fpga: dfl: refactor cci_enumerate_feature_devs()

In preparation of looking for dfls based on a vendor specific pci
capability, move the code for the default method of finding the first
dfl at offset 0 of Bar 0 to its own function.

Acked-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Link: https://lore.kernel.org/r/20210107043714.991646-2-mdf@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fpga/dfl-pci.c

@@ -119,49 +119,20 @@ static int *cci_pci_create_irq_table(struct pci_dev *pcidev, unsigned int nvec)
 	return table;
 }
 
-/* enumerate feature devices under pci device */
-static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
+/* default method of finding dfls starting at offset 0 of bar 0 */
+static int find_dfls_by_default(struct pci_dev *pcidev,
+				struct dfl_fpga_enum_info *info)
 {
-	struct cci_drvdata *drvdata = pci_get_drvdata(pcidev);
-	int port_num, bar, i, nvec, ret = 0;
-	struct dfl_fpga_enum_info *info;
-	struct dfl_fpga_cdev *cdev;
+	int port_num, bar, i, ret = 0;
 	resource_size_t start, len;
 	void __iomem *base;
-	int *irq_table;
 	u32 offset;
 	u64 v;
 
-	/* allocate enumeration info via pci_dev */
-	info = dfl_fpga_enum_info_alloc(&pcidev->dev);
-	if (!info)
-		return -ENOMEM;
-
-	/* add irq info for enumeration if the device support irq */
-	nvec = cci_pci_alloc_irq(pcidev);
-	if (nvec < 0) {
-		dev_err(&pcidev->dev, "Fail to alloc irq %d.\n", nvec);
-		ret = nvec;
-		goto enum_info_free_exit;
-	} else if (nvec) {
-		irq_table = cci_pci_create_irq_table(pcidev, nvec);
-		if (!irq_table) {
-			ret = -ENOMEM;
-			goto irq_free_exit;
-		}
-
-		ret = dfl_fpga_enum_info_add_irq(info, nvec, irq_table);
-		kfree(irq_table);
-		if (ret)
-			goto irq_free_exit;
-	}
-
-	/* start to find Device Feature List in Bar 0 */
+	/* start to find Device Feature List from Bar 0 */
 	base = cci_pci_ioremap_bar0(pcidev);
-	if (!base) {
-		ret = -ENOMEM;
-		goto irq_free_exit;
-	}
+	if (!base)
+		return -ENOMEM;
 
 	/*
 	 * PF device has FME and Ports/AFUs, and VF device only has one
@@ -208,12 +179,51 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
 		dfl_fpga_enum_info_add_dfl(info, start, len);
 	} else {
 		ret = -ENODEV;
-		goto irq_free_exit;
 	}
 
 	/* release I/O mappings for next step enumeration */
 	pcim_iounmap_regions(pcidev, BIT(0));
 
+	return ret;
+}
+
+/* enumerate feature devices under pci device */
+static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
+{
+	struct cci_drvdata *drvdata = pci_get_drvdata(pcidev);
+	struct dfl_fpga_enum_info *info;
+	struct dfl_fpga_cdev *cdev;
+	int nvec, ret = 0;
+	int *irq_table;
+
+	/* allocate enumeration info via pci_dev */
+	info = dfl_fpga_enum_info_alloc(&pcidev->dev);
+	if (!info)
+		return -ENOMEM;
+
+	/* add irq info for enumeration if the device support irq */
+	nvec = cci_pci_alloc_irq(pcidev);
+	if (nvec < 0) {
+		dev_err(&pcidev->dev, "Fail to alloc irq %d.\n", nvec);
+		ret = nvec;
+		goto enum_info_free_exit;
+	} else if (nvec) {
+		irq_table = cci_pci_create_irq_table(pcidev, nvec);
+		if (!irq_table) {
+			ret = -ENOMEM;
+			goto irq_free_exit;
+		}
+
+		ret = dfl_fpga_enum_info_add_irq(info, nvec, irq_table);
+		kfree(irq_table);
+		if (ret)
+			goto irq_free_exit;
+	}
+
+	ret = find_dfls_by_default(pcidev, info);
+	if (ret)
+		goto irq_free_exit;
+
 	/* start enumeration with prepared enumeration information */
 	cdev = dfl_fpga_feature_devs_enumerate(info);
 	if (IS_ERR(cdev)) {