On 5/22/2023 11:54 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@xxxxxxxxxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Link: https://lore.kernel.org/oe-kbuild-all/202305170639.XU3djFZX-lkp@xxxxxxxxx/
---
[snip]
+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;
+
+ list_for_each_entry(pcie_pmu, &priv->pmu_nodes, pmu_node) {
+ cpuhp_state_remove_instance(dwc_pcie_pmu_hp_state,
+ &pcie_pmu->cpuhp_node);
+ perf_pmu_unregister(&pcie_pmu->pmu);
+ }
+
+ return 0;
+}
+
+static int dwc_pcie_pmu_probe(struct platform_device *pdev)
+{
+ struct dwc_pcie_pmu_priv *priv;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = &pdev->dev;
+ platform_set_drvdata(pdev, priv);
+
+ /* If one PMU registration fails, remove all. */
+ if (__dwc_pcie_pmu_probe(priv))
+ dwc_pcie_pmu_remove(pdev);
In this case, you should return error from __dwc_pcie_pmu_probe()
instead of returning 0, to release the requested resources of the PMU
deivce.
+
+ return 0;
+}
+
+static void dwc_pcie_pmu_migrate(struct dwc_pcie_pmu *pcie_pmu, unsigned int cpu)
+{
+ /* This PMU does NOT support interrupt, just migrate context. */
+ perf_pmu_migrate_context(&pcie_pmu->pmu, pcie_pmu->oncpu, cpu);
+ pcie_pmu->oncpu = cpu;
+}
+
+static int dwc_pcie_pmu_online_cpu(unsigned int cpu, struct hlist_node *cpuhp_node)
+{
+ struct dwc_pcie_pmu *pcie_pmu;
+ struct pci_dev *pdev;
+ int node;
+
+ pcie_pmu = hlist_entry_safe(cpuhp_node, struct dwc_pcie_pmu, cpuhp_node);
+ pdev = pcie_pmu->pdev;
+ node = dev_to_node(&pdev->dev);
+
+ if (node != NUMA_NO_NODE && cpu_to_node(pcie_pmu->oncpu) != node &&
+ cpu_to_node(cpu) == node)
+ dwc_pcie_pmu_migrate(pcie_pmu, cpu);
+
+ return 0;
+}
+
+static int dwc_pcie_pmu_offline_cpu(unsigned int cpu, struct hlist_node *cpuhp_node)
+{
+ struct dwc_pcie_pmu *pcie_pmu;
+ struct pci_dev *pdev;
+ int node;
+ cpumask_t mask;
+ unsigned int target;
+
+ pcie_pmu = hlist_entry_safe(cpuhp_node, struct dwc_pcie_pmu, cpuhp_node);
+ if (cpu != pcie_pmu->oncpu)
+ return 0;
+
+ pdev = pcie_pmu->pdev;
+ node = dev_to_node(&pdev->dev);
+ if (cpumask_and(&mask, cpumask_of_node(node), cpu_online_mask) &&
+ cpumask_andnot(&mask, &mask, cpumask_of(cpu)))
+ target = cpumask_any(&mask);
+ else
+ target = cpumask_any_but(cpu_online_mask, cpu);
+ if (target < nr_cpu_ids)
+ dwc_pcie_pmu_migrate(pcie_pmu, target);
+
+ return 0;
+}
+
+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 = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
+ "perf/dwc_pcie_pmu:online",
+ dwc_pcie_pmu_online_cpu,
+ dwc_pcie_pmu_offline_cpu);
+ if (ret < 0)
+ return ret;
+
+ dwc_pcie_pmu_hp_state = ret;
+
+ ret = platform_driver_register(&dwc_pcie_pmu_driver);
+ if (ret) {
+ cpuhp_remove_multi_state(dwc_pcie_pmu_hp_state);
+ return ret;
+ }
+
+ dwc_pcie_pmu_dev = platform_device_register_simple(
+ "dwc_pcie_pmu", PLATFORM_DEVID_NONE, NULL, 0);
+ 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);
You should also call 'cpuhp_remove_multi_state()' when exiting the driver.
With above issues fixed, you can add:
Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
