PCI: iproc: Implement MSI controller node detection with of_msi_xlate()

The functionality implemented in the iproc driver in order to detect an
OF MSI controller node is now fully implemented in of_msi_xlate().

Replace the current msi-map/msi-parent parsing code with of_msi_xlate().

Since of_msi_xlate() is also a deviceID mapping API, pass in a fictitious
0 as deviceID - the driver only requires detecting the OF MSI controller
node not the deviceID mapping per-se (of_msi_xlate() return value is
ignored for the same reason).

Signed-off-by: Lorenzo Pieralisi <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Reviewed-by: Frank Li <[e-mail]>
Acked-by: Bjorn Helgaas <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

drivers/pci/controller/pcie-iproc.c

···
 #include <linux/irqchip/arm-gic-v3.h>
 #include <linux/platform_device.h>
 #include <linux/of_address.h>
+#include <linux/of_irq.h>
 #include <linux/of_pci.h>
 #include <linux/of_platform.h>
 #include <linux/phy/phy.h>
···
 
 static int iproc_pcie_msi_enable(struct iproc_pcie *pcie)
 {
-	struct device_node *msi_node;
+	struct device_node *msi_node = NULL;
 	int ret;
 
 	/*
 	 * Either the "msi-parent" or the "msi-map" phandle needs to exist
 	 * for us to obtain the MSI node.
 	 */
-
-	msi_node = of_parse_phandle(pcie->dev->of_node, "msi-parent", 0);
-	if (!msi_node) {
-		const __be32 *msi_map = NULL;
-		int len;
-		u32 phandle;
-
-		msi_map = of_get_property(pcie->dev->of_node, "msi-map", &len);
-		if (!msi_map)
-			return -ENODEV;
-
-		phandle = be32_to_cpup(msi_map + 1);
-		msi_node = of_find_node_by_phandle(phandle);
-		if (!msi_node)
-			return -ENODEV;
-	}
+	of_msi_xlate(pcie->dev, &msi_node, 0);
+	if (!msi_node)
+		return -ENODEV;
 
 	/*
 	 * Certain revisions of the iProc PCIe controller require additional