s390/pci: PCI adapter interrupts for MSI/MSI-X

Support PCI adapter interrupts using the Single-IRQ-mode. Single-IRQ-mode
disables an adapter IRQ automatically after delivering it until the SIC
instruction enables it again. This is used to reduce the number of IRQs
for streaming workloads.

Up to 64 MSI handlers can be registered per PCI function.
A hash table is used to map interrupt numbers to MSI descriptors.
The interrupt vector is scanned using the flogr instruction.
Only MSI/MSI-X interrupts are supported, no legacy INTs.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/pci/msi.c

@@ -207,6 +207,8 @@ static void msix_mask_irq(struct msi_desc *desc, u32 flag)
 	desc->masked = __msix_mask_irq(desc, flag);
 }
 
+#ifdef CONFIG_GENERIC_HARDIRQS
+
 static void msi_set_mask_bit(struct irq_data *data, u32 flag)
 {
 	struct msi_desc *desc = irq_data_get_msi(data);
@@ -230,6 +232,8 @@ void unmask_msi_irq(struct irq_data *data)
 	msi_set_mask_bit(data, 0);
 }
 
+#endif /* CONFIG_GENERIC_HARDIRQS */
+
 void __read_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 {
 	BUG_ON(entry->dev->current_state != PCI_D0);
@@ -337,8 +341,10 @@ static void free_msi_irqs(struct pci_dev *dev)
 		if (!entry->irq)
 			continue;
 		nvec = 1 << entry->msi_attrib.multiple;
+#ifdef CONFIG_GENERIC_HARDIRQS
 		for (i = 0; i < nvec; i++)
 			BUG_ON(irq_has_action(entry->irq + i));
+#endif
 	}
 
 	arch_teardown_msi_irqs(dev);