genirq/MSI: Move alloc_msi_entry() from PCI into generic MSI code

Move alloc_msi_entry() from PCI MSI code into generic MSI code, so it
can be reused by other generic MSI drivers.  Also introduce
free_msi_entry() for completeness.

Suggested-by: Stuart Yoder <stuart.yoder@freescale.com>.
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Yijing Wang <wangyijing@huawei.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Alexander Gordeev <agordeev@redhat.com>
Link: http://lkml.kernel.org/r/1436428847-8886-13-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/pci/msi.c

@@ -406,18 +406,6 @@ static void free_msi_irqs(struct pci_dev *dev)
 	}
 }
 
-static struct msi_desc *alloc_msi_entry(struct pci_dev *dev)
-{
-	struct msi_desc *desc = kzalloc(sizeof(*desc), GFP_KERNEL);
-	if (!desc)
-		return NULL;
-
-	INIT_LIST_HEAD(&desc->list);
-	desc->dev = &dev->dev;
-
-	return desc;
-}
-
 static void pci_intx_for_msi(struct pci_dev *dev, int enable)
 {
 	if (!(dev->dev_flags & PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG))
@@ -572,7 +560,7 @@ static struct msi_desc *msi_setup_entry(struct pci_dev *dev, int nvec)
 	struct msi_desc *entry;
 
 	/* MSI Entry Initialization */
-	entry = alloc_msi_entry(dev);
+	entry = alloc_msi_entry(&dev->dev);
 	if (!entry)
 		return NULL;
 
@@ -700,7 +688,7 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
 	int i;
 
 	for (i = 0; i < nvec; i++) {
-		entry = alloc_msi_entry(dev);
+		entry = alloc_msi_entry(&dev->dev);
 		if (!entry) {
 			if (!i)
 				iounmap(base);

include/linux/msi.h

@@ -96,6 +96,8 @@ static inline void *msi_desc_to_pci_sysdata(struct msi_desc *desc)
 }
 #endif /* CONFIG_PCI_MSI */
 
+struct msi_desc *alloc_msi_entry(struct device *dev);
+void free_msi_entry(struct msi_desc *entry);
 void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
 void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
 void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg);

kernel/irq/msi.c

@@ -18,6 +18,23 @@
 /* Temparory solution for building, will be removed later */
 #include <linux/pci.h>
 
+struct msi_desc *alloc_msi_entry(struct device *dev)
+{
+	struct msi_desc *desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return NULL;
+
+	INIT_LIST_HEAD(&desc->list);
+	desc->dev = dev;
+
+	return desc;
+}
+
+void free_msi_entry(struct msi_desc *entry)
+{
+	kfree(entry);
+}
+
 void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 {
 	*msg = entry->msg;