[PATCH v4 1/2] perf: arm_cspmu: Add support for ARM CoreSight PMU driver

Besar Wicaksono bwicaksono at nvidia.com
Tue Sep 27 18:27:04 PDT 2022



> -----Original Message-----
> From: Suzuki K Poulose <suzuki.poulose at arm.com>
> Sent: Tuesday, September 27, 2022 6:39 AM
> To: Besar Wicaksono <bwicaksono at nvidia.com>; robin.murphy at arm.com;
> catalin.marinas at arm.com; will at kernel.org; mark.rutland at arm.com
> Cc: linux-arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org;
> linux-tegra at vger.kernel.org; sudeep.holla at arm.com;
> thanu.rangarajan at arm.com; Michael.Williams at arm.com; Thierry Reding
> <treding at nvidia.com>; Jonathan Hunter <jonathanh at nvidia.com>; Vikram
> Sethi <vsethi at nvidia.com>; mathieu.poirier at linaro.org;
> mike.leach at linaro.org; leo.yan at linaro.org
> Subject: Re: [PATCH v4 1/2] perf: arm_cspmu: Add support for ARM
> CoreSight PMU driver
> 
> External email: Use caution opening links or attachments
> 
> 
> On 14/08/2022 19:23, Besar Wicaksono wrote:
> > Add support for ARM CoreSight PMU driver framework and interfaces.
> > The driver provides generic implementation to operate uncore PMU based
> > on ARM CoreSight PMU architecture. The driver also provides interface
> > to get vendor/implementation specific information, for example event
> > attributes and formating.
> >
> > The specification used in this implementation can be found below:
> >   * ACPI Arm Performance Monitoring Unit table:
> >          https://developer.arm.com/documentation/den0117/latest
> >   * ARM Coresight PMU architecture:
> >          https://developer.arm.com/documentation/ihi0091/latest
> >
> > Signed-off-by: Besar Wicaksono <bwicaksono at nvidia.com>
> > ---
> >   arch/arm64/configs/defconfig       |    1 +
> >   drivers/perf/Kconfig               |    2 +
> >   drivers/perf/Makefile              |    1 +
> >   drivers/perf/arm_cspmu/Kconfig     |   13 +
> >   drivers/perf/arm_cspmu/Makefile    |    6 +
> >   drivers/perf/arm_cspmu/arm_cspmu.c | 1262
> ++++++++++++++++++++++++++++
> >   drivers/perf/arm_cspmu/arm_cspmu.h |  151 ++++
> >   7 files changed, 1436 insertions(+)
> >   create mode 100644 drivers/perf/arm_cspmu/Kconfig
> >   create mode 100644 drivers/perf/arm_cspmu/Makefile
> >   create mode 100644 drivers/perf/arm_cspmu/arm_cspmu.c
> >   create mode 100644 drivers/perf/arm_cspmu/arm_cspmu.h
> >
> > diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
> > index 7d1105343bc2..ee31c9159a5b 100644
> > --- a/arch/arm64/configs/defconfig
> > +++ b/arch/arm64/configs/defconfig
> > @@ -1212,6 +1212,7 @@ CONFIG_PHY_UNIPHIER_USB3=y
> >   CONFIG_PHY_TEGRA_XUSB=y
> >   CONFIG_PHY_AM654_SERDES=m
> >   CONFIG_PHY_J721E_WIZ=m
> > +CONFIG_ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU=y
> >   CONFIG_ARM_SMMU_V3_PMU=m
> >   CONFIG_FSL_IMX8_DDR_PMU=m
> >   CONFIG_QCOM_L2_PMU=y
> > diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
> > index 1e2d69453771..c94d3601eb48 100644
> > --- a/drivers/perf/Kconfig
> > +++ b/drivers/perf/Kconfig
> > @@ -192,4 +192,6 @@ config MARVELL_CN10K_DDR_PMU
> >         Enable perf support for Marvell DDR Performance monitoring
> >         event on CN10K platform.
> >
> > +source "drivers/perf/arm_cspmu/Kconfig"
> > +
> >   endmenu
> > diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
> > index 57a279c61df5..3bc9323f0965 100644
> > --- a/drivers/perf/Makefile
> > +++ b/drivers/perf/Makefile
> > @@ -20,3 +20,4 @@ obj-$(CONFIG_ARM_DMC620_PMU) +=
> arm_dmc620_pmu.o
> >   obj-$(CONFIG_MARVELL_CN10K_TAD_PMU) +=
> marvell_cn10k_tad_pmu.o
> >   obj-$(CONFIG_MARVELL_CN10K_DDR_PMU) +=
> marvell_cn10k_ddr_pmu.o
> >   obj-$(CONFIG_APPLE_M1_CPU_PMU) += apple_m1_cpu_pmu.o
> > +obj-$(CONFIG_ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU) +=
> arm_cspmu/
> > diff --git a/drivers/perf/arm_cspmu/Kconfig
> b/drivers/perf/arm_cspmu/Kconfig
> > new file mode 100644
> > index 000000000000..c2c56ecafccb
> > --- /dev/null
> > +++ b/drivers/perf/arm_cspmu/Kconfig
> > @@ -0,0 +1,13 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +#
> > +# Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES.
> > +
> > +config ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU
> > +     tristate "ARM Coresight Architecture PMU"
> > +     depends on ACPI
> > +     depends on ACPI_APMT || COMPILE_TEST
> > +     help
> > +       Provides support for performance monitoring unit (PMU) devices
> > +       based on ARM CoreSight PMU architecture. Note that this PMU
> > +       architecture does not have relationship with the ARM CoreSight
> > +       Self-Hosted Tracing.
> > diff --git a/drivers/perf/arm_cspmu/Makefile
> b/drivers/perf/arm_cspmu/Makefile
> > new file mode 100644
> > index 000000000000..cdc3455f74d8
> > --- /dev/null
> > +++ b/drivers/perf/arm_cspmu/Makefile
> > @@ -0,0 +1,6 @@
> > +# Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES.
> > +#
> > +# SPDX-License-Identifier: GPL-2.0
> > +
> > +obj-$(CONFIG_ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU) += \
> > +     arm_cspmu.o
> > diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c
> b/drivers/perf/arm_cspmu/arm_cspmu.c
> > new file mode 100644
> > index 000000000000..410876f86eb0
> > --- /dev/null
> > +++ b/drivers/perf/arm_cspmu/arm_cspmu.c
> > @@ -0,0 +1,1262 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * ARM CoreSight Architecture PMU driver.
> > + *
> > + * This driver adds support for uncore PMU based on ARM CoreSight
> Performance
> > + * Monitoring Unit Architecture. The PMU is accessible via MMIO registers
> and
> > + * like other uncore PMUs, it does not support process specific events and
> > + * cannot be used in sampling mode.
> > + *
> > + * This code is based on other uncore PMUs like ARM DSU PMU. It
> provides a
> > + * generic implementation to operate the PMU according to CoreSight
> PMU
> > + * architecture and ACPI ARM PMU table (APMT) documents below:
> > + *   - ARM CoreSight PMU architecture document number: ARM IHI 0091
> A.a-00bet0.
> > + *   - APMT document number: ARM DEN0117.
> > + *
> > + * The user should refer to the vendor technical documentation to get
> details
> > + * about the supported events.
> > + *
> > + * Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES.
> > + *
> > + */
> > +
> > +#include <linux/acpi.h>
> > +#include <linux/cacheinfo.h>
> > +#include <linux/ctype.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io-64-nonatomic-lo-hi.h>
> > +#include <linux/module.h>
> > +#include <linux/perf_event.h>
> > +#include <linux/platform_device.h>
> > +#include <acpi/processor.h>
> > +
> > +#include "arm_cspmu.h"
> > +
> > +#define PMUNAME "arm_cspmu"
> > +#define DRVNAME "arm-cs-arch-pmu"
> > +
> > +#define ARM_CSPMU_CPUMASK_ATTR(_name, _config)                       \
> > +     ARM_CSPMU_EXT_ATTR(_name, arm_cspmu_cpumask_show,       \
> > +                             (unsigned long)_config)
> > +
> > +/*
> > + * CoreSight PMU Arch register offsets.
> > + */
> > +#define PMEVCNTR_LO                                  0x0
> > +#define PMEVCNTR_HI                                  0x4
> > +#define PMEVTYPER                                    0x400
> > +#define PMCCFILTR                                    0x47C
> > +#define PMEVFILTR                                    0xA00
> > +#define PMCNTENSET                                   0xC00
> > +#define PMCNTENCLR                                   0xC20
> > +#define PMINTENSET                                   0xC40
> > +#define PMINTENCLR                                   0xC60
> > +#define PMOVSCLR                                     0xC80
> > +#define PMOVSSET                                     0xCC0
> > +#define PMCFGR                                               0xE00
> > +#define PMCR                                         0xE04
> > +#define PMIIDR                                               0xE08
> > +
> > +/* PMCFGR register field */
> > +#define PMCFGR_NCG                                   GENMASK(31, 28)
> > +#define PMCFGR_HDBG                                  BIT(24)
> > +#define PMCFGR_TRO                                   BIT(23)
> > +#define PMCFGR_SS                                    BIT(22)
> > +#define PMCFGR_FZO                                   BIT(21)
> > +#define PMCFGR_MSI                                   BIT(20)
> > +#define PMCFGR_UEN                                   BIT(19)
> > +#define PMCFGR_NA                                    BIT(17)
> > +#define PMCFGR_EX                                    BIT(16)
> > +#define PMCFGR_CCD                                   BIT(15)
> > +#define PMCFGR_CC                                    BIT(14)
> > +#define PMCFGR_SIZE                                  GENMASK(13, 8)
> > +#define PMCFGR_N                                     GENMASK(7, 0)
> > +
> > +/* PMCR register field */
> > +#define PMCR_TRO                                     BIT(11)
> > +#define PMCR_HDBG                                    BIT(10)
> > +#define PMCR_FZO                                     BIT(9)
> > +#define PMCR_NA                                              BIT(8)
> > +#define PMCR_DP                                              BIT(5)
> > +#define PMCR_X                                               BIT(4)
> > +#define PMCR_D                                               BIT(3)
> > +#define PMCR_C                                               BIT(2)
> > +#define PMCR_P                                               BIT(1)
> > +#define PMCR_E                                               BIT(0)
> > +
> > +/* Each SET/CLR register supports up to 32 counters. */
> > +#define ARM_CSPMU_SET_CLR_COUNTER_SHIFT              5
> > +#define ARM_CSPMU_SET_CLR_COUNTER_NUM                \
> > +     (1 << ARM_CSPMU_SET_CLR_COUNTER_SHIFT)
> > +
> > +/* The number of 32-bit SET/CLR register that can be supported. */
> > +#define ARM_CSPMU_SET_CLR_MAX_NUM ((PMCNTENCLR -
> PMCNTENSET) / sizeof(u32))
> > +
> > +static_assert(
> > +     (ARM_CSPMU_SET_CLR_MAX_NUM *
> ARM_CSPMU_SET_CLR_COUNTER_NUM) >=
> > +     ARM_CSPMU_MAX_HW_CNTRS);
> > +
> > +/* Convert counter idx into SET/CLR register number. */
> > +#define COUNTER_TO_SET_CLR_ID(idx)                   \
> > +     (idx >> ARM_CSPMU_SET_CLR_COUNTER_SHIFT)
> > +
> > +/* Convert counter idx into SET/CLR register bit. */
> > +#define COUNTER_TO_SET_CLR_BIT(idx)                  \
> > +     (idx & (ARM_CSPMU_SET_CLR_COUNTER_NUM - 1))
> > +
> > +#define ARM_CSPMU_ACTIVE_CPU_MASK            0x0
> > +#define ARM_CSPMU_ASSOCIATED_CPU_MASK                0x1
> > +
> > +/* Check if field f in flags is set with value v */
> > +#define CHECK_APMT_FLAG(flags, f, v) \
> > +     ((flags & (ACPI_APMT_FLAGS_ ## f)) == (ACPI_APMT_FLAGS_ ## f ##
> _ ## v))
> > +
> > +/* Check and use default if implementer doesn't provide attribute
> callback */
> > +#define CHECK_DEFAULT_IMPL_OPS(ops, callback)                        \
> > +     do {                                                    \
> > +             if (!ops->callback)                             \
> > +                     ops->callback = arm_cspmu_ ## callback; \
> > +     } while (0)
> > +
> > +static unsigned long arm_cspmu_cpuhp_state;
> > +
> > +/*
> > + * In CoreSight PMU architecture, all of the MMIO registers are 32-bit
> except
> > + * counter register. The counter register can be implemented as 32-bit or
> 64-bit
> > + * register depending on the value of PMCFGR.SIZE field. For 64-bit
> access,
> > + * single-copy 64-bit atomic support is implementation defined. APMT
> node flag
> > + * is used to identify if the PMU supports 64-bit single copy atomic. If 64-
> bit
> > + * single copy atomic is not supported, the driver treats the register as a
> pair
> > + * of 32-bit register.
> > + */
> > +
> > +/*
> > + * Read 64-bit register as a pair of 32-bit registers using hi-lo-hi sequence.
> > + */
> > +static u64 read_reg64_hilohi(const void __iomem *addr)
> > +{
> > +     u32 val_lo, val_hi;
> > +     u64 val;
> > +
> > +     /* Use high-low-high sequence to avoid tearing */
> > +     do {
> > +             val_hi = readl(addr + 4);
> > +             val_lo = readl(addr);
> > +     } while (val_hi != readl(addr + 4));
> > +
> > +     val = (((u64)val_hi << 32) | val_lo);
> > +
> > +     return val;
> > +}
> > +
> > +/* Check if PMU supports 64-bit single copy atomic. */
> > +static inline bool supports_64bit_atomics(const struct arm_cspmu
> *cspmu)
> > +{
> > +     return CHECK_APMT_FLAG(cspmu->apmt_node->flags, ATOMIC,
> SUPP);
> > +}
> > +
> > +/* Check if cycle counter is supported. */
> > +static inline bool supports_cycle_counter(const struct arm_cspmu
> *cspmu)
> > +{
> > +     return (cspmu->pmcfgr & PMCFGR_CC);
> > +}
> > +
> > +/* Get counter size, which is (PMCFGR_SIZE + 1). */
> > +static inline u32 counter_size(const struct arm_cspmu *cspmu)
> > +{
> > +     return FIELD_GET(PMCFGR_SIZE, cspmu->pmcfgr) + 1;
> > +}
> > +
> > +/* Get counter mask. */
> > +static inline u64 counter_mask(const struct arm_cspmu *cspmu)
> > +{
> > +     return GENMASK_ULL(counter_size(cspmu) - 1, 0);
> > +}
> > +
> > +/* Check if counter is implemented as 64-bit register. */
> > +static inline bool use_64b_counter_reg(const struct arm_cspmu *cspmu)
> > +{
> > +     return (counter_size(cspmu) > 32);
> > +}
> > +
> > +ssize_t arm_cspmu_sysfs_event_show(struct device *dev,
> > +                             struct device_attribute *attr, char *buf)
> > +{
> > +     struct dev_ext_attribute *eattr =
> > +             container_of(attr, struct dev_ext_attribute, attr);
> > +     return sysfs_emit(buf, "event=0x%llx\n",
> > +                       (unsigned long long)eattr->var);
> > +}
> > +EXPORT_SYMBOL_GPL(arm_cspmu_sysfs_event_show);
> > +
> > +/* Default event list. */
> > +static struct attribute *arm_cspmu_event_attrs[] = {
> > +     ARM_CSPMU_EVENT_ATTR(cycles,
> ARM_CSPMU_EVT_CYCLES_DEFAULT),
> > +     NULL,
> > +};
> > +
> > +static struct attribute **
> > +arm_cspmu_get_event_attrs(const struct arm_cspmu *cspmu)
> > +{
> > +     return arm_cspmu_event_attrs;
> > +}
> > +
> > +static umode_t
> > +arm_cspmu_event_attr_is_visible(struct kobject *kobj,
> > +                             struct attribute *attr, int unused)
> > +{
> > +     struct device *dev = kobj_to_dev(kobj);
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(dev_get_drvdata(dev));
> > +     struct perf_pmu_events_attr *eattr;
> > +
> > +     eattr = container_of(attr, typeof(*eattr), attr.attr);
> > +
> > +     /* Hide cycle event if not supported */
> > +     if (!supports_cycle_counter(cspmu) &&
> > +         eattr->id == ARM_CSPMU_EVT_CYCLES_DEFAULT)
> > +             return 0;
> > +
> > +     return attr->mode;
> > +}
> > +
> > +ssize_t arm_cspmu_sysfs_format_show(struct device *dev,
> > +                             struct device_attribute *attr,
> > +                             char *buf)
> > +{
> > +     struct dev_ext_attribute *eattr =
> > +             container_of(attr, struct dev_ext_attribute, attr);
> > +     return sysfs_emit(buf, "%s\n", (char *)eattr->var);
> > +}
> > +EXPORT_SYMBOL_GPL(arm_cspmu_sysfs_format_show);
> > +
> > +static struct attribute *arm_cspmu_format_attrs[] = {
> > +     ARM_CSPMU_FORMAT_EVENT_ATTR,
> > +     ARM_CSPMU_FORMAT_FILTER_ATTR,
> > +     NULL,
> > +};
> > +
> > +static struct attribute **
> > +arm_cspmu_get_format_attrs(const struct arm_cspmu *cspmu)
> > +{
> > +     return arm_cspmu_format_attrs;
> > +}
> > +
> > +static u32 arm_cspmu_event_type(const struct perf_event *event)
> > +{
> > +     return event->attr.config & ARM_CSPMU_EVENT_MASK;
> > +}
> > +
> > +static bool arm_cspmu_is_cycle_counter_event(const struct perf_event
> *event)
> > +{
> > +     return (event->attr.config == ARM_CSPMU_EVT_CYCLES_DEFAULT);
> > +}
> > +
> > +static u32 arm_cspmu_event_filter(const struct perf_event *event)
> > +{
> > +     return event->attr.config1 & ARM_CSPMU_FILTER_MASK;
> > +}
> > +
> > +static ssize_t arm_cspmu_identifier_show(struct device *dev,
> > +                                      struct device_attribute *attr,
> > +                                      char *page)
> > +{
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(dev_get_drvdata(dev));
> > +
> > +     return sysfs_emit(page, "%s\n", cspmu->identifier);
> > +}
> > +
> > +static struct device_attribute arm_cspmu_identifier_attr =
> > +     __ATTR(identifier, 0444, arm_cspmu_identifier_show, NULL);
> > +
> > +static struct attribute *arm_cspmu_identifier_attrs[] = {
> > +     &arm_cspmu_identifier_attr.attr,
> > +     NULL,
> > +};
> > +
> > +static struct attribute_group arm_cspmu_identifier_attr_group = {
> > +     .attrs = arm_cspmu_identifier_attrs,
> > +};
> > +
> > +static const char *arm_cspmu_get_identifier(const struct arm_cspmu
> *cspmu)
> > +{
> > +     const char *identifier =
> > +             devm_kasprintf(cspmu->dev, GFP_KERNEL, "%x",
> > +                            cspmu->impl.pmiidr);
> > +     return identifier;
> > +}
> > +
> > +static const char
> *arm_cspmu_type_str[ACPI_APMT_NODE_TYPE_COUNT] = {
> > +     "mc",
> > +     "smmu",
> > +     "pcie",
> > +     "acpi",
> > +     "cache",
> > +};
> > +
> > +static const char *arm_cspmu_get_name(const struct arm_cspmu
> *cspmu)
> > +{
> > +     struct device *dev;
> > +     struct acpi_apmt_node *apmt_node;
> > +     u8 pmu_type;
> > +     char *name;
> > +     char acpi_hid_string[ACPI_ID_LEN] = { 0 };
> > +     static atomic_t pmu_idx[ACPI_APMT_NODE_TYPE_COUNT] = { 0 };
> > +
> > +     dev = cspmu->dev;
> > +     apmt_node = cspmu->apmt_node;
> > +     pmu_type = apmt_node->type;
> > +
> > +     if (pmu_type >= ACPI_APMT_NODE_TYPE_COUNT) {
> > +             dev_err(dev, "unsupported PMU type-%u\n", pmu_type);
> > +             return NULL;
> > +     }
> > +
> > +     if (pmu_type == ACPI_APMT_NODE_TYPE_ACPI) {
> > +             memcpy(acpi_hid_string,
> > +                     &apmt_node->inst_primary,
> > +                     sizeof(apmt_node->inst_primary));
> > +             name = devm_kasprintf(dev, GFP_KERNEL, "%s_%s_%s_%u",
> PMUNAME,
> > +                                   arm_cspmu_type_str[pmu_type],
> > +                                   acpi_hid_string,
> > +                                   apmt_node->inst_secondary);
> > +     } else {
> > +             name = devm_kasprintf(dev, GFP_KERNEL, "%s_%s_%d",
> PMUNAME,
> > +                                   arm_cspmu_type_str[pmu_type],
> > +                                   atomic_fetch_inc(&pmu_idx[pmu_type]));
> > +     }
> > +
> > +     return name;
> > +}
> > +
> > +static ssize_t arm_cspmu_cpumask_show(struct device *dev,
> > +                                   struct device_attribute *attr,
> > +                                   char *buf)
> > +{
> > +     struct pmu *pmu = dev_get_drvdata(dev);
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(pmu);
> > +     struct dev_ext_attribute *eattr =
> > +             container_of(attr, struct dev_ext_attribute, attr);
> > +     unsigned long mask_id = (unsigned long)eattr->var;
> > +     const cpumask_t *cpumask;
> > +
> > +     switch (mask_id) {
> > +     case ARM_CSPMU_ACTIVE_CPU_MASK:
> > +             cpumask = &cspmu->active_cpu;
> > +             break;
> > +     case ARM_CSPMU_ASSOCIATED_CPU_MASK:
> > +             cpumask = &cspmu->associated_cpus;
> > +             break;
> > +     default:
> > +             return 0;
> > +     }
> > +     return cpumap_print_to_pagebuf(true, buf, cpumask);
> > +}
> > +
> > +static struct attribute *arm_cspmu_cpumask_attrs[] = {
> > +     ARM_CSPMU_CPUMASK_ATTR(cpumask,
> ARM_CSPMU_ACTIVE_CPU_MASK),
> > +     ARM_CSPMU_CPUMASK_ATTR(associated_cpus,
> ARM_CSPMU_ASSOCIATED_CPU_MASK),
> > +     NULL,
> > +};
> > +
> > +static struct attribute_group arm_cspmu_cpumask_attr_group = {
> > +     .attrs = arm_cspmu_cpumask_attrs,
> > +};
> > +
> > +struct impl_match {
> > +     u32 pmiidr;
> > +     u32 mask;
> > +     int (*impl_init_ops)(struct arm_cspmu *cspmu);
> > +};
> > +
> > +static const struct impl_match impl_match[] = {
> > +     {}
> > +};
> > +
> > +static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)
> > +{
> > +     int ret;
> > +     struct acpi_apmt_node *apmt_node = cspmu->apmt_node;
> > +     struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;
> > +     const struct impl_match *match = impl_match;
> > +
> > +     /*
> > +      * Get PMU implementer and product id from APMT node.
> > +      * If APMT node doesn't have implementer/product id, try get it
> > +      * from PMIIDR.
> > +      */
> > +     cspmu->impl.pmiidr =
> > +             (apmt_node->impl_id) ? apmt_node->impl_id :
> > +                                    readl(cspmu->base0 + PMIIDR);
> > +
> > +     /* Find implementer specific attribute ops. */
> > +     for (; match->pmiidr; match++) {
> > +             const u32 mask = match->mask;
> > +
> > +             if ((match->pmiidr & mask) == (cspmu->impl.pmiidr & mask)) {
> > +                     ret = match->impl_init_ops(cspmu);
> > +                     if (ret)
> > +                             return ret;
> > +
> > +                     break;
> > +             }
> > +     }
> > +
> > +     /* Use default callbacks if implementer doesn't provide one. */
> > +     CHECK_DEFAULT_IMPL_OPS(impl_ops, get_event_attrs);
> > +     CHECK_DEFAULT_IMPL_OPS(impl_ops, get_format_attrs);
> > +     CHECK_DEFAULT_IMPL_OPS(impl_ops, get_identifier);
> > +     CHECK_DEFAULT_IMPL_OPS(impl_ops, get_name);
> > +     CHECK_DEFAULT_IMPL_OPS(impl_ops, is_cycle_counter_event);
> > +     CHECK_DEFAULT_IMPL_OPS(impl_ops, event_type);
> > +     CHECK_DEFAULT_IMPL_OPS(impl_ops, event_filter);
> > +     CHECK_DEFAULT_IMPL_OPS(impl_ops, event_attr_is_visible);
> > +
> > +     return 0;
> > +}
> > +
> > +static struct attribute_group *
> > +arm_cspmu_alloc_event_attr_group(struct arm_cspmu *cspmu)
> > +{
> > +     struct attribute_group *event_group;
> > +     struct device *dev = cspmu->dev;
> > +     const struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;
> > +
> > +     event_group =
> > +             devm_kzalloc(dev, sizeof(struct attribute_group), GFP_KERNEL);
> > +     if (!event_group)
> > +             return NULL;
> > +
> > +     event_group->name = "events";
> > +     event_group->attrs = impl_ops->get_event_attrs(cspmu);
> > +     event_group->is_visible = impl_ops->event_attr_is_visible;
> > +
> > +     return event_group;
> > +}
> > +
> > +static struct attribute_group *
> > +arm_cspmu_alloc_format_attr_group(struct arm_cspmu *cspmu)
> > +{
> > +     struct attribute_group *format_group;
> > +     struct device *dev = cspmu->dev;
> > +
> > +     format_group =
> > +             devm_kzalloc(dev, sizeof(struct attribute_group), GFP_KERNEL);
> > +     if (!format_group)
> > +             return NULL;
> > +
> > +     format_group->name = "format";
> > +     format_group->attrs = cspmu->impl.ops.get_format_attrs(cspmu);
> > +
> > +     return format_group;
> > +}
> > +
> > +static struct attribute_group **
> > +arm_cspmu_alloc_attr_group(struct arm_cspmu *cspmu)
> > +{
> > +     struct attribute_group **attr_groups = NULL;
> > +     struct device *dev = cspmu->dev;
> > +     const struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;
> > +     int ret;
> > +
> > +     ret = arm_cspmu_init_impl_ops(cspmu);
> > +     if (ret)
> > +             return NULL;
> > +
> > +     cspmu->identifier = impl_ops->get_identifier(cspmu);
> > +     cspmu->name = impl_ops->get_name(cspmu);
> > +
> > +     if (!cspmu->identifier || !cspmu->name)
> > +             return NULL;
> > +
> > +     attr_groups = devm_kcalloc(dev, 5, sizeof(struct attribute_group *),
> > +                                GFP_KERNEL);
> > +     if (!attr_groups)
> > +             return NULL;
> > +
> > +     attr_groups[0] = arm_cspmu_alloc_event_attr_group(cspmu);
> > +     attr_groups[1] = arm_cspmu_alloc_format_attr_group(cspmu);
> > +     attr_groups[2] = &arm_cspmu_identifier_attr_group;
> > +     attr_groups[3] = &arm_cspmu_cpumask_attr_group;
> > +
> > +     if (!attr_groups[0] || !attr_groups[1])
> > +             return NULL;
> > +
> > +     return attr_groups;
> > +}
> > +
> > +static inline void arm_cspmu_reset_counters(struct arm_cspmu *cspmu)
> > +{
> > +     u32 pmcr = 0;
> > +
> > +     pmcr |= PMCR_P;
> > +     pmcr |= PMCR_C;
> > +     writel(pmcr, cspmu->base0 + PMCR);
> > +}
> > +
> > +static inline void arm_cspmu_start_counters(struct arm_cspmu *cspmu)
> > +{
> > +     writel(PMCR_E, cspmu->base0 + PMCR);
> > +}
> > +
> > +static inline void arm_cspmu_stop_counters(struct arm_cspmu *cspmu)
> > +{
> > +     writel(0, cspmu->base0 + PMCR);
> > +}
> > +
> > +static void arm_cspmu_enable(struct pmu *pmu)
> > +{
> > +     bool disabled;
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(pmu);
> > +
> > +     disabled = bitmap_empty(cspmu->hw_events.used_ctrs,
> > +                             cspmu->num_logical_ctrs);
> > +
> > +     if (disabled)
> > +             return;
> > +
> > +     arm_cspmu_start_counters(cspmu);
> > +}
> > +
> > +static void arm_cspmu_disable(struct pmu *pmu)
> > +{
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(pmu);
> > +
> > +     arm_cspmu_stop_counters(cspmu);
> > +}
> > +
> > +static int arm_cspmu_get_event_idx(struct arm_cspmu_hw_events
> *hw_events,
> > +                             struct perf_event *event)
> > +{
> > +     int idx;
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
> > +
> > +     if (supports_cycle_counter(cspmu)) {
> > +             if (cspmu->impl.ops.is_cycle_counter_event(event)) {
> > +                     /* Search for available cycle counter. */
> > +                     if (test_and_set_bit(cspmu->cycle_counter_logical_idx,
> > +                                          hw_events->used_ctrs))
> > +                             return -EAGAIN;
> > +
> > +                     return cspmu->cycle_counter_logical_idx;
> > +             }
> > +
> > +             /*
> > +              * Search a regular counter from the used counter bitmap.
> > +              * The cycle counter divides the bitmap into two parts. Search
> > +              * the first then second half to exclude the cycle counter bit.
> > +              */
> > +             idx = find_first_zero_bit(hw_events->used_ctrs,
> > +                                       cspmu->cycle_counter_logical_idx);
> > +             if (idx >= cspmu->cycle_counter_logical_idx) {
> > +                     idx = find_next_zero_bit(
> > +                             hw_events->used_ctrs,
> > +                             cspmu->num_logical_ctrs,
> > +                             cspmu->cycle_counter_logical_idx + 1);
> > +             }
> > +     } else {
> > +             idx = find_first_zero_bit(hw_events->used_ctrs,
> > +                                       cspmu->num_logical_ctrs);
> > +     }
> > +
> > +     if (idx >= cspmu->num_logical_ctrs)
> > +             return -EAGAIN;
> > +
> > +     set_bit(idx, hw_events->used_ctrs);
> > +
> > +     return idx;
> > +}
> > +
> > +static bool arm_cspmu_validate_event(struct pmu *pmu,
> > +                              struct arm_cspmu_hw_events *hw_events,
> > +                              struct perf_event *event)
> > +{
> > +     if (is_software_event(event))
> > +             return true;
> > +
> > +     /* Reject groups spanning multiple HW PMUs. */
> > +     if (event->pmu != pmu)
> > +             return false;
> > +
> > +     return (arm_cspmu_get_event_idx(hw_events, event) >= 0);
> > +}
> > +
> > +/*
> > + * Make sure the group of events can be scheduled at once
> > + * on the PMU.
> > + */
> > +static bool arm_cspmu_validate_group(struct perf_event *event)
> > +{
> > +     struct perf_event *sibling, *leader = event->group_leader;
> > +     struct arm_cspmu_hw_events fake_hw_events;
> > +
> > +     if (event->group_leader == event)
> > +             return true;
> > +
> > +     memset(&fake_hw_events, 0, sizeof(fake_hw_events));
> > +
> > +     if (!arm_cspmu_validate_event(event->pmu, &fake_hw_events,
> leader))
> > +             return false;
> > +
> > +     for_each_sibling_event(sibling, leader) {
> > +             if (!arm_cspmu_validate_event(event->pmu, &fake_hw_events,
> > +                                               sibling))
> > +                     return false;
> > +     }
> > +
> > +     return arm_cspmu_validate_event(event->pmu, &fake_hw_events,
> event);
> > +}
> > +
> > +static int arm_cspmu_event_init(struct perf_event *event)
> > +{
> > +     struct arm_cspmu *cspmu;
> > +     struct hw_perf_event *hwc = &event->hw;
> > +
> > +     cspmu = to_arm_cspmu(event->pmu);
> > +
> > +     /*
> > +      * Following other "uncore" PMUs, we do not support sampling mode
> or
> > +      * attach to a task (per-process mode).
> > +      */
> > +     if (is_sampling_event(event)) {
> > +             dev_dbg(cspmu->pmu.dev,
> > +                     "Can't support sampling events\n");
> > +             return -EOPNOTSUPP;
> > +     }
> > +
> > +     if (event->cpu < 0 || event->attach_state & PERF_ATTACH_TASK) {
> > +             dev_dbg(cspmu->pmu.dev,
> > +                     "Can't support per-task counters\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     /*
> > +      * Make sure the CPU assignment is on one of the CPUs associated with
> > +      * this PMU.
> > +      */
> > +     if (!cpumask_test_cpu(event->cpu, &cspmu->associated_cpus)) {
> > +             dev_dbg(cspmu->pmu.dev,
> > +                     "Requested cpu is not associated with the PMU\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     /* Enforce the current active CPU to handle the events in this PMU. */
> > +     event->cpu = cpumask_first(&cspmu->active_cpu);
> > +     if (event->cpu >= nr_cpu_ids)
> > +             return -EINVAL;
> > +
> > +     if (!arm_cspmu_validate_group(event))
> > +             return -EINVAL;
> > +
> > +     /*
> > +      * The logical counter id is tracked with hw_perf_event.extra_reg.idx.
> > +      * The physical counter id is tracked with hw_perf_event.idx.
> > +      * We don't assign an index until we actually place the event onto
> > +      * hardware. Use -1 to signify that we haven't decided where to put it
> > +      * yet.
> > +      */
> > +     hwc->idx = -1;
> > +     hwc->extra_reg.idx = -1;
> > +     hwc->config = cspmu->impl.ops.event_type(event);
> > +
> > +     return 0;
> > +}
> > +
> > +static inline u32 counter_offset(u32 reg_sz, u32 ctr_idx)
> > +{
> > +     return (PMEVCNTR_LO + (reg_sz * ctr_idx));
> > +}
> > +
> > +static void arm_cspmu_write_counter(struct perf_event *event, u64 val)
> > +{
> > +     u32 offset;
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
> > +
> > +     if (use_64b_counter_reg(cspmu)) {
> > +             offset = counter_offset(sizeof(u64), event->hw.idx);
> > +
> > +             writeq(val, cspmu->base1 + offset);
> > +     } else {
> > +             offset = counter_offset(sizeof(u32), event->hw.idx);
> > +
> > +             writel(lower_32_bits(val), cspmu->base1 + offset);
> > +     }
> > +}
> > +
> > +static u64 arm_cspmu_read_counter(struct perf_event *event)
> > +{
> > +     u32 offset;
> > +     const void __iomem *counter_addr;
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
> > +
> > +     if (use_64b_counter_reg(cspmu)) {
> > +             offset = counter_offset(sizeof(u64), event->hw.idx);
> > +             counter_addr = cspmu->base1 + offset;
> > +
> > +             return supports_64bit_atomics(cspmu) ?
> > +                            readq(counter_addr) :
> > +                            read_reg64_hilohi(counter_addr);
> > +     }
> > +
> > +     offset = counter_offset(sizeof(u32), event->hw.idx);
> > +     return readl(cspmu->base1 + offset);
> > +}
> > +
> > +/*
> > + * arm_cspmu_set_event_period: Set the period for the counter.
> > + *
> > + * To handle cases of extreme interrupt latency, we program
> > + * the counter with half of the max count for the counters.
> > + */
> > +static void arm_cspmu_set_event_period(struct perf_event *event)
> > +{
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
> > +     u64 val = counter_mask(cspmu) >> 1ULL;
> > +
> > +     local64_set(&event->hw.prev_count, val);
> > +     arm_cspmu_write_counter(event, val);
> > +}
> > +
> > +static void arm_cspmu_enable_counter(struct arm_cspmu *cspmu, int
> idx)
> > +{
> > +     u32 reg_id, reg_bit, inten_off, cnten_off;
> > +
> > +     reg_id = COUNTER_TO_SET_CLR_ID(idx);
> > +     reg_bit = COUNTER_TO_SET_CLR_BIT(idx);
> > +
> > +     inten_off = PMINTENSET + (4 * reg_id);
> > +     cnten_off = PMCNTENSET + (4 * reg_id);
> > +
> > +     writel(BIT(reg_bit), cspmu->base0 + inten_off);
> > +     writel(BIT(reg_bit), cspmu->base0 + cnten_off);
> > +}
> > +
> > +static void arm_cspmu_disable_counter(struct arm_cspmu *cspmu, int
> idx)
> > +{
> > +     u32 reg_id, reg_bit, inten_off, cnten_off;
> > +
> > +     reg_id = COUNTER_TO_SET_CLR_ID(idx);
> > +     reg_bit = COUNTER_TO_SET_CLR_BIT(idx);
> > +
> > +     inten_off = PMINTENCLR + (4 * reg_id);
> > +     cnten_off = PMCNTENCLR + (4 * reg_id);
> > +
> > +     writel(BIT(reg_bit), cspmu->base0 + cnten_off);
> > +     writel(BIT(reg_bit), cspmu->base0 + inten_off);
> > +}
> > +
> > +static void arm_cspmu_event_update(struct perf_event *event)
> > +{
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
> > +     struct hw_perf_event *hwc = &event->hw;
> > +     u64 delta, prev, now;
> > +
> > +     do {
> > +             prev = local64_read(&hwc->prev_count);
> > +             now = arm_cspmu_read_counter(event);
> > +     } while (local64_cmpxchg(&hwc->prev_count, prev, now) != prev);
> > +
> > +     delta = (now - prev) & counter_mask(cspmu);
> > +     local64_add(delta, &event->count);
> > +}
> > +
> > +static inline void arm_cspmu_set_event(struct arm_cspmu *cspmu,
> > +                                     struct hw_perf_event *hwc)
> > +{
> > +     u32 offset = PMEVTYPER + (4 * hwc->idx);
> > +
> > +     writel(hwc->config, cspmu->base0 + offset);
> > +}
> > +
> > +static inline void arm_cspmu_set_ev_filter(struct arm_cspmu *cspmu,
> > +                                        struct hw_perf_event *hwc,
> > +                                        u32 filter)
> > +{
> > +     u32 offset = PMEVFILTR + (4 * hwc->idx);
> > +
> > +     writel(filter, cspmu->base0 + offset);
> > +}
> > +
> > +static inline void arm_cspmu_set_cc_filter(struct arm_cspmu *cspmu, u32
> filter)
> > +{
> > +     u32 offset = PMCCFILTR;
> > +
> > +     writel(filter, cspmu->base0 + offset);
> > +}
> > +
> > +static void arm_cspmu_start(struct perf_event *event, int pmu_flags)
> > +{
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
> > +     struct hw_perf_event *hwc = &event->hw;
> > +     u32 filter;
> > +
> > +     /* We always reprogram the counter */
> > +     if (pmu_flags & PERF_EF_RELOAD)
> > +             WARN_ON(!(hwc->state & PERF_HES_UPTODATE));
> > +
> > +     arm_cspmu_set_event_period(event);
> > +
> > +     filter = cspmu->impl.ops.event_filter(event);
> > +
> > +     if (event->hw.extra_reg.idx == cspmu->cycle_counter_logical_idx) {
> > +             arm_cspmu_set_cc_filter(cspmu, filter);
> > +     } else {
> > +             arm_cspmu_set_event(cspmu, hwc);
> > +             arm_cspmu_set_ev_filter(cspmu, hwc, filter);
> > +     }
> > +
> > +     hwc->state = 0;
> > +
> > +     arm_cspmu_enable_counter(cspmu, hwc->idx);
> > +}
> > +
> > +static void arm_cspmu_stop(struct perf_event *event, int pmu_flags)
> > +{
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
> > +     struct hw_perf_event *hwc = &event->hw;
> > +
> > +     if (hwc->state & PERF_HES_STOPPED)
> > +             return;
> > +
> > +     arm_cspmu_disable_counter(cspmu, hwc->idx);
> > +     arm_cspmu_event_update(event);
> > +
> > +     hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
> > +}
> > +
> > +static inline u32 to_phys_idx(struct arm_cspmu *cspmu, u32 idx)
> > +{
> > +     return (idx == cspmu->cycle_counter_logical_idx) ?
> > +             ARM_CSPMU_CYCLE_CNTR_IDX : idx;
> > +}
> > +
> > +static int arm_cspmu_add(struct perf_event *event, int flags)
> > +{
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
> > +     struct arm_cspmu_hw_events *hw_events = &cspmu->hw_events;
> > +     struct hw_perf_event *hwc = &event->hw;
> > +     int idx;
> > +
> > +     if (WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(),
> > +                                        &cspmu->associated_cpus)))
> > +             return -ENOENT;
> > +
> > +     idx = arm_cspmu_get_event_idx(hw_events, event);
> > +     if (idx < 0)
> > +             return idx;
> > +
> > +     hw_events->events[idx] = event;
> > +     hwc->idx = to_phys_idx(cspmu, idx);
> > +     hwc->extra_reg.idx = idx;
> > +     hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
> > +
> > +     if (flags & PERF_EF_START)
> > +             arm_cspmu_start(event, PERF_EF_RELOAD);
> > +
> > +     /* Propagate changes to the userspace mapping. */
> > +     perf_event_update_userpage(event);
> > +
> > +     return 0;
> > +}
> > +
> > +static void arm_cspmu_del(struct perf_event *event, int flags)
> > +{
> > +     struct arm_cspmu *cspmu = to_arm_cspmu(event->pmu);
> > +     struct arm_cspmu_hw_events *hw_events = &cspmu->hw_events;
> > +     struct hw_perf_event *hwc = &event->hw;
> > +     int idx = hwc->extra_reg.idx;
> > +
> > +     arm_cspmu_stop(event, PERF_EF_UPDATE);
> > +
> > +     hw_events->events[idx] = NULL;
> > +
> > +     clear_bit(idx, hw_events->used_ctrs);
> > +
> > +     perf_event_update_userpage(event);
> > +}
> > +
> > +static void arm_cspmu_read(struct perf_event *event)
> > +{
> > +     arm_cspmu_event_update(event);
> > +}
> > +
> > +static struct arm_cspmu *arm_cspmu_alloc(struct platform_device
> *pdev)
> > +{
> > +     struct acpi_apmt_node *apmt_node;
> > +     struct arm_cspmu *cspmu;
> > +     struct device *dev;
> > +
> > +     dev = &pdev->dev;
> > +     apmt_node = *(struct acpi_apmt_node **)dev_get_platdata(dev);
> > +     if (!apmt_node) {
> > +             dev_err(dev, "failed to get APMT node\n");
> > +             return NULL;
> > +     }
> > +
> > +     cspmu = devm_kzalloc(dev, sizeof(*cspmu), GFP_KERNEL);
> > +     if (!cspmu)
> > +             return NULL;
> > +
> > +     cspmu->dev = dev;
> > +     cspmu->apmt_node = apmt_node;
> > +
> > +     platform_set_drvdata(pdev, cspmu);
> > +
> > +     return cspmu;
> > +}
> > +
> > +static int arm_cspmu_init_mmio(struct arm_cspmu *cspmu)
> > +{
> > +     struct device *dev;
> > +     struct platform_device *pdev;
> > +     struct acpi_apmt_node *apmt_node;
> > +
> > +     dev = cspmu->dev;
> > +     pdev = to_platform_device(dev);
> > +     apmt_node = cspmu->apmt_node;
> > +
> > +     /* Base address for page 0. */
> > +     cspmu->base0 = devm_platform_ioremap_resource(pdev, 0);
> > +     if (IS_ERR(cspmu->base0)) {
> > +             dev_err(dev, "ioremap failed for page-0 resource\n");
> > +             return PTR_ERR(cspmu->base0);
> > +     }
> > +
> > +     /* Base address for page 1 if supported. Otherwise point to page 0. */
> > +     cspmu->base1 = cspmu->base0;
> > +     if (CHECK_APMT_FLAG(apmt_node->flags, DUAL_PAGE, SUPP)) {
> > +             cspmu->base1 = devm_platform_ioremap_resource(pdev, 1);
> > +             if (IS_ERR(cspmu->base1)) {
> > +                     dev_err(dev, "ioremap failed for page-1 resource\n");
> > +                     return PTR_ERR(cspmu->base1);
> > +             }
> > +     }
> > +
> > +     cspmu->pmcfgr = readl(cspmu->base0 + PMCFGR);
> > +
> > +     cspmu->num_logical_ctrs = FIELD_GET(PMCFGR_N, cspmu->pmcfgr) +
> 1;
> > +
> > +     cspmu->cycle_counter_logical_idx = ARM_CSPMU_MAX_HW_CNTRS;
> > +
> > +     if (supports_cycle_counter(cspmu)) {
> > +             /*
> > +              * The last logical counter is mapped to cycle counter if
> > +              * there is a gap between regular and cycle counter. Otherwise,
> > +              * logical and physical have 1-to-1 mapping.
> > +              */
> > +             cspmu->cycle_counter_logical_idx =
> > +                     (cspmu->num_logical_ctrs <= ARM_CSPMU_CYCLE_CNTR_IDX)
> ?
> > +                             cspmu->num_logical_ctrs - 1 :
> > +                             ARM_CSPMU_CYCLE_CNTR_IDX;
> > +     }
> > +
> > +     cspmu->num_set_clr_reg =
> > +             DIV_ROUND_UP(cspmu->num_logical_ctrs,
> > +                             ARM_CSPMU_SET_CLR_COUNTER_NUM);
> > +
> > +     cspmu->hw_events.events =
> > +             devm_kcalloc(dev, cspmu->num_logical_ctrs,
> > +                          sizeof(*cspmu->hw_events.events), GFP_KERNEL);
> > +
> > +     if (!cspmu->hw_events.events)
> > +             return -ENOMEM;
> > +
> > +     return 0;
> > +}
> > +
> > +static inline int arm_cspmu_get_reset_overflow(struct arm_cspmu
> *cspmu,
> > +                                            u32 *pmovs)
> > +{
> > +     int i;
> > +     u32 pmovclr_offset = PMOVSCLR;
> > +     u32 has_overflowed = 0;
> > +
> > +     for (i = 0; i < cspmu->num_set_clr_reg; ++i) {
> > +             pmovs[i] = readl(cspmu->base1 + pmovclr_offset);
> > +             has_overflowed |= pmovs[i];
> > +             writel(pmovs[i], cspmu->base1 + pmovclr_offset);
> > +             pmovclr_offset += sizeof(u32);
> > +     }
> > +
> > +     return has_overflowed != 0;
> > +}
> > +
> > +static irqreturn_t arm_cspmu_handle_irq(int irq_num, void *dev)
> > +{
> > +     int idx, has_overflowed;
> > +     struct perf_event *event;
> > +     struct arm_cspmu *cspmu = dev;
> > +     u32 pmovs[ARM_CSPMU_SET_CLR_MAX_NUM] = { 0 };
> 
> nit: Could we not reuse what we do for hw_events.use_ctrs ?
> 
> i.e, DECLARE_BITMAP(pmovs, ARM_CSPMU_MAX_HW_CNTRS)
> 
> 
> And remove ARM_CSPMU_SET_CLR_MAX_NUM altogether and the cast
> below
> to (unsigned long *).
> 

Sure, I will update the patch with your suggestion.

> With that
> 
> Reviewed-by: Suzuki K Poulose <suzuki.poulose at arm.com>
> 

Thanks!

> Suzuki


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