PCI/MSI: Split out CONFIG_PCI_MSI independent part

These functions are required even when CONFIG_PCI_MSI is not set. Move them
to their own file.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211206210224.710137730@linutronix.de

drivers/pci/msi/Makefile

 # SPDX-License-Identifier: GPL-2.0
 #
 # Makefile for the PCI/MSI
-obj-$(CONFIG_PCI)		+= msi.o
+obj-$(CONFIG_PCI)		+= pcidev_msi.o
+obj-$(CONFIG_PCI_MSI)		+= msi.o

drivers/pci/msi/msi.c

@@ -18,8 +18,6 @@
 
 #include "../pci.h"
 
-#ifdef CONFIG_PCI_MSI
-
 static int pci_msi_enable = 1;
 int pci_msi_ignore_mask;
 
@@ -1493,40 +1491,3 @@ bool pci_dev_has_special_msi_domain(struct pci_dev *pdev)
 }
 
 #endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
-#endif /* CONFIG_PCI_MSI */
-
-void pci_msi_init(struct pci_dev *dev)
-{
-	u16 ctrl;
-
-	/*
-	 * Disable the MSI hardware to avoid screaming interrupts
-	 * during boot.  This is the power on reset default so
-	 * usually this should be a noop.
-	 */
-	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
-	if (!dev->msi_cap)
-		return;
-
-	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &ctrl);
-	if (ctrl & PCI_MSI_FLAGS_ENABLE)
-		pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS,
-				      ctrl & ~PCI_MSI_FLAGS_ENABLE);
-
-	if (!(ctrl & PCI_MSI_FLAGS_64BIT))
-		dev->no_64bit_msi = 1;
-}
-
-void pci_msix_init(struct pci_dev *dev)
-{
-	u16 ctrl;
-
-	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
-	if (!dev->msix_cap)
-		return;
-
-	pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &ctrl);
-	if (ctrl & PCI_MSIX_FLAGS_ENABLE)
-		pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS,
-				      ctrl & ~PCI_MSIX_FLAGS_ENABLE);
-}

drivers/pci/msi/pcidev_msi.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MSI[X} related functions which are available unconditionally.
+ */
+#include "../pci.h"
+
+/*
+ * Disable the MSI[X] hardware to avoid screaming interrupts during boot.
+ * This is the power on reset default so usually this should be a noop.
+ */
+
+void pci_msi_init(struct pci_dev *dev)
+{
+	u16 ctrl;
+
+	dev->msi_cap = pci_find_capability(dev, PCI_CAP_ID_MSI);
+	if (!dev->msi_cap)
+		return;
+
+	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &ctrl);
+	if (ctrl & PCI_MSI_FLAGS_ENABLE) {
+		pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS,
+				      ctrl & ~PCI_MSI_FLAGS_ENABLE);
+	}
+
+	if (!(ctrl & PCI_MSI_FLAGS_64BIT))
+		dev->no_64bit_msi = 1;
+}
+
+void pci_msix_init(struct pci_dev *dev)
+{
+	u16 ctrl;
+
+	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
+	if (!dev->msix_cap)
+		return;
+
+	pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &ctrl);
+	if (ctrl & PCI_MSIX_FLAGS_ENABLE) {
+		pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS,
+				      ctrl & ~PCI_MSIX_FLAGS_ENABLE);
+	}
+}