[PATCH 02/10] PCI/MSI: Introduce weak pcibios_msi_controller()

[Yijing Wang <wangyijing@huawei.com>]

Introduce a new weak pcibios_msi_controller() to
get the associate msi_chip for PCI bus. This is
preparation for save msi_chip in arch PCI sysdata.
This weak function will be removed after we save
msi_chip in generic pci_host_bridge.

Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
---
 drivers/pci/msi.c |   19 +++++++++++++++++--
 1 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 1c7ca4a..f085f7f 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -30,9 +30,24 @@ int pci_msi_ignore_mask;
 
 /* Arch hooks */
 
+struct msi_controller * __weak pcibios_msi_controller(struct pci_bus *bus)
+{
+	return NULL;
+}
+
+struct msi_controller *pci_msi_controller(struct pci_bus *bus)
+{
+	struct msi_controller *ctrl = bus->msi;
+
+	if (ctrl)
+		return ctrl;
+
+	return pcibios_msi_controller(bus);
+}
+
 int __weak arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
 {
-	struct msi_controller *ctrl = dev->bus->msi;
+	struct msi_controller *ctrl = pci_msi_controller(dev->bus);
 	int err;
 
 	if (!ctrl || !ctrl->setup_irq)
@@ -48,7 +63,7 @@ int __weak arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
 void __weak arch_teardown_msi_irq(unsigned int irq)
 {
 	struct msi_desc *entry = irq_get_msi_desc(irq);
-	struct msi_controller *ctrl = entry->dev->bus->msi;
+	struct msi_controller *ctrl = pci_msi_controller(entry->dev->bus);
 
 	if (!ctrl || !ctrl->teardown_irq)
 		return;
-- 
1.7.1