PCI/MSI: Provide MSI_FLAG_PCI_MSI_MASK_PARENT

Most ARM(64) PCI/MSI domains mask and unmask in the parent domain after or
before the PCI mask/unmask operation takes place. So there are more than a
dozen of the same wrapper implementation all over the place.

Don't make the same mistake with the new per device PCI/MSI domains and
provide a new MSI feature flag, which lets the domain implementation
enable this sequence in the PCI/MSI code.

Signed-off-by: Shivamurthy Shastri <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
Link: https://lore.kernel.org/r/87ed8j34pj.ffs@tglx

Author: shivamurthyshastri

drivers/pci/msi/irqdomain.c

@@ -148,17 +148,35 @@ static void pci_device_domain_set_desc(msi_alloc_info_t *arg, struct msi_desc *d
 	arg->hwirq = desc->msi_index;
 }
 
+static __always_inline void cond_mask_parent(struct irq_data *data)
+{
+	struct msi_domain_info *info = data->domain->host_data;
+
+	if (unlikely(info->flags & MSI_FLAG_PCI_MSI_MASK_PARENT))
+		irq_chip_mask_parent(data);
+}
+
+static __always_inline void cond_unmask_parent(struct irq_data *data)
+{
+	struct msi_domain_info *info = data->domain->host_data;
+
+	if (unlikely(info->flags & MSI_FLAG_PCI_MSI_MASK_PARENT))
+		irq_chip_unmask_parent(data);
+}
+
 static void pci_irq_mask_msi(struct irq_data *data)
 {
 	struct msi_desc *desc = irq_data_get_msi_desc(data);
 
 	pci_msi_mask(desc, BIT(data->irq - desc->irq));
+	cond_mask_parent(data);
 }
 
 static void pci_irq_unmask_msi(struct irq_data *data)
 {
 	struct msi_desc *desc = irq_data_get_msi_desc(data);
 
+	cond_unmask_parent(data);
 	pci_msi_unmask(desc, BIT(data->irq - desc->irq));
 }
 
@@ -195,10 +213,12 @@ static const struct msi_domain_template pci_msi_template = {
 static void pci_irq_mask_msix(struct irq_data *data)
 {
 	pci_msix_mask(irq_data_get_msi_desc(data));
+	cond_mask_parent(data);
 }
 
 static void pci_irq_unmask_msix(struct irq_data *data)
 {
+	cond_unmask_parent(data);
 	pci_msix_unmask(irq_data_get_msi_desc(data));
 }
 

include/linux/msi.h

@@ -556,6 +556,8 @@ enum {
 	MSI_FLAG_USE_DEV_FWNODE		= (1 << 7),
 	/* Set parent->dev into domain->pm_dev on device domain creation */
 	MSI_FLAG_PARENT_PM_DEV		= (1 << 8),
+	/* Support for parent mask/unmask */
+	MSI_FLAG_PCI_MSI_MASK_PARENT	= (1 << 9),
 
 	/* Mask for the generic functionality */
 	MSI_GENERIC_FLAGS_MASK		= GENMASK(15, 0),