PCI/MSI: Move MSI/MSI-X init to msi.c

Move pci_msi_setup_pci_dev(), which disables MSI and MSI-X interrupts, from
probe.c to msi.c so it's with all the other MSI code and more consistent
with other capability initialization.  This means we must compile msi.c
always, even without CONFIG_PCI_MSI, so wrap the rest of msi.c in an #ifdef
and adjust the Makefile accordingly.  No functional change intended.

Link: https://lore.kernel.org/r/20201203185110.1583077-2-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>

drivers/pci/Makefile

@@ -5,7 +5,7 @@
 obj-$(CONFIG_PCI)		+= access.o bus.o probe.o host-bridge.o \
 				   remove.o pci.o pci-driver.o search.o \
 				   pci-sysfs.o rom.o setup-res.o irq.o vpd.o \
-				   setup-bus.o vc.o mmap.o setup-irq.o
+				   setup-bus.o vc.o mmap.o setup-irq.o msi.o
 
 obj-$(CONFIG_PCI)		+= pcie/
 
@@ -18,7 +18,6 @@ endif
 obj-$(CONFIG_OF)		+= of.o
 obj-$(CONFIG_PCI_QUIRKS)	+= quirks.o
 obj-$(CONFIG_HOTPLUG_PCI)	+= hotplug/
-obj-$(CONFIG_PCI_MSI)		+= msi.o
 obj-$(CONFIG_PCI_ATS)		+= ats.o
 obj-$(CONFIG_PCI_IOV)		+= iov.o
 obj-$(CONFIG_PCI_BRIDGE_EMUL)	+= pci-bridge-emul.o

drivers/pci/msi.c

@@ -26,6 +26,8 @@
 
 #include "pci.h"
 
+#ifdef CONFIG_PCI_MSI
+
 static int pci_msi_enable = 1;
 int pci_msi_ignore_mask;
 
@@ -1577,3 +1579,37 @@ 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);
+}
+
+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/pci.h

@@ -104,6 +104,8 @@ void pci_config_pm_runtime_get(struct pci_dev *dev);
 void pci_config_pm_runtime_put(struct pci_dev *dev);
 void pci_pm_init(struct pci_dev *dev);
 void pci_ea_init(struct pci_dev *dev);
+void pci_msi_init(struct pci_dev *dev);
+void pci_msix_init(struct pci_dev *dev);
 void pci_allocate_cap_save_buffers(struct pci_dev *dev);
 void pci_free_cap_save_buffers(struct pci_dev *dev);
 bool pci_bridge_d3_possible(struct pci_dev *dev);

drivers/pci/probe.c

@@ -1716,22 +1716,6 @@ static u8 pci_hdr_type(struct pci_dev *dev)
 
 #define LEGACY_IO_RESOURCE	(IORESOURCE_IO | IORESOURCE_PCI_FIXED)
 
-static void pci_msi_setup_pci_dev(struct pci_dev *dev)
-{
-	/*
-	 * 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)
-		pci_msi_set_enable(dev, 0);
-
-	dev->msix_cap = pci_find_capability(dev, PCI_CAP_ID_MSIX);
-	if (dev->msix_cap)
-		pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
-}
-
 /**
  * pci_intx_mask_broken - Test PCI_COMMAND_INTX_DISABLE writability
  * @dev: PCI device
@@ -2397,9 +2381,8 @@ void pcie_report_downtraining(struct pci_dev *dev)
 static void pci_init_capabilities(struct pci_dev *dev)
 {
 	pci_ea_init(dev);		/* Enhanced Allocation */
-
-	/* Setup MSI caps & disable MSI/MSI-X interrupts */
-	pci_msi_setup_pci_dev(dev);
+	pci_msi_init(dev);		/* Disable MSI */
+	pci_msix_init(dev);		/* Disable MSI-X */
 
 	/* Buffers for saving PCIe and PCI-X capabilities */
 	pci_allocate_cap_save_buffers(dev);