[patch V2 06/40] PCI/MSI: Provide static key for parent mask/unmask

[Thomas Gleixner]

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 static key which lets the domain implementation enable this
sequence in the PCI/MSI code.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
 drivers/pci/msi/irqdomain.c |   30 ++++++++++++++++++++++++++++++
 include/linux/msi.h         |    2 ++
 2 files changed, 32 insertions(+)

--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -148,17 +148,45 @@ static void pci_device_domain_set_desc(m
 	arg->hwirq = desc->msi_index;
 }
 
+static DEFINE_STATIC_KEY_FALSE(pci_msi_mask_unmask_parent);
+
+/**
+ * pci_device_msi_mask_unmask_parent_enable - Enable propagation of mask/unmask
+ *					      to the parent interrupt chip
+ *
+ * For MSI parent interrupt domains which want to mask at the parent interrupt
+ * chip too.
+ */
+void pci_device_msi_mask_unmask_parent_enable(void)
+{
+	static_branch_enable(&pci_msi_mask_unmask_parent);
+}
+
+static __always_inline void cond_mask_parent(struct irq_data *data)
+{
+	if (static_branch_unlikely(&pci_msi_mask_unmask_parent))
+		irq_chip_mask_parent(data);
+}
+
+static __always_inline void cond_unmask_parent(struct irq_data *data)
+{
+	if (static_branch_unlikely(&pci_msi_mask_unmask_parent))
+		irq_chip_unmask_parent(data);
+}
+
 static void pci_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_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 +223,12 @@ static struct msi_domain_template pci_ms
 static void pci_mask_msix(struct irq_data *data)
 {
 	pci_msix_mask(irq_data_get_msi_desc(data));
+	cond_mask_parent(data);
 }
 
 static void pci_unmask_msix(struct irq_data *data)
 {
+	cond_unmask_parent(data);
 	pci_msix_unmask(irq_data_get_msi_desc(data));
 }
 
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -653,12 +653,14 @@ struct irq_domain *pci_msi_create_irq_do
 					     struct irq_domain *parent);
 u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev);
 struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev);
+void pci_device_msi_mask_unmask_parent_enable(void);
 #else /* CONFIG_PCI_MSI */
 static inline struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
 {
 	return NULL;
 }
 static inline void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg) { }
+static inline void pci_device_msi_mask_unmask_parent_enable(void) { }
 #endif /* !CONFIG_PCI_MSI */
 
 #endif /* LINUX_MSI_H */