PCI/MSI: Initialize MSI capability for all architectures

1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel doesn't
support MSI") moved dev->msi_cap and dev->msix_cap initialization from the
pci_init_capabilities() path (used on all architectures) to the
pci_setup_device() path (not used on Open Firmware architectures).

This broke MSI or MSI-X on Open Firmware machines.  4d9aac397a5d
("powerpc/PCI: Disable MSI/MSI-X interrupts at PCI probe time in OF case")
fixed it for PowerPC but not for SPARC.

Set up MSI and MSI-X (initialize msi_cap and msix_cap and disable MSI and
MSI-X) in pci_init_capabilities() so all architectures do it the same way.

This reverts 4d9aac397a5d since this patch fixes the problem generically
for both PowerPC and SPARC.

[bhelgaas: changelog, make pci_msi_setup_pci_dev() static]
Fixes: 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel doesn't support MSI")
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

arch/powerpc/kernel/pci_of_scan.c

@@ -187,9 +187,6 @@ struct pci_dev *of_create_pci_dev(struct device_node *node,
 
 	pci_device_add(dev, bus);
 
-	/* Setup MSI caps & disable MSI/MSI-X interrupts */
-	pci_msi_setup_pci_dev(dev);
-
 	return dev;
 }
 EXPORT_SYMBOL(of_create_pci_dev);

drivers/pci/probe.c

@@ -1145,7 +1145,7 @@ int pci_cfg_space_size(struct pci_dev *dev)
 
 #define LEGACY_IO_RESOURCE	(IORESOURCE_IO | IORESOURCE_PCI_FIXED)
 
-void pci_msi_setup_pci_dev(struct pci_dev *dev)
+static void pci_msi_setup_pci_dev(struct pci_dev *dev)
 {
 	/*
 	 * Disable the MSI hardware to avoid screaming interrupts
@@ -1212,8 +1212,6 @@ int pci_setup_device(struct pci_dev *dev)
 	/* "Unknown power state" */
 	dev->current_state = PCI_UNKNOWN;
 
-	pci_msi_setup_pci_dev(dev);
-
 	/* Early fixups, before probing the BARs */
 	pci_fixup_device(pci_fixup_early, dev);
 	/* device class may be changed after fixup */
@@ -1606,6 +1604,9 @@ static void pci_init_capabilities(struct pci_dev *dev)
 	/* MSI/MSI-X list */
 	pci_msi_init_pci_dev(dev);
 
+	/* Setup MSI caps & disable MSI/MSI-X interrupts */
+	pci_msi_setup_pci_dev(dev);
+
 	/* Buffers for saving PCIe and PCI-X capabilities */
 	pci_allocate_cap_save_buffers(dev);
 

include/linux/pci.h

@@ -1248,8 +1248,6 @@ struct msix_entry {
 	u16	entry;	/* driver uses to specify entry, OS writes */
 };
 
-void pci_msi_setup_pci_dev(struct pci_dev *dev);
-
 #ifdef CONFIG_PCI_MSI
 int pci_msi_vec_count(struct pci_dev *dev);
 void pci_msi_shutdown(struct pci_dev *dev);