cnss2: Set irq vector affinity to CPU0 with VT-d disabled

With VT-d disabled on x86 platform, only one pci irq vector is allocated.
Due to the irq is not freed when suspend, the kernel will migrate irq to
CPU0 if it was affine to other CPU and then allocate a new MSI vector,
which cause the issue about no irq handler for vector once resume since
the driver only configure MSI data once during driver loading.

The fix is to set irq vector affinity to CPU0 before calling request_irq
to avoid the irq migration.

Change-Id: Id366e33113089f50899eb3631db66dcde0999d84
CRs-Fixed: 3550165

cnss2/pci.c

@@ -5212,6 +5212,19 @@ int cnss_pci_get_user_msi_assignment(struct cnss_pci_data *pci_priv,
 					    base_vector);
 }
 
+static int cnss_pci_irq_set_affinity_hint(struct cnss_pci_data *pci_priv,
+					  unsigned int vec,
+					  const struct cpumask *cpumask)
+{
+	int ret;
+	struct pci_dev *pci_dev = pci_priv->pci_dev;
+
+	ret = irq_set_affinity_hint(pci_irq_vector(pci_dev, vec),
+				    cpumask);
+
+	return ret;
+}
+
 static int cnss_pci_enable_msi(struct cnss_pci_data *pci_priv)
 {
 	int ret = 0;
@@ -5253,6 +5266,24 @@ static int cnss_pci_enable_msi(struct cnss_pci_data *pci_priv)
 		goto reset_msi_config;
 	}
 
+	/* With VT-d disabled on x86 platform, only one pci irq vector is
+	 * allocated. Once suspend the irq may be migrated to CPU0 if it was
+	 * affine to other CPU with one new msi vector re-allocated.
+	 * The observation cause the issue about no irq handler for vector
+	 * once resume.
+	 * The fix is to set irq vector affinity to CPU0 before calling
+	 * request_irq to avoid the irq migration.
+	 */
+	if (cnss_pci_is_one_msi(pci_priv)) {
+		ret = cnss_pci_irq_set_affinity_hint(pci_priv,
+						     0,
+						     cpumask_of(0));
+		if (ret) {
+			cnss_pr_err("Failed to affinize irq vector to CPU0\n");
+			goto free_msi_vector;
+		}
+	}
+
 	if (cnss_pci_config_msi_addr(pci_priv)) {
 		ret = -EINVAL;
 		goto free_msi_vector;
@@ -5266,6 +5297,8 @@ static int cnss_pci_enable_msi(struct cnss_pci_data *pci_priv)
 	return 0;
 
 free_msi_vector:
+	if (cnss_pci_is_one_msi(pci_priv))
+		cnss_pci_irq_set_affinity_hint(pci_priv, 0, NULL);
 	pci_free_irq_vectors(pci_priv->pci_dev);
 reset_msi_config:
 	pci_priv->msi_config = NULL;
@@ -5278,6 +5311,9 @@ static void cnss_pci_disable_msi(struct cnss_pci_data *pci_priv)
 	if (pci_priv->device_id == QCA6174_DEVICE_ID)
 		return;
 
+	if (cnss_pci_is_one_msi(pci_priv))
+		cnss_pci_irq_set_affinity_hint(pci_priv, 0, NULL);
+
 	pci_free_irq_vectors(pci_priv->pci_dev);
 }