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 Thanks.
