PCI/MSI: Move pci_msi_restore_state() to api.c

To disentangle the maze in msi.c, all exported device-driver MSI APIs are
now to be grouped in one file, api.c.
    
Move pci_msi_enabled() and add kernel-doc for the function.
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20221111122015.331584998@linutronix.de

drivers/pci/msi/api.c

@@ -308,6 +308,21 @@ void pci_free_irq_vectors(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_free_irq_vectors);
 
+/**
+ * pci_restore_msi_state() - Restore cached MSI(-X) state on device
+ * @dev: the PCI device to operate on
+ *
+ * Write the Linux-cached MSI(-X) state back on device. This is
+ * typically useful upon system resume, or after an error-recovery PCI
+ * adapter reset.
+ */
+void pci_restore_msi_state(struct pci_dev *dev)
+{
+	__pci_restore_msi_state(dev);
+	__pci_restore_msix_state(dev);
+}
+EXPORT_SYMBOL_GPL(pci_restore_msi_state);
+
 /**
  * pci_msi_enabled() - Are MSI(-X) interrupts enabled system-wide?
  *

drivers/pci/msi/msi.c

@@ -199,7 +199,7 @@ bool __weak arch_restore_msi_irqs(struct pci_dev *dev)
 	return true;
 }
 
-static void __pci_restore_msi_state(struct pci_dev *dev)
+void __pci_restore_msi_state(struct pci_dev *dev)
 {
 	struct msi_desc *entry;
 	u16 control;
@@ -231,7 +231,7 @@ static void pci_msix_clear_and_set_ctrl(struct pci_dev *dev, u16 clear, u16 set)
 	pci_write_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, ctrl);
 }
 
-static void __pci_restore_msix_state(struct pci_dev *dev)
+void __pci_restore_msix_state(struct pci_dev *dev)
 {
 	struct msi_desc *entry;
 	bool write_msg;
@@ -257,13 +257,6 @@ static void __pci_restore_msix_state(struct pci_dev *dev)
 	pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
 }
 
-void pci_restore_msi_state(struct pci_dev *dev)
-{
-	__pci_restore_msi_state(dev);
-	__pci_restore_msix_state(dev);
-}
-EXPORT_SYMBOL_GPL(pci_restore_msi_state);
-
 static void pcim_msi_release(void *pcidev)
 {
 	struct pci_dev *dev = pcidev;

drivers/pci/msi/msi.h

@@ -94,6 +94,8 @@ void pci_free_msi_irqs(struct pci_dev *dev);
 int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec, struct irq_affinity *affd);
 int __pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, int minvec,
 			    int maxvec,  struct irq_affinity *affd, int flags);
+void __pci_restore_msi_state(struct pci_dev *dev);
+void __pci_restore_msix_state(struct pci_dev *dev);
 
 /* Legacy (!IRQDOMAIN) fallbacks */