[RFC 13/15] PCI: turn pcibios_alloc_irq into a callback

[Arnd Bergmann <arnd@xxxxxxxx>]

Weak functions are a bit confusing, and we can better deal with
this using a callback function. pcibios_free_irq() is actually
completely unused, but it seems better to treat it the same way
as the allocation, unless we want to remove it completely.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 arch/arm64/kernel/pci.c  | 16 +++-------------
 drivers/pci/pci-driver.c | 13 +++++++++++--
 include/linux/pci.h      |  2 ++
 3 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c
index 0e2ea1c78542..3d196c68e362 100644
--- a/arch/arm64/kernel/pci.c
+++ b/arch/arm64/kernel/pci.c
@@ -22,19 +22,6 @@
 #include <linux/pci-ecam.h>
 #include <linux/slab.h>
 
-#ifdef CONFIG_ACPI
-/*
- * Try to assign the IRQ number when probing a new device
- */
-int pcibios_alloc_irq(struct pci_dev *dev)
-{
-	if (!acpi_disabled)
-		acpi_pci_irq_enable(dev);
-
-	return 0;
-}
-#endif
-
 /*
  * raw_pci_read/write - Platform-specific PCI config space access.
  */
@@ -93,6 +80,9 @@ int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge)
 
 		ACPI_COMPANION_SET(&bridge->dev, adev);
 		set_dev_node(bus_dev, acpi_get_node(acpi_device_handle(adev)));
+
+		/* Try to assign the IRQ number when probing a new device */
+		bridge->alloc_irq = acpi_pci_irq_enable;
 	}
 
 	return 0;
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index bef17c3fca67..c96bc7bd56da 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -387,13 +387,22 @@ static int __pci_device_probe(struct pci_driver *drv, struct pci_dev *pci_dev)
 	return error;
 }
 
-int __weak pcibios_alloc_irq(struct pci_dev *dev)
+int pcibios_alloc_irq(struct pci_dev *dev)
 {
+	struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);
+
+	if (bridge->alloc_irq)
+		return bridge->alloc_irq(dev);
+
 	return 0;
 }
 
-void __weak pcibios_free_irq(struct pci_dev *dev)
+void pcibios_free_irq(struct pci_dev *dev)
 {
+	struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);
+
+	if (bridge->free_irq)
+		bridge->free_irq(dev);
 }
 
 #ifdef CONFIG_PCI_IOV
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d1072690cb4f..1296d9fcc5da 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -476,6 +476,8 @@ struct pci_host_bridge {
 	int (*map_irq)(const struct pci_dev *, u8, u8);
 	void (*release_fn)(struct pci_host_bridge *);
 	void (*bus_add_device)(struct pci_dev *pdev);
+	int (*alloc_irq)(struct pci_dev *);
+	int (*free_irq)(struct pci_dev *);
 	void		*release_data;
 	struct msi_controller *msi;
 	unsigned int	ignore_reset_delay:1;	/* For entire hierarchy */
-- 
2.18.0