On 2023/8/4 11:09, Shuai Xue wrote: > > > On 2023/8/4 10:28, Yicong Yang wrote: >> On 2023/8/4 9:39, Shuai Xue wrote: >>> >>> >>> 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. >>> >> >> For hotplug maybe not, but user can remove certian device through sysfs: >> >> echo 1 > /sys/bus/pci/devices/<root port>/remove >> > > Thank you, I will add a notifier for removal/added action. > > Best Regards, > Shuai Hi, Yicong, I am confused when adding a notifier by bus_register_notifier(). If I have added a action to pdev->dev to unregister pmu: ret = perf_pmu_register(&pcie_pmu->pmu, name, -1); if (ret) { pci_err(pcie_pmu->pdev, "Error %d registering PMU @%x\n", ret, bdf); goto out; } ret = devm_add_action_or_reset( &pdev->dev, dwc_pcie_pmu_unregister_pmu, &pcie_pmu->pmu); the pmu will be unregister when the port removes, so accessing the NULL pointer will never happen, right? Do we still need the bus_register_notifier()? Thank you. Best Regards, Shuai
