PCI: Introduce new MSI chip infrastructure

The new struct msi_chip is used to associated an MSI controller with a
PCI bus. It is automatically handed down from the root to its children
during bus enumeration.

This patch provides default (weak) implementations for the architecture-
specific MSI functions (arch_setup_msi_irq(), arch_teardown_msi_irq()
and arch_msi_check_device()) which check if a PCI device's bus has an
attached MSI chip and forward the call appropriately.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Daniel Price <daniel.price@gmail.com>
Tested-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 271dfd1..090ddad 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -65,4 +65,15 @@
 void default_teardown_msi_irqs(struct pci_dev *dev);
 void default_restore_msi_irqs(struct pci_dev *dev, int irq);
 
+struct msi_chip {
+	struct module *owner;
+	struct device *dev;
+
+	int (*setup_irq)(struct msi_chip *chip, struct pci_dev *dev,
+			 struct msi_desc *desc);
+	void (*teardown_irq)(struct msi_chip *chip, unsigned int irq);
+	int (*check_device)(struct msi_chip *chip, struct pci_dev *dev,
+			    int nvec, int type);
+};
+
 #endif /* LINUX_MSI_H */
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 0fd1f15..4044e3c 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -433,6 +433,7 @@
 	struct resource busn_res;	/* bus numbers routed to this bus */
 
 	struct pci_ops	*ops;		/* configuration access functions */
+	struct msi_chip	*msi;		/* MSI controller */
 	void		*sysdata;	/* hook for sys-specific extension */
 	struct proc_dir_entry *procdir;	/* directory entry in /proc/bus/pci */