PCI: designware: Look for configuration space in 'reg', not 'ranges'

The configuration address space has so far been specified in *ranges*,
however it should be specified in *reg* making it a platform MEM resource.
Hence used 'platform_get_resource_*' API to get configuration address space
in the designware driver.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Mohit Kumar <mohit.kumar@st.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Marek Vasut <marex@denx.de>
Cc: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/pci/designware-pcie.txt

@@ -2,6 +2,10 @@
 
 Required properties:
 - compatible: should contain "snps,dw-pcie" to identify the core.
+- reg: Should contain the configuration address space.
+- reg-names: Must be "config" for the PCIe configuration space.
+    (The old way of getting the configuration address space from "ranges"
+    is deprecated and should be avoided.)
 - #address-cells: set to <3>
 - #size-cells: set to <2>
 - device_type: set to "pci"

drivers/pci/host/pcie-designware.c

@@ -20,6 +20,7 @@
 #include <linux/of_pci.h>
 #include <linux/pci.h>
 #include <linux/pci_regs.h>
+#include <linux/platform_device.h>
 #include <linux/types.h>
 
 #include "pcie-designware.h"
@@ -396,11 +397,23 @@ static const struct irq_domain_ops msi_domain_ops = {
 int __init dw_pcie_host_init(struct pcie_port *pp)
 {
 	struct device_node *np = pp->dev->of_node;
+	struct platform_device *pdev = to_platform_device(pp->dev);
 	struct of_pci_range range;
 	struct of_pci_range_parser parser;
+	struct resource *cfg_res;
 	u32 val;
 	int i;
 
+	cfg_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "config");
+	if (cfg_res) {
+		pp->config.cfg0_size = resource_size(cfg_res)/2;
+		pp->config.cfg1_size = resource_size(cfg_res)/2;
+		pp->cfg0_base = cfg_res->start;
+		pp->cfg1_base = cfg_res->start + pp->config.cfg0_size;
+	} else {
+		dev_err(pp->dev, "missing *config* reg space\n");
+	}
+
 	if (of_pci_range_parser_init(&parser, np)) {
 		dev_err(pp->dev, "missing ranges property\n");
 		return -EINVAL;
@@ -433,6 +446,8 @@ int __init dw_pcie_host_init(struct pcie_port *pp)
 			of_pci_range_to_resource(&range, np, &pp->cfg);
 			pp->config.cfg0_size = resource_size(&pp->cfg)/2;
 			pp->config.cfg1_size = resource_size(&pp->cfg)/2;
+			pp->cfg0_base = pp->cfg.start;
+			pp->cfg1_base = pp->cfg.start + pp->config.cfg0_size;
 		}
 	}
 
@@ -445,8 +460,6 @@ int __init dw_pcie_host_init(struct pcie_port *pp)
 		}
 	}
 
-	pp->cfg0_base = pp->cfg.start;
-	pp->cfg1_base = pp->cfg.start + pp->config.cfg0_size;
 	pp->mem_base = pp->mem.start;
 
 	pp->va_cfg0_base = devm_ioremap(pp->dev, pp->cfg0_base,