On 2023/8/1 19:46, Yicong Yang wrote: > On 2023/7/28 20:41, Shuai Xue wrote: >> >> >> On 2023/7/27 17:39, Jonathan Cameron wrote: >>> On Tue, 6 Jun 2023 23:14:07 +0800 >>> Yicong Yang <yangyicong@xxxxxxxxxx> wrote: >>> >>>> On 2023/6/6 15:49, 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@xxxxxxxxxxxxxxxxx> >>>>> Reported-by: kernel test robot <lkp@xxxxxxxxx> >>>>> Link: https://lore.kernel.org/oe-kbuild-all/202305170639.XU3djFZX-lkp@xxxxxxxxx/ >>>>> Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> >>> >>> I'll review on top to avoid any duplication with Yicong. >> >> Thank you! It also served as a reminder that I missed Yicong's email. It appears >> that Thunderbird mistakenly moved his email to the junk folder, resulting in me >> overlooking it. >> >>> >>> Note I've cropped the stuff neither of us commented on so it's >>> easier to spot the feedback. >> >> Thank you for noting that. My feedback is replied inline. >> >>> >>> Jonathan >>> >>>>> --- >>>>> drivers/perf/Kconfig | 7 + >>>>> drivers/perf/Makefile | 1 + >>>>> drivers/perf/dwc_pcie_pmu.c | 706 ++++++++++++++++++++++++++++++++++++ >>>>> 3 files changed, 714 insertions(+) >>>>> create mode 100644 drivers/perf/dwc_pcie_pmu.c >>>>> >>>>> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig >>>>> index 711f82400086..6ff3921d7a62 100644 >>>>> --- a/drivers/perf/Kconfig >>>>> +++ b/drivers/perf/Kconfig >>>>> @@ -209,6 +209,13 @@ 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 && PCI) >>>>> + help >>>>> + Enable perf support for Synopsys DesignWare PCIe PMU Performance >>>>> + monitoring event on Yitian 710 platform. >>> >>> The documentation kind of implies this isn't platform specific. >>> If some parts are (such as which events exist) then you may want to push >>> that to userspace / perftool with appropriate matching against specific SoC. >>> >>> If it is generic, then change this text to "event on platform including the Yitian 710." >> >> It is generic without any platform specific, so I will change it as you expected. >> >>> >>>>> + >>>>> source "drivers/perf/arm_cspmu/Kconfig" >>>>> >>>>> source "drivers/perf/amlogic/Kconfig" >>> >>>>> new file mode 100644 >>>>> index 000000000000..8bfcf6e0662d >>>>> --- /dev/null >>>>> +++ b/drivers/perf/dwc_pcie_pmu.c >>>>> @@ -0,0 +1,706 @@ >>> >>> ... >>> >>>>> + >>>>> +struct dwc_pcie_pmu { >>>>> + struct pci_dev *pdev; /* Root Port device */ >>>> >>>> If the root port removed after the probe of this PCIe PMU driver, we'll access the NULL >>>> pointer. I didn't see you hold the root port to avoid the removal. >> >> Do you mean that I should have a reference count of rootport by pci_dev_get() when allocating >> pcie_pmu? >> >> pcie_pmu->pdev = pci_dev_get(); > > It could be one option, but will block the removal of device from userspace. Another option > is to register a PCI bus notifier then on removal/added the driver can get notified and handle > it, for example, remove the related PMU on the removal of the root ports. I see, but can root port be removed from userspace? I check the hotplug slot interface, no root port is available to power off. Thank you. Best Regards, Shuai
