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
