struct attribute_group ddr_perf_events_attr_group = {
> > +       .name = "events",
> > +       .attrs = ddr_perf_events_attrs,
> > +};
> > +
> > +PMU_FORMAT_ATTR(event, "config:0-7");
> > +
> > +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) {
> > +               if (pmu->events[EVENT_CYCLES_COUNTER] == NULL)
> > +                       return EVENT_CYCLES_COUNTER;
> > +               else
> > +                       return -ENOENT;
> > +       }
> > +
> > +       for (i = 1; i < NUM_COUNTERS; i++) {
> > +               if (pmu->events[i] == NULL)
> > +                       return i;
> > +       }
> > +
> > +       return -ENOENT;
> > +}
> > +
> > +static void ddr_perf_free_counter(struct ddr_pmu *pmu, int counter)
> > +{
> > +       pmu->events[counter] = NULL;
> > +}
> > +
> > +static u32 ddr_perf_read_counter(struct ddr_pmu *pmu, int counter)
> > +{
> > +       return readl_relaxed(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;
> > +       struct perf_event *sibling;
> > +
> > +       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;
> > +       }
> > +
> > +       /*
> > +        * We must NOT create groups containing mixed PMUs, although software
> > +        * events are acceptable (for example to create a CCN group
> > +        * periodically read when a hrtimer aka cpu-clock leader triggers).
> > +        */
> > +       if (event->group_leader->pmu != event->pmu &&
> > +                       !is_software_event(event->group_leader))
> > +               return -EINVAL;
> > +
> > +       for_each_sibling_event(sibling, event->group_leader) {
> > +               if (sibling->pmu != event->pmu &&
> > +                               !is_software_event(sibling))
> > +                       return -EINVAL;
> > +       }
> > +
> > +       event->cpu = 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_counter_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 |= FIELD_PREP(CNTL_CSV_MASK, config);
> > +               writel(val, pmu->base + reg);
> > +       } else {
> > +               /* Disable counter */
> > +               writel(0, pmu->base + reg);
> > +       }
> > +}
> > +
> > +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_counter_enable(pmu, event->attr.config, counter, true);
> > +
> > +       hwc->state = 0;
> > +}
> > +
> > +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->events[counter] = event;
> > +       pmu->active_events++;
> > +       hwc->idx = counter;
> > +
> > +       hwc->state |= PERF_HES_STOPPED;
> > +
> > +       if (flags & PERF_EF_START)
> > +               ddr_perf_event_start(event, flags);
> > +
> > +       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_counter_enable(pmu, event->attr.config, counter, false);
> > +       ddr_perf_event_update(event);
> > +
> > +       hwc->state |= PERF_HES_STOPPED;
> > +}
> > +
> > +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->active_events--;
> > +       hwc->idx = -1;
> > +}
> > +
> > +static void ddr_perf_pmu_enable(struct pmu *pmu)
> > +{
> > +       struct ddr_pmu *ddr_pmu = to_ddr_pmu(pmu);
> > +
> > +       /* enable cycle counter if cycle is not active event list */
> > +       if (ddr_pmu->events[EVENT_CYCLES_COUNTER] == NULL)
> > +               ddr_perf_counter_enable(ddr_pmu,
> > +                                     EVENT_CYCLES_ID,
> > +                                     EVENT_CYCLES_COUNTER,
> > +                                     true);
> > +}
> > +
> > +static void ddr_perf_pmu_disable(struct pmu *pmu)
> > +{
> > +       struct ddr_pmu *ddr_pmu = to_ddr_pmu(pmu);
> > +
> > +       if (ddr_pmu->events[EVENT_CYCLES_COUNTER] == NULL)
> > +               ddr_perf_counter_enable(ddr_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) {
> > +                       .capabilities = PERF_PMU_CAP_NO_EXCLUDE,
> > +                       .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,
> > +                       .pmu_enable  = ddr_perf_pmu_enable,
> > +                       .pmu_disable = ddr_perf_pmu_disable,
> > +               },
> > +               .base = base,
> > +               .dev = dev,
> > +       };
> > +
> > +       pmu->id = ida_simple_get(&ddr_ida, 0, 0, GFP_KERNEL);
> > +       return pmu->id;
> > +}
> > +
> > +static irqreturn_t ddr_perf_irq_handler(int irq, void *p)
> > +{
> > +       int i;
> > +       struct ddr_pmu *pmu = (struct ddr_pmu *) p;
> > +       struct perf_event *event, *cycle_event = NULL;
> > +
> > +       /* all counter will stop if cycle counter disabled */
> > +       ddr_perf_counter_enable(pmu,
> > +                             EVENT_CYCLES_ID,
> > +                             EVENT_CYCLES_COUNTER,
> > +                             false);
> > +       /*
> > +        * When the cycle counter overflows, all counters are stopped,
> > +        * and an IRQ is raised. If any other counter overflows, it
> > +        * continues counting, and no IRQ is raised.
> > +        *
> > +        * Cycles occur at least 4 times as often as other events, so we
> > +        * can update all events on a cycle counter overflow and not
> > +        * lose events.
> > +        *
> > +        */
> > +       for (i = 0; i < NUM_COUNTERS; i++) {
> > +
> > +               if (!pmu->events[i])
> > +                       continue;
> > +
> > +               event = pmu->events[i];
> > +
> > +               ddr_perf_event_update(event);
> > +
> > +               if (event->hw.idx == EVENT_CYCLES_COUNTER)
> > +                       cycle_event = event;
> > +       }
> > +
> > +       ddr_perf_counter_enable(pmu,
> > +                             EVENT_CYCLES_ID,
> > +                             EVENT_CYCLES_COUNTER,
> > +                             true);
> > +       if (cycle_event)
> > +               ddr_perf_event_update(cycle_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 (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);
> > +       pmu->cpu = target;
> > +
> > +       WARN_ON(irq_set_affinity_hint(pmu->irq, cpumask_of(pmu->cpu)));
> > +
> > +       return 0;
> > +}
> > +
> > +static int ddr_perf_probe(struct platform_device *pdev)
> > +{
> > +       struct ddr_pmu *pmu;
> > +       struct device_node *np;
> > +       void __iomem *base;
> > +       char *name;
> > +       int num;
> > +       int ret;
> > +       int irq;
> > +
> > +       base = devm_platform_ioremap_resource(pdev, 0);
> > +       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);
> > +
> > +       platform_set_drvdata(pdev, pmu);
> > +
> > +       name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "imx8_ddr%d", num);
> > +       if (!name)
> > +               return -ENOMEM;
> > +
> > +       pmu->cpu = raw_smp_processor_id();
> > +       ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
> > +                                     DDR_PERF_DEV_NAME,
> > +                                     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);
> > +
> > +       /* 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_err;
> > +       }
> > +
> > +       ret = devm_request_irq(&pdev->dev, irq,
> > +                                       ddr_perf_irq_handler,
> > +                                       IRQF_NOBALANCING | IRQF_NO_THREAD,
> > +                                       DDR_PERF_DEV_NAME,
> > +                                       pmu);
> > +       if (ret < 0) {
> > +               dev_err(&pdev->dev, "Request irq failed: %d", ret);
> > +               goto ddr_perf_err;
> > +       }
> > +
> > +       pmu->irq = irq;
> > +       ret = irq_set_affinity_hint(pmu->irq, cpumask_of(pmu->cpu));
> > +       if (ret) {
> > +               dev_err(pmu->dev, "Failed to set interrupt affinity!\n");
> > +               goto ddr_perf_err;
> > +       }
> > +
> > +       ret = perf_pmu_register(&pmu->pmu, name, -1);
> > +       if (ret)
> > +               goto ddr_perf_err;
> > +
> > +       return 0;
> > +
> > +ddr_perf_err:
> > +       if (pmu->cpuhp_state)
> > +               cpuhp_state_remove_instance_nocalls(pmu->cpuhp_state, &pmu->node);
> > +
> > +       ida_simple_remove(&ddr_ida, pmu->id);
> > +       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);
> > +       irq_set_affinity_hint(pmu->irq, NULL);
> > +
> > +       perf_pmu_unregister(&pmu->pmu);
> > +
> > +       ida_simple_remove(&ddr_ida, pmu->id);
> > +       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,
> > +};
> > +
> > +module_platform_driver(imx_ddr_pmu_driver);
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.5.2
> >

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