RE: [PATCH v2 net-next 4/5] stmmac: intel: add support for multi-vector msi and msi-x

[Ong, Boon Leong]

>+static int stmmac_config_multi_msi(struct pci_dev *pdev,
>+                                 struct plat_stmmacenet_data *plat,
>+                                 struct stmmac_resources *res)
>+{
For optimum RX & TX queue processing on the same IRQ, we should use
irq_set_affinity_hint() to set those RXQ and TXQ IRQ to the same CPU.
This will benefit processing for up-coming XDP TX and XDP TX ZC processing.

cpumask_t cpu_mask;

>+      int ret;
>+      int i;
>+
>+      if (plat->msi_rx_base_vec >= STMMAC_MSI_VEC_MAX ||
>+          plat->msi_tx_base_vec >= STMMAC_MSI_VEC_MAX) {
>+              dev_info(&pdev->dev, "%s: Invalid RX & TX vector defined\n",
>+                       __func__);
>+              return -1;
>+      }
>+
>+      ret = pci_alloc_irq_vectors(pdev, 2, STMMAC_MSI_VEC_MAX,
>+                                  PCI_IRQ_MSI | PCI_IRQ_MSIX);
>+      if (ret < 0) {
>+              dev_info(&pdev->dev, "%s: multi MSI enablement failed\n",
>+                       __func__);
>+              return ret;
>+      }
>+
>+      /* For RX MSI */
>+      for (i = 0; i < plat->rx_queues_to_use; i++) {
>+              res->rx_irq[i] = pci_irq_vector(pdev,
>+                                              plat->msi_rx_base_vec + i * 2);

                cpumask_clear(&cpu_mask);
                cpumask_set_cpu(i % num_online_cpus(), &cpu_mask);
                irq_set_affinity_hint(res->rx_irq[i], &cpu_mask);

>+      }
>+
>+      /* For TX MSI */
>+      for (i = 0; i < plat->tx_queues_to_use; i++) {
>+              res->tx_irq[i] = pci_irq_vector(pdev,
>+                                              plat->msi_tx_base_vec + i * 2);

                cpumask_clear(&cpu_mask);
                cpumask_set_cpu(i % num_online_cpus(), &cpu_mask);
                irq_set_affinity_hint(res->tx_irq[i], &cpu_mask);

>+      }
>+
>+      if (plat->msi_mac_vec < STMMAC_MSI_VEC_MAX)
>+              res->irq = pci_irq_vector(pdev, plat->msi_mac_vec);
>+      if (plat->msi_wol_vec < STMMAC_MSI_VEC_MAX)
>+              res->wol_irq = pci_irq_vector(pdev, plat->msi_wol_vec);
>+      if (plat->msi_lpi_vec < STMMAC_MSI_VEC_MAX)
>+              res->lpi_irq = pci_irq_vector(pdev, plat->msi_lpi_vec);
>+      if (plat->msi_sfty_ce_vec < STMMAC_MSI_VEC_MAX)
>+              res->sfty_ce_irq = pci_irq_vector(pdev, plat-
>>msi_sfty_ce_vec);
>+      if (plat->msi_sfty_ue_vec < STMMAC_MSI_VEC_MAX)
>+              res->sfty_ue_irq = pci_irq_vector(pdev, plat-
>>msi_sfty_ue_vec);
>+
>+      plat->multi_msi_en = 1;
>+      dev_info(&pdev->dev, "%s: multi MSI enablement successful\n",
>__func__);
>+
>+      return 0;
>+}