[PATCH] Enable MSI/MSI-X caps and disable MSI interrupts at PCI probe time - code move

[Guilherme G. Piccoli]

Commit 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel
doesn't support MSI") changed the location of the code that initializes
dev->msi_cap/msix_cap and disables MSI/MSI-X interrupts at PCI probe
time in devices that have this flag set. It moved the code from
pci_msi_init_pci_dev() to a new function named pci_msi_setup_pci_dev(),
called by pci_setup_device().

In Open Firmware code path (PowerPC pSeries/SPARC archs) the function
pci_setup_device() is not called, so MSI capabilities are never enabled,
leading to error messages as:

	bnx2x 0000:01:00.0: no msix capability found

Commit 4d9aac397a5d ("powerpc/PCI: Disable MSI/MSI-X interrupts at PCI
probe time in OF case") solved the issue on PowerPC pSeries arch calling
manually pci_msi_setup_pci_dev() on appropriate place. However, this
modification does not solve the general case (SPARC arch should be
modified too) and duplicates a lot of code, as pointed by Bjorn Helgaas.
As suggested by him, worth to reorganize the code to generally solve the
MSI caps issue and avoid too much code duplication.

This patch does exactly this: we remove both the pci_msi_setup_pci_dev()
call from pci_setup_device() and the same call in OF code path of PowerPC
pSeries arch. Then, we call pci_msi_setup_pci_dev() directly from
pci_init_capabilities(). So, we can initialize MSI caps and disable MSI
interruptions during PCI probe in general fashion, avoiding code
duplication.

Notice that this patch has the same practical effect of reverting
commit 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel
doesn't support MSI") and commit 4d9aac397a5d ("powerpc/PCI: Disable
MSI/MSI-X interrupts at PCI probe time in OF case"). Regarding the
former, the author called pci_msi_setup_pci_dev() from pci_setup_device()
because there was an early quirk used in pci_msi_off(), which depended on
pci_msi_setup_pci_dev(). Since pci_msi_off() was completely removed by
commit c6201cd8513d ("PCI/MSI: Remove unused pci_msi_off()"), we can call
pci_msi_setup_pci_dev() directly from pci_init_capabilities().

Signed-off-by: Guilherme G. Piccoli <gpiccoli at linux.vnet.ibm.com>
---
 arch/powerpc/kernel/pci_of_scan.c | 3 ---
 drivers/pci/probe.c               | 5 +++--
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/pci_of_scan.c b/arch/powerpc/kernel/pci_of_scan.c
index 2e710c1..526ac67 100644
--- a/arch/powerpc/kernel/pci_of_scan.c
+++ b/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);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8361d27..0aac86e 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1209,8 +1209,6 @@ 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 */
@@ -1600,6 +1598,9 @@ 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);
 
-- 
2.1.0