cxl/pci: Cleanup cxl_map_device_regs()

Use a loop to reduce the duplicated code in cxl_map_device_regs(). This
is in preparation for deleting cxl_map_regs().
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/166974409867.1608150.14886452053935226038.stgit@djiang5-desk3.ch.intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/core/regs.c

@@ -211,42 +211,31 @@ int cxl_map_device_regs(struct pci_dev *pdev,
 			struct cxl_device_regs *regs,
 			struct cxl_register_map *map)
 {
+	resource_size_t phys_addr =
+		pci_resource_start(pdev, map->barno) + map->block_offset;
 	struct device *dev = &pdev->dev;
-	resource_size_t phys_addr;
-
-	phys_addr = pci_resource_start(pdev, map->barno);
-	phys_addr += map->block_offset;
-
-	if (map->device_map.status.valid) {
-		resource_size_t addr;
+	struct mapinfo {
+		struct cxl_reg_map *rmap;
+		void __iomem **addr;
+	} mapinfo[] = {
+		{ &map->device_map.status, &regs->status, },
+		{ &map->device_map.mbox, &regs->mbox, },
+		{ &map->device_map.memdev, &regs->memdev, },
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(mapinfo); i++) {
+		struct mapinfo *mi = &mapinfo[i];
 		resource_size_t length;
-
-		addr = phys_addr + map->device_map.status.offset;
-		length = map->device_map.status.size;
-		regs->status = devm_cxl_iomap_block(dev, addr, length);
-		if (!regs->status)
-			return -ENOMEM;
-	}
-
-	if (map->device_map.mbox.valid) {
 		resource_size_t addr;
-		resource_size_t length;
 
-		addr = phys_addr + map->device_map.mbox.offset;
-		length = map->device_map.mbox.size;
-		regs->mbox = devm_cxl_iomap_block(dev, addr, length);
-		if (!regs->mbox)
-			return -ENOMEM;
-	}
-
-	if (map->device_map.memdev.valid) {
-		resource_size_t addr;
-		resource_size_t length;
+		if (!mi->rmap->valid)
+			continue;
 
-		addr = phys_addr + map->device_map.memdev.offset;
-		length = map->device_map.memdev.size;
-		regs->memdev = devm_cxl_iomap_block(dev, addr, length);
-		if (!regs->memdev)
+		addr = phys_addr + mi->rmap->offset;
+		length = mi->rmap->size;
+		*(mi->addr) = devm_cxl_iomap_block(dev, addr, length);
+		if (!*(mi->addr))
 			return -ENOMEM;
 	}