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Message-ID: <713d8162-dd3c-483c-b984-7707ef8aaa36@linux.alibaba.com>
Date:   Tue, 11 Apr 2023 11:17:59 +0800
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Subject: Re: [PATCH v2 2/3] drivers/perf: add DesignWare PCIe PMU driver
To:     Shuai Xue <xueshuai@linux.alibaba.com>, helgaas@kernel.org,
        yangyicong@huawei.com, will@kernel.org, Jonathan.Cameron@huawei.com
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-pci@vger.kernel.org, rdunlap@infradead.org,
        robin.murphy@arm.com, mark.rutland@arm.com,
        zhuo.song@linux.alibaba.com
References: <20220917121036.14864-1-xueshuai@linux.alibaba.com>
 <20230410031702.68355-3-xueshuai@linux.alibaba.com>
From:   Baolin Wang <baolin.wang@linux.alibaba.com>
In-Reply-To: <20230410031702.68355-3-xueshuai@linux.alibaba.com>
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Precedence: bulk


On 4/10/2023 11:17 AM, Shuai Xue wrote:
> This commit adds the PCIe Performance Monitoring Unit (PMU) driver support
> for T-Head Yitian SoC chip. Yitian is based on the Synopsys PCI Express
> Core controller IP which provides statistics feature. The PMU is not a PCIe
> Root Complex integrated End Point(RCiEP) device but only register counters
> provided by each PCIe Root Port.
> 
> To facilitate collection of statistics the controller provides the
> following two features for each Root Port:
> 
> - Time Based Analysis (RX/TX data throughput and time spent in each
>    low-power LTSSM state)
> - Event counters (Error and Non-Error for lanes)
> 
> Note, only one counter for each type and does not overflow interrupt.
> 
> This driver adds PMU devices for each PCIe Root Port. And the PMU device is
> named based the BDF of Root Port. For example,
> 
>      30:03.0 PCI bridge: Device 1ded:8000 (rev 01)
> 
> the PMU device name for this Root Port is dwc_rootport_3018.
> 
> Example usage of counting PCIe RX TLP data payload (Units of 16 bytes)::
> 
>      $# perf stat -a -e dwc_rootport_3018/Rx_PCIe_TLP_Data_Payload/
> 
> average RX bandwidth can be calculated like this:
> 
>      PCIe TX Bandwidth = PCIE_TX_DATA * 16B / Measure_Time_Window
> 
> Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
> ---
>   drivers/perf/Kconfig        |   7 +
>   drivers/perf/Makefile       |   1 +
>   drivers/perf/dwc_pcie_pmu.c | 877 ++++++++++++++++++++++++++++++++++++
>   3 files changed, 885 insertions(+)
>   create mode 100644 drivers/perf/dwc_pcie_pmu.c
> 
> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
> index 66c259000a44..57bce3880cba 100644
> --- a/drivers/perf/Kconfig
> +++ b/drivers/perf/Kconfig
> @@ -199,6 +199,13 @@ config MARVELL_CN10K_DDR_PMU
>   	  Enable perf support for Marvell DDR Performance monitoring
>   	  event on CN10K platform.
>   
> +config DWC_PCIE_PMU
> +	tristate "Enable Synopsys DesignWare PCIe PMU Support"
> +	depends on ARM64 || (COMPILE_TEST && 64BIT)
> +	help
> +	  Enable perf support for Synopsys DesignWare PCIe PMU Performance
> +	  monitoring event on Yitian 710 platform.
> +
>   source "drivers/perf/arm_cspmu/Kconfig"
>   
>   source "drivers/perf/amlogic/Kconfig"
> diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
> index 13e45da61100..3f233e96524e 100644
> --- a/drivers/perf/Makefile
> +++ b/drivers/perf/Makefile
> @@ -21,5 +21,6 @@ obj-$(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-$(CONFIG_ALIBABA_UNCORE_DRW_PMU) += alibaba_uncore_drw_pmu.o
> +obj-$(CONFIG_DWC_PCIE_PMU) += dwc_pcie_pmu.o
>   obj-$(CONFIG_ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU) += arm_cspmu/
>   obj-$(CONFIG_MESON_DDR_PMU) += amlogic/
> diff --git a/drivers/perf/dwc_pcie_pmu.c b/drivers/perf/dwc_pcie_pmu.c
> new file mode 100644
> index 000000000000..c8c09f120d4e
> --- /dev/null
> +++ b/drivers/perf/dwc_pcie_pmu.c
> @@ -0,0 +1,877 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Synopsys DesignWare PCIe PMU driver
> + *
> + * Copyright (C) 2021, 2022 Alibaba Inc.
> + */
> +
> +#include <linux/pci.h>
> +#include <linux/bitfield.h>
> +#include <linux/bitops.h>
> +#include <linux/cpuhotplug.h>
> +#include <linux/cpumask.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/perf_event.h>
> +#include <linux/platform_device.h>
> +#include <linux/smp.h>
> +#include <linux/sysfs.h>
> +#include <linux/types.h>
> +#define PCI_VENDOR_ID_ALIBABA 0x1ded
> +
> +#define ATTRI_NAME_MAX_SIZE			32
> +#define DWC_PCIE_VSEC_RAS_DES_ID		0x02
> +
> +#define DWC_PCIE_EVENT_CNT_CTL			0x8
> +#define DWC_PCIE_CNT_EVENT_SEL			GENMASK(27, 16)
> +#define DWC_PCIE_CNT_LANE_SEL			GENMASK(11, 8)
> +#define DWC_PCIE_CNT_STATUS			BIT(7)
> +#define DWC_PCIE_CNT_ENABLE			GENMASK(4, 2)
> +#define DWC_PCIE_PER_EVENT_OFF			FIELD_PREP(DWC_PCIE_CNT_ENABLE, 0x1)
> +#define DWC_PCIE_PER_EVENT_ON			FIELD_PREP(DWC_PCIE_CNT_ENABLE, 0x3)
> +#define DWC_PCIE_EVENT_CLEAR			GENMASK(1, 0)
> +#define DWC_PCIE_EVENT_PER_CLEAR		0x1
> +
> +#define DWC_PCIE_EVENT_CNT_DATA			0xC
> +
> +#define DWC_PCIE_TIME_BASED_ANAL_CTL		0x10
> +#define DWC_PCIE_TIME_BASED_REPORT_SEL		GENMASK(31, 24)
> +#define DWC_PCIE_TIME_BASED_DURATION_SEL	GENMASK(15, 8)
> +#define DWC_PCIE_DURATION_MANUAL_CTL		0x0
> +#define DWC_PCIE_DURATION_1MS			0x1
> +#define DWC_PCIE_DURATION_10MS			0x2
> +#define DWC_PCIE_DURATION_100MS			0x3
> +#define DWC_PCIE_DURATION_1S			0x4
> +#define DWC_PCIE_DURATION_2S			0x5
> +#define DWC_PCIE_DURATION_4S			0x6
> +#define DWC_PCIE_DURATION_4US			0xff
> +#define DWC_PCIE_TIME_BASED_CNT_ENABLE		0x1
> +
> +#define DWC_PCIE_TIME_BASED_ANAL_DATA_REG_LOW	0x14
> +#define DWC_PCIE_TIME_BASED_ANAL_DATA_REG_HIGH	0x18
> +
> +/* Event attributes */
> +#define DWC_PCIE_CONFIG_EVENTID			GENMASK(15, 0)
> +#define DWC_PCIE_CONFIG_TYPE			GENMASK(19, 16)
> +#define DWC_PCIE_CONFIG_LANE			GENMASK(27, 20)
> +
> +#define DWC_PCIE_EVENT_ID(event)	FIELD_GET(DWC_PCIE_CONFIG_EVENTID, (event)->attr.config)
> +#define DWC_PCIE_EVENT_TYPE(event)	FIELD_GET(DWC_PCIE_CONFIG_TYPE, (event)->attr.config)
> +#define DWC_PCIE_EVENT_LANE(event)	FIELD_GET(DWC_PCIE_CONFIG_LANE, (event)->attr.config)
> +
> +#define DWC_PCIE_PMU_HAS_REGISTER		1
> +
> +enum dwc_pcie_event_type {
> +	DWC_PCIE_TYPE_INVALID,
> +	DWC_PCIE_TIME_BASE_EVENT,
> +	DWC_PCIE_LANE_EVENT,
> +};
> +
> +struct dwc_event_counters {
> +	const char name[32];
> +	u32 event_id;
> +};
> +
> +struct dwc_pcie_pmu {
> +	struct hlist_node node;
> +	unsigned int on_cpu;
> +	struct pmu pmu;
> +	struct device *dev;
> +};
> +
> +struct dwc_pcie_rp_info {
> +	u32 bdf;
> +	u32 ras_des;
> +	u32 num_lanes;
> +
> +	struct list_head rp_node;
> +	struct pci_dev *pdev;
> +	struct dwc_pcie_pmu pcie_pmu;
> +	u8 pmu_is_register;
> +	struct perf_event *event;
> +
> +	struct dwc_pcie_event_attr *lane_event_attrs;
> +	struct attribute **pcie_pmu_event_attrs;
> +	struct attribute_group pcie_pmu_event_attrs_group;
> +	const struct attribute_group *pcie_pmu_attr_groups[4];
> +};
> +
> +struct dwc_pcie_pmu_priv {
> +	struct device *dev;
> +	u32 pcie_ctrl_num;
> +	struct list_head rp_infos;
> +};
> +
> +#define to_dwc_pcie_pmu(p) (container_of(p, struct dwc_pcie_pmu, pmu))
> +
> +static struct platform_device *dwc_pcie_pmu_dev;
> +static char *event_attr_name = "events";

Since only one place uses the 'event_attr_name' variable, just using the 
"events" string in the code seems more readable.

> +
> +static ssize_t cpumask_show(struct device *dev,
> +					 struct device_attribute *attr,
> +					 char *buf)
> +{
> +	struct dwc_pcie_pmu *pcie_pmu = to_dwc_pcie_pmu(dev_get_drvdata(dev));
> +
> +	return cpumap_print_to_pagebuf(true, buf, cpumask_of(pcie_pmu->on_cpu));
> +}
> +static DEVICE_ATTR_RO(cpumask);
> +
> +#define DEVICE_ATTR_RO(_name) \
> +	struct device_attribute dev_attr_##_name = __ATTR_RO(_name)

There is already a general DEVICE_ATTR_RO macro in linux/device.h, 
please do not add duplicate and confusing macro definition.

> +#define __ATTR_RO(_name) {						\

This also seems a more general macro definition, can you rename it as 
something like 'DWC_PMU_ATTR_RO' or other better name?

> +	.attr	= { .name = __stringify(_name), .mode = 0444 },		\
> +	.show	= _name##_show,						\
> +}
> +#define __ATTR(_name, _mode, _show, _store) {				\

ditto.

> +	.attr = {.name = __stringify(_name),				\
> +		 .mode = VERIFY_OCTAL_PERMISSIONS(_mode) },		\
> +	.show	= _show,						\
> +	.store	= _store,						\
> +}
> +
> +static struct attribute *dwc_pcie_pmu_cpumask_attrs[] = {
> +	&dev_attr_cpumask.attr,
> +	NULL
> +};
> +
> +static struct attribute_group pcie_pmu_cpumask_attrs_group = { > +	.attrs = dwc_pcie_pmu_cpumask_attrs,
> +};
> +
> +struct dwc_pcie_format_attr {
> +	struct device_attribute attr;
> +	u64 field;
> +	int config;
> +};
> +
> +static ssize_t dwc_pcie_pmu_format_show(struct device *dev,
> +					struct device_attribute *attr,
> +					char *buf)
> +{
> +	struct dwc_pcie_format_attr *fmt = container_of(attr, typeof(*fmt), attr);
> +	int lo = __ffs(fmt->field), hi = __fls(fmt->field);
> +
> +	if (lo == hi)
> +		return snprintf(buf, PAGE_SIZE, "config:%d\n", lo);
> +
> +	if (!fmt->config)
> +		return snprintf(buf, PAGE_SIZE, "config:%d-%d\n", lo, hi);
> +
> +	return snprintf(buf, PAGE_SIZE, "config%d:%d-%d\n", fmt->config, lo,
> +			hi);
> +}
> +
> +#define _dwc_pcie_format_attr(_name, _cfg, _fld)				\
> +	(&((struct dwc_pcie_format_attr[]) {{				\
> +		.attr = __ATTR(_name, 0444, dwc_pcie_pmu_format_show, NULL),	\
> +		.config = _cfg,						\
> +		.field = _fld,						\
> +	}})[0].attr.attr)
> +
> +#define dwc_pcie_format_attr(_name, _fld)	_dwc_pcie_format_attr(_name, 0, _fld)
> +
> +static struct attribute *dwc_pcie_format_attrs[] = {
> +	dwc_pcie_format_attr(type, DWC_PCIE_CONFIG_TYPE),
> +	dwc_pcie_format_attr(eventid, DWC_PCIE_CONFIG_EVENTID),
> +	dwc_pcie_format_attr(lane, DWC_PCIE_CONFIG_LANE),
> +	NULL,
> +};
> +
> +static struct attribute_group pcie_pmu_format_attrs_group = { > +	.name = "format",
> +	.attrs = dwc_pcie_format_attrs,
> +};
> +
> +struct dwc_pcie_event_attr {
> +	struct device_attribute attr;
> +	enum dwc_pcie_event_type type;
> +	u16 eventid;
> +	u8 lane;
> +};
> +
> +ssize_t dwc_pcie_event_show(struct device *dev,
> +				struct device_attribute *attr, char *page)
> +{
> +	struct dwc_pcie_event_attr *eattr;
> +
> +	eattr = container_of(attr, typeof(*eattr), attr);
> +
> +	if (eattr->type == DWC_PCIE_LANE_EVENT)
> +		return sprintf(page, "eventid=0x%lx, type=0x%lx, lane=0x%lx\n",
> +			       (unsigned long)eattr->eventid,
> +			       (unsigned long)eattr->type,
> +			       (unsigned long)eattr->lane);
> +	else

'else' is redundant.

> +		return sprintf(page, "eventid=0x%lx, type=0x%lx",
> +			       (unsigned long)eattr->eventid,
> +			       (unsigned long)eattr->type);
> +}
> +
> +#define DWC_PCIE_EVENT_ATTR(_name, _type, _eventid, _lane)		\
> +	(&((struct dwc_pcie_event_attr[]) {{				\
> +		.attr = __ATTR(_name, 0444, dwc_pcie_event_show, NULL),	\
> +		.type = _type,						\
> +		.eventid = _eventid,					\
> +		.lane = _lane,					\
> +	}})[0].attr.attr)
> +
> +#define DWC_PCIE_PMU_BASE_TIME_ATTR(_name, _eventid)			\
> +	DWC_PCIE_EVENT_ATTR(_name, DWC_PCIE_TIME_BASE_EVENT, _eventid, 0)
> +
> +static struct attribute *dwc_pcie_pmu_time_event_attrs[] = {
> +	/* Group #0 */
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(one_cycle, 0x00),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(TX_L0S, 0x01),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(RX_L0S, 0x02),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(L0, 0x03),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(L1, 0x04),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(L1_1, 0x05),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(L1_2, 0x06),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(CFG_RCVRY, 0x07),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(TX_RX_L0S, 0x08),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(L1_AUX, 0x09),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(ONE_cycle, 0x10),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(TX_L0S_, 0x11),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(RX_L0S_, 0x12),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(L0_, 0x13),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(L1_, 0x17),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(CFG_RCVRY_, 0x17),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(TX_RX_L0S_, 0x18),
> +	/* Group #1 */
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(Tx_PCIe_TLP_Data_Payload, 0x20),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(Rx_PCIe_TLP_Data_Payload, 0x21),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(Tx_CCIX_TLP_Data_Payload, 0x22),
> +	DWC_PCIE_PMU_BASE_TIME_ATTR(Rx_CCIX_TLP_Data_Payload, 0x23),
> +	NULL
> +};
> +
> +static inline umode_t pcie_pmu_event_attr_is_visible(struct kobject *kobj,
> +						     struct attribute *attr,
> +						     int unuse)
> +{
> +	return attr->mode;
> +}
> +
> +static inline bool pci_dev_is_rootport(struct pci_dev *pdev)
> +{
> +	return (pci_is_pcie(pdev) &&
> +		pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT);
> +}
> +
> +static int dwc_pcie_ras_des_discover(struct dwc_pcie_pmu_priv *priv)
> +{
> +	int index = 0;
> +	struct pci_dev *pdev = NULL;
> +	struct dwc_pcie_rp_info *rp_info;
> +
> +	INIT_LIST_HEAD(&priv->rp_infos);
> +
> +	/* Match the rootport with VSEC_RAS_DES_ID */
> +	for_each_pci_dev(pdev) {
> +		u16 vsec;
> +		u32 val;
> +
> +		if (!pci_dev_is_rootport(pdev))
> +			continue;
> +
> +		rp_info = devm_kzalloc(&pdev->dev, sizeof(*rp_info), GFP_KERNEL);
> +		if (!rp_info)
> +			return -ENOMEM;
> +
> +		rp_info->bdf = PCI_DEVID(pdev->bus->number, pdev->devfn);
> +		rp_info->pdev = pdev;
> +
> +		vsec = pci_find_vsec_capability(pdev, PCI_VENDOR_ID_ALIBABA,
> +						DWC_PCIE_VSEC_RAS_DES_ID);
> +		if (!vsec)
> +			continue;
> +
> +		pci_read_config_dword(pdev, vsec + PCI_VNDR_HEADER, &val);
> +		if (PCI_VNDR_HEADER_REV(val) != 0x04 ||
> +		    PCI_VNDR_HEADER_LEN(val) != 0x100)
> +			continue;
> +		pci_dbg(pdev,
> +			"Detected PCIe Vendor-Specific Extended Capability RAS DES\n");
> +
> +		rp_info->ras_des = vsec;
> +
> +		pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, &val);

The linkcap value is not used, then why need read it?

> +		rp_info->num_lanes = pcie_get_width_cap(pdev);
> +
> +		list_add(&rp_info->rp_node, &priv->rp_infos);
> +		index++;
> +	}
> +
> +	if (!index)
> +		return -ENODEV;
> +
> +	priv->pcie_ctrl_num = index;
> +
> +	return 0;
> +}
> +
> +static void dwc_pcie_pmu_set_event_id(struct pci_dev *pdev, u16 ras_des,
> +				     int event_id)
> +{
> +	u32 val;
> +
> +	pci_read_config_dword(pdev, ras_des + DWC_PCIE_EVENT_CNT_CTL, &val);
> +
> +	val &= ~DWC_PCIE_CNT_ENABLE;
> +	val |= FIELD_PREP(DWC_PCIE_CNT_EVENT_SEL, event_id);
> +
> +	pci_write_config_dword(pdev, ras_des + DWC_PCIE_EVENT_CNT_CTL, val);
> +}
> +
> +static void dwc_pcie_pmu_write_event_lane(struct pci_dev *pdev, u16 ras_des,
> +					 int lane, int event_id)
> +{
> +	u32 val;
> +
> +	pci_read_config_dword(pdev, ras_des + DWC_PCIE_EVENT_CNT_CTL, &val);
> +
> +	val &= ~DWC_PCIE_CNT_LANE_SEL;
> +	val |= FIELD_PREP(DWC_PCIE_CNT_EVENT_SEL, lane);
> +
> +	pci_write_config_dword(pdev, ras_des + DWC_PCIE_EVENT_CNT_CTL, val);
> +}
> +
> +static void dwc_pcie_pmu_event_enable(struct pci_dev *pdev, u16 ras_des,
> +				     u32 enable)
> +{
> +	u32 val;
> +
> +	pci_read_config_dword(pdev, ras_des + DWC_PCIE_EVENT_CNT_CTL, &val);
> +
> +	val &= ~DWC_PCIE_CNT_ENABLE;
> +
> +	if (enable)
> +		val |= DWC_PCIE_PER_EVENT_ON;
> +	else
> +		val |= DWC_PCIE_PER_EVENT_OFF;
> +
> +	pci_write_config_dword(pdev, ras_des + DWC_PCIE_EVENT_CNT_CTL, val);
> +}
> +
> +static void dwc_pcie_pmu_base_time_enable(struct pci_dev *pdev, u16 ras_des,
> +					 u32 enable)
> +{
> +	u32 val;
> +
> +	pci_read_config_dword(pdev, ras_des + DWC_PCIE_TIME_BASED_ANAL_CTL, &val);
> +
> +	if (enable)
> +		val |= DWC_PCIE_TIME_BASED_CNT_ENABLE;
> +	else
> +		val &= ~DWC_PCIE_TIME_BASED_CNT_ENABLE;
> +
> +	pci_write_config_dword(pdev, ras_des + DWC_PCIE_TIME_BASED_ANAL_CTL, val);
> +}
> +
> +static void dwc_pcie_pmu_read_event_counter(struct pci_dev *pdev, u16 ras_des,
> +					    u64 *counter)
> +{
> +	u32 val;
> +
> +	pci_read_config_dword(pdev, ras_des + DWC_PCIE_EVENT_CNT_DATA, &val);
> +	*counter = val;
> +}
> +
> +/* The results are cleared when next measurement starts. */
> +static void dwc_pcie_pmu_read_base_time_counter(struct pci_dev *pdev,
> +						u16 ras_des, u64 *counter)
> +{
> +	u32 val;
> +
> +	pci_read_config_dword(
> +		pdev, ras_des + DWC_PCIE_TIME_BASED_ANAL_DATA_REG_HIGH,
> +		&val);
> +	*counter = val;
> +	*counter <<= 32;
> +
> +	pci_read_config_dword(
> +		pdev, ras_des + DWC_PCIE_TIME_BASED_ANAL_DATA_REG_LOW,
> +		&val);
> +
> +	*counter += val;
> +}
> +
> +static void dwc_pcie_pmu_clear_event_counter(struct pci_dev *pdev, u16 ras_des)
> +{
> +	u32 val;
> +
> +	pci_read_config_dword(pdev, ras_des + DWC_PCIE_EVENT_CNT_CTL, &val);
> +
> +	val |= FIELD_PREP(DWC_PCIE_EVENT_CLEAR, DWC_PCIE_EVENT_PER_CLEAR);
> +
> +	pci_write_config_dword(pdev, ras_des + DWC_PCIE_EVENT_CNT_CTL, val);
> +}
> +
> +static void dwc_pcie_pmu_base_time_add_prepare(struct pci_dev *pdev,
> +					       u16 ras_des, u32 event_id)
> +{
> +	u32 val;
> +
> +	pci_read_config_dword(pdev, ras_des + DWC_PCIE_TIME_BASED_ANAL_CTL,
> +			      &val);
> +
> +	val &= ~DWC_PCIE_TIME_BASED_REPORT_SEL;
> +	val |= FIELD_PREP(DWC_PCIE_TIME_BASED_REPORT_SEL, event_id);
> +	val &= ~DWC_PCIE_TIME_BASED_DURATION_SEL;
> +
> +	/*
> +	 * TIME_BASED_ANAL_DATA_REG is a 64 bit register, we can safely
> +	 * use it with any manually controlled duration.
> +	 */
> +	val &= ~(DWC_PCIE_TIME_BASED_DURATION_SEL);

Remove redundant '()'.

> +	val |= DWC_PCIE_DURATION_MANUAL_CTL;
> +
> +	pci_write_config_dword(pdev, ras_des + DWC_PCIE_TIME_BASED_ANAL_CTL,
> +			       val);
> +}
> +
> +static struct dwc_pcie_rp_info *pmu_to_pcie_info(struct pmu *pmu)
> +{
> +	struct dwc_pcie_rp_info *rp_info;
> +	struct dwc_pcie_pmu *pcie_pmu = to_dwc_pcie_pmu(pmu);
> +
> +	rp_info = container_of(pcie_pmu, struct dwc_pcie_rp_info, pcie_pmu);
> +
> +	return rp_info;
> +}
> +
> +static void dwc_pcie_pmu_event_update(struct perf_event *event)
> +{
> +	u64 counter;
> +	struct dwc_pcie_pmu *pcie_pmu = to_dwc_pcie_pmu(event->pmu);
> +	struct dwc_pcie_rp_info *rp_info = pmu_to_pcie_info(event->pmu);
> +	struct pci_dev *pdev = rp_info->pdev;
> +	u16 ras_des = rp_info->ras_des;
> +	struct hw_perf_event *hwc = &event->hw;
> +	enum dwc_pcie_event_type type = DWC_PCIE_EVENT_TYPE(event);
> +	u64 delta, prev, now;
> +
> +	do {
> +		prev = local64_read(&hwc->prev_count);
> +
> +		if (type == DWC_PCIE_LANE_EVENT)
> +			dwc_pcie_pmu_read_event_counter(pdev, ras_des, &counter);
> +		else if (type == DWC_PCIE_TIME_BASE_EVENT)
> +			dwc_pcie_pmu_read_base_time_counter(pdev, ras_des,
> +							    &counter);
> +		else
> +			dev_err(pcie_pmu->dev, "invalid event type: 0x%x\n", type);
> +
> +		now = counter;
> +	} while (local64_cmpxchg(&hwc->prev_count, prev, now) != prev);
> +
> +	delta = now - prev;

This can be overflow? better to add a mask to avoid possible overflow.

> +
> +	local64_add(delta, &event->count);
> +}
> +
> +static int dwc_pcie_pmu_event_init(struct perf_event *event)
> +{
> +	struct hw_perf_event *hwc = &event->hw;
> +	struct dwc_pcie_pmu *pcie_pmu = to_dwc_pcie_pmu(event->pmu);
> +	struct perf_event *sibling;
> +
> +	if (event->attr.type != event->pmu->type)
> +		return -ENOENT;
> +
> +	if (hwc->sample_period) {
> +		dev_dbg(pcie_pmu->dev, "Sampling not supported\n");

should use dev_err() if treating it as an error.

> +		return -EOPNOTSUPP;
> +	}
> +
> +	if (event->cpu < 0) {
> +		dev_dbg(pcie_pmu->dev, "Per-task mode not supported\n");

ditto.

> +		return -EOPNOTSUPP;
> +	}
> +
> +	event->cpu = pcie_pmu->on_cpu;
> +
> +	if (event->group_leader != event &&
> +	    !is_software_event(event->group_leader))
> +		return -EINVAL;
> +
> +	for_each_sibling_event(sibling, event->group_leader) {
> +		if (sibling != event && !is_software_event(sibling))
> +			return -EINVAL;
> +	}
> +
> +	hwc->idx = -1;
> +
> +	return 0;
> +}
> +
> +static void dwc_pcie_pmu_set_period(struct hw_perf_event *hwc)
> +{
> +	local64_set(&hwc->prev_count, 0);
> +}
> +
> +static void dwc_pcie_pmu_event_start(struct perf_event *event, int flags)
> +{
> +	struct hw_perf_event *hwc = &event->hw;
> +	struct dwc_pcie_pmu *pcie_pmu = to_dwc_pcie_pmu(event->pmu);
> +	struct dwc_pcie_rp_info *rp_info = pmu_to_pcie_info(event->pmu);
> +	struct pci_dev *pdev = rp_info->pdev;
> +	u16 ras_des = rp_info->ras_des;
> +	enum dwc_pcie_event_type type = DWC_PCIE_EVENT_TYPE(event);
> +
> +	hwc->state = 0;
> +	dwc_pcie_pmu_set_period(hwc);
> +
> +	if (type == DWC_PCIE_LANE_EVENT)
> +		dwc_pcie_pmu_event_enable(pdev, ras_des, 1);
> +	else if (type == DWC_PCIE_TIME_BASE_EVENT)
> +		dwc_pcie_pmu_base_time_enable(pdev, ras_des, 1);
> +	else
> +		dev_err(pcie_pmu->dev, "invalid event type: 0x%x\n", type);
> +}
> +
> +static void dwc_pcie_pmu_event_stop(struct perf_event *event, int flags)
> +{
> +	struct dwc_pcie_pmu *pcie_pmu = to_dwc_pcie_pmu(event->pmu);
> +	struct dwc_pcie_rp_info *rp_info = pmu_to_pcie_info(event->pmu);
> +	struct pci_dev *pdev = rp_info->pdev;
> +	u16 ras_des = rp_info->ras_des;
> +
> +	enum dwc_pcie_event_type type = DWC_PCIE_EVENT_TYPE(event);
> +
> +	if (event->hw.state & PERF_HES_STOPPED)
> +		return;
> +
> +	if (type == DWC_PCIE_LANE_EVENT)
> +		dwc_pcie_pmu_event_enable(pdev, ras_des, 0);
> +	else if (type == DWC_PCIE_TIME_BASE_EVENT)
> +		dwc_pcie_pmu_base_time_enable(pdev, ras_des, 0);
> +	else
> +		dev_err(pcie_pmu->dev, "invalid event type: 0x%x\n", type);
> +
> +	dwc_pcie_pmu_event_update(event);
> +}
> +
> +static int dwc_pcie_pmu_event_add(struct perf_event *event, int flags)
> +{
> +	struct dwc_pcie_pmu *pcie_pmu = to_dwc_pcie_pmu(event->pmu);
> +	struct dwc_pcie_rp_info *rp_info = pmu_to_pcie_info(event->pmu);
> +	struct pci_dev *pdev = rp_info->pdev;
> +	u16 ras_des = rp_info->ras_des;
> +	struct hw_perf_event *hwc = &event->hw;
> +	enum dwc_pcie_event_type type = DWC_PCIE_EVENT_TYPE(event);
> +	int event_id = DWC_PCIE_EVENT_ID(event);
> +	int lane = DWC_PCIE_EVENT_LANE(event);
> +
> +	/* Only one counter and it is in use */
> +	if (rp_info->event)
> +		return -ENOSPC;
> +
> +	rp_info->event = event;
> +
> +	hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
> +
> +	if (type == DWC_PCIE_LANE_EVENT) {
> +		dwc_pcie_pmu_event_enable(pdev, ras_des, 0);
> +		dwc_pcie_pmu_write_event_lane(pdev, ras_des, lane, event_id);
> +		dwc_pcie_pmu_set_event_id(pdev, ras_des, event_id);
> +		dwc_pcie_pmu_clear_event_counter(pdev, ras_des);
> +	} else if (type == DWC_PCIE_TIME_BASE_EVENT) {
> +		dwc_pcie_pmu_base_time_enable(pdev, ras_des, 0);
> +		dwc_pcie_pmu_base_time_add_prepare(pdev, ras_des, event_id);
> +	} else {
> +		dev_err(pcie_pmu->dev, "invalid event type: 0x%x\n", type);
> +		return -EINVAL;
> +	}
> +
> +	if (flags & PERF_EF_START)
> +		dwc_pcie_pmu_event_start(event, PERF_EF_RELOAD);
> +
> +	perf_event_update_userpage(event);
> +
> +	return 0;
> +}
> +
> +static void dwc_pcie_pmu_event_del(struct perf_event *event, int flags)
> +{
> +	struct dwc_pcie_rp_info *rp_info = pmu_to_pcie_info(event->pmu);
> +
> +	dwc_pcie_pmu_event_stop(event, flags | PERF_EF_UPDATE);
> +	perf_event_update_userpage(event);
> +	rp_info->event = NULL;
> +}
> +
> +static void dwc_pcie_pmu_event_read(struct perf_event *event)
> +{
> +	dwc_pcie_pmu_event_update(event);
> +}
> +
> +static struct dwc_event_counters event_array[] = {
> +	{"tx_ack_dllp", 0x600},
> +	{"tx_update_fc_dllp", 0x601},
> +	{"rx_ack_dllp", 0x602},
> +	{"rx_update_fc_dllp", 0x603},
> +	{"rx_nulified_tlp", 0x604},
> +	{"tx_nulified_tlp", 0x605},
> +	{"rx_duplicate_tlp", 0x606},
> +	{"tx_memory_write", 0x700},
> +	{"tx_memory_read", 0x701},
> +	{"tx_configuration_write", 0x702},
> +	{"tx_configuration_read", 0x703},
> +	{"tx_io_write", 0x704},
> +	{"tx_io_read", 0x705},
> +	{"tx_completion_without_data", 0x706},
> +	{"tx_completion_with_data", 0x707},
> +	{"tx_message_tlp", 0x708},
> +	{"tx_atomic", 0x709},
> +	{"tx_tlp_with_prefix", 0x70A},
> +	{"rx_memory_write", 0x70B},
> +	{"rx_memory_read", 0x70C},
> +	{"rx_io_write", 0x70F},
> +	{"rx_io_read", 0x710},
> +	{"rx_completion_without_data", 0x711},
> +	{"rx_completion_with_data", 0x712},
> +	{"rx_message_tlp", 0x713},
> +	{"rx_atomic", 0x714},
> +	{"rx_tlp_with_prefix", 0x715},
> +	{"tx_ccix_tlp", 0x716},
> +	{"rx_ccix_tlp", 0x717},
> +};
> +
> +static int dwc_pcie_pmu_attr_init(struct dwc_pcie_pmu_priv *priv,
> +				  struct dwc_pcie_rp_info *rp_info)
> +{
> +	int i, j;
> +	char lane[8];
> +	const char tmp[64];
> +	int events_per_lane;
> +	int num_lane_events;
> +	int time_base_count;
> +	int num_attrs, attr_idx;
> +	struct dwc_pcie_event_attr *lane_attrs;
> +	struct attribute **pmu_attrs;
> +
> +	memset((void *)tmp, 0, sizeof(tmp));
> +	memset((void *)lane, 0, sizeof(lane));
> +	time_base_count = ARRAY_SIZE(dwc_pcie_pmu_time_event_attrs);
> +	events_per_lane = ARRAY_SIZE(event_array);
> +	num_lane_events = rp_info->num_lanes * events_per_lane;
> +	num_attrs = time_base_count + num_lane_events;
> +
> +	rp_info->lane_event_attrs =
> +		devm_kcalloc(priv->dev, num_lane_events,
> +				sizeof(struct dwc_pcie_event_attr),
> +				GFP_KERNEL);
> +	if (!rp_info->lane_event_attrs)
> +		return -ENOMEM;
> +	lane_attrs = rp_info->lane_event_attrs;
> +	rp_info->pcie_pmu_event_attrs =
> +		devm_kcalloc(priv->dev, num_attrs, sizeof(struct attribute *),
> +			 GFP_KERNEL);
> +	if (!rp_info->pcie_pmu_event_attrs)
> +		return -ENOMEM;
> +	pmu_attrs = rp_info->pcie_pmu_event_attrs;
> +
> +	for (i = 0; i < num_lane_events; i++) {
> +		lane_attrs[i].attr.attr.name =
> +		    devm_kzalloc(priv->dev, sizeof(char)
> +				 * ATTRI_NAME_MAX_SIZE, GFP_KERNEL);
> +		if (!lane_attrs[i].attr.attr.name)
> +			return -ENOMEM;
> +	}
> +
> +	attr_idx = 0;
> +	for (i = 0; i < rp_info->num_lanes; i++) {
> +		sprintf(lane, "_lane%d", i);
> +
> +		for (j = 0; j < events_per_lane; j++) {
> +			int pos = i * events_per_lane + j;
> +
> +			strcat((char *)tmp, event_array[j].name);
> +			strcat((char *)tmp, lane);
> +			memcpy((void *)lane_attrs[pos].attr.attr.name,
> +			       (void *)tmp,
> +			       sizeof(tmp));
> +
> +			lane_attrs[pos].attr.attr.mode =
> +			    VERIFY_OCTAL_PERMISSIONS(0444);
> +			lane_attrs[pos].attr.show = dwc_pcie_event_show;
> +			lane_attrs[pos].attr.store = NULL;
> +			lane_attrs[pos].type = DWC_PCIE_LANE_EVENT;
> +			lane_attrs[pos].eventid = event_array[j].event_id;
> +			lane_attrs[pos].lane = i;
> +			pmu_attrs[attr_idx++] = &lane_attrs[pos].attr.attr;
> +
> +			memset((void *)tmp, 0, sizeof(tmp));
> +		}
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(dwc_pcie_pmu_time_event_attrs); i++)
> +		pmu_attrs[attr_idx++] = dwc_pcie_pmu_time_event_attrs[i];
> +
> +	rp_info->pcie_pmu_event_attrs[attr_idx++] = NULL;
> +
> +	rp_info->pcie_pmu_event_attrs_group.name = event_attr_name;
> +	rp_info->pcie_pmu_event_attrs_group.is_visible =
> +	    pcie_pmu_event_attr_is_visible;
> +	rp_info->pcie_pmu_event_attrs_group.attrs =
> +	    rp_info->pcie_pmu_event_attrs;
> +
> +	rp_info->pcie_pmu_attr_groups[0] =
> +	    &rp_info->pcie_pmu_event_attrs_group;
> +	rp_info->pcie_pmu_attr_groups[1] = &pcie_pmu_format_attrs_group;
> +	rp_info->pcie_pmu_attr_groups[2] = &pcie_pmu_cpumask_attrs_group;
> +	rp_info->pcie_pmu_attr_groups[3] = NULL;
> +
> +	return 0;
> +}
> +
> +static int __dwc_pcie_pmu_probe(struct dwc_pcie_pmu_priv *priv,
> +				struct dwc_pcie_rp_info *rp_info)
> +{
> +	struct dwc_pcie_pmu *pcie_pmu;
> +	struct device *dev;
> +	char *name;
> +	int ret;
> +
> +	pcie_pmu = &rp_info->pcie_pmu;
> +	dev = &rp_info->pdev->dev;
> +
> +	ret = dwc_pcie_pmu_attr_init(priv, rp_info);
> +	if (ret) {
> +		pci_err(rp_info->pdev, "PMU attr init fail ret=%d\n", ret);
> +		return ret;
> +	}
> +
> +	pcie_pmu->dev = dev;
> +	pcie_pmu->pmu = (struct pmu) {
> +		.module		= THIS_MODULE,
> +		.task_ctx_nr	= perf_invalid_context,
> +		.pmu_enable	= NULL,
> +		.pmu_disable	= NULL,
> +		.event_init	= dwc_pcie_pmu_event_init,
> +		.add		= dwc_pcie_pmu_event_add,
> +		.del		= dwc_pcie_pmu_event_del,
> +		.start		= dwc_pcie_pmu_event_start,
> +		.stop		= dwc_pcie_pmu_event_stop,
> +		.read		= dwc_pcie_pmu_event_read,
> +		.attr_groups	= rp_info->pcie_pmu_attr_groups,
> +		.capabilities	= PERF_PMU_CAP_NO_EXCLUDE,
> +	};
> +
> +	name = devm_kasprintf(priv->dev, GFP_KERNEL, "dwc_rootport_%x",
> +			      rp_info->bdf);
> +	if (!name)
> +		return -ENOMEM;
> +
> +	/*
> +	 * Pick one CPU to be the preferred one on local NUMA node.
> +	 *
> +	 * Note, this PMU does NOT support interrupt, set on_cpu to indicate it
> +	 * is a uncore PMU device.
> +	 */
> +	pcie_pmu->on_cpu = cpumask_local_spread(0, dev_to_node(pcie_pmu->dev));
> +	ret = perf_pmu_register(&pcie_pmu->pmu, name, -1);
> +	if (ret) {
> +		pci_err(rp_info->pdev, "Error %d registering PMU @%x\n", ret,
> +				 rp_info->bdf);
> +		return ret;
> +	}
> +
> +	rp_info->pmu_is_register = DWC_PCIE_PMU_HAS_REGISTER;

Seems a boolean type, and no need define another macro.

> +
> +	return ret;

return 0;

> +}
> +
> +static int dwc_pcie_pmu_remove(struct platform_device *pdev)
> +{
> +	struct dwc_pcie_pmu_priv *priv = platform_get_drvdata(pdev);
> +	struct dwc_pcie_pmu *pcie_pmu;
> +	struct dwc_pcie_rp_info *rp_info;
> +
> +	list_for_each_entry(rp_info, &priv->rp_infos, rp_node) {
> +		if (rp_info->pmu_is_register) {
> +			pcie_pmu = &rp_info->pcie_pmu;
> +			perf_pmu_unregister(&pcie_pmu->pmu);
> +		}
> +	}
> +	return 0;
> +}
> +
> +static int dwc_pcie_pmu_probe(struct platform_device *pdev)
> +{
> +	int ret;
> +	struct dwc_pcie_pmu_priv *priv;
> +	struct dwc_pcie_rp_info *rp_info;
> +
> +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->dev = &pdev->dev;
> +	platform_set_drvdata(pdev, priv);
> +
> +	/* If RAS_DES PMU is not supported on current platform, keep silent */
> +	ret = dwc_pcie_ras_des_discover(priv);
> +	if (ret)
> +		return ret;
> +
> +	list_for_each_entry(rp_info, &priv->rp_infos, rp_node) {
> +		struct pci_dev *rp = rp_info->pdev;
> +
> +		ret = __dwc_pcie_pmu_probe(priv, rp_info);
> +		if (ret) {
> +			dev_err(&rp->dev, "PCIe PMU probe fail\n");
> +			goto pmu_unregister;
> +		}
> +	}
> +
> +	return 0;
> +
> +pmu_unregister:
> +	dwc_pcie_pmu_remove(pdev);
> +
> +	return ret;
> +}
> +
> +static struct platform_driver dwc_pcie_pmu_driver = {
> +	.probe = dwc_pcie_pmu_probe,
> +	.remove = dwc_pcie_pmu_remove,
> +	.driver = {.name = "dwc_pcie_pmu",},
> +};
> +
> +static int __init dwc_pcie_pmu_init(void)
> +{
> +	int ret;
> +
> +	ret = platform_driver_register(&dwc_pcie_pmu_driver);
> +
> +	if (ret)
> +		return ret;
> +
> +	dwc_pcie_pmu_dev =
> +	    platform_device_register_simple("dwc_pcie_pmu", -1, NULL, 0);

You can use PLATFORM_DEVID_NONE macro instead of the magic number '-1'.

> +	if (IS_ERR(dwc_pcie_pmu_dev)) {
> +		platform_driver_unregister(&dwc_pcie_pmu_driver);
> +		return PTR_ERR(dwc_pcie_pmu_dev);
> +	}
> +
> +	return 0;
> +}
> +
> +static void __exit dwc_pcie_pmu_exit(void)
> +{
> +	platform_device_unregister(dwc_pcie_pmu_dev);
> +	platform_driver_unregister(&dwc_pcie_pmu_driver);
> +}
> +
> +module_init(dwc_pcie_pmu_init);
> +module_exit(dwc_pcie_pmu_exit);
> +
> +MODULE_DESCRIPTION("PMU driver for DesignWare Cores PCI Express Controller");
> +MODULE_AUTHOR("xueshuai@linux.alibaba.com");

Please correct the format for module author:
MODULE_AUTHOR("Xue Shuai <xueshuai@linux.alibaba.com>");

> +MODULE_AUTHOR("yinxuan_cw@linux.alibaba.com");
> +MODULE_LICENSE("GPL v2");