[PATCH] PCI: iproc: fix msi driver selection

[Arnd Bergmann <arnd@arndb.de>]

The newly added MSI support for iproc causes a link error when its
Kconfig option is disabled:

ERROR: "iproc_msi_exit" [drivers/pci/host/pcie-iproc.ko] undefined!
ERROR: "iproc_msi_init" [drivers/pci/host/pcie-iproc.ko] undefined!

This changes the header file so we use stub functions whenever
the driver is not built, even when CONFIG_MSI is enabled.

As the Kconfig logic for the driver is a bit off, I'm rectifying
that as well, by making it depend on the specific drivers that
call into the driver, and moving the option behind those instead
of before them.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 610894347cbf ("PCI: iproc: Add iProc PCIe MSI support")
---
Found on ARM randconfig builds a couple of days ago

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index 490476e172fd..d7c05894af70 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -124,15 +124,6 @@ config PCIE_IPROC
 	  iProc family of SoCs. An appropriate bus interface driver needs
 	  to be enabled to select this.
 
-config PCIE_IPROC_MSI
-	bool "Broadcom iProc PCIe MSI support"
-	depends on ARCH_BCM_IPROC && PCI_MSI
-	select PCI_MSI_IRQ_DOMAIN
-	default ARCH_BCM_IPROC
-	help
-	  Say Y here if you want to enable MSI support for Broadcom's iProc
-	  PCIe controller
-
 config PCIE_IPROC_PLATFORM
 	tristate "Broadcom iProc PCIe platform bus driver"
 	depends on ARCH_BCM_IPROC || (ARM && COMPILE_TEST)
@@ -154,6 +145,16 @@ config PCIE_IPROC_BCMA
 	  Say Y here if you want to use the Broadcom iProc PCIe controller
 	  through the BCMA bus interface
 
+config PCIE_IPROC_MSI
+	bool "Broadcom iProc PCIe MSI support"
+	depends on PCIE_IPROC_PLATFORM || PCIE_IPROC_BCMA
+	depends on PCI_MSI
+	select PCI_MSI_IRQ_DOMAIN
+	default ARCH_BCM_IPROC
+	help
+	  Say Y here if you want to enable MSI support for Broadcom's iProc
+	  PCIe controller
+
 config PCIE_ALTERA
 	bool "Altera PCIe controller"
 	depends on ARM || NIOS2
diff --git a/drivers/pci/host/pcie-iproc.h b/drivers/pci/host/pcie-iproc.h
index 6def23a7eb54..e84d93c53c7b 100644
--- a/drivers/pci/host/pcie-iproc.h
+++ b/drivers/pci/host/pcie-iproc.h
@@ -79,7 +79,7 @@ struct iproc_pcie {
 int iproc_pcie_setup(struct iproc_pcie *pcie, struct list_head *res);
 int iproc_pcie_remove(struct iproc_pcie *pcie);
 
-#ifdef CONFIG_PCI_MSI
+#ifdef CONFIG_PCIE_IPROC_MSI
 int iproc_msi_init(struct iproc_pcie *pcie, struct device_node *node);
 void iproc_msi_exit(struct iproc_pcie *pcie);
 #else